One other interesting thing I found was that many of the extremely large Q frustums can be brought back into line with predicted values by simply dividing the provided Q value by 10.
Because, as we've tried to explain countless times, the Qs in Yang/Shell were grossly overstated. I think Thor is generous when he only divides it by 10.One other interesting thing I found was that many of the extremely large Q frustums can be brought back into line with predicted values by simply dividing the provided Q value by 10.
Why would you do that?
The Demonstrator EMDrive has a stated Q of 45,000 and Df of 0.844.
The data is what it is.
One other interesting thing I found was that many of the extremely large Q frustums can be brought back into line with predicted values by simply dividing the provided Q value by 10.
Why would you do that?
The Demonstrator EMDrive has a stated Q of 45,000 and Df of 0.844.
The data is what it is.
About the only way to resolve this Thor, is to do what you did, adjust reported Q to achieve the reported thrust, given the other parameters remain constant. Once you have static formulae, use Q as the variable to equate reported thrust. Nicely done...One other interesting thing I found was that many of the extremely large Q frustums can be brought back into line with predicted values by simply dividing the provided Q value by 10.
Why would you do that?
The Demonstrator EMDrive has a stated Q of 45,000 and Df of 0.844.
The data is what it is.
Obviously Q isn't Q if everybody's measuring it differently and getting different values.
But mostly, I noticed a trend and thought it was interesting. There was so much controversy swirling around with the whole "how do you calculate Q" thing, and since Q is an integral part of the McCulloch equation I thought I'd play around with it a bit.
One other interesting thing I found was that many of the extremely large Q frustums can be brought back into line with predicted values by simply dividing the provided Q value by 10.
Why would you do that?
The Demonstrator EMDrive has a stated Q of 45,000 and Df of 0.844.
The data is what it is.
Obviously Q isn't Q if everybody's measuring it differently and getting different values.
But mostly, I noticed a trend and thought it was interesting. There was so much controversy swirling around with the whole "how do you calculate Q" thing, and since Q is an integral part of the McCulloch equation I thought I'd play around with it a bit.
One other interesting thing I found was that many of the extremely large Q frustums can be brought back into line with predicted values by simply dividing the provided Q value by 10.
Why would you do that?
The Demonstrator EMDrive has a stated Q of 45,000 and Df of 0.844.
The data is what it is.
Because, as we've tried to explain countless times, the Qs in Yang/Shell were grossly overstated. I think Thor is generous when he only divides it by 10.One other interesting thing I found was that many of the extremely large Q frustums can be brought back into line with predicted values by simply dividing the provided Q value by 10.
Why would you do that?
The Demonstrator EMDrive has a stated Q of 45,000 and Df of 0.844.
The data is what it is.
Want proof? Look at Tajmar's Q, then look at yang/shawyers and tell me why there is a so much disparity. The disparity lies in yang/shawyers unfamiliarity with cavity Q measurement.
I will take the time to explain this one more time, Mr T. after that, either you are deliberately trying to confuse the issue or you simply cannot comprehend.One other interesting thing I found was that many of the extremely large Q frustums can be brought back into line with predicted values by simply dividing the provided Q value by 10.
Why would you do that?
The Demonstrator EMDrive has a stated Q of 45,000 and Df of 0.844.
The data is what it is.
Obviously Q isn't Q if everybody's measuring it differently and getting different values.
But mostly, I noticed a trend and thought it was interesting. There was so much controversy swirling around with the whole "how do you calculate Q" thing, and since Q is an integral part of the McCulloch equation I thought I'd play around with it a bit.
In the experimental EMDrive world of Shawyer, Prof Yang, Eagleworks and Tajmar, unloaded Q is measured and reported as the 3dB down bandwidth from the max return loss dB divided into the resonant frequency.
As Tajmar reported in the attachment.
They all measure their unloaded Q the same way.
Measured resonant frequency at max return loss dB / bandwidth at 3dB down from the peak return loss dBs.
Examples from Eagleworks, Tajmar and Prof Yang. All using the same method to calc unloaded Q.
I will take the time to explain this one more time, Mr T. after that, either you are deliberately trying to confuse the issue or you simply cannot comprehend.
Q = Ctr freq of resonance/3dB bandwidth (total half power bandwidth). Return loss has no bearing on a Q measurement, it MUST be a 2 port measurement, otherwise it is a single-port device akin to an antenna, not a cavity. The calculations used in virtually all relative RF and Microwave circuits calculate Q in the same way, not what yang/shawyer invented.
http://docs.lumerical.com/en/diffractive_optics_cavity_q_calculation.html
"High Q cavities
Derivation of Q factor formula:
The quality factor (Q) is defined as (see image) where wr is the resonant frequency ( ωr=2π fR) and FWHM is the full width half max of the resonance intensity spectrum."
They all measure their unloaded Q the same way.
Measured resonant frequency at max return loss dB / bandwidth at 3dB down from the peak return loss dBs.
Examples from Eagleworks, Tajmar and Prof Yang. All using the same method to calc unloaded Q.
You are absolutely, 100% right. I hereby defer to you in all future disagreements. I apologize for my impertinence. My spreadsheet is wrong and your spreadsheet is right.
The calculations used in virtually all relative RF and Microwave circuits calculate Q in the same way, not what yang/shawyer invented.
The testiness of this current discussion aside, I am genuinely interested in the reason why there is a difference between these two Q value viewpoints.
The testiness of this current discussion aside, I am genuinely interested in the reason why there is a difference between these two Q value viewpoints.
but in all cases, they are doing it wrong and should be using 2 ports to measure cavity resonance. We have yet to see anyone do it this way.
Todd
The testiness of this current discussion aside, I am genuinely interested in the reason why there is a difference between these two Q value viewpoints.
As far as I can gather, @TT is saying, "How they did it". @rfmwguy is saying "How it should've been done." and @tleach is saying "This is how it seems to fit McCulloch's formula."
Which BTW, McCulloch doesn't define how to measure Q. He simply redefines it as the number of bounces (reflections), in the time it takes the photon to decay to zero. So that's not even the same definition of the Q that is being kicked around here. @tleach was trying to bridge that gap.
What I conclude is, the experimenters may or may not be measuring it consistently using the same methodology, but in all cases, they are doing it wrong and should be using 2 ports to measure cavity resonance. We have yet to see anyone do it this way.
Todd
The testiness of this current discussion aside, I am genuinely interested in the reason why there is a difference between these two Q value viewpoints.
In the EMDrive world measuring unloaded Q via S11 return loss at the 3bd down bandwidth is how it is measured.
So say Shawyer, Prof Yang, Eagleworks and Prof Tajmar.
It would be oh-so-simple to resolve this. Send a closed, resonant cavity to NIST, the British Standards Institute (BSI) or other reputable body with ONLY 1 PORT and have them measure Q. After they ask where the other port is, they would ask, why would you want to measure a closed cavity system with only one port? IOW, an open system, like an antenna, only needs a single port. A resonant cavity needs 2 to properly measure Q.The testiness of this current discussion aside, I am genuinely interested in the reason why there is a difference between these two Q value viewpoints.
As far as I can gather, @TT is saying, "How they did it". @rfmwguy is saying "How it should've been done." and @tleach is saying "This is how it seems to fit McCulloch's formula."
Which BTW, McCulloch doesn't define how to measure Q. He simply redefines it as the number of bounces (reflections), in the time it takes the photon to decay to zero. So that's not even the same definition of the Q that is being kicked around here. @tleach was trying to bridge that gap.
What I conclude is, the experimenters may or may not be measuring it consistently using the same methodology, but in all cases, they are doing it wrong and should be using 2 ports to measure cavity resonance. We have yet to see anyone do it this way.
Todd
???It would be oh-so-simple to resolve this. Send a closed, resonant cavity to NIST, the British Standards Institute (BSI) or other reputable body with ONLY 1 PORT and have them measure Q. After they ask where the other port is, they would ask, why would you want to measure a closed cavity system with only one port? IOW, an open system, like an antenna, only needs a single port. A resonant cavity needs 2 to properly measure Q.The testiness of this current discussion aside, I am genuinely interested in the reason why there is a difference between these two Q value viewpoints.
As far as I can gather, @TT is saying, "How they did it". @rfmwguy is saying "How it should've been done." and @tleach is saying "This is how it seems to fit McCulloch's formula."
Which BTW, McCulloch doesn't define how to measure Q. He simply redefines it as the number of bounces (reflections), in the time it takes the photon to decay to zero. So that's not even the same definition of the Q that is being kicked around here. @tleach was trying to bridge that gap.
What I conclude is, the experimenters may or may not be measuring it consistently using the same methodology, but in all cases, they are doing it wrong and should be using 2 ports to measure cavity resonance. We have yet to see anyone do it this way.
Todd
I'll stand by this (un)controversial position regardless of the previous experimenters. Quite frankly, I'm surprised at their apparent lack of RF familiarity. This is not a slam, it is a known fact that RF engineering is taught less, practiced less and is receeding into the background of companies and institutions. Reason? Computer science boom and the "plug and play & throw away" mentality of electronics in general.
Open system = 1 port
Closed system (frustum) = 2 port
Case closed. Its the last I will post on this matter at NSF.
I think the reason why all the EmDrive experimenters to date (Shawyer, Yang, Brady/White, Tajmar) measured the unloaded Q (or Qu) as the S11 1 port return loss (resonant frequency at maximum return loss dB -3dB off this peak return loss dB value) is not because they would not know or don't want to use the more official S22 2-port method, but because the Qu they get from the S11 1-port method is just a suitable value that can be plugged readily into their equations to calculate and predict theoretical thrust. Obviously the S22 2-port value does not provide a value usable to calculate thrust, at least according to their equations.transmission measurement is S12 or S21
I think the reason why all the EmDrive experimenters to date (Shawyer, Yang, Brady/White, Tajmar) measured the unloaded Q (or Qu) as the S11 1 port return loss (resonant frequency at maximum return loss dB -3dB off this peak return loss dB value) is not because they would not know or don't want to use the more official S22 2-port method, but because the Qu they get from the S11 1-port method is just a suitable value that can be plugged readily into their equations to calculate and predict theoretical thrust. Obviously the S22 2-port value does not provide a value usable to calculate thrust, at least according to their equations.transmission measurement is S12 or S21
but in all cases, they are doing it wrong and should be using 2 ports to measure cavity resonance. We have yet to see anyone do it this way.
Todd
So Dr. Ray Kwok is also wrong?
Just a question regarding the Q measurement :Does everyone knows about the inner impedance of a oven magnetron?
Even if we know that the Q's are/were measured in the wrong way, wouldn't it be wise to continue with the faulty system, in order to make all those test comparative?
If measurement standards are changed now to the correct method, all the data we have up till now becomes inaccurate or no longer useable, no?
One can question the validity of the previous information bits that have been gathered, but this sure will not help... throw it all overboard then? ???
Q = f / deltaF
where deltaF is the frequency spread between lower and upper -3 dB points.
I think the differences discussed stem from how that -3 dB is measured, no?
Q = f / deltaFFor a 1 port measurement may be.
where deltaF is the frequency spread between lower and upper -3 dB points.
I think the differences discussed stem from how that -3 dB is measured, no?
Not coming from the RF world, I wonder why this whole discussion about Q can't settle on Q=2*π*energy_stored/energy_dissipated_per_cycle as a standard. Out of curiosity, isn't it possible to switch off a RF source fast enough (a few cycles) and get this Q value by observing only the time constant of the decay of amplitude with a minimally invasive probe ?
BTW, not wanting to sound insistent but there is no answer to my questions about the relation of Q and "losses per round trip" (http://forum.nasaspaceflight.com/index.php?topic=37642.msg1414001#msg1414001) (in the context of a linear resonant set up). If I am making a mistake by thinking "number of bounces" when hearing Q, then I'm not the only one : Think of it like the number of times a photon bounces inside a mirrored cavity. (https://www.reddit.com/r/EmDrive/comments/3fz91k/in_an_emdrive_q_rules/cttks09) A clarification might be useful.
Todd, but the axial force component due to the side walls equals Sin[theta]*SideWallForce, where theta is the cone half-angle. For theta = 0 ( a cylinder) the axial component due to the SideWallForce is Sin[0]*SideWallForce=0, it is zero no matter how large is the SideWallForce. For small theta, the SideWallForce axial component is very low. So, even if one grants you that the SideWallForce may be larger for small cone angle, the axial component is small. Comments?Not coming from the RF world, I wonder why this whole discussion about Q can't settle on Q=2*π*energy_stored/energy_dissipated_per_cycle as a standard. Out of curiosity, isn't it possible to switch off a RF source fast enough (a few cycles) and get this Q value by observing only the time constant of the decay of amplitude with a minimally invasive probe ?
BTW, not wanting to sound insistent but there is no answer to my questions about the relation of Q and "losses per round trip" (http://forum.nasaspaceflight.com/index.php?topic=37642.msg1414001#msg1414001) (in the context of a linear resonant set up). If I am making a mistake by thinking "number of bounces" when hearing Q, then I'm not the only one : Think of it like the number of times a photon bounces inside a mirrored cavity. (https://www.reddit.com/r/EmDrive/comments/3fz91k/in_an_emdrive_q_rules/cttks09) A clarification might be useful.
My conjecture on this would be that, a small cone angle will cause more bounces and a higher Q. However, my feeling is that as the wave propagates from the small end to the big end, it is reflecting off the side walls. Each reflection off the side walls imparts a tiny bit of momentum to the frustum. So the more bounces off the side walls (not the end plates) will produce more thrust. This means that a slower group velocity, bouncing over a longer period of time, would give higher thrust. This leads to the idea that the frustum should be shaped more like a trombone with a long throat. But... none of the theories so far support this idea, but none have tried either.
Todd
Todd, but the axial force component due to the side walls equals Sin[theta]*SideWallForce, where theta is the cone half-angle. For theta = 0 ( a cylinder) the axial component due to the SideWallForce is Sin[0]*SideWallForce=0, it is zero no matter how large is the SideWallForce. For small theta, the SideWallForce axial component is very low. So, even if one grants you that the SideWallForce may be larger for small cone angle, the axial component is small. Comments?Not coming from the RF world, I wonder why this whole discussion about Q can't settle on Q=2*π*energy_stored/energy_dissipated_per_cycle as a standard. Out of curiosity, isn't it possible to switch off a RF source fast enough (a few cycles) and get this Q value by observing only the time constant of the decay of amplitude with a minimally invasive probe ?
BTW, not wanting to sound insistent but there is no answer to my questions about the relation of Q and "losses per round trip" (http://forum.nasaspaceflight.com/index.php?topic=37642.msg1414001#msg1414001) (in the context of a linear resonant set up). If I am making a mistake by thinking "number of bounces" when hearing Q, then I'm not the only one : Think of it like the number of times a photon bounces inside a mirrored cavity. (https://www.reddit.com/r/EmDrive/comments/3fz91k/in_an_emdrive_q_rules/cttks09) A clarification might be useful.
My conjecture on this would be that, a small cone angle will cause more bounces and a higher Q. However, my feeling is that as the wave propagates from the small end to the big end, it is reflecting off the side walls. Each reflection off the side walls imparts a tiny bit of momentum to the frustum. So the more bounces off the side walls (not the end plates) will produce more thrust. This means that a slower group velocity, bouncing over a longer period of time, would give higher thrust. This leads to the idea that the frustum should be shaped more like a trombone with a long throat. But... none of the theories so far support this idea, but none have tried either.
Todd
http://www.ustream.tv/channel/em-drive-experimentYOU ROCK! Couldn't login for whatever reason. But no questions.
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Thanks Shell...it was fun...a dry run for the fulcrum test in a couple of weeks. Think we had 24 viewers, not bad for short notice only here on NSF.http://www.ustream.tv/channel/em-drive-experimentYOU ROCK! Couldn't login for whatever reason. But no questions.
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Shell
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Thinking about the ongoing controversy regarding TheTraveller's and Shawyer's theory raises a question for me. Please forgive if this has been addressed in one of the earlier threads.
If Shawyer's theory is wrong then is Cullen's eqn 15 also incorrect?? Eqn 15 seems to be the bedrock of the theory (the bible they punch :D).
I am trying to unpack the controversy a bit from the recent standard of "the physics/theory is wrong".
Thinking about the ongoing controversy regarding TheTraveller's and Shawyer's theory raises a question for me. Please forgive if this has been addressed in one of the earlier threads.
If Shawyer's theory is wrong then is Cullen's eqn 15 also incorrect?? Eqn 15 seems to be the bedrock of the theory (the bible they punch :D).
I am trying to unpack the controversy a bit from the recent standard of "the physics/theory is wrong".
Cullen is discussing a constant cross section wave guide the resonator that Shawyer is trying to analyze is a more complicated shape so Cullen's equation may or may not be applicable. There is probably something wrong with Shawyer's equation 7 since it ignores forces on the side walls. There are proofs in EM theory that show that EM waves will produces a time averaged net 0 force for any shape cavity, and any result that contradicts this either has incorrect math, or an assumption inconsistent with Maxwell's equations i.e. new physics.
If you are looking for a specific part of Shawyer's paper that is wrong, just after equation 7, he applies the special relativity velocity addition formula. This formula is used to transform the velocity of something measured in one reference frame to the velocity that object would appear to have in another reference frame. Shawyer applies it to a random equation that he had rearranged to have a subtraction of velocities. He is not transforming reference frames, so applying the formula there is nonsense.
When he calculates the forces on the 2 plates separately for a waveguide moving at a different velocity, he is using the equation in the right context, but fails to account for the fact that he has to transform all of the variables into the moving reference frame. Some quantities that change are the cavity length, resonance frequency, injected frequency, and the energy stored in the waves. His claims of thrust reversing at a high fraction of the speed of light are a symptom of this misapplication of special relativity.
The fact that his paper's conclusions are completely wrong is sufficiently obvious to most experts that they don't even bother looking for what his specific mistakes are. The experimental results from multiple labs are another story, and those results are the only reason the EM drive is not completely dismissed.
but in all cases, they are doing it wrong and should be using 2 ports to measure cavity resonance. We have yet to see anyone do it this way.
Todd
So Dr. Ray Kwok is also wrong?
I see nothing incorrect about what Dr. Kwok said. He said "Resonators". An antenna is a resonator and so is a cavity. One is an open system, the other is a closed system. The preferred methods are different at a "National Standards" level, according to @rfmwguy. While I agree 100% that the experimenters to date have consistently used the S11 method, that does not mean it is the "standard" way to do it. You are arguing that "In the EM Drive world" this is how it's done. Perhaps this is true, but is no less true that this is NOT the "standard" way to do it.
Stop arguing about it and accept that fact please. You're driving everyone bonkers with your obstinance and defense of obvious incongruences. I do not follow others. I make mistakes, try to understand learn from them and forge my own path and from what I've seen, that is how most of us here operate.
Todd
The testiness of this current discussion aside, I am genuinely interested in the reason why there is a difference between these two Q value viewpoints.
As far as I can gather, @TT is saying, "How they did it". @rfmwguy is saying "How it should've been done." and @tleach is saying "This is how it seems to fit McCulloch's formula."
Which BTW, McCulloch doesn't define how to measure Q. He simply redefines it as the number of bounces (reflections), in the time it takes the photon to decay to zero. So that's not even the same definition of the Q that is being kicked around here. @tleach was trying to bridge that gap.
What I conclude is, the experimenters may or may not be measuring it consistently using the same methodology, but in all cases, they are doing it wrong and should be using 2 ports to measure cavity resonance. We have yet to see anyone do it this way.
Todd
SPR has declined my license request.
Too much red tape with using Chinese frustum fabricators and my Australian company would need to be approved by both UK and Australian Depts of Defense.
Oh well at least I tried to do the right thing.
SPR has declined my license request.
Too much red tape with using Chinese frustum fabricators and my Australian company would need to be approved by both UK and Australian Depts of Defense.
Oh well at least I tried to do the right thing.
As a practical matter will this affect you much? Just trying to understand the implications of this. Thanks!
SPR has declined my license request.
Too much red tape with using Chinese frustum fabricators and my Australian company would need to be approved by both UK and Australian Depts of Defense.
Oh well at least I tried to do the right thing.
As a practical matter will this affect you much? Just trying to understand the implications of this. Thanks!
Should have very little effect.
Was just trying to do the right thing by Shawyer / SPR and not be called out for ripping off the IP.
Told Shawyer I'll still give him / SPR 25% of any gross profit made.
SPR has declined my license request.
Too much red tape with using Chinese frustum fabricators and my Australian company would need to be approved by both UK and Australian Depts of Defense.
Oh well at least I tried to do the right thing.
As a practical matter will this affect you much? Just trying to understand the implications of this. Thanks!
Should have very little effect.
Was just trying to do the right thing by Shawyer / SPR and not be called out for ripping off the IP.
Told Shawyer I'll still give him / SPR 25% of any gross profit made.
Wouldn't you agree, that the waves have the highest momentum when the cone angle is smallest and k*r is the largest?
It is only the reflection at the big end that opposes this force. Anything that can be done to minimize the "z" component of this reflection, will add to the thrust.
Todd
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Hi Thor,Quote from: rfmwguy link=topic=37642.msg1413139#msg1413139Thermal tests done including 5 minute run at 30% power, which is what I'll use for fulcrum test. What I learned: Matching into frustum is good, magnetron ran at temperatures well below 200°C. Still had minor arcing, corrected it with full teardown and replacement of Db with mesh only, no copper clad. IOW, frustum is now all mesh except for Ds where magnetron is mounted. There was no arcing on Ds throughout any thermal testing. Plasma focused on Db, interestingly enough diagonally across from radome, not directly across axially.
@rfmwguy
"Thermal tests done including 5 minute run at 30% power, which is what I'll use for fulcrum test." So you're actually putting in 30% of 900W which would be approximately 270W.
And then there's the conversion of electrical energy into microwave energy. If we assume that wikepedia is correct, a 900W microwave oven magnetron should run with approximately 64% efficiency.
https://en.wikipedia.org/wiki/Microwave_oven#Heating_efficiency
That means you're magnetron is only putting 172.8W of energy into your frustum. I'm officially revising my force prediction (based on my v3 spreadsheet and a projected S12 Q factor of 7000) down 43.41 mN.
Sorry :-)
I dunno, Star, have given that some thought, even getting some of my film crew buddies out to the shop to document it 3rd-party...but have enough reservations remaining that I'll just let NSF pals spread the word themselves.http://www.ustream.tv/channel/em-drive-experiment
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Jose,
In Zeng & Fan they define the complex wave number propagating toward the small end as;
k = j*α - β, where j is the imaginary coordinate.
Momentum is directly proportional to k. So the squared magnitude of the momentum vector is proportional to;
k2 = α2 + β2
Now, take a gander at the plots for attenuation and phase constant in Zeng & Fan. Which mode and cone half-angle do you think will have the highest momentum?
For TE modes, as β goes to 0, the wave is 100% attenuated at the small end. They refer to this as the cut-off.
Wouldn't you agree, that the waves have the highest momentum when the cone angle is smallest and k*r is the largest?
Also, if the attenuation, α is asymmetrical, would the equation above not (rather simply) explain beyond doubt why momentum transfer is also asymmetrical?
@TheTraveler likes to use Guide wavelength, rather than phase velocity. So be it. The guide wavelength is the inverse;
λguide = 2*pi/β
Per Z&F, as α increases, β goes to 0, the guide wavelength will become infinitely long and momentum of the wave goes to zero. It is 100% attenuated and absorbed at the front end.
Going the other way, toward the big end, β is increasing and α is decreasing rapidly. The momentum of the wave is increasing.
In both directions, the force on the frustum which balances the change in momentum is "forward". It is only the reflection at the big end that opposes this force. Anything that can be done to minimize the "z" component of this reflection, will add to the thrust.
Todd
I dunno, Star, have given that some thought, even getting some of my film crew buddies out to the shop to document it 3rd-party...but have enough reservations remaining that I'll just let NSF pals spread the word themselves.http://www.ustream.tv/channel/em-drive-experiment
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When you do the real thing are you going to publicise more widely?
Should positive results be achieved, and I believe enough in them, I'll get a film crew out to professionally video it. I'm sure they or perhaps a local TV station would be interested in shooting a "mad scientist" feature spot.
Way too early for that. Getting them out for null results would be a bad deal for everyone. Besides, I have to clean up the shop first ;)
We note that if the forces had been the mechanical result of a working fluidSource of image:
within the closed waveguide assembly, then the resultant force would merely
introduce a mechanical strain in the waveguide walls. This would be the result of a
closed system of waveguide and working fluid.
In the present system the working fluid is replaced by an electromagnetic
wave propagating close to the speed of light and Newtonian mechanics must be
replaced with the special theory of relativity. There are two effects to be considered
in the application of the special theory of relativity to the waveguide. The first effect
is that as the two forces Fg1 and Fg2 are dependent upon the velocities vg1 and vg2, the
thrust T should be calculated according to Einstein’s law of addition of velocities
given by
(https://upload.wikimedia.org/math/2/0/3/2035aab1ba5af2e1ff296512b6a57779.png)
The second effect is that as the beam velocities are not directly dependent on
any velocity of the waveguide, the beam and waveguide form an open system. Thus
the reactions at the end plates are not constrained within a closed system of
waveguide and beam but are reactions between waveguide and beam, each operating
within its own reference frame, in an open system.
When light propagates in fibre optic cable, the setup is effectively a combination of a Sagnac experiment and the Fizeau experiment. In glass the speed of light is slower than in vacuum, and the optical cable is the moving medium. In that case the relativistic velocity addition rule applies.
Not making any claims here, just reporting what I read. Keeping an open mind and poking around a bit.If you really want to dive deep, look at Orbital Angular Momentum of circular radiation:
Been reading up on how Shawyer "opens" up the Emdrive in his theory paper.
http://www.emdrive.com/theorypaper9-4.pdf
Specifically his use of Einstein's law of addition of velocities:QuoteWe note that if the forces had been the mechanical result of a working fluidSource of image:
within the closed waveguide assembly, then the resultant force would merely
introduce a mechanical strain in the waveguide walls. This would be the result of a
closed system of waveguide and working fluid.
In the present system the working fluid is replaced by an electromagnetic
wave propagating close to the speed of light and Newtonian mechanics must be
replaced with the special theory of relativity. There are two effects to be considered
in the application of the special theory of relativity to the waveguide. The first effect
is that as the two forces Fg1 and Fg2 are dependent upon the velocities vg1 and vg2, the
thrust T should be calculated according to Einstein’s law of addition of velocities
given by
(https://upload.wikimedia.org/math/2/0/3/2035aab1ba5af2e1ff296512b6a57779.png)
The second effect is that as the beam velocities are not directly dependent on
any velocity of the waveguide, the beam and waveguide form an open system. Thus
the reactions at the end plates are not constrained within a closed system of
waveguide and beam but are reactions between waveguide and beam, each operating
within its own reference frame, in an open system.
https://en.wikipedia.org/wiki/Velocity-addition_formula#Special_relativity
I remember reading lots of criticism for Shawyer using the addition of velocities from SR.
So I went looking around for where it is okay to use the addition of velocities. I went poking around to see what I could learn while keeping in mind that the EMdrives have air within the cavity with a refractive index not equal to 1 (1.000277) have been shown to present more thrust than airless cavities.
Ended up here:
https://en.wikipedia.org/wiki/Sagnac_effect (yeah I know, it's been brought up before)QuoteWhen light propagates in fibre optic cable, the setup is effectively a combination of a Sagnac experiment and the Fizeau experiment. In glass the speed of light is slower than in vacuum, and the optical cable is the moving medium. In that case the relativistic velocity addition rule applies.
So it looks like the line in the sand is centered around the invariant speed of light in vacuum vs the speed of light in a medium (not a constant). Anyone able to mythbust any of this? Is the criticism that Shawyer is wrong in using the above addition of velocities warranted?
Which lead me to poke around looking for info related to the Fizeau experiment.
https://en.wikipedia.org/wiki/Fizeau_experiment (there was some dragging detected)
But then I was thinking of old Michelson-Morley experiment and those that followed:
https://en.wikipedia.org/wiki/Michelson%E2%80%93Gale%E2%80%93Pearson_experiment
http://www.kritik-relativitaetstheorie.de/Anhaenge/Wolfgang-Engelhardt-Sagnac.pdf (Originally posted in thread 2 by @Rodal)
So all I have to say after all that, it seems very important to see whether or not thrust differs when the frustum is oriented both parallel and perpendicular to Earth's rotation.
Jose,
In Zeng & Fan they define the complex wave number propagating toward the small end as;
k = j*α - β, where j is the imaginary coordinate.
Momentum is directly proportional to k. So the squared magnitude of the momentum vector is proportional to;
k2 = α2 + β2
Now, take a gander at the plots for attenuation and phase constant in Zeng & Fan. Which mode and cone half-angle do you think will have the highest momentum?
For TE modes, as β goes to 0, the wave is 100% attenuated at the small end. They refer to this as the cut-off.
Wouldn't you agree, that the waves have the highest momentum when the cone angle is smallest and k*r is the largest?
Also, if the attenuation, α is asymmetrical, would the equation above not (rather simply) explain beyond doubt why momentum transfer is also asymmetrical?
@TheTraveler likes to use Guide wavelength, rather than phase velocity. So be it. The guide wavelength is the inverse;
λguide = 2*pi/β
Per Z&F, as α increases, β goes to 0, the guide wavelength will become infinitely long and momentum of the wave goes to zero. It is 100% attenuated and absorbed at the front end.
Going the other way, toward the big end, β is increasing and α is decreasing rapidly. The momentum of the wave is increasing.
In both directions, the force on the frustum which balances the change in momentum is "forward". It is only the reflection at the big end that opposes this force. Anything that can be done to minimize the "z" component of this reflection, will add to the thrust.
Todd
Momentum is a vector. What matters is the component of the momentum on the lateral walls acting along the longitudinal axis, so you have to multiply it by Sin[θ]:
Sin[θ]*MomentumLateralWalls where θ=cone half-angle
(http://gregegan.customer.netspace.net.au/SCIENCE/Cavity/CavityShape.gif)
while the transverse components
Cos[θ]*MomentumLateralWalls
are self-cancelling (since the component on the left wall act in opposite direction to the one in the right wall). Thus, if one assumes what you propose is correct (*), what matters is the vector component of momentum on the lateral walls, the component oriented along the longitudinal axis of the cone: Sin[θ]*Abs[k] where θ is the half-cone angle, so for θ=0, this component is zero. Any finite magnitude multiplied by zero gives a zero result. So obviously a cylinder (θ=0) is the worst situation, as the longitudinal component of lateral-wall momentum is zero. For θ=0, Sin[θ]*Abs[k] is zero, as θ increases, k decreases, but Sin[θ] increases. As to what is the optimal value of the cone half-angle θ, one would have to calculate the expressions to find out.
If you don't multiply the Momentum by Sin[θ], then one arrives at the wrong conclusion: that a cylinder is best. To arrive at the correct conclusion, one has to multiply Momentum by Sin[θ].
(*) To know, one would have to calculate the Hankel functions and see how the absolute value of k varies as a function of cone angle θ and k r
...But Z&F give k in the direction of r, not perpendicular to the axis. So the k value I'm using is already "in" that direction. What am I missing in Z&F that says otherwise?In expression 9 of Zeng and Fan's paper
Todd
Based on the Eqs. (12), (13) and (14), a variation of the attenuation α and phase constants β
for the spherical TE and TM modes as a function of kr with cone half-angle 0 θ as a
parameter has been studied and the results are presented in Figs. 2-5.
...But Z&F give k in the direction of r, not perpendicular to the axis. So the k value I'm using is already "in" that direction. What am I missing in Z&F that says otherwise?In expression 9 of Zeng and Fan's paper
Todd
Electromagnetic fields and transmission properties in tapered hollow metallic waveguides
Xiahui Zeng and Dianyuan Fan
https://www.osapublishing.org/oe/fulltext.cfm?uri=oe-17-1-34&id=175583
Zeng and Fan define k sub r in the r direction
Then suddenly in expressions 12, 13 and 14 they give an expression for gamma sub [θ ,φ] in terms of a k that has no subscript.
Ricvl has called these expressions 12 to 14 into question, as to whether they satisfy the Boundary Conditions. I find it peculiar that Zeng and Fan droped the r subscript in these expressions 12-14, and that they replace gamma with gamma sub [θ, φ]
I have not re-derived them on my own to see whether they are correct, or whether they satisfy the Boundary Conditions or what does k stand for in these expressions.
From a physical standpoint it does not make any sense to me that the longitudinal component should be maximum for θ =0. For θ =0 the longitudinal component of momentum should be zero, so either Ricvl is correct that these expressions do not satisfy the Boundary Conditions, or k in these expresssions is not k sub r and gamma is not in the r direction.
Inspection of the subscript for gamma in equations 12 to 14 reveals that this is indeed the case.
The expressions 12 to 14 are labeled as gamma sub [θ, φ], therefore my interpretation is that they clearly are the components perpendicular to r, since the coordinates θ, φ are perpendicular to r.
Therefore it seems to me that a gamma component in the θ direction should be multplied by Sin[θ] to get the component in the longitudinal direction.
...
Okay, back to the drawing board!
Thanks!
Todd
For those who are too skittish to be associated with doing Emdrive experiments, would recasting it as yet another Aether drag experiment sound any better?Which kind of symmetry do you mean?
https://en.wikipedia.org/wiki/Michelson%E2%80%93Morley_experiment#Recent_optical_resonator_experiments
Have any recent experiments featured any intentional symmetry breaking?
Parity and Timespontaneous symmetry breaking is the why we(and the universe) are here and the why we can ask such questions 8)
...
Okay, back to the drawing board!
Thanks!
Todd
Please notice that while Fig. 2 and 3 in Zeng and Fan correspond to the electric field in the θ and φ directions, Fig 4 and 5 correspond to the electric field in the r direction. Only the TM modes have an electric field in the r direction.
They define the attenuation only for the electric field, so they don't have a figure for magnetic field in the r direction corresponding to the TE modes.
For those who are too skittish to be associated with doing Emdrive experiments, would recasting it as yet another Aether drag experiment sound any better?Which kind of symmetry do you mean?
https://en.wikipedia.org/wiki/Michelson%E2%80%93Morley_experiment#Recent_optical_resonator_experiments
Have any recent experiments featured any intentional symmetry breaking?
complex issue...
That's symmetry breaking par excellence, never the B field curls in the opposite direction while the current flows in the direction like in the drawing ;)
source of the picture: http://wiki.bnv-bamberg.de/flg-wiki/index.php/SchulheftPh9
Gravity is another example (till now there is only attractive force). :)
...
Okay, back to the drawing board!
Thanks!
Todd
Please notice that while Fig. 2 and 3 in Zeng and Fan correspond to the electric field in the θ and φ directions, Fig 4 and 5 correspond to the electric field in the r direction. Only the TM modes have an electric field in the r direction.
They define the attenuation only for the electric field, so they don't have a figure for magnetic field in the r direction corresponding to the TE modes.
Correct. The attenuation is on E perpendicular to the walls, since there is no radial component and no component tangential to the walls. However, the momentum in the r direction, depends on E perpendicular to r. So the attenuation of E perpendicular to r, affects the momentum in the r direction without multiplication by Sin(theta).
If you follow from equation 8 to 9, the expression j*kr=-(1/E)*dE/dr, is an expression for momentum in the r direction. To get momentum in the z direction, you would multiply by Cos(theta), but for small cone angles it's negligible.
Equation 8 is fairly straight forward, the wave is propagating in the r direction, and equation 9 shows it is expanding or contracting depending on direction. Take the derivative of 9 wrt t and multiply by Planck's constant to get the force, dp/dt. For which I get; (E is the electric field, not energy!!!)
Fr = -(hbar*kr/E)*dE/dt -j*hbar*d/dt(dE/dr)
= -(hbar*kr/E)*dE/dt -j*(hbar/c)*d2E/dt2) (I don't think I should use c here for dr/dt, but you get the idea. It's a wave equation.)
For Fz = Fr * Cos(theta)
Comments?
Todd
You can't form a cylinder this way, r is the distance from the apex ;) that's never parallel. For the boundary conditions i have to think about, but your comment 2) make sense to me...
Okay, back to the drawing board!
Thanks!
Todd
Please notice that while Fig. 2 and 3 in Zeng and Fan correspond to the electric field in the θ and φ directions, Fig 4 and 5 correspond to the electric field in the r direction. Only the TM modes have an electric field in the r direction.
They define the attenuation only for the electric field, so they don't have a figure for magnetic field in the r direction corresponding to the TE modes.
Correct. The attenuation is on E perpendicular to the walls, since there is no radial component and no component tangential to the walls. However, the momentum in the r direction, depends on E perpendicular to r. So the attenuation of E perpendicular to r, affects the momentum in the r direction without multiplication by Sin(theta).
If you follow from equation 8 to 9, the expression j*kr=-(1/E)*dE/dr, is an expression for momentum in the r direction. To get momentum in the z direction, you would multiply by Cos(theta), but for small cone angles it's negligible.
Equation 8 is fairly straight forward, the wave is propagating in the r direction, and equation 9 shows it is expanding or contracting depending on direction. Take the derivative of 9 wrt t and multiply by Planck's constant to get the force, dp/dt. For which I get; (E is the electric field, not energy!!!)
Fr = -(hbar*kr/E)*dE/dt -j*hbar*d/dt(dE/dr)
= -(hbar*kr/E)*dE/dt -j*(hbar/c)*d2E/dt2) (I don't think I should use c here for dr/dt, but you get the idea. It's a wave equation.)
For Fz = Fr * Cos(theta)
Comments?
Todd
I would have to re-derive them myself, but:
1) From a physical standpoint it does not make any sense to me that the longitudinal component should be maximum for θ =0. For θ =0 the longitudinal component of momentum should be zero, so either Ricvl is correct that these expressions do not satisfy the Boundary Conditions, or gamma is not in the r direction.
2) The expressions 12 to 13 are labeled as gamma sub [θ, φ], therefore my interpretation is that they clearly are the components perpendicular to r, since the coordinates θ, φ are perpendicular to r. Therefore it seems to me that a gamma component in the θ direction should be multplied by Sin[θ] to get the component in the longitudinal direction.
I have to re-derive them myself to make any further comments. #1 ( it does not make any sense to me that the longitudinal component should be maximum for θ =0 which implies that a cylinder is best) is a big obstacle in me being able to agree that it is correct without mulitplying by Sin[θ]
Sorry, I cannot take Zeng and Fan's results for granted if they imply that the longitudinal component of momentum should be maximum for θ =0
...I had that discussion with Todd in a previous thread, where he wrote the same thing you wrote above.
You can't form a cylinder this way, r is the distance from the apex ;) that's never parallel. For the boundary conditions i have to think about, but your comment 2) make sense to me
...
Okay, back to the drawing board!
Thanks!
Todd
Please notice that while Fig. 2 and 3 in Zeng and Fan correspond to the electric field in the θ and φ directions, Fig 4 and 5 correspond to the electric field in the r direction. Only the TM modes have an electric field in the r direction.
They define the attenuation only for the electric field, so they don't have a figure for magnetic field in the r direction corresponding to the TE modes.
Correct. The attenuation is on E perpendicular to the walls, since there is no radial component and no component tangential to the walls. However, the momentum in the r direction, depends on E perpendicular to r. So the attenuation of E perpendicular to r, affects the momentum in the r direction without multiplication by Sin(theta).
If you follow from equation 8 to 9, the expression j*kr=-(1/E)*dE/dr, is an expression for momentum in the r direction. To get momentum in the z direction, you would multiply by Cos(theta), but for small cone angles it's negligible.
Equation 8 is fairly straight forward, the wave is propagating in the r direction, and equation 9 shows it is expanding or contracting depending on direction. Take the derivative of 9 wrt t and multiply by Planck's constant to get the force, dp/dt. For which I get; (E is the electric field, not energy!!!)
Fr = -(hbar*kr/E)*dE/dt -j*hbar*d/dt(dE/dr)
= -(hbar*kr/E)*dE/dt -j*(hbar/c)*d2E/dt2) (I don't think I should use c here for dr/dt, but you get the idea. It's a wave equation.)
For Fz = Fr * Cos(theta)
Comments?
Todd
I would have to re-derive them myself, but:
1) From a physical standpoint it does not make any sense to me that the longitudinal component should be maximum for θ =0. For θ =0 the longitudinal component of momentum should be zero, so either Ricvl is correct that these expressions do not satisfy the Boundary Conditions, or gamma is not in the r direction.
2) The expressions 12 to 14 are labeled as gamma sub [θ, φ], therefore my interpretation is that they clearly are the components perpendicular to r, since the coordinates θ, φ are perpendicular to r. Therefore it seems to me that a gamma component in the θ direction should be multplied by Sin[θ] to get the component in the longitudinal direction.
I have to re-derive them myself to make any further comments. #1 ( it does not make any sense to me that the longitudinal component should be maximum for θ =0 which implies that a cylinder is best) is a big obstacle in me being able to agree that it is correct without mulitplying by Sin[θ]
...
In a cylinder, the longitudinal component of momentum is the wave propagating down the waveguide. The momentum is in the z direction, not radial toward the walls. In Z&F, they are depicting a waveguide, not a cavity. The momentum is propagating down the waveguide. Changing the angle > 0, changes the momentum in the z direction for a tapered waveguide, relative to a cylindrical waveguide. In the case of the wave moving toward the apex, what Z&F show is that the waves are attenuated and all of the momentum in the z direction is phase shifted and absorbed.
Essentially, attenuation of the E field in the perpendicular directions, "IS" attenuation of momentum in the r direction, because Sr = E x H perpendicular to S. The wave traveling toward the apex is losing momentum to the waveguide, in the z direction. The wave traveling toward the big end is gaining momentum in the z direction. In a cylinder, neither is true because the wave does not change momentum in either direction. So the k-vector reflecting off the wall is not (theta, phi) in Z&F, it is in the r direction. So it is r*Cos(theta) to get z direction thrust.
Todd
Yeah right it's negligible for huge values of r, sometime the difference of r1 and r2 reach Plank length and there is no longer a difference in a physical sense....I had that discussion with Todd in a previous thread, where he wrote the same thing you wrote above.
You can't form a cylinder this way, r is the distance from the apex ;) that's never parallel. For the boundary conditions i have to think about, but your comment 2) make sense to me
That's wrong.
I submitted a formal proof that a cylinder is the limit for r2 ->Infinity with (r2 - r1) kept constant and theta -> 0. Although I derived my proof independently you can also find in Euclidean geometry books, it emanates from the last of Euclid's postulate (parallell lines never meet) that is supplanted in Lobatchesky and Riemannian geometries.
... Anything that can be done to minimize the "z" component of this reflection, will add to the thrust.Since it is unlikely that I will have the time to re-derive Zeng and Fan's equations any time soon, please allow me to pursue this (it is much less time consuming :) )
Todd
...
In a cylinder, the longitudinal component of momentum is the wave propagating down the waveguide. The momentum is in the z direction, not radial toward the walls. In Z&F, they are depicting a waveguide, not a cavity. The momentum is propagating down the waveguide. Changing the angle > 0, changes the momentum in the z direction for a tapered waveguide, relative to a cylindrical waveguide. In the case of the wave moving toward the apex, what Z&F show is that the waves are attenuated and all of the momentum in the z direction is phase shifted and absorbed.
Essentially, attenuation of the E field in the perpendicular directions, "IS" attenuation of momentum in the r direction, because Sr = E x H perpendicular to S. The wave traveling toward the apex is losing momentum to the waveguide, in the z direction. The wave traveling toward the big end is gaining momentum in the z direction. In a cylinder, neither is true because the wave does not change momentum in either direction. So the k-vector reflecting off the wall is not (theta, phi) in Z&F, it is in the r direction. So it is r*Cos(theta) to get z direction thrust.
Todd
A cylinder is a geometrical concept. It is perfectly OK for me to speak of a cylinder as something that has open ends, it carries no implications of a being a cavity.
As to Zeng and Fan, as I said, I would have to re-derive their equations and see whether they satisfy the boundary conditions (Ricvl said that they don't) or if there is something else amiss.
For all electric field components of the spherical TE and TM modes mentioned previously, one can expressed them as... [equation 8]
... Anything that can be done to minimize the "z" component of this reflection, will add to the thrust.Since it is unlikely that I will have the time to re-derive Zeng and Fan's equations any time soon, please allow me to pursue this (it is much less time consuming :) )
Todd
1) What, specifically, can be done to minimize the "z component of the reflection at the Big End, to add to thrust?"
2) Do I understand you correctly that you think that the net force is pointing from the Big End towards the Small End? (in the opposite direction to Shawyer's thrust which he posits to be pointed from the Small End to the Big End?)
...
In a cylinder, the longitudinal component of momentum is the wave propagating down the waveguide. The momentum is in the z direction, not radial toward the walls. In Z&F, they are depicting a waveguide, not a cavity. The momentum is propagating down the waveguide. Changing the angle > 0, changes the momentum in the z direction for a tapered waveguide, relative to a cylindrical waveguide. In the case of the wave moving toward the apex, what Z&F show is that the waves are attenuated and all of the momentum in the z direction is phase shifted and absorbed.
Essentially, attenuation of the E field in the perpendicular directions, "IS" attenuation of momentum in the r direction, because Sr = E x H perpendicular to S. The wave traveling toward the apex is losing momentum to the waveguide, in the z direction. The wave traveling toward the big end is gaining momentum in the z direction. In a cylinder, neither is true because the wave does not change momentum in either direction. So the k-vector reflecting off the wall is not (theta, phi) in Z&F, it is in the r direction. So it is r*Cos(theta) to get z direction thrust.
Todd
A cylinder is a geometrical concept. It is perfectly OK for me to speak of a cylinder as something that has open ends, it carries no implications of a being a cavity.
As to Zeng and Fan, as I said, I would have to re-derive their equations and see whether they satisfy the boundary conditions (Ricvl said that they don't) or if there is something else amiss.
...
In a cylinder, the longitudinal component of momentum is the wave propagating down the waveguide. The momentum is in the z direction, not radial toward the walls. In Z&F, they are depicting a waveguide, not a cavity. The momentum is propagating down the waveguide. Changing the angle > 0, changes the momentum in the z direction for a tapered waveguide, relative to a cylindrical waveguide. In the case of the wave moving toward the apex, what Z&F show is that the waves are attenuated and all of the momentum in the z direction is phase shifted and absorbed.
Essentially, attenuation of the E field in the perpendicular directions, "IS" attenuation of momentum in the r direction, because Sr = E x H perpendicular to S. The wave traveling toward the apex is losing momentum to the waveguide, in the z direction. The wave traveling toward the big end is gaining momentum in the z direction. In a cylinder, neither is true because the wave does not change momentum in either direction. So the k-vector reflecting off the wall is not (theta, phi) in Z&F, it is in the r direction. So it is r*Cos(theta) to get z direction thrust.
Todd
A cylinder is a geometrical concept. It is perfectly OK for me to speak of a cylinder as something that has open ends, it carries no implications of a being a cavity.
As to Zeng and Fan, as I said, I would have to re-derive their equations and see whether they satisfy the boundary conditions (Ricvl said that they don't) or if there is something else amiss.
Yes Dr Rodal, to me Zeng and Fan don't write the correct expressions for the problem of propagation on a tapered conical waveguide.
One way is solve the helmoltz equations respecting directly the physical boundary conditions under the geometry of problem.
This will implies that standard solutions of wave equation in spherical coordinates ( in general, bessel and legendre functions of integer order), must be subtituted by specific solutions with fractionary order legendre/ bessel functions.
Other way, more complicated, is find solutions using the called "coupled-mode theory in instantaneous eigenmode (quasimode) basis ", where one can use a superposition cilindrical modes, evolving a coupled-mode equation along the longitudinal axis of propagation, where each cilindrical mode has a instantaneous dependence on the radii of tapered section of conical waveguide.
Of course, there are many others forms to solve this problem.
I have a real concern with TheTraveller's Excel spreadsheet. The values I get from the first basic dimensions are inconsistent. I'm talking of the file EMDriveCalc20150617b.xls available from emdrive.wiki (http://emdrive.wiki/Useful_EMDrive_Design_and_Test_Tools) as well as TT's Gdrive (https://drive.google.com/folderview?id=0B7kgKijo-p0ifk9EakZfbW9aZGMwNWZMQ01xVnBON0tkM2w0Q1NLbmtjRFFwMXBuNVlVN0U&usp=sharing#list).
Let's take know values, for example Eagleworks' frustum:
Db = 0.2794 m
Ds = 0.15875 m
Frustum length = 0.2286 m
cone half-angle = 14.78°
Input the first three values, and the spreadsheet returns a cone half-angle of 24.5° :(
Calculate the hypotenuse or draw the plan in a CAD software with the know values, you will easily get the frustum side length at 0.2364256 m. But the spreadsheet returns 0.2584848 m!
The formula for the cone half-angle (cell D8) in the spreadsheet is :
=DEGREES(ATAN((D3÷2)÷((D5×(D4÷2))+((D3÷2)−(D4÷2))+D5)))
Whereas it could use arccosine, frustum centre length (diameter center to diameter center) and frustum side length:
=DEGREES(ACOS(D5/D9)
Talking about the frustum side length (cell D9), its formula is wrong:
= SQRT(D5^2+(D3−D4)^2)
The correct formula should use end radii squared instead of end diameters squared:
= SQRT(D5^2+((D3−D4)÷2)^2)
How is the rest right or wrong? I can't even get Df right with the available spreadsheet. When inputing the Baby EmDrive data for example, Df becomes negative which is impossible (it should be comprised between 0 and 1) >:(
@TheTraveller: can you please double-check those basic values in the spreadsheet, and upload a corrected version to the emdrive.wiki? This would be much appreciated by the EmDrive community :)
Below, I show two hypothesis for TT's EmDrive Mark 2, according to how the "Frustum centre length" is defined in the spreadsheet.
- The first with Frustum centre length = 208.71 mm has a cone half-angle (corrected formula) of 30°
- The second with Frustum centre length = 240.7 mm has a cone half-angle (corrected formula) of 26.6° (instead of 27.7° with the wrong angle formula).
What is important to note is that "Frustum centre length" as defined in the spreadsheet is the length between the centers of the two end diameters, and not the length defined by TheTraveller in his drawing where it is the apex r2-r1 length. All the misunderstanding comes from the difference in that drawing (attached in third position below).
By the way those of you supporting the EM drive want an example of a theory that started out on the fringes but has gradually moved more centre wise then they only have to look at holographic theory for the universe.I honestly love this theory, simply it fits so much (but what do I know?). I've been following it for the last few months. Good post Star One!
http://www.sciencedaily.com/releases/2015/04/150427101633.htm
need it 3D :)Needs a Heat Shield......
...
In a cylinder, the longitudinal component of momentum is the wave propagating down the waveguide. The momentum is in the z direction, not radial toward the walls. In Z&F, they are depicting a waveguide, not a cavity. The momentum is propagating down the waveguide. Changing the angle > 0, changes the momentum in the z direction for a tapered waveguide, relative to a cylindrical waveguide. In the case of the wave moving toward the apex, what Z&F show is that the waves are attenuated and all of the momentum in the z direction is phase shifted and absorbed.
Essentially, attenuation of the E field in the perpendicular directions, "IS" attenuation of momentum in the r direction, because Sr = E x H perpendicular to S. The wave traveling toward the apex is losing momentum to the waveguide, in the z direction. The wave traveling toward the big end is gaining momentum in the z direction. In a cylinder, neither is true because the wave does not change momentum in either direction. So the k-vector reflecting off the wall is not (theta, phi) in Z&F, it is in the r direction. So it is r*Cos(theta) to get z direction thrust.
Todd
A cylinder is a geometrical concept. It is perfectly OK for me to speak of a cylinder as something that has open ends, it carries no implications of a being a cavity.
As to Zeng and Fan, as I said, I would have to re-derive their equations and see whether they satisfy the boundary conditions (Ricvl said that they don't) or if there is something else amiss.
Yes Dr Rodal, to me Zeng and Fan don't write the correct expressions for the problem of propagation on a tapered conical waveguide.
One way is solve the helmoltz equations respecting directly the physical boundary conditions under the geometry of problem.
This will implies that standard solutions of wave equation in spherical coordinates ( in general, bessel and legendre functions of integer order), must be subtituted by specific solutions with fractionary order legendre/ bessel functions.
Other way, more complicated, is find solutions using the called "coupled-mode theory in instantaneous eigenmode (quasimode) basis ", where one can use a superposition cilindrical modes, evolving a coupled-mode equation along the longitudinal axis of propagation, where each cilindrical mode has a instantaneous dependence on the radii of tapered section of conical waveguide.
Of course, there are many others forms to solve this problem.
I set to bold because, to my understanding, this is precisely what they did. Look at equations 2 & 3, and the associated text that follows it, through to equation 8. This part of their work is not that difficult to follow, so I don't see precisely where they make any error or assumptions that would cause it to be wrong. Their answer includes everything you just said, and the derivatives are Hankel functions of "fractional order". Where is the error?
Todd
Something has been bothering me since last night and I couldn't help but watching the modes change and flip in meep.
How can you calculate seriously any Q in a cavity that simply jumps around from one T mode decaying and building into another in such a short time? And they all do it, every simulation with varying speeds.
Just something to mull over on a day away from the shop.
Shell
Added: Back to lurk mode and I'll be quiet.
Important: normally, you should only use harminv to analyze data after the sources are off. Wrapping it in (after-sources (harminv ...)) is sufficient.
I set to bold because, to my understanding, this is precisely what they did. Look at equations 2 & 3, and the associated text that follows it, through to equation 8. This part of their work is not that difficult to follow, so I don't see precisely where they make any error or assumptions that would cause it to be wrong. Their answer includes everything you just said, and the derivatives are Hankel functions of "fractional order". Where is the error?
Todd
Not only half interger order Todd, but a real order associated legendre and bessel functions.
I need go to a party now ;D , but latter I will try explain better, but basicaly, boundary conditions under a adapted coordinate system for the problem, are satisfied only with the use of the free parameters of the general solution, and must have no dependence with the independent variables of the differential problem, or will not sove bc conditions and the differential equation simultaneously.
I opted out of a summer end party tonight mainly because Monday is a milestone birthday. Think I will celebrate with the sense that the next generation will question everything and challenge the status quo. Here's to nonconformity......
In a cylinder, the longitudinal component of momentum is the wave propagating down the waveguide. The momentum is in the z direction, not radial toward the walls. In Z&F, they are depicting a waveguide, not a cavity. The momentum is propagating down the waveguide. Changing the angle > 0, changes the momentum in the z direction for a tapered waveguide, relative to a cylindrical waveguide. In the case of the wave moving toward the apex, what Z&F show is that the waves are attenuated and all of the momentum in the z direction is phase shifted and absorbed.
Ui
Essentially, attenuation of the E field in the perpendicular directions, "IS" attenuation of momentum in the r direction, because Sr = E x H perpendicular to S. The wave traveling toward the apex is losing momentum to the waveguide, in the z direction. The wave traveling toward the big end is gaining momentum in the z direction. In a cylinder, neither is true because the wave does not change momentum in either direction. So the k-vector reflecting off the wall is not (theta, phi) in Z&F, it is in the r direction. So it is r*Cos(theta) to get z direction thrust.
Todd
A cylinder is a geometrical concept. It is perfectly OK for me to speak of a cylinder as something that has open ends, it carries no implications of a being a cavity.
As to Zeng and Fan, as I said, I would have to re-derive their equations and see whether they satisfy the boundary conditions (Ricvl said that they don't) or if there is something else amiss.
Yes Dr Rodal, to me Zeng and Fan don't write the correct expressions for the problem of propagation on a tapered conical waveguide.
One way is solve the helmoltz equations respecting directly the physical boundary conditions under the geometry of problem.
This will implies that standard solutions of wave equation in spherical coordinates ( in general, bessel and legendre functions of integer order), must be subtituted by specific solutions with fractionary order legendre/ bessel functions.
Other way, more complicated, is find solutions using the called "coupled-mode theory in instantaneous eigenmode (quasimode) basis ", where one can use a superposition cilindrical modes, evolving a coupled-mode equation along the longitudinal axis of propagation, where each cilindrical mode has a instantaneous dependence on the radii of tapered section of conical waveguide.
Of course, there are many others forms to solve this problem.
I set to bold because, to my understanding, this is precisely what they did. Look at equations 2 & 3, and the associated text that follows it, through to equation 8. This part of their work is not that difficult to follow, so I don't see precisely where they make any error or assumptions that would cause it to be wrong. Their answer includes everything you just said, and the derivatives are Hankel functions of "fractional order". Where is the error?
Todd
Not only half interger order Todd, but a real order associated legendre and bessel functions.
I need go to a party now ;D , but latter I will try explain better, but basicaly, boundary conditions under a adapted coordinate system for the problem, are satisfied only with the use of the free parameters of the general solution, and must have no dependence with the independent variables of the differential problem, or will not sove bc conditions and the differential equation simultaneously.
I love this thread and am totally addicted, can't put it down. Thanks for all the work and information! Discussions about Q, oxidation, broad / narrow spectrum and the shape of the ends have got me thinking about an alternate configuration. It has many of the same characteristics but might be slightly easier to build / find parts / work with. It is an ordinary cylinder with a cone inside. Maybe something to consider once folks are enjoying consistent thrust (lifting small objects and pets, etc... ;)
Keep up the great work!
I opted out of a summer end party tonight mainly because Monday is a milestone birthday. Think I will celebrate with the sense that the next generation will question everything and challenge the status quo. Here's to nonconformity...Todd
Something has been bothering me since last night and I couldn't help but watching the modes change and flip in meep.
How can you calculate seriously any Q in a cavity that simply jumps around from one T mode decaying and building into another in such a short time? And they all do it, every simulation with varying speeds.
Just something to mull over on a day away from the shop.
Shell
Added: Back to lurk mode and I'll be quiet.
Excellent question. I hope that you don't shy away from asking such questions because it is only this way that one can understand what is being output.
My understanding (aero to confirm) is that the quality factor is calculated by aero using the routine Harminv.
Please notice that Meep has this disclaimer for using Hamrinv to calculate the quality factor Q:
http://ab-initio.mit.edu/wiki/index.php/Meep_Reference#HarminvQuoteImportant: normally, you should only use harminv to analyze data after the sources are off. Wrapping it in (after-sources (harminv ...)) is sufficient.
Thus, the Quality factor and the frequency (also obtained by Harminv) should properly be obtained after the sources are OFF, not when they are on.
This takes us back to the whole discussion about Q quality factor in experiments. The problem is not only how to best experimentally measure and report Q, but it seems not ideal to me to discuss and report a Q (as first done by Shawyer and then imitated by all other EM Drive experimenters) with the source ON.
It seems to me that proper measurement of Q also in experiments should be done upon turning the source off and examining the decay (as posted by Frobnicat in a separate post).
With the sources OFF, the definition of Q (inverse to damping) is well-posed.
With the sources ON, the meaning of Q is tricky. It seems to me that when people are measuring Q with the sources on they are assuming a well-posed problem with "nice" properties (symmetry, etc.) that may not be fulfilled. This is particularly contradictory with TheTraveller: who rejects Finite Element solutions (using COMSOL or ANSYS) and exact solutions of the problem saying that only a solution that calculates a force can properly calculate the frequency and at the same time Shawyer "measures" Q with the RF feed ON which assumes a well posed nice solution amenable to presentation of Q as if it would be the same Q as the one calculated with the RF feed off.
The way that the Q is being measured experimentally by Shawyer and others using S11 and the 3db width is similar to a common method in structural vibration analysis. Of course, this presupposes a steady-state response. In reality with the RF feed ON, the measurement may be a transient instead.
??????????????????????????????????????????????????????????
QUESTION TO aero: have you been calculating the quality factor Q with Harminv, and if so, have you been doing so with the sources ON or OFF. Have you been wrapping with (after-sources (harminv ...)) ?
...I feel there is much more going on that meep cannot show because of some of the inherent limitations. What I'd like to see is a round tube ends capped off as a resonate chamber with a RF input, measure the Q in meep. Would you look at the CSV files from aero and do a simple compare of the Q and stress values between the two? ...Two possible ways to calculate Q from Meep, and none are possible at the moment with the output available:
Shell
Something has been bothering me since last night and I couldn't help but watching the modes change and flip in meep.
How can you calculate seriously any Q in a cavity that simply jumps around from one T mode decaying and building into another in such a short time? And they all do it, every simulation with varying speeds.
Just something to mull over on a day away from the shop.
Shell
Added: Back to lurk mode and I'll be quiet.
Excellent question. I hope that you don't shy away from asking such questions because it is only this way that one can understand what is being output.
My understanding (aero to confirm) is that the quality factor is calculated by aero using the routine Harminv.
Please notice that Meep has this disclaimer for using Hamrinv to calculate the quality factor Q:
http://ab-initio.mit.edu/wiki/index.php/Meep_Reference#HarminvQuoteImportant: normally, you should only use harminv to analyze data after the sources are off. Wrapping it in (after-sources (harminv ...)) is sufficient.
Thus, the Quality factor and the frequency (also obtained by Harminv) should properly be obtained after the sources are OFF, not when they are on.
This takes us back to the whole discussion about Q quality factor in experiments. The problem is not only how to best experimentally measure and report Q, but it seems not ideal to me to discuss and report a Q (as first done by Shawyer and then imitated by all other EM Drive experimenters) with the source ON.
It seems to me that proper measurement of Q also in experiments should be done upon turning the source off and examining the decay (as posted by Frobnicat in a separate post).
With the sources OFF, the definition of Q (inverse to damping) is well-posed.
With the sources ON, the meaning of Q is tricky. It seems to me that when people are measuring Q with the sources on they are assuming a well-posed problem with "nice" properties (symmetry, etc.) that may not be fulfilled. This is particularly contradictory with TheTraveller: who rejects Finite Element solutions (using COMSOL or ANSYS) and exact solutions of the problem saying that only a solution that calculates a force can properly calculate the frequency and at the same time Shawyer "measures" Q with the RF feed ON which assumes a well posed nice solution amenable to presentation of Q as if it would be the same Q as the one calculated with the RF feed off.
The way that the Q is being measured experimentally by Shawyer and others using S11 and the 3db width is similar to a common method in structural vibration analysis. Of course, this presupposes a steady-state response. In reality with the RF feed ON, the measurement may be a transient instead.
_______________________________________________________
QUESTION TO aero: have you been calculating the quality factor Q with Harminv, and if so, have you been doing so with the sources ON or OFF. Have you been wrapping with (after-sources (harminv ...)) ?
I love this thread and am totally addicted, can't put it down. Thanks for all the work and information! Discussions about Q, oxidation, broad / narrow spectrum and the shape of the ends have got me thinking about an alternate configuration. It has many of the same characteristics but might be slightly easier to build / find parts / work with. It is an ordinary cylinder with a cone inside. Maybe something to consider once folks are enjoying consistent thrust (lifting small objects and pets, etc... ;)
Keep up the great work!
Yes, analyse away: Data table is to wide to format nicely here, so a spread sheet is attached.So what are we seeing? Do you need for me to dig into it?
Yes, analyse away: Data table is to wide to format nicely here, so a spread sheet is attached.So what are we seeing? Do you need for me to dig into it?
I have a real concern with TheTraveller's Excel spreadsheet. The values I get from the first basic dimensions are inconsistent. I'm talking of the file EMDriveCalc20150617b.xls available from emdrive.wiki (http://emdrive.wiki/Useful_EMDrive_Design_and_Test_Tools) as well as TT's Gdrive (https://drive.google.com/folderview?id=0B7kgKijo-p0ifk9EakZfbW9aZGMwNWZMQ01xVnBON0tkM2w0Q1NLbmtjRFFwMXBuNVlVN0U&usp=sharing#list).
Let's take know values, for example Eagleworks' frustum:
Db = 0.2794 m
Ds = 0.15875 m
Frustum length = 0.2286 m
cone half-angle = 14.78°
Input the first three values, and the spreadsheet returns a cone half-angle of 24.5° :(
Calculate the hypotenuse or draw the plan in a CAD software with the know values, you will easily get the frustum side length at 0.2364256 m. But the spreadsheet returns 0.2584848 m!
The formula for the cone half-angle (cell D8) in the spreadsheet is :
=DEGREES(ATAN((D3÷2)÷((D5×(D4÷2))+((D3÷2)−(D4÷2))+D5)))
Whereas it could use arccosine, frustum centre length (diameter center to diameter center) and frustum side length:
=DEGREES(ACOS(D5/D9)
Talking about the frustum side length (cell D9), its formula is wrong:
= SQRT(D5^2+(D3−D4)^2)
The correct formula should use end radii squared instead of end diameters squared:
= SQRT(D5^2+((D3−D4)÷2)^2)
How is the rest right or wrong? I can't even get Df right with the available spreadsheet.When inputing the Baby EmDrive data for example, Df becomes negative which is impossible (it should be comprised between 0 and 1)EDIT: my mistake, 24 GHz instead of 2.4 GHz resolved this issue.
Whatever, I don't get the same Df as TheTraveller for the same untouched spreadsheet and same input values. See fourth attachement below. Those differences are quite small, but everything else following in the spreadsheet gets very different values from those discrepancies.
@TheTraveller: can you please double-check those basic values in the spreadsheet, and upload a corrected version to the emdrive.wiki? This would be much appreciated by the EmDrive community :)
Below, I show two hypothesis for TT's EmDrive Mark 2, according to how the "Frustum centre length" is defined in the spreadsheet.
- The first with Frustum centre length = 208.71 mm has a cone half-angle (corrected formula) of 30°
- The second with Frustum centre length = 240.7 mm has a cone half-angle (corrected formula) of 26.6° (instead of 27.7° with the wrong angle formula).
What is important to note is that "Frustum centre length" as defined in the spreadsheet is the length between the centers of the two end diameters, and not the length defined by TheTraveller in his drawing where it is the apex r2-r1 length. All the misunderstanding comes from the difference in that drawing (attached in third position below).
Yes, analyse away: Data table is to wide to format nicely here, so a spread sheet is attached.No wonder it's too[sic] wide. You really don't want, or need, all those significant digits.
The Eggcelerator
The Eggcelerator
Stranger things have happened. I looked at that "inverted cone" drawing and it sort of instantly generalised itself to an ovoid :)
If you really want to dive deep, look at Orbital Angular Momentum of circular radiation:
http://arxiv.org/ftp/arxiv/papers/0905/0905.0190.pdf
.. maintaining the relevant frequency to produce thrust is a severe pain. Suppose, due to something we cannot see at the moment, the frequency is impossible to maintain for whatever reason for more than a minute or two? And must be reset afterwards.I believe the reason to be purely thermal, and so it can be adjusted to remain on tune until the cows come home.
Something that has been pointed out by Rodal, Paul March, and others: maintaining the relevant frequency to produce thrust is a severe pain. Suppose, due to something we cannot see at the moment, the frequency is impossible to maintain for whatever reason for more than a minute or two? And must be reset afterwards.
.. maintaining the relevant frequency to produce thrust is a severe pain. Suppose, due to something we cannot see at the moment, the frequency is impossible to maintain for whatever reason for more than a minute or two? And must be reset afterwards.I believe the reason to be purely thermal, and so it can be adjusted to remain on tune until the cows come home.
believe the reason to be purely thermal, and so it can be adjusted to remain on tune until the cows come home.
Well, I don't subscribe to the "borrowing energy for a long time" theory. Who would?Quotebelieve the reason to be purely thermal, and so it can be adjusted to remain on tune until the cows come home.
thermal is the usual reason cited. (should have included that). But should still be confirmed.
I take it, then, apart from that, you agree with or at least do not have any major issues with the rest of my reasoning?
By the way those of you supporting the EM drive want an example of a theory that started out on the fringes but has gradually moved more centre wise then they only have to look at holographic theory for the universe.I honestly love this theory, simply it fits so much (but what do I know?). I've been following it for the last few months. Good post Star One!
http://www.sciencedaily.com/releases/2015/04/150427101633.htm
I've been kicked out of the shop while other work goes on so I've been reading way too much tech.
Shell
Well, I don't subscribe to the "borrowing energy for a long time" theory. Who would?
As for Bae, I'm still on the fence with that. I'll be staying there until I think I really understand it. Right now, I'm pretty sure I don't!
With Bae's device you get around over unity / conservation of energy via redshift and a statement that only a small fraction of each photonic bounce is used for propulsion. Yet, at the same time, another implication is missed:
For that to be true, the total energy potential of a photon would have to be many thousands of time greater than what the standard photon rocket calculations allow for. Anybody care to dispute or comment on this?
Therefor, while the calculations for maximum thrust for the classic photon rocket are correct, you HAVE to allow for the possibility of much higher thrust IF the photons greater energy can be tapped. Bae's device shows one way of doing this.
@TheTraveller: thanks, your Mark 2 drawing is consistent now. May you share the new spreadsheet on your Google Drive? Still the wrong one there.
But your cone half-angle is still wrong. Your frustum has a half-cone angle of 30.04°, not 27.7°. This is because the formula for the angle assumes the old version of Frustum centre length (Db to Ds) and not the new one (r2-r1).
Could you please share the new spreadsheet after this last correction?
Below, the confirmed version. We're finally in agreement…
...If you follow from equation 8 to 9, the expression j*kr=-(1/E)*dE/dr, is an expression for momentum in the r direction. ...I went over this reference again:
Comments?
Todd
Also that they've now built an experiment to help prove the theory to detect an effect people might have never imagined before this could have existed.I can't find any details on such an experiment. Link, please?
Another drive by Pasting.Yes, analyse away: Data table is to wide to format nicely here, so a spread sheet is attached.No wonder it's too[sic] wide. You really don't want, or need, all those significant digits.
Also that they've now built an experiment to help prove the theory to detect an effect people might have never imagined before this could have existed.I can't find any details on such an experiment. Link, please?
First look, I see a column with error on it and numbers beneath it. Why do you see it operating correctly aero? Is it because it gave Q's for those associated frequencies on the rows? What does that number in the error column mean?Yes, analyse away: Data table is to wide to format nicely here, so a spread sheet is attached.So what are we seeing? Do you need for me to dig into it?
You are seeing several cases of exactly what was described in your post above. If you want to analyse it, it is available. It tells me that the software thinks it is operating successfully, maybe it will tell you something different.
We all just See Shell. ;)
The Eggcelerator
Thanks for your eggcellent idea! Might want to run it through MEEP...JIK. It may crack interstellar flight. 8)
(Sorry couldn't resist, Good Morning!)
https://twitter.com/EggPuns/status/545618667481096193
Image: http://www.rt17.hr/teslas-egg-of-columbus/
http://arxiv.org/abs/1508.00626
The Reality of Casimir Friction
K. A. Milton, J. S. Høye, I. Brevik
Theoretical consensus is emerging.
It may be an analog of an "Electromagnetic Dean Drive" where the phenomenon may be due to the boundary conditions between the electromagnetic fields and the copper cavity instead of mechanical friction as a boundary condition between two solid surfaces. Many things point towards this:.. maintaining the relevant frequency to produce thrust is a severe pain. Suppose, due to something we cannot see at the moment, the frequency is impossible to maintain for whatever reason for more than a minute or two? And must be reset afterwards.I believe the reason to be purely thermal, and so it can be adjusted to remain on tune until the cows come home.
I would expect thermal as well to be causing the drift, mode changes into ranges that cannot be recovered from. And you can't change the input frequency when the cavity has deformed in a non-uniform way. It can be defined further to localized hot spots on the end plates, those need to be addressed... maintaining the relevant frequency to produce thrust is a severe pain. Suppose, due to something we cannot see at the moment, the frequency is impossible to maintain for whatever reason for more than a minute or two? And must be reset afterwards.I believe the reason to be purely thermal, and so it can be adjusted to remain on tune until the cows come home.
@TheTraveller:In my second generation of the Electromagnetic Reaction Drive EMD, the first adjustment is the cavity length to the input frequency (a manual lead screw) then fine tune through the transducer compensator. Very simple. Once the VSWR is set in the very first run it should remain set in this configuration.
About that triple tuning stub - am I correct in assuming that this must be operated manually, or have you come up with a motorised solution?
As a general comment - when thermal effects drive the system off tune, there are in fact two independent adjustments to be made - a frequency adjustment to find the new resonance, and an impedance adjustment to minimise VSWR.
...Is your first test EM Drive test going to have two symmetrically placed waveguides exciting the cavity or are you planing to use waveguides only in later tests? (If so, how are you going to feed the RF on your first test?)
I'm keeping the hexagonal side walls simply because it leads to a very nice way to physically mount waveguides on the 180 degree sidewalls. Should give me a solid TE012. ...
Then have it gold plated.
http://img.sookuu.com:8080/photo/10622/products/1300839663.jpg
Do the same for the small end plate.
This simple solution coupled with an active transducer feedback system in the small plate will keep the hot spots from warping the modes and changing the cavity resonance. The sidewall thermal expansion, which is a lateral down the length can be corrected by the small end transducer compensator.
So what I hope to have is a non-super conducting very high Q cavity that doesn't shift modes and frequency demands, with a long run time.
This is the first time I have disclosed this idea of the second generation ERD ... Electromagnetic Reaction Drive except to mail it to someone else a bit ago. I would love to have inputs on what everyone thinks about it.
Shell
Frequency and power stabilized magnetron 100% duty cycle
Symmetrical waveguide inputs (I hated seeing the microwaves being pushed around by the single input deforming the modes). It's as simple as the incoming wave hitting a opposing wall of the cavity and bouncing at an obscure angle or the mode being pushed by the incoming wave pressures to switch physical positions. Seen this every since our first sim with meep. The only time is when we inserted the antenna into the endplates, that was very nice.
I figure I can at least double or more the force from a cavity by stabilizing these two variables.
Shell
@TheTraveller:
About that triple tuning stub - am I correct in assuming that this must be operated manually, or have you come up with a motorised solution?
As a general comment - when thermal effects drive the system off tune, there are in fact two independent adjustments to be made - a frequency adjustment to find the new resonance, and an impedance adjustment to minimise VSWR.
The opposed waveguides are on the second revised frustum. Have the copper for it. Still working on the waveguides and ceramics and another magnetron and power supply....Is your first test EM Drive test going to have two symmetrically placed waveguides exciting the cavity or are you planing to use waveguides only in later tests? (If so, how are you going to feed the RF on your first test?)
I'm keeping the hexagonal side walls simply because it leads to a very nice way to physically mount waveguides on the 180 degree sidewalls. Should give me a solid TE012. ...
Then have it gold plated.
http://img.sookuu.com:8080/photo/10622/products/1300839663.jpg
Do the same for the small end plate.
Do you know the needed gold thickness for good resonance and high Q-factor, and if that firm can reach that requirement?This simple solution coupled with an active transducer feedback system in the small plate will keep the hot spots from warping the modes and changing the cavity resonance. The sidewall thermal expansion, which is a lateral down the length can be corrected by the small end transducer compensator.
Is this "transducer" similar to Shawyer's piezoelectric actuator (moving within a fraction of a millimeter) or is it a simpler and cheaper but slower system, like a stepper motor or a more expensive but more precise servomotor?So what I hope to have is a non-super conducting very high Q cavity that doesn't shift modes and frequency demands, with a long run time.
Does "a long run time" mean you want to make a rotary test like TheTraveller, to let the frustum accelerate?This is the first time I have disclosed this idea of the second generation ERD ... Electromagnetic Reaction Drive except to mail it to someone else a bit ago. I would love to have inputs on what everyone thinks about it.
Shell
This is exciting! :)Frequency and power stabilized magnetron 100% duty cycle
Symmetrical waveguide inputs (I hated seeing the microwaves being pushed around by the single input deforming the modes). It's as simple as the incoming wave hitting a opposing wall of the cavity and bouncing at an obscure angle or the mode being pushed by the incoming wave pressures to switch physical positions. Seen this every since our first sim with meep. The only time is when we inserted the antenna into the endplates, that was very nice.
I figure I can at least double or more the force from a cavity by stabilizing these two variables.
Shell
You could increase the force even further, as your symmetrical double-input waveguide could allow two magnetrons operating at the same time, auto-tuning each other through a slaving process known as injection locking (https://en.wikipedia.org/wiki/Injection_locking).
See this prior post by ElizabethGreene (http://forum.nasaspaceflight.com/index.php?topic=37642.msg1401433#msg1401433) in thread 3 for that matter, as well as this post by AnalogMan (http://forum.nasaspaceflight.com/index.php?topic=37642.msg1397636#msg1397636) that has a reference paper attached. As it went almost unnoticed the first time, I attach again this document: "Noise Performance of Frequency- and Phase-Locked CW Magnetrons Operated as Current-Controlled Oscillators".
So for say TE01X modes, what kind of beam is that? Is it a Gaussian beam? Or a Laguerre-Gaussian beam? Jim Beam?
In return, here's some info on resonant cavity accelerators:
http://uspas.fnal.gov/materials/09UNM/ResonantCavities.pdf (big file be patient)
Also in there is info to end the S-parameter fight from page 1.
S11 VSWR (Translated to English means measuring at input port only.) (This test should reflect conditions one would expect when the frustum is in operation so keep sample port high Z. In my test, since the sample port was "hobbled" aka just solder cup, it didn't make a difference if it was terminated, shorted, or even left open.)
S21 Measure Q via transmission method. (Input to output) (You gotta have a well matched sample port for the test. What I did after the test was "hobble" the sample port by just leaving a stubby solder cup. This was also recommended by Star-Drive. I quickly realized that since I'm interested in NOT coupling energy back out of the cavity, I had to hobble the sample port.)
It just occurred to me while I was typing all that out. I bet I could use that sample port as a way to tune the cavity somehow. Not sure how. Any ideas? Is there something I could screw onto the N-F connector which would allow me to use it as a tuner?
If you really want to dive deep, look at Orbital Angular Momentum of circular radiation:
http://arxiv.org/ftp/arxiv/papers/0905/0905.0190.pdf
3.3 Laguerre-Gaussian Beams
In order to endow our EM beam with orbital angular momentum, let us search for
a solution of the Helmholtz equation with an azimuthal e−il' dependence because,
according to Simpson et al. [46], such a beam will carry OAM. Let us use our uG
25
So for say TE01X modes, what kind of beam is that? Is it a Gaussian beam? Or a Laguerre-Gaussian beam? Jim Beam?In and out for some supplies.
In return, here's some info on resonant cavity accelerators:
http://uspas.fnal.gov/materials/09UNM/ResonantCavities.pdf (big file be patient)
Also in there is info to end the S-parameter fight from page 1.
S11 VSWR (Translated to English means measuring at input port only.) (This test should reflect conditions one would expect when the frustum is in operation so keep sample port high Z. In my test, since the sample port was "hobbled" aka just solder cup, it didn't make a difference if it was terminated, shorted, or even left open.)
S21 Measure Q via transmission method. (Input to output) (You gotta have a well matched sample port for the test. What I did after the test was "hobble" the sample port by just leaving a stubby solder cup. This was also recommended by Star-Drive. I quickly realized that since I'm interested in NOT coupling energy back out of the cavity, I had to hobble the sample port.)
TheTraveller provided this link re some Russian work on microwave thrusters:
Interesting Russian EMDrive like patent: http://bankpatentov.ru/node/123593
Wonder if that is related to this little (~0.3 m) Russian spacecraft, with no announced purpose, that was launched in May of 2014 with three other spacecraft and has apparently been scurrying around in orbit visiting some of the other payloads/booster.
http://conspiracy-cafe.blogspot.com/2015/03/kosmos-2499-is-it-spy-or-assassin-or.html
Lots of speculation as to its purpose, but, given its small size, not much speculation about how it was doing its ‘scurrying’.
I suggest along with Shawyer establish an independent international company in Cyprus with the participation of enthusiasts of new space technologies. Funding for this project can be ensured. I am ready to participate in the project.
Dr. Vladimir Leonov
...
Just to bring it back to the surface : is any one going to try with Matglas 2714A at the big end?
To see if extreme magnetic permeability has any impact on EMdrive performances?
If too expensive, a second option would be an iron plate ( as noted on the wiki list : (99.95% pure Fe annealed in H) )
Also that they've now built an experiment to help prove the theory to detect an effect people might have never imagined before this could have existed.I can't find any details on such an experiment. Link, please?
The actual experiment that will decipher this involves measuring the relative positions of large mirrors separated by 40 meters, using two Michelson laser interferometers with a precision 1 billion times smaller than an atom. If, as according to the holographic noise hypothesis, information about the positions of the two mirrors is finite, then the researchers should ultimately hit a limit in their ability to resolve their respective positions.
“What happens then?” Lanza said. “We expect to simply measure noise, as if the positions of the optics were dancing around, not able to be pinned down with more precision. So in the end, the experimental signature we are looking for is an irreducible noise floor due to the universe not actually storing more information about the positions of the mirrors.”
The team is currently collecting and analyzing data, and expects to have their first results by the end of the year. Lanza told me they are encouraged by the fact that their instruments have achieved by far the best sensitivity ever to gravitational waves at high frequencies.
“The physics of gravitational waves is unrelated to holographic noise, however, the gravity wave results demonstrate that our instrument is operating at top notch science quality, and we are now poised to experimentally dig into the science of holographic noise,” Lanza said.
The russian patent is hard to read even with automatic translation, but quite interesting :)Just to bring it back to the surface : is any one going to try with Matglas 2714A at the big end?
To see if extreme magnetic permeability has any impact on EMdrive performances?
If too expensive, a second option would be an iron plate ( as noted on the wiki list : (99.95% pure Fe annealed in H) )
This is particularly suitable for TE (transverse electric) modes, because they have a magnetic field in the axial direction. Thus it may be something that SeeShells may want to consider if she succeeds in exciting a TE mode.
TE modes ==> particularly suitable to a ferromagnetic end
TM modes ==> particularly suitable to a dielectric end (as used for example by NASA Eagleworks)
...
You have the exact solution for E and H in a frustum cavity. Simply plug in the E vector into equation 9,
kr = j*(1/E)*dE/dr
where E is the electric field vector, all 3 components, which you already have in Mathematica. I think it should be just a few lines of code to take the derivative of a vector you already have, and multiply by the inverse.
...
In a cylinder, the longitudinal component of momentum is the wave propagating down the waveguide. The momentum is in the z direction, not radial toward the walls. In Z&F, they are depicting a waveguide, not a cavity. The momentum is propagating down the waveguide. Changing the angle > 0, changes the momentum in the z direction for a tapered waveguide, relative to a cylindrical waveguide. In the case of the wave moving toward the apex, what Z&F show is that the waves are attenuated and all of the momentum in the z direction is phase shifted and absorbed.
Essentially, attenuation of the E field in the perpendicular directions, "IS" attenuation of momentum in the r direction, because Sr = E x H perpendicular to S. The wave traveling toward the apex is losing momentum to the waveguide, in the z direction. The wave traveling toward the big end is gaining momentum in the z direction. In a cylinder, neither is true because the wave does not change momentum in either direction. So the k-vector reflecting off the wall is not (theta, phi) in Z&F, it is in the r direction. So it is r*Cos(theta) to get z direction thrust.
Todd
A cylinder is a geometrical concept. It is perfectly OK for me to speak of a cylinder as something that has open ends, it carries no implications of a being a cavity.
As to Zeng and Fan, as I said, I would have to re-derive their equations and see whether they satisfy the boundary conditions (Ricvl said that they don't) or if there is something else amiss.
Yes Dr Rodal, to me Zeng and Fan don't write the correct expressions for the problem of propagation on a tapered conical waveguide.
One way is solve the helmoltz equations respecting directly the physical boundary conditions under the geometry of problem.
This will implies that standard solutions of wave equation in spherical coordinates ( in general, bessel and legendre functions of integer order), must be subtituted by specific solutions with fractionary order legendre/ bessel functions.
Other way, more complicated, is find solutions using the called "coupled-mode theory in instantaneous eigenmode (quasimode) basis ", where one can use a superposition cilindrical modes, evolving a coupled-mode equation along the longitudinal axis of propagation, where each cilindrical mode has a instantaneous dependence on the radii of tapered section of conical waveguide.
Of course, there are many others forms to solve this problem.
I set to bold because, to my understanding, this is precisely what they did. Look at equations 2 & 3, and the associated text that follows it, through to equation 8. This part of their work is not that difficult to follow, so I don't see precisely where they make any error or assumptions that would cause it to be wrong. Their answer includes everything you just said, and the derivatives are Hankel functions of "fractional order". Where is the error?
Todd
Its possible oam is the reason for force variants in different orientations. IOW cosmic speed limit might create a localized force to shed photon speed. Obviously not sure but the brick wall of C is there in our reference frame...in which we are in orbital motion...something to ponder perhaps.
If you really want to dive deep, look at Orbital Angular Momentum of circular radiation:
http://arxiv.org/ftp/arxiv/papers/0905/0905.0190.pdf
You think it is converting OAM to LM in there?
Didn't someone detect rotation in MEEP a few pages back?
http://arxiv.org/abs/1508.00626
The Reality of Casimir Friction
K. A. Milton, J. S. Høye, I. Brevik
Theoretical consensus is emerging.
Thank you for posting this reference. It would be very much appreciated any other references you may find on this subject (Casimir friction)
...
In a cylinder, the longitudinal component of momentum is the wave propagating down the waveguide. The momentum is in the z direction, not radial toward the walls. In Z&F, they are depicting a waveguide, not a cavity. The momentum is propagating down the waveguide. Changing the angle > 0, changes the momentum in the z direction for a tapered waveguide, relative to a cylindrical waveguide. In the case of the wave moving toward the apex, what Z&F show is that the waves are attenuated and all of the momentum in the z direction is phase shifted and absorbed.
Essentially, attenuation of the E field in the perpendicular directions, "IS" attenuation of momentum in the r direction, because Sr = E x H perpendicular to S. The wave traveling toward the apex is losing momentum to the waveguide, in the z direction. The wave traveling toward the big end is gaining momentum in the z direction. In a cylinder, neither is true because the wave does not change momentum in either direction. So the k-vector reflecting off the wall is not (theta, phi) in Z&F, it is in the r direction. So it is r*Cos(theta) to get z direction thrust.
Todd
A cylinder is a geometrical concept. It is perfectly OK for me to speak of a cylinder as something that has open ends, it carries no implications of a being a cavity.
As to Zeng and Fan, as I said, I would have to re-derive their equations and see whether they satisfy the boundary conditions (Ricvl said that they don't) or if there is something else amiss.
Yes Dr Rodal, to me Zeng and Fan don't write the correct expressions for the problem of propagation on a tapered conical waveguide.
One way is solve the helmoltz equations respecting directly the physical boundary conditions under the geometry of problem.
This will implies that standard solutions of wave equation in spherical coordinates ( in general, bessel and legendre functions of integer order), must be subtituted by specific solutions with fractionary order legendre/ bessel functions.
Other way, more complicated, is find solutions using the called "coupled-mode theory in instantaneous eigenmode (quasimode) basis ", where one can use a superposition cilindrical modes, evolving a coupled-mode equation along the longitudinal axis of propagation, where each cilindrical mode has a instantaneous dependence on the radii of tapered section of conical waveguide.
Of course, there are many others forms to solve this problem.
I set to bold because, to my understanding, this is precisely what they did. Look at equations 2 & 3, and the associated text that follows it, through to equation 8. This part of their work is not that difficult to follow, so I don't see precisely where they make any error or assumptions that would cause it to be wrong. Their answer includes everything you just said, and the derivatives are Hankel functions of "fractional order". Where is the error?
Todd
Sorry Todd, Dr Rodal and all people from this forum.
My fault. The zeng and fan field solutions are correct and the table 1 shows the order of associated legendre/bessel functions for some values of cone angle thetazero.
But together,the definitions in ( 8 ), (9) , (10), (11), (12), (13), and (14) make no sense to me.
A "constant" kr while defining the exponential in ( 8 ) and (9) , or in other words, kr is not a function of any spatial variable at this point, but becomes a function of r later.
The same for "constant" gamma definition in (10) and (11).
Suddenly, these "constants" becomes functions in (12), (13) and (14).
Magic?
...
Agreed, they misuse the word "constant" when pertaining to the variables, alpha and beta. It is a terminology issue though, not math that is incorrect.
It is not magic. Equation 12 is the derivative of equation 2, per equations 9 and 10, for TE modes. Equations 13 and 14 are the derivatives of equation 5, for TM modes. Since there is no component of Er in equation 2, there is no radial component of attenuation for the E field in the r direction. But there is for the TM mode, in equation 5 to give equation 14.
Todd
...
In a cylinder, the longitudinal component of momentum is the wave propagating down the waveguide. The momentum is in the z direction, not radial toward the walls. In Z&F, they are depicting a waveguide, not a cavity. The momentum is propagating down the waveguide. Changing the angle > 0, changes the momentum in the z direction for a tapered waveguide, relative to a cylindrical waveguide. In the case of the wave moving toward the apex, what Z&F show is that the waves are attenuated and all of the momentum in the z direction is phase shifted and absorbed.
Essentially, attenuation of the E field in the perpendicular directions, "IS" attenuation of momentum in the r direction, because Sr = E x H perpendicular to S. The wave traveling toward the apex is losing momentum to the waveguide, in the z direction. The wave traveling toward the big end is gaining momentum in the z direction. In a cylinder, neither is true because the wave does not change momentum in either direction. So the k-vector reflecting off the wall is not (theta, phi) in Z&F, it is in the r direction. So it is r*Cos(theta) to get z direction thrust.
Todd
A cylinder is a geometrical concept. It is perfectly OK for me to speak of a cylinder as something that has open ends, it carries no implications of a being a cavity.
As to Zeng and Fan, as I said, I would have to re-derive their equations and see whether they satisfy the boundary conditions (Ricvl said that they don't) or if there is something else amiss.
Yes Dr Rodal, to me Zeng and Fan don't write the correct expressions for the problem of propagation on a tapered conical waveguide.
One way is solve the helmoltz equations respecting directly the physical boundary conditions under the geometry of problem.
This will implies that standard solutions of wave equation in spherical coordinates ( in general, bessel and legendre functions of integer order), must be subtituted by specific solutions with fractionary order legendre/ bessel functions.
Other way, more complicated, is find solutions using the called "coupled-mode theory in instantaneous eigenmode (quasimode) basis ", where one can use a superposition cilindrical modes, evolving a coupled-mode equation along the longitudinal axis of propagation, where each cilindrical mode has a instantaneous dependence on the radii of tapered section of conical waveguide.
Of course, there are many others forms to solve this problem.
I set to bold because, to my understanding, this is precisely what they did. Look at equations 2 & 3, and the associated text that follows it, through to equation 8. This part of their work is not that difficult to follow, so I don't see precisely where they make any error or assumptions that would cause it to be wrong. Their answer includes everything you just said, and the derivatives are Hankel functions of "fractional order". Where is the error?
Todd
Sorry Todd, Dr Rodal and all people from this forum.
My fault. The zeng and fan field solutions are correct and the table 1 shows the order of associated legendre/bessel functions for some values of cone angle thetazero.
But together,the definitions in ( 8 ), (9) , (10), (11), (12), (13), and (14) make no sense to me.
A "constant" kr while defining the exponential in ( 8 ) and (9) , or in other words, kr is not a function of any spatial variable at this point, but becomes a function of r later.
The same for "constant" gamma definition in (10) and (11).
Suddenly, these "constants" becomes functions in (12), (13) and (14).
Magic?
Agreed, they misuse the word "constant" when pertaining to the variables, alpha and beta. It is a terminology issue though, not math that is incorrect.
It is not magic. Equation 12 is the derivative of equation 2, per equations 9 and 10, for TE modes. Equations 13 and 14 are the derivatives of equation 5, for TM modes. Since there is no component of Er in equation 2, there is no radial component of attenuation for the E field in the r direction. But there is for the TM mode, in equation 5 to give equation 14.
Todd
...Yes, basically γ = γ (r) hence it does not make sense that γ is treated as a constant to define
If one has a function with exponential format F=exp(k.x) and k is a constant then one can write k=(dF/dx)/F.
But if one has a function F=exp(k(x).x) then (dF/dx)/F=k(x) + xdk(x)/dx
If F has no exponential format is worse.
The wave solutions in spherical coodinates are the form exp(+ik.r)/r and exp(-ik.r)/r only when r goes to infinity.
...Yes, basically γ = γ (r) hence it does not make sense that γ is treated as a constant to define
If one has a function with exponential format F=exp(k.x) and k is a constant then one can write k=(dF/dx)/F.
But if one has a function F=exp(k(x).x) then (dF/dx)/F=k(x) + xdk(x)/dx
If F has no exponential format is worse.
The wave solutions in spherical coodinates are the form exp(+ik.r)/r and exp(-ik.r)/r only when r goes to infinity.
E = A e - γ r
γ = - (1/E) dE/dr = α + j β
because this is only true for γ = constant
...Yes, basically γ = γ (r) hence it does not make sense that γ is treated as a constant to define
If one has a function with exponential format F=exp(k.x) and k is a constant then one can write k=(dF/dx)/F.
But if one has a function F=exp(k(x).x) then (dF/dx)/F=k(x) + xdk(x)/dx
If F has no exponential format is worse.
The wave solutions in spherical coodinates are the form exp(+ik.r)/r and exp(-ik.r)/r only when r goes to infinity.
E = A e - γ r
γ = - (1/E) dE/dr = α + j β
because this is only true for γ = constant
So, really
- (1/E) dE/dr = γ + r dγ/dr
So Zeng and Fan's expression is exact when dγ/dr = 0, that is when γ is constant.
and approximate for dγ/dr ~ 0 (γ nearly constant)
so in the images shown in http://forum.nasaspaceflight.com/index.php?topic=38203.msg1414705#msg1414705 above and in Zeng and Fan's figures, the γ expression is more accurate as a measure of attenuation where γ is flat (where the gradient dγ/dr ~ 0 ) and nearly constant, which is more nearly the case for values such that:
γ = 0 (NO ATTENUATION)
...Yes I realize that. There is no harm in showing it simply as -(1/E)dE/dr without the meaning attached by Zeng and Fan, to understand what -(1/E)dE/dr looks like.
Gamma = alfa (attenuation) + jbeta (propagation)
No attenuation = zero alfa
Becareful. The expression for gamma do not make sense for stationary waves ( two counter propagating waves and, of course, with diferent gammas)
Pedantically it's the gradient of the log of the field, rather than the log of the gradient
Interesting reddit link... https://neolegesmotus.wordpress.com
Seems like a similar senario to spr, tho design is different. Italian non newtonian propulsion company. Hmmmmm
You've got me doc...not a company logo...decoration apparently.Interesting reddit link... https://neolegesmotus.wordpress.com
Seems like a similar senario to spr, tho design is different. Italian non newtonian propulsion company. Hmmmmm
What's up with the Iron Cross on it ?
and the inscription on it reading:You've got me doc...not a company logo...decoration apparently.Interesting reddit link... https://neolegesmotus.wordpress.com
Seems like a similar senario to spr, tho design is different. Italian non newtonian propulsion company. Hmmmmm
What's up with the Iron Cross on it ?
Thks, my italian is lame. strange thing to put on something someone wants to solicit funding for. Guess they're religious minded...and the inscription on it reading:You've got me doc...not a company logo...decoration apparently.Interesting reddit link... https://neolegesmotus.wordpress.com
Seems like a similar senario to spr, tho design is different. Italian non newtonian propulsion company. Hmmmmm
What's up with the Iron Cross on it ?
"Fear of the Lord"
and the inscription on it reading:You've got me doc...not a company logo...decoration apparently.Interesting reddit link... https://neolegesmotus.wordpress.com
Seems like a similar senario to spr, tho design is different. Italian non newtonian propulsion company. Hmmmmm
What's up with the Iron Cross on it ?
"Fear of the Lord"
Last but not least, when functioning PNN-E produces massive E.M radiation, so who works in proximity of the prototype must wear a protective suit. Laureti found a curious but effective solution: he modified a medieval chain mail to work as a Faraday cage.
Seems like a similar scenario to SPR, though the design is different. Italian non Newtonian propulsion company. Hmmmmm
Has the article "Resonant cavities and space-time thrust" from Marco Frasca been discussed on this forum ? A quick search on "frasca" keyword gave no result.
This article, dated May 20, 2015, analyses, by solving Einstein field equations, the geometry of space-time in a cavity when a plane electromagnetic wave is present. Influence of cavity shape is also considered.
It looks a pretty serious work ... but I am not operational enough in General Relativity to make a deep referee of it.
I can understand the attraction of taking the idea of Casimir friction in order to explain an EmDrive as some sort of Zero-Point Dean Drive. A pawl and ratchet into spacetime. What I don't understand is how people can make such a proposal when there is no Casimir effect in an EmDrive in the first place.
http://forum.nasaspaceflight.com/index.php?topic=37642.msg1378648#msg1378648
and the inscription on it reading:You've got me doc...not a company logo...decoration apparently.Interesting reddit link... https://neolegesmotus.wordpress.com
Seems like a similar senario to spr, tho design is different. Italian non newtonian propulsion company. Hmmmmm
What's up with the Iron Cross on it ?
"Fear of the Lord"
The symbol is a "Cross Pattee" often associated with the Knights Templar. The Iron Cross has a different shape. See: https://en.m.wikipedia.org/wiki/Cross_pattée
Last but not least, when functioning PNN-E produces massive E.M radiation, so who works in proximity of the prototype must wear a protective suit. Laureti found a curious but effective solution: he modified a medieval chain mail to work as a Faraday cage.
However, while testing PNN-E and in particular TDS VF2, ASPS discovered that the thruster doesn’t follow the common law of inertia, because E.M propulsion literally “accelerates on its own acceleration”. Hence there is the need for ASPS to define a totally new law of inertia that would allow an E.M starship to cover several light years in few seconds! It sounds astonishing but ASPS seems confident in theory effectiveness.
http://forum.nasaspaceflight.com/index.php?topic=37642.msg1378648#msg1378648
Thank you for the link. So Marco Fresca is still working to improve his paper and will publish it on arxiv when ready with numerical results on the predicted thrust (apparently this day is not yet arrived).
No, the message linked by TheTraveller is just an old message, one of several messages posted by the author.http://forum.nasaspaceflight.com/index.php?topic=37642.msg1378648#msg1378648
Thank you for the link.
So Marco Fresca is still working to improve his paper and will publish it on arxiv when ready with numerical results on the predicted thrust (apparently this day is not yet arrived).
Off topic alert - Today, I turned the big six-zero; a milestone birthday. Which should be used to convince others that one can still think, dream and build well into their senior era. So many companies and institutions look to replace older folks once they turn 50...I know from experience. I also know that its a waste of talent to do this.
So, here's to the older generation still plugging away at science. How I wish something like this project were around when I was much younger. THAT should be a message to the young folks out there to get involved in science early. Push the envelope, think outside the box, do something different...who knows, what you may come up with could change the world.
Onward and upward - Dave (rfmwguy)
No, the message linked by TheTraveller is just an old message, one of several messages posted by the author.
Marco's paper has already been published in Arxiv and ResearchGate some time ago. We discussed Marco's paper in detail with him prior to publication. We discussed limits of expressions, the perturbation approach and numerical results. The conclusion was that General Relativity could not be used to justify the claimed thrust for the EM Drive because the GR effect discussed by Frasca happens very close to the singularity at the vertex of the cone (as it is evident from his paper). Shawyer by intentional design on his part (claiming a waveguide cut-off effect on the small diameter although there is no such cut-off for tapered waveguides) stopped the EM Drive geometry very far away from the vertex of the cone, hence the effect discussed by Frasca is several orders of magnitude much smaller that what is claimed as thrust by EM Drive researchers.
Frobnicat, that smiley was perfect. Definitely a WTF moment.LOL...yep :o was perfect. Funny how people jump to extreme applications without due-diligence on prototypes...i.e. replication, explanation and 3rd party verification. That leads to speculation on whether its all a funding scheme.
Off topic alert - Today, I turned the big six-zero; a milestone birthday. Which should be used to convince others that one can still think, dream and build well into their senior era. So many companies and institutions look to replace older folks once they turn 50...I know from experience. I also know that its a waste of talent to do this.And a very happy birthday from another of the older generation. As my mom said to me many times Dave. Make it so!
So, here's to the older generation still plugging away at science. How I wish something like this project were around when I was much younger. THAT should be a message to the young folks out there to get involved in science early. Push the envelope, think outside the box, do something different...who knows, what you may come up with could change the world.
Onward and upward - Dave (rfmwguy)
I was asking myself how long it would take to empty the frustum of the energy stored, now I know, not long :)Perfect! Was looking this morning at how much the mode changes could kill off the Q and the time frame needed. Thanks
Extracting microwave energy from a cavity by mode conversion at a coupling window
http://rd.springer.com/article/10.1134/1.1259080
"It is shown that microwave rf pulse compressors with copper storage cavities and energy extraction by mode conversion at a coupling window can provide gains of 5–13 dB with output signal durations of 20–150 ns and peak powers of 5–10 MW in the 3-cm band and 50–100 MW in the 10-cm band. "
Has anyone, in the thousands of posts here, calculated how much water (gm/s) it would take to generate X N of thrust by evaporation and steam jetting?
Off topic alert - Today, I turned the big six-zero; a milestone birthday. Which should be used to convince others that one can still think, dream and build well into their senior era. So many companies and institutions look to replace older folks once they turn 50...I know from experience. I also know that its a waste of talent to do this.
So, here's to the older generation still plugging away at science. How I wish something like this project were around when I was much younger. THAT should be a message to the young folks out there to get involved in science early. Push the envelope, think outside the box, do something different...who knows, what you may come up with could change the world.
Onward and upward - Dave (rfmwguy)
Hi Thor,
No, 30% is the amount of time power is at 100%, so it will "pulse" at full power for 30% of the time.
Hi Thor,
No, 30% is the amount of time power is at 100%, so it will "pulse" at full power for 30% of the time.
Sorry, busy weekend! Happy birthday!
Ok, right. That's makes the spreadsheet spit out (assuming 64% efficiency in converting electrical input into RF) a figure of up to 100.93mN or 144.71 mN for 30% of the time.
I took a break today and let my computer run 64 cycles of the Shell conic frustum cavity model. The png views and csv data of the final 14 time slices is available here. To me, it does look to be much more "converged" than 32 cycle runs.
https://drive.google.com/folderview?id=0B1XizxEfB23tfmVCZlhnNUVtTGRoTTlZSGJiT3ZfSHBvYnNELUc1WlN0Sk15ZDZud3pSWmM&usp=sharing (https://drive.google.com/folderview?id=0B1XizxEfB23tfmVCZlhnNUVtTGRoTTlZSGJiT3ZfSHBvYnNELUc1WlN0Sk15ZDZud3pSWmM&usp=sharing)
Please read the data description file for the details of the run.
Nice work aero. I like this and your run file is very easy to read.
I organized the images in a equal grid http://i.imgur.com/0S3xpKH.jpg
My question is, are the vertical columns when arranged like this showing the same time stamp through the frustum for the sample on the waveform showing the mode?
Shell
First column
ex.t00
ey.t00
ez.000
etc....I took a break today and let my computer run 64 cycles of the Shell conic frustum cavity model. The png views and csv data of the final 14 time slices is available here. To me, it does look to be much more "converged" than 32 cycle runs.
https://drive.google.com/folderview?id=0B1XizxEfB23tfmVCZlhnNUVtTGRoTTlZSGJiT3ZfSHBvYnNELUc1WlN0Sk15ZDZud3pSWmM&usp=sharing (https://drive.google.com/folderview?id=0B1XizxEfB23tfmVCZlhnNUVtTGRoTTlZSGJiT3ZfSHBvYnNELUc1WlN0Sk15ZDZud3pSWmM&usp=sharing)
Please read the data description file for the details of the run.
Please notice that McCulloch's formula is completely unable to distinguish between TM (transverse magnetic) from TE (transverse electric) modes. Actually McCulloch's formula completely ignores the mode shape (it ignores not only whether TE or TM but also it ignores the quantum mode shape numbers m,n,p). This is a weakness in McCulloch's formula (not present in Notsosureofit's formula that does take into account the mode shapes).
Those claiming much larger thrust and thrust/InputPower claim to use TE modes: Shawyer and Yang.
NASA also reported much larger thrust/InputPower when using TE modes but could not excite it consistently so they switched to TM modes.
So, there is considerable uncertainty when predicting thrust with a formula that ignores the mode shape of EM Drive operation.
Frobnicat, that smiley was perfect. Definitely a WTF moment.LOL...yep :o was perfect. Funny how people jump to extreme applications without due-diligence on prototypes...i.e. replication, explanation and 3rd party verification. That leads to speculation on whether its all a funding scheme.
On NSF-1701, if I've detected any force whatsoever, I'll try and figure out why only to a point. After that, I would prefer to offer it (for free) to a reputable institution that is willing to duplicate tests under (expensive) laboratory conditions.
Of course, if they break it...that would spoil my day ;)
Please notice that McCulloch's formula is completely unable to distinguish between TM (transverse magnetic) from TE (transverse electric) modes. Actually McCulloch's formula completely ignores the mode shape (it ignores not only whether TE or TM but also it ignores the quantum mode shape numbers m,n,p). This is a weakness in McCulloch's formula (not present in Notsosureofit's formula that does take into account the mode shapes).
Those claiming much larger thrust and thrust/InputPower claim to use TE modes: Shawyer and Yang.
NASA also reported much larger thrust/InputPower when using TE modes but could not excite it consistently so they switched to TM modes.
So, there is considerable uncertainty when predicting thrust with a formula that ignores the mode shape of EM Drive operation.
The derivation (F = 6PQL/c * [1/(L+4wb) - 1/(L+4ws) ] which I found on http://physicsfromtheedge.blogspot.co.uk/2015/02/mihsc-vs-emdrive-data-3d.html) that I'm using in my spreadsheet doesn't take into account the input frequency of the radiation either, just the Power and the "Q".
EDIT: If I get a chance tonight I'll try to add Notsosureofit's formula to my spreadsheet and see what happens
Interesting Russian EMDrive like patent:
http://bankpatentov.ru/node/123593
and comment received on Reddit EMDrive forum:
https://www.reddit.com/r/EmDrive/comments/3ceyjv/email_from_roger_shawyer/ctww6rd
As Dr. Vladimir Leonov claims the "Shawyer Effect" works via the QV, Dr. White might be interested.
Off topic alert - Today, I turned the big six-zero; a milestone birthday. Which should be used to convince others that one can still think, dream and build well into their senior era. So many companies and institutions look to replace older folks once they turn 50...I know from experience. I also know that its a waste of talent to do this.
So, here's to the older generation still plugging away at science. How I wish something like this project were around when I was much younger. THAT should be a message to the young folks out there to get involved in science early. Push the envelope, think outside the box, do something different...who knows, what you may come up with could change the world.
Onward and upward - Dave (rfmwguy)
Just think of it, Dave: Donald Trump is over 69 years old, so you have more than 9 years left for you to run for President of the US :)
https://drive.google.com/folderview?id=0B1XizxEfB23tfmVCZlhnNUVtTGRoTTlZSGJiT3ZfSHBvYnNELUc1WlN0Sk15ZDZud3pSWmM&usp=sharingSince the mode shapes are shown on different scales, without showing the numbers, a mode shape that has magnitude that is dozens or hundreds of times smaller amplitude (and thus insignficant) looks significant when compared without numbers. Hence the images are very difficult to understand .
I took both Center x and Center Y pages and opened them into separate folders, sized them so one row was 14 images across and the vertical columns were synced 00, 01, 02, 03, 04... same time slice. Then switched back and forth between the pages comparing a image and mode for X to Y and at the same position.
In some cases the modes match X and Y but several they don't even come close. Just another flag of an interesting anomaly of how you could see in a relatively symmetrical cavity mode variation just between a X slice through the middle and a Y slice through the middle in the same time stamp.
Or has everyone seen this weirdness and you're going to go... phhhsst, silly old woman...
Shell
Happy birthday rfmwguy :)Danke, herr x_ray!
Thanks, Doc...you cheered me up enough that I feel like this ;)Off topic alert - Today, I turned the big six-zero; a milestone birthday. Which should be used to convince others that one can still think, dream and build well into their senior era. So many companies and institutions look to replace older folks once they turn 50...I know from experience. I also know that its a waste of talent to do this.
So, here's to the older generation still plugging away at science. How I wish something like this project were around when I was much younger. THAT should be a message to the young folks out there to get involved in science early. Push the envelope, think outside the box, do something different...who knows, what you may come up with could change the world.
Onward and upward - Dave (rfmwguy)
Just think of it, Dave: Donald Trump is over 69 years old, so you have more than 9 years left for you to run for President of the US :)
Happy birthday rfmwguy :)Danke, herr x_ray!
I will have a live session the day before I run the actual live test, basically walking throught the setup. This should be 2 weeks or less and hope to announce it next week sometime.Happy birthday rfmwguy :)Danke, herr x_ray!
Is it possible to record your next live run?
I have little problems with the time difference between our countries, last time i was sleeping, dont see your live show :-[
Did you see this file?
There is a description for possible Q measurement with only one port.
The problem with a magnetron is that is only a source, there is no IQ mixer (or six port) inside the magnetron... So it may be the simplest way is to use a probe port in that case.
http://uspas.fnal.gov/materials/09UNM/ResonantCavities.pdf (big file be patient)
Thanks Mulletron for post the link
BTW: I hope you got a great party today! :P
@rfmwguy: Happy Birthday!Thks dm...I was going to use battery until the junk exciter spoiled my day. It was only going to put out about 8 watts after amplification...far too low power for me to be able to measure on the Floobie Stick balance beam...so, the magnetron was chosen.
About that spendy Galinstan: did you at least consider a fully-self-contained rig using batteries? - and what put you off it?
For Shawyer to try and patent this before there was even a dream of a viable commercial product is ludicrous.
He should have opened it up to research at the beginning.He did. He's been writing about it publicly for a decade to anyone who would listen. For his trouble he's been called a fraud and charlatan. He's been mocked and ridiculed. To imply that he's hoarded this to himself is a particularly bitter insult.
Based on what I know, the current iteration is obviously not viable.Your knowledge is incorrect. He discovered the Shawyer effect and then spent years inventing, experimenting, and refining devices that generated thrust from RF energy. The device accomplished the "impossible". That certainly seems "viable" to me.
If members of the public are able to own a personal stake in something as evolutionary as this, some will gladly invest enormous amounts of effort, even with no guarantee of any financial reward or any success; like us.Mr. Shawyer built this technology "with no guarantee of any financial reward or any success." How is his contribution somehow inferior to what we would create?
So can it be done? Should it be done? If so, we need help...
We just have to make it roll. The rest is history.
I call it "ballooning" when the cavity is perfectly airtight and the walls bulge slightly - the thinner the walls, the greater this effect. Due to the increase in external volume at constant contained mass, the cavity density decreases and thus experiences increased buoyancy in air. There is however a counter-effect present; because the air around the cavity is also heated, it enjoys a lower density, which in turn reduces this buoyancy. Which of these two competing effects wins out depends on all the details.This thought was based on inelastic walls who are thick enough..
When the cavity is not airtight, there are two effects to be expected:
a) a loss of all-up cavity mass due to the mass of the expelled air with increased heating
b) the possibility of a rocket effect due to convection of cavity gas in a preferred direction, which in turn depends on where it's leaking. Note that, for certain leakage patterns, one would see the artifact of reversed thrust when the cavity is flipped, since now the "jet" direction is also flipped.
Note that, in vacuum, none of the above occur if care is taken to evacuate the cavity.
@rfmwguy: Happy Birthday!
About that spendy Galinstan: did you at least consider a fully-self-contained rig using batteries? - and what put you off it?
https://drive.google.com/folderview?id=0B1XizxEfB23tfmVCZlhnNUVtTGRoTTlZSGJiT3ZfSHBvYnNELUc1WlN0Sk15ZDZud3pSWmM&usp=sharingSince the mode shapes are shown on different scales, without showing the numbers, a mode shape that has magnitude that is dozens or hundreds of times smaller amplitude (and thus insignficant) looks significant when compared without numbers. Hence the images are very difficult to understand .
I took both Center x and Center Y pages and opened them into separate folders, sized them so one row was 14 images across and the vertical columns were synced 00, 01, 02, 03, 04... same time slice. Then switched back and forth between the pages comparing a image and mode for X to Y and at the same position.
In some cases the modes match X and Y but several they don't even come close. Just another flag of an interesting anomaly of how you could see in a relatively symmetrical cavity mode variation just between a X slice through the middle and a Y slice through the middle in the same time stamp.
Or has everyone seen this weirdness and you're going to go... phhhsst, silly old woman...
Shell
Remember how we progressed:
1) At the beginning of MEEP runs, the same fields were shown on different scales from time step to time step. It looked so crazy that even the field outside the EM Drive had flashing colors. And inside the EM Drive we could see fractals that were numerical artifacts.
This was fixed by showing all the time steps at the same final scale. This fixed the fractals and the crazy colors outside the EM Drive.
2) We still have the problem that different fields in different directions: Ex, Ey, Ez, Hx, Hy, and Hz, are shown with different scales. Thus one is not able to distinguish, say if E in the x direction is 1000 times less than E in the y direction. Thus we cannot distinguish "noise" from signal.
ALL electric fields should be shown on the same scale and all magnetic fields should be shown to the same scale. Otherwise there is no comprehension.
3) I cannot tell what the mode shape being excited is, from looking at these images: is it TE ? is it TM? nobody knows. Why is it that nobody knows? Because the fields are not shown to the same scale, thus nobody can tell whether it is TE or TM. We don't know what is noise and what is signal.
Is the field in the longitudinal z direction an electric field (and hence a TM mode) or is it a magnetic field (and thus a TE mode). We cannot tell, both mode shapes are being shown and we don't know which is large and which is negligible.
If they would be shown to the same scale, and one mode shape happens to be 100 times smaller magnitude than another one, it would look like zero, and we would not look at it, thus we would better understand because we would be looking ONLY at the mode shapes that are high in magnitude. The way it is now, we don't know what is high magnitude and what is low magnitude.
Imagine what life would be like if your senses would be such that we would not be able to distinguish between what is near and what is far, between what is high and what is low, we would be lost.
...The numbers are in the csv files, but it is much more time consuming to post-process the csv files than to just click and look at the images. All my 3 computers are otherwise occupied at the moment. I had a small window of time in one computer which I used to calculate something that Todd will be interested in :) Hope to get to this soon.
Sigh. Lost? No, just regroup.
Thanks for the recap, I did't realize we handicapped the visual data as much as we did in truncating data simply making it unusable as a visual aid.
I hope the numbers haven't been truncated in the CSV files as well. Back to lurk and dig.
Shell
...
Agreed, they misuse the word "constant" when pertaining to the variables, alpha and beta. It is a terminology issue though, not math that is incorrect.
It is not magic. Equation 12 is the derivative of equation 2, per equations 9 and 10, for TE modes. Equations 13 and 14 are the derivatives of equation 5, for TM modes. Since there is no component of Er in equation 2, there is no radial component of attenuation for the E field in the r direction. But there is for the TM mode, in equation 5 to give equation 14.
Todd
It may be interesting to plot the γ function, the logarithmic gradient of the electric field:
γ = - dLog[E]/dr = - (1/E)*dE/dr
defined by Zeng and Fan, and apply it to the case of standing waves in a closed resonant cavity: Yang/Shell for TE011 and TE012, to see what it looks like.
In this case γ = γθ = γφ
γθ = - (1/Eθ)*dEθ/dr = γφ = - (1/Eφ)*dEφ/dr
γ is real, these are standing waves hence there is no imaginary component of γ.
γ grows without bounds, to Infinity, at each end because the transverse electric fields are zero at the big base and at the small base in order to satisfy the boundary condition that electric fields parallel to a metal boundary must be zero. Since γ is defined as the ratio of the gradient of the electric field with respect to r, divided by the electric field, when the field is zero at the bases, while the numerator is maximum, γ is infinite at the boundaries.
For TE012, γ also grows without bounds at the middle node of the two half-wave patterns because at that point the transverse electric field is zero while its gradient with respect to r is maximum.
Notice that γ is negative at the small base (small r) and positive at the big base (large r).
...Yes, basically γ = γ (r) hence it does not make sense that γ is treated as a constant to define
If one has a function with exponential format F=exp(k.x) and k is a constant then one can write k=(dF/dx)/F.
But if one has a function F=exp(k(x).x) then (dF/dx)/F=k(x) + xdk(x)/dx
If F has no exponential format is worse.
The wave solutions in spherical coodinates are the form exp(+ik.r)/r and exp(-ik.r)/r only when r goes to infinity.
E = A e - γ r
γ = - (1/E) dE/dr = α + j β
because this is only true for γ = constant
So, really
- (1/E) dE/dr = γ + r dγ/dr
So Zeng and Fan's expression is exact when dγ/dr = 0, that is when γ is constant.
and approximate for dγ/dr ~ 0 (γ nearly constant)
so in the images shown in http://forum.nasaspaceflight.com/index.php?topic=38203.msg1414705#msg1414705 above and in Zeng and Fan's figures, the γ expression is more accurate as a measure of attenuation where γ is flat (where the gradient dγ/dr ~ 0 ) and nearly constant, which is more nearly the case for values such that:
γ = 0 (NO ATTENUATION)
...The numbers are in the csv files, but it is much more time consuming to post-process the csv files than to just click and look at the images. All my 3 computers are otherwise occupied at the moment. I had a small window of time in one computer which I used to calculate something that Todd will be interested in :) Hope to get to this soon.
Sigh. Lost? No, just regroup.
Thanks for the recap, I did't realize we handicapped the visual data as much as we did in truncating data simply making it unusable as a visual aid.
I hope the numbers haven't been truncated in the CSV files as well. Back to lurk and dig.
Shell
It is thanks to aero running Meep that we are able to calculate and show:I also am very glad aero is here doing work that has effectively moved this group forward with answers garnered in meep that simply were not available to the group in any other fashion. And with your help we got some very good answers.
1) The huge difference between having RF feed ON with travelling waves vs. the case examined by Greg Egan (RF feed OFF with standing waves)
2) The fact that there is Poynting vector directionally oriented with the RF feed ON that keeps growing with time exponentially, with the RF Feed on.
3) The fact that the stresses and hence the forces at the small and big bases are greatly influenced by the antenna with the RF feed ON
4) The difference between placing the antenna at the small end vs the big end
5) The difference between placing the antenna at the axis of axi-symmetry vs being offset
6) The difficulties of exciting TE modes with dipole antennas
I say no, nobody here is overloaded, rfmwguy and SeeShells can carry much more on their shoulders, so aero, keep it going with
7) Loop antennas to excite TE modes
8 ) Showing what happens when your turn the RF feed OFF
9) Modeling a waveguide entering the cavity to excite a TE mode in the cavity
10) Showing how steady-state is approached
etc.
:)
...Perhaps aero (or somebody else) will find a way to:
I also am very glad aero is here doing work that has effectively moved this group forward with answers garnered in meep that simply were not available to the group in any other fashion. And with your help we got some very good answers.
But a couple of questions arise in how we can accomplish this with the data being displayed as it currently is.
How can we even know that a TM mode can be excited when you declared that the displayed modes were of little value after the filtering of the data files to rid the display of the artifacts and flashing colors. The only way I can see is not to be dependent on the display of meep and post-process but use another program, Wolfram or something else?
I need to know how to forecast the future use of meep and post processing because this second build I'll be going after building a stable frustum with ceramic gold plated endplates and an active feedback system to assure mode and frequency lock. If I can't get the answers here than I'll need to take a longer path.
I was busy today tracking down and talking with old contacts that are going to try to get me the ceramics for the endplates. I'll need to tell them before too long what size I want them to be. The final shape of the ERD frustum will depend on how well meep and post processing can show what shape is optimal for it. For that we need as stable of an answer we can get. Simply for keeping a TE mode in a stabilized frustum, I think this is needed.
Shell
.........
Thanks to our "NSF Peer Review Committee" with members Ricvl, Todd "WarpTech" and yours truly we have peer-reviewed Zeng and Fan's paper better than was done by the original editiorial review by Optics Express Journal:
Electromagnetic fields and transmission properties in tapered hollow metallic waveguides
Xiahui Zeng and Dianyuan Fan
https://www.osapublishing.org/oe/fulltext.cfm?uri=oe-17-1-34&id=175583
Ricvl uncovered the important error that Zeng and Fan failed to properly derive the γ exponent, as they improperly considered it to be a constant in the initial part of their derivation and then a posteriori they inconsistently considered it to be a function of r.
I have properly solved the first order differential equation for γ(r):
r dγ/dr + γ = - (1/Eθ)*dEθ/dr
that arises from solving for the exponent γ in the following expression:
Eθ = A e - γ r
(observe that Zeng and Fan did not solve this equation, instead they considered r dγ/dr << γ and hence assumed
γ = - (1/Eθ)*dEθ/dr).
When properly solving the differential equation (numerically, since it does not have a closed form solution, and it is quite difficult to solve numerically because it contains highly oscillating functions and it diverges at the boundaries)
I get the enclosed attenuation curve for γ for Yang/Shell in TE011 mode, with the RF feed off, standing waves, which does make sense (the solution based on Zeng & Fan's equation γ = - (1/Eθ)*dEθ/dr does not make sense because it contains a large geometrical magnification at the small end).
The attenuation is positive over the whole EM Drive, being close to zero over most of it but diverging to high attenuation at both ends because (1/Eθ)*dEθ/dr) diverges at the ends as previously explained due to the fact that the electric field Eθ must be zero at the bases. Therefore the tangent electric field Eθ gets 100% attenuated at the small base and at the big base. The attenuation curve for the other tangent electric field Eφ is identical.
Notice the asymmetry: there is more attenuation going on towards the small base.
Thus we have properly solved this problem for the case in which Eθ satisfies the bondary conditions for a resonant cavity.
Recall
...
Dr Rodal, I think there is a problem again.
Standing waves.
In the cavity, at least, the fields are superpositions of two counter propagating waves, then one has (to simplify)
E=[a.exp(gamma.r)+b.exp(-gamma.r)].F(tetha,phi)
Repair, the expression above is just a aproximate model to fit the fields by exponential functions, where the correct is to use fractional spherical hankel functions (for spherical ends cavitys), where a,b and gamma will fataly be functions of r. At r>>1 the spherical hankel function decay with 1/r.
Then how to differentiate a destructive interference at node fields from a infinity attenuation?
Worse, even with a,b and gamma being constants, when one take the derivative of E above, because the two signals of gamma (outward/inward from/to apex cone) one has
dE/dr=gamma[a.exp(gamma.r) -b.exp(-gamma.r)].F(theta,phi), and we lost original E function, then imagine with a,b and gamma being r functions.
This is just my way to think. You may, of course, disagree. :)
...gamma is zero at r=0.85 because at r=0.85 the r-dependent part of Eθ is 1. An exponential raised to a zero value gives you 1. The constants defining Eθ (as well as the θ and phi dependent variables) are absorbed into "A":
This is great! I have a question though. How can gamma be 0 at r = .85? ..
...
Also, by assuming a standing wave solution, you are precluding there is any effect due to propagating waves. As @Ricvil said, the standing wave is the superposition of two propagating waves. The effect we are looking for pretty much requires that these two waves are not equal. So I don't think the assumption that beta=0 because they are standing waves is a good idea. It is like assuming the force we are looking for, doesn't exist.
I think it is required that beta =/= 0, or else the wave has no momentum to transfer to the frustum.
Thanks.
Todd
...Perhaps aero (or somebody else) will find a way to:
I also am very glad aero is here doing work that has effectively moved this group forward with answers garnered in meep that simply were not available to the group in any other fashion. And with your help we got some very good answers.
But a couple of questions arise in how we can accomplish this with the data being displayed as it currently is.
How can we even know that a TM mode can be excited when you declared that the displayed modes were of little value after the filtering of the data files to rid the display of the artifacts and flashing colors. The only way I can see is not to be dependent on the display of meep and post-process but use another program, Wolfram or something else?
I need to know how to forecast the future use of meep and post processing because this second build I'll be going after building a stable frustum with ceramic gold plated endplates and an active feedback system to assure mode and frequency lock. If I can't get the answers here than I'll need to take a longer path.
I was busy today tracking down and talking with old contacts that are going to try to get me the ceramics for the endplates. I'll need to tell them before too long what size I want them to be. The final shape of the ERD frustum will depend on how well meep and post processing can show what shape is optimal for it. For that we need as stable of an answer we can get. Simply for keeping a TE mode in a stabilized frustum, I think this is needed.
Shell
1) Plot all the electric fields with the same magnitude scale, and plot all the magnetic fields with the same magnitude scales
2) Plot the contour plots for the electromagnetic fields with an attached color bar showing the numerical magnitude of the contour colors.
I am not conversant with Meep but it seems to me that this need is something that many other users of Meep also have (to plot all the fields with the same magnitude and to be able to show the numerical value of the contours) and therefore may be an already existing command or something that somebody may have already documented how to do.
I know that other codes with which I am conversant (ANSYS, etc.) this is standard. Actually the ability to show the numerical value of the contours was available in ANSYS from its first versions back in the early 1980's.
steve@steve-p6720f:~$ h5topng -v -t 0 -z 214 ./Shell-2-d-dipole-loop-out/hx.h5
Using colormap "gray" in file "/usr/share/h5utils/colormaps/gray".
grayscale color map (white to black)
2 color entries read from colormap file.
Scaling opacity by 1
data rank = 4
------
reading from "./Shell-2-d-dipole-loop-out/hx.h5", slice at 214 in z dimension, slice at 0 in t dimension.
data ranges from -0.00012754 to 0.00012754.
writing "./Shell-2-d-dipole-loop-out/hx.png" from 196x196 input data.
all data range from -0.00012754 to 0.00012754.
EDIT: If I get a chance tonight I'll try to add Notsosureofit's formula to my spreadsheet and see what happens
ALL electric fields should be shown on the same scale and all magnetic fields should be shown to the same scale. Otherwise there is no comprehension.A common dB scale should be appropriate.
Why use a logarithm scale for showing the magnitude of the electromagnetic fields?ALL electric fields should be shown on the same scale and all magnetic fields should be shown to the same scale. Otherwise there is no comprehension.A common dB scale should be appropriate.
Why use a logarithm scale for showing the magnitude of the electromagnetic fields?ALL electric fields should be shown on the same scale and all magnetic fields should be shown to the same scale. Otherwise there is no comprehension.A common dB scale should be appropriate.
What advantage is there in using a logarithmic scale? I see disadvantages as a logarithmic scale would distort the fields and really distort the mode shapes which are usually displayed in texts with a linear scale and hence become difficult to recognize. We want to be able to identify the mode shapes so that we know whether TE or TM, etc.
(http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=36313.0;attach=632192;image)
Why use a logarithm scale for showing the magnitude of the electromagnetic fields?
What advantage is there in using a logarithmic scale? I see disadvantages as a logarithmic scale would distort the fields and really distort the mode shapes which are usually displayed in texts with a linear scale and hence become difficult to recognize. We want to be able to identify the mode shapes so that we know whether TE or TM, etc.
...
Also, by assuming a standing wave solution, you are precluding there is any effect due to propagating waves. As @Ricvil said, the standing wave is the superposition of two propagating waves. The effect we are looking for pretty much requires that these two waves are not equal. So I don't think the assumption that beta=0 because they are standing waves is a good idea. It is like assuming the force we are looking for, doesn't exist.
I think it is required that beta =/= 0, or else the wave has no momentum to transfer to the frustum.
Thanks.
Todd
Of course. But that is all that I solved. As I wrote in my post I only used the standing wave solution. Unequal travelling waves in opposite directions, interference, or other effects present with the RF feed on, or a force, are not going to be found here. I used only the standing wave solution, for which there is no force according to Maxwell's solution.
Before we go to Hankel functions we have to start from a known solution to see whether the method is sound and gives a correct solution to a known problem.
Particularly when Zeng and Fan have the incorrect solution and nobody from the peer reviewers caught it.
To consider a waveguide or an RF cavity transient solution I would have to use the same methodology using spherical Hankel functions instead of spherical Bessel functions, as I had posted previously :)
Piano piano si va sano e lontano
(http://caritas.diocesilucca.it/wp-content/uploads/dettagliopunto2010.gif)
For Shawyer to try and patent this before there was even a dream of a viable commercial product is ludicrous.
I vigorously disagree. Mr. Shawyer has, hypothetically, discovered something that we thought was impossible. As such, in addition to his Nobel prize, he is fully entitled to own that intellectual property for the full duration of the patent and take full financial advantage of it. His right to make a billion dollars on this is just as real as your right to make a billion dollars on any improvements you make to it.
A patent is a reward and incentive for the inventor's investment of effort, risk, failures, money, time, and life in creating a device or idea. If they choose to open source it or freely license it then that is their choice. They are under no ethical or moral obligation to do so.QuoteHe should have opened it up to research at the beginning.He did. He's been writing about it publicly for a decade to anyone who would listen. For his trouble he's been called a fraud and charlatan. He's been mocked and ridiculed. To imply that he's hoarded this to himself is a particularly bitter insult.QuoteBased on what I know, the current iteration is obviously not viable.Your knowledge is incorrect. He discovered the Shawyer effect and then spent years inventing, experimenting, and refining devices that generated thrust from RF energy. The device accomplished the "impossible". That certainly seems "viable" to me.QuoteIf members of the public are able to own a personal stake in something as evolutionary as this, some will gladly invest enormous amounts of effort, even with no guarantee of any financial reward or any success; like us.Mr. Shawyer built this technology "with no guarantee of any financial reward or any success." How is his contribution somehow inferior to what we would create?QuoteSo can it be done? Should it be done? If so, we need help...
We just have to make it roll. The rest is history.
Patent law is not simple at all. Even worse, it varies wildly by country and it changes over time. In the US, there is a tiny window for building a copy of a device to determine the accuracy of the specification, for the sole purpose of gratifying a philosophical taste, or curiosity, or for mere amusement. I currently work within those exceptions. Any use beyond that should be negotiated with Mr. Shawyer.
-eag
P.s. ... don't forget that Cannae has patents on this kit too. Even though their drive !did not work! they still own part of the IP.
Your knowledge is incorrect. He discovered the Shawyer effect and then spent years inventing, experimenting, and refining devices that generated thrust from RF energy. The device accomplished the "impossible". That certainly seems "viable" to me.
https://www.reddit.com/r/EmDrive/comments/3gkwcz/build_complete_initial_testing_done_emdrive_build/Dramatic in terms of the large measured thrust levels, but confusing too. Why does the measured thrust bang up and down like that under constant input power? Is this oscillation about the fulcrum? Is it a ballistic measuring device?
New EmDrive test results by PaulTheSwag posted few minutes ago on the reddit.
Dr Rodal, I think there is a problem again.
Standing waves.
In the cavity, at least, the fields are superpositions of two counter propagating waves, then one has (to simplify)
E=[a.exp(gamma.r)+b.exp(-gamma.r)].F(tetha,phi)
Repair, the expression above is just a aproximate model to fit the fields by exponential functions, where the correct is to use fractional spherical hankel functions (for spherical ends cavitys), where a,b and gamma will fataly be functions of r. At r>>1 the spherical hankel function decay with 1/r.
Then how to differentiate a destructive interference at node fields from a infinity attenuation?
Worse, even with a,b and gamma being constants, when one take the derivative of E above, because the two signals of gamma (outward/inward from/to apex cone) one has
dE/dr=gamma[a.exp(gamma.r) -b.exp(-gamma.r)].F(theta,phi), and we lost original E function, then imagine with a,b and gamma being r functions.
This is just my way to think. You may, of course, disagree. :)
There is NO approximation, and there is no fitting. There is NO exponential fit, because γ is not a constant here, γ is a function of r, defined to give the identical part of Eθ that is solely expressible in term of r . The meaning of γ is only as described by the mathematical expression, not more and not less.
γ is not a closed-form expression, it is not expressible by any known function known in any text. γ is given by Wolfram Mathematica as the solution of the differential equation, it is NOT a known classical function, it is NOT an exponential with a constant exponent multiplying r.
It is just a mapping of the original function into another function that gives exactly the same result.
It is exactly the same.
The solution Eθ in terms of γ exponential and A is identical to the one expressed in terms of Spherical Bessel functions and the Legendre Associated functions, it is just expressed in a different form.
Tomorrow I will post a comparison plot to show this identity. It is identical by construction
/////////////////////////////////////////////////////////////////
As to interference, separate waves and other issues present in the transient when the RF feed is ON, I have not dealt with those aspects. I have only dealt with the standing wave solution. To deal with the transient with the RF feed ON, yes I would have to use Hankel functions.
https://www.reddit.com/r/EmDrive/comments/3gkwcz/build_complete_initial_testing_done_emdrive_build/Dramatic in terms of the large measured thrust levels, but confusing too. Why does the measured thrust bang up and down like that under constant input power? Is this oscillation about the fulcrum? Is it a ballistic measuring device?
New EmDrive test results by PaulTheSwag posted few minutes ago on the reddit.
https://www.reddit.com/r/EmDrive/comments/3gkwcz/build_complete_initial_testing_done_emdrive_build/Dramatic in terms of the large measured thrust levels, but confusing too. Why does the measured thrust bang up and down like that under constant input power? Is this oscillation about the fulcrum? Is it a ballistic measuring device?
New EmDrive test results by PaulTheSwag posted few minutes ago on the reddit.
PS: I understand he says he used the NASA Eagleworks dimensions, if that is the case, the resonant frequency at near 2.45 GHz should be TM212 (transverse magnetic, same mode excited by Iulian Berca), instead of TE212 (transverse electric)
PS: I understand he says he used the NASA Eagleworks dimensions, if that is the case, the resonant frequency at near 2.45 GHz should be TM212 (transverse magnetic, same mode excited by Iulian Berca), instead of TE212 (transverse electric)
As calculated.
PS: I understand he says he used the NASA Eagleworks dimensions, if that is the case, the resonant frequency at near 2.45 GHz should be TM212 (transverse magnetic, same mode excited by Iulian Berca), instead of TE212 (transverse electric)
As calculated.
As calculated by NASA: 2.45 GHz TM212 (transverse MAGNETIC mode) (not TE212) for NASA's truncated cone dimensions (no dielectric insert)
My exact solution agrees with NASA
As calculated by NASA: 2.45 GHz TM212 (transverse MAGNETIC mode) (not TE212) for NASA's truncated cone dimensions (no dielectric insert)
My exact solution agrees with NASA
Full NASA report attached below
I'm still confused. Are we looking at a single impulsive event, or a steady-state force?The unraveling of the EM Drive "force measurement" this is what is great about replications.
The South African experiment does not show a constant steady-state force.
There is always some amount of damping in any set-up (if there would be no damping we would be able to have perpetual motion machines, which is impossible). But fair enough, since I have not had a chance to do detailed modeling of his set-up (I don't even know his dimensions) I withdraw my comments until I have the chance to model his set-up.I'm still confused. Are we looking at a single impulsive event, or a steady-state force?The unraveling of the EM Drive "force measurement" this is what is great about replications.
The South African experiment does not show a constant steady-state force.
His fulcrum is undamped and will oscillate for some time before settling at the final value. You know that so why the comment?
PS: I understand he says he used the NASA Eagleworks dimensions, if that is the case, the resonant frequency at near 2.45 GHz should be TM212 (transverse magnetic, same mode excited by Iulian Berca), instead of TE212 (transverse electric)
As calculated.
As calculated by NASA: 2.45 GHz TM212 (transverse MAGNETIC mode) (not TE212) for NASA's truncated cone dimensions (no dielectric insert)
My exact solution agrees with NASA
As calculated by NASA: 1.88 GHz TE212 (transverse ELECTRIC mode occurs at a much lower frequency than 2.45 GHz) for NASA's truncated cone dimensions (no dielectric insert)
My exact solution agrees with NASA
There is always some amount of damping in any set-up (if there would be no damping we would be able to have perpetual motion machines, which is impossible). But fair enough, since I have not had a chance to do detailed modeling of his set-up (I don't even know his dimensions) I withdraw my comments until I have the chance to model his set-up.
Can you provide a link to his cone dimensions, masses, displacement/force measuring device, etc., for me to model his experiment?
...
Proof of frustum resonance in any mode is measured Force generation. No Force generation, means the mode and resonance calc is not correct.
What NASA needs to show is the S11 return loss scans for those frequencies. When you see the return loss dB dips, then you know there is a resonant mode. Need a different antenna to properly excite TE and TM modes.
EW's internal frustum length only needs to be 3mm longer than SA Paul's frustum length for the 2.445GHz resonance to turn into a 2.422GHz resonance.
Thus I suggest the attached does show a TE212 resonance that EW found, Paul in SA found and my spreadsheet predicts.
Calculation of resonant frequencies in cavities is well-known and established. Has been replicated routinely in thousands of carefully designed experiments. Routinely done at CERN and other particle accelerators using Finite Element Analysis . The hundreds of thousands of readers of this thread can conduct their own calculations based on the NASA dimensions (see attached NASA report for dimensions frequencies and mode shape) and independently verify whether the mode shape at 2.45 GHz is TM212 or TE212
...
Proof of frustum resonance in any mode is measured Force generation. No Force generation, means the mode and resonance calc is not correct.
What NASA needs to show is the S11 return loss scans for those frequencies. When you see the return loss dB dips, then you know there is a resonant mode. Need a different antenna to properly excite TE and TM modes.
EW's internal frustum length only needs to be 3mm longer than SA Paul's frustum length for the 2.445GHz resonance to turn into a 2.422GHz resonance.
Thus I suggest the attached does show a TE212 resonance that EW found, Paul in SA found and my spreadsheet predicts.
Therefore according to you CERN, MIT, CalTech, Princeton, etc., and anybody that calculates frequencies and mode shapes of resonant cavities using Finite Element analysis and exact solutions are getting wrong results and they should immediately switch to using your Excel spreadsheet to calculate resonant frequencies and mode shapes?
I see the dimensions of the truncated cone there but I don't see enough details to do any modeling: no masses and most bothersome, no dimensions or description of the testing set-up except:There is always some amount of damping in any set-up (if there would be no damping we would be able to have perpetual motion machines, which is impossible). But fair enough, since I have not had a chance to do detailed modeling of his set-up (I don't even know his dimensions) I withdraw my comments until I have the chance to model his set-up.
Can you provide a link to his cone dimensions, masses, displacement/force measuring device, etc., for me to model his experiment?
https://www.reddit.com/r/EmDrive/comments/3gkwcz/build_complete_initial_testing_done_emdrive_build/
A knife-edge fulcrum is composed of a long balancing beam which rests on two razor edges. This allows for very sensitive measurement of minuscule forces such as those produced by an EMDrive.
One issue that could become a problem is air currents which could potentially give false positives. Once the frustum is set up on the fulcrum with a counterweight the fulcrum will be left for 10 minutes in the testing room. The setup will then be powered on for a burst of 10 seconds.
The frustum will be suspended in an upright position below the beam of the fulcrum. A laser will be attached to the other end of the beam which will project onto graph paper. This setup will detect any upwards or downwards forces on the frustum. A camera is positioned perpendicular to the graph paper to make measurements of the laser point.
My limited experience with the comsol EM module is it works fine!Calculation of resonant frequencies in cavities is well-known and established. Has been replicated routinely in thousands of carefully designed experiments. Routinely done at CERN and other particle accelerators using Finite Element Analysis . The hundreds of thousands of readers of this thread can conduct their own calculations based on the NASA dimensions (see attached NASA report for dimensions frequencies and mode shape) and independently verify whether the mode shape at 2.45 GHz is TM212 or TE212
As I said proof of the calc is seeing a S11 return loss dip at the calculated freq. Is easy to do. EW has the VNA to do the scan. So why no scans to back the calcs?
My limited experience with the comsol EM module is it works fine!
Without calculations it is difficult(not possible) to say a specific peak in the S-parameter plot is the target resonance.
I see the dimensions of the truncated cone there but I don't see enough details to do any modeling: no masses and most bothersome, no dimensions or description of the testing set-up except:
I see the dimensions of the truncated cone there but I don't see enough details to do any modeling: no masses and most bothersome, no dimensions or description of the testing set-up except:
This info is in his report. How is this not enough info to do an analysis?
Hypothesis Test 1 – NASA cavity size at 2450MHz
When microwaves are supplied into the cavity, a thrust will be produced by the frustum.
Hypothesis Test 2 – Frustum extended by 50 mm excited at 2450MHz
When microwaves are supplied into the cavity, a greater thrust will be produced by the increase in resonance.
The specifications of the frustum are as follows
Height (perpendicular): 228 mm (1) 278mm (2)
Big Diameter: 279.4mm
Small Diameter: 158.8mm
Material: Copper
Antenna location: 34.29 mm from Big Diameter
I see the dimensions of the truncated cone there but I don't see enough details to do any modeling: no masses and most bothersome, no dimensions or description of the testing set-up except
Do you understand how to model the dynamic oscillations in a testing set-up ?
Sigh. Hand over the discussion with TheTraveller of the South African experiment to you deltaMass and Frobnicat ;)Do you understand how to model the dynamic oscillations in a testing set-up ?
1st you need to confirm resonance. Last time that I remember you commented there was no resonance for the EW copper frustum at 2.45GHz. Might try that again and over the range +-30MHz.
there was no resonance for the EW copper frustum at 2.45GHzthat is a complete canard.
My limited experience with the comsol EM module is it works fine!
Without calculations it is difficult(not possible) to say a specific peak in the S-parameter plot is the target resonance.
Sure understand that. But if you do a scan on a cavity and the predicted resonance is not there, then what?
As far as I know, there were no scans to back up all the mode and freq calculations that EW did.
https://www.reddit.com/r/EmDrive/comments/3gkwcz/build_complete_initial_testing_done_emdrive_build/Interesting build, well documented. Would have liked to have seen some video. Seems like a similar setup to my fulcrum, which is all mechanical...eliminates sevaral digital variables. Nice use of solid copper. His extended fulcrum is similar to my nsf-1701. Feedpoint similat to spr and julians null point. Julian moved feedpoint halfway up frustum to get results. Congrats to his gold medal! That opens doors for further research for this young DIYer...bravo.
New EmDrive test results by PaulTheSwag posted few minutes ago on the reddit.
I have a simple VNA I plan to use to find resonance frequencies and it's simply a verification to the calculations. Over the years I know formulas are fine but deal in a virtual world and the calculated vs the real world seldom agree 100%. That's why the some of the waveguides are tuned with guys with tiny little hammers or with stub tuner screws.My limited experience with the comsol EM module is it works fine!
Without calculations it is difficult(not possible) to say a specific peak in the S-parameter plot is the target resonance.
Sure understand that. But if you do a scan on a cavity and the predicted resonance is not there, then what?
As far as I know, there were no scans to back up all the mode and freq calculations that EW did.
It becomes obvious that not every DIY builder has the same experience level of building experimental setups. By this I do not mean that there is a lack of experience on a technical skill-level, but on the data reporting...
Would it make sense to build some sort of checklist that would include all the needed required data, so that it can better assist those who work on a theoretical level?
Seeshell , fe, has many years of experience in building experimental devices, but not everybody is used to work in a scientific research environment and knows how to bring all their data.
Some guidelines for experimental reporting could help everybody, no?
That does my heart wonders to see a young man tackel this. Good for him!https://www.reddit.com/r/EmDrive/comments/3gkwcz/build_complete_initial_testing_done_emdrive_build/Interesting build, well documented. Would have liked to have seen some video. Seems like a similar setup to my fulcrum, which is all mechanical...eliminates sevaral digital variables. Nice use of solid copper. His extended fulcrum is similar to my nsf-1701. Feedpoint similat to spr and julians null point. Julian moved feedpoint halfway up frustum to get results. Congrats to his gold medal! That opens doors for further research for this young DIYer...bravo.
New EmDrive test results by PaulTheSwag posted few minutes ago on the reddit.
It becomes obvious that not every DIY builder has the same experience level of building experimental setups. By this I do not mean that there is a lack of experience on a technical skill-level, but on the data reporting...I agree. I had mentioned a while ago that it would be nice to create a NI labview standard for all drives to tested against. We should think about the methods and data logging. From that point, we test at a single test bed. I think shell is well on her way to creating a standardized test facility. With that will come the need to develop standardized test software, sensors., et al.
Would it make sense to build some sort of checklist that would include all the needed required data, so that it can better assist those who work on a theoretical level?
Seeshell , fe, has many years of experience in building experimental devices, but not everybody is used to work in a scientific research environment and knows how to bring all their data.
Some guidelines for experimental reporting could help everybody, no?
I might be up for it and I kind of like the idea. I cringe at the lack of safety used to get something to thrust and I see so many coming online right now. It's going to be desperately needed and standardized... but...It becomes obvious that not every DIY builder has the same experience level of building experimental setups. By this I do not mean that there is a lack of experience on a technical skill-level, but on the data reporting...I agree. I had mentioned a while ago that it would be nice to create a NI labview standard for all drives to tested against. We should think about the methods and data logging. From that point, we test at a single test bed. I think shell is well on her way to creating a standardized test facility. With that will come the need to develop standardized test software, sensors., et al.
Would it make sense to build some sort of checklist that would include all the needed required data, so that it can better assist those who work on a theoretical level?
Seeshell , fe, has many years of experience in building experimental devices, but not everybody is used to work in a scientific research environment and knows how to bring all their data.
Some guidelines for experimental reporting could help everybody, no?
Of course I have not asked shell if she's interested in becoming THE global test facility...;)
Unbelievable for TheTraveller to say such a canard. I even submitted to his attention (and SeeShell quoted in one of her messages) a complete table, for all NASA calculated frequencies from below 1GHz to 2.5GHz comparing my exact solution results to NASA results including TM212 at 2.45Ghz
Unbelievable for TheTraveller to say such a canard. I even submitted to his attention (and SeeShell quoted in one of her messages) a complete table, for all NASA calculated frequencies from below 1GHz to 2.5GHz comparing my exact solution results to NASA results including TM212 at 2.45Ghz
We were discussing the EW frustum and the lack of any 2.45GHz resonance in any mode, which we both agreed with. We both ending up suggested the EW copper frustum's length needed to be increased.
Remember or shall I dig it out? Trust me my memory is VERY good.
I had mentioned a while ago that it would be nice to create a NI labview standard for all drives to tested against.
Unbelievable for TheTraveller to say such a canard. I even submitted to his attention (and SeeShell quoted in one of her messages) a complete table, for all NASA calculated frequencies from below 1GHz to 2.5GHz comparing my exact solution results to NASA results including TM212 at 2.45Ghz
We were discussing the EW frustum and the lack of any 2.45GHz resonance in any mode, which we both agreed with. We both ending up suggested the EW copper frustum's length needed to be increased.
Remember or shall I dig it out? Trust me my memory is VERY good.
That is a canard. For you to insist on these false accusations without even bothering to verify whether your long-term memory is correct, after you just had to apologize for your short-term memory confusion (http://forum.nasaspaceflight.com/index.php?topic=38203.msg1415282#msg1415282) is just unfathomable.
It becomes obvious that not every DIY builder has the same experience level of building experimental setups. By this I do not mean that there is a lack of experience on a technical skill-level, but on the data reporting...I agree. I had mentioned a while ago that it would be nice to create a NI labview standard for all drives to tested against. We should think about the methods and data logging. From that point, we test at a single test bed. I think shell is well on her way to creating a standardized test facility. With that will come the need to develop standardized test software, sensors., et al.
Would it make sense to build some sort of checklist that would include all the needed required data, so that it can better assist those who work on a theoretical level?
Seeshell , fe, has many years of experience in building experimental devices, but not everybody is used to work in a scientific research environment and knows how to bring all their data.
Some guidelines for experimental reporting could help everybody, no?
Of course I have not asked shell if she's interested in becoming THE global test facility...;)
I had mentioned a while ago that it would be nice to create a NI labview standard for all drives to tested against.
Would it be possible to use:
http://www.myopenlab.de/startseite.html
Open source but simple, (too simple?)..
Unbelievable for TheTraveller to say such a canard. I even submitted to his attention (and SeeShell quoted in one of her messages) a complete table, for all NASA calculated frequencies from below 1GHz to 2.5GHz comparing my exact solution results to NASA results including TM212 at 2.45Ghz
We were discussing the EW frustum and the lack of any 2.45GHz resonance in any mode, which we both agreed with. We both ending up suggested the EW copper frustum's length needed to be increased.
Remember or shall I dig it out? Trust me my memory is VERY good.
That is a canard. For you to insist on these false accusations without even bothering to verify whether your long-term memory is correct, after you just had to apologize for your short-term memory confusion (http://forum.nasaspaceflight.com/index.php?topic=38203.msg1415282#msg1415282) is just unfathomable.
As for my long term memory it is correct:
http://forum.nasaspaceflight.com/index.php?topic=37642.msg1390632#msg1390632
What about yours?
As for the mode confusion, we all make mistakes, shall I point out a few of yours?
Sorry, I don't agree with the word "will not resonate" in absolute terms. You probably mean "will not resonate at the highest Q". There is always a spectral response of resonance, which will contains peaks with different amplitude at different frequencies.
That's the nicest thing someone has said in a long time. I'm flattered and thank you.It becomes obvious that not every DIY builder has the same experience level of building experimental setups. By this I do not mean that there is a lack of experience on a technical skill-level, but on the data reporting...I agree. I had mentioned a while ago that it would be nice to create a NI labview standard for all drives to tested against. We should think about the methods and data logging. From that point, we test at a single test bed. I think shell is well on her way to creating a standardized test facility. With that will come the need to develop standardized test software, sensors., et al.
Would it make sense to build some sort of checklist that would include all the needed required data, so that it can better assist those who work on a theoretical level?
Seeshell , fe, has many years of experience in building experimental devices, but not everybody is used to work in a scientific research environment and knows how to bring all their data.
Some guidelines for experimental reporting could help everybody, no?
Of course I have not asked shell if she's interested in becoming THE global test facility...;)
I regard your work & Shell's as being the high bar that other DIY builders should aspire too.
Unbelievable for TheTraveller to say such a canard. I even submitted to his attention (and SeeShell quoted in one of her messages) a complete table, for all NASA calculated frequencies from below 1GHz to 2.5GHz comparing my exact solution results to NASA results including TM212 at 2.45Ghz
We were discussing the EW frustum and the lack of any 2.45GHz resonance in any mode, which we both agreed with. We both ending up suggested the EW copper frustum's length needed to be increased.
Remember or shall I dig it out? Trust me my memory is VERY good.
That is a canard. For you to insist on these false accusations without even bothering to verify whether your long-term memory is correct, after you just had to apologize for your short-term memory confusion (http://forum.nasaspaceflight.com/index.php?topic=38203.msg1415282#msg1415282) is just unfathomable.
As for my long term memory it is correct:
http://forum.nasaspaceflight.com/index.php?topic=37642.msg1390632#msg1390632
What about yours?
As for the mode confusion, we all make mistakes, shall I point out a few of yours?
You are either very confused or there is something very wrong with you insisting with this canard:
1) The quotation you provide is NOT for the NASA dimensions it is for RFMwguy dimensions
2) In the quotation you provide I explicitly say that there is no such thing as "no resonance" because of mode participation at these frequencies, the complete opposite of what you claimQuote from: RodalSorry, I don't agree with the word "will not resonate" in absolute terms. You probably mean "will not resonate at the highest Q". There is always a spectral response of resonance, which will contains peaks with different amplitude at different frequencies.
3) I never stated "will not resonate". You are the one that stated that, and I explicitly answered that I did not agree with you.
At least Dr Rodal and I agree the standard EW frustum
Frustum big diameter m 0.2794000
Frustum small diameter m 0.1588000
Frustum centre length m 0.2286000
External Rf Hz 2,450,000,000
will not resonate at 2.45GHz.
...
Point is we both agreed the EW frustum length needed to be increased and following that advise RFMwguy increased his frustum length.
So please now show me any modes that resonant at 2.45GHz with the EW copper frustum. If you can't then thanks for the verification that we agree there are no resonant modes at 2.45GHz for the EW frustum.
Sorry, I don't agree with the word "will not resonate" in absolute terms. You probably mean "will not resonate at the highest Q". There is always a spectral response of resonance, which will contains peaks with different amplitude at different frequencies.
...
Point is we both agreed the EW frustum length needed to be increased and following that advise RFMwguy increased his frustum length.
So please now show me any modes that resonant at 2.45GHz with the EW copper frustum. If you can't then thanks for the verification that we agree there are no resonant modes at 2.45GHz for the EW frustum.
As I said before :Quote from: RodalSorry, I don't agree with the word "will not resonate" in absolute terms. You probably mean "will not resonate at the highest Q". There is always a spectral response of resonance, which will contains peaks with different amplitude at different frequencies.
I didn't agree with you then, and I don't agree with you now. Period.
As I said in a previous e-mail I don't plan to ever spend any time showing you anything.
The only mode shape that has ever been verified for an EM Drive has been TM212 for NASA with a dielectric that matched TM212 NASA prediction. NASA predicts TM212 at 2.45GHz with the NASA dimensions.
Here are the two png sets scaled to the maximum range of the E and H fields for the t=0 time slice. The ranges are from field components as follows:
# ez all data range from -0.000245405 to 0.000245405. E field big end
# hx all data range from -0.000538633 to 0.000538633. H field big end
# ez all data range from -4.04811e-05 to 4.04811e-05. E field small end
# hy all data range from -0.000287974 to 0.000287974. H field small end
Please look these png's over closely to be sure that this is what you want to see as it will be considerable effort to scale the png files in this way for the general case.
Or do you need to see the side views for this t = 0 case?
The numerical field intensity values may be available in some convenient way that I just don't know about, but I have looked. Other meepers looking would be very helpful.
They are available, just not convenienly, by using the "-verbose" switch on h5topng. Unfortunately, using that will require two separate runs, but I guess any method would require two separate runs at some level. Here is the verbose output from generating one png file.Quotesteve@steve-p6720f:~$ h5topng -v -t 0 -z 214 ./Shell-2-d-dipole-loop-out/hx.h5
Using colormap "gray" in file "/usr/share/h5utils/colormaps/gray".
grayscale color map (white to black)
2 color entries read from colormap file.
Scaling opacity by 1
data rank = 4
------
reading from "./Shell-2-d-dipole-loop-out/hx.h5", slice at 214 in z dimension, slice at 0 in t dimension.
data ranges from -0.00012754 to 0.00012754.
writing "./Shell-2-d-dipole-loop-out/hx.png" from 196x196 input data.
all data range from -0.00012754 to 0.00012754.
I manually made 12 runs of h5topng, and extracted the following data ranges.
Range of data values in Shell-2-d-dipole-loop64-out
slice t 00, z 15 Big end
ex all data range from -3.67269e-05 to 3.67269e-05.
ey all data range from -1.42517e-05 to 1.42517e-05.
ez all data range from -0.000245405 to 0.000245405.
hx all data range from -0.000538633 to 0.000538633.
hy all data range from -0.000356036 to 0.000356036.
hz all data range from -4.65749e-05 to 3.78542e-05.
slice t 00 z 214 Small end
ex all data range from -1.60461e-05 to 1.60461e-05.
ey all data range from -3.20985e-05 to 3.20985e-05.
ez all data range from -4.04811e-05 to 4.04811e-05.
hx all data range from -0.00012754 to 0.00012754.
hy all data range from -0.000287974 to 0.000287974.
hz all data range from -1.07156e-05 to 1.61666e-05.
As I understand you, what you need is to have three png files, ex, ey, ez scaled to the maximum range of the E components and three, hx hy, hz scaled to the maximum range for the H component - for each time slice and each of the 4 geometry slices per time slice. That would be the ez range and the hx range for the first case above, but note that max value and min value won't necessarily always be from the same component as the second hz range above indicates.
Scaling the range of values using this approach is quite unwieldy to do manually, as there are I believe 336 pngs for a standard data set as I have been using, but also, we might benefit by extending that data set to 2 full cycles, or even more.
Does anyone here want to volunteer to create a bash shell file that runs the data set in verbose mode capturing the terminal output in the log file, then scan that log file, extract the correct range of values and scale the h5topng max and min switches, then run the data set again for upload? Conceptually it should be straight forward but I only recognize bash in passing, are almost strangers. Of course one could use Octave or MatLab to read the log file and extract the pertinent data, or even write a purpose program that simply scans and extracts the data then writes a new shell file with as many h5topng command lines as needed. That might be safer and the 336 + command line shell file would be "throw away" so it wouldn't need to be "slick."
About PaulTheSwag's experiment:
1. What differentiates the thrust profile from one where only an initial impulse was produced?
2. What is a "double knife-edge fulcrum"? It makes no sense to me.
3. Do we know the power value?
OK. I now understand the double knife edge (actually triple).About PaulTheSwag's experiment:
1. What differentiates the thrust profile from one where only an initial impulse was produced?
2. What is a "double knife-edge fulcrum"? It makes no sense to me.
3. Do we know the power value?
2. Did you saw the pictures? http://imgur.com/a/iO7er
Ich denke es ist dieses Teil auf dem Foto ;)Nah - viel zu langsam.About PaulTheSwag's experiment:
1. What differentiates the thrust profile from one where only an initial impulse was produced?
2. What is a "double knife-edge fulcrum"? It makes no sense to me.
3. Do we know the power value?
2. Did you saw the pictures? http://imgur.com/a/iO7er
Do you have a helpful answer?
Dr Rodal, I think there is a problem again.
Standing waves.
In the cavity, at least, the fields are superpositions of two counter propagating waves, then one has (to simplify)
E=[a.exp(gamma.r)+b.exp(-gamma.r)].F(tetha,phi)
Repair, the expression above is just a aproximate model to fit the fields by exponential functions, where the correct is to use fractional spherical hankel functions (for spherical ends cavitys), where a,b and gamma will fataly be functions of r. At r>>1 the spherical hankel function decay with 1/r.
Then how to differentiate a destructive interference at node fields from a infinity attenuation?
Worse, even with a,b and gamma being constants, when one take the derivative of E above, because the two signals of gamma (outward/inward from/to apex cone) one has
dE/dr=gamma[a.exp(gamma.r) -b.exp(-gamma.r)].F(theta,phi), and we lost original E function, then imagine with a,b and gamma being r functions.
This is just my way to think. You may, of course, disagree. :)
There is NO approximation, and there is no fitting. There is NO exponential fit, because γ is not a constant here, γ is a function of r, defined to give the identical part of Eθ that is solely expressible in term of r . The meaning of γ is only as described by the mathematical expression, not more and not less.
γ is not a closed-form expression, it is not expressible by any known function known in any text. γ is given by Wolfram Mathematica as the solution of the differential equation, it is NOT a known classical function, it is NOT an exponential with a constant exponent multiplying r.
It is just a mapping of the original function into another function that gives exactly the same result.
It is exactly the same.
The solution Eθ in terms of γ exponential and A is identical to the one expressed in terms of Spherical Bessel functions and the Legendre Associated functions, it is just expressed in a different form.
Tomorrow I will post a comparison plot to show this identity. It is identical by construction
/////////////////////////////////////////////////////////////////
As to interference, separate waves and other issues present in the transient when the RF feed is ON, I have not dealt with those aspects. I have only dealt with the standing wave solution. To deal with the transient with the RF feed ON, yes I would have to use Hankel functions.
As promised, I attach a plot showing that the result of exponentiating the gamma function γ I derived (times -r)
Eθ = A e - γ r
results in exactly the same function as the exact electric field Eθ divided by A: Eθ /A. There is no approximation.
Again, this is by construction. The gamma function γ(r) cannot be expressed in terms of any known function appearing in any textbook, it has to be obtained as a numerical solution to the differential equation:
r dγ/dr + γ = - (1/Eθ)*dEθ/dr
By contrast, the γ function as defined by Zeng and Fan (who define it as γ = - (1/Eθ)*dEθ/dr )
does not result in Eθ / A = e - γ r as is easy to show. See the bottom attached image, showing divergence at small radius near the small base.
A plot of what proper definition of the gamma function γ(r) looks like is shown here:
http://forum.nasaspaceflight.com/index.php?topic=38203.msg1415088#msg1415088
ex all data range from -3.67269e-05 to 3.67269e-05.Here are the two png sets scaled to the maximum range of the E and H fields for the t=0 time slice. The ranges are from field components as follows:
# ez all data range from -0.000245405 to 0.000245405. E field big end
# hx all data range from -0.000538633 to 0.000538633. H field big end
# ez all data range from -4.04811e-05 to 4.04811e-05. E field small end
# hy all data range from -0.000287974 to 0.000287974. H field small end
Please look these png's over closely to be sure that this is what you want to see as it will be considerable effort to scale the png files in this way for the general case.
Or do you need to see the side views for this t = 0 case?
Thank you for going through the trouble to do this.
1) Assuming that the longitudinal axis is the z axis, this looks indeed like a TE mode (transverse electric) as the Hz mode (magnetic field in the longitudinal direction) is strong and the Ez (electric field in the longitudinal direction) is weak
however...
2) The blue areas in the fields: they look like the magnitude has been clipped.
(http://forum.nasaspaceflight.com/xindex.php,qaction=dlattach,3Btopic=38203.0,3Battach=1055383,3Bimage.pagespeed.ic.hjMMacoPKv.webp)
They look like ContourPlots in Mathematica when I use PlotRange with a range smaller than the full magnitude, so the contours get cliped. I would double check whether magnitudes have not been clipped.
3) Is there some means to control the number of contour values in the contour plots? It looks to me like there are more contour levels than the number of colors available, as a result colors keep repeating themselves. What one wants is to have blue represent the lowest magnitude and red the highest magnitude, instead of red/green/blue/yellow patterns being repeated cyclically.
(http://forum.nasaspaceflight.com/xindex.php,qaction=dlattach,3Btopic=38203.0,3Battach=1055381,3Bimage.pagespeed.ic.p_0CAdsbWT.webp)
...Yes, it would be better to have everything under
ex all data range from -3.67269e-05 to 3.67269e-05.
ey all data range from -1.42517e-05 to 1.42517e-05.
ez all data range from -0.000245405 to 0.000245405.
Of course they have been clipped. Look at the data ranges for the three E field components. Anything below the data range (or above, but that won't happen) are well ....from the manual: "Data values below or above this range will be treated as if they were min or max respectively." I suppose I could use the range from the minimum of the field to the maximum. Not minimum/ maximum of the most energetic component. To do so would be only a little more difficult, but would that be better? I can't guess without looking.
Ich denke es ist dieses Teil auf dem Foto ;)Nah - viel zu langsam.About PaulTheSwag's experiment:
1. What differentiates the thrust profile from one where only an initial impulse was produced?
2. What is a "double knife-edge fulcrum"? It makes no sense to me.
3. Do we know the power value?
2. Did you saw the pictures? http://imgur.com/a/iO7er
Do you have a helpful answer?
How about my other two questions - the power? and why not just an impulse?I can't give you a answer, but ask him self :)
About PaulTheSwag's experiment:
1. What differentiates the thrust profile from one where only an initial impulse was produced?
2. What is a "double knife-edge fulcrum"? It makes no sense to me.
3. Do we know the power value?Quotehttp://i.imgur.com/57n4rP7.jpg
double edge knife
And here is his report
https://docs.google.com/document/d/10uC31t-fb6sGAouICB1x7wF3F17qcBO5oie5_07Ethk/edit?pli=1
Links to it all.
https://www.reddit.com/r/EmDrive/comments/3gkwcz/build_complete_initial_testing_done_emdrive_build/
ex all data range from -3.67269e-05 to 3.67269e-05.Here are the two png sets scaled to the maximum range of the E and H fields for the t=0 time slice. The ranges are from field components as follows:
# ez all data range from -0.000245405 to 0.000245405. E field big end
# hx all data range from -0.000538633 to 0.000538633. H field big end
# ez all data range from -4.04811e-05 to 4.04811e-05. E field small end
# hy all data range from -0.000287974 to 0.000287974. H field small end
Please look these png's over closely to be sure that this is what you want to see as it will be considerable effort to scale the png files in this way for the general case.
Or do you need to see the side views for this t = 0 case?
Thank you for going through the trouble to do this.
1) Assuming that the longitudinal axis is the z axis, this looks indeed like a TE mode (transverse electric) as the Hz mode (magnetic field in the longitudinal direction) is strong and the Ez (electric field in the longitudinal direction) is weak
however...
2) The blue areas in the fields: they look like the magnitude has been clipped.
(http://forum.nasaspaceflight.com/xindex.php,qaction=dlattach,3Btopic=38203.0,3Battach=1055383,3Bimage.pagespeed.ic.hjMMacoPKv.webp)
They look like ContourPlots in Mathematica when I use PlotRange with a range smaller than the full magnitude, so the contours get cliped. I would double check whether magnitudes have not been clipped.
3) Is there some means to control the number of contour values in the contour plots? It looks to me like there are more contour levels than the number of colors available, as a result colors keep repeating themselves. What one wants is to have blue represent the lowest magnitude and red the highest magnitude, instead of red/green/blue/yellow patterns being repeated cyclically.
(http://forum.nasaspaceflight.com/xindex.php,qaction=dlattach,3Btopic=38203.0,3Battach=1055381,3Bimage.pagespeed.ic.p_0CAdsbWT.webp)
ey all data range from -1.42517e-05 to 1.42517e-05.
ez all data range from -0.000245405 to 0.000245405.
Of course they have been clipped. Look at the data ranges for the three E field components. Anything below the data range (or above, but that won't happen) are well ....from the manual: "Data values below or above this range will be treated as if they were min or max respectively." I suppose I could use the range from the minimum of the field to the maximum. Not minimum/ maximum of the most energetic component. To do so would be only a little more difficult, but would that be better? I can't guess without looking.
The numerical field intensity values may be available in some convenient way that I just don't know about, but I have looked. Other meepers looking would be very helpful.
They are available, just not convenienly, by using the "-verbose" switch on h5topng. Unfortunately, using that will require two separate runs, but I guess any method would require two separate runs at some level. Here is the verbose output from generating one png file.Quotesteve@steve-p6720f:~$ h5topng -v -t 0 -z 214 ./Shell-2-d-dipole-loop-out/hx.h5
Using colormap "gray" in file "/usr/share/h5utils/colormaps/gray".
grayscale color map (white to black)
2 color entries read from colormap file.
Scaling opacity by 1
data rank = 4
------
reading from "./Shell-2-d-dipole-loop-out/hx.h5", slice at 214 in z dimension, slice at 0 in t dimension.
data ranges from -0.00012754 to 0.00012754.
writing "./Shell-2-d-dipole-loop-out/hx.png" from 196x196 input data.
all data range from -0.00012754 to 0.00012754.
I manually made 12 runs of h5topng, and extracted the following data ranges.
Range of data values in Shell-2-d-dipole-loop64-out
slice t 00, z 15 Big end
ex all data range from -3.67269e-05 to 3.67269e-05.
ey all data range from -1.42517e-05 to 1.42517e-05.
ez all data range from -0.000245405 to 0.000245405.
hx all data range from -0.000538633 to 0.000538633.
hy all data range from -0.000356036 to 0.000356036.
hz all data range from -4.65749e-05 to 3.78542e-05.
slice t 00 z 214 Small end
ex all data range from -1.60461e-05 to 1.60461e-05.
ey all data range from -3.20985e-05 to 3.20985e-05.
ez all data range from -4.04811e-05 to 4.04811e-05.
hx all data range from -0.00012754 to 0.00012754.
hy all data range from -0.000287974 to 0.000287974.
hz all data range from -1.07156e-05 to 1.61666e-05.
As I understand you, what you need is to have three png files, ex, ey, ez scaled to the maximum range of the E components and three, hx hy, hz scaled to the maximum range for the H component - for each time slice and each of the 4 geometry slices per time slice. That would be the ez range and the hx range for the first case above, but note that max value and min value won't necessarily always be from the same component as the second hz range above indicates.
Scaling the range of values using this approach is quite unwieldy to do manually, as there are I believe 336 pngs for a standard data set as I have been using, but also, we might benefit by extending that data set to 2 full cycles, or even more.
Does anyone here want to volunteer to create a bash shell file that runs the data set in verbose mode capturing the terminal output in the log file, then scan that log file, extract the correct range of values and scale the h5topng max and min switches, then run the data set again for upload? Conceptually it should be straight forward but I only recognize bash in passing, are almost strangers. Of course one could use Octave or MatLab to read the log file and extract the pertinent data, or even write a purpose program that simply scans and extracts the data then writes a new shell file with as many h5topng command lines as needed. That might be safer and the 336 + command line shell file would be "throw away" so it wouldn't need to be "slick."
Please find attached a simple python program. Rename to h5topng_range.py. Usage:
python h5topng_range.py --logfile filename.txt
Output is to stdout, so some post processing will be necessary to get this to run in bash (I'm on windows, no access to bash until tonight). Tested with version 3.x should work with 2.5+ but I haven't tested. Uses the argparse library which is standard in version 3.x.
For the sample h5topng output quoted above, contained in "filename.txt", this produces the output:
h5topng -t 0 -z 214 -m -0.00012754 -M 0.00012754 ./Shell-2-d-dipole-loop-out/hx.h5
The numbers are pulled from the "all range data from" line and not the "data ranges from" line. The "-z" switch is parametric based on the "reading from" line. The "-t" is hardcoded, but can be made parametric if necessary, the value after "-t" is, of course, parametric.
Maybe artefacts from the grid but there are strong currents in the wall and corresponding fields...ex all data range from -3.67269e-05 to 3.67269e-05.Here are the two png sets scaled to the maximum range of the E and H fields for the t=0 time slice. The ranges are from field components as follows:
# ez all data range from -0.000245405 to 0.000245405. E field big end
# hx all data range from -0.000538633 to 0.000538633. H field big end
# ez all data range from -4.04811e-05 to 4.04811e-05. E field small end
# hy all data range from -0.000287974 to 0.000287974. H field small end
Please look these png's over closely to be sure that this is what you want to see as it will be considerable effort to scale the png files in this way for the general case.
Or do you need to see the side views for this t = 0 case?
Thank you for going through the trouble to do this.
1) Assuming that the longitudinal axis is the z axis, this looks indeed like a TE mode (transverse electric) as the Hz mode (magnetic field in the longitudinal direction) is strong and the Ez (electric field in the longitudinal direction) is weak
however...
2) The blue areas in the fields: they look like the magnitude has been clipped.
(http://forum.nasaspaceflight.com/xindex.php,qaction=dlattach,3Btopic=38203.0,3Battach=1055383,3Bimage.pagespeed.ic.hjMMacoPKv.webp)
They look like ContourPlots in Mathematica when I use PlotRange with a range smaller than the full magnitude, so the contours get cliped. I would double check whether magnitudes have not been clipped.
3) Is there some means to control the number of contour values in the contour plots? It looks to me like there are more contour levels than the number of colors available, as a result colors keep repeating themselves. What one wants is to have blue represent the lowest magnitude and red the highest magnitude, instead of red/green/blue/yellow patterns being repeated cyclically.
(http://forum.nasaspaceflight.com/xindex.php,qaction=dlattach,3Btopic=38203.0,3Battach=1055381,3Bimage.pagespeed.ic.p_0CAdsbWT.webp)
ey all data range from -1.42517e-05 to 1.42517e-05.
ez all data range from -0.000245405 to 0.000245405.
Of course they have been clipped. Look at the data ranges for the three E field components. Anything below the data range (or above, but that won't happen) are well ....from the manual: "Data values below or above this range will be treated as if they were min or max respectively." I suppose I could use the range from the minimum of the field to the maximum. Not minimum/ maximum of the most energetic component. To do so would be only a little more difficult, but would that be better? I can't guess without looking.
I have a silly question. If the data values are clipped why am I still seeing artifacts on the side walls?
shell
Dr. Rodal,Today (morning) someone pointed out that it may be helpful to use a logarithmic scale, did you try that in the actual case? (one try to compare with the mag. scale?)
I was trying to figure out a way to communicate what I thought was going on, but I think I was wrong. It's simple -
Draw 3 sine waves on a sheet of paper, x-y axis, each symmetric about the x axis, but with different amplitudes. Then draw horizontal lines tangent to the extreme positive and negative values of each sine wave. I used the y value of the top and bottom horizontal line.
So the weaker sign waves are not clipped, they just don't have enough power to show up on the scale of the strongest.
I'll see about using a different color map.
Dr. Rodal,
I was trying to figure out a way to communicate what I thought was going on, but I think I was wrong. It's simple -
Draw 3 sine waves on a sheet of paper, x-y axis, each symmetric about the x axis, but with different amplitudes. Then draw horizontal lines tangent to the extreme positive and negative values of each sine wave. I used the y value of the top and bottom horizontal line.
So the weaker sign waves are not clipped, they just don't have enough power to show up on the scale of the strongest.
I'll see about using a different color map.
I saw that and frankly it gave me a nice chuckle. Two points on a log scale?Dr. Rodal,Today (morning) someone pointed out that it may be helpful to use a logarithmic scale, did you try that in the actual case? (one try to compare with the mag. scale?)
I was trying to figure out a way to communicate what I thought was going on, but I think I was wrong. It's simple -
Draw 3 sine waves on a sheet of paper, x-y axis, each symmetric about the x axis, but with different amplitudes. Then draw horizontal lines tangent to the extreme positive and negative values of each sine wave. I used the y value of the top and bottom horizontal line.
So the weaker sign waves are not clipped, they just don't have enough power to show up on the scale of the strongest.
I'll see about using a different color map.
Other color map for the mag. scale like you sad could be also helpful i think.
BTW: great work, thanks for spend your time!
....
bluered (opaque blue to transparent white to opaque red). I have several color maps available, this is just the first try. I personally don't like it very much.
For very good reasons: IMHO a logarithmic scale is the complete opposite of what one wants to do to display mode shapes for these purposes: it will increase the number of contours in the low range and it will decrease them in the high range.I saw that and frankly it gave me a nice chuckle. Two points on a log scale?Dr. Rodal,Today (morning) someone pointed out that it may be helpful to use a logarithmic scale, did you try that in the actual case? (one try to compare with the mag. scale?)
I was trying to figure out a way to communicate what I thought was going on, but I think I was wrong. It's simple -
Draw 3 sine waves on a sheet of paper, x-y axis, each symmetric about the x axis, but with different amplitudes. Then draw horizontal lines tangent to the extreme positive and negative values of each sine wave. I used the y value of the top and bottom horizontal line.
So the weaker sign waves are not clipped, they just don't have enough power to show up on the scale of the strongest.
I'll see about using a different color map.
Other color map for the mag. scale like you sad could be also helpful i think.
BTW: great work, thanks for spend your time!
See: http://ab-initio.mit.edu/h5utils/h5topng-man.html (http://ab-initio.mit.edu/h5utils/h5topng-man.html) Look really, really closely for the log scale output, then tell me what you find.
Or maybe it would be more fruitful to look here: http://www.hdfgroup.org/products/java/hdfview/UsersGuide/ug05spreadsheet.html#ug05subset_transpose (http://www.hdfgroup.org/products/java/hdfview/UsersGuide/ug05spreadsheet.html#ug05subset_transpose)
My point is that logarithmic seems to be an alien concept to meep and it's support software.
A logarithmic scale is a nonlinear scale used when there is a large range of quantities. Common uses include the earthquake strength, sound loudness, light intensity, and pH of solutions.
It is based on orders of magnitude, rather than a standard linear scale, so each mark on the scale is the previous mark multiplied by a value.
OK i can follow your explanation (high vs. low field strength), but i am not sure in view of the resulting pictures. It would be soften the edges we look since the rescaling.For very good reasons: a logarithmic scale is the opposite of what one wants to do to display mode shapes for these purposes: it will increase the number of contours in the low range and it will decreased them in the high range.I saw that and frankly it gave me a nice chuckle. Two points on a log scale?Dr. Rodal,Today (morning) someone pointed out that it may be helpful to use a logarithmic scale, did you try that in the actual case? (one try to compare with the mag. scale?)
I was trying to figure out a way to communicate what I thought was going on, but I think I was wrong. It's simple -
Draw 3 sine waves on a sheet of paper, x-y axis, each symmetric about the x axis, but with different amplitudes. Then draw horizontal lines tangent to the extreme positive and negative values of each sine wave. I used the y value of the top and bottom horizontal line.
So the weaker sign waves are not clipped, they just don't have enough power to show up on the scale of the strongest.
I'll see about using a different color map.
Other color map for the mag. scale like you sad could be also helpful i think.
BTW: great work, thanks for spend your time!
See: http://ab-initio.mit.edu/h5utils/h5topng-man.html (http://ab-initio.mit.edu/h5utils/h5topng-man.html) Look really, really closely for the log scale output, then tell me what you find.
Or maybe it would be more fruitful to look here: http://www.hdfgroup.org/products/java/hdfview/UsersGuide/ug05spreadsheet.html#ug05subset_transpose (http://www.hdfgroup.org/products/java/hdfview/UsersGuide/ug05spreadsheet.html#ug05subset_transpose)
My point is that logarithmic seems to be an alien concept to meep and it's support software.QuoteA logarithmic scale is a nonlinear scale used when there is a large range of quantities. Common uses include the earthquake strength, sound loudness, light intensity, and pH of solutions.
It is based on orders of magnitude, rather than a standard linear scale, so each mark on the scale is the previous mark multiplied by a value.
It will distort all the shapes. Logarithmic scales are suitable when you have an exponential increasing behavior. Not suitable for the fields.
May be suitable to plot attenuation, not for the fields
...Well it is just my opinion of course.
OK i can follow your explanation (high vs. low field strength), but i am not sure in view of the resulting pictures. It would be soften the edges we look since the rescaling.
You are the expert here, if you think i isn't helpful then forget it, no problem with that.
And yes it's much better with the new color map!!
Yes you should be right, its a little bi t late and i am tired today....Well it is just my opinion of course.
OK i can follow your explanation (high vs. low field strength), but i am not sure in view of the resulting pictures. It would be soften the edges we look since the rescaling.
You are the expert here, if you think i isn't helpful then forget it, no problem with that.
And yes it's much better with the new color map!!
Let's clarify it with an example: a logarithmic scale is eminently suited to rank earthquakes because each level changes by an order of magnitude. The difference between an earthquake with a level of 9 from a level of 8 is much greater than the difference between an earthquake between a level of 5 and a level of 4.
Ditto for sound.
Both for sound and earthquakes it makes sense to have a scale that has more levels at low magnitude and less levels at high magnitude.
Now, for the electromagnetic fields, we do not have a scale of electromagnetism where we want to minimize the number of levels at high magnitude and maximize the number of levels at low magnitude.
A linear scale for the mode shapes in EM Drive cavities is fine because we don't have singularities.
A logarithmic scale would make sense for this kind of shape: see the attachment for attenuation where the attenuation goes to Infinity at each end, the plot is clipped at the ends because a linear scale cannot show the singularities at each end.
Ok since the photons inside the cavity are traveling in a medium at a group velocity <c, we can technically define a frame where the photon is at rest relative to the cavity walls. I can't justify a reason to not treat them as massive particles in calculations.
This is a special case since we're not dealing with photons in vacuum. Does this sound controversial to anyone? That means switching to relativistic momentum.
http://hyperphysics.phy-astr.gsu.edu/hbase/relativ/relmom.html
This ref was shared by someone else recently and I think it is significant.
http://arxiv.org/abs/0708.3519
I have a simple VNA I plan to use to find resonance frequencies and it's simply a verification to the calculations.My limited experience with the comsol EM module is it works fine!
Without calculations it is difficult(not possible) to say a specific peak in the S-parameter plot is the target resonance.
Sure understand that. But if you do a scan on a cavity and the predicted resonance is not there, then what?
As far as I know, there were no scans to back up all the mode and freq calculations that EW did.
...
Even NASA should have used VNAs in air and vacuum just to check and I'm not sure they did.
...
Your Quote link to Rodal's comment (about "unraveling") does not work. Can you please provide a working link?I'm still confused. Are we looking at a single impulsive event, or a steady-state force?The unraveling of the EM Drive "force measurement" this is what is great about replications.
The South African experiment does not show a constant steady-state force.
His fulcrum is undamped and will oscillate for some time before settling at the final value. You know that so why the comment?
Same as mine, 3 blades, 2 balance points.OK. I now understand the double knife edge (actually triple).About PaulTheSwag's experiment:
1. What differentiates the thrust profile from one where only an initial impulse was produced?
2. What is a "double knife-edge fulcrum"? It makes no sense to me.
3. Do we know the power value?
2. Did you saw the pictures? http://imgur.com/a/iO7er
(http://www.brainyquote.com/photos/c/charlescalebcolton203963.jpg)Same as mine, 3 blades, 2 balance points.OK. I now understand the double knife edge (actually triple).About PaulTheSwag's experiment:
1. What differentiates the thrust profile from one where only an initial impulse was produced?
2. What is a "double knife-edge fulcrum"? It makes no sense to me.
3. Do we know the power value?
2. Did you saw the pictures? http://imgur.com/a/iO7er
How about my other two questions - the power? and why not just an impulse?
Ok since the photons inside the cavity are traveling in a medium at a group velocity <c, we can technically define a frame where the photon is at rest relative to the cavity walls. I can't justify a reason to not treat them as massive particles in calculations.
This is a special case since we're not dealing with photons in vacuum. Does this sound controversial to anyone? That means switching to relativistic momentum.
http://hyperphysics.phy-astr.gsu.edu/hbase/relativ/relmom.html
This ref was shared by someone else recently and I think it is significant.
http://arxiv.org/abs/0708.3519
Two balance points for me.(http://www.brainyquote.com/photos/c/charlescalebcolton203963.jpg)Same as mine, 3 blades, 2 balance points.OK. I now understand the double knife edge (actually triple).About PaulTheSwag's experiment:
1. What differentiates the thrust profile from one where only an initial impulse was produced?
2. What is a "double knife-edge fulcrum"? It makes no sense to me.
3. Do we know the power value?
2. Did you saw the pictures? http://imgur.com/a/iO7er
That looks very promising.
No, the -t is what it is, the -x -y and -z are parameters, (one set per png file). But it looks like the shell file will need to undergo major changes. I've attached my shell file (change the extension to .sh). It works for what I have been doing but I am forced by h5topng to copy the .png files into the sub-folders from the -out folder. The new desire to set min/max for each value of t, x, y, z will force us to discard this approach and adopt a naming convention something like I use for the csv files. That shell file is also attached (changed extension) but h5totxt handles the sub-directory correctly so no file moving is needed.
As for running it in bash? Not necessary until the h5topng commands are fully formulated and written to a shell file. You can do all of that in Python if that is your language of choice. Then run that shell file in bash.
You will likely need to create a set of h5 files to run your tests against. Don't go to to much work until you do that because I'm not sure that the single case of data that I generated and posted is representative of what h5topng outputs when multiple files are generated. It's sure not what the attached shell file logs, but then, the attached is probably not representative of the ultimate design, either.
and see the manual, it's short:
http://ab-initio.mit.edu/h5utils/h5topng-man.html (http://ab-initio.mit.edu/h5utils/h5topng-man.html)
NSF-1701 Update 8/11/15. Assembly of frustum complete. Final weigh-in 2.383 kg. (grill) Thermometer installed, thanks to an idea from a pal here on NSF. Electrodes (solid copper wire) and terminal strip attached. Frustum is pictured upside down, as test will have small end closest to floor.That is simply beautiful. Nice looking build!
Final assembly on microwave (oven) controller just about done. Terminal strip on back and all wired up. Outside case reinstalled, fan and turntable motor disabled. All that's left is to attach copper wire and galinstan copper cups.
Just about at the end of the build phase!!!!!!!!!!!
Thanks shell. Get that roof fixed, we can't have leaks at our global test facility ;)NSF-1701 Update 8/11/15. Assembly of frustum complete. Final weigh-in 2.383 kg. (grill) Thermometer installed, thanks to an idea from a pal here on NSF. Electrodes (solid copper wire) and terminal strip attached. Frustum is pictured upside down, as test will have small end closest to floor.That is simply beautiful. Nice looking build!
Final assembly on microwave (oven) controller just about done. Terminal strip on back and all wired up. Outside case reinstalled, fan and turntable motor disabled. All that's left is to attach copper wire and galinstan copper cups.
Just about at the end of the build phase!!!!!!!!!!!
So you got to work on your build I got to smear some tar a roof that was leaking. Something isn't right here.... hmmmm
Very nice.
Shell
@Imbfan-
Making good progress. One simple thing
Direction('-0x0', 'x', .456, .567),
Direction('-0y0', 'y', .678, .789),
should be
Direction('-0 -x 0', 'x', .456, .567),
Direction('-0 -y 0', 'y', .678, .789),
The -0 is a switch telling h5totxt to use the center of the lattice as the origin, the -x is a switch telling to cut the x axis, that is, look at the y,z plane, and of course the 0 says cut along the x=0 value. Similar for y. And h5totxt and h5topng requires a space to separate switches/values.
I'll look in more detail soon but that was all I saw on first read.
aero
-0
Shift the origin of the x/y/z slice coordinates to the dataset center, so that e.g. -0 -x 0 (or more compactly -0x0) returns the central x plane of the dataset instead of the edge x plane. (-t coordinates are not affected.)
I have a simple VNA I plan to use to find resonance frequencies and it's simply a verification to the calculations.My limited experience with the comsol EM module is it works fine!
Without calculations it is difficult(not possible) to say a specific peak in the S-parameter plot is the target resonance.
Sure understand that. But if you do a scan on a cavity and the predicted resonance is not there, then what?
As far as I know, there were no scans to back up all the mode and freq calculations that EW did.
...
Even NASA should have used VNAs in air and vacuum just to check and I'm not sure they did.
...
I'd like to propose a logical progression to the VNA analysis: characterize each experimental frustum at multiple temperatures
@deltaMass recently proposed that thermal data could be used as an approximation to how well tuned the frustum was to the source RF feed. To continue the line of thought, if one could characterize a frustum at discrete temperatures using a VNA , then one could theoretically build a control loop using frustum temperature that varied frequency and/or impedance controls without having to perform real-time VSWR or sample port analysis.
Effectively I'm proposing that a lookup table could be constructed that indicates the optimal experimental control settings for each temperature point. As the frustum heats up, the optimal experimental control settings can be obtained from the table. As an implementation detail, one could use curve-fitting to build an equation or use simplistic "if-then-else" to drive the control loop outputs.
While the temperature is likely to be the dominant frustum parameter than impact bandpass characteristics and impedance, other parameters may also be important to in order to implement a control loop that yields repeatable results (i.e. frustum orientation, humidity, etc).
EDIT: On further thought, one might need multiple temperature inputs from different areas on the frustum geometry. The back-of-napkin reasoning being that temperature differences at certain key locations may have a more pronounced effect on bandpass characteristics and impedance than a single "average" frustum temperature. I'd guess that the temperature of the "big end" and "small end" are the two dominant parameters.
I remember that now that you mention it. So it likely works as you have it.@Imbfan-
Making good progress. One simple thing
Direction('-0x0', 'x', .456, .567),
Direction('-0y0', 'y', .678, .789),
should be
Direction('-0 -x 0', 'x', .456, .567),
Direction('-0 -y 0', 'y', .678, .789),
The -0 is a switch telling h5totxt to use the center of the lattice as the origin, the -x is a switch telling to cut the x axis, that is, look at the y,z plane, and of course the 0 says cut along the x=0 value. Similar for y. And h5totxt and h5topng requires a space to separate switches/values.
I'll look in more detail soon but that was all I saw on first read.
aero
From the manual you linked earlier:Quote-0
Shift the origin of the x/y/z slice coordinates to the dataset center, so that e.g. -0 -x 0 (or more compactly -0x0) returns the central x plane of the dataset instead of the edge x plane. (-t coordinates are not affected.)
I could not test, but it's no problem to switch it if it doesn't work.
Height without the cylindrical endpart: 21.87mm
Height of cylindrical endpart: 5mm
Diameter small end: 16.12mm
Diameter big end: 29.64mm
Frequency is tuneable within 23 to 25 GHz (maybe more, but then the generator works out of spec)
The small end wall will be movable within the cylindrical endpart by a servo for automatic testing.
The endplates are flat - but a sphrical mod is also possible, because the cavity ends are open so we can flange different endplates to it.
Many thanx for your analysis, it´s really amazing that you´re doing that for us.
Do you also need the antenna position/antenna length, or does it not matter?
The current board uses a 3/4 lambda of 24.125GHz
The antenna hole is 5.55mm below the cylindrical endpart.
If this is wrong, we can make another drill. Unfortunately I could not find much information about the antenna position in EMdrives, just the standard 1/4lambda distance from the wall for usual waveguides.
...May I suggest somebody add this info to the wiki very shortly?...
NSF-1701 Update 8/11/15. Assembly of frustum complete. Final weigh-in 2.383 kg. (grill) Thermometer installed, thanks to an idea from a pal here on NSF. Electrodes (solid copper wire) and terminal strip attached. Frustum is pictured upside down, as test will have small end closest to floor.
Final assembly on microwave (oven) controller just about done. Terminal strip on back and all wired up. Outside case reinstalled, fan and turntable motor disabled. All that's left is to attach copper wire and galinstan copper cups.
Just about at the end of the build phase!!!!!!!!!!!
We continue by showing γ for the Yang cavity at 15 ° to the previously calculated for 6 ° side by side.
1) The 6 ° Yang/Shell geometry:
bigDiameter = 0.201(*meter*);
smallDiameter = 0.1492(*meter*);
axialLength = 0.24(*meter*);
r1 = 0.693281 (*meter*); (*spherical small radius *)
r2 = 0.933978 (*meter*); (*spherical large radius *)
θw = 6.15933 ° (*degrees*); (*half-cone angle*)
2) The 15 ° Yang EM Drive geometry:
bigDiameter = 0.247 (*meter*);
smallDiameter = 0.1144253 (*meter*);
axialLength = 0.24 (*meter*);
r1 = 0.211022 (*meter*);
r2 = 0.455515 (*meter*);
θw = 15.44 ° (*degrees*); (*half-cone angle*)
the geometry we consider is as shown in this image:
(http://gregegan.customer.netspace.net.au/SCIENCE/Cavity/CavityShape.gif)
We show below:
1) γ(r) vs. r for TE011 15 ° geometry
2) γ(r) vs. r for TE011 6 ° geometry
Clearly, the geometrical attenuation γ(r) is much greater for the Yang cavity at 15 ° and closer to the vertex than the previously calculated for 6 ° and farther from the vertex . When the attenuation gradient is correctly calculated, the attenuation is clearly greater for higher angles and closer to the vertex.
__________________________
These are calculations of the gamma function γ as a measure of exponential geometrical attenuation:
Eθ = A e - γ r
where the gamma function γ(r) (which cannot be expressed in terms of any known function appearing in any textbook), has to be obtained as a numerical solution to the differential equation
r dγ/dr + γ = - (1/Eθ)*dEθ/dr
More generally, experiments to validate or disconfirm, in suitable geometries, the various terms of our proposed generalized equation of motion (7) would evidently be desirable. The Lorentz force is the only one of those terms currently known beyond doubt to be physically valid. For a century too much has been left to accepted electromagnetic theory and not enough to empirical inquiry.
Looking for litterature on the subject of forces and momentum in electromagnetic systems, I have found this article dated from october 2002 : "On an Additional Magnetic Force Present in a System of Coaxial Solenoids", http://pdf.lu/72oA (http://pdf.lu/72oA). The conclusion of this paper is the following :That was written 13 years ago. Can you hear the crickets?QuoteMore generally, experiments to validate or disconfirm, in suitable geometries, the various terms of our proposed generalized equation of motion (7) would evidently be desirable. The Lorentz force is the only one of those terms currently known beyond doubt to be physically valid. For a century too much has been left to accepted electromagnetic theory and not enough to empirical inquiry.
Phenomenology and empirical investigation seem well today be the future of electromagnetism !
NSF-1701 Update 8/11/15. Assembly of frustum complete. Final weigh-in 2.383 kg. (grill) Thermometer installed, thanks to an idea from a pal here on NSF. Electrodes (solid copper wire) and terminal strip attached. Frustum is pictured upside down, as test will have small end closest to floor.Now the NSF-1701 looks like a very important part of the NCC-1701 ;D ;)
Final assembly on microwave (oven) controller just about done. Terminal strip on back and all wired up. Outside case reinstalled, fan and turntable motor disabled. All that's left is to attach copper wire and galinstan copper cups.
Just about at the end of the build phase!!!!!!!!!!!
Shell your bearing is able to produce a lot of friction.. ???Two balance points for me.(http://www.brainyquote.com/photos/c/charlescalebcolton203963.jpg)Same as mine, 3 blades, 2 balance points.OK. I now understand the double knife edge (actually triple).About PaulTheSwag's experiment:
1. What differentiates the thrust profile from one where only an initial impulse was produced?
2. What is a "double knife-edge fulcrum"? It makes no sense to me.
3. Do we know the power value?
2. Did you saw the pictures? http://imgur.com/a/iO7er
.......Dr. Rodal,
Clearly, the geometrical attenuation γ(r) is much greater for the Yang cavity at 15 ° and closer to the vertex than the previously calculated for 6 ° and farther from the vertex . When the attenuation gradient is correctly calculated, the attenuation is clearly greater for higher angles and closer to the vertex.
........
To do it right I should couple the small endplate externally to the large with ceramic rods, avoiding the issue of the cavity walls heating and changing length. Then I'll free float the plate in the small end, therefor the expanding side walls will just slide on by the plate and not change the distance between the plates, thereby keeping Q and mode. I grok this...
... Another idea that's been knocking around in my skull for a while would be to fabricate a frustum shaped block out of a high-k ceramic and then plate the whole thing... ???Do we have and orde of magnitude for the Q reduction due to copper oxydation by the oxygen of air ?
...Shell your bearing is able to produce a lot of friction.. ???
Two balance points for me.
What do you think about commercial bearings for your carbon construction? metal, plastic or ceramic
.......Dr. Rodal,
Clearly, the geometrical attenuation γ(r) is much greater for the Yang cavity at 15 ° and closer to the vertex than the previously calculated for 6 ° and farther from the vertex . When the attenuation gradient is correctly calculated, the attenuation is clearly greater for higher angles and closer to the vertex.
........
For a while i was wondering what you were doing as I did not understand the purpose of the graphs, but your last explanation made it clear for me. Thanks for that....
As you have the opportunity now to calculate the attenuation gradient for a half cone angle, do you think it is possible to investigate if there is an optimal angle?
fe, calculate the gamma for each 5° incremental to see how the attenuation evolves through the different angles? Does attenuation continue to increase with the increasing angle or is there an optimum angle?
Information like this would be crucial for redesigning frustums to achieve max attenuation and would consequently assist in answering the question to what gives the most net force result in a frustum : a high Q, or a high attenuation or maybe, as Todd previously suggested, Q and attenuation needs to balance each other?
We continue our calculations of the gamma function γ as a measure of exponential geometrical attenuation:
Eθ = A e - γ r
where the gamma function γ(r) (which cannot be expressed in terms of any known function appearing in any textbook), has to be obtained as a numerical solution to the differential equation
r dγ/dr + γ = - (1/Eθ)*dEθ/dr
for what we think is most likely the Yang EM Drive geometry:
bigDiameter = 0.247 (*meter*);
smallDiameter = 0.1144253 (*meter*);
axialLength = 0.24 (*meter*);
r1 = 0.211022 (*meter*);
r2 = 0.455515 (*meter*);
θ = 15.44 °
We show below:
1) γ(r) vs. r for TE011 to max attenuation of 5
2) γ(r) vs. r for TE011 to max attenuation of 25
3) Eθ/A vs. r for TE011
Clearly, the geometrical attenuation γ(r) is much greater for the Yang cavity at 15 ° and smaller distance to the vertex than the previously calculated for 6 ° and larger distance to the vertex
We continue by showing γ for the Yang cavity at 15 ° to the previously calculated for 6 ° side by side.
1) The 6 ° Yang/Shell geometry:
bigDiameter = 0.201(*meter*);
smallDiameter = 0.1492(*meter*);
axialLength = 0.24(*meter*);
r1 = 0.693281 (*meter*); (*spherical small radius *)
r2 = 0.933978 (*meter*); (*spherical large radius *)
θw = 6.15933 ° (*degrees*); (*half-cone angle*)
2) The 15 ° Yang EM Drive geometry:
bigDiameter = 0.247 (*meter*);
smallDiameter = 0.1144253 (*meter*);
axialLength = 0.24 (*meter*);
r1 = 0.211022 (*meter*);
r2 = 0.455515 (*meter*);
θw = 15.44 ° (*degrees*); (*half-cone angle*)
the geometry we consider is as shown in this image:
(http://gregegan.customer.netspace.net.au/SCIENCE/Cavity/CavityShape.gif)
We show below:
1) γ(r) vs. r for TE011 15 ° geometry
2) γ(r) vs. r for TE011 6 ° geometry
Clearly, the geometrical attenuation γ(r) is much greater for the Yang cavity at 15 ° and closer to the vertex than the previously calculated for 6 ° and farther from the vertex . When the attenuation gradient is correctly calculated, the attenuation is clearly greater for higher angles and closer to the vertex.
__________________________
These are calculations of the gamma function γ as a measure of exponential geometrical attenuation:
Eθ = A e - γ r
where the gamma function γ(r) (which cannot be expressed in terms of any known function appearing in any textbook), has to be obtained as a numerical solution to the differential equation
r dγ/dr + γ = - (1/Eθ)*dEθ/dr
...By that conclusion, we can practically guarantee that a smaller cone angle will have a higher Q, because the loss due to attenuation is much smaller.
FYI: What you're doing makes a lot more sense to me than what Z&F were showing. No wonder I was having such a difficult time interpreting their results.
Now, my question is, was Yang right when she said that the more cylindrical frustum with higher Q had the greatest thrust? Shell may do better than we expect with her 6-deg. frustum, but not because of what we thought we knew 2 months ago.
Todd
It could if I wasn't using a trick here that I needed to mention and I'm really sorry it slipped my mind. The knife edge really isn't a knife edge anymore, it has been rounded off using a belt sander and the tube simply rolls over the rounded surface of the blade that was a sharp edge.Shell your bearing is able to produce a lot of friction.. ???Two balance points for me.(http://www.brainyquote.com/photos/c/charlescalebcolton203963.jpg)Same as mine, 3 blades, 2 balance points.OK. I now understand the double knife edge (actually triple).About PaulTheSwag's experiment:
1. What differentiates the thrust profile from one where only an initial impulse was produced?
2. What is a "double knife-edge fulcrum"? It makes no sense to me.
3. Do we know the power value?
2. Did you saw the pictures? http://imgur.com/a/iO7er
What do you think about commercial bearings for your carbon construction? metal, plastic or ceramic
@Dr. Rodal ("And/Or curious others")
Would you be able to produce output using the tool or formula of your choice at your leisure to see how relative humidity might impact results?
If you already know. Please don't waste your time.
I just am curious that I have not seen any mention about RH having any cause or effect or that the impact of RH differences are so small, that they don't need to be considered.
With the large differences in thrust results for tests done in a vacuum compared to testing under normal atmospheric pressure conditions. I've been wondering if RH could be a major contributing cause to those differences.
Thanks
Don
...By that conclusion, we can practically guarantee that a smaller cone angle will have a higher Q, because the loss due to attenuation is much smaller.
FYI: What you're doing makes a lot more sense to me than what Z&F were showing. No wonder I was having such a difficult time interpreting their results.
Now, my question is, was Yang right when she said that the more cylindrical frustum with higher Q had the greatest thrust? Shell may do better than we expect with her 6-deg. frustum, but not because of what we thought we knew 2 months ago.
Todd
Actually, calculating the Q factor as
qualityFactor = (2/skinDepth)*(energyVolumeIntegral/energySurfaceIntegral)
results in slightly higher Q for the 15 degree geometry than for the 6 degree geometry:
Mode shape TE012
Q (6 degree geometry) = 71,173
Q (15 degree geometry) = 73,658
using resistivity = 1.678*10^(-8)(*copper*);
(For impure copper or other alloys the Q will decrease with the increasing resistivity)
And a calculation for TheTraveller's 30 degree geometry showed a theoretical Q near 100,000
So, calculating
qualityFactor = (2/skinDepth)*(energyVolumeIntegral/energySurfaceIntegral)
although higher angles result in greater attenuation, the Q actually goes up rather than down because less of the energy is exposed to the surface
Everything I have looked at so far consistently points toward higher cone angles and being closer to the vertex as being better, which is agreement with Shawyer's, McCulloch's and Notsosureofit's formulas.
(As long as there is an electromagnetic field mode shape filling the cavity towards the small base: extending the cone with a mode that doesn't reach the small base is wasted volume: it results in lower Q)
TE modes have higher Q than TM modes.
___________________
1) The 6 ° Yang/Shell geometry:
bigDiameter = 0.201(*meter*);
smallDiameter = 0.1492(*meter*);
axialLength = 0.24(*meter*);
r1 = 0.693281 (*meter*); (*spherical small radius *)
r2 = 0.933978 (*meter*); (*spherical large radius *)
θw = 6.15933 ° (*degrees*); (*half-cone angle*)
2) The 15 ° Yang EM Drive geometry:
bigDiameter = 0.247 (*meter*);
smallDiameter = 0.1144253 (*meter*);
axialLength = 0.24 (*meter*);
r1 = 0.211022 (*meter*);
r2 = 0.455515 (*meter*);
θw = 15.44 ° (*degrees*); (*half-cone angle*)
@Dr. Rodal ("And/Or curious others")
Would you be able to produce output using the tool or formula of your choice at your leisure to see how relative humidity might impact results?
If you already know. Please don't waste your time.
I just am curious that I have not seen any mention about RH having any cause or effect or that the impact of RH differences are so small, that they don't need to be considered.
With the large differences in thrust results for tests done in a vacuum compared to testing under normal atmospheric pressure conditions. I've been wondering if RH could be a major contributing cause to those differences.
Thanks
Don
Hi, I have not taken the time to consider how to calculate how humidity may affect the results. I agree that it sounds very interesting for many reasons. For example, we know how microwave ovens preferentially excite a water molecule and they mostly heat food by heating water, so moist air is most relevant. I would have to think about how to include that effect in calculations :)
For the time being it would be useful if experimenters would record and report the relative humidity of the environment when they performed their tests.
Good points Don, nice post.@Dr. Rodal ("And/Or curious others")
Would you be able to produce output using the tool or formula of your choice at your leisure to see how relative humidity might impact results?
If you already know. Please don't waste your time.
I just am curious that I have not seen any mention about RH having any cause or effect or that the impact of RH differences are so small, that they don't need to be considered.
With the large differences in thrust results for tests done in a vacuum compared to testing under normal atmospheric pressure conditions. I've been wondering if RH could be a major contributing cause to those differences.
Thanks
Don
Hi, I have not taken the time to consider how to calculate how humidity may affect the results. I agree that it sounds very interesting for many reasons. For example, we know how microwave ovens preferentially excite a water molecule and they mostly heat food by heating water, so moist air is most relevant. I would have to think about how to include that effect in calculations :)
For the time being it would be useful if experimenters would record and report the relative humidity of the environment when they performed their tests.
Another sign of getting older. Sigh.....
I forgot to mention, that we also used both horizontal and vertical polarity with our microwave antennas for diversity. In some cases vertical or horizontal polarities made major differences with different atmospheric conditions.
Antennas which received our microwave signals ("Using tropospheric scatter") were as much as 400 miles away. So there were multiple weather conditions which our microwave transmission could encounter to reach our distant ends.
I have no idea if this applies to EM Drives or not.
But I am surprised that there has been little test data to compare when a waveguide is used to inject the microwave signal into the EM Drive if the waveguide was in a horizontal or vertical mounting position on the EM Drive and if the polarity of that waveguide, could have any effect on measured results when using the same sized EM Drive with the opposite polarity to compare horizontal to vertical polarities. Near or about at the same mounting position.
I'm not sure if any of your test tools or formulas allow waveguides to use horizontal or vertical polarities as input data to see if any polarity differences might make the output of same, have different results.
Don
@Dr. Rodal ("And/Or curious others")
Would you be able to produce output using the tool or formula of your choice at your leisure to see how relative humidity might impact results?
If you already know. Please don't waste your time.
I just am curious that I have not seen any mention about RH having any cause or effect or that the impact of RH differences are so small, that they don't need to be considered.
With the large differences in thrust results for tests done in a vacuum compared to testing under normal atmospheric pressure conditions. I've been wondering if RH could be a major contributing cause to those differences.
Thanks
Don
Hi, I have not taken the time to consider how to calculate how humidity may affect the results. I agree that it sounds very interesting for many reasons. For example, we know how microwave ovens preferentially excite a water molecule and they mostly heat food by heating water, so moist air is most relevant. I would have to think about how to include that effect in calculations :)
For the time being it would be useful if experimenters would record and report the relative humidity of the environment when they performed their tests.
For a non-sealed EMDrive cavity that's exposed to the air, any humidity in the cavity will heat up and vent out of any openings- including wave-guides and wiring harnesses, but eventually, it'll all be gone, so the longer the magnetron is turned on, the more steam will evaporate and escape. Any anomalous thrust would tend towards zero over time because of humidity as the device clears out the water vapor in the form of pressurized steam.
For an EMDrive operated in a vacuum, any humidity would get flushed out as the pump reduces the air pressure inside the chamber.
For a "perfectly" sealed EM Drive, the steam would build up pressure inside the EMDrive as energy is added to the system, but no thrust would be measured external to the system. Until, of course, the balloon pops.
NSF-1701 live test...Galinstan ordered and should be here within a week. Will do the live test either 8/18 or 8/25 depending on the delivery.
Good points Don, nice post.@Dr. Rodal ("And/Or curious others")
Would you be able to produce output using the tool or formula of your choice at your leisure to see how relative humidity might impact results?
If you already know. Please don't waste your time.
I just am curious that I have not seen any mention about RH having any cause or effect or that the impact of RH differences are so small, that they don't need to be considered.
With the large differences in thrust results for tests done in a vacuum compared to testing under normal atmospheric pressure conditions. I've been wondering if RH could be a major contributing cause to those differences.
Thanks
Don
Hi, I have not taken the time to consider how to calculate how humidity may affect the results. I agree that it sounds very interesting for many reasons. For example, we know how microwave ovens preferentially excite a water molecule and they mostly heat food by heating water, so moist air is most relevant. I would have to think about how to include that effect in calculations :)
For the time being it would be useful if experimenters would record and report the relative humidity of the environment when they performed their tests.
Another sign of getting older. Sigh.....
I forgot to mention, that we also used both horizontal and vertical polarity with our microwave antennas for diversity. In some cases vertical or horizontal polarities made major differences with different atmospheric conditions.
Antennas which received our microwave signals ("Using tropospheric scatter") were as much as 400 miles away. So there were multiple weather conditions which our microwave transmission could encounter to reach our distant ends.
I have no idea if this applies to EM Drives or not.
But I am surprised that there has been little test data to compare when a waveguide is used to inject the microwave signal into the EM Drive if the waveguide was in a horizontal or vertical mounting position on the EM Drive and if the polarity of that waveguide, could have any effect on measured results when using the same sized EM Drive with the opposite polarity to compare horizontal to vertical polarities. Near or about at the same mounting position.
I'm not sure if any of your test tools or formulas allow waveguides to use horizontal or vertical polarities as input data to see if any polarity differences might make the output of same, have different results.
Don
Ok... this is from a gal who though she knew something about antennas and I'd like your input because I found out I really don't. I would guess over the last couple months this group has dug into antennas quite deep and I've read more about them than I care to think of. Weird and beautiful stuff.
A couple of things that are on the the forefront that to me have seemed to be of importance.
First off is the radiation patterns and how they must be aligned correctly to excite one or the other, TE or TM mode pattern in the frustum.
Second is the radiation pattern needs to be as uniform as it can, with no funny lobes. A simple snub @ 2.45GHz in a TE insertion point towards the bottom leads to rotational effects of the modes around the cavity. As they build and collapse it kills off the Q of the cavity.
Third is the losses associated with an antenna into the cavity. We have calculated only 40-50 watts of effective RF being available to cause a thrust effect in the cavity.
Fourth that low output is why many (Including me) have elected to treat the Frustum like part of a waveguide and directly inject the output of a magnetron down a waveguide into the cavity. rfmwguy coupled his magnetron directly into his cavity, the man is awsum.
I am a Newbie and a lurker I bow to all of you for your unbounded enthusiasm and hardwork. While I am not a DIYer, I have been following with all the DIY projects. I have a humble suggestion.
I was changing the parameters in the McCalloch Thrust calculation Spreadsheet. (Excellent work!)
By having the same power and changing the geometry and size of the frustum, more than 1 N can be achived, it looks like.
(Changed based on Juan 2 corrected values)
Updated
Input Reference Value
Big Diameter 28
Small Diameter 1
Cavity Length 100
Q 5000
Frequency 2.45
Power 1000
Big Radius 14
Small Radius 0.5
mN Force 1608.75
mN Force 1081.08
mN Force 1025.45
This could prove the validity of McCalloch calculations.
Just a humble suggestion.
Yes, I think I can record on Ustream as I do it. If I cannot, I'll simply do a recorded video.NSF-1701 live test...Galinstan ordered and should be here within a week. Will do the live test either 8/18 or 8/25 depending on the delivery.
I think X_Ray asked this earlier but I didn't see your response: do you have any plans to record your tests, so people who aren't able to watch it live can still watch the video? (Depending on what streaming program you're using, this may be a built-in function.)
...
Note: I just can't help having "flashbacks" to my U.S. Air Force days as a Wideband Communications Equipment 304x0 equipment repair person (http://oai.dtic.mil/oai/oai?verb=getRecord&metadataPrefix=html&identifier=ADA201690) in the 1970's who maintained microwave equipment using near these same microwave frequencies.
One of my many maintenance duties was to replace desiccant in every waveguide we used and it was not simply to avoid only rust and/or condensation, in those waveguides.
It has been awhile. But I think one of the reasons why we used desiccant and replaced it so often in all our waveguides had to do with standing waves. I could be remembering this incorrectly. But that's what I recall today. That said. The situation I am referencing was at a site where our microwave transmit power was 10 KW per 60 foot parabolic antenna. Shown below.
Don
...
Note: I just can't help having "flashbacks" to my U.S. Air Force days as a Wideband Communications Equipment 304x0 equipment repair person (http://oai.dtic.mil/oai/oai?verb=getRecord&metadataPrefix=html&identifier=ADA201690) in the 1970's who maintained microwave equipment using near these same microwave frequencies.
One of my many maintenance duties was to replace desiccant in every waveguide we used and it was not simply to avoid only rust and/or condensation, in those waveguides.
It has been awhile. But I think one of the reasons why we used desiccant and replaced it so often in all our waveguides had to do with standing waves. I could be remembering this incorrectly. But that's what I recall today. That said. The situation I am referencing was at a site where our microwave transmit power was 10 KW per 60 foot parabolic antenna. Shown below.
Don
I would suspect the main reason was to prevent arcing in the waveguide. It's pretty common to find desiccant in the X band aircraft weather radars operating above 6-7 KW but not in the lower powered ones...
So what did you use? Just a bag of desiccant sitting in the wave guide? How big?
Frustumapaloosa?! :DYes, I think I can record on Ustream as I do it. If I cannot, I'll simply do a recorded video.NSF-1701 live test...Galinstan ordered and should be here within a week. Will do the live test either 8/18 or 8/25 depending on the delivery.
I think X_Ray asked this earlier but I didn't see your response: do you have any plans to record your tests, so people who aren't able to watch it live can still watch the video? (Depending on what streaming program you're using, this may be a built-in function.)
The stiction at initial movement is inherent for any conventional bearing. Rounded blades will work better i think, use a drop of oil and all will be good :)It could if I wasn't using a trick here that I needed to mention and I'm really sorry it slipped my mind. The knife edge really isn't a knife edge anymore, it has been rounded off using a belt sander and the tube simply rolls over the rounded surface of the blade that was a sharp edge.Shell your bearing is able to produce a lot of friction.. ???Two balance points for me.(http://www.brainyquote.com/photos/c/charlescalebcolton203963.jpg)Same as mine, 3 blades, 2 balance points.OK. I now understand the double knife edge (actually triple).About PaulTheSwag's experiment:
1. What differentiates the thrust profile from one where only an initial impulse was produced?
2. What is a "double knife-edge fulcrum"? It makes no sense to me.
3. Do we know the power value?
2. Did you saw the pictures? http://imgur.com/a/iO7er
What do you think about commercial bearings for your carbon construction? metal, plastic or ceramic
I liked the strength of the blade but I disliked the friction and stresses when using 2 blades one on top of each other or the way the blade could slice into a metal or a carbon fiber tube. In testing I had the blades chip and shatter against each other and glued steel plates end up getting a grove from the blade in just a couple runs up and down with weights on the fulcrum.
A mental calculation thinking about the small radii the tube would roll over changing the length over 1 meter was around 5 microns. It's acceptable.
Added: What do you think xray? Do you think this will work ok? I wanted to try and avoid any bearing for they seem to always have the issued of initial movement from stiction.
I am a Newbie and a lurker I bow to all of you for your unbounded enthusiasm and hardwork. While I am not a DIYer, I have been following with all the DIY projects. I have a humble suggestion.
I was changing the parameters in the McCalloch Thrust calculation Spreadsheet. (Excellent work!)
By having the same power and changing the geometry and size of the frustum, more than 1 N can be achived, it looks like.
(Changed based on Juan 2 corrected values)
Updated
Input Reference Value
Big Diameter 28
Small Diameter 1
Cavity Length 100
Q 5000
Frequency 2.45
Power 1000
Big Radius 14
Small Radius 0.5
mN Force 1608.75
mN Force 1081.08
mN Force 1025.45
This could prove the validity of McCalloch calculations.
Just a humble suggestion.
There you go...might be as interesting as most the stuff on basic cable ;)Frustumapaloosa?! :DYes, I think I can record on Ustream as I do it. If I cannot, I'll simply do a recorded video.NSF-1701 live test...Galinstan ordered and should be here within a week. Will do the live test either 8/18 or 8/25 depending on the delivery.
I think X_Ray asked this earlier but I didn't see your response: do you have any plans to record your tests, so people who aren't able to watch it live can still watch the video? (Depending on what streaming program you're using, this may be a built-in function.)
If the timing's right, you, Shells and TT could put on a show!
I'm pushing as hard as I can. ;)Frustumapaloosa?! :DYes, I think I can record on Ustream as I do it. If I cannot, I'll simply do a recorded video.NSF-1701 live test...Galinstan ordered and should be here within a week. Will do the live test either 8/18 or 8/25 depending on the delivery.
I think X_Ray asked this earlier but I didn't see your response: do you have any plans to record your tests, so people who aren't able to watch it live can still watch the video? (Depending on what streaming program you're using, this may be a built-in function.)
If the timing's right, you, Shells and TT could put on a show!
[quote author=TheUberOverLord link=topic=38203.msg1415594#msg1415594Your flexible cone is a good idea i think!
Should have said insertion points for the waveguide instead.
Each will excite a different mode.
Top magnetron
Side magnetron waveguide
Dual Dipoles top
http://www.hep.ucl.ac.uk/~jolly/thesis/figures/sw-structure.jpg
Opposing RF injection points
http://cas.web.cern.ch/cas/Germany2009/Lectures/PDF-Web/Jensen.pdfIt's a very nice read. Notice that, because the R,L,C components in the cavity model are in shunt configuration, the usual expression for Q is reciprocated (e.g. Q = R/(w L) ). Also note that maximum attainable Q's (non-superconducting) are pegged around 41,000.
Back to the grind
good reading...
The file looks good! Thanks for the quotehttp://cas.web.cern.ch/cas/Germany2009/Lectures/PDF-Web/Jensen.pdfIt's a very nice read. Notice that, because the R,L,C components in the cavity model are in shunt configuration, the usual expression for Q is reciprocated (e.g. Q = R/(w L) ). Also note that maximum attainable Q's (non-superconducting) are pegged around 41,000.
Back to the grind
good reading...
So what did you use? Just a bag of desiccant sitting in the wave guide? How big?
http://cas.web.cern.ch/cas/Germany2009/Lectures/PDF-Web/Jensen.pdfIt's a very nice read. Notice that, because the R,L,C components in the cavity model are in shunt configuration, the usual expression for Q is reciprocated (e.g. Q = R/(w L) ). Also note that maximum attainable Q's (non-superconducting) are pegged around 41,000.
Back to the grind
good reading...
By the way those of you supporting the EM drive want an example of a theory that started out on the fringes but has gradually moved more centre wise then they only have to look at holographic theory for the universe.
http://www.sciencedaily.com/releases/2015/04/150427101633.htm
Actually, no. They are separate. But note that they are not mutually exclusive 8)By the way those of you supporting the EM drive want an example of a theory that started out on the fringes but has gradually moved more centre wise then they only have to look at holographic theory for the universe.
http://www.sciencedaily.com/releases/2015/04/150427101633.htm
Is that theory the one that leads down the path to... everything around us including us is just a simulation.
Interesting Russian EMDrive like patent:
http://bankpatentov.ru/node/123593
and comment received on Reddit EMDrive forum:
https://www.reddit.com/r/EmDrive/comments/3ceyjv/email_from_roger_shawyer/ctww6rd
As Dr. Vladimir Leonov claims the "Shawyer Effect" works via the QV, Dr. White might be interested.
I keep thinking about the idea (http://forum.nasaspaceflight.com/index.php?topic=37642.msg1412971#msg1412971) I had a few days ago and pushed it further. I thought about Rodal and WarpTech's advice of increasing cone angle and keeping the apex as near as possible of the small end. I also kept Shawyer's high Df and concentric spherical ends to maintain a high Q, and I've ended up with this wide and shallow resonant design, with incredible large spherical ends, making the frustum almost a half-sphere:
Db = 600 mm
Ds = 150 mm
L = 51.20 mm
r1 = 76.92 mm
r2 = 307.67 mm
r2-r1 = 230.75 mm
θ = 77.18°
Resonance at 2.45 GHz in TE013 mode, Df = 0.96
Would be a challenge to build but nevertheless interesting to test. What could be the Q of such a cavity?
That's an interesting shape!
How did you calculate <<Resonance at 2.45 GHz in TE013 mode>> ?
It is quite an interesting shape to explore for example whether there is a limit to the notion of large angles and proximity to the base. I will calculate the attenuation shape, Q and resonance when I have a chance :)That's an interesting shape!
How did you calculate <<Resonance at 2.45 GHz in TE013 mode>> ?
Thanks doc!
I used TheTraveller's latest's spreadsheet (http://emdrive.wiki/Useful_EMDrive_Design_and_Test_Tools) to tune the various dimensions. I do not know any software or technique to do those calcs.
Sorry for crashing in but I must ask.From what I have seen, a neon tube must be almost in contact with the source. Not a good idea.
Is Neon light usefull for detecting RF leaks outside frustum?
Sorry if it`s been proposed.
Keep up, we are counting on you! :)
Looks like I am going to be interviewed on a live radio talk show about my NSF-1701 experiment in the near future. When it becomes finalized, I'll post the info I have. Can't discuss any details yet...
They always said I had a Face made for the Radio ;)
Some of these images seem wrong.Dr. Rodal,
I was trying to figure out a way to communicate what I thought was going on, but I think I was wrong. It's simple -
Draw 3 sine waves on a sheet of paper, x-y axis, each symmetric about the x axis, but with different amplitudes. Then draw horizontal lines tangent to the extreme positive and negative values of each sine wave. I used the y value of the top and bottom horizontal line.
So the weaker sign waves are not clipped, they just don't have enough power to show up on the scale of the strongest.
I'll see about using a different color map.
bluered (opaque blue to transparent white to opaque red). I have several color maps available, this is just the first try. I personally don't like it very much.
I keep thinking about the idea (http://forum.nasaspaceflight.com/index.php?topic=37642.msg1412971#msg1412971) I had a few days ago and pushed it further. I thought about Rodal and WarpTech's advice of increasing cone angle and keeping the apex as near as possible of the small end. I also kept Shawyer's high Df and concentric spherical ends to maintain a high Q, and I've ended up with this wide and shallow resonant design, with incredible large spherical ends, making the frustum almost a half-sphere:
Db = 600 mm
Ds = 150 mm
L = 51.20 mm
r1 = 76.92 mm
r2 = 307.67 mm
r2-r1 = 230.75 mm
θ = 77.18°
Resonance at 2.45 GHz in TE013 mode, Df = 0.96
Would be a challenge to build but nevertheless interesting to test. What could be the Q of such a cavity?
I keep thinking about the idea (http://forum.nasaspaceflight.com/index.php?topic=37642.msg1412971#msg1412971) I had a few days ago and pushed it further. I thought about Rodal and WarpTech's advice of increasing cone angle and keeping the apex as near as possible of the small end. I also kept Shawyer's high Df and concentric spherical ends to maintain a high Q, and I've ended up with this wide and shallow resonant design, with incredible large spherical ends, making the frustum almost a half-sphere:
Db = 600 mm
Ds = 150 mm
L = 51.20 mm
r1 = 76.92 mm
r2 = 307.67 mm
r2-r1 = 230.75 mm
θ = 77.18°
Resonance at 2.45 GHz in TE013 mode, Df = 0.96
Would be a challenge to build but nevertheless interesting to test. What could be the Q of such a cavity?
Some of these images seem wrong.Dr. Rodal,
I was trying to figure out a way to communicate what I thought was going on, but I think I was wrong. It's simple -
Draw 3 sine waves on a sheet of paper, x-y axis, each symmetric about the x axis, but with different amplitudes. Then draw horizontal lines tangent to the extreme positive and negative values of each sine wave. I used the y value of the top and bottom horizontal line.
So the weaker sign waves are not clipped, they just don't have enough power to show up on the scale of the strongest.
I'll see about using a different color map.
bluered (opaque blue to transparent white to opaque red). I have several color maps available, this is just the first try. I personally don't like it very much.
Example:
bighz
(http://forum.nasaspaceflight.com/xindex.php,qaction=dlattach,3Btopic=38203.0,3Battach=1055446,3Bimage.pagespeed.ic.JnWBLMhTwp.webp)
as I interpret this, it is the Hz field, the magnetic field normal to the Big Base
the magnetic field normal to a surface should be zero at a surface. It should be zero at the Big Base.
It is close to zero when I post-process the csv files with Wolfram Mathematica
Yet in the above images you show this bighz as having the highest magnitude magnetic field at the Big Base?
Ditto for smallhz
(http://forum.nasaspaceflight.com/xindex.php,qaction=dlattach,3Btopic=38203.0,3Battach=1055434,3Bimage.pagespeed.ic.1L14N7WegQ.webp)
That's a fact...he just called and said it might be tonight...will call me back in abt 1 hr. Love to have you there as well. Told them my belief was seeing is believing...not willing to take others word on it. had to try it for myself.Looks like I am going to be interviewed on a live radio talk show about my NSF-1701 experiment in the near future. When it becomes finalized, I'll post the info I have. Can't discuss any details yet...
They always said I had a Face made for the Radio ;)
I just asked him for details and I might do it with you. No weirdness and space aliens allowed. ;)
That's a fact...he just called and said it might be tonight...will call me back in abt 1 hr. Love to have you there as well. Told them my belief was seeing is believing...not willing to take others word on it. had to try it for myself.Looks like I am going to be interviewed on a live radio talk show about my NSF-1701 experiment in the near future. When it becomes finalized, I'll post the info I have. Can't discuss any details yet...
They always said I had a Face made for the Radio ;)
I just asked him for details and I might do it with you. No weirdness and space aliens allowed. ;)
I suppose that rfmwguy is the legal owner of whatever he produces, including what he speaks and articulates.That's a fact...he just called and said it might be tonight...will call me back in abt 1 hr. Love to have you there as well. Told them my belief was seeing is believing...not willing to take others word on it. had to try it for myself.Looks like I am going to be interviewed on a live radio talk show about my NSF-1701 experiment in the near future. When it becomes finalized, I'll post the info I have. Can't discuss any details yet...
They always said I had a Face made for the Radio ;)
I just asked him for details and I might do it with you. No weirdness and space aliens allowed. ;)
Don't suppose we'll be able to listen or you record? Likely will be copyrighted.
Will be talking NSF-1701 on art bells dark matters digital radio network tomorrow at midnight PST.
Guest info to appear tomorrow abt 7:30 PM on othersideofmidnight.com website
Show is a mixture of science fiction, fantasy and science fact...I'll stay with facts and hope to still be entertaining, but understand its show biz. Will not over promise and under deliver however ;)
Its late for sure but they archive shows. Will talk how and why I jumped in and where it could lead.
Sounds like fun...
Course my reply would be I will believe it when I see it personally ;)Will be talking NSF-1701 on art bells dark matters digital radio network tomorrow at midnight PST.
Guest info to appear tomorrow abt 7:30 PM on othersideofmidnight.com website
Show is a mixture of science fiction, fantasy and science fact...I'll stay with facts and hope to still be entertaining, but understand its show biz. Will not over promise and under deliver however ;)
Its late for sure but they archive shows. Will talk how and why I jumped in and where it could lead.
Sounds like fun...
Even money says Art brings up UFO's in the first 5 min.
Be prepared what to answer if he asks you:Course my reply would be I will believe it when I see it personally ;)Will be talking NSF-1701 on art bells dark matters digital radio network tomorrow at midnight PST.
Guest info to appear tomorrow abt 7:30 PM on othersideofmidnight.com website
Show is a mixture of science fiction, fantasy and science fact...I'll stay with facts and hope to still be entertaining, but understand its show biz. Will not over promise and under deliver however ;)
Its late for sure but they archive shows. Will talk how and why I jumped in and where it could lead.
Sounds like fun...
Even money says Art brings up UFO's in the first 5 min.
Sorta the reason I started my build...
Be prepared what to answer if he asks you:Art has been doing this a long time. Surely he knows the UFOs use Zero time zero space motion frozen 500KV (DC) repulsive electrostatic counter rotating vortexes in glass and copper plate capacitors radially around a central magnetic generator. Everyone knows that, right?*
1) Whether Shawyer invented the EM Drive as a result of a close encounter of the 3rd kind with UFO's that allowed him to get access to UFO's propulsion technology?
...
Some of these images seem wrong.
Example:
bighz
(http://forum.nasaspaceflight.com/xindex.php,qaction=dlattach,3Btopic=38203.0,3Battach=1055446,3Bimage.pagespeed.ic.JnWBLMhTwp.webp)
as I interpret this, it is the Hz field, the magnetic field normal to the Big Base
the magnetic field normal to a surface should be zero at a surface. It should be zero at the Big Base.
It is close to zero when I post-process the csv files with Wolfram Mathematica
Yet in the above images you show this bighz as having the highest magnitude magnetic field at the Big Base?
Ditto for smallhz
(http://forum.nasaspaceflight.com/xindex.php,qaction=dlattach,3Btopic=38203.0,3Battach=1055434,3Bimage.pagespeed.ic.1L14N7WegQ.webp)
Interesting - We'll need to wait until Imbfan gets the automated field intensity extraction software running. That won't be to long based on the progress she is making.
Earlier today I was looking at the field intensity of the images around the base ends using hdfview. It seems clear from looking at adjacent slices that something may be not right. See the attached jpgs for z slice 14, 15, 16 and 17. Slice z-14 is within the metal, so nothing. Slice z-15 is the cut we have been taking as at the big base, while z-16 is one pixel inward and z-17 is 2 pixels inward. With the lattice measuring 0.275 meters (rounded up in deference to DeltaMass) and resolution 250, the distance between pixels is 1.1 mm so z-15 should be well out of the metal if z-14 is the metal surface. But the images seem to say that z-14 is well inside the metal and z-15 is somewhere close to the surface while z-16 is well outside the metal.
I wonder if the meep "subpixel averaging" is blending the dielectric constant at the edge of the metal with the air, also at the edge? If so, maybe I should quit using "subpixel averaging." On the other hand, the characteristic you wrote about above seems different than the one I observed.
Let's see what it looks like when the field intensities are automatically and correctly extracted for the images. Then we'll have something that we can fix, if it is broken. Fixing my fat fingers is much more difficult and they are not even broken - yet :o
P.S. I see you looked at this while I was typing.
The ranges are from field components as follows:
# hx all data range from -0.000538633 to 0.000538633. H field big end
Interesting - We'll need to wait until Imbfan gets the automated field intensity extraction software running. That won't be to long based on the progress she is making.
I wonder if the meep "subpixel averaging" is blending the dielectric constant at the edge of the metal with the air, also at the edge? If so, maybe I should quit using "subpixel averaging." On the other hand, the characteristic you wrote about above seems different than the one I observed.
I keep thinking about the idea (http://forum.nasaspaceflight.com/index.php?topic=37642.msg1412971#msg1412971) I had a few days ago and pushed it further. I thought about Rodal and WarpTech's advice of increasing cone angle and keeping the apex as near as possible of the small end. I also kept Shawyer's high Df and concentric spherical ends to maintain a high Q, and I've ended up with this wide and shallow resonant design, with incredible large spherical ends, making the frustum almost a half-sphere:
Db = 600 mm
Ds = 150 mm
L = 51.20 mm
r1 = 76.92 mm
r2 = 307.67 mm
r2-r1 = 230.75 mm
θ = 77.18°
Resonance at 2.45 GHz in TE013 mode, Df = 0.96
Would be a challenge to build but nevertheless interesting to test. What could be the Q of such a cavity?
Glad you found the spreadsheet useful. Using Goal Seek has made it super fast to find the exact resonance in the desired mode or not.
Interesting design.
As I understand the momenta gradient driven opposite Frustum movement and resultant Force vectors, they "PUSH" the frustum from the outer big end edge toward the vertex. Would not this design result in a lot of Force vectors pushing toward the vertex but not really helping axial Force generation so much?
It is quite an interesting shape to explore for example whether there is a limit to the notion of large angles and proximity to the base. I will calculate the attenuation shape, Q and resonance when I have a chance :)
Interesting - We'll need to wait until Imbfan gets the automated field intensity extraction software running. That won't be to long based on the progress she is making.
Please find a python file attached. It works well on my machine using the flags presented before. There remain some rough edges, but this should do the bulk of the work automagically. Enjoy!QuoteI wonder if the meep "subpixel averaging" is blending the dielectric constant at the edge of the metal with the air, also at the edge? If so, maybe I should quit using "subpixel averaging." On the other hand, the characteristic you wrote about above seems different than the one I observed.
I'm pretty sure this is exactly what is happening. The boundary lies between pixels 14 and 16. It's late otherwise I'd math it out. If you don't subpixel average, the angled sides would go wonky, I bet.
The ranges are from field components as follows:
# hx all data range from -0.000538633 to 0.000538633. H field big end
Lol...I've thought about that. Tho it will be my chance to get realistic conversation going, like let's get more data before we talk about a jetsons lifestyle ;)Be prepared what to answer if he asks you:Course my reply would be I will believe it when I see it personally ;)Will be talking NSF-1701 on art bells dark matters digital radio network tomorrow at midnight PST.
Guest info to appear tomorrow abt 7:30 PM on othersideofmidnight.com website
Show is a mixture of science fiction, fantasy and science fact...I'll stay with facts and hope to still be entertaining, but understand its show biz. Will not over promise and under deliver however ;)
Its late for sure but they archive shows. Will talk how and why I jumped in and where it could lead.
Sounds like fun...
Even money says Art brings up UFO's in the first 5 min.
Sorta the reason I started my build...
1) Whether Shawyer invented the EM Drive as a result of a close encounter of the 3rd kind with UFO's that allowed him to get access to UFO's propulsion technology?
2) Whether the EM Drive is derived from Die Glocke Wunderwaffe antigravity research from WWII ?
3) What are you going to do if you accidentally create a wormhole in your garage as a result of your EM Drive research
4) if the EM Drive works, how long will a trip to Alpha Centauri take.
:)
Here are the two png sets scaled to the maximum range of the E and H fields for the t=0 time slice. The ranges are from field components as follows:
# ez all data range from -0.000245405 to 0.000245405. E field big end
# hx all data range from -0.000538633 to 0.000538633. H field big end
# ez all data range from -4.04811e-05 to 4.04811e-05. E field small end
# hy all data range from -0.000287974 to 0.000287974. H field small end
Please look these png's over closely to be sure that this is what you want to see as it will be considerable effort to scale the png files in this way for the general case.
Or do you need to see the side views for this t = 0 case?
...
They look like ContourPlots in Mathematica when I use PlotRange with a range smaller than the full magnitude, so the contours get cliped. I would double check whether magnitudes have not been clipped.
3) Is there some means to control the number of contour values in the contour plots? It looks to me like there are more contour levels than the number of colors available, as a result colors keep repeating themselves. What one wants is to have blue represent the lowest magnitude and red the highest magnitude, instead of red/green/blue/yellow patterns being repeated cyclically.
Meep adventurers may wish to consider improving h5topng to produce images which contain: - The numerical value on the contour boundaries
http://www.enterprisemission.com/Lol...I've thought about that. Tho it will be my chance to get realistic conversation going, like let's get more data before we talk about a jetsons lifestyle ;)Be prepared what to answer if he asks you:Course my reply would be I will believe it when I see it personally ;)Will be talking NSF-1701 on art bells dark matters digital radio network tomorrow at midnight PST.
Guest info to appear tomorrow abt 7:30 PM on othersideofmidnight.com website
Show is a mixture of science fiction, fantasy and science fact...I'll stay with facts and hope to still be entertaining, but understand its show biz. Will not over promise and under deliver however ;)
Its late for sure but they archive shows. Will talk how and why I jumped in and where it could lead.
Sounds like fun...
Even money says Art brings up UFO's in the first 5 min.
Sorta the reason I started my build...
1) Whether Shawyer invented the EM Drive as a result of a close encounter of the 3rd kind with UFO's that allowed him to get access to UFO's propulsion technology?
2) Whether the EM Drive is derived from Die Glocke Wunderwaffe antigravity research from WWII ?
3) What are you going to do if you accidentally create a wormhole in your garage as a result of your EM Drive research
4) if the EM Drive works, how long will a trip to Alpha Centauri take.
:)
Will be talking NSF-1701 on art bells dark matters digital radio network tomorrow at midnight PST.
I keep thinking about the idea (http://forum.nasaspaceflight.com/index.php?topic=37642.msg1412971#msg1412971) I had a few days ago and pushed it further. I thought about Rodal and WarpTech's advice of increasing cone angle and keeping the apex as near as possible of the small end. I also kept Shawyer's high Df and concentric spherical ends to maintain a high Q, and I've ended up with this wide and shallow resonant design, with incredible large spherical ends, making the frustum almost a half-sphere:
Yes.Will be talking NSF-1701 on art bells dark matters digital radio network tomorrow at midnight PST.
PST? Did you mean midnight Pacific Daylight Time?
Yes, PDT, 3 hours behind ESTWill be talking NSF-1701 on art bells dark matters digital radio network tomorrow at midnight PST.
PST? Did you mean midnight Pacific Daylight Time?
.................How did you determine the very wide angle for this setup?
Db = 600 mm
Ds = 150 mm
L = 51.20 mm
r1 = 76.92 mm
r2 = 307.67 mm
r2-r1 = 230.75 mm
θ = 77.18°
Resonance at 2.45 GHz in TE013 mode, Df = 0.96
.....
Yes. Every force vector in an EmDrive with spherical ends has an inner component (yet the vector on the axis) since they all point towards the vertex. With a side wall angle > 45° this component is maybe too much. Maybe the wall would need to be less angled.
Whatever, I did that to explore "extreme shapes" and these kinds of possibilities:
Please take a look at the conclusion of the below paper, it may explain why we have a decreasing force in vacuum.I like this.... Thanks for the post.
When the particles in air (water,soot...) disappear the force decrease. What do you think of that? It could be an explanation for the thin shell frustums.
Lateral Chirality-sorting Optical Spin Forces in Evanescent Fields
http://arxiv.org/abs/1408.2268
"The transverse component of the spin angular momentum of evanescent waves gives rise to lateral optical forces on chiral particles, which have the unusual property of acting in a direction in which there is neither a field gradient nor wave propagation."
LATE NITE, past my bedtime. :)Yes, PDT, 3 hours behind ESTWill be talking NSF-1701 on art bells dark matters digital radio network tomorrow at midnight PST.
PST? Did you mean midnight Pacific Daylight Time?
How did you determine the very wide angle for this setup?
If the attenuation keeps growing with the angle, you would end up with 90° half-cone angle, which doesn't make sense.
Mine too, but I'll revert back to my college days one more time ;)LATE NITE, past my bedtime. :)Yes, PDT, 3 hours behind ESTWill be talking NSF-1701 on art bells dark matters digital radio network tomorrow at midnight PST.
PST? Did you mean midnight Pacific Daylight Time?
Well you're younger than I am kiddo. ;) 60...HA!Mine too, but I'll revert back to my college days one more time ;)LATE NITE, past my bedtime. :)Yes, PDT, 3 hours behind ESTWill be talking NSF-1701 on art bells dark matters digital radio network tomorrow at midnight PST.
PST? Did you mean midnight Pacific Daylight Time?
I keep thinking about the idea (http://forum.nasaspaceflight.com/index.php?topic=37642.msg1412971#msg1412971) I had a few days ago and pushed it further. I thought about Rodal and WarpTech's advice of increasing cone angle and keeping the apex as near as possible of the small end. I also kept Shawyer's high Df and concentric spherical ends to maintain a high Q, and I've ended up with this wide and shallow resonant design, with incredible large spherical ends, making the frustum almost a half-sphere:
Db = 600 mm
Ds = 150 mm
L = 51.20 mm
r1 = 76.92 mm
r2 = 307.67 mm
r2-r1 = 230.75 mm
θ = 77.18°
Resonance at 2.45 GHz in TE013 mode, Df = 0.96
Would be a challenge to build but nevertheless interesting to test. What could be the Q of such a cavity?
I might be able to model it. Can you export an STL of the part?
Too bad if you dont skype in...they mentioned they'd like to get more perspectives on builders and I mentioned you. Think if people hear realistic, serious stories on theory and build, it'll let them know its not a fringe element working on these things. Right now, my thought is many think it is another cold-fusion type device. Lots of notions to clear up. Seems like a good place to start...Well you're younger than I am kiddo. ;) 60...HA!Mine too, but I'll revert back to my college days one more time ;)LATE NITE, past my bedtime. :)Yes, PDT, 3 hours behind ESTWill be talking NSF-1701 on art bells dark matters digital radio network tomorrow at midnight PST.
PST? Did you mean midnight Pacific Daylight Time?
If I wake up early I might join in but don't count your chickens.
I keep thinking about the idea (http://forum.nasaspaceflight.com/index.php?topic=37642.msg1412971#msg1412971) I had a few days ago and pushed it further. I thought about Rodal and WarpTech's advice of increasing cone angle and keeping the apex as near as possible of the small end. I also kept Shawyer's high Df and concentric spherical ends to maintain a high Q, and I've ended up with this wide and shallow resonant design, with incredible large spherical ends, making the frustum almost a half-sphere:
Db = 600 mm
Ds = 150 mm
L = 51.20 mm
r1 = 76.92 mm
r2 = 307.67 mm
r2-r1 = 230.75 mm
θ = 77.18°
Resonance at 2.45 GHz in TE013 mode, Df = 0.96
Would be a challenge to build but nevertheless interesting to test. What could be the Q of such a cavity?
I might be able to model it. Can you export an STL of the part?
Although SketchUp is not good at all with circles (it draws them as a series of segments) I updated the number of segments per circle from 24 to 240 in order to improve precision.
I don't know if you need the 2D plan or the 3D modeled object, so I created both versions and exported them in STL format. You can find them zipped below.
Although SketchUp is not good at all with circles (it draws them as a series of segments) I updated the number of segments per circle from 24 to 240 in order to improve precision.
I don't know if you need the 2D plan or the 3D modeled object, so I created both versions and exported them in STL format. You can find them zipped below.
I keep thinking about the idea (http://forum.nasaspaceflight.com/index.php?topic=37642.msg1412971#msg1412971) I had a few days ago and pushed it further. I thought about Rodal and WarpTech's advice of increasing cone angle and keeping the apex as near as possible of the small end. I also kept Shawyer's high Df and concentric spherical ends to maintain a high Q, and I've ended up with this wide and shallow resonant design, with incredible large spherical ends, making the frustum almost a half-sphere:
Db = 600 mm
Ds = 150 mm
L = 51.20 mm
r1 = 76.92 mm
r2 = 307.67 mm
r2-r1 = 230.75 mm
θ = 77.18°
Resonance at 2.45 GHz in TE013 mode, Df = 0.96
Would be a challenge to build but nevertheless interesting to test. What could be the Q of such a cavity?
I might be able to model it. Can you export an STL of the part?
Although SketchUp is not good at all with circles (it draws them as a series of segments) I updated the number of segments per circle from 24 to 240 in order to improve precision.
I don't know if you need the 2D plan or the 3D modeled object, so I created both versions and exported them in STL format. You can find them zipped below.
This is a very interesting shape to test the outer limits of the theories and methods involved.
Due to the extreme spherical conical shape of this cavity, the limitations of the spreadsheet approach (that in a kludgy way intends to model a sherical cone as a large series of cylinders) is more crudely exposed:
the natural frequency of mode TE013 is 2.132 GHz (instead of 2.45 GHz), a difference of 15% in frequency (for cone angles of 15 degrees the spreadsheet is 1 to 2% different from the exact solution)
It does resonate, and it resonates well:
theoretical Q = 94,254
using a resistivity = 1.678*10^(-8)(*copper*) (Q will go down with increasing resitivity materials and geometrical imperfections)
although this is not much more than the Q calculated for the 30 degrees cavity, so it looks like there are diminishing returns after 30 degrees
I attach below the contour plots for
1) the magnetic field in the spherical radial direction
2) the electric field in the azimuthal circumferential direction
Note how distorted is the magnetic field in the spherical radial direction
theoretical Q = 94,254
using a resistivity = 1.678*10^(-8)(*copper*) (Q will go down with increasing resitivity materials and geometrical imperfections)
Welcome to the forum !Quote from: Rodaltheoretical Q = 94,254
using a resistivity = 1.678*10^(-8)(*copper*) (Q will go down with increasing resitivity materials and geometrical imperfections)
Hello sir.
I'm just lurking here. Appreciation for all the work you sir and all you guys do for emdive community.
What if the the copper cavity is cooled down with liquid Nitrogen?
How does it affect the Q-factor in real?
Could the inner portion of the cavity be lined with YBCO thin film and N2 cooled? Does YBCO film do the job at 2.3G or 23G freq?
Best, Peter
...For the 30 degree superconducting cavity Shawyer is entering asymmetrically from the lateral conical surface:
what would be the best placement for the waveguide entrance then?
What if the the copper cavity is cooled down with liquid Nitrogen?
How does it affect the Q-factor in real?
Wow this is like a mishmash of @Notsosureofit and @Mike McCulloch. It even has a tapered waveguide. Very excited to read this closely later.
http://arxiv.org/abs/physics/0606072
Electromagnetic Relativity Drive
Alan Duncan: To ask the Secretary of State for Trade and Industry how much his Department has provided to the electromagnetic relativity drive design proposed by Roger Shawyer; and from what budget funding has been drawn. [103254]
Margaret Hodge [holding answer 27 November 2006]: Awards have been made to Satellite Propulsion Research Ltd from the DTI’s Small Firms and Enterprise budget.
July 2001—£43,809 paid.
A feasibility study into the application of innovative microwave thruster technology for satellite propulsion. The study involved development of an experimental thruster followed by independent tests and evaluation
August 2003—£81,291 total grant awarded, £68,399 paid to date.
A follow-on from the above project, to design and develop a demonstration model engine. To be tested on a dynamic test rig, to demonstrate continuous thrust and the conversion of thrust into kinetic energy.
Both grants were awarded against the criteria of the DTI’s Smart scheme that was designed to help fund pioneering and risky R and D projects in small and medium enterprises.
Highly qualified technical experts and academics carried out an assessment on behalf of the Department.
Seems the UK gov's panel of highly qualified technical experts and academic experts agree Shawyer's Experimental and Demonstrator EMDrives work as claimed.
Seems the UK gov's panel of highly qualified technical experts and academic experts agree Shawyer's Experimental and Demonstrator EMDrives work as claimed.
Long time lurker here, but to me this statement is not what the link you quote states at all. It states only that technical and academic experts carried out an assessment of the claims and were involved with the tests. At no point does it state what the result of that review was.
What if the the copper cavity is cooled down with liquid Nitrogen?
How does it affect the Q-factor in real?
I wonder this exactly since the beginning. After proving this technology is genuine (we're not sure for now) I think we could get high thrust from a cooled frustum, not necessarily superconducting, but just copper cooled with liquid nitrogen. I don't know if the Q would increase (?) but the power could certainly ramp up.
TT's spreadsheet, from Shawyer's advice and using Shawyer's thrust formulae, predict above 1.2 N of force for 2 kW of input power by a design similar to the one I've posted. Yang already used 2.5 kW on a non-superconducting, non-cooled copper frustum in ambient air. So with liquid nitrogen we could go way beyond that!
The results was SPR got the funding from the UK gov to both build the Experimental EMDrive and the later much more complex Demonstrator EMDrive and the rotary test rig.
More data here attached. Pages 10 - 14.
What if the the copper cavity is cooled down with liquid Nitrogen?
How does it affect the Q-factor in real?
I wonder this exactly since the beginning. After proving this technology is genuine (we're not sure for now) I think we could get high thrust from a cooled frustum, not necessarily superconducting, but just copper cooled with liquid nitrogen. I don't know if the Q would increase (?) but the power could certainly ramp up.
Wow this is like a mishmash of @Notsosureofit and @Mike McCulloch. It even has a tapered waveguide. Very excited to read this closely later.
http://arxiv.org/abs/physics/0606072
Good post. One of the things I will try and explain on the radio show tonight is the amount of quality information out there is small and should not be taken at face value. More test data is needed, there is no disputing this. For those qualified to build and test, its imperative we collect as much info as possible. Spent decades in Marketing...I know how to "wordsmith" and always avoided it, for it might fool some of the people some of the time, but in the long run makes a person, business or institution look foolish.Seems the UK gov's panel of highly qualified technical experts and academic experts agree Shawyer's Experimental and Demonstrator EMDrives work as claimed.
Long time lurker here, but to me this statement is not what the link you quote states at all. It states only that technical and academic experts carried out an assessment of the claims and were involved with the tests. At no point does it state what the result of that review was.
What if the the copper cavity is cooled down with liquid Nitrogen?
How does it affect the Q-factor in real?
I wonder this exactly since the beginning. After proving this technology is genuine (we're not sure for now) I think we could get high thrust from a cooled frustum, not necessarily superconducting, but just copper cooled with liquid nitrogen. I don't know if the Q would increase (?) but the power could certainly ramp up.
As I understand it Q is proportional to power stored/power dissipated. A big part of the Power dissipated on the bottom of the fraction is from electrical resistance of the resonator walls. The increase in Q in superconducting cavities is because the resistance of the superconductor goes to zero, making the bottom of the fraction tiny.
Pure Copper is not a superconductor at liquid nitrogen temperatures. Its resistance decreases as it cools, but not by a huge amount. The internet [1] says its temperature coefficient is 3.9x10-3/1 degree C. So the 220 degree swing from a lab to liquid nitrogen temperatures only cuts the resistance by about half. I have to caveat this that I am assuming the temperature curve is linear. That assumption should be verified. If that assumption is right and if the majority of the losses in your cavity are from electrical resistance then you could theoretically double your Q.
...
Oh No - Hoaxland :(I'm more concerned abt getting the word out abt serious work, pro and con, on this global project...outside the veil of corporate and government secrecy. Internet collaboration is what makes this different from most efforts. Want to emphasize that to whomever will listen.
Good luck with that.
I trust you're well aware of the kind of stuff that man has tried to foist on people over these many years.
http://www.badastronomy.com/bad/misc/hoagland/
Are you sure?
I might be mistaken, but from what that calculator says the swing from 20C down to -195.79C cut the copper resistance by a factor of 6.
As you mentioned before, assuming the temperature curve is linear as shown in the graph below.
The graph also indicates the resistivity of Cu at 77K ramps down to that region.
So, the Q factor can be doubled. Actually can be multiplied by 2.45, which is huge.
Quote from: ElizabethGreene...So the 220 degree swing from a lab to liquid nitrogen temperatures only cuts the resistance by about half. I have to caveat this that I am assuming the temperature curve is linear. That assumption should be verified. If that assumption is right and if the majority of the losses in your cavity are from electrical resistance then you could theoretically double your Q.
Are you sure?
I might be mistaken, but from what that calculator says the swing from 20C down to -195.79C cut the copper resistance by a factor of 6.
As you mentioned before, assuming the temperature curve is linear as shown in the graph below.
The graph also indicates the resistivity of Cu at 77K ramps down to that region.
So, the Q factor can be doubled. Actually can be multiplied by 2.45, which is huge.
No, I'm not sure at all and I defer. I was lazy and used the hyperphysics calculator. Only now do I notice that it contradicts itself. It says that 250 ohms at 20 C is 40.3ohms at -195C, but 40.3 ohms at -195C is 74ohms at 20C. It does the same weird bit using 63 and 278K as well. Broken?
I theorise that the same is happening within the frustum with the traveling waves. We build up a DC magnetic component in the walls from the harmonic mode and when the mode collapses (they all have in every simulation) to form another mode. That switch decaying produces evanescent waves that push into the copper ~5um imparting momentum and force on the still decaying magnetic component left from the last mode.
Shell
I'm more concerned abt getting the word out abt serious work, pro and con, on this global project...outside the veil of corporate and government secrecy. Internet collaboration is what makes this different from most efforts. Want to emphasize that to whomever will listen.
Dr. Rodal,For some of the pics there seems to be a weak coupling of TE31 eigenvalue
New png files are uploaded for the 64 cycle Shell 2d loop antenna case. I put up the new csv files as well but they "should" be identical to the previous ones. The png files are named slightly differently than previously so I uploaded them into the existing folders. You won't have any difficulty telling the difference visually, but of course your computer will. I have attached one of the new files here just so all can see the effect of changing the scaling range. And note that the pixel grid separation is exactly the same, 1.1 mm while 1/20th of the length of the frustum is about 12 mm.
Still haven't made your x-30 slice that you asked for a few days ago. Will get it up soon.
https://drive.google.com/folderview?id=0B1XizxEfB23tfmVCZlhnNUVtTGRoTTlZSGJiT3ZfSHBvYnNELUc1WlN0Sk15ZDZud3pSWmM&usp=sharing (https://drive.google.com/folderview?id=0B1XizxEfB23tfmVCZlhnNUVtTGRoTTlZSGJiT3ZfSHBvYnNELUc1WlN0Sk15ZDZud3pSWmM&usp=sharing)
I was pleasantly surprised at how concisely and accurately Hoagland could express himself when he wanted to. He'd obviously done a fair bit of research on the topic and had his duckies in a row there. All the more cognitively dissonant, therefore, when he claims he sees artificial structures on practically every body in the solar system 8).I'm more concerned abt getting the word out abt serious work, pro and con, on this global project...outside the veil of corporate and government secrecy. Internet collaboration is what makes this different from most efforts. Want to emphasize that to whomever will listen.
Hoagland! Boy you walked into that one! ;) But actually he was pretty good at helping to describe the em drive. Very interesting show! Hope you decide to go back on Dave! Nice radio voice too! ;D
Have been intrigued by this topic, but was daunted by trying to wade through all 4 threads. The show was an excellent introduction.
Am dismayed by the apparent lack of theory about how or why this thing works, if it does. I'm reminded of the difference between Edison and Tesla. Edison was the tinkerer who didn't really understand what he was doing, and didn't really care as long as the invention worked. Tesla, on the other hand was the theoretician who was able to progress by leaps and bounds on the basis of his (mostly) sound understanding of the theory.
What do you guys think?
Dr. Rodal,
New png files are uploaded for the 64 cycle Shell 2d loop antenna case. I put up the new csv files as well but they "should" be identical to the previous ones. The png files are named slightly differently than previously so I uploaded them into the existing folders. You won't have any difficulty telling the difference visually, but of course your computer will. I have attached one of the new files here just so all can see the effect of changing the scaling range. And note that the pixel grid separation is exactly the same, 1.1 mm while 1/20th of the length of the frustum is about 12 mm.
Still haven't made your x-30 slice that you asked for a few days ago. Will get it up soon.
https://drive.google.com/folderview?id=0B1XizxEfB23tfmVCZlhnNUVtTGRoTTlZSGJiT3ZfSHBvYnNELUc1WlN0Sk15ZDZud3pSWmM&usp=sharing (https://drive.google.com/folderview?id=0B1XizxEfB23tfmVCZlhnNUVtTGRoTTlZSGJiT3ZfSHBvYnNELUc1WlN0Sk15ZDZud3pSWmM&usp=sharing)
Dr. Rodal,For some of the pics there seems to be a weak coupling of TE31 eigenvalue
New png files are uploaded for the 64 cycle Shell 2d loop antenna case. I put up the new csv files as well but they "should" be identical to the previous ones. The png files are named slightly differently than previously so I uploaded them into the existing folders. You won't have any difficulty telling the difference visually, but of course your computer will. I have attached one of the new files here just so all can see the effect of changing the scaling range. And note that the pixel grid separation is exactly the same, 1.1 mm while 1/20th of the length of the frustum is about 12 mm.
Still haven't made your x-30 slice that you asked for a few days ago. Will get it up soon.
https://drive.google.com/folderview?id=0B1XizxEfB23tfmVCZlhnNUVtTGRoTTlZSGJiT3ZfSHBvYnNELUc1WlN0Sk15ZDZud3pSWmM&usp=sharing (https://drive.google.com/folderview?id=0B1XizxEfB23tfmVCZlhnNUVtTGRoTTlZSGJiT3ZfSHBvYnNELUc1WlN0Sk15ZDZud3pSWmM&usp=sharing)
(I get ~2.39GHz for TE311 and ~2.63GHz for TE312, hope i didn't make a mistake! p=1 and p=2 are very close... Rechecked numbers are welcome).
Most interesting is that the whole run looks like coupling to different modes at different time steps inclusive target mode TE012 (TE31p,TM112?)
I read this paper by Lars Johansson for his Masters of Science at the Lund Institute in Sweden a couple months ago and stuck it in the back of my mind maybe to be used later. You see I remember years and years ago in school seeing the submarine effect of the pointed copper wire in a mercury trough. We were asked to speculate why it moved. I remember writing a little paper on the resistivity of copper being less than the mercury and considering electrons always took the path of less resistance you would see this effect. The electrons flowing along the walls of the sub submerged in the mercury would take the path of the copper because of the lower resistance and flow faster in the copper sub inducing a magnetic field in the copper that would act with the currents flowing in the mercury pushing it forward. I got a C on the paper. Not my finest hour, but I was learning, oh geez I still am learning.
I theorise that the same is happening within the frustum with the traveling waves. We build up a DC magnetic component in the walls from the harmonic mode and when the mode collapses (they all have in every simulation) to form another mode. That switch decaying produces evanescent waves that push into the copper ~5um imparting momentum and force on the still decaying magnetic component left from the last mode.
Shell
Another explanation would be perhaps with longitudinal ampere force [EDIT]If such a thing really exist (see below and try to take a look at the preview not only the abstract, it is striking, kind of frustum shape ;) ):
http://rd.springer.com/article/10.1140%2Fepjp%2Fi2014-14034-2
I'm more concerned abt getting the word out abt serious work, pro and con, on this global project...outside the veil of corporate and government secrecy. Internet collaboration is what makes this different from most efforts. Want to emphasize that to whomever will listen.
Hoagland! Boy you walked into that one! ;) But actually he was pretty good at helping to describe the em drive. Very interesting show! Hope you decide to go back on Dave! Nice radio voice too! ;D
Have been intrigued by this topic, but was daunted by trying to wade through all 4 threads. The show was an excellent introduction.
Am dismayed by the apparent lack of theory about how or why this thing works, if it does. I'm reminded of the difference between Edison and Tesla. Edison was the tinkerer who didn't really understand what he was doing, and didn't really care as long as the invention worked. Tesla, on the other hand was the theoretician who was able to progress by leaps and bounds on the basis of his (mostly) sound understanding of the theory.
What do you guys think?
Dr. Rodal,For some of the pics there seems to be a weak coupling of TE31 eigenvalue
New png files are uploaded for the 64 cycle Shell 2d loop antenna case. I put up the new csv files as well but they "should" be identical to the previous ones. The png files are named slightly differently than previously so I uploaded them into the existing folders. You won't have any difficulty telling the difference visually, but of course your computer will. I have attached one of the new files here just so all can see the effect of changing the scaling range. And note that the pixel grid separation is exactly the same, 1.1 mm while 1/20th of the length of the frustum is about 12 mm.
Still haven't made your x-30 slice that you asked for a few days ago. Will get it up soon.
https://drive.google.com/folderview?id=0B1XizxEfB23tfmVCZlhnNUVtTGRoTTlZSGJiT3ZfSHBvYnNELUc1WlN0Sk15ZDZud3pSWmM&usp=sharing (https://drive.google.com/folderview?id=0B1XizxEfB23tfmVCZlhnNUVtTGRoTTlZSGJiT3ZfSHBvYnNELUc1WlN0Sk15ZDZud3pSWmM&usp=sharing)
(I get ~2.39GHz for TE311 and ~2.63GHz for TE312, hope i didn't make a mistake! p=1 and p=2 are very close... Rechecked numbers are welcome).
Most interesting is that the whole run looks like coupling to different modes at different time steps inclusive target mode TE012 (TE31p,TM112?)
TE 114 is also nearby. Mode superposition/competition(/degenerative mode shape) could lead to interesting effects.Dr. Rodal,For some of the pics there seems to be a weak coupling of TE31 eigenvalue
New png files are uploaded for the 64 cycle Shell 2d loop antenna case. I put up the new csv files as well but they "should" be identical to the previous ones. The png files are named slightly differently than previously so I uploaded them into the existing folders. You won't have any difficulty telling the difference visually, but of course your computer will. I have attached one of the new files here just so all can see the effect of changing the scaling range. And note that the pixel grid separation is exactly the same, 1.1 mm while 1/20th of the length of the frustum is about 12 mm.
Still haven't made your x-30 slice that you asked for a few days ago. Will get it up soon.
https://drive.google.com/folderview?id=0B1XizxEfB23tfmVCZlhnNUVtTGRoTTlZSGJiT3ZfSHBvYnNELUc1WlN0Sk15ZDZud3pSWmM&usp=sharing (https://drive.google.com/folderview?id=0B1XizxEfB23tfmVCZlhnNUVtTGRoTTlZSGJiT3ZfSHBvYnNELUc1WlN0Sk15ZDZud3pSWmM&usp=sharing)
(I get ~2.39GHz for TE311 and ~2.63GHz for TE312, hope i didn't make a mistake! p=1 and p=2 are very close... Rechecked numbers are welcome).
Most interesting is that the whole run looks like coupling to different modes at different time steps inclusive target mode TE012 (TE31p,TM112?)
Yes! Great observation. This is another reason I want to excite in the TE012 mode! We've got something like 5 modes through that frequency spread around 2.45GHz... TE312, TE212, TE411, TE311, TE012. Hard to read the chart unless you sharpen the image.
This is the one difference between a circular waveguide and a conical frustum is the excited modes coupling effects causing mode switching and the mode shifting and decaying into the small end (seen the reverse also happen but because it was at the start of some of the meep multicolor flashing Tie-dyed runs a couple months ago they could be in question).
Shell
I still need to build a couple of stands yet, the materials that were going to be picked up yesterday by a friend with a truck didn't make it. He was worried that the heavy rains we had would ruin the melamine sheets, he was right. Getting them today and will start putting together the stands for the graph-stand and the digital scales. Still waiting for some hardware to get here from China... It has to be on a slow boat.TE 114 is also nearby. Mode superposition/competition could lead to interesting effects.Dr. Rodal,For some of the pics there seems to be a weak coupling of TE31 eigenvalue
New png files are uploaded for the 64 cycle Shell 2d loop antenna case. I put up the new csv files as well but they "should" be identical to the previous ones. The png files are named slightly differently than previously so I uploaded them into the existing folders. You won't have any difficulty telling the difference visually, but of course your computer will. I have attached one of the new files here just so all can see the effect of changing the scaling range. And note that the pixel grid separation is exactly the same, 1.1 mm while 1/20th of the length of the frustum is about 12 mm.
Still haven't made your x-30 slice that you asked for a few days ago. Will get it up soon.
https://drive.google.com/folderview?id=0B1XizxEfB23tfmVCZlhnNUVtTGRoTTlZSGJiT3ZfSHBvYnNELUc1WlN0Sk15ZDZud3pSWmM&usp=sharing (https://drive.google.com/folderview?id=0B1XizxEfB23tfmVCZlhnNUVtTGRoTTlZSGJiT3ZfSHBvYnNELUc1WlN0Sk15ZDZud3pSWmM&usp=sharing)
(I get ~2.39GHz for TE311 and ~2.63GHz for TE312, hope i didn't make a mistake! p=1 and p=2 are very close... Rechecked numbers are welcome).
Most interesting is that the whole run looks like coupling to different modes at different time steps inclusive target mode TE012 (TE31p,TM112?)
Yes! Great observation. This is another reason I want to excite in the TE012 mode! We've got something like 5 modes through that frequency spread around 2.45GHz... TE312, TE212, TE411, TE311, TE012. Hard to read the chart unless you sharpen the image.
This is the one difference between a circular waveguide and a conical frustum is the excited modes coupling effects causing mode switching and the mode shifting and decaying into the small end (seen the reverse also happen but because it was at the start of some of the meep multicolor flashing Tie-dyed runs a couple months ago they could be in question).
Shell
The later interpretation don't will be easier with such complex EM messy mix.
All here lurking for your experimental data :)
Here are the last 14 time step images for the Poynting vector field distribution through the trapezium plane with normal y of the Yang/Shell 6 degree cone angle truncated cone, excited with a 2 parallel dipole antennas near the Small Base.Interesting! Looks like strong vector component always into the direction of the small diameter..
There is a strong Poynting vector oriented from the big base (at the bottom of the images) to the small base (at the top of the images).
__________________________________________________________________
Meep data
Yang-Shell model - 64 cycle run
SeeShell's conic frustum model using 2 parallel dipoles, 0.55 wavelength from and parallel to the small end, 0.9 wavelength long and 1 wavelength apart. Centrally located with middle at axis of asy-symmetry of cone.
z axis = axis of axy-symmetry
(set! fsi 2.45E+009 ) ; Drive frequency, in SI units, Hz.
(set! bigdia 11.01) ; ID - inches
(set! smalldia 6.25) ; ID - inches
(set! high 10.2) ; length - inches
Source excitation magnetic component Hz.
Run length - 64 full cycles
Time slices output for each field component:
every 1/10-th cycle from 62.7 cycles to 64 cycles (end of run)
run 0 finished at t = 13.054 (6527 timesteps) - Resolution = 250
230x196x196x14 is .h5 files dimensions.
End cuts are at: Big end -- .h5 row 15 Small end -- .h5 row 214
Note: Resonant frequency calculated by meep is 2.463GHz
NSF handle_aero__ Date of upload. 8/6/2015
Thanks DM, I immediately thought of you when he mentioned how skeptics and believers got along so well here. I tried to say that it was a productive thing to have that occur...with civility. Yes,were are some things he talked about before I came on that would question, but its show biz and gets people wondering...I was pleasantly surprised at how concisely and accurately Hoagland could express himself when he wanted to. He'd obviously done a fair bit of research on the topic and had his duckies in a row there. All the more cognitively dissonant, therefore, when he claims he sees artificial structures on practically every body in the solar system 8).I'm more concerned abt getting the word out abt serious work, pro and con, on this global project...outside the veil of corporate and government secrecy. Internet collaboration is what makes this different from most efforts. Want to emphasize that to whomever will listen.
Hoagland! Boy you walked into that one! ;) But actually he was pretty good at helping to describe the em drive. Very interesting show! Hope you decide to go back on Dave! Nice radio voice too! ;D
Have been intrigued by this topic, but was daunted by trying to wade through all 4 threads. The show was an excellent introduction.
Am dismayed by the apparent lack of theory about how or why this thing works, if it does. I'm reminded of the difference between Edison and Tesla. Edison was the tinkerer who didn't really understand what he was doing, and didn't really care as long as the invention worked. Tesla, on the other hand was the theoretician who was able to progress by leaps and bounds on the basis of his (mostly) sound understanding of the theory.
What do you guys think?
I'm glad Dave made the point that there isn't one theory that explains EmDrive - I believe that to be a fair representation of the situation. As for the convection issue - well, let's just say it might be problematic, but let's wait and see what the data says.
Thanks DM, I immediately thought of you when he mentioned how skeptics and believers got along so well here. I tried to say that it was a productive thing to have that occur...with civility. Yes,were are some things he talked about before I came on that would question, but its show biz and gets people wondering...I was pleasantly surprised at how concisely and accurately Hoagland could express himself when he wanted to. He'd obviously done a fair bit of research on the topic and had his duckies in a row there. All the more cognitively dissonant, therefore, when he claims he sees artificial structures on practically every body in the solar system 8).I'm more concerned abt getting the word out abt serious work, pro and con, on this global project...outside the veil of corporate and government secrecy. Internet collaboration is what makes this different from most efforts. Want to emphasize that to whomever will listen.
Hoagland! Boy you walked into that one! ;) But actually he was pretty good at helping to describe the em drive. Very interesting show! Hope you decide to go back on Dave! Nice radio voice too! ;D
Have been intrigued by this topic, but was daunted by trying to wade through all 4 threads. The show was an excellent introduction.
Am dismayed by the apparent lack of theory about how or why this thing works, if it does. I'm reminded of the difference between Edison and Tesla. Edison was the tinkerer who didn't really understand what he was doing, and didn't really care as long as the invention worked. Tesla, on the other hand was the theoretician who was able to progress by leaps and bounds on the basis of his (mostly) sound understanding of the theory.
What do you guys think?
I'm glad Dave made the point that there isn't one theory that explains EmDrive - I believe that to be a fair representation of the situation. As for the convection issue - well, let's just say it might be problematic, but let's wait and see what the data says.
All in all, it was as expected...fun. Actually the 2 hours seemed to fly by. I knew this was the first radio chat about the emdrive, so I tried to keep it as general as I could. Thanks for the comments and for staying up late 8)
Dr. Rodal,
I generated and uploaded a z-30 slice to 64 cycle Shell-2D-loop-ant, z-30-csvs and z-30-pngs. Your current link should work so tell me if it doesn't.
I want to thank Imbfan for all of the hard work of automating the generation of these files. I don't think it could have been done manually. Thank you Imbfan.
aero
It would be very nice if it was possible to download a podcast or get a link so we who couldn't listen live also could hear it.
Looks like all shows are digitally archived and can be listened to anytime. Think you have to sign up for access. Not sure the procedure but you might try here: http://darkmatterdigitalnetwork.com/shows/other-side-of-midnight/Thanks DM, I immediately thought of you when he mentioned how skeptics and believers got along so well here. I tried to say that it was a productive thing to have that occur...with civility. Yes,were are some things he talked about before I came on that would question, but its show biz and gets people wondering...I was pleasantly surprised at how concisely and accurately Hoagland could express himself when he wanted to. He'd obviously done a fair bit of research on the topic and had his duckies in a row there. All the more cognitively dissonant, therefore, when he claims he sees artificial structures on practically every body in the solar system 8).I'm more concerned abt getting the word out abt serious work, pro and con, on this global project...outside the veil of corporate and government secrecy. Internet collaboration is what makes this different from most efforts. Want to emphasize that to whomever will listen.
Hoagland! Boy you walked into that one! ;) But actually he was pretty good at helping to describe the em drive. Very interesting show! Hope you decide to go back on Dave! Nice radio voice too! ;D
Have been intrigued by this topic, but was daunted by trying to wade through all 4 threads. The show was an excellent introduction.
Am dismayed by the apparent lack of theory about how or why this thing works, if it does. I'm reminded of the difference between Edison and Tesla. Edison was the tinkerer who didn't really understand what he was doing, and didn't really care as long as the invention worked. Tesla, on the other hand was the theoretician who was able to progress by leaps and bounds on the basis of his (mostly) sound understanding of the theory.
What do you guys think?
I'm glad Dave made the point that there isn't one theory that explains EmDrive - I believe that to be a fair representation of the situation. As for the convection issue - well, let's just say it might be problematic, but let's wait and see what the data says.
All in all, it was as expected...fun. Actually the 2 hours seemed to fly by. I knew this was the first radio chat about the emdrive, so I tried to keep it as general as I could. Thanks for the comments and for staying up late 8)
It would be very nice if it was possible to download a podcast or get a link so we who couldn't listen live also could hear it.
Wow this is like a mishmash of @Notsosureofit and @Mike McCulloch. It even has a tapered waveguide. Very excited to read this closely later.
http://arxiv.org/abs/physics/0606072
Yes, that's exactly (same equations) how I'm trying to work out the entropy.
Looks like all shows are digitally archived and can be listened to anytime. Think you have to sign up for access. Not sure the procedure but you might try here: http://darkmatterdigitalnetwork.com/shows/other-side-of-midnight/
Here are the last 14 time step images for the Poynting vector field distribution through the trapezium plane with normal y of the Yang/Shell 6 degree cone angle truncated cone, excited with 2 parallel dipole antennas located near the Small Base.
There is a strong Poynting vector oriented from the big base (at the bottom of the images) to the small base (at the top of the images).
__________________________________________________________________
Meep data (reproduced from aero's file)
Yang-Shell model - 64 cycle run
SeeShell's conic frustum model using 2 parallel dipoles, 0.55 wavelength from and parallel to the small end, 0.9 wavelength long and 1 wavelength apart. Centrally located with middle at axis of asy-symmetry of cone.
z axis = axis of axy-symmetry
(set! fsi 2.45E+009 ) ; Drive frequency, in SI units, Hz.
(set! bigdia 11.01) ; ID - inches
(set! smalldia 6.25) ; ID - inches
(set! high 10.2) ; length - inches
Source excitation magnetic component Hz.
Run length - 64 full cycles
Time slices output for each field component:
every 1/10-th cycle from 62.7 cycles to 64 cycles (end of run)
run 0 finished at t = 13.054 (6527 timesteps) - Resolution = 250
230x196x196x14 is .h5 files dimensions.
End cuts are at: Big end -- .h5 row 15 Small end -- .h5 row 214
Note: Resonant frequency calculated by meep is 2.463GHz
NSF handle_aero__ Date of upload. 8/6/2015
Boom! We've got a good lead here imho...math.mit.edu/~stevenj/papers/JohnsonBi02.pdf
The math behind.
:)Wow this is like a mishmash of @Notsosureofit and @Mike McCulloch. It even has a tapered waveguide. Very excited to read this closely later.
http://arxiv.org/abs/physics/0606072
Yes, that's exactly (same equations) how I'm trying to work out the entropy.
Wow. That is a really great paper. A goldmine. Thanks for posting the link
Just started reading... wow. I'm going to have to read more later...math.mit.edu/~stevenj/papers/JohnsonBi02.pdf
The math behind.
:)Wow this is like a mishmash of @Notsosureofit and @Mike McCulloch. It even has a tapered waveguide. Very excited to read this closely later.
http://arxiv.org/abs/physics/0606072
Yes, that's exactly (same equations) how I'm trying to work out the entropy.
Wow. That is a really great paper. A goldmine. Thanks for posting the link
http://math.mit.edu/~stevenj/papers/JohnsonBi02.pdf
The math behind.
:)Wow this is like a mishmash of @Notsosureofit and @Mike McCulloch. It even has a tapered waveguide. Very excited to read this closely later.
http://arxiv.org/abs/physics/0606072
Yes, that's exactly (same equations) how I'm trying to work out the entropy.
Dr. Rodal:aero,
Regarding your concern that the view files seem to be incorrect. We must be more specific because it is not a meep problem. The view png files are generated as follows:
- meep, using the supplied control file, propagates the EM fields and writes the specified output to .h5 files. Then meep goes away, never to be heard from again.
- h5totxt, a different stand-alone program, reads the .h5 files by specified slice, extracts the maximum and minimum data range (saving it) and writes the slice data to the .csv files which are uploaded.
- h5topng, yet another stand-alone program, using the maximum and minimum data extracted by h5totxt above, reads the h5 files and writes the view .png files of the specified slice which are uploaded.
If it were a meep problem then the .h5 data would be wrong but the csv and png data would be consistent.
If it were an h5totxt problem the data that you generate independently of the csv files would not agree with the csv data?
If it were an h5topng problem the ... well, I think this is the place to start. But where do we start with that?
The first check that I can imagine is to verify that the maximum and minimum values per slice pulled by h5totxt are in fact the same as exist in the csv data that you use.
Another possibility is that the x and y coordinates are reversed in my meep control file but if so, the png views and the csv data should be consistent so I discount that as a source of this particular problem.
Perhaps you or others have some debug suggestions?
A new DIYer is going to resume Iulian Berca's work where it was left, with the same frustum dimensions (the latest one with the cylindrical extension) and same kind of powerful 1100W magnetron.
His nickname is SullyEmDrive on Reddit and he made a great web site:
https://sullyemdrive.wordpress.com
Dimensions of SullyEmDrive's frustum:
Db = 279 mm
Ds = 159 mm
L = 228 mm
cylindrical neck = 76 mm
The small end is tunable with an axial screw so the length between ends is adjustable from 228 to 304 mm.
Unlike Iulian who positioned the waveguide as closely as possible to the big end (see Iulian's diagram (http://www.masinaelectrica.com/wp-content/uploads/2015/05/EmDrive.jpg)) Sully positioned his more near the small end. So at full small-end extension, the waveguide will be roughly in the middle of the two end plates.
He may found resonance at TE013 and TE213 modes for various lengths. Will be interesting to measure the produced force for the two modes and see if the longer frustum length for TE013 is better (as advised by Shawyer) than TM213 mode.
It would be cool is Sully could come here on NSF to share his build, ideas and test results :) rfmwguy and others already warned him about security so I hope he will stay safe.
Dr. Rodal,For some of the pics there seems to be a weak coupling of TE31 eigenvalue
New png files are uploaded for the 64 cycle Shell 2d loop antenna case. I put up the new csv files as well but they "should" be identical to the previous ones. The png files are named slightly differently than previously so I uploaded them into the existing folders. You won't have any difficulty telling the difference visually, but of course your computer will. I have attached one of the new files here just so all can see the effect of changing the scaling range. And note that the pixel grid separation is exactly the same, 1.1 mm while 1/20th of the length of the frustum is about 12 mm.
Still haven't made your x-30 slice that you asked for a few days ago. Will get it up soon.
https://drive.google.com/folderview?id=0B1XizxEfB23tfmVCZlhnNUVtTGRoTTlZSGJiT3ZfSHBvYnNELUc1WlN0Sk15ZDZud3pSWmM&usp=sharing (https://drive.google.com/folderview?id=0B1XizxEfB23tfmVCZlhnNUVtTGRoTTlZSGJiT3ZfSHBvYnNELUc1WlN0Sk15ZDZud3pSWmM&usp=sharing)
(I get ~2.39GHz for TE311 and ~2.63GHz for TE312, hope i didn't make a mistake! p=1 and p=2 are very close... Rechecked numbers are welcome).
Most interesting is that the whole run looks like coupling to different modes at different time steps inclusive target mode TE012 (TE31p,TM112?)
...Sully positioned his more near the small end. So at full small-end extension, the waveguide will be roughly in the middle of the two end plates....From what we are learning from Meep, the best place to place the RF feed is near the big base, not at the middle and not at the small end. I initially thought it was better to have the antenna near the small end (based on several arguments). I have changed my mind based on the facts presented by multiple Meep runs.
Thats why i have sad "it looks like" at some pictures, the GIF files i build show TE012.Dr. Rodal,For some of the pics there seems to be a weak coupling of TE31 eigenvalue
New png files are uploaded for the 64 cycle Shell 2d loop antenna case. I put up the new csv files as well but they "should" be identical to the previous ones. The png files are named slightly differently than previously so I uploaded them into the existing folders. You won't have any difficulty telling the difference visually, but of course your computer will. I have attached one of the new files here just so all can see the effect of changing the scaling range. And note that the pixel grid separation is exactly the same, 1.1 mm while 1/20th of the length of the frustum is about 12 mm.
Still haven't made your x-30 slice that you asked for a few days ago. Will get it up soon.
https://drive.google.com/folderview?id=0B1XizxEfB23tfmVCZlhnNUVtTGRoTTlZSGJiT3ZfSHBvYnNELUc1WlN0Sk15ZDZud3pSWmM&usp=sharing (https://drive.google.com/folderview?id=0B1XizxEfB23tfmVCZlhnNUVtTGRoTTlZSGJiT3ZfSHBvYnNELUc1WlN0Sk15ZDZud3pSWmM&usp=sharing)
(I get ~2.39GHz for TE311 and ~2.63GHz for TE312, hope i didn't make a mistake! p=1 and p=2 are very close... Rechecked numbers are welcome).
Most interesting is that the whole run looks like coupling to different modes at different time steps inclusive target mode TE012 (TE31p,TM112?)
It is not a TE311 because TE311 has 6 poles equally spaced around the circumference and I don't see anything with 6 poles around the circumference.
Be careful with ascertaining what mode it is from the hstop images in the Meep file for this run because there are several fields that are mislabeled in these images.
Take a look instead at the raw output csv files which are fine.
Looking at the csv files it is clear that it is a TEm12 mode.
A circular cross-section should show a circular field for m=0, this is not the case because
a) cartesian coordinate fields are shown
b) the effect of the parallel 2-dipole antenna
I'm pretty sure that the mode shape is TE012 presenting a diameter indentation as an effect from the antenna.
So:
1) The good news is that aero finally succeeded in exciting a TE mode, by using a parallel 2-Dipole antenna
2) It is evident that the parallel 2-Dipole antenna severely affects the mode through the cross section, because the excitation is taking place practically like a line instead of a loop. What we learn from this is that to excite a perfect TE012 mode, a circular loop antenna is needed
Many books and articles talk about square and rectangular antennas. This is fine for rectangular cross-section cavities, but to excite a perfect mode in a circular cross-section cavity it appears that a circular loop-antenna is needed.
2) It is evident that the parallel 2-Dipole antenna severely affects the mode. What we learn from this is that to excite a perfect TE012 mode, a circular loop antenna is needed
Many books and articles talk about square and rectangular antennas. This is fine for rectangular cross-section cavities, but to excite a perfect mode in a circular cross-section cavity it appears that a circular loop-antenna is needed.
2) It is evident that the parallel 2-Dipole antenna severely affects the mode. What we learn from this is that to excite a perfect TE012 mode, a circular loop antenna is needed
Many books and articles talk about square and rectangular antennas. This is fine for rectangular cross-section cavities, but to excite a perfect mode in a circular cross-section cavity it appears that a circular loop-antenna is needed.
Like this?
Steve: The current loop antenna in the copper frustum has a 14mm OD and is made from #20 AWG magnet wire soldered to an SMA bulkhead connector. This assembly is then rotated to maximize the S11 return loss for a given resonant frequency while using an RG-142 SMA-to-SMA coaxial cable run, which is typically 2.0 feet long. Location is on the frustum sidewall 1.35 inch up from the interior flat surface of the large OD end of the frustum.
I imagine that a bigger loop antenna with its center on the axis of axi-symmetry of the cone would be ideal.
aero's model is very close to a sketch i post some times ago..Thats why i have sad "it looks like" at some pictures, the GIF files i build show TE012.Dr. Rodal,For some of the pics there seems to be a weak coupling of TE31 eigenvalue
New png files are uploaded for the 64 cycle Shell 2d loop antenna case. I put up the new csv files as well but they "should" be identical to the previous ones. The png files are named slightly differently than previously so I uploaded them into the existing folders. You won't have any difficulty telling the difference visually, but of course your computer will. I have attached one of the new files here just so all can see the effect of changing the scaling range. And note that the pixel grid separation is exactly the same, 1.1 mm while 1/20th of the length of the frustum is about 12 mm.
Still haven't made your x-30 slice that you asked for a few days ago. Will get it up soon.
https://drive.google.com/folderview?id=0B1XizxEfB23tfmVCZlhnNUVtTGRoTTlZSGJiT3ZfSHBvYnNELUc1WlN0Sk15ZDZud3pSWmM&usp=sharing (https://drive.google.com/folderview?id=0B1XizxEfB23tfmVCZlhnNUVtTGRoTTlZSGJiT3ZfSHBvYnNELUc1WlN0Sk15ZDZud3pSWmM&usp=sharing)
(I get ~2.39GHz for TE311 and ~2.63GHz for TE312, hope i didn't make a mistake! p=1 and p=2 are very close... Rechecked numbers are welcome).
Most interesting is that the whole run looks like coupling to different modes at different time steps inclusive target mode TE012 (TE31p,TM112?)
It is not a TE311 because TE311 has 6 poles equally spaced around the circumference and I don't see anything with 6 poles around the circumference.
Be careful with ascertaining what mode it is from the hstop images in the Meep file for this run because there are several fields that are mislabeled in these images.
Take a look instead at the raw output csv files which are fine.
Looking at the csv files it is clear that it is a TEm12 mode.
A circular cross-section should show a circular field for m=0, this is not the case because
a) cartesian coordinate fields are shown
b) the effect of the parallel 2-dipole antenna
I'm pretty sure that the mode shape is TE012 presenting a diameter indentation as an effect from the antenna.
So:
1) The good news is that aero finally succeeded in exciting a TE mode, by using a parallel 2-Dipole antenna
2) It is evident that the parallel 2-Dipole antenna severely affects the mode through the cross section, because the excitation is taking place practically like a line instead of a loop. What we learn from this is that to excite a perfect TE012 mode, a circular loop antenna is needed
Many books and articles talk about square and rectangular antennas. This is fine for rectangular cross-section cavities, but to excite a perfect mode in a circular cross-section cavity it appears that a circular loop-antenna is needed.
From Paul March, private communication.QuoteSteve: The current loop antenna in the copper frustum has a 14mm OD and is made from #20 AWG magnet wire soldered to an SMA bulkhead connector. This assembly is then rotated to maximize the S11 return loss for a given resonant frequency while using an RG-142 SMA-to-SMA coaxial cable run, which is typically 2.0 feet long. Location is on the frustum sidewall 1.35 inch up from the interior flat surface of the large OD end of the frustum.
Yes, I would expect much different cavity excitation if the antenna were on the central axis of rotation.
I also wonder about how much rotation was needed. Did the antenna end up in a horizontal or vertical plane relative to the big base, or was it some numbers of degrees away from either horizontal or vertical.
From Paul March, private communication.QuoteSteve: The current loop antenna in the copper frustum has a 14mm OD and is made from #20 AWG magnet wire soldered to an SMA bulkhead connector. This assembly is then rotated to maximize the S11 return loss for a given resonant frequency while using an RG-142 SMA-to-SMA coaxial cable run, which is typically 2.0 feet long. Location is on the frustum sidewall 1.35 inch up from the interior flat surface of the large OD end of the frustum.
Yes, I would expect much different cavity excitation if the antenna were on the central axis of rotation.
I also wonder about how much rotation was needed. Did the antenna end up in a horizontal or vertical plane relative to the big base, or was it some numbers of degrees away from either horizontal or vertical.
Rotation degree can be seen here
I saw that image, but that is a representation, not a photograph. No way to snap a photo from that angle inside the frustum or is there? I suppose they could have made the adjustments using the S11 return loss then removed the small end, stuck a camera inside and taken the shot.
https://en.wikipedia.org/wiki/Allais_effect
This is the (inconclusive) effect to which Hoagland referred in the radio show.
Allais’s explanation for another anomaly (the lunisolar periodicity in variations of the azimuth of a pendulum) is that space evinces certain anisotropic characteristics, which he ascribes to motion through an aether which is partially entrained by planetary bodies. He has presented this hypothesis in his 1997 book L’Anisotropie de l’espace. This explanation has not gained significant traction amongst mainstream scientists.
like to remenber:https://en.wikipedia.org/wiki/Allais_effect
This is the (inconclusive) effect to which Hoagland referred in the radio show.
This is interesting:QuoteAllais’s explanation for another anomaly (the lunisolar periodicity in variations of the azimuth of a pendulum) is that space evinces certain anisotropic characteristics, which he ascribes to motion through an aether which is partially entrained by planetary bodies. He has presented this hypothesis in his 1997 book L’Anisotropie de l’espace. This explanation has not gained significant traction amongst mainstream scientists.
don't know how helpful this is but i do search at arxiv.org for "tapered waveguide" ...
find this for exampe:
http://arxiv.org/pdf/1001.1254v1.pdf
and many many many more...
Only the whole community is able to review all of this ::)
Best tradeoff is obtained with the exponential formulation with a slow variation of the
material parameters
Doc, have a bit of news for you here. Because of the flexibility of the copper mesh, I can "compress" it with a band to form an exponential taper. Not a lot, but some.don't know how helpful this is but i do search at arxiv.org for "tapered waveguide" ...
find this for exampe:
http://arxiv.org/pdf/1001.1254v1.pdf
and many many many more...
Only the whole community is able to review all of this ::)
Thank you. I had not seen this paper.
This paper is very, very important as it answers a question that has repeatedly been asked in this forum and in Reddit:
what is the best function to use for the taper?
Shawyer used a linear taper (conical) but lacked the resources to explore other geometries (either numerically or by experiment)
Other researchers have not explored other taper geometries either
Musical people usually come with this question as to why don't people use musical horn shapes for the EM Drive. Invariably their question is answered by saying that the frequencies of the EM drive are much higher than the acoustical frequencies of French Horns, but the question of optimal shape is not answered.
The authors of this paper answer by saying:QuoteBest tradeoff is obtained with the exponential formulation with a slow variation of the
material parameters
that the best taper is exponential instead of linear (conical). However they do not use the same formulation of the problem as they don't of course deal with "thrust" (if there is such a thing) and they consider a simultaneous variation of material properties.
Doc, have a bit of news for you here. Because of the flexibility of the copper mesh, I can "compress" it with a band to form an exponential taper. Not a lot, but some.
Now, if I just knew how much and where ;)
...Sully positioned his more near the small end. So at full small-end extension, the waveguide will be roughly in the middle of the two end plates....From what we are learning from Meep, the best place to place the RF feed is near the big base, not at the middle and not at the small end. I initially thought it was better to have the antenna near the small end (based on several arguments). I have changed my mind based on the facts presented by multiple Meep runs.
...Sully positioned his more near the small end. So at full small-end extension, the waveguide will be roughly in the middle of the two end plates....From what we are learning from Meep, the best place to place the RF feed is near the big base, not at the middle and not at the small end. I initially thought it was better to have the antenna near the small end (based on several arguments). I have changed my mind based on the facts presented by multiple Meep runs.
Why? Do you believe it is better for resonance, or better for thrust? It seems counter intuitive because the big end will be reflecting more, not less.
Todd
Excellent analysis...Sully positioned his more near the small end. So at full small-end extension, the waveguide will be roughly in the middle of the two end plates....From what we are learning from Meep, the best place to place the RF feed is near the big base, not at the middle and not at the small end. I initially thought it was better to have the antenna near the small end (based on several arguments). I have changed my mind based on the facts presented by multiple Meep runs.
Why? Do you believe it is better for resonance, or better for thrust? It seems counter intuitive because the big end will be reflecting more, not less.
Todd
Assuming the antenna is 1/4 guide wavelength away from the end plate, the reflected EM wave is 180 deg out of phase with the radiating antenna. The big end plate becomes a reflector element in a 2 element array. This will cause more of the antenna's radiated energy to be directed at the small end than at the big end as the antenna is now directional.
http://www.ph.surrey.ac.uk/satellites/main/assets/schoolzone/project1/reflectors_directors.htm
Suspect this may also cause an out of phase shadow zone on the big end plate, reducing bounce Force inside the shadow zone due to phase distortion between the radiating antenna and the EM wave propagating from the small end..
Be careful with that, the eigenmodes in your frustum will get a shift to higher frequencies if you compress the side walls to a lower diameter.Doc, have a bit of news for you here. Because of the flexibility of the copper mesh, I can "compress" it with a band to form an exponential taper. Not a lot, but some.don't know how helpful this is but i do search at arxiv.org for "tapered waveguide" ...
find this for exampe:
http://arxiv.org/pdf/1001.1254v1.pdf
and many many many more...
Only the whole community is able to review all of this ::)
Thank you. I had not seen this paper.
This paper is very, very important as it answers a question that has repeatedly been asked in this forum and in Reddit:
what is the best function to use for the taper?
Shawyer used a linear taper (conical) but lacked the resources to explore other geometries (either numerically or by experiment)
Other researchers have not explored other taper geometries either
Musical people usually come with this question as to why don't people use musical horn shapes for the EM Drive. Invariably their question is answered by saying that the frequencies of the EM drive are much higher than the acoustical frequencies of French Horns, but the question of optimal shape is not answered.
The authors of this paper answer by saying:QuoteBest tradeoff is obtained with the exponential formulation with a slow variation of the
material parameters
that the best taper is exponential instead of linear (conical). However they do not use the same formulation of the problem as they don't of course deal with "thrust" (if there is such a thing) and they consider a simultaneous variation of material properties.
Now, if I just knew how much and where ;)
I keep thinking about the idea (http://forum.nasaspaceflight.com/index.php?topic=37642.msg1412971#msg1412971) I had a few days ago and pushed it further. I thought about Rodal and WarpTech's advice of increasing cone angle and keeping the apex as near as possible of the small end. I also kept Shawyer's high Df and concentric spherical ends to maintain a high Q, and I've ended up with this wide and shallow resonant design, with incredible large spherical ends, making the frustum almost a half-sphere:
Db = 600 mm
Ds = 150 mm
L = 51.20 mm
r1 = 76.92 mm
r2 = 307.67 mm
r2-r1 = 230.75 mm
θ = 77.18°
Resonance at 2.45 GHz in TE013 mode, Df = 0.96
Would be a challenge to build but nevertheless interesting to test. What could be the Q of such a cavity?
I might be able to model it. Can you export an STL of the part?
Although SketchUp is not good at all with circles (it draws them as a series of segments) I updated the number of segments per circle from 24 to 240 in order to improve precision.
I don't know if you need the 2D plan or the 3D modeled object, so I created both versions and exported them in STL format. You can find them zipped below.
This is a very interesting shape to test the outer limits of the theories and methods involved.
Due to the extreme spherical conical shape of this cavity, the limitations of the spreadsheet approach (that in a kludgy way intends to model a spherical cone as a large series of cylindrical waveguides) is more crudely exposed:
the natural frequency of mode TE013 is 2.132 GHz (instead of 2.45 GHz), a difference of 15% in frequency (for cone angles of 15 degrees the spreadsheet is 1 to 2% different from the exact solution)
It does resonate, and it resonates well:
theoretical Q = 94,254
using a resistivity = 1.678*10^(-8)(*copper*) (Q will go down with increasing resitivity materials and geometrical imperfections)
although this is not much more than the Q calculated for the 30 degrees cavity, so it looks like there are diminishing returns after 30 degrees
I attach below the contour plots for
1) the magnetic field in the spherical radial direction
2) the electric field in the azimuthal circumferential direction
Note how distorted is the magnetic field in the spherical radial direction
...Um doc, didn't the South African science fair experiment show greater thrust by increasing the size of the cavity? Seems like that would indicate that volume of the cavity and not just Q is a factor.1) Volume of the cavity was taken into account in the calculations: one cannot calculate the natural frequency and mode shape without knowing the dimensions. To calculate the quality factor Q one needs to perform an integration of the electromagnetic fields over the whole volume. Thus the Q is very much related to the volume.
don't know how helpful this is but i do search at arxiv.org for "tapered waveguide" ...
find this for exampe:
http://arxiv.org/pdf/1001.1254v1.pdf
and many many many more...
Only the whole community is able to review all of this ::)
Thank you. I had not seen this paper.
This paper is very, very important as it answers a question that has repeatedly been asked in this forum and in Reddit:
what is the best function to use for the taper?
Shawyer used a linear taper (conical) but lacked the resources to explore other geometries (either numerically or by experiment)
Other researchers have not explored other taper geometries either
Musical people usually come with this question as to why don't people use musical horn shapes for the EM Drive. Invariably their question is answered by saying that the frequencies of the EM drive are much higher than the acoustical frequencies of French Horns, but the question of optimal shape is not answered.
The authors of this paper answer by saying:QuoteBest tradeoff is obtained with the exponential formulation with a slow variation of the
material parameters
that the best taper is exponential instead of linear (conical). However they do not use the same formulation of the problem as they don't of course deal with "thrust" (if there is such a thing) and they consider a simultaneous variation of material properties.
Here are the force calculations corresponding to the stresses shown in http://forum.nasaspaceflight.com/index.php?topic=38203.msg1416281#msg1416281
Some noteworthy comments:
1) The force magnitude is a whooping 10,000 times higher than for previous cases. At this point we don't know how much of this greater magnitude is due to the fact that this computer run is for twice as long a time as previous runs (with stresses that are increasing with time) and how much is due to the fact that this force is due to a transverse electric (TE) mode shape while the other ones were for transverse magnetic (TM) modes.
2) Due to the fact that the stress is tensile at the small base and compressive at the big base, both forces, at the small base and at the big base point in the same direction, from the small base towards the big base. This is the first run where we encounter both forces pointing in the same direction. This is only possible for TE modes because they have a magnetic axial field and the magnetic field is able to impart either a tensile or a compressive force on a surface (while the TM modes have electric axial fields that can only impart a compressive force on surfaces). From the geometry, the force on the lateral conical surfaces due to the electric field must be in the opposite direction, from the big base towards the small base, countering the net force on the bases.
3) This computer run had the antenna positioned near the small end. It will be very interesting to see whether having the antenna at the big end results in a net force in the opposite direction (as previously observed in previous runs with the antenna near the big end for TM modes) which cannot be countered by the lateral conical surfaces.
Hi Shell.Here are the force calculations corresponding to the stresses shown in http://forum.nasaspaceflight.com/index.php?topic=38203.msg1416281#msg1416281
Some noteworthy comments:
1) The force magnitude is a whooping 10,000 times higher than for previous cases. At this point we don't know how much of this greater magnitude is due to the fact that this computer run is for twice as long a time as previous runs (with stresses that are increasing with time) and how much is due to the fact that this force is due to a transverse electric (TE) mode shape while the other ones were for transverse magnetic (TM) modes.
2) Due to the fact that the stress is tensile at the small base and compressive at the big base, both forces, at the small base and at the big base point in the same direction, from the small base towards the big base. This is the first run where we encounter both forces pointing in the same direction. This is only possible for TE modes because they have a magnetic axial field and the magnetic field is able to impart either a tensile or a compressive force on a surface (while the TM modes have electric axial fields that can only impart a compressive force on surfaces). From the geometry, the force on the lateral conical surfaces due to the electric field must be in the opposite direction, from the big base towards the small base, countering the net force on the bases.
3) This computer run had the antenna positioned near the small end. It will be very interesting to see whether having the antenna at the big end results in a net force in the opposite direction (as previously observed in previous runs with the antenna near the big end for TM modes) which cannot be countered by the lateral conical surfaces.
A very nice piece of work Dr. Rodal! I was expecting an increase in stress forces for the TE mode although not nearly this magnitude. And what is interesting the antenna is out of phase creating a shadow zone in the small cavity of decaying waveforms. Interesting.
I'm waiting for the big end run to finalize the second generation placement of the dual waveguide insertion into the cavity from a single magnetron source.
I fussed over how to make the small plate adjustable with a "Rube Goldberg" contraption on the outside of the frustum to the bottom secured plat to allow for thermal expansion of the walls and hated each iteration. I flashed on an idea of using a quartz rod which is very transparent to microwaves down through the very center, attaching the large base to it and the letting the top small base slide inside of the extended cavity. Still need to capture the small plate with a hollow threaded rod on the outside of it and a captured nut extended to the sidewalls of the extended cavity. This is where I stopped and still fleshing the little details out. The waveguides are just for looks and not representative of where the final fleshed out design will be.
Busy day today, off to lurking in the shop.
Shell
Hi Shell.Here are the force calculations corresponding to the stresses shown in http://forum.nasaspaceflight.com/index.php?topic=38203.msg1416281#msg1416281
Some noteworthy comments:
1) The force magnitude is a whooping 10,000 times higher than for previous cases. At this point we don't know how much of this greater magnitude is due to the fact that this computer run is for twice as long a time as previous runs (with stresses that are increasing with time) and how much is due to the fact that this force is due to a transverse electric (TE) mode shape while the other ones were for transverse magnetic (TM) modes.
2) Due to the fact that the stress is tensile at the small base and compressive at the big base, both forces, at the small base and at the big base point in the same direction, from the small base towards the big base. This is the first run where we encounter both forces pointing in the same direction. This is only possible for TE modes because they have a magnetic axial field and the magnetic field is able to impart either a tensile or a compressive force on a surface (while the TM modes have electric axial fields that can only impart a compressive force on surfaces). From the geometry, the force on the lateral conical surfaces due to the electric field must be in the opposite direction, from the big base towards the small base, countering the net force on the bases.
3) This computer run had the antenna positioned near the small end. It will be very interesting to see whether having the antenna at the big end results in a net force in the opposite direction (as previously observed in previous runs with the antenna near the big end for TM modes) which cannot be countered by the lateral conical surfaces.
A very nice piece of work Dr. Rodal! I was expecting an increase in stress forces for the TE mode although not nearly this magnitude. And what is interesting the antenna is out of phase creating a shadow zone in the small cavity of decaying waveforms. Interesting.
I'm waiting for the big end run to finalize the second generation placement of the dual waveguide insertion into the cavity from a single magnetron source.
I fussed over how to make the small plate adjustable with a "Rube Goldberg" contraption on the outside of the frustum to the bottom secured plat to allow for thermal expansion of the walls and hated each iteration. I flashed on an idea of using a quartz rod which is very transparent to microwaves down through the very center, attaching the large base to it and the letting the top small base slide inside of the extended cavity. Still need to capture the small plate with a hollow threaded rod on the outside of it and a captured nut extended to the sidewalls of the extended cavity. This is where I stopped and still fleshing the little details out. The waveguides are just for looks and not representative of where the final fleshed out design will be.
Busy day today, off to lurking in the shop.
Shell
At the first look the orientation of your rectangular waveguide is not the best to excite TE012 (for the other possible modes i have to think about later this day...).
For this type of waveguide the E field is in b-direction which is the shorter side of the rectangle.. H is in a-z direction(z means propagation direction in the waveguide). For TE01 i would rotate both antennas 90deg. But of course its your turn. :)
Picture source:wikipedia
It is a hexagon. She made the sides flat to make it easier to attach 2 magnetrons opposite each other, so they will couple and synchronize.
Now you're saying she should mount them to the opposing 120-deg corners? If what you say is correct, then a rectangle or octagon would've been better than a hexagon.
Todd
True...Hi Shell.Here are the force calculations corresponding to the stresses shown in http://forum.nasaspaceflight.com/index.php?topic=38203.msg1416281#msg1416281
Some noteworthy comments:
1) The force magnitude is a whooping 10,000 times higher than for previous cases. At this point we don't know how much of this greater magnitude is due to the fact that this computer run is for twice as long a time as previous runs (with stresses that are increasing with time) and how much is due to the fact that this force is due to a transverse electric (TE) mode shape while the other ones were for transverse magnetic (TM) modes.
2) Due to the fact that the stress is tensile at the small base and compressive at the big base, both forces, at the small base and at the big base point in the same direction, from the small base towards the big base. This is the first run where we encounter both forces pointing in the same direction. This is only possible for TE modes because they have a magnetic axial field and the magnetic field is able to impart either a tensile or a compressive force on a surface (while the TM modes have electric axial fields that can only impart a compressive force on surfaces). From the geometry, the force on the lateral conical surfaces due to the electric field must be in the opposite direction, from the big base towards the small base, countering the net force on the bases.
3) This computer run had the antenna positioned near the small end. It will be very interesting to see whether having the antenna at the big end results in a net force in the opposite direction (as previously observed in previous runs with the antenna near the big end for TM modes) which cannot be countered by the lateral conical surfaces.
A very nice piece of work Dr. Rodal! I was expecting an increase in stress forces for the TE mode although not nearly this magnitude. And what is interesting the antenna is out of phase creating a shadow zone in the small cavity of decaying waveforms. Interesting.
I'm waiting for the big end run to finalize the second generation placement of the dual waveguide insertion into the cavity from a single magnetron source.
I fussed over how to make the small plate adjustable with a "Rube Goldberg" contraption on the outside of the frustum to the bottom secured plat to allow for thermal expansion of the walls and hated each iteration. I flashed on an idea of using a quartz rod which is very transparent to microwaves down through the very center, attaching the large base to it and the letting the top small base slide inside of the extended cavity. Still need to capture the small plate with a hollow threaded rod on the outside of it and a captured nut extended to the sidewalls of the extended cavity. This is where I stopped and still fleshing the little details out. The waveguides are just for looks and not representative of where the final fleshed out design will be.
Busy day today, off to lurking in the shop.
Shell
At the first look the orientation of your rectangular waveguide is not the best to excite TE012 (for the other possible modes i have to think about later this day...).
For this type of waveguide the E field is in b-direction which is the shorter side of the rectangle.. H is in a-z direction(z means propagation direction in the waveguide). For TE01 i would rotate both antennas 90deg. But of course its your turn. :)
What?Hi Shell.Here are the force calculations corresponding to the stresses shown in http://forum.nasaspaceflight.com/index.php?topic=38203.msg1416281#msg1416281
Some noteworthy comments:
1) The force magnitude is a whooping 10,000 times higher than for previous cases. At this point we don't know how much of this greater magnitude is due to the fact that this computer run is for twice as long a time as previous runs (with stresses that are increasing with time) and how much is due to the fact that this force is due to a transverse electric (TE) mode shape while the other ones were for transverse magnetic (TM) modes.
2) Due to the fact that the stress is tensile at the small base and compressive at the big base, both forces, at the small base and at the big base point in the same direction, from the small base towards the big base. This is the first run where we encounter both forces pointing in the same direction. This is only possible for TE modes because they have a magnetic axial field and the magnetic field is able to impart either a tensile or a compressive force on a surface (while the TM modes have electric axial fields that can only impart a compressive force on surfaces). From the geometry, the force on the lateral conical surfaces due to the electric field must be in the opposite direction, from the big base towards the small base, countering the net force on the bases.
3) This computer run had the antenna positioned near the small end. It will be very interesting to see whether having the antenna at the big end results in a net force in the opposite direction (as previously observed in previous runs with the antenna near the big end for TM modes) which cannot be countered by the lateral conical surfaces.
A very nice piece of work Dr. Rodal! I was expecting an increase in stress forces for the TE mode although not nearly this magnitude. And what is interesting the antenna is out of phase creating a shadow zone in the small cavity of decaying waveforms. Interesting.
I'm waiting for the big end run to finalize the second generation placement of the dual waveguide insertion into the cavity from a single magnetron source.
I fussed over how to make the small plate adjustable with a "Rube Goldberg" contraption on the outside of the frustum to the bottom secured plat to allow for thermal expansion of the walls and hated each iteration. I flashed on an idea of using a quartz rod which is very transparent to microwaves down through the very center, attaching the large base to it and the letting the top small base slide inside of the extended cavity. Still need to capture the small plate with a hollow threaded rod on the outside of it and a captured nut extended to the sidewalls of the extended cavity. This is where I stopped and still fleshing the little details out. The waveguides are just for looks and not representative of where the final fleshed out design will be.
Busy day today, off to lurking in the shop.
Shell
At the first look the orientation of your rectangular waveguide is not the best to excite TE012 (for the other possible modes i have to think about later this day...).
For this type of waveguide the E field is in b-direction which is the shorter side of the rectangle.. H is in a-z direction(z means propagation direction in the waveguide). For TE01 i would rotate both antennas 90deg. But of course its your turn. :)
Picture source:wikipedia
It is a hexagon. She made the sides flat to make it easier to attach 2 magnetrons opposite each other, so they will couple and synchronize. Now you're saying she should mount them to the opposing 120-deg corners? If what you say is correct, then a rectangle or octagon would've been better than a hexagon.
Todd
Why not? Its simple to use and you have a VNA, you could use the guides for tuning (impedance) Its simple to use some screws...True...Hi Shell.Here are the force calculations corresponding to the stresses shown in http://forum.nasaspaceflight.com/index.php?topic=38203.msg1416281#msg1416281
Some noteworthy comments:
1) The force magnitude is a whooping 10,000 times higher than for previous cases. At this point we don't know how much of this greater magnitude is due to the fact that this computer run is for twice as long a time as previous runs (with stresses that are increasing with time) and how much is due to the fact that this force is due to a transverse electric (TE) mode shape while the other ones were for transverse magnetic (TM) modes.
2) Due to the fact that the stress is tensile at the small base and compressive at the big base, both forces, at the small base and at the big base point in the same direction, from the small base towards the big base. This is the first run where we encounter both forces pointing in the same direction. This is only possible for TE modes because they have a magnetic axial field and the magnetic field is able to impart either a tensile or a compressive force on a surface (while the TM modes have electric axial fields that can only impart a compressive force on surfaces). From the geometry, the force on the lateral conical surfaces due to the electric field must be in the opposite direction, from the big base towards the small base, countering the net force on the bases.
3) This computer run had the antenna positioned near the small end. It will be very interesting to see whether having the antenna at the big end results in a net force in the opposite direction (as previously observed in previous runs with the antenna near the big end for TM modes) which cannot be countered by the lateral conical surfaces.
A very nice piece of work Dr. Rodal! I was expecting an increase in stress forces for the TE mode although not nearly this magnitude. And what is interesting the antenna is out of phase creating a shadow zone in the small cavity of decaying waveforms. Interesting.
I'm waiting for the big end run to finalize the second generation placement of the dual waveguide insertion into the cavity from a single magnetron source.
I fussed over how to make the small plate adjustable with a "Rube Goldberg" contraption on the outside of the frustum to the bottom secured plat to allow for thermal expansion of the walls and hated each iteration. I flashed on an idea of using a quartz rod which is very transparent to microwaves down through the very center, attaching the large base to it and the letting the top small base slide inside of the extended cavity. Still need to capture the small plate with a hollow threaded rod on the outside of it and a captured nut extended to the sidewalls of the extended cavity. This is where I stopped and still fleshing the little details out. The waveguides are just for looks and not representative of where the final fleshed out design will be.
Busy day today, off to lurking in the shop.
Shell
At the first look the orientation of your rectangular waveguide is not the best to excite TE012 (for the other possible modes i have to think about later this day...).
For this type of waveguide the E field is in b-direction which is the shorter side of the rectangle.. H is in a-z direction(z means propagation direction in the waveguide). For TE01 i would rotate both antennas 90deg. But of course its your turn. :)
I just popped them in not worrying about correct orientation, just for looks. They will be rotated, just hadn't gotten to it. I also have a quote coming on waveguides and chances are I'll not be using these guides.
...Yes, I think that the best location for the antenna is near the Big End (http://forum.nasaspaceflight.com/index.php?topic=38203.msg1416350#msg1416350), and not near the Small End as in this run.
A very nice piece of work Dr. Rodal! I was expecting an increase in stress forces for the TE mode although not nearly this magnitude. And what is interesting the antenna is out of phase creating a shadow zone in the small cavity of decaying waveforms. Interesting.
I'm waiting for the big end run to finalize the second generation placement of the dual waveguide insertion into the cavity from a single magnetron source.
I fussed over how to make the small plate adjustable with a "Rube Goldberg" contraption on the outside of the frustum to the bottom secured plat to allow for thermal expansion of the walls and hated each iteration. I flashed on an idea of using a quartz rod which is very transparent to microwaves down through the very center, attaching the large base to it and the letting the top small base slide inside of the extended cavity. Still need to capture the small plate with a hollow threaded rod on the outside of it and a captured nut extended to the sidewalls of the extended cavity. This is where I stopped and still fleshing the little details out. The waveguides are just for looks and not representative of where the final fleshed out design will be.
Busy day today, off to lurking in the shop.
Shell
Out of state guests for the next few days. Looking like fulcrum test will be Tuesday, August 25th on NSF-1701....Yes, I think that the best location for the antenna is near the Big End (http://forum.nasaspaceflight.com/index.php?topic=38203.msg1416350#msg1416350), and not near the Small End as in this run.
A very nice piece of work Dr. Rodal! I was expecting an increase in stress forces for the TE mode although not nearly this magnitude. And what is interesting the antenna is out of phase creating a shadow zone in the small cavity of decaying waveforms. Interesting.
I'm waiting for the big end run to finalize the second generation placement of the dual waveguide insertion into the cavity from a single magnetron source.
I fussed over how to make the small plate adjustable with a "Rube Goldberg" contraption on the outside of the frustum to the bottom secured plat to allow for thermal expansion of the walls and hated each iteration. I flashed on an idea of using a quartz rod which is very transparent to microwaves down through the very center, attaching the large base to it and the letting the top small base slide inside of the extended cavity. Still need to capture the small plate with a hollow threaded rod on the outside of it and a captured nut extended to the sidewalls of the extended cavity. This is where I stopped and still fleshing the little details out. The waveguides are just for looks and not representative of where the final fleshed out design will be.
Busy day today, off to lurking in the shop.
Shell
Looking forward to that 64 cycle Meep run with the antenna at the Big End to compare and most of all I look forward to the NSF-1701 and Yang/Shell tests.
"Like a trombone" I said...
Todd
Yes, just in to take a sliver out. But like this.It is a hexagon. She made the sides flat to make it easier to attach 2 magnetrons opposite each other, so they will couple and synchronize.
For now SeeShells will use one single magnetron that has 2 outputs, so the waves come in a more symmetric fashion inside.Now you're saying she should mount them to the opposing 120-deg corners? If what you say is correct, then a rectangle or octagon would've been better than a hexagon.
Todd
I think X_RaY proposed to turn the waveguides 90° but they are kept at the same place on the cavity wall, so the longer side of the waveguides becomes vertical and the short length of the waveguides is positioned along the horizontal plane.
"Like a trombone" I said...
Todd
I'm thinking Baritone at this point... A baritone might be big enough to allow the use of a 2.45GHz magnetron.
Here's a shiny one for 150 bucks
http://www.alibaba.com/product-detail/Baritone_210767159.html?spm=a2700.7724838.35.1.BBzfaa
"Like a trombone" I said...
Todd
I'm thinking Baritone at this point... A baritone might be big enough to allow the use of a 2.45GHz magnetron.
Here's a shiny one for 150 bucks
http://www.alibaba.com/product-detail/Baritone_210767159.html?spm=a2700.7724838.35.1.BBzfaa
A 9" Trombone works too, but I came to the same conclusion. A Baritone would work, they're just pricey.
Todd
"Like a trombone" I said...
Todd
I'm thinking Baritone at this point... A baritone might be big enough to allow the use of a 2.45GHz magnetron.
Here's a shiny one for 150 bucks
http://www.alibaba.com/product-detail/Baritone_210767159.html?spm=a2700.7724838.35.1.BBzfaa
A 9" Trombone works too, but I came to the same conclusion. A Baritone would work, they're just pricey.
Todd
I love the idea of using brass instruments for the frustrum.
I just wonder how brass will work as the material of the frustrum? vs copper or copper mesh?
Standing wave visualisation.It cannot be overemphasized how important it is to determine what mode shape is being excited in experiments and this looks like an alternative way to do it.
What do you think guys. a suggestion?
This appears to be dirty and simple way to compare simulations to actual test data.
Inside those resonant cavities for DIY's?
so for $2.00 a roll or buying some thermal A4 fax paper it chould be a cheap test.
...
Resistivity ohm-m
Pure Copper 1.664 E-08
High Strength Yellow Brass 1.437 E-07
Ratio of resistivities 8.64
Square Root of Ratio 2.94
So using High Strength Yellow Brass implies a quality of resonance Q about 1/3 that of using pure copper
http://eddy-current.com/conductivity-of-metals-sorted-by-resistivity/
Resistivity ohm-m
Pure Copper 1.664 E-08
High Strength Yellow Brass 1.437 E-07
Ratio of resistivities 8.64
Square Root of Ratio 2.94
So using High Strength Yellow Brass implies a quality of resonance Q about 1/3 that of using pure copper
QuoteResistivity ohm-m
Pure Copper 1.664 E-08
High Strength Yellow Brass 1.437 E-07
Ratio of resistivities 8.64
Square Root of Ratio 2.94
So using High Strength Yellow Brass implies a quality of resonance Q about 1/3 that of using pure copper
Hmmm...
1 - Possibly a used or damaged instrument would work, seeing as we'd be concerned only with the one end?
2 - Perhaps it would be possible to silver coat the interior?
1) The force magnitude is a whooping 10,000 times higher than for previous cases. At this point we don't know how much of this greater magnitude is due to the fact that this computer run is for twice as long a time as previous runs (with stresses that are increasing with time) and how much is due to the fact that this force is due to a transverse electric (TE) mode shape while the other ones were for transverse magnetic (TM) modes.
1) The force magnitude is a whooping 10,000 times higher than for previous cases.
QuoteResistivity ohm-m
Pure Copper 1.664 E-08
High Strength Yellow Brass 1.437 E-07
Ratio of resistivities 8.64
Square Root of Ratio 2.94
So using High Strength Yellow Brass implies a quality of resonance Q about 1/3 that of using pure copper
Hmmm...
1 - Possibly a used or damaged instrument would work, seeing as we'd be concerned only with the one end?
2 - Perhaps it would be possible to silver coat the interior?
Brass can easily be electroplated with pure copper, or gold plated. The shape and consistency is what I like about it.
Todd
The only experimenters so far that have actually measured and reported a mode shape has been NASA Eagleworks that actually measured TM212 mode shape by using a thermal camera pointed at the big base.
1) The force magnitude is a whooping 10,000 times higher than for previous cases. At this point we don't know how much of this greater magnitude is due to the fact that this computer run is for twice as long a time as previous runs (with stresses that are increasing with time) and how much is due to the fact that this force is due to a transverse electric (TE) mode shape while the other ones were for transverse magnetic (TM) modes.
Just to clarify, you mean an increase of 10^4 not 10^10000.
10,000 times highercannot mean 10^10,000 under any interpretation I am aware of.
This seems highly relevant.
http://iopscience.iop.org/1367-2630/17/5/053035/pdf/1367-2630_17_5_053035.pdf
Experimental evidence for Abraham pressure of light
Keywords: momentum of light, light in media, optomechanics, optofluidics
Abstract
The question of how much momentum light carries in media has been debated for over a century.
Two rivalling theories, one from 1908 by Hermann Minkowski and the other from 1909 by Max
Abraham, predict the exact opposite when light enters an optical material: a pulling force in
Minkowskiʼs case and a pushing force in Abrahamʼs. Most experimental tests have agreed with
Minkowskiʼs theory, but here we report the first quantitative experimental evidence for Abrahamʼs
pushing pressure of light. Our results matter in optofluidics and optomechanics, and wherever light
exerts mechanical pressure.
"Like a trombone" I said...
Todd
I'm thinking Baritone at this point... A baritone might be big enough to allow the use of a 2.45GHz magnetron.
Here's a shiny one for 150 bucks
http://www.alibaba.com/product-detail/Baritone_210767159.html?spm=a2700.7724838.35.1.BBzfaa
That is exactly what it looks like Dr. Rodal and yes you would have a rotational mish- mashed asymmetry of the modes with one loop.2) It is evident that the parallel 2-Dipole antenna severely affects the mode. What we learn from this is that to excite a perfect TE012 mode, a circular loop antenna is needed
Many books and articles talk about square and rectangular antennas. This is fine for rectangular cross-section cavities, but to excite a perfect mode in a circular cross-section cavity it appears that a circular loop-antenna is needed.
Like this?
NASA must have the RF near the big end (correct me if I'm wrong) because they have the dielectric at the small end blocking the ability to put an antenna there.
It appears (correct me if I'm wrong) that NASA has the circular loop near the conical lateral surface. From the Meep runs I have learned that this produces all kinds of asymmetric waves that decrease the Q. It would be much better to have the circular loop in the very center with the axis of axi-symmetry of the cone going through the center of the circular loop antenna instead of being offset.
I imagine that a bigger loop antenna with its center on the axis of axi-symmetry of the cone would be ideal.
I wonder whether this placement of the NASA loop feed being so asymmetric is one of the reasons that NASA was not able to robustly reproduce TE modes (the only successful TE test they were able to conduct with only 2 watts input power was the mode that produced the most force/InputPower NASA ever reported). NASA has been running TM212 ever since.
...That is exactly what it looks like Dr. Rodal and yes you would have a rotational mish- mashed asymmetry of the modes with one loop.Shell,
Instead of the center placement, let's force the TE012 modes by placing 4 loops around the base circumference thereby pushing the modes to develop inline with the loops. 2 in phase and 2 out of phase by 180 degrees. This should almost act like an active filter locking out any other modes except for the small end where they might try to develop and then be pushed into the small end.
If we still wanted to maintain TE012 and have a rotational mixer (for you rfmwguy) angle the loops 11.25 degrees (multiples of 360 measured it in the pic) close like the loop in the EW photo.
Morning coffee thoughts,
Shell
...That is exactly what it looks like Dr. Rodal and yes you would have a rotational mish- mashed asymmetry of the modes with one loop.Shell,
Instead of the center placement, let's force the TE012 modes by placing 4 loops around the base circumference thereby pushing the modes to develop inline with the loops. 2 in phase and 2 out of phase by 180 degrees. This should almost act like an active filter locking out any other modes except for the small end where they might try to develop and then be pushed into the small end.
If we still wanted to maintain TE012 and have a rotational mixer (for you rfmwguy) angle the loops 11.25 degrees (multiples of 360 measured it in the pic) close like the loop in the EW photo.
Morning coffee thoughts,
Shell
I noticed that the image "ezz30-t04.png" attached in your message corresponds to the latest set calculated by Meep, inside the cavity, at longitudinal location "30".
I don't know at what time (from RF being turned ON) are these images calculated, do you know whether they correspond to a Meep total run time of 640 time slices = "64 periods" = 0.026 microseconds or whether they correspond to 320 time slices ="32 periods" = 0.013 microseconds ?
At 180 deg phase shift all the antennas would work against the next antenna nearby.That is exactly what it looks like Dr. Rodal and yes you would have a rotational mish- mashed asymmetry of the modes with one loop.2) It is evident that the parallel 2-Dipole antenna severely affects the mode. What we learn from this is that to excite a perfect TE012 mode, a circular loop antenna is needed
Many books and articles talk about square and rectangular antennas. This is fine for rectangular cross-section cavities, but to excite a perfect mode in a circular cross-section cavity it appears that a circular loop-antenna is needed.
Like this?
NASA must have the RF near the big end (correct me if I'm wrong) because they have the dielectric at the small end blocking the ability to put an antenna there.
It appears (correct me if I'm wrong) that NASA has the circular loop near the conical lateral surface. From the Meep runs I have learned that this produces all kinds of asymmetric waves that decrease the Q. It would be much better to have the circular loop in the very center with the axis of axi-symmetry of the cone going through the center of the circular loop antenna instead of being offset.
I imagine that a bigger loop antenna with its center on the axis of axi-symmetry of the cone would be ideal.
I wonder whether this placement of the NASA loop feed being so asymmetric is one of the reasons that NASA was not able to robustly reproduce TE modes (the only successful TE test they were able to conduct with only 2 watts input power was the mode that produced the most force/InputPower NASA ever reported). NASA has been running TM212 ever since.
Instead of the center placement, let's force the TE012 modes by placing 4 loops around the base circumference thereby pushing the modes to develop inline with the loops. 2 in phase and 2 out of phase by 180 degrees. This should almost act like an active filter locking out any other modes except for the small end where they might try to develop and then be pushed into the small end.
If we still wanted to maintain TE012 and have a rotational mixer (for you rfmwguy) angle the loops 11.25 degrees (multiples of 360 measured it in the pic) close like the loop in the EW photo.
Morning coffee thoughts,
Shell
64 cycle Shell 2D loop ant › z-30-pngs...That is exactly what it looks like Dr. Rodal and yes you would have a rotational mish- mashed asymmetry of the modes with one loop.Shell,
Instead of the center placement, let's force the TE012 modes by placing 4 loops around the base circumference thereby pushing the modes to develop inline with the loops. 2 in phase and 2 out of phase by 180 degrees. This should almost act like an active filter locking out any other modes except for the small end where they might try to develop and then be pushed into the small end.
If we still wanted to maintain TE012 and have a rotational mixer (for you rfmwguy) angle the loops 11.25 degrees (multiples of 360 measured it in the pic) close like the loop in the EW photo.
Morning coffee thoughts,
Shell
I noticed that the image "ezz30-t04.png" attached in your message corresponds to the latest set calculated by Meep, inside the cavity, at longitudinal location "30".
I don't know at what time (from RF being turned ON) are these images calculated, do you know whether they correspond to a Meep total run time of 640 time slices = "64 periods" = 0.026 microseconds or whether they correspond to 320 time slices ="32 periods" = 0.013 microseconds ?
I believe they are the same but the CSV run is little different with the last set cleaned up in the post filtering showing a little better mode action, if I have the info correct. It is a little hard to keep it all straight....So what is then the difference between the contents of this folder
That's for the 64 cycle run. It matches the image, "ezz30-t04.png" and anyway, the 64 cycle run is the only one for which I have generated the z-30 slice data so far.
new-csvs
with the contents of this folder
64-cycle-run ...
Both of them are in the 64 cycle Shell 2D loop ant folder
You think about and post your ideas for discussion. I like that :)I believe they are the same but the CSV run is little different with the last set cleaned up in the post filtering showing a little better mode action, if I have the info correct. It is a little hard to keep it all straight....So what is then the difference between the contents of this folder
That's for the 64 cycle run. It matches the image, "ezz30-t04.png" and anyway, the 64 cycle run is the only one for which I have generated the z-30 slice data so far.
new-csvs
with the contents of this folder
64-cycle-run ...
Both of them are in the 64 cycle Shell 2D loop ant folder
The pic was for just to show a mode to explain the idea I was trying to get across and not anything else.
Shell
Ok i see what you're trying to say and that would work.At 180 deg phase shift all the antennas would work against the next antenna nearby.That is exactly what it looks like Dr. Rodal and yes you would have a rotational mish- mashed asymmetry of the modes with one loop.2) It is evident that the parallel 2-Dipole antenna severely affects the mode. What we learn from this is that to excite a perfect TE012 mode, a circular loop antenna is needed
Many books and articles talk about square and rectangular antennas. This is fine for rectangular cross-section cavities, but to excite a perfect mode in a circular cross-section cavity it appears that a circular loop-antenna is needed.
Like this?
NASA must have the RF near the big end (correct me if I'm wrong) because they have the dielectric at the small end blocking the ability to put an antenna there.
It appears (correct me if I'm wrong) that NASA has the circular loop near the conical lateral surface. From the Meep runs I have learned that this produces all kinds of asymmetric waves that decrease the Q. It would be much better to have the circular loop in the very center with the axis of axi-symmetry of the cone going through the center of the circular loop antenna instead of being offset.
I imagine that a bigger loop antenna with its center on the axis of axi-symmetry of the cone would be ideal.
I wonder whether this placement of the NASA loop feed being so asymmetric is one of the reasons that NASA was not able to robustly reproduce TE modes (the only successful TE test they were able to conduct with only 2 watts input power was the mode that produced the most force/InputPower NASA ever reported). NASA has been running TM212 ever since.
Instead of the center placement, let's force the TE012 modes by placing 4 loops around the base circumference thereby pushing the modes to develop inline with the loops. 2 in phase and 2 out of phase by 180 degrees. This should almost act like an active filter locking out any other modes except for the small end where they might try to develop and then be pushed into the small end.
If we still wanted to maintain TE012 and have a rotational mixer (for you rfmwguy) angle the loops 11.25 degrees (multiples of 360 measured it in the pic) close like the loop in the EW photo.
Morning coffee thoughts,
Shell
2 of them produce a magnetic field in one direction the other 2 in the opposite. That is against the field directions/vectors of the TE01p mode.
All of them in phase will work as well
EDIT:
Its the same like the 2 antennas "look" in the opposite direction (magnetic North Pole/South Pole of the loop).
It would work for TE012 if 2 antennas are near the small end and 2 (180°Phase shifted)antennas are near the big end if they have the same orientation.
At the end the pics from simulations have to look like at the picture.Ok i see what you're trying to say and that would work.At 180 deg phase shift all the antennas would work against the next antenna nearby.That is exactly what it looks like Dr. Rodal and yes you would have a rotational mish- mashed asymmetry of the modes with one loop.2) It is evident that the parallel 2-Dipole antenna severely affects the mode. What we learn from this is that to excite a perfect TE012 mode, a circular loop antenna is needed
Many books and articles talk about square and rectangular antennas. This is fine for rectangular cross-section cavities, but to excite a perfect mode in a circular cross-section cavity it appears that a circular loop-antenna is needed.
Like this?
NASA must have the RF near the big end (correct me if I'm wrong) because they have the dielectric at the small end blocking the ability to put an antenna there.
It appears (correct me if I'm wrong) that NASA has the circular loop near the conical lateral surface. From the Meep runs I have learned that this produces all kinds of asymmetric waves that decrease the Q. It would be much better to have the circular loop in the very center with the axis of axi-symmetry of the cone going through the center of the circular loop antenna instead of being offset.
I imagine that a bigger loop antenna with its center on the axis of axi-symmetry of the cone would be ideal.
I wonder whether this placement of the NASA loop feed being so asymmetric is one of the reasons that NASA was not able to robustly reproduce TE modes (the only successful TE test they were able to conduct with only 2 watts input power was the mode that produced the most force/InputPower NASA ever reported). NASA has been running TM212 ever since.
Instead of the center placement, let's force the TE012 modes by placing 4 loops around the base circumference thereby pushing the modes to develop inline with the loops. 2 in phase and 2 out of phase by 180 degrees. This should almost act like an active filter locking out any other modes except for the small end where they might try to develop and then be pushed into the small end.
If we still wanted to maintain TE012 and have a rotational mixer (for you rfmwguy) angle the loops 11.25 degrees (multiples of 360 measured it in the pic) close like the loop in the EW photo.
Morning coffee thoughts,
Shell
2 of them produce a magnetic field in one direction the other 2 in the opposite. That is against the field directions/vectors of the TE01p mode.
All of them in phase will work as well
EDIT:
Its the same like the 2 antennas "look" in the opposite direction (magnetic North Pole/South Pole of the loop).
It would work for TE012 if 2 antennas are near the small end and 2 (180°Phase shifted)antennas are near the big end if they have the same orientation.
...So what is then the difference between the contents of this folder
That's for the 64 cycle run. It matches the image, "ezz30-t04.png" and anyway, the 64 cycle run is the only one for which I have generated the z-30 slice data so far.
new-csvs
with the contents of this folder
64-cycle-run ...
Both of them are in the 64 cycle Shell 2D loop ant folder
Looks equal but with one more node of the field in z-direction (in spherical case in "r" direction, and again axial symmetric)
Question: What do E-fields and H-fields look like in TE013 mode?
Looks equal but with one more node of the field in z-direction (in spherical case in "r" direction, and again axial symmetric)
Question: What do E-fields and H-fields look like in TE013 mode?
Question: What do E-fields and H-fields look like in TE013 mode?
I was thinking of the same thing today! Rodal's drawing of the Poynting vectors (http://forum.nasaspaceflight.com/index.php?topic=38203.msg1416176#msg1416176) do not show the axial magnetic fields and transverse electric fields, so I used Eagleworks' picture.
What do we see in this cross-section animation of a TE012 mode:
(http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=38203.0;attach=1056527;image)
As I understand we are seing electric fields periodically increasing and decreasing, and their direction according to the color (towards us or towards the screen, blue then red). Am I correct?
Below I used Eagleworks picture of TE012 that shows E-field vectors (red) and H-field vectors (blue) and drew two circular electric loops, one near the big end and one near the small end of the frustum.
The AC currents in the two loops are opposite, so the axial induced magnetic fields at each instant t are in opposite directions. I think this would excite the same TE012 mode.
Each loop is a circular loop antenna and is like a one-turn electromagnetic coil. But to prevent shadowing and disturbance of the small end (we only want that shadowing near the big end) only one loop antenna would need to exist, near the big base, as in this post (http://forum.nasaspaceflight.com/index.php?topic=38203.msg1416277#msg1416277) and this one (http://forum.nasaspaceflight.com/index.php?topic=38203.msg1416337#msg1416337) by TheTraveller, where the loop antenna is located at a distance of 1/4 of the guide wavelength from the big end.
Question: What do E-fields and H-fields look like in TE013 mode?
The antennas in the sketch don't work as a loop! The loop has to be in contact to the other potential, in this case the frustum, and better the length of the loop is max a half wavelength ;)
In the sketch the wave would travel along the feed and split into two parts, this parts cancel each other at half the way along the ring.. itś like two dipoles in opposite phi directions...
The antennas in the sketch don't work as a loop! The loop has to be in contact to the other potential, in this case the frustum, and better the length of the loop is max a half wavelength ;)
In the sketch the wave would travel along the feed and split into two parts, this parts cancel each other at half the way along the ring.. itś like two dipoles in opposite phi directions...
Bigger p value leads to smaller bandwidth,Question: What do E-fields and H-fields look like in TE013 mode?
Shawyer told me he and Prof Yang moved from TM modes to TE012 and then to TE013. Understood the reason for the TM to TE mode but not the move from TE012 to TE013.
One reason I can see is designing for TE013 allows a longer frustum length and increased frustum volume, which seems to relate to higher Q.
TE013 attached.
The antennas in the sketch don't work as a loop! The loop has to be in contact to the other potential, in this case the frustum, and better the length of the loop is max a half wavelength ;)
In the sketch the wave would travel along the feed and split into two parts, this parts cancel each other at half the way along the ring.. itś like two dipoles in opposite phi directions...
I'm not sure to understand all what you said but… what do you think of this sketch (http://forum.nasaspaceflight.com/index.php?topic=38203.msg1416277#msg1416277) by TheTraveller then? Here it is reproduced:
| |
| |
| |
==>|<=====0 <---------Loop---------> 0 |
| coax |
|__________________________________ |
Bigger p value leads to smaller bandwidth,Question: What do E-fields and H-fields look like in TE013 mode?
Shawyer told me he and Prof Yang moved from TM modes to TE012 and then to TE013. Understood the reason for the TM to TE mode but not the move from TE012 to TE013.
One reason I can see is designing for TE013 allows a longer frustum length and increased frustum volume, which seems to relate to higher Q.
TE013 attached.
I have checked that experimentally(in the K-Band)
The losses are bigger because the resistive skin is greater...
It's complicated...
No. please look at the NASAloop picture. One end of the wire is in contact to the GND and that is the way it will work as a loop.The antennas in the sketch don't work as a loop! The loop has to be in contact to the other potential, in this case the frustum, and better the length of the loop is max a half wavelength ;)
In the sketch the wave would travel along the feed and split into two parts, this parts cancel each other at half the way along the ring.. itś like two dipoles in opposite phi directions...
I'm not sure to understand all what you said but… what do you think of this sketch (http://forum.nasaspaceflight.com/index.php?topic=38203.msg1416277#msg1416277) by TheTraveller then? Here it is reproduced:
| |
| |
| |
==>|<=====0 <---------Loop---------> 0 |
| coax |
|_____________________________________ |
No. please look at the NASA loop picture. One end of the wire is in contact to the GND and that is the way it will work as a loop.
The 2 ends of the loop in the picture have the same electrical potential!
The 2 ends of the loop in the picture "* Loop antenna for TE01 modes.png_thumb.jpg" have the same electrical potential!I understand now. Maybe I over-simplified by drawing but it was my intention from start to show the placement for the same kind of loop as in Eagleworks' picture, just bigger and centered around frustum's axis like in TT's sketch. I put a ring because it was plain simple, but the goal is to have a loop antenna there, with one side of the loop connected tot the ground! (and no, it should not be a coil, ok)
I understand now. Maybe I over-simplified by drawing but it was my intention from start to show the placement for the same kind of loop as in Eagleworks' picture, just bigger and centered around frustum's axis like in TT's sketch. I put a ring because it was plain simple, but the goal is to have a loop antenna there, with one side of the loop connected tot the ground! (and no, it should not be a coil, ok)
Gedankenexperiment: Using a coil and put both ends of the loop wire at the same pole of battery. How big would be the magnetic field of the coil? Right zero!
the length of the loop is max a half wavelength
Yes, if you like to excite this mode at high Q.Gedankenexperiment: Using a coil and put both ends of the loop wire at the same pole of battery. How big would be the magnetic field of the coil? Right zero!
We're discussing about a super-simple thing we shouldn't normally argue about. Of course it was never intended to work that way. One thing you said retained my attention though:the length of the loop is max a half wavelength
Since the wavelength change according to the location where it is measured (free wavelength, guide wavelength, wavelength at the big end, wavelength at the small end, wavelength at the antenna location…) which one must be taken into account to properly design the length (diameter?) of the loop antenna at this "max half-wavelength"?
I see what your doing TT but I'd wonder about ground loops with the antenna just floating out there. How do you plan to adjust for that? Are you grounding your frustum?No. please look at the NASA loop picture. One end of the wire is in contact to the GND and that is the way it will work as a loop.
The 2 ends of the loop in the picture have the same electrical potential!
My crude ascii drawing has failed to deliver. Bad TT bad.
The coax is to stop the feed from the side wall to the loop from radiating. One side of the loop antenna is attached to the coax hot centre feed line and the other side of the loop antenna to the coax shield.
So the same as the NASA picture, just bigger in diameter and with the short section of 2 parallel wires replaced with coax.
If I get the loop diameter and distance from the big end right, should do an excellent job at exciting TE013 mode.
I see what your doing TT but I'd wonder about ground loops with the antenna just floating out there. How do you plan to adjust for that? Are you grounding your frustum?No. please look at the NASA loop picture. One end of the wire is in contact to the GND and that is the way it will work as a loop.
The 2 ends of the loop in the picture have the same electrical potential!
My crude ascii drawing has failed to deliver. Bad TT bad.
The coax is to stop the feed from the side wall to the loop from radiating. One side of the loop antenna is attached to the coax hot centre feed line and the other side of the loop antenna to the coax shield.
So the same as the NASA picture, just bigger in diameter and with the short section of 2 parallel wires replaced with coax.
If I get the loop diameter and distance from the big end right, should do an excellent job at exciting TE013 mode.
AKA GND isn't always ground.I see what your doing TT but I'd wonder about ground loops with the antenna just floating out there. How do you plan to adjust for that? Are you grounding your frustum?No. please look at the NASA loop picture. One end of the wire is in contact to the GND and that is the way it will work as a loop.
The 2 ends of the loop in the picture have the same electrical potential!
My crude ascii drawing has failed to deliver. Bad TT bad.
The coax is to stop the feed from the side wall to the loop from radiating. One side of the loop antenna is attached to the coax hot centre feed line and the other side of the loop antenna to the coax shield.
So the same as the NASA picture, just bigger in diameter and with the short section of 2 parallel wires replaced with coax.
If I get the loop diameter and distance from the big end right, should do an excellent job at exciting TE013 mode.
The chassis of the magnetron is one of the two potential (aka GND) ;)
The other switch between +Volts and -Volts against GND.
Right :) The Voltage difference predicts the current flow.AKA GND isn't always ground.I see what your doing TT but I'd wonder about ground loops with the antenna just floating out there. How do you plan to adjust for that? Are you grounding your frustum?No. please look at the NASA loop picture. One end of the wire is in contact to the GND and that is the way it will work as a loop.
The 2 ends of the loop in the picture have the same electrical potential!
My crude ascii drawing has failed to deliver. Bad TT bad.
The coax is to stop the feed from the side wall to the loop from radiating. One side of the loop antenna is attached to the coax hot centre feed line and the other side of the loop antenna to the coax shield.
So the same as the NASA picture, just bigger in diameter and with the short section of 2 parallel wires replaced with coax.
If I get the loop diameter and distance from the big end right, should do an excellent job at exciting TE013 mode.
The chassis of the magnetron is one of the two potential (aka GND) ;)
The other switch between +Volts and -Volts against GND.
https://en.wikipedia.org/wiki/Ground_loop_(electricity)
And that difference in potentials will and can change in a oscillatory system and cause the ground plane to oscillate with the conductive harmonic path lengths between the grounds.Right :) The Voltage difference predicts the current flowAKA GND isn't always ground.I see what your doing TT but I'd wonder about ground loops with the antenna just floating out there. How do you plan to adjust for that? Are you grounding your frustum?No. please look at the NASA loop picture. One end of the wire is in contact to the GND and that is the way it will work as a loop.
The 2 ends of the loop in the picture have the same electrical potential!
My crude ascii drawing has failed to deliver. Bad TT bad.
The coax is to stop the feed from the side wall to the loop from radiating. One side of the loop antenna is attached to the coax hot centre feed line and the other side of the loop antenna to the coax shield.
So the same as the NASA picture, just bigger in diameter and with the short section of 2 parallel wires replaced with coax.
If I get the loop diameter and distance from the big end right, should do an excellent job at exciting TE013 mode.
The chassis of the magnetron is one of the two potential (aka GND) ;)
The other switch between +Volts and -Volts against GND.
https://en.wikipedia.org/wiki/Ground_loop_(electricity)
Since the wavelength change according to the location where it is measured (free wavelength, guide wavelength, wavelength at the big end, wavelength at the small end, wavelength at the antenna location…) which one must be taken into account to properly design the length (diameter?) of the loop antenna at this "max half-wavelength"?
QuoteSince the wavelength change according to the location where it is measured (free wavelength, guide wavelength, wavelength at the big end, wavelength at the small end, wavelength at the antenna location…) which one must be taken into account to properly design the length (diameter?) of the loop antenna at this "max half-wavelength"?
Multiple antenna's? Use only the one you happen to need at that particular moment.
...So what is then the difference between the contents of this folder
That's for the 64 cycle run. It matches the image, "ezz30-t04.png" and anyway, the 64 cycle run is the only one for which I have generated the z-30 slice data so far.
new-csvs
with the contents of this folder
64-cycle-run ...
Both of them are in the 64 cycle Shell 2D loop ant folder
Are they in fact different? They shouldn't be. 64-cycle run csv's were made prior to changing the magnitude range of the .png files, and the new-csvs data was made in the process of making the .pngs with the new magnitude ranges. I don't have any efficient way to check whether or not they are in fact the same so I uploaded them in case you wanted to check. If they are in fact different then there is something going on with the h5totxt program that I don't understand.
...So what is then the difference between the contents of this folder
That's for the 64 cycle run. It matches the image, "ezz30-t04.png" and anyway, the 64 cycle run is the only one for which I have generated the z-30 slice data so far.
new-csvs
with the contents of this folder
64-cycle-run ...
Both of them are in the 64 cycle Shell 2D loop ant folder
Are they in fact different? They shouldn't be. 64-cycle run csv's were made prior to changing the magnitude range of the .png files, and the new-csvs data was made in the process of making the .pngs with the new magnitude ranges. I don't have any efficient way to check whether or not they are in fact the same so I uploaded them in case you wanted to check. If they are in fact different then there is something going on with the h5totxt program that I don't understand.
The reason why I had asked for the "location 30" runs to be done for a 32 cycle instead of a 64 cycle is in order to find out whether the 10,000 fold increase in stresses and force is mainly due to the doubling of the running time or whether it is mainly due to the TE012 mode instead of a TM mode as in previous runs.
In order to find out the main reason for this 10,000 fold increase in stress and force we still need the same information to be run for a 32 cycle run to compare with the 64 cycle run.
And that difference in potentials will and can change in a oscillatory system and cause the ground plane to oscillate with the conductive harmonic path lengths between the grounds.Right :) The Voltage difference predicts the current flowAKA GND isn't always ground.I see what your doing TT but I'd wonder about ground loops with the antenna just floating out there. How do you plan to adjust for that? Are you grounding your frustum?No. please look at the NASA loop picture. One end of the wire is in contact to the GND and that is the way it will work as a loop.
The 2 ends of the loop in the picture have the same electrical potential!
My crude ascii drawing has failed to deliver. Bad TT bad.
The coax is to stop the feed from the side wall to the loop from radiating. One side of the loop antenna is attached to the coax hot centre feed line and the other side of the loop antenna to the coax shield.
So the same as the NASA picture, just bigger in diameter and with the short section of 2 parallel wires replaced with coax.
If I get the loop diameter and distance from the big end right, should do an excellent job at exciting TE013 mode.
The chassis of the magnetron is one of the two potential (aka GND) ;)
The other switch between +Volts and -Volts against GND.
https://en.wikipedia.org/wiki/Ground_loop_(electricity)
I see what your doing TT but I'd wonder about ground loops with the antenna just floating out there. How do you plan to adjust for that? Are you grounding your frustum?No. please look at the NASA loop picture. One end of the wire is in contact to the GND and that is the way it will work as a loop.
The 2 ends of the loop in the picture have the same electrical potential!
My crude ascii drawing has failed to deliver. Bad TT bad.
The coax is to stop the feed from the side wall to the loop from radiating. One side of the loop antenna is attached to the coax hot centre feed line and the other side of the loop antenna to the coax shield.
So the same as the NASA picture, just bigger in diameter and with the short section of 2 parallel wires replaced with coax.
If I get the loop diameter and distance from the big end right, should do an excellent job at exciting TE013 mode.
I see what your doing TT but I'd wonder about ground loops with the antenna just floating out there. How do you plan to adjust for that? Are you grounding your frustum?No. please look at the NASA loop picture. One end of the wire is in contact to the GND and that is the way it will work as a loop.
The 2 ends of the loop in the picture have the same electrical potential!
My crude ascii drawing has failed to deliver. Bad TT bad.
The coax is to stop the feed from the side wall to the loop from radiating. One side of the loop antenna is attached to the coax hot centre feed line and the other side of the loop antenna to the coax shield.
So the same as the NASA picture, just bigger in diameter and with the short section of 2 parallel wires replaced with coax.
If I get the loop diameter and distance from the big end right, should do an excellent job at exciting TE013 mode.
On the top of my rotary table but under all the equipment will be a thin copper layer that will serve as my reference ground plane. Everything will be grounded to this high frequency ground reference plane.
Additionally all external wiring will be shielded and will use a 2 turn ferrite (shielded cable will circle through the ferrite donut twice) to filter out high freq noise on the shield grounds.
Of course all power leads will have high frequency decoupling capacitors and ferrite filters.
Anybody who has ever designed and debugged a high frequency pcb knows the value of a solid copper ground plane.
So yes ground loops can be a problem but not if using a large area solid copper ground plane with additional high frequency decoupling capacitors and ferrite donuts.
QuoteSince the wavelength change according to the location where it is measured (free wavelength, guide wavelength, wavelength at the big end, wavelength at the small end, wavelength at the antenna location…) which one must be taken into account to properly design the length (diameter?) of the loop antenna at this "max half-wavelength"?
Multiple antenna's? Use only the one you happen to need at that particular moment.
http://forum.nasaspaceflight.com/index.php?topic=38203.msg1416759#msg1416759
Got me thinking the quartz rod through the center could support some mode filters if needed.
Nice read Doc.
Shell
http://forum.nasaspaceflight.com/index.php?topic=38203.msg1416759#msg1416759
Got me thinking the quartz rod through the center could support some mode filters if needed.
Nice read Doc.
Shell
...you are thinking about feeding the magnetron Rf into your frustum via a waveguide and not direct inject it. My concern with the waveguide is the frustum will then have an input bandwidth that may not wide enough to accept most of the magnetron output bandwidth. Surley you don't want a Q of 50 like Tajmar used? How do you intend to deal with using a waveguide feed, limited input bandwidth and getting all your magnetron energy inside your frustum?
http://forum.nasaspaceflight.com/index.php?topic=38203.msg1416759#msg1416759
Got me thinking the quartz rod through the center could support some mode filters if needed.
Nice read Doc.
Shell
What is your estimated max averaged frustum surface temperature when pumping your 800 watts of Rf into the frustum?
From that temperature, how much will your copper end plate diameters grow and how much longer will your copper frustum grow?
You can dramatically increase the surface emissivity by around 5x to 10x by painting the outside surface with a high carbon black paint. This higher thermal emissivity will very significantly reduce your frustum temperature rise and significantly reduce any thermal expansion.
As copper expands 0.0166mm per deg K per m, increasing the surface emissivity 5x could really work wonders for limiting thermal expansion.
On another subject, I see you are thinking about feeding the magnetron Rf into your frustum via a waveguide and not direct inject it. My concern with the waveguide is the frustum will then have an input bandwidth that may not wide enough to accept most of the magnetron output bandwidth. Surley you don't want a Q of 50 like Tajmar used? How do you intend to deal with using a waveguide feed, limited input bandwidth and getting all your magnetron energy inside your frustum?
...
On the top of my rotary table but under all the equipment will be a thin copper layer that will serve as my reference ground plane. Everything will be grounded to this high frequency ground reference plane.
...
Anybody who has ever designed and debugged a high frequency pcb knows the value of a solid copper ground plane.
So yes ground loops can be a problem but not if using a large area solid copper ground plane with additional high frequency decoupling capacitors and ferrite donuts.
...
On the top of my rotary table but under all the equipment will be a thin copper layer that will serve as my reference ground plane. Everything will be grounded to this high frequency ground reference plane.
...
Anybody who has ever designed and debugged a high frequency pcb knows the value of a solid copper ground plane.
So yes ground loops can be a problem but not if using a large area solid copper ground plane with additional high frequency decoupling capacitors and ferrite donuts.
At 2.4 GHz ferrite donuts are not needed. Instead an air core inductor inline with each power lead that is not at ground potential is all that is needed. Filter caps on either side of the inductor are used to prevent voltage sag from current transients. They are a high impedance path to RF. But since the inductor only needs to be a few nH. caps are not needed.
The fustrum is your ground plane. No thin copper sheet is needed. Any conductors going to this ersatz ground plane will be many wavelengths long. So it is impossible to make this copper sheet a ground at RF.
The biggest problem with driving a fustrum from a coax feed is matching the loop inside the cavity. It is virtually impossible to make the loop exactly the right length so it will almost never be a 50 Ohms resistive load at the frequency used. It will always be capacitive because of the adjacent cavity walls. So a large part of the RF sent into the cavity will just get reflected back on the shield. Ferrites are only useful up to VHF frequencies so putting ferrite donuts on the coax will have no effect. Maybe coiling the coax will help but a lot of RF will still get radiated because of the mismatch. Matching networks can be used but in that case the return wave is just dissipated in the matching network.
The biggest problem with a frustum is gettin frust that other people think is real.
http://forum.nasaspaceflight.com/index.php?topic=38203.msg1416759#msg1416759Surley you don't want a Q of 50 like Tajmar used? How do you intend to deal with using a waveguide feed, limited input bandwidth and getting all your magnetron energy inside your frustum?
Got me thinking the quartz rod through the center could support some mode filters if needed.
Nice read Doc.
Shell
The biggest problem with a frustum is gettin frust that other people think is real.I can get all the frust you want, it's thust that is costly.
Tajmar had measured loaded Q by using a Z=50 Ohm port of a network analyzer (S11). They simply use the 3dB bandwidth. They did not derive the unloaded Q!http://forum.nasaspaceflight.com/index.php?topic=38203.msg1416759#msg1416759
Got me thinking the quartz rod through the center could support some mode filters if needed.
Nice read Doc.
Shell
...you are thinking about feeding the magnetron Rf into your frustum via a waveguide and not direct inject it. My concern with the waveguide is the frustum will then have an input bandwidth that may not wide enough to accept most of the magnetron output bandwidth. Surley you don't want a Q of 50 like Tajmar used? How do you intend to deal with using a waveguide feed, limited input bandwidth and getting all your magnetron energy inside your frustum?
True. But comparing different characteristics of transmission lines one has to trade off:
Characteristic Coaxial Waveguide Winner
Unloaded Q Medium High Waveguide
Power Capability Medium High Waveguide
Bandwidth Large Small Coaxial
Tajmar had measured loaded Q by using a Z=50 Ohm port of a network analyzer (S11). They simply use the 3dB bandwidth. They did not derive the unloaded Q!
The plot in the paper shows S11 Measurement. (headline of the plot)Tajmar had measured loaded Q by using a Z=50 Ohm port of a network analyzer (S11). They simply use the 3dB bandwidth. They did not derive the unloaded Q!
What is the "load" on an 0 port EMDrive resonant cavity?
As far as I understand the topic, there is no load on a EMDrive cavity. It is a 0 port resonant cavity with a Rf feed point but no input nor output ports. Measuring the cavity Q via the Rf feed 3dB down points from the max return loss dB is the cavities unloaded Q.
This method to measure unloaded 0 port EMDrive resonant cavity Q is that used by Eagleworks, Shawyer, Prof Yang and Prof Tajmar.
Tajmar was trying to excite the TE01 mode
The plot in the paper shows S11 Measurement. (headline of the plot)Tajmar had measured loaded Q by using a Z=50 Ohm port of a network analyzer (S11). They simply use the 3dB bandwidth. They did not derive the unloaded Q!
What is the "load" on an 0 port EMDrive resonant cavity?
As far as I understand the topic, there is no load on a EMDrive cavity. It is a 0 port resonant cavity with a Rf feed point but no input nor output ports. Measuring the cavity Q via the Rf feed 3dB down points from the max return loss dB is the cavities unloaded Q.
This method to measure unloaded 0 port EMDrive resonant cavity Q is that used by Eagleworks, Shawyer, Prof Yang and Prof Tajmar.
I think they had measured the S11 and after that, the magnetron was connected.
IMHO the simplest way is to use a coaxial to waveguide connector instead the magnetron for the measurements.The plot in the paper shows S11 Measurement. (headline of the plot)Tajmar had measured loaded Q by using a Z=50 Ohm port of a network analyzer (S11). They simply use the 3dB bandwidth. They did not derive the unloaded Q!
What is the "load" on an 0 port EMDrive resonant cavity?
As far as I understand the topic, there is no load on a EMDrive cavity. It is a 0 port resonant cavity with a Rf feed point but no input nor output ports. Measuring the cavity Q via the Rf feed 3dB down points from the max return loss dB is the cavities unloaded Q.
This method to measure unloaded 0 port EMDrive resonant cavity Q is that used by Eagleworks, Shawyer, Prof Yang and Prof Tajmar.
I think they had measured the S11 and after that, the magnetron was connected.
That Tajmar cavity has no holes in it, other than the waveguide feed port in the frustum side wall and at the other end, the hole to allow the magnetron antenna to get inside the connecting waveguide.
Which would suggest they removed the magnetron and built a sample probe to fit in the magnetron hole and measured the S11 return loss dB curve, which Tajmar shows in the paper and used the 3bd down points to calc the bandwidth and unloaded cavity Q.
If you look closely at the vac photographs, you can see the magnetron is sometimes on one side or the other of the frustum ends. Would guess they rotated the magnetron and it's coupling waveguide assembly to make placing it on the vac table more stable.
And no, they measured Q not Q_0, its not possible to measure Q_0 directly, one have to derive/calculate that from the complex measurement data.
Only for the coupling factor equals to 1 the full 1/sqrt(2) BW is direct usable. The coupling factor can be derived from the measurements. Sorry the paper is german but i never find a better instructions manual. :)And no, they measured Q not Q_0, its not possible to measure Q_0 directly, one have to derive/calculate that from the complex measurement data.
Thanks for the paper.
After going through it side by side to a google translate version it seems you are saying the unloaded cavity Q is:
Q0 = (2 * Pi * Stored Energy) / Energy loss per cycle
and that the Q0 value can't be accurately measured via S11 max return loss dB at the 3dB down points?
Correct?
Back from the Dresden front! Martin Tajmar sent me an email today where he says he measured the internal height of his frustum. It seems he went to the lab to measure it himself before his student came back from holidays ;)
Quote from: Martin Tajmar
I measured it: the internal height is 72.8 mm (after adjustment for better resonance). Between the Cavity and the waveguide we used an adapter. The measures are all correct. We simulated it in COMSOL and also Shawyer with his calculation program assured us that the dimensions we used were correct.
So the official internal dimensions from Tajmar are now:
Db = 108.2 mm
Ds = 77 mm
Height = 72.8 mm
Can you guys verify this cavity resonates in your frustumator software? :)
EDIT: A WR340 waveguide measures 86.36 x 43.18 mm so Tajmar used a coupling adapter reducing the waveguide.
with spherical ends, what mode shape did Tajmar excite?[/b]
If this is true (TM010) i don't understand the orientation of the coupling waveguide, its the complete wrong orientation to excite this mode! May be thats why they have so small Q value ????????????Quote from: flux_capacitor http://forum.nasaspaceflight.com/index.php?topic=37642.msg1412868#msg1412868Back from the Dresden front! Martin Tajmar sent me an email today where he says he measured the internal height of his frustum. It seems he went to the lab to measure it himself before his student came back from holidays ;)
Quote from: Martin Tajmar
I measured it: the internal height is 72.8 mm (after adjustment for better resonance). Between the Cavity and the waveguide we used an adapter. The measures are all correct. We simulated it in COMSOL and also Shawyer with his calculation program assured us that the dimensions we used were correct.
So the official internal dimensions from Tajmar are now:
Db = 108.2 mm
Ds = 77 mm
Height = 72.8 mm
Can you guys verify this cavity resonates in your frustumator software? :)
EDIT: A WR340 waveguide measures 86.36 x 43.18 mm so Tajmar used a coupling adapter reducing the waveguide.
http://forum.nasaspaceflight.com/index.php?topic=37642.msg1412868#msg1412868
According to TheTraveller's spreadsheet, based on those dimensions
Db = 108.2 mm
Ds = 77 mm
Height = 72.8 mm
with spherical ends, what mode shape did Tajmar excite?
According to my calculations it is (the equivalent of cylindrical mode) TM010 at ~2.45 GHz (*)
the lowest transverse magnetic mode possible.
I have modified the EM Drive wiki (that had TE111 based on a longer length of 0.1008 m instead of 0.0728m, and Db=0.1062m instead of 0.1082m and Ds=0.075m instead of 0.077m) to show these dimensions and mode shape.
_____________
(*) I write "the equivalent" because this mode is not constant in the longitudinal direction. It is impossible for a mode to be constant in the longitudinal direction for a truncated cone. I write "the equivalent" because this is the lowest TM mode for the truncated cone. It is a degenerate mode that corresponds to TM010 for a cylinder.
with spherical ends, what mode shape did Tajmar excite?[/b]
Where did Prof Tajmar say the end plates had a spherical curve?
Did I miss some info here on the forum as I can't find any such mention in the original or updated paper?
If this is true (TM010) i don't understand the orientation of the coupling waveguide, its the complete wrong orientation to excite this mode! May be thats why they have so small Q value ????????????Quote from: flux_capacitor http://forum.nasaspaceflight.com/index.php?topic=37642.msg1412868#msg1412868Back from the Dresden front! Martin Tajmar sent me an email today where he says he measured the internal height of his frustum. It seems he went to the lab to measure it himself before his student came back from holidays ;)
Quote from: Martin Tajmar
I measured it: the internal height is 72.8 mm (after adjustment for better resonance). Between the Cavity and the waveguide we used an adapter. The measures are all correct. We simulated it in COMSOL and also Shawyer with his calculation program assured us that the dimensions we used were correct.
So the official internal dimensions from Tajmar are now:
Db = 108.2 mm
Ds = 77 mm
Height = 72.8 mm
Can you guys verify this cavity resonates in your frustumator software? :)
EDIT: A WR340 waveguide measures 86.36 x 43.18 mm so Tajmar used a coupling adapter reducing the waveguide.
http://forum.nasaspaceflight.com/index.php?topic=37642.msg1412868#msg1412868
According to TheTraveller's spreadsheet, based on those dimensions
Db = 108.2 mm
Ds = 77 mm
Height = 72.8 mm
with spherical ends, what mode shape did Tajmar excite?
According to my calculations it is (the equivalent of cylindrical mode) TM010 at ~2.45 GHz (*)
the lowest transverse magnetic mode possible.
I have modified the EM Drive wiki (that had TE111 based on a longer length of 0.1008 m instead of 0.0728m, and Db=0.1062m instead of 0.1082m and Ds=0.075m instead of 0.077m) to show these dimensions and mode shape.
_____________
(*) I write "the equivalent" because this mode is not constant in the longitudinal direction. It is impossible for a mode to be constant in the longitudinal direction for a truncated cone. I write "the equivalent" because this is the lowest TM mode for the truncated cone. It is a degenerate mode that corresponds to TM010 for a cylinder.
In a cylinder this mode do not depend on the length.
Only for the coupling factor equals to 1 the full 1/sqrt(2) BW is direct usable. The coupling factor can be derived from the measurements. Sorry the paper is german but i never find a better instructions manual. :)And no, they measured Q not Q_0, its not possible to measure Q_0 directly, one have to derive/calculate that from the complex measurement data.
Thanks for the paper.
After going through it side by side to a google translate version it seems you are saying the unloaded cavity Q is:
Q0 = (2 * Pi * Stored Energy) / Energy loss per cycle
and that the Q0 value can't be accurately measured via S11 max return loss dB at the 3dB down points?
Correct?
Please look at page 21 in the green box..
And Q_0=Q*(1+coupling factor)
...
On the top of my rotary table but under all the equipment will be a thin copper layer that will serve as my reference ground plane. Everything will be grounded to this high frequency ground reference plane.
...
Anybody who has ever designed and debugged a high frequency pcb knows the value of a solid copper ground plane.
So yes ground loops can be a problem but not if using a large area solid copper ground plane with additional high frequency decoupling capacitors and ferrite donuts.
At 2.4 GHz ferrite donuts are not needed. Instead an air core inductor inline with each power lead that is not at ground potential is all that is needed. Filter caps on either side of the inductor are used to prevent voltage sag from current transients. They are a high impedance path to RF. But since the inductor only needs to be a few nH. caps are not needed.
The fustrum is your ground plane. No thin copper sheet is needed. Any conductors going to this ersatz ground plane will be many wavelengths long. So it is impossible to make this copper sheet a ground at RF.
The biggest problem with driving a fustrum from a coax feed is matching the loop inside the cavity. It is virtually impossible to make the loop exactly the right length so it will almost never be a 50 Ohms resistive load at the frequency used. It will always be capacitive because of the adjacent cavity walls. So a large part of the RF sent into the cavity will just get reflected back on the shield. Ferrites are only useful up to VHF frequencies so putting ferrite donuts on the coax will have no effect. Maybe coiling the coax will help but a lot of RF will still get radiated because of the mismatch. Matching networks can be used but in that case the return wave is just dissipated in the matching network.
My recollection is that the information (spherical ends and dimensions) is the product of personal e-mails exchanged between FluxCapacitor and Tajmar, if my memory is correct.
FluxCapacitor to confirm...
...
On the top of my rotary table but under all the equipment will be a thin copper layer that will serve as my reference ground plane. Everything will be grounded to this high frequency ground reference plane.
...
Anybody who has ever designed and debugged a high frequency pcb knows the value of a solid copper ground plane.
So yes ground loops can be a problem but not if using a large area solid copper ground plane with additional high frequency decoupling capacitors and ferrite donuts.
At 2.4 GHz ferrite donuts are not needed. Instead an air core inductor inline with each power lead that is not at ground potential is all that is needed. Filter caps on either side of the inductor are used to prevent voltage sag from current transients. They are a high impedance path to RF. But since the inductor only needs to be a few nH. caps are not needed.
The fustrum is your ground plane. No thin copper sheet is needed. Any conductors going to this ersatz ground plane will be many wavelengths long. So it is impossible to make this copper sheet a ground at RF.
The biggest problem with driving a fustrum from a coax feed is matching the loop inside the cavity. It is virtually impossible to make the loop exactly the right length so it will almost never be a 50 Ohms resistive load at the frequency used. It will always be capacitive because of the adjacent cavity walls. So a large part of the RF sent into the cavity will just get reflected back on the shield. Ferrites are only useful up to VHF frequencies so putting ferrite donuts on the coax will have no effect. Maybe coiling the coax will help but a lot of RF will still get radiated because of the mismatch. Matching networks can be used but in that case the return wave is just dissipated in the matching network.
Quite right - there is a very significant difference between power grounding and RF grounding. At the appoximately 12cm wavelengths most folks are working with (2.45 Ghz or thereabout) any ground lead longer than about 6cm is also a pretty decent radiator. Google RF grounding - there is wealth of info about it. Power and safety ground are also very important.
Just a comment from those using loop antennas. Loop antennas are magnetic antenna and work differently from antennas like dipoles and monopoles. The common circumference for loop antennas is on the order of 1 lambda not lambda/2. A half wavelength circmumference will have a VERY high input impedance and will be hard to couple. A full wavelength loop will be significantly closer to 50 ohms, although wavelength variations due to excited mode and geometry of the cavity will also have significant effects. I will try to model up some example loops and patterns later today/tonight when I have access to the software.
Herman
TE010 left out a 0 in the middle of the night. It was the best gesstimate.My recollection is that the information (spherical ends and dimensions) is the product of personal e-mails exchanged between FluxCapacitor and Tajmar, if my memory is correct.
FluxCapacitor to confirm...
Found it.
http://forum.nasaspaceflight.com/index.php?topic=37642.msg1411835#msg1411835
Spherical end plates seems so wrong when Prof Tajmar's frustum need a low Q to be able to accept all the wide band Rf the magnetron can produce. Something is not right.
...
On the top of my rotary table but under all the equipment will be a thin copper layer that will serve as my reference ground plane. Everything will be grounded to this high frequency ground reference plane.
...
Anybody who has ever designed and debugged a high frequency pcb knows the value of a solid copper ground plane.
So yes ground loops can be a problem but not if using a large area solid copper ground plane with additional high frequency decoupling capacitors and ferrite donuts.
At 2.4 GHz ferrite donuts are not needed. Instead an air core inductor inline with each power lead that is not at ground potential is all that is needed. Filter caps on either side of the inductor are used to prevent voltage sag from current transients. They are a high impedance path to RF. But since the inductor only needs to be a few nH. caps are not needed.
The fustrum is your ground plane. No thin copper sheet is needed. Any conductors going to this ersatz ground plane will be many wavelengths long. So it is impossible to make this copper sheet a ground at RF.
The biggest problem with driving a fustrum from a coax feed is matching the loop inside the cavity. It is virtually impossible to make the loop exactly the right length so it will almost never be a 50 Ohms resistive load at the frequency used. It will always be capacitive because of the adjacent cavity walls. So a large part of the RF sent into the cavity will just get reflected back on the shield. Ferrites are only useful up to VHF frequencies so putting ferrite donuts on the coax will have no effect. Maybe coiling the coax will help but a lot of RF will still get radiated because of the mismatch. Matching networks can be used but in that case the return wave is just dissipated in the matching network.
Quite right - there is a very significant difference between power grounding and RF grounding. At the appoximately 12cm wavelengths most folks are working with (2.45 Ghz or thereabout) any ground lead longer than about 6cm is also a pretty decent radiator. Google RF grounding - there is wealth of info about it. Power and safety ground are also very important.
Just a comment from those using loop antennas. Loop antennas are magnetic antenna and work differently from antennas like dipoles and monopoles. The common circumference for loop antennas is on the order of 1 lambda not lambda/2. A half wavelength circmumference will have a VERY high input impedance and will be hard to couple. A full wavelength loop will be significantly closer to 50 ohms, although wavelength variations due to excited mode and geometry of the cavity will also have significant effects. I will try to model up some example loops and patterns later today/tonight when I have access to the software.
Herman
It will be interesting to experiment with loops versus radomes and other monopoles. Loops are difficult to transition from a magnetron source, guess its why I decided to use the factory 'dome....
On the top of my rotary table but under all the equipment will be a thin copper layer that will serve as my reference ground plane. Everything will be grounded to this high frequency ground reference plane.
...
Anybody who has ever designed and debugged a high frequency pcb knows the value of a solid copper ground plane.
So yes ground loops can be a problem but not if using a large area solid copper ground plane with additional high frequency decoupling capacitors and ferrite donuts.
At 2.4 GHz ferrite donuts are not needed. Instead an air core inductor inline with each power lead that is not at ground potential is all that is needed. Filter caps on either side of the inductor are used to prevent voltage sag from current transients. They are a high impedance path to RF. But since the inductor only needs to be a few nH. caps are not needed.
The fustrum is your ground plane. No thin copper sheet is needed. Any conductors going to this ersatz ground plane will be many wavelengths long. So it is impossible to make this copper sheet a ground at RF.
The biggest problem with driving a fustrum from a coax feed is matching the loop inside the cavity. It is virtually impossible to make the loop exactly the right length so it will almost never be a 50 Ohms resistive load at the frequency used. It will always be capacitive because of the adjacent cavity walls. So a large part of the RF sent into the cavity will just get reflected back on the shield. Ferrites are only useful up to VHF frequencies so putting ferrite donuts on the coax will have no effect. Maybe coiling the coax will help but a lot of RF will still get radiated because of the mismatch. Matching networks can be used but in that case the return wave is just dissipated in the matching network.
Quite right - there is a very significant difference between power grounding and RF grounding. At the appoximately 12cm wavelengths most folks are working with (2.45 Ghz or thereabout) any ground lead longer than about 6cm is also a pretty decent radiator. Google RF grounding - there is wealth of info about it. Power and safety ground are also very important.
Just a comment from those using loop antennas. Loop antennas are magnetic antenna and work differently from antennas like dipoles and monopoles. The common circumference for loop antennas is on the order of 1 lambda not lambda/2. A half wavelength circmumference will have a VERY high input impedance and will be hard to couple. A full wavelength loop will be significantly closer to 50 ohms, although wavelength variations due to excited mode and geometry of the cavity will also have significant effects. I will try to model up some example loops and patterns later today/tonight when I have access to the software.
Herman
1) The force magnitude is a whooping 10,000 times higher than for previous cases.
Prof Yang has shown the end plate bounce Force is very much larger if the H field (TE mode) is doing the bounce than if the E field (TM mode) is doing the bounce.
@ Dr. Rodal,
I uploaded the csv files of slice z-30 for the 32 cycle Yang-Shell run, here:
https://drive.google.com/folderview?id=0B1XizxEfB23tfnJnUUVsTUR6ZmdkRnZFY1l5SnFNT05ZUEdRWHQ5VzJ4cFlneE5WOFZyQWc&usp=sharing (https://drive.google.com/folderview?id=0B1XizxEfB23tfnJnUUVsTUR6ZmdkRnZFY1l5SnFNT05ZUEdRWHQ5VzJ4cFlneE5WOFZyQWc&usp=sharing)
Let me know if there are any problems with the csvs. The pngs will follow later.
Whew, honestly the 10k increase was a little unnerving. 2-3x I could deal with and 20 is still high but real world testing will show the true numbers.@ Dr. Rodal,
I uploaded the csv files of slice z-30 for the 32 cycle Yang-Shell run, here:
https://drive.google.com/folderview?id=0B1XizxEfB23tfnJnUUVsTUR6ZmdkRnZFY1l5SnFNT05ZUEdRWHQ5VzJ4cFlneE5WOFZyQWc&usp=sharing (https://drive.google.com/folderview?id=0B1XizxEfB23tfnJnUUVsTUR6ZmdkRnZFY1l5SnFNT05ZUEdRWHQ5VzJ4cFlneE5WOFZyQWc&usp=sharing)
Let me know if there are any problems with the csvs. The pngs will follow later.
Preliminary assessment of these data reveals that the roughly 10,000 fold increase in force of the TE mode case at 64 cycles compared to the TM mode at 32 cycles is due to:
1) Doubling the run time from the time that the RF feed was turned ON to time OFF: roughly 500 times increase in force
2) TE instead of TM mode: roughly 20 times increase in force
Only for the coupling factor equals to 1 the full 1/sqrt(2) BW is direct usable. The coupling factor can be derived from the measurements. Sorry the paper is german but i never find a better instructions manual. :)And no, they measured Q not Q_0, its not possible to measure Q_0 directly, one have to derive/calculate that from the complex measurement data.
Thanks for the paper.
After going through it side by side to a google translate version it seems you are saying the unloaded cavity Q is:
Q0 = (2 * Pi * Stored Energy) / Energy loss per cycle
and that the Q0 value can't be accurately measured via S11 max return loss dB at the 3dB down points?
Correct?
Please look at page 21 in the green box..
And Q_0=Q*(1+coupling factor)
That paper is GOLD, even if it is in technical German. Split screening with the Google translation it reads fine.
Nice how it ties together the coupling factor k, the reflection coefficient p and the various forms of Q.
I note the reflection coefficient p can be calculated from the S11 max return loss dB at resonance and from that p value, the coupling factor k can be calculated and from that k value, the unloaded cavity Q can be calculated from the Q measured via the 3dB off the max return loss dB.
Correct?
@ Dr. Rodal,
I uploaded the csv files of slice z-30 for the 32 cycle Yang-Shell run, here:
https://drive.google.com/folderview?id=0B1XizxEfB23tfnJnUUVsTUR6ZmdkRnZFY1l5SnFNT05ZUEdRWHQ5VzJ4cFlneE5WOFZyQWc&usp=sharing (https://drive.google.com/folderview?id=0B1XizxEfB23tfnJnUUVsTUR6ZmdkRnZFY1l5SnFNT05ZUEdRWHQ5VzJ4cFlneE5WOFZyQWc&usp=sharing)
Let me know if there are any problems with the csvs. The pngs will follow later.
Preliminary assessment of these data reveals that the roughly 10,000 fold increase in force of the TE mode case at 64 cycles compared to the TM mode at 32 cycles is due to:
1) Doubling the run time from the time that the RF feed was turned ON to time OFF: roughly 500 times increase in force
2) TE instead of TM mode: roughly 20 times increase in force
@ Dr. Rodal,
I uploaded the csv files of slice z-30 for the 32 cycle Yang-Shell run, here:
https://drive.google.com/folderview?id=0B1XizxEfB23tfnJnUUVsTUR6ZmdkRnZFY1l5SnFNT05ZUEdRWHQ5VzJ4cFlneE5WOFZyQWc&usp=sharing (https://drive.google.com/folderview?id=0B1XizxEfB23tfnJnUUVsTUR6ZmdkRnZFY1l5SnFNT05ZUEdRWHQ5VzJ4cFlneE5WOFZyQWc&usp=sharing)
Let me know if there are any problems with the csvs. The pngs will follow later.
Preliminary assessment of these data reveals that the roughly 10,000 fold increase in force of the TE mode case at 64 cycles compared to the TM mode at 32 cycles is due to:
1) Doubling the run time from the time that the RF feed was turned ON to time OFF: roughly 500 times increase in force
2) TE instead of TM mode: roughly 20 times increase in force
...Whew, honestly the 10k increase was a little unnerving. 2-3x I could deal with and 20 is still high but real world testing will show the true numbers...
The thrust curves demonstrate that on the surfaces of the major and minor end plates the magnetic thrust (due to TE modes) is two orders of magnitude higher than the electric thrust (due to TM modes)[quotes added by me for clarity, bold added for emphasis]
Thank you for posting these numbers again, we all forget so quickly.@ Dr. Rodal,
I uploaded the csv files of slice z-30 for the 32 cycle Yang-Shell run, here:
https://drive.google.com/folderview?id=0B1XizxEfB23tfnJnUUVsTUR6ZmdkRnZFY1l5SnFNT05ZUEdRWHQ5VzJ4cFlneE5WOFZyQWc&usp=sharing (https://drive.google.com/folderview?id=0B1XizxEfB23tfnJnUUVsTUR6ZmdkRnZFY1l5SnFNT05ZUEdRWHQ5VzJ4cFlneE5WOFZyQWc&usp=sharing)
Let me know if there are any problems with the csvs. The pngs will follow later.
Preliminary assessment of these data reveals that the roughly 10,000 fold increase in force of the TE mode case at 64 cycles compared to the TM mode at 32 cycles is due to:
1) Doubling the run time from the time that the RF feed was turned ON to time OFF: roughly 500 times increase in force
2) TE instead of TM mode: roughly 20 times increase in force...Whew, honestly the 10k increase was a little unnerving. 2-3x I could deal with and 20 is still high but real world testing will show the true numbers...
The 20-fold increase for TE012 as compared to the TM113 mode makes eminent sense:
1) As remarked by TheTraveller (http://forum.nasaspaceflight.com/index.php?topic=38203.msg1416603#msg1416603), Prof. Yang reported that her Finite Element Analysis showsQuoteThe thrust curves demonstrate that on the surfaces of the major and minor end plates the magnetic thrust (due to TE modes) is two orders of magnitude higher than the electric thrust (due to TM mode s)[quotes added by me for clarity, bold added for emphasis]
Two orders of magnitude means 100 times greater magnitude force for TE modes than for TM modes
(http://forum.nasaspaceflight.com/xindex.php,qaction=dlattach,3Btopic=38203.0,3Battach=1057003,3Bimage.pagespeed.ic.TVxGf41Rb-.webp)
2) As shown in the EM Drive Wiki ( http://emdrive.wiki/Experimental_Results)
The only experiment conducted by NASA Eagleworks using a TE mode (TE012 with a dielectric) resulted in
TE012 21 mN/kW
compared to
TM212 3 to 5 mN/KW
...Pouring quikrete into my anti-vibration platforms. The thin plastic wasn't good enough for me so I took them apart and laying down a foundation layer of concrete to stiffen them and add some weight, but still allow the rest of the antivibration system to work. They will need to sit on a leveled platform for at least 72 hours. Oh and I also measured and weighted each one. And each one will be sitting on 5 hockey pucks of sorbothane when they are done.
Shell
I am looking forward to the day when I can post
Engage!
I'm closer. Waiting for rfmwguy and Shell...I am looking forward to the day when I can post
Engage!
I would just like to be able to follow what people are saying. The forum's content really has surpassed my ability to understand what's going on.
Are we closer to knowing if there's something real here after all or not?
Re-setup of test stand begins tomorrow with some mods, oil bath dampener, beam support wires, counterweight attachment, laser pointer remount, mirror on tripod and tripod mounted target paper. Galinstan not yet arrived. Lots of minor stuff before test a week from tomorrow...plus house guests...I'm closer. Waiting for rfmwguy and Shell...I am looking forward to the day when I can post
Engage!
I would just like to be able to follow what people are saying. The forum's content really has surpassed my ability to understand what's going on.
Are we closer to knowing if there's something real here after all or not?
Question for folks here: do we know which result parameters from the Meep (or other simulation software) represent "goodness", predicting desirable performance? High Q? Big Pointng Vector? Or even some dynamic pattern?
I don't have the physics nor electrical engineering chops to have a clue what this all means, what's good, what's bad.
But I have some experience with some interesting technologies, including neural networks and genetic algorithms, that are really "artificial stupidity" emulators - Genetic algorithms, in particular, constitute wide scope search algorithms that are sometimes able to solve questions we don't know how to solve. They can be used to explore large search spaces, like the field of parameters governing the size, shape, material, frequency, power and relative humidity, if you like. Whatever you can crank into your evaluation function (which, for example, might be a Meep run).
If someone else can identify the range of interesting input parameters, and a way to compare outputs (this is better than that, for some reason you tell me, based on some output value) - well, then we could attempt to evolve solutions (even absent understanding of the empirical reason for changes in one way or another) using genetic mutation (random variation) and cross fertilization (sub-solution parameter exchange). The result of the mutation and cross fertilization would be run through tournament-style competitions against previously known models, seeking those changes than improve the output results.
I'm not in a position to help program control files to accomplish something (like testing 2 or 3 antennae, or their shape, or position) - but I could help to figure out how to drive an automated genetic algorithm driving Meep.
If there's interest, PM me.
I am looking forward to the day when I can postMe too. I've got a promise to uphold.
Engage!
Pretty neat stuff, used it before in the semi industry....Pouring quikrete into my anti-vibration platforms. The thin plastic wasn't good enough for me so I took them apart and laying down a foundation layer of concrete to stiffen them and add some weight, but still allow the rest of the antivibration system to work. They will need to sit on a leveled platform for at least 72 hours. Oh and I also measured and weighted each one. And each one will be sitting on 5 hockey pucks of sorbothane when they are done.
Shell
I had to look that up :)
Sorbothane is the tradename for a polyether-based polyurethane material with a huge damping material property:
tan delta = 0.5
Lots of engineering properties for Sorbothane here: http://www.lrcltd.co.uk/products/sorbothane_c.php
I know I know so little isty bittsy tiny details. I miss the days when I'd say make it so and watch a well oiled team go to work, well kinda. ;)Re-setup of test stand begins tomorrow with some mods, oil bath dampener, beam support wires, counterweight attachment, laser pointer remount, mirror on tripod and tripod mounted target paper. Galinstan not yet arrived. Lots of minor stuff before test a week from tomorrow...plus house guests...I'm closer. Waiting for rfmwguy and Shell...I am looking forward to the day when I can post
Engage!
I would just like to be able to follow what people are saying. The forum's content really has surpassed my ability to understand what's going on.
Are we closer to knowing if there's something real here after all or not?
I think you summed it up quite nicely imbfan and that's all we have. So many are wanting us to build a supersonic engine when we have barely got it to start and sometimes idle. We don't even know if it runs on swamp gas or foobiedust or a GE Microwave.Question for folks here: do we know which result parameters from the Meep (or other simulation software) represent "goodness", predicting desirable performance? High Q? Big Pointng Vector? Or even some dynamic pattern?
I don't have the physics nor electrical engineering chops to have a clue what this all means, what's good, what's bad.
But I have some experience with some interesting technologies, including neural networks and genetic algorithms, that are really "artificial stupidity" emulators - Genetic algorithms, in particular, constitute wide scope search algorithms that are sometimes able to solve questions we don't know how to solve. They can be used to explore large search spaces, like the field of parameters governing the size, shape, material, frequency, power and relative humidity, if you like. Whatever you can crank into your evaluation function (which, for example, might be a Meep run).
If someone else can identify the range of interesting input parameters, and a way to compare outputs (this is better than that, for some reason you tell me, based on some output value) - well, then we could attempt to evolve solutions (even absent understanding of the empirical reason for changes in one way or another) using genetic mutation (random variation) and cross fertilization (sub-solution parameter exchange). The result of the mutation and cross fertilization would be run through tournament-style competitions against previously known models, seeking those changes than improve the output results.
I'm not in a position to help program control files to accomplish something (like testing 2 or 3 antennae, or their shape, or position) - but I could help to figure out how to drive an automated genetic algorithm driving Meep.
If there's interest, PM me.
From what little I've been able to understand, the problem is experimental data. The analysis that has been done on previous experiments has been sketchy due to a severe lack of data. For instance, only one experiment has definitively verified mode shape via an infrared camera, and several experiments report one set of numbers for size and shape of the cavity but further analysis reveals problems with the numbers. Several razor sharp minds have come up with various theories, but none have been experimentally verified. There are theories that attenuation is good, and some where it is bad. Theories that call for a high Q, some suggestions that lower Q may be good coupled with something else.
Bottom line, no one quite knows - and has proven - what "good" is. Dr. Rodal's analysis reveals there are interesting asymmetries in stress tensors (I think that's what they were) - maximize asymmetry. TheTraveller's spreadsheet is modeled after Shawyer's proprietary program and has thrust as an output, so that may be fruitful as well - maximize thrust. There's another spreadsheet floating around as well that had McCulloch's and Notsosureofit's theories, I can't seem to find the author or link though. Just be aware that any optimizations may be blind alleys, because we just don't know. So, if you're itching and burning to optimize SOMETHING, then those avenues may be worthwhile. Spreadsheets would be the handiest to experiment on, Meep is simple to run but a bit more difficult to program unless you are familiar with Lisp (Guile/Scheme implementation) and Mathematica is a commercial program (expensive unless you have access at university or work).
All the above is my own interpretation, and is probably riddled with inaccuracies, but may be a nice jumping off point for you.
A clarification: rather than an asymmetry in the stress tensor, an asymmetry in the EM Drive: tapering from the big base to the small base. The stress tensor is symmetric at each point. The stresses and the forces on the big base are different from those on the small base.And so what of the side wall forces?
@Dr. Rodal,
You had such a dramatic change between the 32 and 64 cycle runs that I went ahead and uploaded the csv files for the 128 cycle run. png views will be later. It is the same model as before, Yang-Shell SE 2d dipole antenna. Note that I changed the naming convention slightly. I replaced the SE and BE (big and small end indicators) with the actual row numbers, z15, z214 - and z30 is included.
https://drive.google.com/folderview?id=0B1XizxEfB23tfk81T1VtcDhjYzEyWjV6MEtBel9Fd3VQalhRWXFGU3k2VUVfZ0c4LTZxeGc&usp=sharing (https://drive.google.com/folderview?id=0B1XizxEfB23tfk81T1VtcDhjYzEyWjV6MEtBel9Fd3VQalhRWXFGU3k2VUVfZ0c4LTZxeGc&usp=sharing)
aero
I think you summed it up quite nicely imbfan and that's all we have. So many are wanting us to build a supersonic engine when we have barely got it to start and sometimes idle. We don't even know if it runs on swamp gas or foobiedust or a GE Microwave.Question for folks here: do we know which result parameters from the Meep (or other simulation software) represent "goodness", predicting desirable performance? High Q? Big Pointng Vector? Or even some dynamic pattern?
I don't have the physics nor electrical engineering chops to have a clue what this all means, what's good, what's bad.
But I have some experience with some interesting technologies, including neural networks and genetic algorithms, that are really "artificial stupidity" emulators - Genetic algorithms, in particular, constitute wide scope search algorithms that are sometimes able to solve questions we don't know how to solve. They can be used to explore large search spaces, like the field of parameters governing the size, shape, material, frequency, power and relative humidity, if you like. Whatever you can crank into your evaluation function (which, for example, might be a Meep run).
If someone else can identify the range of interesting input parameters, and a way to compare outputs (this is better than that, for some reason you tell me, based on some output value) - well, then we could attempt to evolve solutions (even absent understanding of the empirical reason for changes in one way or another) using genetic mutation (random variation) and cross fertilization (sub-solution parameter exchange). The result of the mutation and cross fertilization would be run through tournament-style competitions against previously known models, seeking those changes than improve the output results.
I'm not in a position to help program control files to accomplish something (like testing 2 or 3 antennae, or their shape, or position) - but I could help to figure out how to drive an automated genetic algorithm driving Meep.
If there's interest, PM me.
From what little I've been able to understand, the problem is experimental data. The analysis that has been done on previous experiments has been sketchy due to a severe lack of data. For instance, only one experiment has definitively verified mode shape via an infrared camera, and several experiments report one set of numbers for size and shape of the cavity but further analysis reveals problems with the numbers. Several razor sharp minds have come up with various theories, but none have been experimentally verified. There are theories that attenuation is good, and some where it is bad. Theories that call for a high Q, some suggestions that lower Q may be good coupled with something else.
Bottom line, no one quite knows - and has proven - what "good" is. Dr. Rodal's analysis reveals there are interesting asymmetries in stress tensors (I think that's what they were) - maximize asymmetry. TheTraveller's spreadsheet is modeled after Shawyer's proprietary program and has thrust as an output, so that may be fruitful as well - maximize thrust. There's another spreadsheet floating around as well that had McCulloch's and Notsosureofit's theories, I can't seem to find the author or link though. Just be aware that any optimizations may be blind alleys, because we just don't know. So, if you're itching and burning to optimize SOMETHING, then those avenues may be worthwhile. Spreadsheets would be the handiest to experiment on, Meep is simple to run but a bit more difficult to program unless you are familiar with Lisp (Guile/Scheme implementation) and Mathematica is a commercial program (expensive unless you have access at university or work).
All the above is my own interpretation, and is probably riddled with inaccuracies, but may be a nice jumping off point for you.
You must admit it is a great puzzle and so many highly qualified people working on it posting clues they see or great ideas. I feel it's close, very close to see solid data. A theory? Maybe a little time longer. Could it be that's why things are so quiet out there? Someone has a great theory and is backing it up with closed door EMDrive testing data? Who knows what is hidden behind closed corporate and governmental doors? All I can say this little old lady is pushing hard to make it so and I'll be as open as the doors to an all you can eat diner.
I'm looking forward to the day I can say eureka woo hoo or I've another fancy bug zapper.
Shell
Think about them. That's why I think it is better to put the antenna RF feed near the big base.A clarification: rather than an asymmetry in the stress tensor, an asymmetry in the EM Drive: tapering from the big base to the small base. The stress tensor is symmetric at each point. The stresses and the forces on the big base are different from those on the small base.And so what of the side wall forces?
Think about them. That's why it is better to put the antenna RF feed near the big base.
QuoteThink about them. That's why it is better to put the antenna RF feed near the big base.
Because at least a portion of the pressure on the sidewalls amounts to 'thrust' in the forward direction? Because they are angled and not straight?
I keep thinking about these rapidly forming and decaying...shapes or modes...in the various nifty pictures. Seems almost like they provide a 'punch' in the right direction but decay so fast CoE doesn't have time to properly kick in. Which is flat out ridiculous.
I also keep thinking this forming/decaying real fast bit accounts for a hefty chunk of the out of whack experimental results: I suspect at some point the whole cycle will become so unstable it collapses and needs to be reset (but if so, how long a reset period?) More, the overall collapse is not uniform, so same experimental model, same conditions, inputs, and whatnot could collapse at different times.
(hm...maybe the best testers of this device would be twelve year old video game players? honed reflexes and all?)
Getting a handle on the thermal end of things might stave off the collapse for a while, but doesn't address the inherit underlying instability.
If it's mode stability that truly makes this thing work then it can be achieved in the wht waveguide using standard technologies and in the frustum.QuoteThink about them. That's why it is better to put the antenna RF feed near the big base.
Because at least a portion of the pressure on the sidewalls amounts to 'thrust' in the forward direction? Because they are angled and not straight?
I keep thinking about these rapidly forming and decaying...shapes or modes...in the various nifty pictures. Seems almost like they provide a 'punch' in the right direction but decay so fast CoE doesn't have time to properly kick in. Which is flat out ridiculous.
I also keep thinking this forming/decaying real fast bit accounts for a hefty chunk of the out of whack experimental results: I suspect at some point the whole cycle will become so unstable it collapses and needs to be reset (but if so, how long a reset period?) More, the overall collapse is not uniform, so same experimental model, same conditions, inputs, and whatnot could collapse at different times.
(hm...maybe the best testers of this device would be twelve year old video game players? honed reflexes and all?)
Getting a handle on the thermal end of things might stave off the collapse for a while, but doesn't address the inherit underlying instability.
Also you might want to think about how the decay of evanescent waves could impart the cycling stresses into the ends and walls while decaying. I wonder about this decaying wave function still.
QuoteThink about them. That's why it is better to put the antenna RF feed near the big base.
Because at least a portion of the pressure on the sidewalls amounts to 'thrust' in the forward direction? Because they are angled and not straight?
I keep thinking about these rapidly forming and decaying...shapes or modes...in the various nifty pictures. Seems almost like they provide a 'punch' in the right direction but decay so fast CoE doesn't have time to properly kick in. Which is flat out ridiculous.
I also keep thinking this forming/decaying real fast bit accounts for a hefty chunk of the out of whack experimental results: I suspect at some point the whole cycle will become so unstable it collapses and needs to be reset (but if so, how long a reset period?) More, the overall collapse is not uniform, so same experimental model, same conditions, inputs, and whatnot could collapse at different times.
(hm...maybe the best testers of this device would be twelve year old video game players? honed reflexes and all?)
Getting a handle on the thermal end of things might stave off the collapse for a while, but doesn't address the inherit underlying instability.
Wow, even with mode collapsing we're kicking up the force factor?@Dr. Rodal,
You had such a dramatic change between the 32 and 64 cycle runs that I went ahead and uploaded the csv files for the 128 cycle run. png views will be later. It is the same model as before, Yang-Shell SE 2d dipole antenna. Note that I changed the naming convention slightly. I replaced the SE and BE (big and small end indicators) with the actual row numbers, z15, z214 - and z30 is included.
https://drive.google.com/folderview?id=0B1XizxEfB23tfk81T1VtcDhjYzEyWjV6MEtBel9Fd3VQalhRWXFGU3k2VUVfZ0c4LTZxeGc&usp=sharing (https://drive.google.com/folderview?id=0B1XizxEfB23tfk81T1VtcDhjYzEyWjV6MEtBel9Fd3VQalhRWXFGU3k2VUVfZ0c4LTZxeGc&usp=sharing)
aero
That made the force grow by a factor of 6,800 times the force differential between the bases for 64 cycles. The net force difference between the bases is 0.2 microNewtons for 800 watts at this point.
QuoteThink about them. That's why it is better to put the antenna RF feed near the big base.
If the collapse takes place at multiples of 187.5 and can maintain energy by shifting to a higher frequency I'm going to go hide in a cave for a bit.
If it's mode stability that truly makes this thing work then it can be achieved in the wht waveguide using standard technologies and in the frustum.
http://journals.aps.org/prstab/pdf/10.1103/PhysRevSTAB.13.022004
Right now we simply don't know if it's the ordered instability of the mode switching creating hammering stress tensors into the ends or walls or what but it's going to be an interesting ride to find out.
Also you might want to think about how the decay of evanescent waves could impart the cycling stresses into the ends and walls while decaying. I wonder about this decaying wave function still.
DeltaMass at reply 669 reminds me of something that's been bugging me for a few days now.
If I recall correctly, Dr. Rodal is calculating net forces on the end plates, due to the complexity of the sidewall calculations. If that's a mistaken impression, let me know and I can stop worrying.
If that's right though, net force on the ends tells us very little. If we had a frustum shaped balloon, there would be net air pressure towards the big end on that calculation. Further, one of the criticisms of Shawyers explanation was that he had mis-handled the contribution from the side walls which should have made the net calculated force zero.
Bottom line is that we need sidewall forces to draw any conclusions at all on total force.
Please don't anyone jump to the conclusion that I'm in any way belittling what's been done with MEEP and post-processing - I think it's a fantastic effort, and looks to be close to being able to answer the central question of force generation. But it does need that last step to be taken.
***************************************
If it's mode stability that truly makes this thing work then it can be achieved in the wht waveguide using standard technologies and in the frustum.
http://journals.aps.org/prstab/pdf/10.1103/PhysRevSTAB.13.022004
Right now we simply don't know if it's the ordered instability of the mode switching creating hammering stress tensors into the ends or walls or what but it's going to be an interesting ride to find out.
Also you might want to think about how the decay of evanescent waves could impart the cycling stresses into the ends and walls while decaying. I wonder about this decaying wave function still.
Shell,
Q: is there any experimental setup you can think of that would help to understand if the forces originate from hammering the end plates or whether they come to life through evanescent waves along the sidewalls?
*****
A: I'm thinking if it is evanescent waves I should see a ratio as you increase the distance of the small plate within the cavity and have been researching. (interesting read) http://spie.org/x16896.xml
One reason I wanted the gold electroplating to be around 5um on the small plate to allow evanescent wave tunneling using schrodinger's equations.
*****
Q: How the experiment(s) could be modified to support/disapprove the several theories is most likely the next phase, once the initial tests do provide a significant force signal.
*****
A: And I'll welcome all inputs.
*****
On a side note:
Q: Because the waveguide openings in the sidewalls seriously disrupt the wave patterns, I'm wondering if there exist a microwave equivalent of what the spy mirror glass is for visual light.
Are there materials that are more microwave reflective on one side then the other, effectively allowing them to pass from one side, but not from the other?
Such a material would solve the large cuts in the sidewalls (and their disruptive influence on the resonance patterns), and allow the wave guide to be fed through the large bottom plate...
******
A: I've not researched that yet to any extreme. On my bucket list. ;) I think inserting the wave forms symmetrically opposed into the cavity is so much better than Tajmar & Fiedler's single magnetron angled approach. ... Shell
**Op-Ed: EMDrive ‘does work’, but Spectator Science disagrees**
http://www.digitaljournal.com/science/op-ed-emdrive-does-work-but-spectator-science-disagrees/article/441374
Must send him a link to the "E Files":
https://drive.google.com/folderview?id=0B7kgKijo-p0ifnFrZ2V1UmZEY25FXzNrX0hjNXJmQXR5YzRnaVBqcTdMZUhxcjVkMUUtaXc&usp=sharing
It is way, way too early to start jumping to conclusions. Anyone who does is not being fair. Until open and replicated experimental data is available, it's all noise as far as I'm concerned. As matters stand, there is nothing that is open and replicated.Why are we here? Perchance to dream.
The ironclad test is a space test. This cannot readily be fooled with artifacts. What's required for that is twin units in reasonably close proximity, one powered and one not, and in all other respects identical.
Hydrogen sulfide — the compound responsible for the smell of rotten eggs — conducts electricity with zero resistance at a record high temperature of 203 kelvin (–70 °C), reports a paper published today in Nature.
Dr. Rodal -Concerning DeltaMass, he has asked questions such as: what system can self-accelerate in space and be consistent with General Relativity and conservation of momentum and conservation of energy? So, deltaMass is not adverse to using the Socratic method.
Gosh, this might be quite fun!
Since you've shown meep runs with compressive force at one end and tensile force at the other, I think it is far from obvious what the answer is. Yes, if the fields are axially symmetric, one could deduce that the force on the sidewalls is purely axial, but that doesn't help much, and in any case other meep runs on the end faces have shown a lack of such symmetry likely to be extended to the side walls by continuity.
Dearie me I feel such a silly! Perhaps you could enlighten me (and perhaps DeltaMass, who didn't know the answer five minutes ago, though I'm sure he's clever enough to figure it out for himself!) - I'm sure that actually it might be a little quicker to simply articulate the argument, rather than ask so many question which I confess I find rather dazzlingly brilliant!
R.
Continuing from http://forum.nasaspaceflight.com/index.php?topic=38203.msg1416443#msg1416443
we present the forces at the small and the big base for Yang/Shell 6 degree truncated cone excited in mode TE012 at 2.45 GHz with a parallel 2 dipole antenna located near the small end, for 3 times after turning the RF feed on: 0.013 microseconds, 0.026 microseconds, and 0.052 microseconds. These are results from Meep runs by aero, that have been post-processed using a code I wrote using Wolfram Mathematica.
Notice that the rate of growth per unit time is diminishing with time:
Time Normalized Force/Time Linear Slope Exponential Force
(μsec) magnification (10^(-12) Newton/43 watt)
0.013 (-0.000094878)/(-0.00365708) t = 0.02594 t 0.0220981 t -0.00365708
0.026 (-0.040004)/( -1.99742) t = 0.02003 t 0.0177789 t -1.99742
0.052 (-102.715)/(-10496.2) t = 0.00979 t 0.00992341 t -10496.2
At this rate, the force differential will be in the milliNewton range for 800 watts after approximately 0.1 to 0.5 μsec after the RF feed is turned on.
QuoteThink about them. That's why it is better to put the antenna RF feed near the big base.
If the collapse takes place at multiples of 187.5 and can maintain energy by shifting to a higher frequency I'm going to go hide in a cave for a bit.
I had to burst out laughing, I read and remember way too much. lol
http://www.forbes.com/sites/paulrodgers/2015/04/02/message-from-the-aliens-187-5/
Been a long day... thanks for the smile.
Shell
Continuing from http://forum.nasaspaceflight.com/index.php?topic=38203.msg1416443#msg1416443
we present the forces at the small and the big base for Yang/Shell 6 degree truncated cone excited in mode TE012 at 2.45 GHz with a parallel 2 dipole antenna located near the small end, for 3 times after turning the RF feed on: 0.013 microseconds, 0.026 microseconds, and 0.052 microseconds. These are results from Meep runs by aero, that have been post-processed using a code I wrote using Wolfram Mathematica.
Notice that the rate of growth per unit time is diminishing with time:
Time Normalized Force/Time Linear Slope Exponential Force
(μsec) magnification (10^(-12) Newton/43 watt)
0.013 (-0.000094878)/(-0.00365708) t = 0.02594 t 0.0220981 t -0.00365708
0.026 (-0.040004)/( -1.99742) t = 0.02003 t 0.0177789 t -1.99742
0.052 (-102.715)/(-10496.2) t = 0.00979 t 0.00992341 t -10496.2
At this rate, the force differential will be in the milliNewton range for 800 watts after approximately 0.1 to 0.5 μsec after the RF feed is turned on.
So it's creating thrust in pulses that are longer than the meep run? I wonder if the turn on effect might indicate that it takes a certain number of pulses for the system to stabilize at max thrust.
I have modelled the Yang-Shell frustum with the antenna located near the big end. I have made 3 meep runs, one each for 32, 64 and 128 complete cycles with the final 14 time slices saved, a slice each one-tenth cycle. I have generated and uploaded the csv file data sets for Dr. Rodal's attention.
First, the 32 cycle run here:
https://drive.google.com/folderview?id=0B1XizxEfB23tfmFENmwzYzZ5aTNVaW5sWC1YYVl5Qm4yQ3J5SmhtTkVnYUxXYUJMZzZVa1E&usp=sharing (https://drive.google.com/folderview?id=0B1XizxEfB23tfmFENmwzYzZ5aTNVaW5sWC1YYVl5Qm4yQ3J5SmhtTkVnYUxXYUJMZzZVa1E&usp=sharing)
Second, the 64 cycle run here:
https://drive.google.com/folderview?id=0B1XizxEfB23tfmlwOWVvbVB1aHA0NkMtQ0dtUjFuZks2NzZ2MGxXdWhkUTEyWWNxd2hPalE&usp=sharing (https://drive.google.com/folderview?id=0B1XizxEfB23tfmlwOWVvbVB1aHA0NkMtQ0dtUjFuZks2NzZ2MGxXdWhkUTEyWWNxd2hPalE&usp=sharing)
And lastly, the 128 cycle run here:
https://drive.google.com/folderview?id=0B1XizxEfB23tfmRvWXRHM0xWMGRpWU84RlNwQktDR3dqZWpfVDBhbEhDR2RwMEJYMERDVEE&usp=sharing (https://drive.google.com/folderview?id=0B1XizxEfB23tfmRvWXRHM0xWMGRpWU84RlNwQktDR3dqZWpfVDBhbEhDR2RwMEJYMERDVEE&usp=sharing)
My apologises to SeeShells, as the png-view files are not yet available. We are working on it. I note that the Quality factor calculated by Harminv for this antenna configuration puts it well into the superconducting cavity arena. I am anxious to see the png views myself because if my thought that evanescent waves actually accomplish their superluminal behaviour via a form of tunnelling, then with this high Q model, there should be enough energy stored within the cavity to trigger tunnelling through the bases. And preferentially through the base where the EM waves are more energetic. But meep likely wouldn't calculate anything like tunneling and there doesn't seem to be any indication in the csv files.
Note to Dr. Rodal - The Google drive upload process was a little wonky on the 32 and 64 cycle data. I think the data is ok, but if there are missing files don't be surprised but do let me know.
aero
I have modelled the Yang-Shell frustum with the antenna located near the big end. I have made 3 meep runs, one each for 32, 64 and 128 complete cycles with the final 14 time slices saved, a slice each one-tenth cycle. I have generated and uploaded the csv file data sets for Dr. Rodal's attention.
First, the 32 cycle run here:
https://drive.google.com/folderview?id=0B1XizxEfB23tfmFENmwzYzZ5aTNVaW5sWC1YYVl5Qm4yQ3J5SmhtTkVnYUxXYUJMZzZVa1E&usp=sharing (https://drive.google.com/folderview?id=0B1XizxEfB23tfmFENmwzYzZ5aTNVaW5sWC1YYVl5Qm4yQ3J5SmhtTkVnYUxXYUJMZzZVa1E&usp=sharing)
...
Note to Dr. Rodal - The Google drive upload process was a little wonky on the 32 and 64 cycle data. I think the data is ok, but if there are missing files don't be surprised but do let me know.
aero
I have modelled the Yang-Shell frustum with the antenna located near the big end. I have made 3 meep runs, one each for 32, 64 and 128 complete cycles with the final 14 time slices saved, a slice each one-tenth cycle. I have generated and uploaded the csv file data sets for Dr. Rodal's attention.
First, the 32 cycle run here:
https://drive.google.com/folderview?id=0B1XizxEfB23tfmFENmwzYzZ5aTNVaW5sWC1YYVl5Qm4yQ3J5SmhtTkVnYUxXYUJMZzZVa1E&usp=sharing (https://drive.google.com/folderview?id=0B1XizxEfB23tfmFENmwzYzZ5aTNVaW5sWC1YYVl5Qm4yQ3J5SmhtTkVnYUxXYUJMZzZVa1E&usp=sharing)
...
Note to Dr. Rodal - The Google drive upload process was a little wonky on the 32 and 64 cycle data. I think the data is ok, but if there are missing files don't be surprised but do let me know.
aero
Good to see (and to know) that the silver plating solved some of the layering/pitting issues that usually come with 3Dprinting...I presume that small cavity was cast using 3D printed model in wax, next the plaster mold was created, then molten Sterling silver was poured into the mold and finally - polished.
Everything is the same. I also checked the Poynting vector plots, the stress plots, and the force plots. All identical to the antenna near the small base. I also have plots of the fields in other directions showing the antenna is at the small base.
Well that sucks.As we say out West... Yeeiup.
It is way, way too early to start jumping to conclusions. Anyone who does is not being fair. Until open and replicated experimental data is available, it's all noise as far as I'm concerned. As matters stand, there is nothing that is open and replicated.
The ironclad test is a space test. This cannot readily be fooled with artifacts. What's required for that is twin units in reasonably close proximity, one powered and one not, and in all other respects identical.
The new version of the baby-EmDrive, 3D-printed and silver-plated has been received by the folks at hackaday.io (https://hackaday.io/project/5596-em-drive/log/23696-silver-cavity-arrived)!
Db = 29.64 mm
Ds = 16.12 mm
L = 21.87mm
+ cylindrical neck for tuning = 5mm
Antenna placement near the small base = 5.5 mm below cylindrical neck
Excitation frequency between 24 an 25 GHz.
Several modes predicted and very close from each others (TE013, TE114 and TM113) according to TT's spreadsheet.
Flat ends plates to begin with, but spherical ends are doable too.
(https://cdn.hackaday.io/images/880731439909923274.jpg) (https://hackaday.io/project/5596-em-drive/log/23696-silver-cavity-arrived)
The reason why Meep is an open source code is for users to write their own code to introduce whatever equations they want to use for the walls, etc. Many papers I have seen where Meep is used, it is not used as a black box but the researchers write the new parts of the code necessary for their research. Similarly, Wolfram Mathematica out of the box cannot post-process Meep data to calculate the Poynting vector, stress tensor, etc. I had to write code in Wolfram Mathematica to be able to ouput the stress, I had to write code to make the vector plots, etc..Well that sucks....From what I understand meep stops at the surface boundary of the walls with Maxwell. A Senior Physics student majoring in high energy physics mentioned it to me about the limits of meep, never verified it though, although it makes sense. ...
Stand corrected so I'll make it so... "out of the box, Meep..."The reason why Meep is an open source code is for users to write their own code to introduce whatever equations they want to use for the walls, etc. Many papers I have seen where Meep is used, it is not used as a black box but the researchers write the new parts of the code necessary for their research. Similarly, Wolfram Mathematica out of the box cannot post-process Meep data to calculate the Poynting vector, stress tensor, etc. I had to write code in Wolfram Mathematica to be able to ouput the stress, I had to write code to make the vector plots, etc..Well that sucks....From what I understand meep stops at the surface boundary of the walls with Maxwell. A Senior Physics student majoring in high energy physics mentioned it to me about the limits of meep, never verified it though, although it makes sense. ...
Therefore open codes that enable the user to write their own code do not have limitations, as anything that can be analyzed certainly can be coded (as proved by von Neumann). If there is an equation that expresses quantum tunneling as a function of the wall thickness, material, and the surrounding electromagnetic fields, that equation can in principle be coded into Meep (or into Wolfram Mathematica, or into C). At that point, the question is rather what code is more expedient to program. Rather the statement has to be qualified to read instead "out of the box, Meep..."
Here is an EM Drive test that we can all do in a bathtub (no, a hot tub is not required) without having to worry about dangerous magnetrons, or getting electrocuted.That's most unscientific. The intrinsic x-y momentum of the driving source is not examined and not controlled for. The least one could do to be honest here is to flip the shape around so that now the small end faces right.
EM Drive 2D simulation by Grzegorz Maj using water as a medium (not the first time that a physics problems with waves has been analyzed using water as an analog) "the Water Drive"
Droplets falling on the Water Drive are used to create waves inside the Water Drive.
Notice that it moves towards the big base.
https://www.youtube.com/watch?t=77&v=VEacNk2uFaM
Suggestion: try other shapes (squares, circles, trombone, etc.).
I'm surprised that you think the protocol I described is that flawed. Obviously, as well, you'd want to repeat the experiment with the other one powered and the original (powered) one now unpowered.It is way, way too early to start jumping to conclusions. Anyone who does is not being fair. Until open and replicated experimental data is available, it's all noise as far as I'm concerned. As matters stand, there is nothing that is open and replicated.
The ironclad test is a space test. This cannot readily be fooled with artifacts. What's required for that is twin units in reasonably close proximity, one powered and one not, and in all other respects identical.
I know I'm a broken record, but IMHO there are many more uncontrollable favors in low earth orbit than in the lab, considering the minscule power available for the thruster on a cubesat.
Ok...latest thing I have been wondering (as per earlier conversation with Doctor Rodal)
Would an 'electromagnetic Dean Drive' actually move itself (and attached spacecraft) in space? Aka high earth orbit or interplanetary space. (Because 'electromagnetic Dean Drive' is what Rodal has mentioned more than once.)
The reduced thrust in a vacuum bothers me here. As Shell says, giant red flag. Also wonder how much of a vacuum for these tests as compared with very high orbit or interplanetary space.
Another red flag is Shawyer electing to focus on EM Drive uses for within an atmosphere. From a straightforward engineering perspective, he knows the capabilities of these devices better than anybody - maybe. He must have a great deal of unreleased test data.
Starting to suspect that a fully depressurized EM Drive in high orbit/interplanetary space would either
1) not move the spacecraft; OR
2) have a performance comparable to a photon rocket. Best case might be thrust a few dozen times that of a photon rocket for unclear reasons.
Still wondering if a pressurized EM Drive in high orbit / interplanetary space would produce thrust comparable to tests in atmosphere. Question becomes - pressurized with what?
...
On the top of my rotary table but under all the equipment will be a thin copper layer that will serve as my reference ground plane. Everything will be grounded to this high frequency ground reference plane.
...
Anybody who has ever designed and debugged a high frequency pcb knows the value of a solid copper ground plane.
So yes ground loops can be a problem but not if using a large area solid copper ground plane with additional high frequency decoupling capacitors and ferrite donuts.
At 2.4 GHz ferrite donuts are not needed. Instead an air core inductor inline with each power lead that is not at ground potential is all that is needed. Filter caps on either side of the inductor are used to prevent voltage sag from current transients. They are a high impedance path to RF. But since the inductor only needs to be a few nH. caps are not needed.
The fustrum is your ground plane. No thin copper sheet is needed. Any conductors going to this ersatz ground plane will be many wavelengths long. So it is impossible to make this copper sheet a ground at RF.
The biggest problem with driving a fustrum from a coax feed is matching the loop inside the cavity. It is virtually impossible to make the loop exactly the right length so it will almost never be a 50 Ohms resistive load at the frequency used. It will always be capacitive because of the adjacent cavity walls. So a large part of the RF sent into the cavity will just get reflected back on the shield. Ferrites are only useful up to VHF frequencies so putting ferrite donuts on the coax will have no effect. Maybe coiling the coax will help but a lot of RF will still get radiated because of the mismatch. Matching networks can be used but in that case the return wave is just dissipated in the matching network.
Quite right - there is a very significant difference between power grounding and RF grounding. At the appoximately 12cm wavelengths most folks are working with (2.45 Ghz or thereabout) any ground lead longer than about 6cm is also a pretty decent radiator. Google RF grounding - there is wealth of info about it. Power and safety ground are also very important.
Just a comment from those using loop antennas. Loop antennas are magnetic antenna and work differently from antennas like dipoles and monopoles. The common circumference for loop antennas is on the order of 1 lambda not lambda/2. A half wavelength circmumference will have a VERY high input impedance and will be hard to couple. A full wavelength loop will be significantly closer to 50 ohms, although wavelength variations due to excited mode and geometry of the cavity will also have significant effects. I will try to model up some example loops and patterns later today/tonight when I have access to the software.
Herman
I thought a 1/10 wave loop or even a simulating square loop would work well and aero and imbfan have tried to model it in meep, although it's a very tough nut to crack in the meep software.
I would love to see your models.
Shell
Good Questions.Sorry this has taken so long to get results on modeling. Family responsibilities keep interrupting important EMDRIVE work ;). Anyway I modeled several loops - all using #18gauge (very close to 1mm) copper wire, located 1/2 wavelength above "perfect" ground. All driven at 2450 Mhz. Models are all based on 24 element, 7segments per element, fed at point closest to ground plane.
Shell - I haven't gotten the tenth wavelength model working yet - keep getting geometry errors from NEC. Still working and will report as soon as possible. lambda/10 and smaller loops are 'different' - very sharp tuning and critical. Often losses in the loop material swamp the radiation resistance.
Anyway - here are the input impedances for the various cases.
one lambda loop : Z = 96.9 - j91.5 ohms
half lambda loop : Z = 553 - j87.6 ohms
two lambda loop : Z = 200 - j38 ohms
I will post far field patterns this evening. Have to go to that darn work stuff.
Herman
May I ask:
1) why you used 1/2 wavelength above the ground plane and not 1/4 wave?
2) are these loop models parallel to the ground plane (same 1/2 wave spacing to the ground plane at all points of loop circumference) or orthogonal to it?
3) lambda at 2.45GHz is 122.33mm, so a 2 lambda loop is 244.67mm in circumference and 77.9mm in diameter?
Thanks so much for the information. Most appreciated.
NSF-1701 update...all is now complete and the unit is mounted on the balance beam including oil dampener plus electrodes/cups waiting for galinstan! I't try and do a video walkound of the completed test stand tonight. Once the galinstan arrives, I'll do the test. Still have to attach laser and set up mirrors and target, but for all intents and purposes...its ready to go! Wish me luck. 8)
NSF-1701 update...all is now complete and the unit is mounted on the balance beam including oil dampener plus electrodes/cups waiting for galinstan! I't try and do a video walkound of the completed test stand tonight. Once the galinstan arrives, I'll do the test. Still have to attach laser and set up mirrors and target, but for all intents and purposes...its ready to go! Wish me luck. 8)
I'm surprised that you think the protocol I described is that flawed. Obviously, as well, you'd want to repeat the experiment with the other one powered and the original (powered) one now unpowered.It is way, way too early to start jumping to conclusions. Anyone who does is not being fair. Until open and replicated experimental data is available, it's all noise as far as I'm concerned. As matters stand, there is nothing that is open and replicated.
The ironclad test is a space test. This cannot readily be fooled with artifacts. What's required for that is twin units in reasonably close proximity, one powered and one not, and in all other respects identical.
I know I'm a broken record, but IMHO there are many more uncontrollable favors in low earth orbit than in the lab, considering the minscule power available for the thruster on a cubesat.
I really liked this recent article on the EmDrive. Not always spoke about the Emdrive itself, but about something Mr. rfmwguy described as "chruch science" and keeping to old ways.
One can also describe it as a critic of the critique.
http://www.digitaljournal.com/science/op-ed-emdrive-does-work-but-spectator-science-disagrees/article/441374
Guys, check this out.As a physics-educated engineer, it is difficult to experience empathy and humility when confronted with this cacophony of ignorance displayed in both the article and the comments. It is akin to watching apes jumping and screaming at one another at the zoo. So sad.
http://hackaday.com/2015/08/19/the-em-drive-might-not-work-but-we-get-helicarriers-if-it-does/
Lots of comments ...
Guys, check this out.As a physics-educated engineer, it is difficult to experience empathy and humility when confronted with this cacophony of ignorance displayed in both the article and the comments. It is akin to watching apes jumping and screaming at one another at the zoo. So sad.
http://hackaday.com/2015/08/19/the-em-drive-might-not-work-but-we-get-helicarriers-if-it-does/
Lots of comments ...
Thanks for the reference(s) TT.
I could see no suggestion in the Yang paper sections you pointed to indicating that the forces on the side walls net to zero. The Shawyer ppt you just referenced just says that the side wall forces are less than those on the big end. There is no support for the implicit suggestion elsewhere here that side wall forces don't need to be calculated, or perhaps can be derived simply from the end wall forces.
R.
Cavities with spherical end plates are different to cavities with flat end plates. With spherical end plates, set to be the radius they are from the frustum vertex, the propagated EM waves are spherical and as such the waves at the side walls are orthogonal and generate no momentum transfer on the side walls as the cosine loss angle is at max. See attached.
With flat end plates, the propagating EM waves are a dog's breakfast, as the flat end plate reflections / bounces introduce very significant phase distortion into the reflected wave and reflection not back to the vertex (as with spherical end plates) but to the side walls.
So with flat end plates, there is need to factor in side wall Forces but not required if using spherical end plates set to their radius from the frustum vertex.
Shawyer's Force equation
F = (2 P Df Q) / c
does not take the difference between spherical end plates and flat end plates into consideration as I believe it was formulated before spherical end plates were considered.
The Traveller; question regarding the dynamics of the EM-Drive operation.
Per Shawyer "Second generation EMDrive propulsion applied to SSTO launcher and intersteller probe" (2015) Figure 6 he shows that after application of Power it takes something like 40 milliseconds to reach max thrust. If we are talking conservation of momentum should this not be happening in microseconds (the speed of light)? Is this the cycle build up that Dr Rodal was discussing? Or is this a function of how long he expects the magnetron phase lock relay / system to power up after application of power?
That drawing is in reference to using 8 cavities and cycling the Rf power pulses between them, with each pulse lasting 20% of 1 cavity time constant. I believe the reason may be to reduce cavity heating.
https://www.youtube.com/watch?v=wstIBq2H0z8Guys, check this out.As a physics-educated engineer, it is difficult to experience empathy and humility when confronted with this cacophony of ignorance displayed in both the article and the comments. It is akin to watching apes jumping and screaming at one another at the zoo. So sad.
http://hackaday.com/2015/08/19/the-em-drive-might-not-work-but-we-get-helicarriers-if-it-does/
Lots of comments ...
Every now and again I look at https://www.google.com/trends/explore#q=emdrive and I suspect there will be many more such articles and comment threads this year...Guys, check this out.As a physics-educated engineer, it is difficult to experience empathy and humility when confronted with this cacophony of ignorance displayed in both the article and the comments. It is akin to watching apes jumping and screaming at one another at the zoo. So sad.
http://hackaday.com/2015/08/19/the-em-drive-might-not-work-but-we-get-helicarriers-if-it-does/
Lots of comments ...
... Poland ...?https://www.youtube.com/watch?v=cSsTWRt0VBA
Well - It will be awhile yet for the longer runs. My stupid computer ran out of disk space so of course meep bombed on the file write. Luckily it was only the 64 cycle run, not the 128 cycles, so it only wasted half the time that it could have.
... Poland ...?....
posted by Maciej Ma?
I'm not entirely certain that google trends has got that right about Poland. I didn't notice any extrodinary evidence in his video.
Well - It will be awhile yet for the longer runs. My stupid computer ran out of disk space so of course meep bombed on the file write. Luckily it was only the 64 cycle run, not the 128 cycles, so it only wasted half the time that it could have.
Ds = 6,25NSF-1701 update...all is now complete and the unit is mounted on the balance beam including oil dampener plus electrodes/cups waiting for galinstan! I't try and do a video walkound of the completed test stand tonight. Once the galinstan arrives, I'll do the test. Still have to attach laser and set up mirrors and target, but for all intents and purposes...its ready to go! Wish me luck. 8)
If you have the time would you please measure your as built frustum dimensions and post so I can do a bit of work with my higher resolution spreadsheet.
Have you used a spectrum analyser to measure the freq spread and energy distribution of your magnetron under the load of the frustum? If not, if possible, please do so as that data may help to get a good idea of how much of the magnetron's output power spectrum will be able to form resonance and then to generate Force.
The idea is to try to avoid as much as possible what Prof Yang ran into where her frustum input bandwidth (tiny rectangle lower left in all the images) was very much out of alignment with the power output spectrum of the magnetron.
Long time Engineering lurker here with a simple question:There seems to be at the moment an implicit working assumption that EM field resonance is necessary for thrust. The primary use of MEEP here seems to be determining whether resonance is possible (and in what modes) for a given build configuration.. with a secondary use of investigating a number of other possible anomalous effects that might result from the application of our current theories of electromagnetism, etc (effects such as exponentially increasing Poynting vectors, evanescent waves, and many other things that I don't personally understand).
What exactly are you looking for in the MEEP simulations? What defines a good EMDrive field if we don't know what is causing thrust? My thought is that if the "ideal" situation is known, why not write a genetic algorithm to optimize the chamber shape and antenna placement (or at least find some local maxima). Sure it would likely cost some EC2 compute time and money, but isn't that cheaper than iterating with actual hardware?
Thanks everyone. Really enjoying your work.
All the best!
David
[Edit] And I'd like to add, as another long time lurker: I think you're doing yourself a disservice by not going back and actually reading all of the previous posts, from all 4 threads. I think you wouldn't have had to ask this question if you had gone back and REALLY caught up on this discussion from the beginning.
Yes nice paper. :)And no, they measured Q not Q_0, its not possible to measure Q_0 directly, one have to derive/calculate that from the complex measurement data.
The attached paper is pure GOLD. Going split screen with a Google translate, the German document is Ok to read and understand. If you are building a EMDrive, you really need to understand this paper like the back of your hand. Thanks so much X-Ray for sharing and making in public.
I now understand how the antenna coupling factor can make or break the actual operational Q and how if the coupling factor is bad may phase distort the excited mode into another false quasi mode and false quasi resonance.
Because of this paper my antenna design has completely changed. I now understand why Roger Shawyer suggested I explore using TE013. Nice breadcrumb there Roger. Thanks.
From one bread crumb to another, attached is my antenna coupling factor = 1 design and where it may be placed to fully ensure TE013 excitement and fully couple to the resonant EM waves. Will be supported on 3 threaded quartz rods with will allow the loop's orientation to be adjustment to get it just right. BTW thanks SeaShells for the quartz rod idea.
Next issue is to design a loop of the correct diameter and impedance. GrayBeardSysEng can you assist?
Once the loop antenna design is established, then need to come up with a new frustum design that will put the loop diameter in the centre of the centre TE013 H field lobe.
Easy peasy right?
Once the loop antenna design is established, then need to come up with a new frustum design that will put the loop diameter in the centre of the centre TE013 H field lobe.
Thanks for the reference(s) TT.
I could see no suggestion in the Yang paper sections you pointed to indicating that the forces on the side walls net to zero. The Shawyer ppt you just referenced just says that the side wall forces are less than those on the big end. There is no support for the implicit suggestion elsewhere here that side wall forces don't need to be calculated, or perhaps can be derived simply from the end wall forces.
R.
Cavities with spherical end plates are different to cavities with flat end plates. With spherical end plates, set to be the radius they are from the frustum vertex, the propagated EM waves are spherical and as such the waves at the side walls are orthogonal and generate no momentum transfer on the side walls as the cosine loss angle is at max. See attached.
With flat end plates, the propagating EM waves are a dog's breakfast, as the flat end plate reflections / bounces introduce very significant phase distortion into the reflected wave and reflection not back to the vertex (as with spherical end plates) but to the side walls.
So with flat end plates, there is need to factor in side wall Forces but not required if using spherical end plates set to their radius from the frustum vertex.
Shawyer's Force equation
F = (2 P Df Q) / c
does not take the difference between spherical end plates and flat end plates into consideration as I believe it was formulated before spherical end plates were considered.
Even with this simplified assumption of EM wave action and no force on the side walls, the force on each endplate would be the same. The size of the endplates are the same in steradians, and same EM power over the same area in steradians would cancel out perfectly.
With that drawing he has disproved his own proposal.
Shawyer clearly says the Force generated is not due to the static end plate momentum as in that situation the EMDrive is in IDLE mode:
</lurk>Did you ever find out what was causing the microwave detector to be set off on the small end?
Today I was thinking about the Yang design that used the 3 port circulator to feed the cavity and a dummy load to absorb the reflected radiation.
That dummy load could be replaced with a rectenna to lower the heat load/cooling requirements.
I also read "Microwave Radiation Force on a Parallel-Plate Resonator" by Sergey N. Makarov et al. That was interesting.
http://digitalcommons.wpi.edu/cgi/viewcontent.cgi?article=1013&context=electricalcomputerengineering-pubs
<lurk>
ABC News Australia: http://www.abc.net.au/news/2015-08-17/warp-speed-a-possibility-astrophysicist-says/6702034
"Long considered a staple of science fiction, high speed space travel between galaxies — or warp speed — may actually be possible, according to astrophysicist Professor Geraint Lewis.
Professor Lewis, from the University of Sydney, is set to deliver a talk today at the National Science Week in Sydney, and said the futuristic concept was actually part of Albert Einstein's theory of relativity."
Thanks Doc. Looks like 3 year old info just now making some (very) public rounds. ABC and Drudge just picked up on it. Funny how things linger; then years later come to life. Guess I am so used to instant info, like our NSF pal blogged from the AIAA conference. Guerrilla science reporting... ;)ABC News Australia: http://www.abc.net.au/news/2015-08-17/warp-speed-a-possibility-astrophysicist-says/6702034
"Long considered a staple of science fiction, high speed space travel between galaxies — or warp speed — may actually be possible, according to astrophysicist Professor Geraint Lewis.
Professor Lewis, from the University of Sydney, is set to deliver a talk today at the National Science Week in Sydney, and said the futuristic concept was actually part of Albert Einstein's theory of relativity."
Same Australian that wrote about the interaction of matter during acceleration and deceleration of an Alcubierre Drive:
http://arxiv.org/abs/1202.5708
Did you ever find out what was causing the microwave detector to be set off on the small end?
Yes nice paper. :)And no, they measured Q not Q_0, its not possible to measure Q_0 directly, one have to derive/calculate that from the complex measurement data.
The attached paper is pure GOLD. Going split screen with a Google translate, the German document is Ok to read and understand. If you are building a EMDrive, you really need to understand this paper like the back of your hand. Thanks so much X-Ray for sharing and making in public.
I now understand how the antenna coupling factor can make or break the actual operational Q and how if the coupling factor is bad may phase distort the excited mode into another false quasi mode and false quasi resonance.
Because of this paper my antenna design has completely changed. I now understand why Roger Shawyer suggested I explore using TE013. Nice breadcrumb there Roger. Thanks.
From one bread crumb to another, attached is my antenna coupling factor = 1 design and where it may be placed to fully ensure TE013 excitement and fully couple to the resonant EM waves. Will be supported on 3 threaded quartz rods with will allow the loop's orientation to be adjustment to get it just right. BTW thanks SeaShells for the quartz rod idea.
Next issue is to design a loop of the correct diameter and impedance. GrayBeardSysEng can you assist?
Once the loop antenna design is established, then need to come up with a new frustum design that will put the loop diameter in the centre of the centre TE013 H field lobe.
Easy peasy right?
Your antenna location looks good.
The devil is in the tiny details, I'm glad you got that leak figured out, leaking is bad. :) I know you're a geekster, excited to get back to work with a "new" soldering iron.Did you ever find out what was causing the microwave detector to be set off on the small end?
Shoddy construction and a grossly oversensitive detector. Rodal posted a link to a paper that described my detector as garbage (in slightly nicer words). The calibration is off significantly. I moved it outside of the cage and have a couple of the Diode/LED Popsicle stick detectors from http://www.repairfaq.org/sam/micfaq.htm#micsimkleak inside where I can visually check them before opening.
Thanks for checking up on me. I'm supposed to get a new soldering iron today and can get back to work.
Terrific!Ds = 6,25NSF-1701 update...all is now complete and the unit is mounted on the balance beam including oil dampener plus electrodes/cups waiting for galinstan! I't try and do a video walkound of the completed test stand tonight. Once the galinstan arrives, I'll do the test. Still have to attach laser and set up mirrors and target, but for all intents and purposes...its ready to go! Wish me luck. 8)
If you have the time would you please measure your as built frustum dimensions and post so I can do a bit of work with my higher resolution spreadsheet.
Have you used a spectrum analyser to measure the freq spread and energy distribution of your magnetron under the load of the frustum? If not, if possible, please do so as that data may help to get a good idea of how much of the magnetron's output power spectrum will be able to form resonance and then to generate Force.
The idea is to try to avoid as much as possible what Prof Yang ran into where her frustum input bandwidth (tiny rectangle lower left in all the images) was very much out of alignment with the power output spectrum of the magnetron.
Db = 11.01
L = 10.2 not including Db convex of abt 0,2 inches
No spectrum analysis yet. Will borrow handheld after first test. Basically, this is a stretched nasa/shawyer frustum using higher power and copper mesh on sides and Db. Insertion point from Ds in same spot as nasa loop. Test will be Ds facing down, working against convection, like lulian did. Pwr 900 watts. Test cycle times 1 minute at 100% and 5 minutes at 30% magnetron cycle time. 95 degrees in shop and high humidity...no video shots tonight, will try for Friday.
No, since I am an individual only, building this at home with no lab, I do not expect any further development on NSF-1701. The only way this could change is if I were to be sponsored to do so, but that is a very costly proposition. Full-time emdrive development is best left for industry or government/university research labs. Unfortunately, these are not forthcoming in their process...very secretive.Terrific!Ds = 6,25NSF-1701 update...all is now complete and the unit is mounted on the balance beam including oil dampener plus electrodes/cups waiting for galinstan! I't try and do a video walkound of the completed test stand tonight. Once the galinstan arrives, I'll do the test. Still have to attach laser and set up mirrors and target, but for all intents and purposes...its ready to go! Wish me luck. 8)
If you have the time would you please measure your as built frustum dimensions and post so I can do a bit of work with my higher resolution spreadsheet.
Have you used a spectrum analyser to measure the freq spread and energy distribution of your magnetron under the load of the frustum? If not, if possible, please do so as that data may help to get a good idea of how much of the magnetron's output power spectrum will be able to form resonance and then to generate Force.
The idea is to try to avoid as much as possible what Prof Yang ran into where her frustum input bandwidth (tiny rectangle lower left in all the images) was very much out of alignment with the power output spectrum of the magnetron.
Db = 11.01
L = 10.2 not including Db convex of abt 0,2 inches
No spectrum analysis yet. Will borrow handheld after first test. Basically, this is a stretched nasa/shawyer frustum using higher power and copper mesh on sides and Db. Insertion point from Ds in same spot as nasa loop. Test will be Ds facing down, working against convection, like lulian did. Pwr 900 watts. Test cycle times 1 minute at 100% and 5 minutes at 30% magnetron cycle time. 95 degrees in shop and high humidity...no video shots tonight, will try for Friday.
Can't wait to see the final results! Sir, do you intend to experiment with silver-plated cavity or liquid N2 cooled one? That'll be great.
I have modelled the Yang-Shell frustum with the antenna located near the big end. I have made 3 meep runs, one each for 32, 64 and 128 complete cycles with the final 14 time slices saved, a slice each one-tenth cycle. I have generated and uploaded the csv file data sets for Dr. Rodal's attention.Since the csv files quoted in your message above turned out to be for the Yang/Shell cone with the antenna near the small base, a clarification is needed;
First, the 32 cycle run here:
https://drive.google.com/folderview?id=0B1XizxEfB23tfmFENmwzYzZ5aTNVaW5sWC1YYVl5Qm4yQ3J5SmhtTkVnYUxXYUJMZzZVa1E&usp=sharing (https://drive.google.com/folderview?id=0B1XizxEfB23tfmFENmwzYzZ5aTNVaW5sWC1YYVl5Qm4yQ3J5SmhtTkVnYUxXYUJMZzZVa1E&usp=sharing)
Second, the 64 cycle run here:
https://drive.google.com/folderview?id=0B1XizxEfB23tfmlwOWVvbVB1aHA0NkMtQ0dtUjFuZks2NzZ2MGxXdWhkUTEyWWNxd2hPalE&usp=sharing (https://drive.google.com/folderview?id=0B1XizxEfB23tfmlwOWVvbVB1aHA0NkMtQ0dtUjFuZks2NzZ2MGxXdWhkUTEyWWNxd2hPalE&usp=sharing)
And lastly, the 128 cycle run here:
https://drive.google.com/folderview?id=0B1XizxEfB23tfmRvWXRHM0xWMGRpWU84RlNwQktDR3dqZWpfVDBhbEhDR2RwMEJYMERDVEE&usp=sharing (https://drive.google.com/folderview?id=0B1XizxEfB23tfmRvWXRHM0xWMGRpWU84RlNwQktDR3dqZWpfVDBhbEhDR2RwMEJYMERDVEE&usp=sharing)
My apologises to SeeShells, as the png-view files are not yet available. We are working on it. I note that the Quality factor calculated by Harminv for this antenna configuration puts it well into the superconducting cavity arena. I am anxious to see the png views myself because if my thought that evanescent waves actually accomplish their superluminal behaviour via a form of tunnelling, then with this high Q model, there should be enough energy stored within the cavity to trigger tunnelling through the bases. ...
Are you still looking at this September (barely a month from now) to broadcast your EM Drive rotating rig test results?No, since I am an individual only, building this at home with no lab, I do not expect any further development on NSF-1701. The only way this could change is if I were to be sponsored to do so, but that is a very costly proposition. Full-time emdrive development is best left for industry or government/university research labs. Unfortunately, these are not forthcoming in their process...very secretive.
What I find very interesting is Prof Yang's experimental data showing 4N/kW using a frustum with a Q of 1,500 and her 2013 equations suggesting exciting in a TE mode may increase end plate Force generation by a factor of 100 over excitation in a TM mode excitation.
Additionally the paper X-Ray shared, which shows if your antenna coupling factor is in the toilet, then your operational Q is likewise in the toilet.
All this excites me that there may be a doorway, using several synergistic effects to 300N/kW or higher non superconducting EMDrives.
But 1st back to my new coupling factor = 1 excitation antenna design and the EMDrive dimensional mods necessary to make it work.
Are you still looking at this September (barely a month from now) to broadcast your EM Drive rotating rig test results?
Expect to have some data published my end Sept. My radiation treatment starts mid Sept to end Oct but docs say should have minimal effect on my workshop time.
This new antenna design is not for 1st test unit. Have 5 variations in mind to dev higher specific Force.
I'm surprised that you think the protocol I described is that flawed. Obviously, as well, you'd want to repeat the experiment with the other one powered and the original (powered) one now unpowered.It is way, way too early to start jumping to conclusions. Anyone who does is not being fair. Until open and replicated experimental data is available, it's all noise as far as I'm concerned. As matters stand, there is nothing that is open and replicated.
The ironclad test is a space test. This cannot readily be fooled with artifacts. What's required for that is twin units in reasonably close proximity, one powered and one not, and in all other respects identical.
I know I'm a broken record, but IMHO there are many more uncontrollable favors in low earth orbit than in the lab, considering the minscule power available for the thruster on a cubesat.
In theory, the protocol is Ok, I just don't think it's practical with inexpensive satellites like cubesats. To do what you are suggesting, you would have to:
1) Ensure identical deployment conditions. Any difference in initial velocity between the two sats would manifest itself as ever-increasing separation with time - just the effect you are looking for as a thrust indicator. Take a look at the video here:
http://nanoracks.com/products/smallsat-deployment/
At about 0:19 five cubesats are deployed and begin to develop differential velocities almost immediately. In theory you could deployed the two sats joined and then separate with springs, but then you introduce the uncertainty of the separation dynamics.
2) Ensure identical orientation of the two sats (and appendages such as solar wings) with respect to the velocity vector, or the difference in aspect will result in differential drag and will again mimic the thrust signature.
3) Very accurately track the two sats. Space Command radars will obtain tracking information, but this is usually only updated every few days. Intermediate orbit prediction is done by computer propagation of the Space Command solutions. These typically do not provide the kind of accuracy I suspect you would want.
With enough complexity, all of these issues could be overcome. I just don't think it would be an inexpensive undertaking. I would certainly rather put that money into more sophisticated ground testing first.
I'm still trying to put together a paper on the subject. I've got the drag modeling done, but need to formulate the conclusions.
Great job. What you're doing here is essentially a calibration. I envisage the drive-to-drive distance measured by onboard LIDAR. Now with calibration, one can power on one of the modules. Or use a 3rd as the observation platform. I think maintaining orientation wrt the thrust vector is one of the biggest challenges.
So, been thinking about a suitable lab in case further experimentation on NSF-1701 is desired. Here's a stream of consciousness list of the test gear I'd like to get my hands on (all calibrated with computer interface, RF stuff 3 GHz minimum):Tools to make advanced frustums wrt machine shop tools.
Faraday cage (small room size)
Spectrum analyzer
VNA
Vacuum chamber
Weight scales 0.001g resolution
MW leakage meter
EMF meter
Ion counter
Geiger counter
Thermal imager
Air flow meter
Thermometer
Humidity sensor
Laser interferometer
Signal generator
Return loss bridge
Power meter
Dual channel oscilloscope
16 channel data logger
Computer
Custom software (aka LabView, etc)
OK, what are we missing...hmmm
<edit> I stopped counting at $100,000
Good catch shell, of course...looks like my estimate doubled to about $400K total not including building.So, been thinking about a suitable lab in case further experimentation on NSF-1701 is desired. Here's a stream of consciousness list of the test gear I'd like to get my hands on (all calibrated with computer interface, RF stuff 3 GHz minimum):Tools to make advanced frustums wrt machine shop tools.
(...)OK, what are we missing...hmmm
<edit> I stopped counting at $100,000
The "antenna" is really just 1 coil of a solenoid, designed to create a magnetic field axial in the frustum and centred in the middle lobe of a TE013 resonate mode.
The antennas in the sketch don't work as a loop! The loop has to be in contact to the other potential, in this case the frustum, and better the length of the loop is max a half wavelength ;)
In the sketch the wave would travel along the feed and split into two parts, this parts cancel each other at half the way along the ring.. itś like two dipoles in opposite phi directions...
No. please look at the NASAloop picture. One end of the wire is in contact to the GND and that is the way it will work as a loop.
The ground at the end of the loop is correct, the other must be connected to the HF source. (Galvanic coupling or Capacitor to the ground will work. http://forum.nasaspaceflight.com/index.php?topic=37642.msg1410718#msg1410718 )The "antenna" is really just 1 coil of a solenoid, designed to create a magnetic field axial in the frustum and centred in the middle lobe of a TE013 resonate mode.
That's exactly what I thought and wanted to show in my own sketch (a one-loop solenoid put exactly in the lobe of the excited mode) but X_RaY then stated:The antennas in the sketch don't work as a loop! The loop has to be in contact to the other potential, in this case the frustum, and better the length of the loop is max a half wavelength ;)
In the sketch the wave would travel along the feed and split into two parts, this parts cancel each other at half the way along the ring.. itś like two dipoles in opposite phi directions...No. please look at the NASAloop picture. One end of the wire is in contact to the GND and that is the way it will work as a loop.
So maybe my sketch wasn't so greatly executed, showing a one-loop solenoid. The loop antenna in Eagleworks' picture is not a solenoid, it is like a little horseshoe, one extremity being grounded:
(http://forum.nasaspaceflight.com/xindex.php,qaction=dlattach,3Btopic=38203.0,3Battach=1057032,3Bimage.pagespeed.ic.AwGtB_pjPB.jpg)
Anyone remember how long it took our Roumanian friend Iulian to build and test his rig? As I recall it was quite speedy.Not exactly, but think it was less than 1 month. OK, you're about to hammer me, aren't you DM ;)
Poke poke poke. We need to find a shower curtain to hang them off from. ;)Anyone remember how long it took our Roumanian friend Iulian to build and test his rig? As I recall it was quite speedy.Not exactly, but think it was less than 1 month. OK, you're about to hammer me, aren't you DM ;)
Anyone remember how long it took our Roumanian friend Iulian to build and test his rig? As I recall it was quite speedy.Yea, that was quite speedy, but his setup was not very complex. Same for measurement, so not many sensors hence not much of a data. But yes, the most important quantity - thrust has been measured.
Good catch shell, of course...looks like my estimate doubled to about $400K total not including building.So, been thinking about a suitable lab in case further experimentation on NSF-1701 is desired. Here's a stream of consciousness list of the test gear I'd like to get my hands on (all calibrated with computer interface, RF stuff 3 GHz minimum):Tools to make advanced frustums wrt machine shop tools.
(...)OK, what are we missing...hmmm
<edit> I stopped counting at $100,000
TE012 excitation
External magnetron coupled to 4 loops internally at H plane 180 phase shifted […] And two additional and equal length but added lambda/4 for a 90 phase shift for a total of 180 deg on each. Quad loops ~1/5 WL 10 gauge copper loops excited in the H plane supported by the vertical tuning quartz rod.Could you post a drawing showing the antennas shape and placement?
TE012 excitation
For the new dimensions you provided I get a very good TE013 excitation at 2.47 GHz, according to TT's spreadsheet.
This is for flat ends. Do you plan flat or spherical ends?External magnetron coupled to 4 loops internally at H plane 180 phase shifted […] And two additional and equal length but added lambda/4 for a 90 phase shift for a total of 180 deg on each. Quad loops ~1/5 WL 10 gauge copper loops excited in the H plane supported by the vertical tuning quartz rod.Could you post a drawing showing the antennas shape and placement?
TE012 excitation
For the new dimensions you provided I get a very good TE013 excitation at 2.47 GHz, according to TT's spreadsheet.
This is for flat ends. Do you plan flat or spherical ends?External magnetron coupled to 4 loops internally at H plane 180 phase shifted […] And two additional and equal length but added lambda/4 for a 90 phase shift for a total of 180 deg on each. Quad loops ~1/5 WL 10 gauge copper loops excited in the H plane supported by the vertical tuning quartz rod.Could you post a drawing showing the antennas shape and placement?
NSF-1701 Update, pass it along, I will only post it here on NSF:
First "Flight" Test Tuesday, August 25, 2015 2:00 PM Eastern Standard Time USA, 18:00 Hours UTC
It will be a recorded video, not live as EM interference trashes WiFi camera, too long of a run for USB cam and wired security cam not able to interface with Ustream (don't ask - long story). Also, it was suggested not to go live if a problem occurs; causing grief to both myself and audience. Be assured there will be no video editing involved.
Will post here when the video is uploaded to my youtube channel on Tuesday. Probably will take about 30 minutes to upload and process on the youtube site.
<edit>
Was just informed that my next scheduled appearance on Dark Matters Digital Network's Other Side of Midnight will be next Tuesday/Wednesday 12:00 Midnight to 2:00 AM Pacific Daylight Time. I will be discussing NSF-1701 results and unlike the last appearance, have time to take questions.
I was informed by the producer that several emailers mentioned my last appearance was their favorite show (which is new on the network). I credit Mr. Hoagland for being well-informed on the topic and very interested in getting the real story out there from a grass-roots design perspective. Should be fun.
2 things, appearance moved to next Thursday/Friday.NSF-1701 Update, pass it along, I will only post it here on NSF:
First "Flight" Test Tuesday, August 25, 2015 2:00 PM Eastern Standard Time USA, 18:00 Hours UTC
It will be a recorded video, not live as EM interference trashes WiFi camera, too long of a run for USB cam and wired security cam not able to interface with Ustream (don't ask - long story). Also, it was suggested not to go live if a problem occurs; causing grief to both myself and audience. Be assured there will be no video editing involved.
Will post here when the video is uploaded to my youtube channel on Tuesday. Probably will take about 30 minutes to upload and process on the youtube site.
<edit>
Was just informed that my next scheduled appearance on Dark Matters Digital Network's Other Side of Midnight will be next Tuesday/Wednesday 12:00 Midnight to 2:00 AM Pacific Daylight Time. I will be discussing NSF-1701 results and unlike the last appearance, have time to take questions.
I was informed by the producer that several emailers mentioned my last appearance was their favorite show (which is new on the network). I credit Mr. Hoagland for being well-informed on the topic and very interested in getting the real story out there from a grass-roots design perspective. Should be fun.
Might I humbly suggest you make available your coordinates and stream a reasonably accurate time hack? This will allow those interested to compute magnetic field vectors, heliocentric velocities, etc.
... What is a time hack? Sorry don't follow...
... What is a time hack? Sorry don't follow...
If you include your geographic GPS coordinates and a video of say your cell phone showing your Greenwich Mean Time to the nearest second (or better) (a time hack), as well as the direction of north relative to your experiment, it would allow for calculation of the velocity of your workshop within the solar system including the orbital velocity of earth around the sun and the rotational velocity of the earth. This is just in case these motions are in anyway are connected to the forces that you measure.
If you cut the video at any point then when you restart it you should ideally include another "time hack" (video shot of your GMT time on say your cell phone) to re-synchronize your experiment to your local velocity calculations.
If you know your local magnetic deviation from true north that might also be helpful.
Well, I'm glad we all agree on that one.Well, the answer is simple, everything else being the same, just substitute your value of Q in the appropriate formula.
So, as I said before, one can probably boost the Q by a factor of 2.8.
Now the question is what is the amount of thrust we can get from this boost?
Flat ends. Try as I might, I cannot get a uniform curve on an english wheel, miss my old tool room lathe.Maybe try hydroforming? Works for fuel tanks. Looks fun anyway.
Shell
What's the name of the website you can listen to the digital radio show on.http://othersideofmidnight.com
An update on the finances of SPR. The information presented in the following is current as of March 31st 2015.
Here is the most recent balance sheet (https://s3-eu-west-1.amazonaws.com/document-api-images-prod/docs/bzrCMmEtGgloc74n9a4tvKWRCgx50t96nhrU4CUZZZY/application-pdf?AWSAccessKeyId=ASIAIT35MGBV6PXVZWUA&Expires=1440180826&Signature=jDDJtNAaibcXN3PqaAMbPk6Gnyc%3D&x-amz-security-token=AQoDYXdzEKn%2F%2F%2F%2F%2F%2F%2F%2F%2F%2FwEa4AP6wl8hym2jxstO%2BQzP8zKh4WjgZaxQQi%2BEX1Ta2i0gcYIEcZizfW5q6k2UvY%2Bamu1P22%2FqnF6fESRXsu1RhOIGxZ%2FkI5jej8h8u0xly0%2B3JvGCRbFI0p9KGvtnZX81DSe71y5kDg0QWAS4dTzi6WzlHccLP5v%2Br1P1mpUqBLqbk08Xeec4ghnSPwCwEhwPEPaXT3YsZpHCFwxpS1wmWJ23GG41HfVcr9%2B966DbT%2FDI6TZCo3EhmSgjdrJlLNM%2F9obiRhQA5Bwg%2BMd49gB8ktZGHeB44aDfitnZvMIUyawl1cmBSr581tTDO7HkJhwLSUGujObd32xLRDTSGa4c%2Bnhx4XahUI%2FxPS75NcKLhre55vkt29Bi02bgwmkrkwdtonU%2FFglu1Rbg7daiN74XUMVtlXHlzrEXXicFdu8w1mK9S0%2BgsrzRkacHWpySNhuHwtOgZgLw52sDpriY5TMU9KCOgk81nfscdgOLJPrGqs6XWMx8IPODKl0WyHusXfpe4qmTR2tmOyqlFgMS2%2BKc4SpoweqWAQ43YtU3T6hVLjXLz7LOjOm6yvu4EB3HV1eN6YJESK3XM00RNtu41QuRibiI%2BlQIDInqKFWhInFWrr3zA3uqAH2B9EhNG9LmdheQFmAg6ozdrgU%3D), which is available from the public records at the companies house database: https://beta.companieshouse.gov.uk/company/04097991/filing-history
Summary:
No change in tangible assets from 2014-2015, meaning no new equipment has been purchased.
SPR is holding more cash than it has previously (about 15,000 pounds compared to 5,000 pounds).
Most importantly, it has paid off a portion of its long term debt, going from 240,000 to 195,000 pounds.
It currently has negative net assets of 185,000 pounds, less than the 235,000 as of the same date in 2014. With only the balance sheet and no income statement, it is impossible to deduce where the cash to pay off the long term debt came from or if the debt was perhaps forgiven instead. Investment can be ruled out however, as the number of outstanding shares has not changed since 2014.
Previous posts on this subject are linked below:
http://forum.nasaspaceflight.com/index.php?topic=37642.msg1394575#msg1394575
http://forum.nasaspaceflight.com/index.php?topic=37642.msg1396231#msg1396231
http://forum.nasaspaceflight.com/index.php?topic=37642.msg1396346#msg1396346
http://forum.nasaspaceflight.com/index.php?topic=37642.msg1396365#msg1396365
You have to root for small businesses everywhere. One fell swoop from a wealthy competitor can destroy hard-earned businesses, some family operated. This is nothing new as the Robber Barons around the turn of the 20th century, crushed many. Like them or not, small companies are the lifeblood of innovation.An update on the finances of SPR. The information presented in the following is current as of March 31st 2015.
Here is the most recent balance sheet (https://s3-eu-west-1.amazonaws.com/document-api-images-prod/docs/bzrCMmEtGgloc74n9a4tvKWRCgx50t96nhrU4CUZZZY/application-pdf?AWSAccessKeyId=ASIAIT35MGBV6PXVZWUA&Expires=1440180826&Signature=jDDJtNAaibcXN3PqaAMbPk6Gnyc%3D&x-amz-security-token=AQoDYXdzEKn%2F%2F%2F%2F%2F%2F%2F%2F%2F%2FwEa4AP6wl8hym2jxstO%2BQzP8zKh4WjgZaxQQi%2BEX1Ta2i0gcYIEcZizfW5q6k2UvY%2Bamu1P22%2FqnF6fESRXsu1RhOIGxZ%2FkI5jej8h8u0xly0%2B3JvGCRbFI0p9KGvtnZX81DSe71y5kDg0QWAS4dTzi6WzlHccLP5v%2Br1P1mpUqBLqbk08Xeec4ghnSPwCwEhwPEPaXT3YsZpHCFwxpS1wmWJ23GG41HfVcr9%2B966DbT%2FDI6TZCo3EhmSgjdrJlLNM%2F9obiRhQA5Bwg%2BMd49gB8ktZGHeB44aDfitnZvMIUyawl1cmBSr581tTDO7HkJhwLSUGujObd32xLRDTSGa4c%2Bnhx4XahUI%2FxPS75NcKLhre55vkt29Bi02bgwmkrkwdtonU%2FFglu1Rbg7daiN74XUMVtlXHlzrEXXicFdu8w1mK9S0%2BgsrzRkacHWpySNhuHwtOgZgLw52sDpriY5TMU9KCOgk81nfscdgOLJPrGqs6XWMx8IPODKl0WyHusXfpe4qmTR2tmOyqlFgMS2%2BKc4SpoweqWAQ43YtU3T6hVLjXLz7LOjOm6yvu4EB3HV1eN6YJESK3XM00RNtu41QuRibiI%2BlQIDInqKFWhInFWrr3zA3uqAH2B9EhNG9LmdheQFmAg6ozdrgU%3D), which is available from the public records at the companies house database: https://beta.companieshouse.gov.uk/company/04097991/filing-history
Summary:
No change in tangible assets from 2014-2015, meaning no new equipment has been purchased.
SPR is holding more cash than it has previously (about 15,000 pounds compared to 5,000 pounds).
Most importantly, it has paid off a portion of its long term debt, going from 240,000 to 195,000 pounds.
It currently has negative net assets of 185,000 pounds, less than the 235,000 as of the same date in 2014. With only the balance sheet and no income statement, it is impossible to deduce where the cash to pay off the long term debt came from or if the debt was perhaps forgiven instead. Investment can be ruled out however, as the number of outstanding shares has not changed since 2014.
Previous posts on this subject are linked below:
http://forum.nasaspaceflight.com/index.php?topic=37642.msg1394575#msg1394575
http://forum.nasaspaceflight.com/index.php?topic=37642.msg1396231#msg1396231
http://forum.nasaspaceflight.com/index.php?topic=37642.msg1396346#msg1396346
http://forum.nasaspaceflight.com/index.php?topic=37642.msg1396365#msg1396365
Interesting. The fact that SPR is paying off, and reducing debt is positive, as well as raising the amount of cash is positive. It shows that he intends to keep SPR as a viable company.
Do you see any evidence of:
1) SPR having any employees other than Roger Shawyer?
2) SPR being associated with any companies in any projects?
3) SPR receiving any recent royalties from licensees?
4) SPR receiving any recent loans?
Any expenditures needed to make the superconducting flying vehicles a reality? (my understanding is NO, since you write " no new equipment has been purchased. SPR is holding more cash than it has previously (about 15,000 pounds compared to 5,000 pounds").
Under UK corporate tax law, could an owner of a small company inject cash into a privately held company to shelter income taxes at the individual level and shift them to the company level, by paying off corporate debt?
...You have to root for small businesses everywhere. One fell swoop from a wealthy competitor can destroy hard-earned businesses, some family operated. This is nothing new as the Robber Barons around the turn of the 20th century, crushed many. Like them or not, small companies are the lifeblood of innovation.Yes, I certainly root for small businesses everywhere. Viva entrepreneurship :)
Do you see any evidence of:
1) SPR having any employee other than Roger Shawyer?
2) SPR being associated with any companies in any projects?
3) SPR receiving any recent royalties from licensees?
4) SPR receiving any recent investments?
5) SPR receiving any recent loans?
Do you see anything on these reports concerning SPR efforts nowadays beyond Shawyer himself?
Any expenditures needed to make the superconducting flying vehicles a reality? Or any income showing license royalties?
Do you see anything on these reports concerning SPR efforts nowadays beyond Shawyer himself?
Any expenditures needed to make the superconducting flying vehicles a reality? Or any income showing license royalties?
Concerning paying off debt, under UK corporate tax law, could an owner of a small company inject cash into a privately held company to shelter income taxes at the individual level and shift them to the company level, by paying off corporate debt?
Is the CEO/Manager of SPR receiving a salary? Or is the salary being forgone?
Where there is a will there is a way. I've done it three times with businesses, from nothing to something....You have to root for small businesses everywhere. One fell swoop from a wealthy competitor can destroy hard-earned businesses, some family operated. This is nothing new as the Robber Barons around the turn of the 20th century, crushed many. Like them or not, small companies are the lifeblood of innovation.Yes, I certainly root for small businesses everywhere. Viva entrepreneurship :)
(https://s-media-cache-ak0.pinimg.com/236x/ab/b8/84/abb88470a54d40f7697f1581ec02d51e.jpg)
An update on the finances of SPR. The information presented in the following is current as of March 31st 2015.
Here is the most recent balance sheet (https://s3-eu-west-1.amazonaws.com/document-api-images-prod/docs/bzrCMmEtGgloc74n9a4tvKWRCgx50t96nhrU4CUZZZY/application-pdf?AWSAccessKeyId=ASIAIT35MGBV6PXVZWUA&Expires=1440180826&Signature=jDDJtNAaibcXN3PqaAMbPk6Gnyc%3D&x-amz-security-token=AQoDYXdzEKn%2F%2F%2F%2F%2F%2F%2F%2F%2F%2FwEa4AP6wl8hym2jxstO%2BQzP8zKh4WjgZaxQQi%2BEX1Ta2i0gcYIEcZizfW5q6k2UvY%2Bamu1P22%2FqnF6fESRXsu1RhOIGxZ%2FkI5jej8h8u0xly0%2B3JvGCRbFI0p9KGvtnZX81DSe71y5kDg0QWAS4dTzi6WzlHccLP5v%2Br1P1mpUqBLqbk08Xeec4ghnSPwCwEhwPEPaXT3YsZpHCFwxpS1wmWJ23GG41HfVcr9%2B966DbT%2FDI6TZCo3EhmSgjdrJlLNM%2F9obiRhQA5Bwg%2BMd49gB8ktZGHeB44aDfitnZvMIUyawl1cmBSr581tTDO7HkJhwLSUGujObd32xLRDTSGa4c%2Bnhx4XahUI%2FxPS75NcKLhre55vkt29Bi02bgwmkrkwdtonU%2FFglu1Rbg7daiN74XUMVtlXHlzrEXXicFdu8w1mK9S0%2BgsrzRkacHWpySNhuHwtOgZgLw52sDpriY5TMU9KCOgk81nfscdgOLJPrGqs6XWMx8IPODKl0WyHusXfpe4qmTR2tmOyqlFgMS2%2BKc4SpoweqWAQ43YtU3T6hVLjXLz7LOjOm6yvu4EB3HV1eN6YJESK3XM00RNtu41QuRibiI%2BlQIDInqKFWhInFWrr3zA3uqAH2B9EhNG9LmdheQFmAg6ozdrgU%3D), which is available from the public records at the companies house database: https://beta.companieshouse.gov.uk/company/04097991/filing-history
Summary:
No change in tangible assets from 2014-2015, meaning no new equipment has been purchased.
SPR is holding more cash than it has previously (about 15,000 pounds compared to 5,000 pounds).
Most importantly, it has paid off a portion of its long term debt, going from 240,000 to 195,000 pounds.
It currently has negative net assets of 185,000 pounds, less than the 235,000 as of the same date in 2014. With only the balance sheet and no income statement, it is impossible to deduce where the cash to pay off the long term debt came from or if the debt was perhaps forgiven instead. Investment can be ruled out however, as the number of outstanding shares has not changed since 2014.
Previous posts on this subject are linked below:
http://forum.nasaspaceflight.com/index.php?topic=37642.msg1394575#msg1394575
http://forum.nasaspaceflight.com/index.php?topic=37642.msg1396231#msg1396231
http://forum.nasaspaceflight.com/index.php?topic=37642.msg1396346#msg1396346
http://forum.nasaspaceflight.com/index.php?topic=37642.msg1396365#msg1396365
Dr. Rodal,
I have been watching your and aero's work very closely, and daring risking to say something stupid due to my lack of knowledge, it seems you are on the brink of something momentous.
Because, if I understand what you are saying, you seem to be implying that by using purely classical physics in the form of Maxwell's equations and what the Meep program can process and calculate, there is an actual asymmetry of forces emerging inside the truncated cone-shaped resonating microwave cavity (aka frustum), with the calculated geometries, frequencies and antenna position (near the big base).
It seems that the model also shows that forces do cancel out when the antenna is placed close to the small base, something that we didn't know before, and that seems to contradict experimental data showing thrust in either case (probably because we are mixing up spurious error sources with the real force signature).
But the biggest news, at least for me, is that the classical calculations you and aero made falsify Greg Egan's model (the best critical model so far) saying that every force inside the Emdrive cancels out to zero, as the classical interpretation would expect, because we do expect that no device can propel itself in space without the application of the generally accepted forms of action/reaction principle, either by expelling propellant or reacting against an external field.
That such a thing may be possible at all and calculated using only classical physics is an astounding result indeed. And I understand why you would certainly like to have experimental confirmation of its validity, because such a result, if confirmed, would certainly rock our understanding of physics, where such a thing arising from purely classical formulas and their application is a completely unexpected result.
Dr. Rodal,
I have been watching your and aero's work very closely, and daring risking to say something stupid due to my lack of knowledge, it seems you are on the brink of something momentous.
Because, if I understand what you are saying, you seem to be implying that by using purely classical physics in the form of Maxwell's equations and what the Meep program can process and calculate, there is an actual asymmetry of forces emerging inside the truncated cone-shaped resonating microwave cavity (aka frustum), with the calculated geometries, frequencies and antenna position (near the big base).
It seems that the model also shows that forces do cancel out when the antenna is placed close to the small base, something that we didn't know before, and that seems to contradict experimental data showing thrust in either case (probably because we are mixing up spurious error sources with the real force signature).
But the biggest news, at least for me, is that the classical calculations you and aero made falsify Greg Egan's model (the best critical model so far) saying that every force inside the Emdrive cancels out to zero, as the classical interpretation would expect, because we do expect that no device can propel itself in space without the application of the generally accepted forms of action/reaction principle, either by expelling propellant or reacting against an external field.
That such a thing may be possible at all and calculated using only classical physics is an astounding result indeed. And I understand why you would certainly like to have experimental confirmation of its validity, because such a result, if confirmed, would certainly rock our understanding of physics, where such a thing arising from purely classical formulas and their application is a completely unexpected result.
I read your understanding as correct for case (b), (antenna near the big base), but my classical physics interpretation is that it must cancel out through the RF and power feed if the RF feed and power come from a stationary location that cannot move. Therefore deltaMass and frobnicat must be given credit for emphasizing that a true test of the EM Drive must contain all components together in one mobile package. TheTraveller and the Aachen team must be given credit for designing such experiments where everything will be together in one mobile package. Case (a) antenna at small end is also interesting as classical physics would predict no forces for that case. Thus, I hope that rfmwguy and Shell will conduct experiments with the RF feed in separate tests being near the small end and near the big end to see how it compares with the Meep results :)
It would be most interesting for TheTraveller to conduct experiments with the antenna near the big base and with the antenna near the small base to see what difference it makes on his experiment
If they are now being financed by an arm of somebody's DOD for this alleged drone of their's and if that's coming from a black budget then nothing will appear through the books here. In fact when dealing with such contracts I would argue such conventional analysis is not all that useful. Especially if this is more than likely being put through a specially created & separate shell corporation, which unless you know the name of you will not get anywhere with & even then I'd doubt you'd find much. Black budget accounting is specifically designed to be invisible as it possible can be to defeat such enquiries.
If they are now being financed by an arm of somebody's DOD for this alleged drone of their's and if that's coming from a black budget then nothing will appear through the books here. In fact when dealing with such contracts I would argue such conventional analysis is not all that useful. Especially if this is more than likely being put through a specially created & separate shell corporation, which unless you know the name of you will not get anywhere with & even then I'd doubt you'd find much. Black budget accounting is specifically designed to be invisible as it possible can be to defeat such enquiries.
Fair point. I appreciate the perspective.
Personally, I very much doubt that they are being financed by any branch of any defense organization however.
I mean; Shawyer is actively disclosing his plans and designs, as well as previous experimental work to a man (TheTraveller) who just emailed him out of the blue. What's more, he's given permission for TheTraveller to share all that information on multiple public forums (NSF, reddit).
Is it really likely that a mysterious organization is going to great lengths (or any lengths for that matter) to obscure the financials of SPR, knowing that SPRs one and only employee has openly disclosed the development of their black project to the public at large?
Anyone see a trend where experiments with the frustum oriented vertically seem to have more thrust than horizontal ones? There isn't much to go on yet. I remember that from the Romanian guy's test (he also moved the magnetron at the same time though.) Were the Chinese tests all vertical? Something to keep an eye on.Well, that might be correlated to the magnetic field of the Earth or some interference with the AC, still EW (and Tajmar) vacuum chamber seems to be a pretty good magnetic shield as a whole.
...
{snip}
Is the CEO/Manager of SPR receiving a salary? Or is the salary being forgone?
Shawyer (in his capacity as CEO/Manager) has forgone his salary for the last three years as evidenced by the stability of the accounts and as explicitly remarked to me the by TheTraveller, so I presume Shawyer told him as much.
@SeeShells,Ok I understand. I'm still laying out the frustum and don't have a full layout.
I've a little problem modelling your Crazy-Eddie thruster. (I'm abbreviating it to a C-E model to keep names short.)
1) Where do I start with the location of the small base reflecting surface - I know it moves?
2) I see small diameters of 0.16 meters and on the graphic, 0.1603 - what is up with that?
3) Where really is the large base reflecting surface?
Here is an image showing my progress so far. But the C-E cavity is another big one so I'm forced to reduce resolution to keep the run times down. Once I add width to accommodate waveguide feeds, we'll need some volunteers to make runs of any decent duration.
aero
@SeeShells,Ok I understand. I'm still laying out the frustum and don't have a full layout.
I've a little problem modelling your Crazy-Eddie thruster. (I'm abbreviating it to a C-E model to keep names short.)
1) Where do I start with the location of the small base reflecting surface - I know it moves?
2) I see small diameters of 0.16 meters and on the graphic, 0.1603 - what is up with that?
3) Where really is the large base reflecting surface?
Here is an image showing my progress so far. But the C-E cavity is another big one so I'm forced to reduce resolution to keep the run times down. Once I add width to accommodate waveguide feeds, we'll need some volunteers to make runs of any decent duration.
aero
The large plate top starts right at the sidewall boundary up from the bottom .0205m .
The fulcrum cavity length from the large center endplate to the small endplate ends within the tuning cavity tube and is up from the large center plate .2620m and stops in the tuning chamber 0.0376m.
You need to take off the straight section at the bottom just like all the others. The top is fine as long as the cavity in the tuning tube is 0.0376m before it ends for a total of 0.2620m cavity length.
Still modeling and rechecking.
Thanks
Shell
@SeeShells,Ok I understand. I'm still laying out the frustum and don't have a full layout.
I've a little problem modelling your Crazy-Eddie thruster. (I'm abbreviating it to a C-E model to keep names short.)
1) Where do I start with the location of the small base reflecting surface - I know it moves?
2) I see small diameters of 0.16 meters and on the graphic, 0.1603 - what is up with that?
3) Where really is the large base reflecting surface?
Here is an image showing my progress so far. But the C-E cavity is another big one so I'm forced to reduce resolution to keep the run times down. Once I add width to accommodate waveguide feeds, we'll need some volunteers to make runs of any decent duration.
aero
The large plate top starts right at the sidewall boundary up from the bottom .0205m .
The fulcrum cavity length from the large center endplate to the small endplate ends within the tuning cavity tube and is up from the large center plate .2620m and stops in the tuning chamber 0.0376m.
You need to take off the straight section at the bottom just like all the others. The top is fine as long as the cavity in the tuning tube is 0.0376m before it ends for a total of 0.2620m cavity length.
Still modeling and rechecking.
Thanks
Shell
So If I understand you right, the join of the conic section and the tuning tube is 0.2244 meters up from the large end plate which is at the big end of the conic section. The small end plate is then 0.0376m up from that join. Or do I have it backwards? This is what I understand now.
But what is the size of diameter of the tuning tube and the tuning plate (small base plate)? They can't be the same size so their must be a gap.
With Copper it is very easy to raise a simple uniform bowl shape. All you need is a stump with a rounded depression, and a hammer with a face that is smooth and hemispherical. A few heat cycles are needed to soften the work-hardened Copper. It takes a lot of hammering but the natural inclination of the Copper is to move into a bowl shape. I used to do a lot of that before I got into the software racket.Flat ends. Try as I might, I cannot get a uniform curve on an english wheel, miss my old tool room lathe.Maybe try hydroforming? Works for fuel tanks. Looks fun anyway.
Shell
So If I understand you right, the join of the conic section and the tuning tube is 0.2244 meters up from the large end plate which is at the big end of the conic section. The small end plate is then 0.0376m up from that join. Or do I have it backwards? This is what I understand now.
But what is the size of diameter of the tuning tube and the tuning plate (small base plate)? They can't be the same size so their must be a gap.
Small plate 160 mm, .032", O2 Free copper walls, Silver ~.30 um on endplates.
This should work just fine.
Thanks.
Shell
Check back later, have friends over.
So If I understand you right, the join of the conic section and the tuning tube is 0.2244 meters up from the large end plate which is at the big end of the conic section. The small end plate is then 0.0376m up from that join. Or do I have it backwards? This is what I understand now.
But what is the size of diameter of the tuning tube and the tuning plate (small base plate)? They can't be the same size so their must be a gap.
Small plate 160 mm, .032", O2 Free copper walls, Silver ~.30 um on endplates.
This should work just fine.
Thanks.
Shell
Check back later, have friends over.
But I thought you were going to use silver plated ceramic for the end plates? I liked that idea much better than copper end plates because of my hypothesis that thrust may be generated by tunnelling evanescent waves. A thin silver plate on ceramic would have a lot lower barrier height than copper end plates, although 30 um might be more than I'd like to see.
One thing that bugs me about my idea is that the math seems to be readily available to check for momentum from tunnelling evanescent waves, but I don't have the knowledge to apply it.
But back to the C-E drive, the small end plate cannot be the same diameter as the inner diameter of the tuning tube. You may try for the same size but it won't move if it is wedged in tightly and you want it to move. What is your expected tolerance on the two diameters? Millimetres? Hundreds of micrometers? Tens of micrometers? Evanescent waves will escape through this gap and we want to see them.
Fascinating reading about the history of the aether, its abandonment and reintroduction as "new aether" by Einstein.
https://en.wikipedia.org/wiki/Luminiferous_aether#Einstein.27s_views_on_the_aether
While reading up on resonator experiments concerning the aether, I found this which is thought-provoking:
http://vixra.org/pdf/1009.0057v3.pdf
Why over 30 years absolute motion was not detected in Michelson-type experiments
with resonators
V.V. Demjanov
He's basically saying all the negative results were wrong.
Please save us time on this. WikiP reports delta-c/c <= 10-17 from the most recent measurements. Is this the value taken by your two guys?
viXra is just about the last place to go for "information", btw.
OK, I peeked. This from arXiv critiques your sources
http://arxiv.org/abs/1404.6095
Diurnal and seasonal variations in CO2 is the likely culprit.
Thoughts to the gap...
So If I understand you right, the join of the conic section and the tuning tube is 0.2244 meters up from the large end plate which is at the big end of the conic section. The small end plate is then 0.0376m up from that join. Or do I have it backwards? This is what I understand now.
But what is the size of diameter of the tuning tube and the tuning plate (small base plate)? They can't be the same size so their must be a gap.
Small plate 160 mm, .032", O2 Free copper walls, Silver ~.30 um on endplates.
This should work just fine.
Thanks.
Shell
Check back later, have friends over.
But I thought you were going to use silver plated ceramic for the end plates? I liked that idea much better than copper end plates because of my hypothesis that thrust may be generated by tunnelling evanescent waves. A thin silver plate on ceramic would have a lot lower barrier height than copper end plates, although 30 um might be more than I'd like to see.
One thing that bugs me about my idea is that the math seems to be readily available to check for momentum from tunnelling evanescent waves, but I don't have the knowledge to apply it.
But back to the C-E drive, the small end plate cannot be the same diameter as the inner diameter of the tuning tube. You may try for the same size but it won't move if it is wedged in tightly and you want it to move. What is your expected tolerance on the two diameters? Millimetres? Hundreds of micrometers? Tens of micrometers? Evanescent waves will escape through this gap and we want to see them.
I'm looking at about a .0125mm gap. I've ordered 2 plates. The second one I'll modify for evanescent wave actions with a set pattern in the silver for just them and set a conductive seal between the plate and sidewalls. I just would like to see what meep does in the modes with the antennas you selected and not too worried about them this run.
Is that ok ?
Shell
Please save us time on this. WikiP reports delta-c/c <= 10-17 from the most recent measurements. Is this the value taken by your two guys?
viXra is just about the last place to go for "information", btw.
OK, I peeked. This from arXiv critiques your sources
http://arxiv.org/abs/1404.6095
Diurnal and seasonal variations in CO2 is the likely culprit.
The following article from Reginald Cahill (http://vixra.org/abs/1504.0125 (http://vixra.org/abs/1504.0125)) lists several physical experiences concluding to the existence of a kind of absolute reference frame : "Review of Experiments that Contradict Special Relativity and Support Neo-Lorentz Relativity: Latest Technique to Detect Dynamical Space Using Quantum Detectors"
In his article that you refer to, ("A criticism of ”gas mode ”reinterpretations of the Michelson-Morley and similar experiments."), Daniel Shanahan far from disputing the thesis of Reginald Cahill on the existence of an absolute frame, writes in support to it : "However, it is also suggested here that whether or not the absolute frame urged by these investigators is detectable, there exist compelling reasons for considering the alternative Lorentzian approach to relativity that did suppose such a frame".
Now on the analysis of the speed of light in material medium, it is really strange that Daniel Shanahan call it "Reduced phase velocity V of light". For me this speed is a real speed (with energy transport) and not a phase speed which can be as great as we want. Moreover the Maxwell equations (which are fully Lorentz transformation compatible) give a clear and invariant status to the light speed in a material medium as soon as this medium is characterized by well defined permittivity and permeability. Do you suggest that permittivity and permeability depend on the speed of the observer who measure them ?
Moreover the relativistic drag effect invoked by Daniel Shanahan in a medium moving with respect to the observer cannot be opposed to the experience proposed by Reginald Cahill (Michelson-Morley in material medium) as in this case the observer is at rest with the interferometer and its material medium (the drag effect is zero). So I don't see why if the experience proposed by Reginald Cahill shows a variation of speed it should not be linked to an anisotropy of the speed of light.
Conclusion : Let Reginald Cahill perform his proposed experience (as our friends are making their "silly" force measurement on EM cavity !!) and the Oracle will tell where is the Truth !!!
Thoughts to the gap...
So If I understand you right, the join of the conic section and the tuning tube is 0.2244 meters up from the large end plate which is at the big end of the conic section. The small end plate is then 0.0376m up from that join. Or do I have it backwards? This is what I understand now.
But what is the size of diameter of the tuning tube and the tuning plate (small base plate)? They can't be the same size so their must be a gap.
Small plate 160 mm, .032", O2 Free copper walls, Silver ~.30 um on endplates.
This should work just fine.
Thanks.
Shell
Check back later, have friends over.
But I thought you were going to use silver plated ceramic for the end plates? I liked that idea much better than copper end plates because of my hypothesis that thrust may be generated by tunnelling evanescent waves. A thin silver plate on ceramic would have a lot lower barrier height than copper end plates, although 30 um might be more than I'd like to see.
One thing that bugs me about my idea is that the math seems to be readily available to check for momentum from tunnelling evanescent waves, but I don't have the knowledge to apply it.
But back to the C-E drive, the small end plate cannot be the same diameter as the inner diameter of the tuning tube. You may try for the same size but it won't move if it is wedged in tightly and you want it to move. What is your expected tolerance on the two diameters? Millimetres? Hundreds of micrometers? Tens of micrometers? Evanescent waves will escape through this gap and we want to see them.
I'm looking at about a .0125mm gap. I've ordered 2 plates. The second one I'll modify for evanescent wave actions with a set pattern in the silver for just them and set a conductive seal between the plate and sidewalls. I just would like to see what meep does in the modes with the antennas you selected and not too worried about them this run.
Is that ok ?
Shell
Shell, is your favorite target mode still TE012? If yes the field strength(E) for this mode tend to zero near the "edge" of frustum and endplate. It is zero in the corner. There will be also no current flow between the frustum and the plate.
So if the gap is small its not "visible" from the viewpoint of this mode.
For some other mode shapes the gap can work as a slot antenna, it can radiate, not in the sense of evanescent waves.. The most interesting point is the length of the slot and thats the circumference in your case(not only the width of the gap is important).
This is an idea also thought of by Paul March too. Honesty I like the simplicity of the slot antenna Even though he was going for a TM010 mode.Thoughts to the gap...Check back later, have friends over.
Shell
Shell, is your favorite target mode still TE012? If yes the field strength(E) for this mode tend to zero near the "edge" of frustum and endplate. It is zero in the corner. There will be also no current flow between the frustum and the plate.
So if the gap is small its not "visible" from the viewpoint of this mode.
For some other mode shapes the gap can work as a slot antenna, it can radiate, not in the sense of evanescent waves.. The most interesting point is the length of the slot and thats the circumference in your case(not only the width of the gap is important).
Thoughts to the gap...
Shell
Shell, is your favorite target mode still TE012? If yes the field strength(E) for this mode tend to zero near the "edge" of frustum and endplate. It is zero in the corner. There will be also no current flow between the frustum and the plate.
So if the gap is small its not "visible" from the viewpoint of this mode.
For some other mode shapes the gap can work as a slot antenna, it can radiate, not in the sense of evanescent waves.. The most interesting point is the length of the slot and thats the circumference in your case(not only the width of the gap is important).
Good plan. For all the modes which produce currents thru the gap, a good galvanic contact is necessary. While moving the plate the S-Parameter signal will look a little noisy that depends on the contact between the frustum and the plate(will be stable again after movement). The resonant frequency could be a little bit lower than calculated for a given length (MHz range, caused by longer current paths) if the metal seal is at the outer side.Thoughts to the gap...
So If I understand you right, the join of the conic section and the tuning tube is 0.2244 meters up from the large end plate which is at the big end of the conic section. The small end plate is then 0.0376m up from that join. Or do I have it backwards? This is what I understand now.
But what is the size of diameter of the tuning tube and the tuning plate (small base plate)? They can't be the same size so their must be a gap.
Small plate 160 mm, .032", O2 Free copper walls, Silver ~.30 um on endplates.
This should work just fine.
Thanks.
Shell
Check back later, have friends over.
But I thought you were going to use silver plated ceramic for the end plates? I liked that idea much better than copper end plates because of my hypothesis that thrust may be generated by tunnelling evanescent waves. A thin silver plate on ceramic would have a lot lower barrier height than copper end plates, although 30 um might be more than I'd like to see.
One thing that bugs me about my idea is that the math seems to be readily available to check for momentum from tunnelling evanescent waves, but I don't have the knowledge to apply it.
But back to the C-E drive, the small end plate cannot be the same diameter as the inner diameter of the tuning tube. You may try for the same size but it won't move if it is wedged in tightly and you want it to move. What is your expected tolerance on the two diameters? Millimetres? Hundreds of micrometers? Tens of micrometers? Evanescent waves will escape through this gap and we want to see them.
I'm looking at about a .0125mm gap. I've ordered 2 plates. The second one I'll modify for evanescent wave actions with a set pattern in the silver for just them and set a conductive seal between the plate and sidewalls. I just would like to see what meep does in the modes with the antennas you selected and not too worried about them this run.
Is that ok ?
Shell
Shell, is your favorite target mode still TE012? If yes the field strength(E) for this mode tend to zero near the "edge" of frustum and endplate. It is zero in the corner. There will be also no current flow between the frustum and the plate.
So if the gap is small its not "visible" from the viewpoint of this mode.
For some other mode shapes the gap can work as a slot antenna, it can radiate, not in the sense of evanescent waves.. The most interesting point is the length of the slot and thats the circumference in your case(not only the width of the gap is important).
It's easier to model in meep if it's treated as connected or a small gap which aero likes, in real life I'm going around the circumference of the plate with a beryllium copper gasket that will electrically connect to the frustum and seal the endcap but allow it to slide freely.
Shell
Good catch shell, of course...looks like my estimate doubled to about $400K total not including building.So, been thinking about a suitable lab in case further experimentation on NSF-1701 is desired. Here's a stream of consciousness list of the test gear I'd like to get my hands on (all calibrated with computer interface, RF stuff 3 GHz minimum):Tools to make advanced frustums wrt machine shop tools.
(...)OK, what are we missing...hmmm
<edit> I stopped counting at $100,000
So about the same capital cost as a gas station, plus say $250K a year in salaries and another $100K in materials/misc. So around $1m and two years for a useful prototype (if such a thing is even possible). That's a large grant or an average sized early stage venture capital project. Doable, but difficult. At around 200N/Kwh you're approaching the output of a turbojet, that's certainly interesting if it can be achieved. Also, um if the drive doesn't pan out is there any chance the research could lead to a better way to cook a potato?
For venture capital my gut is telling me that you'd need thrust outside of the noise range, say 1N and some indication that better can be reached. A working theory that does not violate CoE or CoM would also be helpful, as would some press releases before seeking funding.
It is way, way too early to start jumping to conclusions. Anyone who does is not being fair. Until open and replicated experimental data is available, it's all noise as far as I'm concerned. As matters stand, there is nothing that is open and replicated.
The ironclad test is a space test. This cannot readily be fooled with artifacts. What's required for that is twin units in reasonably close proximity, one powered and one not, and in all other respects identical.
I know I'm a broken record, but IMHO there are many more uncontrollable factors in low earth orbit than in the lab, considering the minscule power available for the thruster on a cubesat.
TE012 excitation
For the new dimensions you provided I get a very good TE013 excitation at 2.47 GHz, according to TT's spreadsheet.
This is for flat ends. Do you plan flat or spherical ends?External magnetron coupled to 4 loops internally at H plane 180 phase shifted […] And two additional and equal length but added lambda/4 for a 90 phase shift for a total of 180 deg on each. Quad loops ~1/5 WL 10 gauge copper loops excited in the H plane supported by the vertical tuning quartz rod.Could you post a drawing showing the antennas shape and placement?
NSF-1701 update - Last night, I finished the test stand and discovered that the beam support wire stabilized the vertical oscillation so well that I have no need for the oil bath dampener. This lowers the overall weight of the assembly and simplifies it. The laser is end-mounted, throwing about 20 feet to the target. There is significant dispersion, but small interference patterns from the panoramic mirrow reflector generates small dot patterns that I can use to calibrate. 1 gram throws it off the target. 500 mg is full target vertical travel. While this will not show resolution of 1 mg, anything over that should be readable. Approximately 20 mg will equate to 200 millinewtons of force. Anything smaller than that is not practical for any home-builder IMHO. So...the galinstan arrived and it is ready to go. But I have a weekend to enjoy first ;)
Have a favor to ask my NSF pals here...on my 2 hour guest appearance next Thursday/Friday on the digital radio show, the last hour is being left open for callers questions/comments. Rather than the general audience, I'd like NSF folks to call in. It will be fun to hear your voices and get your perspective on the concept/project whether for or against the theories out there. Also a chance to update on your own project (see-shell) ;)
Date is 8/28, call in time about 1:00 AM Pacific Daylight Time 08:00 UTC
Phone No.: (505) 796-8802
Skype: enterprisemission
Should be fun...first names or NSF nicknames only are cool.
I was surprised as well. My guess is the rigid steel wire is doing most the work, plus there is about twice the mass on the knife edges. Verticle dampening is quick, horizontal dampening takes more than twice the time, but has improved. Random airflow does not affect it as much due to the increased mass i believe. This was a real problem before. Verticle dampening of 1 g weight insertion is less than 30 seconds and almost no jitter.NSF-1701 update - Last night, I finished the test stand and discovered that the beam support wire stabilized the vertical oscillation so well that I have no need for the oil bath dampener. This lowers the overall weight of the assembly and simplifies it. The laser is end-mounted, throwing about 20 feet to the target. There is significant dispersion, but small interference patterns from the panoramic mirrow reflector generates small dot patterns that I can use to calibrate. 1 gram throws it off the target. 500 mg is full target vertical travel. While this will not show resolution of 1 mg, anything over that should be readable. Approximately 20 mg will equate to 200 millinewtons of force. Anything smaller than that is not practical for any home-builder IMHO. So...the galinstan arrived and it is ready to go. But I have a weekend to enjoy first ;)
I'm not clear as to whether you are referring to the fact that right now you have succeeded to eliminate all drafts, air convection from your garage so that the beam is stable and the beam does not oscillate on its own or whether you are referring to damping an impulse response. How fast does it damp out an impulse? If there is enough friction so that it damps out the initial impulse response resulting for example from applying an extra weight, you are OK. On the other hand if it does not damp out an initial impulse, you may still need the oil damper.
NSF-1701 update - Last night, I finished the test stand and discovered that the beam support wire stabilized the vertical oscillation so well that I have no need for the oil bath dampener. This lowers the overall weight of the assembly and simplifies it. The laser is end-mounted, throwing about 20 feet to the target. There is significant dispersion, but small interference patterns from the panoramic mirrow reflector generates small dot patterns that I can use to calibrate. 1 gram throws it off the target. 500 mg is full target vertical travel. While this will not show resolution of 1 mg, anything over that should be readable. Approximately 20 mg will equate to 200 millinewtons of force. Anything smaller than that is not practical for any home-builder IMHO. So...the galinstan arrived and it is ready to go. But I have a weekend to enjoy first ;)You have me excited rfmwguy! It will be interesting to compare the two tests as we eneded up with similar setups.
Woosie. ;) Get some coffee and make it so. I'm going to be calling in.Have a favor to ask my NSF pals here...on my 2 hour guest appearance next Thursday/Friday on the digital radio show, the last hour is being left open for callers questions/comments. Rather than the general audience, I'd like NSF folks to call in. It will be fun to hear your voices and get your perspective on the concept/project whether for or against the theories out there. Also a chance to update on your own project (see-shell) ;)
Date is 8/28, call in time about 1:00 AM Pacific Daylight Time 08:00 UTC
Phone No.: (505) 796-8802
Skype: enterprisemission
Should be fun...first names or NSF nicknames only are cool.
(gulp) that's 4AM eastern - might try to do it anyway :)
Yes, I tried that but it attenuated more than focused...I'm still going to play around with it tho. Biggest detriment I see so far is reflective mirror injects junk into beam since its not perfect surface. Not going to invest in lab quality optics, however...NSF-1701 update - Last night, I finished the test stand and discovered that the beam support wire stabilized the vertical oscillation so well that I have no need for the oil bath dampener. This lowers the overall weight of the assembly and simplifies it. The laser is end-mounted, throwing about 20 feet to the target. There is significant dispersion, but small interference patterns from the panoramic mirrow reflector generates small dot patterns that I can use to calibrate. 1 gram throws it off the target. 500 mg is full target vertical travel. While this will not show resolution of 1 mg, anything over that should be readable. Approximately 20 mg will equate to 200 millinewtons of force. Anything smaller than that is not practical for any home-builder IMHO. So...the galinstan arrived and it is ready to go. But I have a weekend to enjoy first ;)You have me excited rfmwguy! It will be interesting to compare the two tests as we eneded up with similar setups.
Did I mention to you that you could make a tiny pinhole in a plastic business card with a hot pin (cheap and dirty pinhole lens) and put it in front of the laser to clean up the beam to get you a very small dot? I was surprised at how well this old school pinhole lens worked.
Shell
Full steam ahead rfmwguy!
...Yes, I tried that but it attenuated more than focused...I'm still going to play around with it tho. Biggest detriment I see so far is reflective mirror injects junk into beam since its not perfect surface. Not going to invest in lab quality optics, however...Where will be the RF feed located in your first test? Will the magnetron be located near the big base or the small base of the truncated cone cavity? (sorry for my poor recollection if you already answered this, and thanks in advance for taking the time to answer it again in that case)
NSF-1701 update - Last night, I finished the test stand and discovered that the beam support wire stabilized the vertical oscillation so well that I have no need for the oil bath dampener. This lowers the overall weight of the assembly and simplifies it. The laser is end-mounted, throwing about 20 feet to the target. There is significant dispersion, but small interference patterns from the panoramic mirrow reflector generates small dot patterns that I can use to calibrate. 1 gram throws it off the target. 500 mg is full target vertical travel. While this will not show resolution of 1 mg, anything over that should be readable. Approximately 20 mg will equate to 200 millinewtons of force. Anything smaller than that is not practical for any home-builder IMHO. So...the galinstan arrived and it is ready to go. But I have a weekend to enjoy first ;)
I like this article a lot! Has some info that I suspected could happen and have been looking for.
In the above article, the mode coupling theory shows how a bended circular
waveguide transforms a TE01 mode into a TM11 mode.
Of course, always will be spurious modes in the process.
My questions are about :
1- By temporal reverse symmetry , the same bended pipe can transform both TE into TM and TM into TE modes?
2-By Parity/mirror symmetry, if one cuts the same converter at it's half lenght and close one of the ends with the same metal of the waveguide, then if one inject a TE mode at the other open end, one gets a TM reflected mode?
TE012 excitation
For the new dimensions you provided I get a very good TE013 excitation at 2.47 GHz, according to TT's spreadsheet.
This is for flat ends. Do you plan flat or spherical ends?External magnetron coupled to 4 loops internally at H plane 180 phase shifted […] And two additional and equal length but added lambda/4 for a 90 phase shift for a total of 180 deg on each. Quad loops ~1/5 WL 10 gauge copper loops excited in the H plane supported by the vertical tuning quartz rod.Could you post a drawing showing the antennas shape and placement?
TE012 excitation
For the new dimensions you provided I get a very good TE013 excitation at 2.47 GHz, according to TT's spreadsheet.
This is for flat ends. Do you plan flat or spherical ends?External magnetron coupled to 4 loops internally at H plane 180 phase shifted […] And two additional and equal length but added lambda/4 for a 90 phase shift for a total of 180 deg on each. Quad loops ~1/5 WL 10 gauge copper loops excited in the H plane supported by the vertical tuning quartz rod.Could you post a drawing showing the antennas shape and placement?
Shell, my understanding from numerous posts is that you are looking at getting TE012 resonance with this design. Please notice that you are NOT going to get TE012 resonance with your proposed dimensions. Flux Capacitor gets TE013 resonance instead. I don't get TE012 resonance at 2.45 GHz either, far away from it
Using:
bigDiameter = 0.295(*meter*); smallDiameter = 0.160(*meter*); axialLength = 0.2574(*meter*);
assuming flat ends
I get this cone half-angle:
theta=14.69 degrees
and these resonances:
TE012 =2.033 GHz
TE013 =2.418 GHz with a Q = 83,300
Note:
a) there is no way it can resonate at 2.45 GHz in TE012, the resonance for TE012 is 2.03 GHz which is very far away.
b) even TE013 resonates a frequency below 2.45GHz, it resonates at 2.42 GHz.
c) using the extension, extending the length, will make it even more difficult to resonate in TE013. Remember than longer length lower the natural frequencies of given mode shapes
d) you have to make the EM Drive shorter
////////////////////////////////////////////
Decreasing the length to 0.163 meters results in:
bigDiameter = 0.295(*meter*); smallDiameter = 0.160(*meter*); axialLength = 0.163(*meter*);
assuming flat ends
I get this cone half-angle:
theta = 22.50 degrees
and these resonances:
TE012 = 2.450 GHz Q = 73,800
TE013 = 3.152 GHz Q= 70,000
Actually, you would be well advised to make the length somewhat smaller than 0.163 meters, so that you can tune it with the longer length of the cylindrical extension.
Remember that using the cylindrical extension to increase the length of the cavity, will lower the natural frequencies of given mode shapes
Dr. Rodal -
Thanks very much for you post #812, which explained much pertaining to out previous discussion.
Of your logic, the only remaining thing I don't understand is why the side wall force must always be a pressure in TE modes. If I'm understanding the pictures Aero has shared, for what I think was TE012, the magnetic field is unidirectional, and the electric field circulates in the frustrum in opposite directions in the small and big end (halves) respectively. The wall force direction looks to me opposite in each half, and why it should always integrate to a net pressure escapes me.
I don't seriously doubt that you are correct but I for one, and I would guess others, would really appreciate your insight into why this is so.
Regards and thanks in advance,
R.
The force distributions are plotted below, for the lowest n value and lowest three k values for the TE mode(s). This time there is no Coulomb tension, so the pressure is the only contribution to the force.(bold added for emphasis, parenthesis (s) added for clarity)
Yes right! I getTE012 excitation
For the new dimensions you provided I get a very good TE013 excitation at 2.47 GHz, according to TT's spreadsheet.
This is for flat ends. Do you plan flat or spherical ends?External magnetron coupled to 4 loops internally at H plane 180 phase shifted […] And two additional and equal length but added lambda/4 for a 90 phase shift for a total of 180 deg on each. Quad loops ~1/5 WL 10 gauge copper loops excited in the H plane supported by the vertical tuning quartz rod.Could you post a drawing showing the antennas shape and placement?
Shell, my understanding from numerous posts is that you are looking at getting TE012 resonance with this design. Please notice that you are NOT going to get TE012 resonance with your proposed dimensions. Flux Capacitor gets TE013 resonance instead. I don't get TE012 resonance at 2.45 GHz either, far away from it
Using:
bigDiameter = 0.295(*meter*); smallDiameter = 0.160(*meter*); axialLength = 0.2574(*meter*);
assuming flat ends
I get this cone half-angle:
theta=14.69 degrees
and these resonances:
TE012 =2.033 GHz
TE013 =2.418 GHz with a Q = 83,300
Note:
a) there is no way it can resonate at 2.45 GHz in TE012, the resonance for TE012 is 2.03 GHz which is very far away.
b) even TE013 resonates a frequency below 2.45GHz, it resonates at 2.42 GHz.
c) using the extension, extending the length, will make it even more difficult to resonate in TE013. Remember than longer length lower the natural frequencies of given mode shapes
d) you have to make the EM Drive shorter
////////////////////////////////////////////
Decreasing the length to 0.163 meters results in:
bigDiameter = 0.295(*meter*); smallDiameter = 0.160(*meter*); axialLength = 0.163(*meter*);
assuming flat ends
I get this cone half-angle:
theta = 22.50 degrees
and these resonances:
TE012 = 2.450 GHz Q = 73,800
TE013 = 3.152 GHz Q= 70,000
Actually, you would be well advised to make the length somewhat smaller than 0.163 meters, so that you can tune it with the longer length of the cylindrical extension.
Remember that using the cylindrical extension to increase the length of the cavity, will lower the natural frequencies of given mode shapes
Meep does concur.
You get the same results that I do?Yes right! I getTE012 excitation
For the new dimensions you provided I get a very good TE013 excitation at 2.47 GHz, according to TT's spreadsheet.
This is for flat ends. Do you plan flat or spherical ends?External magnetron coupled to 4 loops internally at H plane 180 phase shifted […] And two additional and equal length but added lambda/4 for a 90 phase shift for a total of 180 deg on each. Quad loops ~1/5 WL 10 gauge copper loops excited in the H plane supported by the vertical tuning quartz rod.Could you post a drawing showing the antennas shape and placement?
Shell, my understanding from numerous posts is that you are looking at getting TE012 resonance with this design. Please notice that you are NOT going to get TE012 resonance with your proposed dimensions. Flux Capacitor gets TE013 resonance instead. I don't get TE012 resonance at 2.45 GHz either, far away from it
Using:
bigDiameter = 0.295(*meter*); smallDiameter = 0.160(*meter*); axialLength = 0.2574(*meter*);
assuming flat ends
I get this cone half-angle:
theta=14.69 degrees
and these resonances:
TE012 =2.033 GHz
TE013 =2.418 GHz with a Q = 83,300
Note:
a) there is no way it can resonate at 2.45 GHz in TE012, the resonance for TE012 is 2.03 GHz which is very far away.
b) even TE013 resonates a frequency below 2.45GHz, it resonates at 2.42 GHz.
c) using the extension, extending the length, will make it even more difficult to resonate in TE013. Remember than longer length lower the natural frequencies of given mode shapes
d) you have to make the EM Drive shorter
////////////////////////////////////////////
Decreasing the length to 0.163 meters results in:
bigDiameter = 0.295(*meter*); smallDiameter = 0.160(*meter*); axialLength = 0.163(*meter*);
assuming flat ends
I get this cone half-angle:
theta = 22.50 degrees
and these resonances:
TE012 = 2.450 GHz Q = 73,800
TE013 = 3.152 GHz Q= 70,000
Actually, you would be well advised to make the length somewhat smaller than 0.163 meters, so that you can tune it with the longer length of the cylindrical extension.
Remember that using the cylindrical extension to increase the length of the cavity, will lower the natural frequencies of given mode shapes
TE012: 2,0338837667GHz
TE013:2,4183010112GHz
for the upper dimensions and flat end plates.
As you sad: Double check all numbers! Again and again and so on...
Location is almost identical to EW on small end....Yes, I tried that but it attenuated more than focused...I'm still going to play around with it tho. Biggest detriment I see so far is reflective mirror injects junk into beam since its not perfect surface. Not going to invest in lab quality optics, however...Where will be the RF feed located in your first test? Will the magnetron be located near the big base or the small base of the truncated cone cavity? (sorry for my poor recollection if you already answered this, and thanks in advance for taking the time to answer it again in that case)
I'll do a walkaround video within 24 hrs.NSF-1701 update - Last night, I finished the test stand and discovered that the beam support wire stabilized the vertical oscillation so well that I have no need for the oil bath dampener. This lowers the overall weight of the assembly and simplifies it. The laser is end-mounted, throwing about 20 feet to the target. There is significant dispersion, but small interference patterns from the panoramic mirrow reflector generates small dot patterns that I can use to calibrate. 1 gram throws it off the target. 500 mg is full target vertical travel. While this will not show resolution of 1 mg, anything over that should be readable. Approximately 20 mg will equate to 200 millinewtons of force. Anything smaller than that is not practical for any home-builder IMHO. So...the galinstan arrived and it is ready to go. But I have a weekend to enjoy first ;)
Can you post pictures of your device and rig?
Location is almost identical to EW on small end....Yes, I tried that but it attenuated more than focused...I'm still going to play around with it tho. Biggest detriment I see so far is reflective mirror injects junk into beam since its not perfect surface. Not going to invest in lab quality optics, however...Where will be the RF feed located in your first test? Will the magnetron be located near the big base or the small base of the truncated cone cavity? (sorry for my poor recollection if you already answered this, and thanks in advance for taking the time to answer it again in that case)
For this dimensions YesYou get the same results that I do?Yes right! I getTE012 excitation
For the new dimensions you provided I get a very good TE013 excitation at 2.47 GHz, according to TT's spreadsheet.
This is for flat ends. Do you plan flat or spherical ends?External magnetron coupled to 4 loops internally at H plane 180 phase shifted […] And two additional and equal length but added lambda/4 for a 90 phase shift for a total of 180 deg on each. Quad loops ~1/5 WL 10 gauge copper loops excited in the H plane supported by the vertical tuning quartz rod.Could you post a drawing showing the antennas shape and placement?
Shell, my understanding from numerous posts is that you are looking at getting TE012 resonance with this design. Please notice that you are NOT going to get TE012 resonance with your proposed dimensions. Flux Capacitor gets TE013 resonance instead. I don't get TE012 resonance at 2.45 GHz either, far away from it
Using:
bigDiameter = 0.295(*meter*); smallDiameter = 0.160(*meter*); axialLength = 0.2574(*meter*);
assuming flat ends
I get this cone half-angle:
theta=14.69 degrees
and these resonances:
TE012 =2.033 GHz
TE013 =2.418 GHz with a Q = 83,300
Note:
a) there is no way it can resonate at 2.45 GHz in TE012, the resonance for TE012 is 2.03 GHz which is very far away.
b) even TE013 resonates a frequency below 2.45GHz, it resonates at 2.42 GHz.
c) using the extension, extending the length, will make it even more difficult to resonate in TE013. Remember than longer length lower the natural frequencies of given mode shapes
d) you have to make the EM Drive shorter
////////////////////////////////////////////
Decreasing the length to 0.163 meters results in:
bigDiameter = 0.295(*meter*); smallDiameter = 0.160(*meter*); axialLength = 0.163(*meter*);
assuming flat ends
I get this cone half-angle:
theta = 22.50 degrees
and these resonances:
TE012 = 2.450 GHz Q = 73,800
TE013 = 3.152 GHz Q= 70,000
Actually, you would be well advised to make the length somewhat smaller than 0.163 meters, so that you can tune it with the longer length of the cylindrical extension.
Remember that using the cylindrical extension to increase the length of the cavity, will lower the natural frequencies of given mode shapes
TE012: 2,0338837667GHz
TE013:2,4183010112GHz
for the upper dimensions and flat end plates.
As you sad: Double check all numbers! Again and again and so on...
and way different from TheTraveller's spreadsheet?
You get the same results that I do?Yes right! I getTE012 excitation
For the new dimensions you provided I get a very good TE013 excitation at 2.47 GHz, according to TT's spreadsheet.
This is for flat ends. Do you plan flat or spherical ends?External magnetron coupled to 4 loops internally at H plane 180 phase shifted […] And two additional and equal length but added lambda/4 for a 90 phase shift for a total of 180 deg on each. Quad loops ~1/5 WL 10 gauge copper loops excited in the H plane supported by the vertical tuning quartz rod.Could you post a drawing showing the antennas shape and placement?
Shell, my understanding from numerous posts is that you are looking at getting TE012 resonance with this design. Please notice that you are NOT going to get TE012 resonance with your proposed dimensions. Flux Capacitor gets TE013 resonance instead. I don't get TE012 resonance at 2.45 GHz either, far away from it
Using:
bigDiameter = 0.295(*meter*); smallDiameter = 0.160(*meter*); axialLength = 0.2574(*meter*);
assuming flat ends
I get this cone half-angle:
theta=14.69 degrees
and these resonances:
TE012 =2.033 GHz
TE013 =2.418 GHz with a Q = 83,300
Note:
a) there is no way it can resonate at 2.45 GHz in TE012, the resonance for TE012 is 2.03 GHz which is very far away.
b) even TE013 resonates a frequency below 2.45GHz, it resonates at 2.42 GHz.
c) using the extension, extending the length, will make it even more difficult to resonate in TE013. Remember than longer length lower the natural frequencies of given mode shapes
d) you have to make the EM Drive shorter
////////////////////////////////////////////
Decreasing the length to 0.163 meters results in:
bigDiameter = 0.295(*meter*); smallDiameter = 0.160(*meter*); axialLength = 0.163(*meter*);
assuming flat ends
I get this cone half-angle:
theta = 22.50 degrees
and these resonances:
TE012 = 2.450 GHz Q = 73,800
TE013 = 3.152 GHz Q= 70,000
Actually, you would be well advised to make the length somewhat smaller than 0.163 meters, so that you can tune it with the longer length of the cylindrical extension.
Remember that using the cylindrical extension to increase the length of the cavity, will lower the natural frequencies of given mode shapes
TE012: 2,0338837667GHz
TE013:2,4183010112GHz
for the upper dimensions and flat end plates.
As you sad: Double check all numbers! Again and again and so on...
and way different from TheTraveller's spreadsheet?
Dr. Rodal - Thanks. The Egan page was a cold shower for emdrive optimists, but leaving that aside explains what you have been saying.
His analysis depends on E-Parallel being zero, which is not strictly correct, but it isn't much to cling to!
Regards,
R.
Can you share the download link please. I want to get a look and play withYou get the same results that I do?Yes right! I getTE012 excitation
For the new dimensions you provided I get a very good TE013 excitation at 2.47 GHz, according to TT's spreadsheet.
This is for flat ends. Do you plan flat or spherical ends?External magnetron coupled to 4 loops internally at H plane 180 phase shifted […] And two additional and equal length but added lambda/4 for a 90 phase shift for a total of 180 deg on each. Quad loops ~1/5 WL 10 gauge copper loops excited in the H plane supported by the vertical tuning quartz rod.Could you post a drawing showing the antennas shape and placement?
Shell, my understanding from numerous posts is that you are looking at getting TE012 resonance with this design. Please notice that you are NOT going to get TE012 resonance with your proposed dimensions. Flux Capacitor gets TE013 resonance instead. I don't get TE012 resonance at 2.45 GHz either, far away from it
Using:
bigDiameter = 0.295(*meter*); smallDiameter = 0.160(*meter*); axialLength = 0.2574(*meter*);
assuming flat ends
I get this cone half-angle:
theta=14.69 degrees
and these resonances:
TE012 =2.033 GHz
TE013 =2.418 GHz with a Q = 83,300
Note:
a) there is no way it can resonate at 2.45 GHz in TE012, the resonance for TE012 is 2.03 GHz which is very far away.
b) even TE013 resonates a frequency below 2.45GHz, it resonates at 2.42 GHz.
c) using the extension, extending the length, will make it even more difficult to resonate in TE013. Remember than longer length lower the natural frequencies of given mode shapes
d) you have to make the EM Drive shorter
////////////////////////////////////////////
Decreasing the length to 0.163 meters results in:
bigDiameter = 0.295(*meter*); smallDiameter = 0.160(*meter*); axialLength = 0.163(*meter*);
assuming flat ends
I get this cone half-angle:
theta = 22.50 degrees
and these resonances:
TE012 = 2.450 GHz Q = 73,800
TE013 = 3.152 GHz Q= 70,000
Actually, you would be well advised to make the length somewhat smaller than 0.163 meters, so that you can tune it with the longer length of the cylindrical extension.
Remember that using the cylindrical extension to increase the length of the cavity, will lower the natural frequencies of given mode shapes
TE012: 2,0338837667GHz
TE013:2,4183010112GHz
for the upper dimensions and flat end plates.
As you sad: Double check all numbers! Again and again and so on...
and way different from TheTraveller's spreadsheet?
I trying the Travelers Spread sheet I just downloaded, it's a little confusing on his settings as to what's happening and what to select. It seems to want to bomb when I select mode TE12 from his chart. Anyone care to try it, just don't have enough time playing around with it I guess.
For this dimensions Yes
bigDiameter = 0.295(*meter*); smallDiameter = 0.160(*meter*); axialLength = 0.2574(*meter*);
assuming flat ends
theta=14,6942464607
For TE013 and a lenght of 262mm i get 2,3960911146GHz theta=14,4471°For this dimensions Yes
bigDiameter = 0.295(*meter*); smallDiameter = 0.160(*meter*); axialLength = 0.2574(*meter*);
assuming flat ends
theta=14,6942464607
My Length was different as I didn't know See-Shells would use a cylindrical neck extension.
I assumed L = 0.262 m (and a half-cone angle of 14.45°) and c in ambient air, while you use 0.2574 m and c in vac.
I indeed found for L = 0.262 m a TE013 resonance at 2.47 GHz using c in ambient air, with TT's spreadsheet.
It is my understanding that SeeShells will use the length of 0.2574 m to build the frustum: it is the vertical length between the big base and the small end while the small end is at minimal extension into the cylindrical neck. But the final length between plates once tuned will be actually longer, as the small base will be recessed into the cylindrical extension (the distance plate to plate was set to be 0.262 m)
The spreadsheet cannot handle shapes with a cylinder extension added to a conical portion. In this case the distance between plates is longer but the cone angle is kept the same.
There was a coupling loop on an EW pic behind the HDPE. It was abt 3.5 cm from edge, which is where mine is.Location is almost identical to EW on small end....Yes, I tried that but it attenuated more than focused...I'm still going to play around with it tho. Biggest detriment I see so far is reflective mirror injects junk into beam since its not perfect surface. Not going to invest in lab quality optics, however...Where will be the RF feed located in your first test? Will the magnetron be located near the big base or the small base of the truncated cone cavity? (sorry for my poor recollection if you already answered this, and thanks in advance for taking the time to answer it again in that case)
NASA Eagleworks has the RF feed at the Big End for their reported experiment. They cannot have the RF feed at the small end because the dielectric insert (HDPE) is located at the small end.
Please clarify whether you made a typo and you meant to write that you have it at the big end or whether you do have it at the small end, perhaps based on the proposal (not yet tested) by Paul March to have an EM Drive without a dielectric insert, with a magnetron at the small end tested in a teeter-totter instead of a the torque balance, as in this drawing:
(http://forum.nasaspaceflight.com/xindex.php,qaction=dlattach,3Btopic=38203.0,3Battach=1058904,3Bimage.pagespeed.ic.vM_8dbeSSw.webp)
Thanks
Meep does concur.
How does that stack up with the known output of the magnetron? Is there a good reason to test in TE012 and not TE013?
NSF-1701 update - Last night, I finished the test stand and discovered that the beam support wire stabilized the vertical oscillation so well that I have no need for the oil bath dampener. This lowers the overall weight of the assembly and simplifies it. The laser is end-mounted, throwing about 20 feet to the target. There is significant dispersion, but small interference patterns from the panoramic mirrow reflector generates small dot patterns that I can use to calibrate. 1 gram throws it off the target. 500 mg is full target vertical travel. While this will not show resolution of 1 mg, anything over that should be readable. Approximately 20 mg will equate to 200 millinewtons of force. Anything smaller than that is not practical for any home-builder IMHO. So...the galinstan arrived and it is ready to go. But I have a weekend to enjoy first ;)
I trying the Travelers Spread sheet I just downloaded, it's a little confusing on his settings as to what's happening and what to select. It seems to want to bomb when I select mode TE12 from his chart. Anyone care to try it, just don't have enough time playing around with it I guess.
Shell
Added
On another note my magnetron center frequency is stable at 2.47GHz
That's the one with lots of duplication of the same value, isn't it? If I had the energy I'd rip it up and redesign it
If 1N/kW could be proven, every aerospace company on the planet would be building these. Yes, it's that big a game-changer. Mind you, if I understand the physics correctly, a 100% efficient unit would be 1KN/KW right? That means currently we're only talking about a 0.1% efficiency (1N) and that would be enough to change the face of spaceflight. Figure this thing out and the money will come at you like a firehose (my conjecture).
X_RayI think that's not for FLAT end plates...
Wiki page
http://emdrive.wiki/Useful_EMDrive_Design_and_Test_Tools
Look, go easy on the guy. He doesn't have the first clue about the physics of it. He just wants to be involved. You know, emotionally. 8)If 1N/kW could be proven, every aerospace company on the planet would be building these. Yes, it's that big a game-changer. Mind you, if I understand the physics correctly, a 100% efficient unit would be 1KN/KW right? That means currently we're only talking about a 0.1% efficiency (1N) and that would be enough to change the face of spaceflight. Figure this thing out and the money will come at you like a firehose (my conjecture).
I fail to see what is the relation between 1kN and 1kW that would make 1kN/kW "100% efficient". In SI units N is kg*m/s² and W is kg*m²/s3, the ratio of N/W is the inverse of a velocity in m/s. Saying that 1kN/kW is anything special is saying that 1m/s is a special speed, while the meter and the second (and hence the speed 1 m/s) are not natural units in any respect.
On the other hand 3.33*10-9N/W is a special value since it is the inverse of the very special natural speed c, and it is the natural limit of propulsion efficiency for anything that is "self fed" and self powered in deep space (i.e. not relying on incoming mass or energy flow or nearby objects field) if one includes the energy equivalent of spent mass in the case of classical action-reaction (chemical rocket, ion thruster...).
100% efficiency is 3.33*10-9N/W, above that is above 100% and leads to apparent overunity (energy wise). And this is not sounding like a broken record, more like time invariance of reality.
Do you get the spreadsheet on the wiki? I modified the link so you can download it again, because it seems TheTraveller denied access to his Gdrive and deleted all his messages posted on NSF in the last 6 days (as well as his Reddit account) :-\Bruised sensitivities? If it happened here, I surely missed it.
The new URL:
https://www.dropbox.com/s/u6v90c5yb050u52/EMDriveCalc20150809a.xlsx?dl=1 (https://www.dropbox.com/s/u6v90c5yb050u52/EMDriveCalc20150809a.xlsx?dl=1)
Yes, I tried that but it attenuated more than focused...I'm still going to play around with it tho. Biggest detriment I see so far is reflective mirror injects junk into beam since its not perfect surface. Not going to invest in lab quality optics, however...
I updated the screenshot at http://emdrive.wiki/Useful_EMDrive_Design_and_Test_ToolsOK, thank's
and added captions to show how to use the spreadsheet.
I think that's not for FLAT end plates...
If i change the value for "spherical" it make no difference.
(red text)
@TT: What is a "SPR adj Factor"?
PS: yes i have to press the enter button after changing a value in libre office :-[Ok then, I was afraid of some worse incompatibility :)
Fig 7 and 15 in NASA's reportThere was a coupling loop on an EW pic behind the HDPE. It was abt 3.5 cm from edge, which is where mine is.Location is almost identical to EW on small end....Yes, I tried that but it attenuated more than focused...I'm still going to play around with it tho. Biggest detriment I see so far is reflective mirror injects junk into beam since its not perfect surface. Not going to invest in lab quality optics, however...Where will be the RF feed located in your first test? Will the magnetron be located near the big base or the small base of the truncated cone cavity? (sorry for my poor recollection if you already answered this, and thanks in advance for taking the time to answer it again in that case)
NASA Eagleworks has the RF feed at the Big End for their reported experiment. They cannot have the RF feed at the small end because the dielectric insert (HDPE) is located at the small end.
Please clarify whether you made a typo and you meant to write that you have it at the big end or whether you do have it at the small end, perhaps based on the proposal (not yet tested) by Paul March to have an EM Drive without a dielectric insert, with a magnetron at the small end tested in a teeter-totter instead of a the torque balance, as in this drawing:
(http://forum.nasaspaceflight.com/xindex.php,qaction=dlattach,3Btopic=38203.0,3Battach=1058904,3Bimage.pagespeed.ic.vM_8dbeSSw.webp)
Thanks
Dr. Rodal -
When I refer to "E-Parallel=0" I mean the generally accepted boundary condition that the electric field parallel to the surface of a conductor is zero. He uses this everywhere.
In fact, it is only an approximation, akin to electrons having zero mass. In fact, Electrons (must surely) take a small amount of time to accelerate and react to imposed fields.
However, the time is very short, and it really isn't much to cling to.
While I'm here, a pure maths nit on his paper would be that he has not shown that TE and TM are the only solutions, only that they are solutions.
R.
Please save us time on this. WikiP reports delta-c/c <= 10-17 from the most recent measurements. Is this the value taken by your two guys?
viXra is just about the last place to go for "information", btw.
OK, I peeked. This from arXiv critiques your sources
http://arxiv.org/abs/1404.6095
Diurnal and seasonal variations in CO2 is the likely culprit.
There was a coupling loop on an EW pic behind the HDPE. It was abt 3.5 cm from edge, which is where mine is.
Do you get the spreadsheet on the wiki? I modified the link so you can download it again, because it seems TheTraveller denied access to his Gdrive and deleted all his messages posted on NSF in the last 6 days (as well as his Reddit account) :-\
The new URL:
https://www.dropbox.com/s/u6v90c5yb050u52/EMDriveCalc20150809a.xlsx?dl=1 (https://www.dropbox.com/s/u6v90c5yb050u52/EMDriveCalc20150809a.xlsx?dl=1)
Yeah indications are that TT walked away. I don't know what all happened over on our sister thread, but the end result is we lost a valuable ally in the fight.
[TheTraveller] apparently didn't deleted his profile on NSF, but he apparently deleted all his posts on NSF from the last 6 days :(
I know he is continuously downvoted for his public behavior, but we need to keep in mind several things with TheTraveller:
1. He is the only one who has a direct connection to Roger Shawyer.
2. He made an Excel spreadsheet publicly available to calculate frustum dimensions and resonant modes, excellent for DIYers.
3. He is the only one planning an experiment where all the electronics and batteries, besides the EmDrive, are self-contained within a rotary test rig. Everyone else is planning scale or fulcrum tests with 1) external power supplies and 2) with limited acceleration due to very short distance, which makes TT's experiment unique and extremely valuable.
4. He has some knowledge and connections for building precise solid copper frustums from high speed metal lathe spinning, including spherical end plates, while everyone else is making their flat ends copper frustum from metallic meshes or copper sheets joined with tin and welded torches.
5. As an engineer he worked before on software and hardware feedback control loop systems. Now he is currently developing such a system for his EmDrive that will maintain a center resonant frequency while his cavity detunes.
6. He is planning to make a small series production of his test rig that can be shipped to any lab for IV&V
7. He is spending $20K out of his pocket to do so. I don't argue about his own money or crowd-funding money which is perfectly fine for me (please support See-Shell (http://www.gofundme.com/yy7yz3k) also!) but the sum of money is impressive and should lead to a very qualitative build on par with Boeing's Flight Thruster designed by SPR.
8. And I'm sorry to say that, he may not have the time he needs due to his serious disease. That's why he may be overly impatient and irascible. I'm not excusing his behavior (I don't like how he talks to other people) but I keep thinking about all other points above.
So yes, his leaving is unfortunate. I hope he will return at last on NSF to present the results of his test rig.
That is really a shame. It wasn't always enjoyable wading through the fanaticism, which kept strumming the chord in me "this stance is antithesis of the scientific process", but his input was often insightful, and his contributions many.Do you get the spreadsheet on the wiki? I modified the link so you can download it again, because it seems TheTraveller denied access to his Gdrive and deleted all his messages posted on NSF in the last 6 days (as well as his Reddit account) :-\
The new URL:
https://www.dropbox.com/s/u6v90c5yb050u52/EMDriveCalc20150809a.xlsx?dl=1 (https://www.dropbox.com/s/u6v90c5yb050u52/EMDriveCalc20150809a.xlsx?dl=1)
Yeah indications are that TT walked away. I don't know what all happened over on our sister thread, but the end result is we lost a valuable ally in the fight.
Got it Thanks! That makes more sense. I just went back and indeed he locked out the sheet. How childish.I updated the screenshot at http://emdrive.wiki/Useful_EMDrive_Design_and_Test_ToolsOK, thank's
and added captions to show how to use the spreadsheet.
PS: yes i have to press the enter button after changing a value in libre office :-[
it's midnight in germany, enough for today..
Do you get the spreadsheet on the wiki? I modified the link so you can download it again, because it seems TheTraveller denied access to his Gdrive and deleted all his messages posted on NSF in the last 6 days (as well as his Reddit account) :-\Bruised sensitivities? If it happened here, I surely missed it.
The new URL:
https://www.dropbox.com/s/u6v90c5yb050u52/EMDriveCalc20150809a.xlsx?dl=1 (https://www.dropbox.com/s/u6v90c5yb050u52/EMDriveCalc20150809a.xlsx?dl=1)
OH, hang on. Might this have been a tantrum occasioned by the dissection of the SPR financials?
Let's shrink it up areo! My mistake let's do the TE012 right this time using Dr. Rodals and X_Ray's lengths @ 163mm, keep the top circular tube @ 100mm and the same insertion depth as before. Let Harmiv calculate the resonate frequency and Q.Meep does concur.
How does that stack up with the known output of the magnetron? Is there a good reason to test in TE012 and not TE013?
I didn't get the bandwidth reduced to realistic values so the noisy source I used had over 10 times the realistic bandwdith. Resonated at about 2.426 GHz, I can't verify the mode. So meep didn't really give us much information in this case.
As head strong as he was, I'll still say yes. There is no bad data.Do you get the spreadsheet on the wiki? I modified the link so you can download it again, because it seems TheTraveller denied access to his Gdrive and deleted all his messages posted on NSF in the last 6 days (as well as his Reddit account) :-\
The new URL:
https://www.dropbox.com/s/u6v90c5yb050u52/EMDriveCalc20150809a.xlsx?dl=1 (https://www.dropbox.com/s/u6v90c5yb050u52/EMDriveCalc20150809a.xlsx?dl=1)
Yeah indications are that TT walked away. I don't know what all happened over on our sister thread, but the end result is we lost a valuable ally in the fight.
http://ir.hfcas.ac.cn/bitstream/334002/12022/1/
Mode%20converters%20for%20generating%20the
%20HE%2011%20%28gaussian%20like%29%20mode
%20from%20TE%2001%20in%20a%20circular%20waveguide.pdf
In the above article, the mode coupling theory shows how a bended circular waveguide transforms a TE01 mode into a TM11 mode.
Of course, always will be spurious modes in the process.
My questions are about :
1- By temporal reverse symmetry , the same bended pipe can transform both TE into TM and TM into TE modes?
2-By Parity/mirror symmetry, if one cuts the same converter at it's half lenght and close one of the ends with the same metal of the waveguide, then if one inject a TE mode at the other open end, one gets a TM reflected mode?
Please save us time on this. WikiP reports delta-c/c <= 10-17 from the most recent measurements. Is this the value taken by your two guys?
viXra is just about the last place to go for "information", btw.
OK, I peeked. This from arXiv critiques your sources
http://arxiv.org/abs/1404.6095
Diurnal and seasonal variations in CO2 is the likely culprit.
Well I'm certainly not interested in citing vixra trying to overthrow consensus. But I am also obliged to think differently nowadays because of this silly copper can. It is interesting reading nonetheless.
I fully ascribe to the fact that there are no preferred reference frames. At the same time, I'm seeing tantalizing clues that it may be possible to artificially create a preferred reference frame. Think back to the "laser through the resonant cavity" experiment * reported by Star-Drive and the magnetoelectric anisotropy in air experiment I linked to so many times.
The common theme there anisotropy in the speed of light in a medium while under external electromagnetic fields.
So if you have an experiment that shows the speed of light is different going forward as opposed to coming back, where is the preferred frame? Does that by definition set a preferred frame? I'm not sure. This is where all this Aether stuff comes in, as some believe the Aether is either partially or completely entrained by matter. If indeed it is found to be possible to create a preferred reference frame, is that going to ruin everyone's day?
I want to make sure people understand that when I say Aether, I'm not referring to the Luminiferous Aether. I mean the one where there is no concept of motion.
Curious to note, that within the EmDrive's tapered cavity, we have a varying group velocity from fore to aft. Same for phase velocity.** But if you flip the whole thing over, there is symmetry.
With the EmDrive in mind here, and just for S&G's here, assuming that if such a Relativistic Aether exists and that the electromagnetic component (what we call the electromagnetic vacuum) of that Aether must obey the same laws as the real electromagnetic component, did an artificial preferred frame get created in there?
Is breaking the symmetry of a simple cylindrical resonator enough to do this? I don't think so. I've been looking for a parity violation of in an empty copper can for months now and I can't find it. The closest thing that even resembles handedness would be the counter rotating E fields as seen in the TE012 Comsol plot from Eagleworks.
* All I can do is take their word that they ruled out the obvious like refractive index, heating...etc
** http://www.microwaves101.com/encyclopedias/light-phase-and-group-velocities (bottom two equations)
For me, what is important here, and pretty much my entire focus is (trusting all the experiments completed to date aren't all flawed) figuring out how momentum is conserved. We spend a lot of time here creating valuable data and analysis, but I choose to sit out most of that because I view those as optimizations.
I don't think we'll make much progress unless the physics is found first. I would honestly walk away from this whole thing if I knew that the pros from academia were on it. This EmDrive is such a hot potato apparently, that only a dirty dozen or so even really cares.
Let's shrink it up areo! My mistake let's do the TE012 right this time using Dr. Rodals and X_Ray's lengths @ 163mm, keep the top circular tube @ 100mm and the same insertion depth as before. Let Harmiv calculate the resonate frequency and Q.Meep does concur.
How does that stack up with the known output of the magnetron? Is there a good reason to test in TE012 and not TE013?
I didn't get the bandwidth reduced to realistic values so the noisy source I used had over 10 times the realistic bandwdith. Resonated at about 2.426 GHz, I can't verify the mode. So meep didn't really give us much information in this case.
I'll be interested how this mode looks with this short of length.
This ok? Thanks Areo!
Shell
If 1N/kW could be proven, every aerospace company on the planet would be building these. Yes, it's that big a game-changer. Mind you, if I understand the physics correctly, a 100% efficient unit would be 1KN/KW right? That means currently we're only talking about a 0.1% efficiency (1N) and that would be enough to change the face of spaceflight. Figure this thing out and the money will come at you like a firehose (my conjecture).
Yes drop the bottom and top down to your sidewall line and that will truly come close to what I should end up with.Let's shrink it up areo! My mistake let's do the TE012 right this time using Dr. Rodals and X_Ray's lengths @ 163mm, keep the top circular tube @ 100mm and the same insertion depth as before. Let Harmiv calculate the resonate frequency and Q.Meep does concur.
How does that stack up with the known output of the magnetron? Is there a good reason to test in TE012 and not TE013?
I didn't get the bandwidth reduced to realistic values so the noisy source I used had over 10 times the realistic bandwdith. Resonated at about 2.426 GHz, I can't verify the mode. So meep didn't really give us much information in this case.
I'll be interested how this mode looks with this short of length.
This ok? Thanks Areo!
Shell
Like this? It looks lop-sided to me but I can't guess why. Can you?
Let's shrink it up areo! My mistake let's do the TE012 right this time using Dr. Rodals and X_Ray's lengths @ 163mm, keep the top circular tube @ 100mm and the same insertion depth as before. Let Harmiv calculate the resonate frequency and Q.Meep does concur.
How does that stack up with the known output of the magnetron? Is there a good reason to test in TE012 and not TE013?
I didn't get the bandwidth reduced to realistic values so the noisy source I used had over 10 times the realistic bandwdith. Resonated at about 2.426 GHz, I can't verify the mode. So meep didn't really give us much information in this case.
I'll be interested how this mode looks with this short of length.
This ok? Thanks Areo!
Shell
Like this? It looks lop-sided to me but I can't guess why. Can you?
It looks like the same position as in the last run for Yang. This is really squeezed down with the the base plate size almost the same as the distance between the plates.Let's shrink it up areo! My mistake let's do the TE012 right this time using Dr. Rodals and X_Ray's lengths @ 163mm, keep the top circular tube @ 100mm and the same insertion depth as before. Let Harmiv calculate the resonate frequency and Q.Meep does concur.
How does that stack up with the known output of the magnetron? Is there a good reason to test in TE012 and not TE013?
I didn't get the bandwidth reduced to realistic values so the noisy source I used had over 10 times the realistic bandwdith. Resonated at about 2.426 GHz, I can't verify the mode. So meep didn't really give us much information in this case.
I'll be interested how this mode looks with this short of length.
This ok? Thanks Areo!
Shell
Like this? It looks lop-sided to me but I can't guess why. Can you?
The antenna should be closer to the big base. How are you coming up with that distance?
It looks like the same position as in the last run for Yang. This is really squeezed down with the the base plate size almost the same as the distance between the plates.Let's shrink it up areo! My mistake let's do the TE012 right this time using Dr. Rodals and X_Ray's lengths @ 163mm, keep the top circular tube @ 100mm and the same insertion depth as before. Let Harmiv calculate the resonate frequency and Q.Meep does concur.
How does that stack up with the known output of the magnetron? Is there a good reason to test in TE012 and not TE013?
I didn't get the bandwidth reduced to realistic values so the noisy source I used had over 10 times the realistic bandwdith. Resonated at about 2.426 GHz, I can't verify the mode. So meep didn't really give us much information in this case.
I'll be interested how this mode looks with this short of length.
This ok? Thanks Areo!
Shell
Like this? It looks lop-sided to me but I can't guess why. Can you?
The antenna should be closer to the big base. How are you coming up with that distance?
Too early for a failed test, I believe. It might also be that Shawyer has put the squeeze on him and taken him private.
It's a great shame if he's walked, because (with no disrespect intended to other heroic DIYers) he had the best damn experimental design I've yet seen. I hope he reconsiders. I also hope he can beat that disease.
Too early for a failed test, I believe. It might also be that Shawyer has put the squeeze on him and taken him private.
It's a great shame if he's walked, because (with no disrespect intended to other heroic DIYers) he had the best damn experimental design I've yet seen. I hope he reconsiders. I also hope he can beat that disease.
Could have been Shawyer and gotten a STFU from his government. The irony is, I'm not sure about the theory, but I think he is basically right about the implementation. Trying to tune the device to the input frequency is just too hard with a noisy RF source and a cavity with dimensions that change as it heats. What we really need is to throw some computing power at it and tune the frequency to maintain Q.
because "as the frustrum twitches a little bit" doesn't have the same cache. :DToo early for a failed test, I believe. It might also be that Shawyer has put the squeeze on him and taken him private.
It's a great shame if he's walked, because (with no disrespect intended to other heroic DIYers) he had the best damn experimental design I've yet seen. I hope he reconsiders. I also hope he can beat that disease.
Could have been Shawyer and gotten a STFU from his government. The irony is, I'm not sure about the theory, but I think he is basically right about the implementation. Trying to tune the device to the input frequency is just too hard with a noisy RF source and a cavity with dimensions that change as it heats. What we really need is to throw some computing power at it and tune the frequency to maintain Q.
There for a while, I was wondering if Finkle was Einhorn, mostly because of TT's unwavering certainty that EmDrive was a sure thing (without anything to prove it yet) and his close connections with Shawyer. I asked and he said no.
This will be an interesting week for "As the Frustum Turns".
It is way, way too early to start jumping to conclusions. Anyone who does is not being fair. Until open and replicated experimental data is available, it's all noise as far as I'm concerned. As matters stand, there is nothing that is open and replicated.
The ironclad test is a space test. This cannot readily be fooled with artifacts. What's required for that is twin units in reasonably close proximity, one powered and one not, and in all other respects identical.
I know I'm a broken record, but IMHO there are many more uncontrollable factors in low earth orbit than in the lab, considering the minscule power available for the thruster on a cubesat.
In a 6u cubesat, we can get up to about 400W from the solar arrays and store enough to do a few KW of output for short periods (several minutes). That avionics bus design is on my computer now (I do avionics for a living).
If I was forced to do a cubesats flight test, I think I would do the 5u linear configuration, put the biggest battery I could in it, put the thruster on the end cube and see it I could get it rotating like a baton (as long as there is a way to detect the rotation - are there micro-RLGs?). This would be analogous to the rotating table tests some of the DiYers are contemplating. It would also avoid the issues of trying to isolate small velocity changes from drag and orbital mechanics effects.
There would still be challenges of stabilizing the spacecraft about the minor axis and what such a potential rotation would mean for power generation and communications.
How do you get angular momentum out of a system which starts out with none? Surely the entire stick will just translate? (replacing EmDrive with a rocket so it's something we are sure works well). Unless the centre of rotation has an oar bolted to it that dips into the Aetheric Aether (that was sarcasm) it won't spin.
How do you get angular momentum out of a system which starts out with none? Surely the entire stick will just translate? (replacing EmDrive with a rocket so it's something we are sure works well). Unless the centre of rotation has an oar bolted to it that dips into the Aetheric Aether (that was sarcasm) it won't spin.
How do you get angular momentum out of a system which starts out with none? Surely the entire stick will just translate? (replacing EmDrive with a rocket so it's something we are sure works well). Unless the centre of rotation has an oar bolted to it that dips into the Aetheric Aether (that was sarcasm) it won't spin.
If I was forced to do a cubesats flight test, I think I would do the 5u linear configuration, put the biggest battery I could in it, put the thruster on the end cube and see it I could get it rotating like a baton (as long as there is a way to detect the rotation - are there micro-RLGs?). This would be analogous to the rotating table tests some of the DiYers are contemplating. It would also avoid the issues of trying to isolate small velocity changes from drag and orbital mechanics effects.
There would still be challenges of stabilizing the spacecraft about the minor axis and what such a potential rotation would mean for power generation and communications.
3-Axis Gyro/Accelerometer('s) are very available in a single chip package ... and cheap :)
https://www.sparkfun.com/products/10937
@SeeShellWhere are you placing the dipoles, directly into the center of the modes?
How's this?
Oops. Yes, rockets can "pinwheel" even when the "pin" isn't stuck into anything.Couldn't you stabilize the little sat with gyroscopes and push against the stabilized sat with the mini drive??
So maybe orientation isn't a big deal for a space-based test after all. All that's needed is a record of the 3D accelerations.
@SeeShellWhere are you placing the dipoles, directly into the center of the modes?
How's this?
Look, go easy on the guy. He doesn't have the first clue about the physics of it. He just wants to be involved. You know, emotionally. 8)If 1N/kW could be proven, every aerospace company on the planet would be building these. Yes, it's that big a game-changer. Mind you, if I understand the physics correctly, a 100% efficient unit would be 1KN/KW right? That means currently we're only talking about a 0.1% efficiency (1N) and that would be enough to change the face of spaceflight. Figure this thing out and the money will come at you like a firehose (my conjecture).
I fail to see what is the relation between 1kN and 1kW that would make 1kN/kW "100% efficient". In SI units N is kg*m/s² and W is kg*m²/s3, the ratio of N/W is the inverse of a velocity in m/s. Saying that 1kN/kW is anything special is saying that 1m/s is a special speed, while the meter and the second (and hence the speed 1 m/s) are not natural units in any respect.
On the other hand 3.33*10-9N/W is a special value since it is the inverse of the very special natural speed c, and it is the natural limit of propulsion efficiency for anything that is "self fed" and self powered in deep space (i.e. not relying on incoming mass or energy flow or nearby objects field) if one includes the energy equivalent of spent mass in the case of classical action-reaction (chemical rocket, ion thruster...).
100% efficiency is 3.33*10-9N/W, above that is above 100% and leads to apparent overunity (energy wise). And this is not sounding like a broken record, more like time invariance of reality.
Before preparing the test in space of an EMDrive device it could be usefull to test it during the Zero-Gravity Parabolic Flights of a specialized plane. Such parabolic flight last up to 30 seconds which seems enough to detect a posssible move of the test specimen due to EMThrust.
Honestly, that's pretty insulting.
I probably have 2 or 3 clues, but certainly not the full deck, but I also know that which is why I stated it the way I did. Give that, what would be expected to be 100% efficiency? Certainly not 3.33*10-6N/KW? We've already seen results reported that are about 6 orders of magnitude higher.
Honestly, that's pretty insulting.
I probably have 2 or 3 clues, but certainly not the full deck, but I also know that which is why I stated it the way I did. Give that, what would be expected to be 100% efficiency? Certainly not 3.33*10-6N/KW? We've already seen results reported that are about 6 orders of magnitude higher.
Well, naturally, that depends on what exactly you mean by "efficiency". If you mean energy, then 3.336*10-9N/W is indeed the right one, as anything above that means that there is an speed less than c at which it starts gaining more kinetic energy than the EM energy being put in. Yes, the reported results are orders of magnitude higher, which is why so much has been written about conservation of energy (or lack thereof) of the EMdrives.
No way is a parabolic airplane flight loop long enough to do this test and see anything with a thrust less than about 1N.
Credentials to say this: I've done 160 parabolas testing a free-flying device...(last summer).
Edit: I'll modify that - you'd need about 0.1m/s2 acceleration to detect the change in the short zero-g time, so it would depend on the mass of the test device, but I'd think it would be difficult to get under several kg.
@SeeShellWhere are you placing the dipoles, directly into the center of the modes?
How's this?
I got a better(?) idea now: You can use as RF sealing a choke.Good plan. For all the modes which produce currents thru the gap, a good galvanic contact is necessary. While moving the plate the S-Parameter signal will look a little noisy that depends on the contact between the frustum and the plate(will be stable again after movement). The resonant frequency could be a little bit lower than calculated for a given length (MHz range, caused by longer current paths) if the metal seal is at the outer side.Thoughts to the gap...
So If I understand you right, the join of the conic section and the tuning tube is 0.2244 meters up from the large end plate which is at the big end of the conic section. The small end plate is then 0.0376m up from that join. Or do I have it backwards? This is what I understand now.
But what is the size of diameter of the tuning tube and the tuning plate (small base plate)? They can't be the same size so their must be a gap.
Small plate 160 mm, .032", O2 Free copper walls, Silver ~.30 um on endplates.
This should work just fine.
Thanks.
Shell
Check back later, have friends over.
But I thought you were going to use silver plated ceramic for the end plates? I liked that idea much better than copper end plates because of my hypothesis that thrust may be generated by tunnelling evanescent waves. A thin silver plate on ceramic would have a lot lower barrier height than copper end plates, although 30 um might be more than I'd like to see.
One thing that bugs me about my idea is that the math seems to be readily available to check for momentum from tunnelling evanescent waves, but I don't have the knowledge to apply it.
But back to the C-E drive, the small end plate cannot be the same diameter as the inner diameter of the tuning tube. You may try for the same size but it won't move if it is wedged in tightly and you want it to move. What is your expected tolerance on the two diameters? Millimetres? Hundreds of micrometers? Tens of micrometers? Evanescent waves will escape through this gap and we want to see them.
I'm looking at about a .0125mm gap. I've ordered 2 plates. The second one I'll modify for evanescent wave actions with a set pattern in the silver for just them and set a conductive seal between the plate and sidewalls. I just would like to see what meep does in the modes with the antennas you selected and not too worried about them this run.
Is that ok ?
Shell
Shell, is your favorite target mode still TE012? If yes the field strength(E) for this mode tend to zero near the "edge" of frustum and endplate. It is zero in the corner. There will be also no current flow between the frustum and the plate.
So if the gap is small its not "visible" from the viewpoint of this mode.
For some other mode shapes the gap can work as a slot antenna, it can radiate, not in the sense of evanescent waves.. The most interesting point is the length of the slot and thats the circumference in your case(not only the width of the gap is important).
It's easier to model in meep if it's treated as connected or a small gap which aero likes, in real life I'm going around the circumference of the plate with a beryllium copper gasket that will electrically connect to the frustum and seal the endcap but allow it to slide freely.
Shell
For TE01p that is not the case, no noise while moving the plate.
Again its a good plan. No better idea at the moment :)
More on photon "mass" within waveguides:
http://iopscience.iop.org/1063-7869/40/3/A05
These ain't your usual garden variety photons when they get confined it seems.
I got a better(?) idea now: You can use as RF sealing a choke.Again its a good plan. No better idea at the moment :)
http://www.radartutorial.eu/03.linetheory/tl13.en.html
http://www.microwaves101.com/encyclopedias/quarter-wave-tricks
I haven't even downed my first cup of coffee and I was wishing I could get a "Krell brain boost". (ref: Forbidden Planet) ;) Nice thought this morning! I like it.
I was reviewing this morning in how to "semi-control" the mode generation or at least limit in some fashion all the crosstalk between modes and was starting with this idea to do after I have some solid data. Instead of placing the antenna directly within the mode,in the frustum (makes it tough to adjust each externally). I can couple it like the attached picture and do it for the bottom mode and the top mode 90 degrees shifted (of course exciting a TE012)
I could tune each separately using a VNA at low power, turn on the top or the bottom or both for tests.
More coffee and draw what I'm thinking.
Shell
Very nice, you are dang good.. and fast! I was told that the loop should be just a little less than the chosen wavelength if we choose a loop. meep has a hard time modeling a loop and getting it to work right. aero needs to make sure he gets his phases correct for the two dipoles and not in phase.@SeeShellWhere are you placing the dipoles, directly into the center of the modes?
How's this?
@aero and SeeShells, what about these dimensions:
Db = 0.295 m
Ds = 0.160 m
L = 0.174 m
flat ends
TE012
2.47 GHz
free-space wavelength λ0 = 0.12134 m
big base wavelength λb =0.24186 m (cutoff)0.140 m
The dipole antenna should be placed at a distance from big end equal to 1/4 wavelength, but which λ:
λ0/4 = 30 mm
λb/4 = 35 mm
EDIT: If we choose to use a loop antenna instead of a dipole antenna, its diameter should be equal to the wavelength, but which wavelength: λ0 or λb? And should its length (diameter) be a bit below or above the chosen wavelength?
EDIT2: In the following proposal with θ = 23° and cylindrical extension = 120 mm, you could tune the small end to achieve TE012 resonance at L ≈ 174 mm, but also TE013 at L ≈ 262 mm, with interesting things to measure between the two Q factors and the plate most closely to the vertex of the cone.
BTW as already explained by TheTraveller, Shawyer may have gone from TE012 to TE013 to accommodate a bigger length and bigger volume and enhance the Q. TE012 frustums have a shallow height.
Dr. Rodal,
What were the dimensions of your spherical end model (of SeeShell's cavity) that resonates at 2.47 GHz? In particular, what were the r1 and r2 values? I've attached the image you posted, this is the one I'm asking about.
aero
I like this thought somewhat. More than once I've seen the relationship between this cavity and a particle accelerator. (Warning Warning Will Robinson, Engineer thinking physics alert)More on photon "mass" within waveguides:
http://iopscience.iop.org/1063-7869/40/3/A05
These ain't your usual garden variety photons when they get confined it seems.
AFAIK, confined particles are represented by standing waves. Vice versa, any standing wave is then equivalent to a confined particle including properties such as mass etc. Depending on chosen mode(s), the standing wave distribution within the waveguide could then represent not just one single confined particle, but actually a sort of atomic lattice of dynamically created massive particle equivalents. Following this line of thought, there is maybe an optimal standing wave distribution within any waveguide that maximizes this effect, i.e. creating a maximally massive particle equivalent.
If I understood Dr. Rodal correctly, then there is only an observable stress/force imbalance if the RF feed is on? I'm getting the impression that what's actually happening in this device is this:
- Incoming RF energy creates standing wave distributions, which are equivalent to confined massive particles within the waveguide
- Depending on the standing wave distributions, they represent an actual massive particle structure with varying topology
- If this massive particle structure can be regarded as an actual massive confined particle structure, then the Heisenberg uncertainty principle should apply, too (as does for any other real particle, no matter if (pseudo) static or dynamic)
- Since the location as well as the impulse of this particle structure are smeared according to Heisenberg, this dynamical particle structure statistically squeezes more against the smaller waveguide end volume than it squeezes against the larger waveguide end volume or (!) vice versa - depending on the topology of the dynamically created mode dependent massive particle structure
- This squeeze stress shows up as a real net force against the small end or (!) the large end, depending on mode dependent particle structure topology
- The imbalanced Heisenberg squeeze-stress-imparted impulse on the waveguide finds its balance by energy conversion into heat (= chaotic local impulse) within the waveguide's crystal lattice
- The active RF feed is like a lifeline to the dynamic process of creating and upholding an energy delta that gives the confined particle structure its 'life'.
- I'm sure that MEEP is not made to take Heisenberg's uncertainty principle into consideration when simulating Maxwell's equations. Wherever the dynamic particle structure is squeezed within a real cavity .. EM stress and forces are bound to come into existence. This might be key to understand what's happening here.
At least that's how my naive engineering mind imagines what's going on. Comments are welcome :) .
Dr. Rodal,
What were the dimensions of your spherical end model (of SeeShell's cavity) that resonates at 2.47 GHz? In particular, what were the r1 and r2 values? I've attached the image you posted, this is the one I'm asking about.
aero
bigDiameter = 0.295(*meter*);
smallDiameter = 0.160(*meter*);
axialLength = 0.163(*meter*);
r1= 0.20114 m (*small spherical radius*)
r2= 0.370852 m (*big spherical radius*)
theta = 22.495 degrees (*half cone angle*)
TE011 = 1.84088 GHz
TE012 = 2.45008 GHz Q = 73,800
TE013 = 3.15166 GHz Q= 70,000
using n=1
assuming flat ends
Actually, you would be well advised to make the length somewhat smaller than 0.163 meters, so that you can tune it with the longer length of the cylindrical extension.
Remember that using the cylindrical extension to increase the length of the cavity, will lower the natural frequencies of given mode shapes
Recommendations to place the RF feed based on free-space wavelength, IMHO, do NOT make sense. Inside the cavity, there is no such free-space wavelength, instead there are wave-patterns with lengths governed by spherical Bessel functions and associated Legendre functions.
Kludgy spreadsheets based on drastic approximations that are unable to predict or even show the mode shapes, unable to calculate the Q, unable to calculate the electromagnetic fields, and much less the wave-pattern wavelenghts inside the cavity are not an excuse to use the free-space wavelength.
To locate the antenna inside a Meep model based on such kludgy spreadsheets and approximation does not make sense to me: look at the wavelengths of the wavepatterns inside Meep: they correspond to the spherical Bessel functions. They do NOT correspond to the free space wavelength.
There is also misinterpretations concerning Shawyer and TE013.
Shawyer used TE013 for the Flight Thruster because it operates at a much higher frequency (3.85 GHz instead of 2.45 GHz), not because of something having to do with volume.
On the contrary, Shawyer, instead of using longer lengths, has been doing all the contrary: it has moved to higher cone angles in a progressive way: using 30 degrees for the superconducting design.
Also for the superconducting design Shawyer has been moving to lower modes.
SPR Ltd, R. Shawyer, Demonstration 2.45 GHz TE012 19.28 degrees
SPR Ltd, R. Shawyer, Demonstration 3.85 GHz TE013 20.87 degrees
Yang has used TE012 in her tests, according to her paper.
Look at the attached picture of Shawyer's superconducting design:
NO TE013 mode here
NO move of Shawyer towards longer lengths. On the contrary, Shawyer has been moving to shorter lengths and higher cone angles.
Ditto for McCullloch who has been writing about the problems associated with long lengths.
Since Shell is going to be testing a design with long length and small cone angle (the Yang/Shell cone) it makes more sense that her alternate design should be a shorter length, high cone angle design.
We show that the Stokes parameters for
an evanescent wave unambiguously reveals that every fast
decaying evanescent wave is inherently circularly polarized
irrespective of how it originates. Furthermore, this
inherent handedness (spin) is locked to the direction of
propagation (momentum). This information hidden in
the Stokes parameters has been overlooked till date and
is in stark contrast to the existing knowledge on propagating
waves.
I like this thought somewhat. More than once I've seen the relationship between this cavity and a particle accelerator. (Warning Warning Will Robinson, Engineer thinking physics alert)More on photon "mass" within waveguides:
http://iopscience.iop.org/1063-7869/40/3/A05
These ain't your usual garden variety photons when they get confined it seems.
AFAIK, confined particles are represented by standing waves. Vice versa, any standing wave is then equivalent to a confined particle including properties such as mass etc. Depending on chosen mode(s), the standing wave distribution within the waveguide could then represent not just one single confined particle, but actually a sort of atomic lattice of dynamically created massive particle equivalents. Following this line of thought, there is maybe an optimal standing wave distribution within any waveguide that maximizes this effect, i.e. creating a maximally massive particle equivalent.
If I understood Dr. Rodal correctly, then there is only an observable stress/force imbalance if the RF feed is on? I'm getting the impression that what's actually happening in this device is this:
- Incoming RF energy creates standing wave distributions, which are equivalent to confined massive particles within the waveguide
- Depending on the standing wave distributions, they represent an actual massive particle structure with varying topology
- If this massive particle structure can be regarded as an actual massive confined particle structure, then the Heisenberg uncertainty principle should apply, too (as does for any other real particle, no matter if (pseudo) static or dynamic)
- Since the location as well as the impulse of this particle structure are smeared according to Heisenberg, this dynamical particle structure statistically squeezes more against the smaller waveguide end volume than it squeezes against the larger waveguide end volume or (!) vice versa - depending on the topology of the dynamically created mode dependent massive particle structure
- This squeeze stress shows up as a real net force against the small end or (!) the large end, depending on mode dependent particle structure topology
- The imbalanced Heisenberg squeeze-stress-imparted impulse on the waveguide finds its balance by energy conversion into heat (= chaotic local impulse) within the waveguide's crystal lattice
- The active RF feed is like a lifeline to the dynamic process of creating and upholding an energy delta that gives the confined particle structure its 'life'.
- I'm sure that MEEP is not made to take Heisenberg's uncertainty principle into consideration when simulating Maxwell's equations. Wherever the dynamic particle structure is squeezed within a real cavity .. EM stress and forces are bound to come into existence. This might be key to understand what's happening here.
At least that's how my naive engineering mind imagines what's going on. Comments are welcome :) .
Let's see, if the mode . . .
"creates standing wave distributions, which are equivalent to confined massive particles within the waveguide
- Depending on the standing wave distributions, they represent an actual massive particle structure with varying topology
- If this massive particle structure can be regarded as an actual massive confined particle structure, then the Heisenberg uncertainty principle should apply, too (as does for any other real particle, no matter if (pseudo) static or dynamic)"
And then during a mode switch (which happens withing the cavity) it promptly decays into an evanescent wave into the small end of the cavity, the question would be... do the evanescent waves carry that increased spin and momentum imparting it into the small end? Let's not forget that an evanescent wave is a weird duck that is now only beginning to be understood.
I think it's entirely possible to pump up a photon and accelerate it towards the end of the cavity right at the mode decay. Will it violate CoM if the now massive photon imparts motion and apparent thrust in the small end direction? No. What if I take those pumped up photons before I hit the endplate and decay them into evanescent waves which can't backscatter back into the large end which is the action that Conservation of Momentum uses. Added: When a photon is emitted or absorbed, it transfers h bar of angular momentum and the associated energy is also transferred.
This is one reason I wanted the tuning chamber in the small end. And I like X_ray's idea of the trap and I can insert a probe into it to monitor energy conditions.
Reading two papers right now and here is one of my favorite things cropping up with the Golden Ratio....
"The universality of this phenomenon is revealed by analyzing, in detail, the cases corresponding to a) total internal reflection (TIR) b) waveguides c)optical fibers d) surface electromagnetic waves. We also show the existence of a unique criterion in TIR (”golden
ratio condition”) " http://arxiv.org/abs/1504.06361
And the other which is kind of interesting...
http://onlyspacetime.com/QM-Foundation.pdf
I'm going to finish these up and clean up the mess I have in the shop (it wasn't me!).
I still need a Krell brain boost! To heck with those pesky monsters from the Id.
Shell
just added a thought...
More on photon "mass" within waveguides:
http://iopscience.iop.org/1063-7869/40/3/A05
These ain't your usual garden variety photons when they get confined it seems.
I took several meep images (many say they are poo for detective work, I vehemently disagree) and scaled them to dimension, measured the center mode positions and compared that with the calculations used in other methods and there is a discrepancy between the two and your quite correct it is the spherical Bessel functions. You can see that in my layout of a overlay image. Threw me for a loop. ;)
More on photon "mass" within waveguides:
http://iopscience.iop.org/1063-7869/40/3/A05
These ain't your usual garden variety photons when they get confined it seems.
AFAIK, confined particles are represented by standing waves. Vice versa, any standing wave is then equivalent to a confined particle including properties such as mass etc. Depending on chosen mode(s), the standing wave distribution within the waveguide could then represent not just one single confined particle, but actually a sort of atomic lattice of dynamically created massive particle equivalents. Following this line of thought, there is maybe an optimal standing wave distribution within any waveguide that maximizes this effect, i.e. creating a maximally massive particle equivalent.
If I understood Dr. Rodal correctly, then there is only an observable stress/force imbalance if the RF feed is on? I'm getting the impression that what's actually happening in this device is this:
- Incoming RF energy creates standing wave distributions, which are equivalent to confined massive particles within the waveguide
- Depending on the standing wave distributions, they represent an actual massive particle structure with varying topology
- If this massive particle structure can be regarded as an actual massive confined particle structure, then the Heisenberg uncertainty principle should apply, too (as does for any other real particle, no matter if (pseudo) static or dynamic)
- Since the location as well as the impulse of this particle structure are smeared according to Heisenberg, this dynamical particle structure statistically squeezes more against the smaller waveguide end volume than it squeezes against the larger waveguide end volume or (!) vice versa - depending on the topology of the dynamically created mode dependent massive particle structure
- This squeeze stress shows up as a real net force against the small end or (!) the large end, depending on mode dependent particle structure topology
- The imbalanced Heisenberg squeeze-stress-imparted impulse on the waveguide finds its balance by energy conversion into heat (= chaotic local impulse) within the waveguide's crystal lattice
- The active RF feed is like a lifeline to the dynamic process of creating and upholding an energy delta that gives the confined particle structure its 'life'.
- I'm sure that MEEP is not made to take Heisenberg's uncertainty principle into consideration when simulating Maxwell's equations. Wherever the dynamic particle structure is squeezed within a real cavity .. EM stress and forces are bound to come into existence. This might be key to understand what's happening here.
At least that's how my naive engineering mind imagines what's going on. Comments are welcome :) .
Great question....I like this thought somewhat. More than once I've seen the relationship between this cavity and a particle accelerator. (Warning Warning Will Robinson, Engineer thinking physics alert)More on photon "mass" within waveguides:
http://iopscience.iop.org/1063-7869/40/3/A05
These ain't your usual garden variety photons when they get confined it seems.
AFAIK, confined particles are represented by standing waves. Vice versa, any standing wave is then equivalent to a confined particle including properties such as mass etc. Depending on chosen mode(s), the standing wave distribution within the waveguide could then represent not just one single confined particle, but actually a sort of atomic lattice of dynamically created massive particle equivalents. Following this line of thought, there is maybe an optimal standing wave distribution within any waveguide that maximizes this effect, i.e. creating a maximally massive particle equivalent.
If I understood Dr. Rodal correctly, then there is only an observable stress/force imbalance if the RF feed is on? I'm getting the impression that what's actually happening in this device is this:
- Incoming RF energy creates standing wave distributions, which are equivalent to confined massive particles within the waveguide
- Depending on the standing wave distributions, they represent an actual massive particle structure with varying topology
- If this massive particle structure can be regarded as an actual massive confined particle structure, then the Heisenberg uncertainty principle should apply, too (as does for any other real particle, no matter if (pseudo) static or dynamic)
- Since the location as well as the impulse of this particle structure are smeared according to Heisenberg, this dynamical particle structure statistically squeezes more against the smaller waveguide end volume than it squeezes against the larger waveguide end volume or (!) vice versa - depending on the topology of the dynamically created mode dependent massive particle structure
- This squeeze stress shows up as a real net force against the small end or (!) the large end, depending on mode dependent particle structure topology
- The imbalanced Heisenberg squeeze-stress-imparted impulse on the waveguide finds its balance by energy conversion into heat (= chaotic local impulse) within the waveguide's crystal lattice
- The active RF feed is like a lifeline to the dynamic process of creating and upholding an energy delta that gives the confined particle structure its 'life'.
- I'm sure that MEEP is not made to take Heisenberg's uncertainty principle into consideration when simulating Maxwell's equations. Wherever the dynamic particle structure is squeezed within a real cavity .. EM stress and forces are bound to come into existence. This might be key to understand what's happening here.
At least that's how my naive engineering mind imagines what's going on. Comments are welcome :) .
Let's see, if the mode . . .
"creates standing wave distributions, which are equivalent to confined massive particles within the waveguide
- Depending on the standing wave distributions, they represent an actual massive particle structure with varying topology
- If this massive particle structure can be regarded as an actual massive confined particle structure, then the Heisenberg uncertainty principle should apply, too (as does for any other real particle, no matter if (pseudo) static or dynamic)"
And then during a mode switch (which happens withing the cavity) it promptly decays into an evanescent wave into the small end of the cavity, the question would be... do the evanescent waves carry that increased spin and momentum imparting it into the small end? Let's not forget that an evanescent wave is a weird duck that is now only beginning to be understood.
I think it's entirely possible to pump up a photon and accelerate it towards the end of the cavity right at the mode decay. Will it violate CoM if the now massive photon imparts motion and apparent thrust in the small end direction? No. What if I take those pumped up photons before I hit the endplate and decay them into evanescent waves which can't backscatter back into the large end which is the action that Conservation of Momentum uses. Added: When a photon is emitted or absorbed, it transfers h bar of angular momentum and the associated energy is also transferred.
This is one reason I wanted the tuning chamber in the small end. And I like X_ray's idea of the trap and I can insert a probe into it to monitor energy conditions.
Reading two papers right now and here is one of my favorite things cropping up with the Golden Ratio....
"The universality of this phenomenon is revealed by analyzing, in detail, the cases corresponding to a) total internal reflection (TIR) b) waveguides c)optical fibers d) surface electromagnetic waves. We also show the existence of a unique criterion in TIR (”golden
ratio condition”) " http://arxiv.org/abs/1504.06361
And the other which is kind of interesting...
http://onlyspacetime.com/QM-Foundation.pdf
I'm going to finish these up and clean up the mess I have in the shop (it wasn't me!).
I still need a Krell brain boost! To heck with those pesky monsters from the Id.
Shell
just added a thought...
Would the opposite reaction going to heat create a measurable amount of heating? Could it show up as an unusual amount if warping of the frustum?
Thanks Shell for this paper: http://arxiv.org/abs/1504.06361Weird huh? I always though this.QuoteWe show that the Stokes parameters for
an evanescent wave unambiguously reveals that every fast
decaying evanescent wave is inherently circularly polarized
irrespective of how it originates. Furthermore, this
inherent handedness (spin) is locked to the direction of
propagation (momentum). This information hidden in
the Stokes parameters has been overlooked till date and
is in stark contrast to the existing knowledge on propagating
waves.
If given the Stokes parameters
(https://upload.wikimedia.org/math/1/c/f/1cf3fd6cb08ae3b1dd900ee419a0bfe5.png)
(I is the total intensity of the beam, and p is the degree of polarization, constrained by 0 ≤ p ≤ 1. The phase information of the polarized light is not recorded in the stokes parameters. The phase information is lost in this description)
(https://upload.wikimedia.org/math/8/a/0/8a07207c8a1fe1f20fc7169119c2e5a2.png)
(https://upload.wikimedia.org/math/6/d/0/6d06e4a0a7234143afd2748766d30193.png)
one can solve for the spherical coordinates with the following equations
(https://upload.wikimedia.org/math/0/6/8/0684ab975b0154b0cd5d1028b4405c6d.png)
(https://upload.wikimedia.org/wikipedia/commons/thumb/b/bf/Poincar%C3%A9_sphere.svg/220px-Poincar%C3%A9_sphere.svg.png)
I took several meep images (many say they are poo for detective work, I vehemently disagree) and scaled them to dimension, measured the center mode positions and compared that with the calculations used in other methods and there is a discrepancy between the two and your quite correct it is the spherical Bessel functions. You can see that in my layout of a overlay image. Threw me for a loop. ;)
As Rodal just explained, pay attention to NOT use the free-space wavelength for anything inside the frustum!
Yes at 2.45 GHz in free space the microwaves have a wavelength λ0 ≈ 12 cm.
But inside the cavity, the wavelength is larger. In your frustum, the wavelength at big end is λb ≈ 14 cm, and it is way greater at small end where λs ≈ 34 cm.
But this is from a kludgy spreadsheet ;) I am aware that this spreadsheet should only be used to make inroads into a problem and that some more advanced technique and simulation software should precisely compute data before building the real thing. I like to think of the spreadsheet as SketchUp for 3D modeling. It allows to get any idea very fast.
Very nice, you are dang good.. and fast! I was told that the loop should be just a little less than the chosen wavelength if we choose a loop. meep has a hard time modeling a loop and getting it to work right. aero needs to make sure he gets his phases correct for the two dipoles and not in phase.
I know you have squeezed that light. And there must be a carrier of that momentum xfer, right? "evanescent electromagnetic waves can carry four distinct momenta and three distinct spin angular momenta"More on photon "mass" within waveguides:
http://iopscience.iop.org/1063-7869/40/3/A05
These ain't your usual garden variety photons when they get confined it seems.
AFAIK, confined particles are represented by standing waves. Vice versa, any standing wave is then equivalent to a confined particle including properties such as mass etc. Depending on chosen mode(s), the standing wave distribution within the waveguide could then represent not just one single confined particle, but actually a sort of atomic lattice of dynamically created massive particle equivalents. Following this line of thought, there is maybe an optimal standing wave distribution within any waveguide that maximizes this effect, i.e. creating a maximally massive particle equivalent.
If I understood Dr. Rodal correctly, then there is only an observable stress/force imbalance if the RF feed is on? I'm getting the impression that what's actually happening in this device is this:
- Incoming RF energy creates standing wave distributions, which are equivalent to confined massive particles within the waveguide
- Depending on the standing wave distributions, they represent an actual massive particle structure with varying topology
- If this massive particle structure can be regarded as an actual massive confined particle structure, then the Heisenberg uncertainty principle should apply, too (as does for any other real particle, no matter if (pseudo) static or dynamic)
- Since the location as well as the impulse of this particle structure are smeared according to Heisenberg, this dynamical particle structure statistically squeezes more against the smaller waveguide end volume than it squeezes against the larger waveguide end volume or (!) vice versa - depending on the topology of the dynamically created mode dependent massive particle structure
- This squeeze stress shows up as a real net force against the small end or (!) the large end, depending on mode dependent particle structure topology
- The imbalanced Heisenberg squeeze-stress-imparted impulse on the waveguide finds its balance by energy conversion into heat (= chaotic local impulse) within the waveguide's crystal lattice
- The active RF feed is like a lifeline to the dynamic process of creating and upholding an energy delta that gives the confined particle structure its 'life'.
- I'm sure that MEEP is not made to take Heisenberg's uncertainty principle into consideration when simulating Maxwell's equations. Wherever the dynamic particle structure is squeezed within a real cavity .. EM stress and forces are bound to come into existence. This might be key to understand what's happening here.
At least that's how my naive engineering mind imagines what's going on. Comments are welcome :) .
I've referred to "squeezed light" a few times here. When the position is squeezed by the small end, the momentum increases, per Heisenberg's equation delta_x*delta_p = h/2. That causes momentum transfer at the small end to be larger than at the big end. How to prove it?
Todd
Very nice, you are dang good.. and fast! I was told that the loop should be just a little less than the chosen wavelength if we choose a loop. meep has a hard time modeling a loop and getting it to work right. aero needs to make sure he gets his phases correct for the two dipoles and not in phase.
OK, but if the perimeter of a loop antenna should be just below the wavelength, its diameter d = λ/π would be really tiny near the big base: I roughly calculated the loop diameter between 38 and 44 mm according to the position and frequency. So maybe two dipole antennas located further from each others, within the mode nodes, would be preferable?
I took several meep images (many say they are poo for detective work, I vehemently disagree) and scaled them to dimension, measured the center mode positions and compared that with the calculations used in other methods and there is a discrepancy between the two and your quite correct it is the spherical Bessel functions. You can see that in my layout of a overlay image. Threw me for a loop. ;)
As Rodal just explained, pay attention to NOT use the free-space wavelength for anything inside the frustum!
Yes at 2.45 GHz in free space the microwaves have a wavelength λ0 ≈ 12 cm.
But inside the cavity, the wavelength is larger. In your frustum, the wavelength at big end is λb ≈ 14 cm, and it is way greater at small end where λs ≈ 34 cm.
But this is from a kludgy spreadsheet ;) I am aware that this spreadsheet should only be used to make inroads into a problem and that some more advanced technique and simulation software should precisely compute data before building the real thing. I like to think of the spreadsheet as SketchUp for 3D modeling. It allows to get any idea very fast.
Dr. Rodal,
What were the dimensions of your spherical end model (of SeeShell's cavity) that resonates at 2.47 GHz? In particular, what were the r1 and r2 values? I've attached the image you posted, this is the one I'm asking about.
aero
bigDiameter = 0.295(*meter*);
smallDiameter = 0.160(*meter*);
axialLength = 0.163(*meter*);
r1= 0.20114 m (*small spherical radius*)
r2= 0.370852 m (*big spherical radius*)
theta = 22.495 degrees (*half cone angle*)
TE011 = 1.84088 GHz
TE012 = 2.45008 GHz Q = 73,800
TE013 = 3.15166 GHz Q= 70,000
using n=1
assuming flat ends
Actually, you would be well advised to make the length somewhat smaller than 0.163 meters, so that you can tune it with the longer length of the cylindrical extension.
Remember that using the cylindrical extension to increase the length of the cavity, will lower the natural frequencies of given mode shapes
Recommendations to place the RF feed based on free-space wavelength, IMHO, do NOT make sense. Inside the cavity, there is no such free-space wavelength, instead there are wave-patterns with lengths governed by spherical Bessel functions and associated Legendre functions.
Kludgy spreadsheets based on drastic approximations that are unable to predict or even show the mode shapes, unable to calculate the Q, unable to calculate the electromagnetic fields, and much less the wave-pattern wavelenghts inside the cavity are not an excuse to use the free-space wavelength.
To locate the antenna inside a Meep model based on such kludgy spreadsheets and approximation does not make sense to me: look at the wavelengths of the wavepatterns inside Meep: they correspond to the spherical Bessel functions. They do NOT correspond to the free space wavelength.
There is also misinterpretations concerning Shawyer and TE013.
Shawyer used TE013 for the Flight Thruster because it operates at a much higher frequency (3.85 GHz instead of 2.45 GHz), not because of something having to do with volume.
On the contrary, Shawyer, instead of using longer lengths, has been doing all the contrary: it has moved to higher cone angles in a progressive way: using 30 degrees for the superconducting design.
Also for the superconducting design Shawyer has been moving to lower modes.
SPR Ltd, R. Shawyer, Demonstration 2.45 GHz TE012 19.28 degrees
SPR Ltd, R. Shawyer, Demonstration 3.85 GHz TE013 20.87 degrees
Yang has used TE012 in her tests, according to her paper.
Look at the attached picture of Shawyer's superconducting design:
NO TE013 mode here
NO move of Shawyer towards longer lengths. On the contrary, Shawyer has been moving to shorter lengths and higher cone angles.
Ditto for McCullloch who has been writing about the problems associated with long lengths.
Since Shell is going to be testing a design with long length and small cone angle (the Yang/Shell cone) it makes more sense that her alternate design should be a shorter length, high cone angle design.
The wave-pattern wavelengths for TE012 = 2.45008 GHz for these dimensions:
bigDiameter = 0.295(*meter*);
smallDiameter = 0.160(*meter*);
axialLength = 0.163(*meter*);
r1= 0.20114 m (*small spherical radius*)
r2= 0.370852 m (*big spherical radius*)
theta = 22.495 degrees (*half cone angle*)
TE011 = 1.84088 GHz
TE012 = 2.45008 GHz Q = 73,800
TE013 = 3.15166 GHz Q= 70,000
bigDiameter = 0.295(*meter*);
smallDiameter = 0.160(*meter*);
axialLength = 0.163(*meter*);
has a first absolute value maximum, for the wave-pattern next to the small base that occurs at:
28.1465% of the distance between the bases, measuring from the small base
which for axial length=0.163 m
0.0458789 m axial distance from the small base
this is where I think the antenna should be located when locating the antenna near the small base
____________________________________________________________________________________
the next absolute value maximum, for the wave-pattern next to the big base occurs at:
77.3927% of the distance between the bases, measuring from the small base
or equivalently
22.6073% of the distance between the bases, measuring from the big base
which for axial length=0.163 m means
0.12615 m axial distance from the small base , or equivalently
0.0368499 m axial distance from the big base
this is where I think the antenna should be located when locating the antenna near the big base
____________________________________________________________________________________
Thus, optimal locations are NOT at 1/4 of the axial distance, rather the optimal location near the small base is further away, at 28.1465% of the distance from the small base, while the optimal location near the big base is closer to the big base, at 22.6073% of the distance from the small base
These optimal distances for TE012 are approximately +/- 10% different from the 1/4 distance
No way is a parabolic airplane flight loop long enough to do this test and see anything with a thrust less than about 1N.
Credentials to say this: I've done 160 parabolas testing a free-flying device...(last summer).
Edit: I'll modify that - you'd need about 0.1m/s2 acceleration to detect the change in the short zero-g time, so it would depend on the mass of the test device, but I'd think it would be difficult to get under several kg.
If I consider a test device weighting 100 Kg (including cavity, DC Li-Ion battery, RF harness, source and power amplifier (TWT + EPC), hold-on and release mechanism..) with a thrust of 0.1 N, this would lead to an acceleration gamma of 0.001 m/s² and so to a total displacement of 0.2 m for a test duration t of 20 seconds (1/2 gamma t²). Dont'you think that this displacement could be properly observed if we use a small vaccum test chamber with observation capability surrounding at 30 cm distance the test device ?
Of course we should have calibration parabolic flights without thrust to evaluate the 0-thrust displacement.
There is also the possibility to use a vaccuum drop tower which offers weightless or microgravity environment for a duration of 5.18 seconds (NASA data : http://facilities.grc.nasa.gov/zerog/ (http://facilities.grc.nasa.gov/zerog/)). The accurate measure of the free fall trajectory versus time should provide the thrust characteristics versus time.
I hire you for the flight test operation as you seem well experimented in this matter ;) !! (nausea-free prooved :D ?)
NSF-1701 on fulcrum ready to flight test: https://youtu.be/XQ5HOYeJf4Y
Good idea...I'll print one up before tuesdayNSF-1701 on fulcrum ready to flight test: https://youtu.be/XQ5HOYeJf4Y
Just wondering if you are going to attach grid paper to the laser target to more easily observe/measure any deflection?
No way is a parabolic airplane flight loop long enough to do this test and see anything with a thrust less than about 1N.
Credentials to say this: I've done 160 parabolas testing a free-flying device...(last summer).
Edit: I'll modify that - you'd need about 0.1m/s2 acceleration to detect the change in the short zero-g time, so it would depend on the mass of the test device, but I'd think it would be difficult to get under several kg.
If I consider a test device weighting 100 Kg (including cavity, DC Li-Ion battery, RF harness, source and power amplifier (TWT + EPC), hold-on and release mechanism..) with a thrust of 0.1 N, this would lead to an acceleration gamma of 0.001 m/s² and so to a total displacement of 0.2 m for a test duration t of 20 seconds (1/2 gamma t²). Dont'you think that this displacement could be properly observed if we use a small vaccum test chamber with observation capability surrounding at 30 cm distance the test device ?
Of course we should have calibration parabolic flights without thrust to evaluate the 0-thrust displacement.
There is also the possibility to use a vaccuum drop tower which offers weightless or microgravity environment for a duration of 5.18 seconds (NASA data : http://facilities.grc.nasa.gov/zerog/ (http://facilities.grc.nasa.gov/zerog/)). The accurate measure of the free fall trajectory versus time should provide the thrust characteristics versus time.
I hire you for the flight test operation as you seem well experimented in this matter ;) !! (nausea-free prooved :D ?)
NSF-1701 on fulcrum ready to flight test: https://youtu.be/XQ5HOYeJf4Y
Good idea...I'll print one up before tuesdayNSF-1701 on fulcrum ready to flight test: https://youtu.be/XQ5HOYeJf4Y
Just wondering if you are going to attach grid paper to the laser target to more easily observe/measure any deflection?
NSF-1701 on fulcrum ready to flight test: https://youtu.be/XQ5HOYeJf4Y
Can you set up a second camera watching the frustum and rig while the first looks at the paper? Not perfect, but the first thing I'd think of with the camera only recording the laser moving is that you might be physically manipulating the rig. Given that the lights are going to be off, I realize that this would be difficult. Maybe some form of thermal camera? Then again I can understand just wanting the verify that the thing is giving some kind of detectable result before fiddling with it more.
A second thought is that with the current setup, the large end is at the top. The discussion on the site has stated that the small end is where the force will occur. Since the small end of the frustum is at the bottom I see a potential bias.Good idea...I'll print one up before tuesdayNSF-1701 on fulcrum ready to flight test: https://youtu.be/XQ5HOYeJf4Y
Just wondering if you are going to attach grid paper to the laser target to more easily observe/measure any deflection?
Thanks for all the good ideas. I will take as many as I can into consideration on Tuesday morning before the 2 pm flight test. Keep the ideas coming, this is a collaboration...always has been.You're very welcome. Videoing the laser behind the paper with black electrical tape defining the graph works well. I even tried a little vegetable oil on the paper to increase light transmission.
(video snip)
Can you set up a second camera watching the frustum and rig while the first looks at the paper? Not perfect, but the first thing I'd think of with the camera only recording the laser moving is that you might be physically manipulating the rig. Given that the lights are going to be off, I realize that this would be difficult. Maybe some form of thermal camera? Then again I can understand just wanting the verify that the thing is giving some kind of detectable result before fiddling with it more.
I have a suggestion that might Kill three birds with one stone rfmwguy.
Take your camera and shoot the backside of the graph paper. Easier for your camera to see the red dot without blossoming out from sensitivity to the red light.
You can see the device and the paper in one view if it's set up right.
On the front of the paper run two strips of electrical tape up and down separated by a small gap maybe 1/4 inch. It will help define the movement. Like a vertical bar graph display and make your lines heavy horizontally when you do the graph paper.
One other thing, twist the power leads together and the heater leads together, you'll reduce noise and cancel AC effects the leads may carry.
Have to confess, I did a test firing this AM. No arcs on terminal. Humidity was low. Will measure that on Tuesday. Yes, I'm avoiding anything next to hv insulation. Proper wire for this is silicone insulated...like on oscilloscope test lead, only heavier guage. Could not locate easily.(video snip)
Can you set up a second camera watching the frustum and rig while the first looks at the paper? Not perfect, but the first thing I'd think of with the camera only recording the laser moving is that you might be physically manipulating the rig. Given that the lights are going to be off, I realize that this would be difficult. Maybe some form of thermal camera? Then again I can understand just wanting the verify that the thing is giving some kind of detectable result before fiddling with it more.
I have a suggestion that might Kill three birds with one stone rfmwguy.
Take your camera and shoot the backside of the graph paper. Easier for your camera to see the red dot without blossoming out from sensitivity to the red light.
You can see the device and the paper in one view if it's set up right.
On the front of the paper run two strips of electrical tape up and down separated by a small gap maybe 1/4 inch. It will help define the movement. Like a vertical bar graph display and make your lines heavy horizontally when you do the graph paper.
One other thing, twist the power leads together and the heater leads together, you'll reduce noise and cancel AC effects the leads may carry.
I also suggested twisting the leads, but I'm not sure the insulation on the red wire is actually 4000V rated. If not, don't do it, it may breakdown through to the other wires. I'm not sure that terminal block is good for 4000V either. Humidity may cause it to arc to ground.
Todd
I like this thought somewhat. More than once I've seen the relationship between this cavity and a particle accelerator. (Warning Warning Will Robinson, Engineer thinking physics alert)More on photon "mass" within waveguides:
http://iopscience.iop.org/1063-7869/40/3/A05
These ain't your usual garden variety photons when they get confined it seems.
AFAIK, confined particles are represented by standing waves. Vice versa, any standing wave is then equivalent to a confined particle including properties such as mass etc. Depending on chosen mode(s), the standing wave distribution within the waveguide could then represent not just one single confined particle, but actually a sort of atomic lattice of dynamically created massive particle equivalents. Following this line of thought, there is maybe an optimal standing wave distribution within any waveguide that maximizes this effect, i.e. creating a maximally massive particle equivalent.
If I understood Dr. Rodal correctly, then there is only an observable stress/force imbalance if the RF feed is on? I'm getting the impression that what's actually happening in this device is this:
- Incoming RF energy creates standing wave distributions, which are equivalent to confined massive particles within the waveguide
- Depending on the standing wave distributions, they represent an actual massive particle structure with varying topology
- If this massive particle structure can be regarded as an actual massive confined particle structure, then the Heisenberg uncertainty principle should apply, too (as does for any other real particle, no matter if (pseudo) static or dynamic)
- Since the location as well as the impulse of this particle structure are smeared according to Heisenberg, this dynamical particle structure statistically squeezes more against the smaller waveguide end volume than it squeezes against the larger waveguide end volume or (!) vice versa - depending on the topology of the dynamically created mode dependent massive particle structure
- This squeeze stress shows up as a real net force against the small end or (!) the large end, depending on mode dependent particle structure topology
- The imbalanced Heisenberg squeeze-stress-imparted impulse on the waveguide finds its balance by energy conversion into heat (= chaotic local impulse) within the waveguide's crystal lattice
- The active RF feed is like a lifeline to the dynamic process of creating and upholding an energy delta that gives the confined particle structure its 'life'.
- I'm sure that MEEP is not made to take Heisenberg's uncertainty principle into consideration when simulating Maxwell's equations. Wherever the dynamic particle structure is squeezed within a real cavity .. EM stress and forces are bound to come into existence. This might be key to understand what's happening here.
At least that's how my naive engineering mind imagines what's going on. Comments are welcome :) .
Let's see, if the mode . . .
"creates standing wave distributions, which are equivalent to confined massive particles within the waveguide
- Depending on the standing wave distributions, they represent an actual massive particle structure with varying topology
- If this massive particle structure can be regarded as an actual massive confined particle structure, then the Heisenberg uncertainty principle should apply, too (as does for any other real particle, no matter if (pseudo) static or dynamic)"
And then during a mode switch (which happens withing the cavity) it promptly decays into an evanescent wave into the small end of the cavity, the question would be... do the evanescent waves carry that increased spin and momentum imparting it into the small end? Let's not forget that an evanescent wave is a weird duck that is now only beginning to be understood.
I think it's entirely possible to pump up a photon and accelerate it towards the end of the cavity right at the mode decay. Will it violate CoM if the now massive photon imparts motion and apparent thrust in the small end direction? No. What if I take those pumped up photons before I hit the endplate and decay them into evanescent waves which can't backscatter back into the large end which is the action that Conservation of Momentum uses. Added: When a photon is emitted or absorbed, it transfers h bar of angular momentum and the associated energy is also transferred.
This is one reason I wanted the tuning chamber in the small end. And I like X_ray's idea of the trap and I can insert a probe into it to monitor energy conditions.
Reading two papers right now and here is one of my favorite things cropping up with the Golden Ratio....
"The universality of this phenomenon is revealed by analyzing, in detail, the cases corresponding to a) total internal reflection (TIR) b) waveguides c)optical fibers d) surface electromagnetic waves. We also show the existence of a unique criterion in TIR (”golden
ratio condition”) " http://arxiv.org/abs/1504.06361
And the other which is kind of interesting...
http://onlyspacetime.com/QM-Foundation.pdf
I'm going to finish these up and clean up the mess I have in the shop (it wasn't me!).
I still need a Krell brain boost! To heck with those pesky monsters from the Id.
Shell
just added a thought...
I'm assuming your pre-prep includes squared paper and calibration marks denoting actual mg-wt.Close, I'm going to play around with it a bit on tuesday morning to get the best results. Probably use another pinhole in front of the laser and a vertical alignment of pinholes, every mm, on a black target...then video from behind. I'll add calibrated weights to the beam and note deflection. I like shell's bar-graph analogy. My gut feel is resolution of only about 10 mg or so for this home-brew setup. Actually, force in this region is of lettle interest to me anyway.
Try a normal mirror and a pinhole lens in front of the laser, you'll get a very nice laser dot with little or no fringing. I'm using the red laser I got off ebay (for like 20 bucks I got 3, red, green and blue (more like UV visible)). The red shows up in the video better BTW.I'm assuming your pre-prep includes squared paper and calibration marks denoting actual mg-wt.Close, I'm going to play around with it a bit on tuesday morning to get the best results. Probably use another pinhole in front of the laser and a vertical alignment of pinholes, every mm, on a black target...then video from behind. I'll add calibrated weights to the beam and note deflection. I like shell's bar-graph analogy. My gut feel is resolution of only about 10 mg or so for this home-brew setup. Actually, force in this region is of lettle interest to me anyway.
Good stuff. I reckon your chief artifactual source is going to be convective thermal in nature. It's tough to provide an estimate of its magnitude.Yes, there is a 12 in square copper board directly above the magnetron, where heat will rise around it. This is about the only variable to contend with as I've tried to use non magnetic materials on the fulcrum. Any downward force will be working agains this lift. So if I see anything, I'll invert the engine, measure upwards force then subtract the difference. This should approximate thermal lift.
SeeShells et al. A short distance from Fermilab is a good source for strange bits of scientific surplus and junk. Lots of odd front surface mirror bits, pin holes and the like. http://www.sciplus.com/ (http://www.sciplus.com/)ACK! Be back after I dig through it. Love it, I'm a kid in a candy store!
JBtek® HDMI / VGA Digital LCD Driver Board with 9" TFT LCD for Raspberry PiI'd love to see some pics or vids of your work in progress. C'mon, shell...jump in, the water's fine.
DEWALT DW5576 3/8-Inch Diamond Drill Bit 2 Arriving today by 8pm
compass magnetometer IC, I2C, HMC5883L, PCB module, for Arduino microcontroller
( 141332300714 )
Estimated delivery Mon, Aug 24 - Mon, Aug 31
Got the XYZ accelerometer already.
Seems like it's taking forever! I'm getting so antsy to test!
Shell
Ok will do. I'll get my camera back from a friend who borrowed it for wedding pics this weekend and take some for ya. News and pics at 9. ;)JBtek® HDMI / VGA Digital LCD Driver Board with 9" TFT LCD for Raspberry PiI'd love to see some pics or vids of your work in progress. C'mon, shell...jump in, the water's fine.
DEWALT DW5576 3/8-Inch Diamond Drill Bit 2 Arriving today by 8pm
compass magnetometer IC, I2C, HMC5883L, PCB module, for Arduino microcontroller
( 141332300714 )
Estimated delivery Mon, Aug 24 - Mon, Aug 31
Got the XYZ accelerometer already.
Seems like it's taking forever! I'm getting so antsy to test!
Shell
NSF-1701 on fulcrum ready to flight test: https://youtu.be/XQ5HOYeJf4YLooks very nice :)
I had a blast doing the flights and would go again in a heartbeat. We had 30+ people on the plane for 4 flight days and nobody got sick.
To test a free-flying object in the plane you have to release it near the center-line of the vehicle once the zero G is established. No way you'd want to try that with 100kg!! Needs to be more like 10... And you don't get the full 20 seconds for a free-flyer. Remember, you're really in a plane that's falling out of the sky, controlled by a pilot. They have to actively try to fly the fuselage around the centerline of the mass, but they will tend to drift a bit, so your device will - no matter how carefully you release it - drift toward one of the walls and eventually impact it. 10-15 seconds is what you actually get before touching the wall/ceiling/floor. And then you have to catch the device and lower it to the floor as the pilot pulls up (the gravity comes back 'on' somewhat gradually, 3-5 seconds). So again the 100kg is too much for a free-flyer.
Maybe if you constrained it to fly down a tube...but then the tube has to have all kinds of safety constraints (they're really picky about safety obviously!). It's a hard problem, one I'd LOVE to work on!! :)
If you could get the device to behave that way in parabolic flight, why could you not measure the thrust of the same device in the lab? What effect are we eliminating by putting in in free fall? Why not just put it on a air bearing floor?
I'm not up to the task of the maths to calculate out the equations and I would leave that to others who are much better at it them me. I guess the thing would be how would I test for that effect so I could supply good data?I like this thought somewhat. More than once I've seen the relationship between this cavity and a particle accelerator. (Warning Warning Will Robinson, Engineer thinking physics alert)More on photon "mass" within waveguides:
http://iopscience.iop.org/1063-7869/40/3/A05
These ain't your usual garden variety photons when they get confined it seems.
AFAIK, confined particles are represented by standing waves. Vice versa, any standing wave is then equivalent to a confined particle including properties such as mass etc. Depending on chosen mode(s), the standing wave distribution within the waveguide could then represent not just one single confined particle, but actually a sort of atomic lattice of dynamically created massive particle equivalents. Following this line of thought, there is maybe an optimal standing wave distribution within any waveguide that maximizes this effect, i.e. creating a maximally massive particle equivalent.
If I understood Dr. Rodal correctly, then there is only an observable stress/force imbalance if the RF feed is on? I'm getting the impression that what's actually happening in this device is this:
- Incoming RF energy creates standing wave distributions, which are equivalent to confined massive particles within the waveguide
- Depending on the standing wave distributions, they represent an actual massive particle structure with varying topology
- If this massive particle structure can be regarded as an actual massive confined particle structure, then the Heisenberg uncertainty principle should apply, too (as does for any other real particle, no matter if (pseudo) static or dynamic)
- Since the location as well as the impulse of this particle structure are smeared according to Heisenberg, this dynamical particle structure statistically squeezes more against the smaller waveguide end volume than it squeezes against the larger waveguide end volume or (!) vice versa - depending on the topology of the dynamically created mode dependent massive particle structure
- This squeeze stress shows up as a real net force against the small end or (!) the large end, depending on mode dependent particle structure topology
- The imbalanced Heisenberg squeeze-stress-imparted impulse on the waveguide finds its balance by energy conversion into heat (= chaotic local impulse) within the waveguide's crystal lattice
- The active RF feed is like a lifeline to the dynamic process of creating and upholding an energy delta that gives the confined particle structure its 'life'.
- I'm sure that MEEP is not made to take Heisenberg's uncertainty principle into consideration when simulating Maxwell's equations. Wherever the dynamic particle structure is squeezed within a real cavity .. EM stress and forces are bound to come into existence. This might be key to understand what's happening here.
At least that's how my naive engineering mind imagines what's going on. Comments are welcome :) .
Let's see, if the mode . . .
"creates standing wave distributions, which are equivalent to confined massive particles within the waveguide
- Depending on the standing wave distributions, they represent an actual massive particle structure with varying topology
- If this massive particle structure can be regarded as an actual massive confined particle structure, then the Heisenberg uncertainty principle should apply, too (as does for any other real particle, no matter if (pseudo) static or dynamic)"
And then during a mode switch (which happens withing the cavity) it promptly decays into an evanescent wave into the small end of the cavity, the question would be... do the evanescent waves carry that increased spin and momentum imparting it into the small end? Let's not forget that an evanescent wave is a weird duck that is now only beginning to be understood.
I think it's entirely possible to pump up a photon and accelerate it towards the end of the cavity right at the mode decay. Will it violate CoM if the now massive photon imparts motion and apparent thrust in the small end direction? No. What if I take those pumped up photons before I hit the endplate and decay them into evanescent waves which can't backscatter back into the large end which is the action that Conservation of Momentum uses. Added: When a photon is emitted or absorbed, it transfers h bar of angular momentum and the associated energy is also transferred.
This is one reason I wanted the tuning chamber in the small end. And I like X_ray's idea of the trap and I can insert a probe into it to monitor energy conditions.
Reading two papers right now and here is one of my favorite things cropping up with the Golden Ratio....
"The universality of this phenomenon is revealed by analyzing, in detail, the cases corresponding to a) total internal reflection (TIR) b) waveguides c)optical fibers d) surface electromagnetic waves. We also show the existence of a unique criterion in TIR (”golden
ratio condition”) " http://arxiv.org/abs/1504.06361
And the other which is kind of interesting...
http://onlyspacetime.com/QM-Foundation.pdf
I'm going to finish these up and clean up the mess I have in the shop (it wasn't me!).
I still need a Krell brain boost! To heck with those pesky monsters from the Id.
Shell
just added a thought...
I'm trying to see a mode conversion in the flat ends cavity, and associated with that a electromagnetic center of mass oscillation.
A spatial oscillation of fields energy distribuition is a scenarium of the called bloch wave oscillation wich arises in some configurations of gain/loss Spatial symmetry ( PT symmetry) plus a "linear potential" ( a gradient of contitutives properties of medium).
A oscillation of center of mass can be viewd as a oscillation of rest reference frame too, and like a foucault pendulum where occurs a rotation of oscilattion plane because of a berry phase, I'm curious if there is a berry phase causing a lorentz boost ( a space-time hyperbolic rotation).
But both, PT symmetry breaking (hamiltonian exceptional points study), and berry phases ( topological momentum space curvature effects) has a very hard math description.
I had a blast doing the flights and would go again in a heartbeat. We had 30+ people on the plane for 4 flight days and nobody got sick.
...
Maybe if you constrained it to fly down a tube...but then the tube has to have all kinds of safety constraints (they're really picky about safety obviously!). It's a hard problem, one I'd LOVE to work on!! :)
Ok, I understand that it could be really difficult to get any accurate displacement measurement in vaccuum during a parabolic flight.If you could get the device to behave that way in parabolic flight, why could you not measure the thrust of the same device in the lab? What effect are we eliminating by putting in in free fall? Why not just put it on a air bearing floor?
I agree that in principle the initial thrust can be measured on a static test bench. But I would like to measure precisely how this thrust varies when the speed of the cavity increases under its action. There is a strong rationale to think that the thrust should decrease (or the RF power consumption of the cavity increase ...) when the speed increases.
For what concern the use of a air bearing floor, I suppose that it entails to operate at ambiant pressure and that the unevitable air resistance would too much perturbate the dynamic of the experience.
Tried to call her but no answer, her husbands friend said they took off to Blackhawk Casino, Colorado on Sunday. Sigh... Want to bet they are still in bed sleeping... or not? ;)Ok will do. I'll get my camera back from a friend who borrowed it for wedding pics this weekend and take some for ya. News and pics at 9. ;)JBtek® HDMI / VGA Digital LCD Driver Board with 9" TFT LCD for Raspberry PiI'd love to see some pics or vids of your work in progress. C'mon, shell...jump in, the water's fine.
DEWALT DW5576 3/8-Inch Diamond Drill Bit 2 Arriving today by 8pm
compass magnetometer IC, I2C, HMC5883L, PCB module, for Arduino microcontroller
( 141332300714 )
Estimated delivery Mon, Aug 24 - Mon, Aug 31
Got the XYZ accelerometer already.
Seems like it's taking forever! I'm getting so antsy to test!
Shell
Shell
Tried to call her but no answer, her husbands friend said they took off to Blackhawk Casino, Colorado on Sunday. Sigh... Want to bet they are still in bed sleeping... or not? ;)Ok will do. I'll get my camera back from a friend who borrowed it for wedding pics this weekend and take some for ya. News and pics at 9. ;)JBtek® HDMI / VGA Digital LCD Driver Board with 9" TFT LCD for Raspberry PiI'd love to see some pics or vids of your work in progress. C'mon, shell...jump in, the water's fine.
DEWALT DW5576 3/8-Inch Diamond Drill Bit 2 Arriving today by 8pm
compass magnetometer IC, I2C, HMC5883L, PCB module, for Arduino microcontroller
( 141332300714 )
Estimated delivery Mon, Aug 24 - Mon, Aug 31
Got the XYZ accelerometer already.
Seems like it's taking forever! I'm getting so antsy to test!
Shell
Shell
And no my cell can't do pics. My cell phone is so outdated, I still have a rotary dial on it.
Shell
Got the endplate piston from Jo today. Here´s the assembled cavity.
I got a question for the microwave professionals: There is a small gap between the endplate piston and the cavity walls. What will this mean for the wave propagation?
The piston might touch the cavity on one side. Should I better isolate the cavity wall from the piston, or should it somehow contact the cavity on all sides?
Paul Kocyla (@movax on Hackaday.io) just assembled the new Silver baby-EmDrive cavity today and has some questions:The question is which mode he like to drive.
New Cavity Assembled (https://hackaday.io/project/5596-em-drive/log/23996-new-cavity-assembled)Quote from: Paul KocylaGot the endplate piston from Jo today. Here´s the assembled cavity.
I got a question for the microwave professionals: There is a small gap between the endplate piston and the cavity walls. What will this mean for the wave propagation?
The piston might touch the cavity on one side. Should I better isolate the cavity wall from the piston, or should it somehow contact the cavity on all sides?
Re rfmwguy Post #991Very cool, thanks...might use this down the road if I continue the project.
If you are still looking for HV wire, McMaster-Carr has plenty:
http://www.mcmaster.com/#high-voltage-wire/=ymwsh6
It starts at 10 KV rating, goes up to 42 KV, and is available in pieces as short as 5' @ under $2/ft for the lower voltage/smaller conductor stuff. At 4 KV, I wouldn't expect you would need a very large conductor to handle the magnetron current.
I can only guess about 5% lower resonance, or about 2.2 to 2.3 GHzNSF-1701 on fulcrum ready to flight test: https://youtu.be/XQ5HOYeJf4YLooks very nice :)
Do you have an idea how the current resonance frequency of your target mode is with the spherical copper mesh? (How much lower compared with the flat as calculated before?)
Paul Kocyla (@movax on Hackaday.io) just assembled the new Silver baby-EmDrive cavity today and has some questions:Contact, no gaps especially @ 25 GHz is my 2 cents.
New Cavity Assembled (https://hackaday.io/project/5596-em-drive/log/23996-new-cavity-assembled)Quote from: Paul KocylaGot the endplate piston from Jo today. Here´s the assembled cavity.
I got a question for the microwave professionals: There is a small gap between the endplate piston and the cavity walls. What will this mean for the wave propagation?
The piston might touch the cavity on one side. Should I better isolate the cavity wall from the piston, or should it somehow contact the cavity on all sides?
Paul Kocyla (@movax on Hackaday.io) just assembled the new Silver baby-EmDrive cavity today and has some questions:The question is which mode he like to drive.
New Cavity Assembled (https://hackaday.io/project/5596-em-drive/log/23996-new-cavity-assembled)Quote from: Paul KocylaGot the endplate piston from Jo today. Here´s the assembled cavity.
I got a question for the microwave professionals: There is a small gap between the endplate piston and the cavity walls. What will this mean for the wave propagation?
The piston might touch the cavity on one side. Should I better isolate the cavity wall from the piston, or should it somehow contact the cavity on all sides?
There are big differences between the fields and currents through the gap for different mode shapes!
Was already discussed here:
http://forum.nasaspaceflight.com/index.php?topic=38203.msg1418675#msg1418675
http://forum.nasaspaceflight.com/index.php?topic=38203.msg1418696#msg1418696
http://forum.nasaspaceflight.com/index.php?topic=38203.msg1418939#msg1418939
We want to permutate all possible parameters of the EMdrive, which means many positions of the small endplate and a wide frequency spectrum 23-25 GHz. The tests will be run automatically. So there is no specific mode planned
There was a coupling loop on an EW pic behind the HDPE. It was abt 3.5 cm from edge, which is where mine is.
If you mean this internal picture, the loop was near the 280 mm big base:
(http://forum.nasaspaceflight.com/xindex.php,qaction=dlattach,3Btopic=38203.0,3Battach=1057032,3Bimage.pagespeed.ic.AwGtB_pjPB.jpg)
I work in the K-band (18–26,5 GHz) with conical cavities some years till now! With a silver plated cavity the resonance bandwidth is to small for overlapping more than 2..3 modes and even this is only random or a tuning problem!Paul Kocyla (@movax on Hackaday.io) just assembled the new Silver baby-EmDrive cavity today and has some questions:The question is which mode he like to drive.
New Cavity Assembled (https://hackaday.io/project/5596-em-drive/log/23996-new-cavity-assembled)Quote from: Paul KocylaGot the endplate piston from Jo today. Here´s the assembled cavity.
I got a question for the microwave professionals: There is a small gap between the endplate piston and the cavity walls. What will this mean for the wave propagation?
The piston might touch the cavity on one side. Should I better isolate the cavity wall from the piston, or should it somehow contact the cavity on all sides?
There are big differences between the fields and currents through the gap for different mode shapes!
Was already discussed here:
http://forum.nasaspaceflight.com/index.php?topic=38203.msg1418675#msg1418675
http://forum.nasaspaceflight.com/index.php?topic=38203.msg1418696#msg1418696
http://forum.nasaspaceflight.com/index.php?topic=38203.msg1418939#msg1418939
I know, that's why I asked him which mode he wants to excite, but he doesn't know. He specifically answered (https://hackaday.io/project/5596-em-drive/log/23696-silver-cavity-arrived/discussion-33428) last weeek:Quote from: Paul KocylaWe want to permutate all possible parameters of the EMdrive, which means many positions of the small endplate and a wide frequency spectrum 23-25 GHz. The tests will be run automatically. So there is no specific mode planned
But at such a small size, several modes could overlap near the same frequency, for example TE013, TE114 and TM113.
BTW his antenna is a 1/4 lambda stub of 24 GHz, located near the small end.
Tell him the can contact me in germany if he like to do so. (first time via PM here)Thanks for him! Paul will contact you soon :)
Anyone else keep having great ideas and insight (mostly while daydreaming and dreaming) only to forget what it was? I dream of photons and copper cans every night.This is very common: I have books by famous scientists like Poincare, Duhem and others, as well as articles written by mathematician's, physicists, and inventors that some of the best ideas (their aha!) moments often come during dreams. Many of them kept a notebook by their bed to write down their ideas as soon as awake, in order not to forget them. Our unconscious mind keeps thinking about problems while we are asleep.
In vacuum? On an airplane? No way. That's essentially a pressure vessel, no way they'd let that on a plane - way too dangerous. Free-flying in a vacuum requires a spaceflight.
Have to confess, I did a test firing this AM. No arcs on terminal. Humidity was low. Will measure that on Tuesday. Yes, I'm avoiding anything next to hv insulation. Proper wire for this is silicone insulated...like on oscilloscope test lead, only heavier guage. Could not locate easily.(video snip)
Can you set up a second camera watching the frustum and rig while the first looks at the paper? Not perfect, but the first thing I'd think of with the camera only recording the laser moving is that you might be physically manipulating the rig. Given that the lights are going to be off, I realize that this would be difficult. Maybe some form of thermal camera? Then again I can understand just wanting the verify that the thing is giving some kind of detectable result before fiddling with it more.
I have a suggestion that might Kill three birds with one stone rfmwguy.
Take your camera and shoot the backside of the graph paper. Easier for your camera to see the red dot without blossoming out from sensitivity to the red light.
You can see the device and the paper in one view if it's set up right.
On the front of the paper run two strips of electrical tape up and down separated by a small gap maybe 1/4 inch. It will help define the movement. Like a vertical bar graph display and make your lines heavy horizontally when you do the graph paper.
One other thing, twist the power leads together and the heater leads together, you'll reduce noise and cancel AC effects the leads may carry.
I also suggested twisting the leads, but I'm not sure the insulation on the red wire is actually 4000V rated. If not, don't do it, it may breakdown through to the other wires. I'm not sure that terminal block is good for 4000V either. Humidity may cause it to arc to ground.
Todd
In vacuum? On an airplane? No way. That's essentially a pressure vessel, no way they'd let that on a plane - way too dangerous. Free-flying in a vacuum requires a spaceflight.
The NASA drop tube that I have indicated operates in vacuum condition.
For the plane and its parabolic trajectory I have suggested the use of a small vacuum chamber around the test device (I agree... nothing afraid me :) ). But I understand that even if the plane can flight with this test set up, it is impossible to insure that the test device will not hurt the walls of the vacuum chamber. So we forget this idea ...
Remains the possibility of a test within the vacuum drop tube. Now, are 5.3 seconds of free fall time sufficient to measure a thrust variation ? This is an open question.
Doc, can yuo give me the url of paul march's folder again? Thanks...There was a coupling loop on an EW pic behind the HDPE. It was abt 3.5 cm from edge, which is where mine is.
If you mean this internal picture, the loop was near the 280 mm big base:
(http://forum.nasaspaceflight.com/xindex.php,qaction=dlattach,3Btopic=38203.0,3Battach=1057032,3Bimage.pagespeed.ic.AwGtB_pjPB.jpg)
I have gone over and checked all the data posted at NSF by Paul March and I fully agree: the NASA Eagleworks copper truncated cone has an antenna mounted on the frustum sidewall approximately 15% of the frustum’s 9.00” length, (~1.35” or 3.43cm), up from the Big Base of the cavity as shown in the image in your post and as shown in their AIAA Brady et.al report.
This is very crucial because NASA's test (which in my opinion are the most trustworthy tests) have been run with the antenna near the Big End.
Thus NASA's tests are in agreement with the Meep computer runs, post-processed with Wolfram Mathematica ( http://forum.nasaspaceflight.com/index.php?topic=38203.msg1418516#msg1418516 ) to analyze the stress tensor and forces that show that it is only when the antenna is located near the Big End that the there is an imbalance of forces pointing towards the small end that cannot be overcome by the reactions from the forces on the side-walls. When the antenna is placed near the small end, the forces from the side wall can overcome the force towards the big end and result in no net force on the truncated cone.
I look forward to RFMWGUY's test with the magnetron at the small end to see what he finds :)
Doc, nevermind. I found the original EW pic showing the drive antenna on the small end.
This is where I suspect Mr. March was going. Also he had a top-mounted 100 kW Magnetron on a concept drawing.
Its a year after your other pic.
Correction, the drive antenna was in front of the dielectric. Strange looking HDPE, almost looks infused with graphene ;)
In vacuum? On an airplane? No way. That's essentially a pressure vessel, no way they'd let that on a plane - way too dangerous. Free-flying in a vacuum requires a spaceflight.
The NASA drop tube that I have indicated operates in vacuum condition.
For the plane and its parabolic trajectory I have suggested the use of a small vacuum chamber around the test device (I agree... nothing afraid me :) ). But I understand that even if the plane can flight with this test set up, it is impossible to insure that the test device will not hurt the walls of the vacuum chamber. So we forget this idea ...
Remains the possibility of a test within the vacuum drop tube. Now, are 5.3 seconds of free fall time sufficient to measure a thrust variation ? This is an open question.
Could not locate docs on performance related to this specific version. It just seemed it was later than shawyers loop design and only one I could confirm had a dielectric.Doc, nevermind. I found the original EW pic showing the drive antenna on the small end.
This is where I suspect Mr. March was going. Also he had a top-mounted 100 kW Magnetron on a concept drawing.
Its a year after your other pic.
Correction, the drive antenna was in front of the dielectric. Strange looking HDPE, almost looks infused with graphene ;)
I had forgotten about that design. If my memory serves me correctly, he wrote that they got bad thrust results with that design.
At the time of the discussion we were not running Meep and hence the issue of the antenna location did not come up.
Perhaps the reason why they got bad results has everything to do with the fact that the antenna was at the small end :)
I had a blast doing the flights and would go again in a heartbeat. We had 30+ people on the plane for 4 flight days and nobody got sick.
...
Maybe if you constrained it to fly down a tube...but then the tube has to have all kinds of safety constraints (they're really picky about safety obviously!). It's a hard problem, one I'd LOVE to work on!! :)
Ok, I understand that it could be really difficult to get any accurate displacement measurement in vaccuum during a parabolic flight.If you could get the device to behave that way in parabolic flight, why could you not measure the thrust of the same device in the lab? What effect are we eliminating by putting in in free fall? Why not just put it on a air bearing floor?
I agree that in principle the initial thrust can be measured on a static test bench. But I would like to measure precisely how this thrust varies when the speed of the cavity increases under its action. There is a strong rationale to think that the thrust should decrease (or the RF power consumption of the cavity increase ...) when the speed increases.
For what concern the use of a air bearing floor, I suppose that it entails to operate at ambiant pressure and that the unevitable air resistance would too much perturbate the dynamic of the experience.
In vacuum? On an airplane? No way. That's essentially a pressure vessel, no way they'd let that on a plane - way too dangerous. Free-flying in a vacuum requires a spaceflight.
Brain is locked into loop...
I keep thinking about building the best way to have "clean" resonance patterns by using a one way material, that is "transparent" to microwaves from one side and not from the other.
It would allow the wave guides to be placed at the big or small end (needs to be tested?) and result in very clean internal patterns, even odd shaped ones like trumpet/horn shaped ones.
Technical/scientific English is often an obstacle for me, but i did manage to find a few potential interesting articles. Comprehending what's written, that's another turf...
anyway...the magical words seem to be : nonreciprocal meta-materials. I just cant picture any real material, or find where you - potentially - could buy it....
http://journals.aps.org/prb/abstract/10.1103/PhysRevB.85.205101
http://ieeexplore.ieee.org/xpl/login.jsp?tp=&arnumber=6565764&url=http%3A%2F%2Fieeexplore.ieee.org%2Fiel7%2F6558537%2F6565651%2F06565764.pdf%3Farnumber%3D6565764
http://people.ee.duke.edu/~cummer/ElectromagneticMetamaterials.html
Could not locate docs on performance related to this specific version. It just seemed it was later than shawyers loop design and only one I could confirm had a dielectric.
(Edit) also note the correct way to measure Q ...2 port.
Dr. Rodal & Crew:
The Eagleworks team has already build a 6061 aluminum frustum cavity with 1/4" thick walls and O-ring end caps meant to hold a 1 Bar pressure differential with internal nickel/copper/silver/gold plating system on all interior surfaces with plating thickness of 10-to-15 microns for the first three layers and 0.5 microns for exposed to the RF gold layer. Sadly the gold layer was just as thick as the rest of the plated layers and textured as well, so as far as the applied ~2.0 GHz RF was concerned it was only interacting with the rough gold layer. This had the effect of cutting the resonant Q-factor for this aluminum frustum by almost a factor of three over our copper frustum for the resonances of interest.
At the same time we also tried using a smaller volume, higher-K (e-r=~40) ceramic dielectric resonator discs in the Al cavity mounted at its small OD end, while driving it at its TE011 mode if memory serves. Bottom line was that this configuration was a total bust in regards to thrust production in our torque pendulum system running at this resonant mode. This aluminum frustum design also turned out to be ~4X times the mass of the thin walled copper cavity even while using lower density aluminum for its construction. This exercise was a tribute to the fact that one should never ASSUME that you know what you are doing until proven otherwise! And oh yes, and only try one variation in the design at a time or one will get lost, fast!
Best, Paul M.
A couple of models using SeeShell's (and Rodal's) dimensions posted earlier.
Dimensions in both cases are:
bigDiameter = 0.295(*meter*);
smallDiameter = 0.160(*meter*);
axialLength = 0.163(*meter*);
These dimensions on the model with spherical ends are exactly the same. The dimensions of the spherical ends are:
r1= 0.20114 m (*small spherical radius*)
r2= 0.370852 m (*big spherical radius*)
theta = 22.495 degrees (*half cone angle*)
These spherical segments match exactly to the conic section. Note that the axial length is the axial length of the conic section and is not the difference in the radial distance between the two spherical sections. That distance is r2 - r1 = 0.370852 m - 0.20114 m. In the meep model shown, r2 is the inside radius of the big end spherical section while r1 is the outside radius of the small end spherical section.
...
@Dr. Rodal and others
In reference to Dr. Rodal's post here:
http://forum.nasaspaceflight.com/index.php?topic=38203.msg1418516#msg1418516
Is it possible that at this stage of actual EM Drive builds and their resulting test data ("In the public domain"). That computer based modeling might not yet include all required factors as input data to produce accurate estimates in their output data? Of all classical physics theories which could be involved, prove outside classical theories are involved or even if there are combinations of both currently taking place.
If somehow this becomes more apparent ("In the soon to be near future") that current computer modeling can't currently accurately account for the total results when those specifications are used for actual EM Drive builds. Then what's next?
Should things like internal photography and video inside cavities be used, magnetic fields and other recording and sensing devices be used in the future, during the testing of EM Drive builds?
I would like to hear what others suggested plan B's are out there to be considered if and when current computer models fail miserably to make accurate estimates. I would think others would as well.
Would you mostly all have similar plan B suggestions?
Especially with new EM Drive builds about to prove or disprove the accuracy of current computer models being used as being reasonably solid or in need of some major "Code changes" that might not even have the required mathematical formulas yet to be able to implement those "Code changes".
Don
@TheTraveller. I asked this while I think you were away. Do you have any suggestions?@Dr. Rodal and others
In reference to Dr. Rodal's post here:
http://forum.nasaspaceflight.com/index.php?topic=38203.msg1418516#msg1418516
Is it possible that at this stage of actual EM Drive builds and their resulting test data ("In the public domain"). That computer based modeling might not yet include all required factors as input data to produce accurate estimates in their output data? Of all classical physics theories which could be involved, prove outside classical theories are involved or even if there are combinations of both currently taking place.
If somehow this becomes more apparent ("In the soon to be near future") that current computer modeling can't currently accurately account for the total results when those specifications are used for actual EM Drive builds. Then what's next?
Should things like internal photography and video inside cavities be used, magnetic fields and other recording and sensing devices be used in the future, during the testing of EM Drive builds?
I would like to hear what others suggested plan B's are out there to be considered if and when current computer models fail miserably to make accurate estimates. I would think others would as well.
Would you mostly all have similar plan B suggestions?
Especially with new EM Drive builds about to prove or disprove the accuracy of current computer models being used as being reasonably solid or in need of some major "Code changes" that might not even have the required mathematical formulas yet to be able to implement those "Code changes".
Don
Don
If 700W pumping in does not do something then we are looking at very tight tolerances indeed - something that TT (welcome back!) and Shell are gearing up for.
Good stuff. I reckon your chief artifactual source is going to be convective thermal in nature. It's tough to provide an estimate of its magnitude.Yes, there is a 12 in square copper board directly above the magnetron, where heat will rise around it. This is about the only variable to contend with as I've tried to use non magnetic materials on the fulcrum. Any downward force will be working agains this lift. So if I see anything, I'll invert the engine, measure upwards force then subtract the difference. This should approximate thermal lift.
@TheTraveller. I asked this while I think you were away. Do you have any suggestions?@Dr. Rodal and others
In reference to Dr. Rodal's post here:
http://forum.nasaspaceflight.com/index.php?topic=38203.msg1418516#msg1418516
Is it possible that at this stage of actual EM Drive builds and their resulting test data ("In the public domain"). That computer based modeling might not yet include all required factors as input data to produce accurate estimates in their output data? Of all classical physics theories which could be involved, prove outside classical theories are involved or even if there are combinations of both currently taking place.
If somehow this becomes more apparent ("In the soon to be near future") that current computer modeling can't currently accurately account for the total results when those specifications are used for actual EM Drive builds. Then what's next?
Should things like internal photography and video inside cavities be used, magnetic fields and other recording and sensing devices be used in the future, during the testing of EM Drive builds?
I would like to hear what others suggested plan B's are out there to be considered if and when current computer models fail miserably to make accurate estimates. I would think others would as well.
Would you mostly all have similar plan B suggestions?
Especially with new EM Drive builds about to prove or disprove the accuracy of current computer models being used as being reasonably solid or in need of some major "Code changes" that might not even have the required mathematical formulas yet to be able to implement those "Code changes".
Don
Don
My computer model is based on advise from Shawyer.
It can search for resonance in 16 different modes and predicts Force generation from inputted cavity Q and power, assuming an Rf feed coupling factor of 1. It will shortly predict cavity Q, from inputted wall material choice and operational temperature.
It will also shortly suggests where the internal nodes & lobes for the chosen resonant modes are located along the frustum side wall.
If 700W pumping in does not do something then we are looking at very tight tolerances indeed - something that TT (welcome back!) and Shell are gearing up for.
If there is no significant resonance in a useful mode or if the antenna coupling factor is bad, then all that will happen is stuff will get warm.
@TheTraveller. I asked this while I think you were away. Meaning if computer modeling is not currently forecasting accurate thrust predictions. Should there be other things to start looking at/recording/monitoring, for EM Drive builders? So that better computer models can be used to also use that input data with factors contributing to thrust besides using only the current factors they are using now. If it comes to that? Do you have any suggestions?@Dr. Rodal and others
In reference to Dr. Rodal's post here:
http://forum.nasaspaceflight.com/index.php?topic=38203.msg1418516#msg1418516
Is it possible that at this stage of actual EM Drive builds and their resulting test data ("In the public domain"). That computer based modeling might not yet include all required factors as input data to produce accurate estimates in their output data? Of all classical physics theories which could be involved, prove outside classical theories are involved or even if there are combinations of both currently taking place.
If somehow this becomes more apparent ("In the soon to be near future") that current computer modeling can't currently accurately account for the total results when those specifications are used for actual EM Drive builds. Then what's next?
Should things like internal photography and video inside cavities be used, magnetic fields and other recording and sensing devices be used in the future, during the testing of EM Drive builds?
I would like to hear what others suggested plan B's are out there to be considered if and when current computer models fail miserably to make accurate estimates. I would think others would as well.
Would you mostly all have similar plan B suggestions?
Especially with new EM Drive builds about to prove or disprove the accuracy of current computer models being used as being reasonably solid or in need of some major "Code changes" that might not even have the required mathematical formulas yet to be able to implement those "Code changes".
Don
Don
A couple of models using SeeShell's (and Rodal's) dimensions posted earlier.
Dimensions in both cases are:
bigDiameter = 0.295(*meter*);
smallDiameter = 0.160(*meter*);
axialLength = 0.163(*meter*);
These dimensions on the model with spherical ends are exactly the same. The dimensions of the spherical ends are:
r1= 0.20114 m (*small spherical radius*)
r2= 0.370852 m (*big spherical radius*)
theta = 22.495 degrees (*half cone angle*)
These spherical segments match exactly to the conic section. Note that the axial length is the axial length of the conic section and is not the difference in the radial distance between the two spherical sections. That distance is r2 - r1 = 0.370852 m - 0.20114 m. In the meep model shown, r2 is the inside radius of the big end spherical section while r1 is the outside radius of the small end spherical section.
Doc, nevermind. I found the original EW pic showing the drive antenna on the small end.
This is where I suspect Mr. March was going. Also he had a top-mounted 100 kW Magnetron on a concept drawing.
Its a year after your other pic.
Correction, the drive antenna was in front of the dielectric. Strange looking HDPE, almost looks infused with graphene ;)
(http://forum.nasaspaceflight.com/xindex.php,qaction=dlattach,3Btopic=38203.0,3Battach=1059514,3Bimage.pagespeed.ic.evKgm4cx-R.webp)
The best thing is to use a loop antenna for TE modes
@TheTraveller. I asked this while I think you were away. Meaning if computer modeling is not currently forecasting accurate thrust predictions. Should there be other things to start looking at/recording/monitoring, for EM Drive builders? So that better computer models can be used to also use that input data with factors contributing to thrust besides using only the current factors they are using now. If it comes to that? Do you have any suggestions?@Dr. Rodal and others
In reference to Dr. Rodal's post here:
http://forum.nasaspaceflight.com/index.php?topic=38203.msg1418516#msg1418516
Is it possible that at this stage of actual EM Drive builds and their resulting test data ("In the public domain"). That computer based modeling might not yet include all required factors as input data to produce accurate estimates in their output data? Of all classical physics theories which could be involved, prove outside classical theories are involved or even if there are combinations of both currently taking place.
If somehow this becomes more apparent ("In the soon to be near future") that current computer modeling can't currently accurately account for the total results when those specifications are used for actual EM Drive builds. Then what's next?
Should things like internal photography and video inside cavities be used, magnetic fields and other recording and sensing devices be used in the future, during the testing of EM Drive builds?
I would like to hear what others suggested plan B's are out there to be considered if and when current computer models fail miserably to make accurate estimates. I would think others would as well.
Would you mostly all have similar plan B suggestions?
Especially with new EM Drive builds about to prove or disprove the accuracy of current computer models being used as being reasonably solid or in need of some major "Code changes" that might not even have the required mathematical formulas yet to be able to implement those "Code changes".
Don
Don
The current batch of physical tests will provide some very valuable information. The possibilities for cavity length, antenna placement and shape, input energy modes, computer automation and auto-tuning... there is a lot to explore.
I personally am in no doubt the current spreadsheets and/or privately held mathematical models do not contain anywhere near the full spectrum of events and actions happening in relation to the tests. Warptech is following the issue of the Gravitational-mimic field (keep going there mate, you have something important waiting at the end of this), there is also potential for interaction with other presently "mysterious fields" such as dark energy and/or dark matter which may somehow play a part as these are known to react to gravitational energy. The evanescent issues are interesting and may yet become an exploration in their own right. The whole spectrum of electron acceleration... will also come into play at some point. Then throw superconduction in there just to multiply complexity by 100x.
You are right to be concerned about the "What if" scenarios for expanding the test regime.. but for now... one step at a time. When this device is finished, then we can move on to the other
TT, welcome back, take care
The best thing is to use a loop antenna for TE modes
Ok then but how do you reconcile the need to put the loop antenna into the nodes of the mode (which are several centimeters apart) and the need for the loop antenna to have a perimeter equal to 1/4 wavelength (which gives a loop diameter of 3.5 to 4.5 cm)?
...As previously posted, the EM Drive to be tested today has the antenna located at the small end of the cavity, while the latest computer analysis indicates that the antenna should be located at the completely opposite location: near the opposite end, near the big base.
Please don't be offended but one of those EM Drives designed with help from computer models is scheduled to be tested "Today".
...
...As I posted several times, the EM Drive to be tested today has the antenna located at the small end of the cavity, while the analysis indicates it should be located at the completely opposite location: near the opposite end, near the big base.
Please don't be offended but one of those EM Drives designed with help from computer models is scheduled to be tested "Today".
...
The best thing is to use a loop antenna for TE modes
Ok then but how do you reconcile the need to put the loop antenna into the nodes of the mode (which are several centimeters apart) and the need for the loop antenna to have a perimeter equal to 1/4 wavelength (which gives a loop diameter of 3.5 to 4.5 cm)?
Don't put an antenna at a node. A node is location of zero amplitude. Instead locate the antenna at an anti-node: a location of maximum amplitude.
(http://www.antonine-education.co.uk/Image_library/Physics_2/Waves/Superposition/wav_26.gif)
The orientation of the loop antenna for a TE mode should be such that the magnetic field goes through the center of the loop. The magnetic field in TE01 modes is oriented along the longitudinal axis of axi-symmetry. Thus the perimeter of the antenna is perpendicular to the longitudinal axis and hence perpendicular to the longitudinal propagation direction of the wave.
We have to consider there are many ways to excite modes within the cavity and the general meep would need to be modified (which it can be) to work with them all. Dr. Rodel in taking the CSV files and post processing with mathematica is proving a very good workaround and has given us some very insightful data....As previously posted, the EM Drive to be tested today has the antenna located at the small end of the cavity, while the latest computer analysis indicates that the antenna should be located at the completely opposite location: near the opposite end, near the big base.
Please don't be offended but one of those EM Drives designed with help from computer models is scheduled to be tested "Today".
...
Thus today's test will be instructive to see what happens when the antenna is located in the opposite direction than the one recommended by the latest computer analysis and the opposite direction than the one used by NASA Eagleworks in their positive tests.
The best thing is to use a loop antenna for TE modes
Ok then but how do you reconcile the need to put the loop antenna into the nodes of the mode (which are several centimeters apart) and the need for the loop antenna to have a perimeter equal to 1/4 wavelength (which gives a loop diameter of 3.5 to 4.5 cm)?
Don't put an antenna at a node. A node is location of zero amplitude. Instead locate the antenna at an anti-node: a location of maximum amplitude.
(http://www.antonine-education.co.uk/Image_library/Physics_2/Waves/Superposition/wav_26.gif)
The orientation of the loop antenna for a TE mode should be such that the magnetic field goes through the center of the loop. The magnetic field in TE01 modes is oriented along the longitudinal axis of axi-symmetry. Thus the perimeter of the antenna is perpendicular to the longitudinal axis and hence perpendicular to the longitudinal propagation direction of the wave.
Fair enough, wrong terminology from my side. But my question is still valid for antinodes.
I wanted to talk about the centers of the blue or red "blobs" in Meep simulations.
The best thing is to use a loop antenna for TE modes
Ok then but how do you reconcile the need to put the loop antenna into the nodes of the mode (which are several centimeters apart) and the need for the loop antenna to have a perimeter equal to 1/4 wavelength (which gives a loop diameter of 3.5 to 4.5 cm)?
Don't put an antenna at a node. A node is location of zero amplitude. Instead locate the antenna at an anti-node: a location of maximum amplitude.
(http://www.antonine-education.co.uk/Image_library/Physics_2/Waves/Superposition/wav_26.gif)
The orientation of the loop antenna for a TE mode should be such that the magnetic field goes through the center of the loop. The magnetic field in TE01 modes is oriented along the longitudinal axis of axi-symmetry. Thus the perimeter of the antenna is perpendicular to the longitudinal axis and hence perpendicular to the longitudinal propagation direction of the wave.
Fair enough, wrong terminology from my side. But my question is still valid for antinodes.
I wanted to talk about the centers of the blue or red "blobs" in Meep simulations.
A Time Zone would be helpful 8)
Fingers crossed.
The best thing is to use a loop antenna for TE modes
Ok then but how do you reconcile the need to put the loop antenna into the nodes of the mode (which are several centimeters apart) and the need for the loop antenna to have a perimeter equal to 1/4 wavelength (which gives a loop diameter of 3.5 to 4.5 cm)?
Don't put an antenna at a node. A node is location of zero amplitude. Instead locate the antenna at an anti-node: a location of maximum amplitude.
(http://www.antonine-education.co.uk/Image_library/Physics_2/Waves/Superposition/wav_26.gif)
The orientation of the loop antenna for a TE mode should be such that the magnetic field goes through the center of the loop. The magnetic field in TE01 modes is oriented along the longitudinal axis of axi-symmetry. Thus the perimeter of the antenna is perpendicular to the longitudinal axis and hence perpendicular to the longitudinal propagation direction of the wave.
Fair enough, wrong terminology from my side. But my question is still valid for antinodes.
I wanted to talk about the centers of the blue or red "blobs" in Meep simulations.
Don't read to much into those blue or red "blobs" on the latest meep images. They are only there to show the antenna location. I cut the simulation off after only 6/10th of a cycle so we can see the antenna but nothing has yet reached the side or end walls. So the blobs are only the antenna. They are located where Harminv calculates the best resonance from the antenna/cavity combination, but that is a different run, different image.
Next post will be a link to unedited video of NSF-1701's flight test.
I believe in an earlier post he had indicated that T0 was 1400 EDT.A Time Zone would be helpful 8)
Fingers crossed.
Uhhhh ... 45 min from 1:15, or about now, whatever timezone you are in ... he seems to be in EDT
My concern is how could we reconcile such a large loop with the fact its perimeter should be equal to λ/4 to trigger resonance in the cavity (with lambda being between 12 and 15 cm)?
X_Ray, this is a simplified sketch of a loop antenna, for didactic popularization purpose ;) The important thing to consider is the location of the loop WRT the cavity walls, end plates and mode shape. For example the two horizontal rods could be build in such a way they would not electromagnetically interfere with the waves, unlike in the sketch.
My concern is how could we reconcile such a large loop with the fact its perimeter should be equal to λ/4 to trigger resonance in the cavity (with lambda being between 12 and 15 cm)?
X_Ray, this is a simplified sketch of a loop antenna, for didactic popularization purpose ;) The important thing to consider is the location of the loop WRT the cavity walls, end plates and mode shape. For example the two horizontal rods could be build in such a way they would not electromagnetically interfere with the waves, unlike in the sketch.
Excite in TE013 mode and put the loop in the middle lobe as I indicated earlier.
My concern is how could we reconcile such a large loop with the fact its perimeter should be equal to λ/4 to trigger resonance in the cavity (with lambda being between 12 and 15 cm)?
X_Ray, this is a simplified sketch of a loop antenna, for didactic popularization purpose ;) The important thing to consider is the location of the loop WRT the cavity walls, end plates and mode shape. For example the two horizontal rods could be build in such a way they would not electromagnetically interfere with the waves, unlike in the sketch.
Excite in TE013 mode and put the loop in the middle lobe as I indicated earlier.
Climbing to the second floor won't really change the problem.
(the "middle lobe" you want to use in TE013 is barely smaller than the lower lobe, hence a loop perimeter barely smaller than what I draw, and still longer than λ/4)
To excite TE01 you need to excite a magnetic field in the longitudinal direction of the axis of axi-symmetry. If you want to keep the loop perimeter λ/4, what prevents one from making a loop λ/4 perimeter and placing it so that its center goes through the axis of axi-symmetry?My concern is how could we reconcile such a large loop with the fact its perimeter should be equal to λ/4 to trigger resonance in the cavity (with lambda being between 12 and 15 cm)?
X_Ray, this is a simplified sketch of a loop antenna, for didactic popularization purpose ;) The important thing to consider is the location of the loop WRT the cavity walls, end plates and mode shape. For example the two horizontal rods could be build in such a way they would not electromagnetically interfere with the waves, unlike in the sketch.
Excite in TE013 mode and put the loop in the middle lobe as I indicated earlier.
Climbing to the second floor won't really change the problem.
(the "middle lobe" you want to use in TE013 is barely smaller than the lower lobe, hence a loop perimeter barely smaller than what I draw, and still longer than λ/4)
My concern is how could we reconcile such a large loop with the fact its perimeter should be equal to λ/4 to trigger resonance in the cavity (with lambda being between 12 and 15 cm)?
X_Ray, this is a simplified sketch of a loop antenna, for didactic popularization purpose ;) The important thing to consider is the location of the loop WRT the cavity walls, end plates and mode shape. For example the two horizontal rods could be build in such a way they would not electromagnetically interfere with the waves, unlike in the sketch.
Excite in TE013 mode and put the loop in the middle lobe as I indicated earlier.
Climbing to the second floor won't really change the problem.
(the "middle lobe" you want to use in TE013 is barely smaller than the lower lobe, hence a loop perimeter barely smaller than what I draw, and still longer than λ/4)
You are right with the length of the wire, this could trigger other modes(field vectors along the wire). But:The best thing is to use a loop antenna for TE modes
Ok then but how do you reconcile the need to put the loop antenna into the nodes of the mode (which are several centimeters apart) and the need for the loop antenna to have a perimeter equal to 1/4 wavelength (which gives a loop diameter of 3.5 to 4.5 cm)?
Don't put an antenna at a node. A node is location of zero amplitude. Instead locate the antenna at an anti-node: a location of maximum amplitude.
(http://www.antonine-education.co.uk/Image_library/Physics_2/Waves/Superposition/wav_26.gif)
The orientation of the loop antenna for a TE mode should be such that the magnetic field goes through the center of the loop. The magnetic field in TE01 modes is oriented along the longitudinal axis of axi-symmetry. Thus the perimeter of the antenna is perpendicular to the longitudinal axis and hence perpendicular to the longitudinal propagation direction of the wave.
Fair enough, wrong terminology from my side. But my question is still valid for antinodes.
I wanted to talk about the centers of the blue or red "blobs" in Meep simulations.
Don't read to much into those blue or red "blobs" on the latest meep images. They are only there to show the antenna location. I cut the simulation off after only 6/10th of a cycle so we can see the antenna but nothing has yet reached the side or end walls. So the blobs are only the antenna. They are located where Harminv calculates the best resonance from the antenna/cavity combination, but that is a different run, different image.
@aero, Shell and Rodal: To clarify my mind, here is attached what I mean by putting a loop antenna near the big end "in the middle of thenodelobe". My concern is how could we reconcile such a large loop with the fact its perimeter should be equal to λ/4 to trigger resonance in the cavity (with lambda being between 12 and 15 cm)?
@X_Ray, this is a simplified sketch of a loop antenna, for didactic popularization purpose ;) The important thing to consider is the location of the loop WRT the cavity walls, end plates and mode shape. For example the two horizontal rods could be build in such a way they would not electromagnetically interfere with the waves, unlike in the sketch.
NSF-1701 update - Test complete! Myself and the whole assembly came through without a scratch. I started this project with the commitment to report on exactly what I measured. What I measured was no apparent movement of the fulcrum in response to the magnetron being powered on. However, my ability to measure below about 20 mg of gram-force is just not there.Congrats on an heroic experimental attempt!
Therefore, in the configuration of the frustum with power insertion from the small base, 3.5 cm from the side wall; the result is Null to the best of my knowledge.
The video is still uploading and will be for some time. I'll post a link when it becomes available. Those of you who may want to download it and zoom in tightly on the laser target for further analysis are welcomed to do so. Power on is easily noted by transformer hum.
NSF-1701 update - Test complete! Myself and the whole assembly came through without a scratch. I started this project with the commitment to report on exactly what I measured. What I measured was no apparent movement of the fulcrum in response to the magnetron being powered on. However, my ability to measure below about 20 mg of gram-force is just not there.
Therefore, in the configuration of the frustum with power insertion from the small base, 3.5 cm from the side wall; the result is Null to the best of my knowledge.
The video is still uploading and will be for some time. I'll post a link when it becomes available. Those of you who may want to download it and zoom in tightly on the laser target for further analysis are welcomed to do so. Power on is easily noted by transformer hum.
Yes, I'd like to. Seems to be a lot of hand-wringing about the antenna placement. Perhaps I'll let that settle before I remount the magnetron. Its not all that difficult except side mounting does tear into the mesh. Once thing for sure, top insertion on the small base in probably off the radar for future builds.NSF-1701 update - Test complete! Myself and the whole assembly came through without a scratch. I started this project with the commitment to report on exactly what I measured. What I measured was no apparent movement of the fulcrum in response to the magnetron being powered on. However, my ability to measure below about 20 mg of gram-force is just not there.Congrats on an heroic experimental attempt!
Therefore, in the configuration of the frustum with power insertion from the small base, 3.5 cm from the side wall; the result is Null to the best of my knowledge.
The video is still uploading and will be for some time. I'll post a link when it becomes available. Those of you who may want to download it and zoom in tightly on the laser target for further analysis are welcomed to do so. Power on is easily noted by transformer hum.
Do you plan to vary any parameters and retest?
Congrats on the test. More useful data, the screen apparently does minimize thermal ballooning effect.
Yes, I'd like to. Seems to be a lot of hand-wringing about the antenna placement. Perhaps I'll let that settle before I remount the magnetron. Its not all that difficult except side mounting does tear into the mesh. Once thing for sure, top insertion on the small base in probably off the radar for future builds.NSF-1701 update - Test complete! Myself and the whole assembly came through without a scratch. I started this project with the commitment to report on exactly what I measured. What I measured was no apparent movement of the fulcrum in response to the magnetron being powered on. However, my ability to measure below about 20 mg of gram-force is just not there.Congrats on an heroic experimental attempt!
Therefore, in the configuration of the frustum with power insertion from the small base, 3.5 cm from the side wall; the result is Null to the best of my knowledge.
The video is still uploading and will be for some time. I'll post a link when it becomes available. Those of you who may want to download it and zoom in tightly on the laser target for further analysis are welcomed to do so. Power on is easily noted by transformer hum.
Do you plan to vary any parameters and retest?
Flux capacitor,
One can visualize the cavity as a parallel resonant RLC circuit. One also seeks to not perturb it so as to cause modeing and other undesirable effects. That means you minimize the necessary coupling to that what is needed to efficiently transfer energy but not load the circuit down which will lower the Q, lower the resonance freq. Think as the coupling loop as an inductance paralleling the RLC of the cavity, so you want to minimize it. As Shell has pointed out, there is a multitude of ways to excite this cavity, I would pick the easiest one, the loop which can be rotated to vary the coupling, the probe length can be lowered to minimize coupling.
To excite TE01 you need to excite a magnetic field in the longitudinal direction of the axis of axi-symmetry. If you want to keep the loop perimeter λ/4, what prevents one from making a loop λ/4 perimeter and placing it so that its center goes through the axis of axi-symmetry?
Yes, that's what CERN recommends in prior papers I posted.To excite TE01 you need to excite a magnetic field in the longitudinal direction of the axis of axi-symmetry. If you want to keep the loop perimeter λ/4, what prevents one from making a loop λ/4 perimeter and placing it so that its center goes through the axis of axi-symmetry?
This?
Congrats on the test. More useful data, the screen apparently does minimize thermal ballooning effect.
And the wire mesh prevents the accumulation of hot gas inside the frustum. Buoyancy is an enemy to defeat in this kind of tests.
Yes, that's what CERN recommends in prior papers I posted.To excite TE01 you need to excite a magnetic field in the longitudinal direction of the axis of axi-symmetry. If you want to keep the loop perimeter λ/4, what prevents one from making a loop λ/4 perimeter and placing it so that its center goes through the axis of axi-symmetry?
This?
The purpose of the loop is to excite a magnetic field.
The magnetic field is in the longitudinal direction. The transverse field in the azimuthal direction is electric, not magnetic
Hence you want the loop to have the magnetic field going through its center, not the electric field.
CONGRATULATIONS ON AN EXCELLENT RESULT
I have NO doubt about a recommendation:
place the magnetron at the big base
1) This is consistent with my prior recommendation based on Meep/Wolfram-Mathematica runs
2) You will not need to tear into the side mesh
3) It would be inconsistent to feed from the side at this point in time. First you need to place the magnetron at the opposite side: at the big base to compare with running the magnetron at the small base in this run.
4) If you can place the magnetron at the center of the big base, that would be best.
Anybody that wants you to tear up the sides and mount on the side should wait until the next logical test takes place: magnetron at the big base.
....
Ok then. I may be mistaken because I'm representing in my head the loop antenna as a flat solenoid. A solenoid there would trigger an axial magnetic field as you say, but would tighten the magnetic lobes towards the axis of axi-symmetry because of the return path of the magnetic field lines around the coil. An antenna may behave differently.
...
And as X_Ray and cee said, a cavity resonates in certain mode shapes due to its dimensions, which should help stabilize the desired mode.
NSF-1701 update - Test complete! Myself and the whole assembly came through without a scratch. I started this project with the commitment to report on exactly what I measured. What I measured was no apparent movement of the fulcrum in response to the magnetron being powered on. However, my ability to measure below about 20 mg of gram-force is just not there.
Therefore, in the configuration of the frustum with power insertion from the small base, 3.5 cm from the side wall; the result is Null to the best of my knowledge.
The video is still uploading and will be for some time. I'll post a link when it becomes available. Those of you who may want to download it and zoom in tightly on the laser target for further analysis are welcomed to do so. Power on is easily noted by transformer hum.
NSF-1701 update - Test complete! Myself and the whole assembly came through without a scratch. I started this project with the commitment to report on exactly what I measured. What I measured was no apparent movement of the fulcrum in response to the magnetron being powered on. However, my ability to measure below about 20 mg of gram-force is just not there.
Therefore, in the configuration of the frustum with power insertion from the small base, 3.5 cm from the side wall; the result is Null to the best of my knowledge.
The video is still uploading and will be for some time. I'll post a link when it becomes available. Those of you who may want to download it and zoom in tightly on the laser target for further analysis are welcomed to do so. Power on is easily noted by transformer hum.
....
Ok then. I may be mistaken because I'm representing in my head the loop antenna as a flat solenoid. A solenoid there would trigger an axial magnetic field as you say, but would tighten the magnetic lobes towards the axis of axi-symmetry because of the return path of the magnetic field lines around the coil. An antenna may behave differently.
...
And as X_Ray and cee said, a cavity resonates in certain mode shapes due to its dimensions, which should help stabilize the desired mode.
Your picture shows magnetic lobes that vary in the azimuthal direction.
What magnetic toroidal lobes in TE012 ????:
The magnetic vector component in the azimuthal direction is zero for TE012.
The magnetic vector component in the polar angle theta direction is constant in the azimuthal direction for TE012, it varies in the theta and longitudinal direction. It does NOT vary in the azimuthal direction. No magnetic toroidal variation in the azimuthal direction.
Here's the video of the flight test:
Definitely not Hollywood...take it easy on me ;)
Here's the video of the flight test:
Definitely not Hollywood...take it easy on me ;)
https://www.youtube.com/watch?v=FPBs6zDmhwU
NSF-1701 update - Test complete! Myself and the whole assembly came through without a scratch. I started this project with the commitment to report on exactly what I measured. What I measured was no apparent movement of the fulcrum in response to the magnetron being powered on. However, my ability to measure below about 20 mg of gram-force is just not there.
Therefore, in the configuration of the frustum with power insertion from the small base, 3.5 cm from the side wall; the result is Null to the best of my knowledge.
The video is still uploading and will be for some time. I'll post a link when it becomes available. Those of you who may want to download it and zoom in tightly on the laser target for further analysis are welcomed to do so. Power on is easily noted by transformer hum.
....
Ok then. I may be mistaken because I'm representing in my head the loop antenna as a flat solenoid. A solenoid there would trigger an axial magnetic field as you say, but would tighten the magnetic lobes towards the axis of axi-symmetry because of the return path of the magnetic field lines around the coil. An antenna may behave differently.
...
And as X_Ray and cee said, a cavity resonates in certain mode shapes due to its dimensions, which should help stabilize the desired mode.
Your picture shows magnetic lobes that vary in the azimuthal direction.
What magnetic toroidal lobes in TE012 ????:
The magnetic vector component in the azimuthal direction is zero for TE012.
The magnetic vector component in the polar angle theta direction is constant in the azimuthal direction for TE012, it varies in the theta and longitudinal direction. It does NOT vary in the azimuthal direction. No magnetic toroidal variation in the azimuthal direction.
It is my understanding that the blue lines in Eagleworks pictures I've posted are magnetic field lines. Eagleworks even draw vectors on the right of the drawing, showing the magnetic field is swirling from one direction along the axis of axi-symmetry (where the magnetic field is the strongest) with looping return paths near the walls of the cavity in the other direction (where the magnetic field is weaker). Directions are inverted for the lobes near the other end. Are we talking about the same thing?
The picture below is from Eagleworks. I added the captions about magnetic fields.
EDIT: Good Lord, when I wrote "toroidal" I really wanted to write poloidal field lines (around a torus shape) and not toroidal field lines (in the azimuthal direction, there is no magnetic field in that direction of course) :-X
I edited the drawing in my prior post (http://forum.nasaspaceflight.com/index.php?topic=38203.msg1419630#msg1419630).
To excite TE01 you need to excite a magnetic field in the longitudinal direction of the axis of axi-symmetry. If you want to keep the loop perimeter λ/4, what prevents one from making a loop λ/4 perimeter and placing it so that its center goes through the axis of axi-symmetry?
This?
Here's the video of the flight test:First, congrats on the experimentation. But I'm a bit confused:
Definitely not Hollywood...take it easy on me ;)
https://www.youtube.com/watch?v=FPBs6zDmhwU
NSF-1701 update - Test complete! Myself and the whole assembly came through without a scratch. I started this project with the commitment to report on exactly what I measured. What I measured was no apparent movement of the fulcrum in response to the magnetron being powered on. However, my ability to measure below about 20 mg of gram-force is just not there.
Therefore, in the configuration of the frustum with power insertion from the small base, 3.5 cm from the side wall; the result is Null to the best of my knowledge.
The video is still uploading and will be for some time. I'll post a link when it becomes available. Those of you who may want to download it and zoom in tightly on the laser target for further analysis are welcomed to do so. Power on is easily noted by transformer hum.
Um, looks like the force (if any) was toward the large base (i.e up). Somebody with some batter software than snipit and GIMP want to do a better screen capture and put some lines on this thing?
For comparison, could someone do the same with the before, during and after positions of the laser light when he added the 200mg (I think) calibration weight to the frustrum before he ran his test?Um, looks like the force (if any) was toward the large base (i.e up). Somebody with some batter software than snipit and GIMP want to do a better screen capture and put some lines on this thing?
For comparison, could someone do the same with the before, during and after positions of the laser light when he added the 200mg (I think) calibration weight to the frustrum before he ran his test?Um, looks like the force (if any) was toward the large base (i.e up). Somebody with some batter software than snipit and GIMP want to do a better screen capture and put some lines on this thing?
Um, looks like the force (if any) was toward the large base (i.e up). Somebody with some batter software than snipit and GIMP want to do a better screen capture and put some lines on this thing?
Enhance.... enhance more, zoom, increase contrast. It is definitely positional change.
Out to the shop again....
Um, looks like the force (if any) was toward the large base (i.e up). Somebody with some batter software than snipit and GIMP want to do a better screen capture and put some lines on this thing?
Enhance.... enhance more, zoom, increase contrast. It is definitely positional change.
Out to the shop again....
Those frames are at 2:50, 3:35, and 10:49. Positional changes like that are expected with rfmwguy moving around the lab.
Frame grabs need to be done as the power cycles during a test run. The first run with the 30% power cycle over five minutes would be best, since the rig needs time to settle when rfmwguy starts it and leaves the room. Wait until the first minute into the run and then grab frames. You can hear the power cycle on and off.
Staring at the screen I didn't notice any movement.
Um, looks like the force (if any) was toward the large base (i.e up). Somebody with some batter software than snipit and GIMP want to do a better screen capture and put some lines on this thing?
Enhance.... enhance more, zoom, increase contrast. It is definitely positional change.
Out to the shop again....
Those frames are at 2:50, 3:35, and 10:49. Positional changes like that are expected with rfmwguy moving around the lab.
Frame grabs need to be done as the power cycles during a test run. The first run with the 30% power cycle over five minutes would be best, since the rig needs time to settle when rfmwguy starts it and leaves the room. Wait until the first minute into the run and then grab frames. You can hear the power cycle on and off.
Staring at the screen I didn't notice any movement.
I found before to be anytime before 3:00. During the test I see around 3:24 (or you 3:35 is fine) but I would take the "after" as being around 4:00 - NOT the 10:49, which is after all the tests. Okay, maybe include that, too.
My goal is to see the deflection due strictly to the calibration test - before adding the weight, while the weight is added, and after removing the weight. The final position should be the same as the beginning position of the powered runs.
...
EDIT: Good Lord, when I wrote "toroidal" I really wanted to write poloidal field lines (around a torus shape) and not toroidal field lines (in the azimuthal direction, there is no magnetic field in that direction of course) :-X
I edited the drawing in my prior post (http://forum.nasaspaceflight.com/index.php?topic=38203.msg1419630#msg1419630).
Thanks peter, yes I got the pm but was too busy setting up the flight test. Good comments. Yes galinstan is heavier than I would like an believe it dampens small movements and surface tension is an undesireable effect. Wish I had some other liquid to conduct the supply voltages.NSF-1701 update - Test complete! Myself and the whole assembly came through without a scratch. I started this project with the commitment to report on exactly what I measured. What I measured was no apparent movement of the fulcrum in response to the magnetron being powered on. However, my ability to measure below about 20 mg of gram-force is just not there.
Therefore, in the configuration of the frustum with power insertion from the small base, 3.5 cm from the side wall; the result is Null to the best of my knowledge.
The video is still uploading and will be for some time. I'll post a link when it becomes available. Those of you who may want to download it and zoom in tightly on the laser target for further analysis are welcomed to do so. Power on is easily noted by transformer hum.
Congratulations on your efforts.
Did you get my PM?
As I said, the thing is that the galinstan is a heavy alloy, 6 times heavier than water, so you need a bit more thrust to overcome the buoyancy force. Those 3 wires are quite thick so to avoid oscillating or the frustum standing still, you need a several dozen milinewtons more. In addition the emdrive is ballooning.
So my recommendation is to place the magnetron close to the big end or at the center of it in order to get more unbalanced force and/or turn the cavity upside down.
Best of luck.
Peter.
Um, looks like the force (if any) was toward the large base (i.e up). Somebody with some batter software than snipit and GIMP want to do a better screen capture and put some lines on this thing?
Enhance.... enhance more, zoom, increase contrast. It is definitely positional change.
Out to the shop again....
Those frames are at 2:50, 3:35, and 10:49. Positional changes like that are expected with rfmwguy moving around the lab.
Frame grabs need to be done as the power cycles during a test run. The first run with the 30% power cycle over five minutes would be best, since the rig needs time to settle when rfmwguy starts it and leaves the room. Wait until the first minute into the run and then grab frames. You can hear the power cycle on and off.
Staring at the screen I didn't notice any movement.
When I designed NSF-1701, I built it to be reconfigurable.
So I did just that...Doc, here's the new setup with the magnetron centered on the big base as you recommended. Its all ready for a second flight test!
But, its been a big day and I need a break form the shop. I'll test it again in a couple of days.
A heartfelt thanks for all the support!
Thanks peter, yes I got the pm but was too busy setting up the flight test. Good comments. Yes galinstan is heavier than I would like an believe it dampens small movements and surface tension is an undesireable effect. Wish I had some other liquid to conduct the supply voltages.Of course, it's current-carrying capability that's at stake here. I don't think these are too severe - maybe 10 Amps for the heater?
Thanks peter, yes I got the pm but was too busy setting up the flight test. Good comments. Yes galinstan is heavier than I would like an believe it dampens small movements and surface tension is an undesireable effect. Wish I had some other liquid to conduct the supply voltages.NSF-1701 update - Test complete! Myself and the whole assembly came through without a scratch. I started this project with the commitment to report on exactly what I measured. What I measured was no apparent movement of the fulcrum in response to the magnetron being powered on. However, my ability to measure below about 20 mg of gram-force is just not there.
Therefore, in the configuration of the frustum with power insertion from the small base, 3.5 cm from the side wall; the result is Null to the best of my knowledge.
The video is still uploading and will be for some time. I'll post a link when it becomes available. Those of you who may want to download it and zoom in tightly on the laser target for further analysis are welcomed to do so. Power on is easily noted by transformer hum.
Congratulations on your efforts.
Did you get my PM?
As I said, the thing is that the galinstan is a heavy alloy, 6 times heavier than water, so you need a bit more thrust to overcome the buoyancy force. Those 3 wires are quite thick so to avoid oscillating or the frustum standing still, you need a several dozen milinewtons more. In addition the emdrive is ballooning.
So my recommendation is to place the magnetron close to the big end or at the center of it in order to get more unbalanced force and/or turn the cavity upside down.
Best of luck.
Peter.
How do you know whether or not the power was on or off at those times and how are you ignoring the screen grabs with time stamps of what other people have posted?Um, looks like the force (if any) was toward the large base (i.e up). Somebody with some batter software than snipit and GIMP want to do a better screen capture and put some lines on this thing?
Enhance.... enhance more, zoom, increase contrast. It is definitely positional change.
Out to the shop again....
Those frames are at 2:50, 3:35, and 10:49. Positional changes like that are expected with rfmwguy moving around the lab.
Frame grabs need to be done as the power cycles during a test run. The first run with the 30% power cycle over five minutes would be best, since the rig needs time to settle when rfmwguy starts it and leaves the room. Wait until the first minute into the run and then grab frames. You can hear the power cycle on and off.
Staring at the screen I didn't notice any movement.
I grabbed three frames during the five minute run when the power was off (5:25, 6:00, and 6:25) and three frames when the power was on (5:45, 6:10, and 6:35). Then I selected a point in the pattern to measure the pixel location. I looked at each frame at 500% so I could easily see the pixels. Each one is at the same location within +/- 1 pixel. There isn't any appreciable movement at the level of resolution of this experiment.
It is a null result.
The stability of rfmwguy's setup is impressive. This is good clean data that sets an upper limit to any thrust made by NSF-1701. Of course, the antenna location may not be optimal, but Dr. Rodal's suggested follow on test will see if the meep analysis helps.
It is a null result.
The stability of rfmwguy's setup is impressive. This is good clean data that sets an upper limit to any thrust made by NSF-1701. Of course, the antenna location may not be optimal, but Dr. Rodal's suggested follow on test will see if the meep analysis helps.
When I designed NSF-1701, I built it to be reconfigurable.
So I did just that...Doc, here's the new setup with the magnetron centered on the big base as you recommended. Its all ready for a second flight test!
But, its been a big day and I need a break form the shop. I'll test it again in a couple of days.
A heartfelt thanks for all the support!
When I designed NSF-1701, I built it to be reconfigurable.
So I did just that...Doc, here's the new setup with the magnetron centered on the big base as you recommended. Its all ready for a second flight test!
But, its been a big day and I need a break form the shop. I'll test it again in a couple of days.
A heartfelt thanks for all the support!
That's a very nicely built apparatus. I'm not surprised at the results given you have virtually eliminated any bouyancy effects. One suggestion for everyone: Since this em-drive business is so far from the mainstream of accepted scientific theory and getting even further every day why not use a more off-beat measurement system? Instead of mgram-F = 9.8 uN why not use dynes, the CGS unit of force? 1 mGram-F = 1 dyne.
NSF-1701 update - Test complete! Myself and the whole assembly came through without a scratch. I started this project with the commitment to report on exactly what I measured. What I measured was no apparent movement of the fulcrum in response to the magnetron being powered on. However, my ability to measure below about 20 mg of gram-force is just not there.
Therefore, in the configuration of the frustum with power insertion from the small base, 3.5 cm from the side wall; the result is Null to the best of my knowledge.
The video is still uploading and will be for some time. I'll post a link when it becomes available. Those of you who may want to download it and zoom in tightly on the laser target for further analysis are welcomed to do so. Power on is easily noted by transformer hum.
Congratulations on your efforts.
Did you get my PM?
As I said, the thing is that the galinstan is a heavy alloy, 6 times heavier than water, so you need a bit more thrust to overcome the buoyancy force. Those 3 wires are quite thick so to avoid oscillating or the frustum standing still, you need a several dozen milinewtons more. In addition the emdrive is ballooning.
So my recommendation is to place the magnetron close to the big end or at the center of it in order to get more unbalanced force and/or turn the cavity upside down.
Best of luck.
Peter.
How do you know whether or not the power was on or off at those times and how are you ignoring the screen grabs with time stamps of what other people have posted?Um, looks like the force (if any) was toward the large base (i.e up). Somebody with some batter software than snipit and GIMP want to do a better screen capture and put some lines on this thing?
Enhance.... enhance more, zoom, increase contrast. It is definitely positional change.
Out to the shop again....
Those frames are at 2:50, 3:35, and 10:49. Positional changes like that are expected with rfmwguy moving around the lab.
Frame grabs need to be done as the power cycles during a test run. The first run with the 30% power cycle over five minutes would be best, since the rig needs time to settle when rfmwguy starts it and leaves the room. Wait until the first minute into the run and then grab frames. You can hear the power cycle on and off.
Staring at the screen I didn't notice any movement.
I grabbed three frames during the five minute run when the power was off (5:25, 6:00, and 6:25) and three frames when the power was on (5:45, 6:10, and 6:35). Then I selected a point in the pattern to measure the pixel location. I looked at each frame at 500% so I could easily see the pixels. Each one is at the same location within +/- 1 pixel. There isn't any appreciable movement at the level of resolution of this experiment.
It is a null result.
The stability of rfmwguy's setup is impressive. This is good clean data that sets an upper limit to any thrust made by NSF-1701. Of course, the antenna location may not be optimal, but Dr. Rodal's suggested follow on test will see if the meep analysis helps.
I am totally with deltaMass! This is excellent work guys!! My God this forum is amazing!!! :D
One thing that makes me wonder is why the fustrum never returns to its original position. Croppa's excellent montage shows this best in post 1130. It looks like something shifted or there is some type of ballooning effect (from what is not clear to me). Alternatively, we really are creating little warp drives! ;D
rmfguy- I am not sure how to put this but we may need the magnetron back at the top after all!!! :)
And additionally, the magnetron was still hot. Another thing is that the inertia of such a long balance scale is high, so no quick reaction.I am totally with deltaMass! This is excellent work guys!! My God this forum is amazing!!! :D
One thing that makes me wonder is why the fustrum never returns to its original position. Croppa's excellent montage shows this best in post 1130. It looks like something shifted or there is some type of ballooning effect (from what is not clear to me). Alternatively, we really are creating little warp drives! ;D
rmfguy- I am not sure how to put this but we may need the magnetron back at the top after all!!! :)
Probably because this is the way a knife edge fulcrum behaves. It sticks. It would be better to use ball bearings I think.
Todd
And additionally, the magnetron was still hot. Another thing is that the inertia of such a long balance scale is high, so no quick reaction.I am totally with deltaMass! This is excellent work guys!! My God this forum is amazing!!! :D
One thing that makes me wonder is why the fustrum never returns to its original position. Croppa's excellent montage shows this best in post 1130. It looks like something shifted or there is some type of ballooning effect (from what is not clear to me). Alternatively, we really are creating little warp drives! ;D
rmfguy- I am not sure how to put this but we may need the magnetron back at the top after all!!! :)
Probably because this is the way a knife edge fulcrum behaves. It sticks. It would be better to use ball bearings I think.
Todd
When I designed NSF-1701, I built it to be reconfigurable.
So I did just that...Doc, here's the new setup with the magnetron centered on the big base as you recommended. Its all ready for a second flight test!
But, its been a big day and I need a break form the shop. I'll test it again in a couple of days.
A heartfelt thanks for all the support!
And additionally, the magnetron was still hot. Another thing is that the inertia of such a long balance scale is high, so no quick reaction.I am totally with deltaMass! This is excellent work guys!! My God this forum is amazing!!! :D
One thing that makes me wonder is why the fustrum never returns to its original position. Croppa's excellent montage shows this best in post 1130. It looks like something shifted or there is some type of ballooning effect (from what is not clear to me). Alternatively, we really are creating little warp drives! ;D
rmfguy- I am not sure how to put this but we may need the magnetron back at the top after all!!! :)
Probably because this is the way a knife edge fulcrum behaves. It sticks. It would be better to use ball bearings I think.
Todd
Yes. Also, the actual thrust was very low and so the beam only moved fractionally. This means that the force available to move the beam back is also small, particularly compared to the mass of the beam.
Here is a better version of the montage. It's made from 1 pixel wide slices fixed on the laser spot. Each slice represents 0.25 seconds of the movie. They're stretched 8 times vertically and autocontrasted individually so the blue lines are where the image was dark (i.e rfmwguy in front of the laser).
I'll leave it to you guys to decide what's causing those "steps" during the 5 minute run... ;) :-\
Great work rfmwguy!This is about as cool as it gets! Well done...the downward trend is puzzling, which means the device is lifting, but not in a way id expect with thermals. Have to think about that for a while...
Here is a montage of how the region of interest looks throughout the whole movie (stretched in Y to make things clearer).
I decided to add one more screenshot. The new order is as follows (left to right)Boom! Id say ur first post was a winner! Thanks!
01:41 - Before calibration Weight
03:40 - While calibration weight is in place
04:13 - After calibration weight has been removed
08:27 - During 5 minute 30% test, while the magnetron is OFF
09:00 - During a cycle of the magnetron at the end of the 30% test
10:59 - During the 100% test
Huge congratulations rfmwguy! My practical skills are beyond weak, I can only stand in awe!Good thoughts here, I was quick to say null and learned that it takes time to properly analyze data. NSF folks are schooling me on this fact...I'm really impressed.
Two points though: if you had announced very positive results, sceptics would be demanding that you turned the apparatus upside down to eliminate buoyancy effects. However, a (nearly) null result could just as easily come from thrust down and buoyancy up. I would join the other commenter suggesting that you repeat the test upside-down, same with any future tests, and indeed for any future replicators.
Second, am I right this is the first test with a mesh frustrum? In determining that it is safe to move from a copper can to a mesh 'can', we are making assumptions about how the thing works which may not be valid (because we don't know how it works). Mesh might not be the way to go...
Your calibration was 200mg, 2x10^-4 kg, so circa 2mN. If the crowd-sourced analysis is right, the deflection seen is a modest multiple of that in the opposite direction. That is still several orders of magnitude more force/watt than a photon rocket, if it is a true reflection of the thrust produced.
Once again, fantastic work, keep going!
R.
@rfmwguy:
How do you reseal the hole left behind when you relocate the magnetron?
@rfmwguy:Good question. I replaced the entire top plate with a new board. No holes. I also replace the screen with a solid board, so only thing mesh now is frustum sides.
How do you reseal the hole left behind when you relocate the magnetron?
Yes, I watched that corny TV commercial for Flex Seal and thought it was the perfect solution ;)@rfmwguy:
How do you reseal the hole left behind when you relocate the magnetron?
With a magnetron hole resealer?
The magnetron should generate quite a bit of heat and the scale could dilate asymmetrically, this could be mistaken for thrust. Has this possible issue been considered?Yes, it was in my list of 6 different thermal effects.
...
EDIT: Good Lord, when I wrote "toroidal" I really wanted to write poloidal field lines (around a torus shape) and not toroidal field lines (in the azimuthal direction, there is no magnetic field in that direction of course) :-X
I edited the drawing in my prior post (http://forum.nasaspaceflight.com/index.php?topic=38203.msg1419630#msg1419630).
I knew what you meant. What @Rodal calls azimuthal, I refer to as "circular", when the flux lines are circling the minor diameter, I call it "toroidal" like you did. The word "poloidal" was not in my vocabulary. :(
Thanks!
Todd
Just a newbie but been following these threads closely - my thought on the movement 'up' towards the large end which wasnt expected - potentially still thermal effects? The magnetron heats the air in the frustum, it vents through the mesh and is trapped like a hot air balloon under the solid top plate and flange.Have put magnetron on top side and will look for similar effects in Flight Test #2 soon.
No idea if that volume of air could create that much force, but as long as there is area outside (or even inside?) the frustum on the top plate, it could be solved with a few holes to vent?
Just a newbie but been following these threads closely - my thought on the movement 'up' towards the large end which wasnt expected - potentially still thermal effects? The magnetron heats the air in the frustum, it vents through the mesh and is trapped like a hot air balloon under the solid top plate and flange.Have put magnetron on top side and will look for similar effects in Flight Test #2 soon.
No idea if that volume of air could create that much force, but as long as there is area outside (or even inside?) the frustum on the top plate, it could be solved with a few holes to vent?
Found it interesting that if it were thermal, it didn't start sooner...only the last 1/3 or so of test. Mag should have been up to temperature within the first min or so of tests.
It my guess for its thermal, but more data is coming...
Just a newbie but been following these threads closely - my thought on the movement 'up' towards the large end which wasnt expected - potentially still thermal effects? The magnetron heats the air in the frustum, it vents through the mesh and is trapped like a hot air balloon under the solid top plate and flange.Have put magnetron on top side and will look for similar effects in Flight Test #2 soon.
No idea if that volume of air could create that much force, but as long as there is area outside (or even inside?) the frustum on the top plate, it could be solved with a few holes to vent?
Found it interesting that if it were thermal, it didn't start sooner...only the last 1/3 or so of test. Mag should have been up to temperature within the first min or so of tests.
It my guess for its thermal, but more data is coming...
Wish I could. Without connectors, can't take it to my VNA pals just yet. If positive results from test #2, might slap an N connector with monopole on it. While its only going to give me return loss peaks, guess we could do the -3dB BW points like others have done (shudder).Just a newbie but been following these threads closely - my thought on the movement 'up' towards the large end which wasnt expected - potentially still thermal effects? The magnetron heats the air in the frustum, it vents through the mesh and is trapped like a hot air balloon under the solid top plate and flange.Have put magnetron on top side and will look for similar effects in Flight Test #2 soon.
No idea if that volume of air could create that much force, but as long as there is area outside (or even inside?) the frustum on the top plate, it could be solved with a few holes to vent?
Found it interesting that if it were thermal, it didn't start sooner...only the last 1/3 or so of test. Mag should have been up to temperature within the first min or so of tests.
It my guess for its thermal, but more data is coming...
Is there any way for you to guesstimate whether your cavity was resonating during the experiment with the magnetron on ?
Whether the Q was ~ 0 , ~1,000 or ~10,000 ?
Wish I could. Without connectors, can't take it to my VNA pals just yet. If positive results from test #2, might slap an N connector with monopole on it. While its only going to give me return loss peaks, guess we could do the -3dB BW points like others have done (shudder).Just a newbie but been following these threads closely - my thought on the movement 'up' towards the large end which wasnt expected - potentially still thermal effects? The magnetron heats the air in the frustum, it vents through the mesh and is trapped like a hot air balloon under the solid top plate and flange.Have put magnetron on top side and will look for similar effects in Flight Test #2 soon.
No idea if that volume of air could create that much force, but as long as there is area outside (or even inside?) the frustum on the top plate, it could be solved with a few holes to vent?
Found it interesting that if it were thermal, it didn't start sooner...only the last 1/3 or so of test. Mag should have been up to temperature within the first min or so of tests.
It my guess for its thermal, but more data is coming...
Is there any way for you to guesstimate whether your cavity was resonating during the experiment with the magnetron on ?
Whether the Q was ~ 0 , ~1,000 or ~10,000 ?
When I designed NSF-1701, I built it to be reconfigurable.
So I did just that...Doc, here's the new setup with the magnetron centered on the big base as you recommended. Its all ready for a second flight test!
But, its been a big day and I need a break form the shop. I'll test it again in a couple of days.
A heartfelt thanks for all the support!
I simple optical trick that may improve the sharpness of the laser dot in the movie is to move the camera back as far as possible and then to use the zoom (I hope your camera has one). This will make the paper with the laser dot sharper when you focus on the rig.
Wish I could. Without connectors, can't take it to my VNA pals just yet. If positive results from test #2, might slap an N connector with monopole on it. While its only going to give me return loss peaks, guess we could do the -3dB BW points like others have done (shudder).
No theory supports any particular resonance on return loss for a broad spectral signal source. The shape was based on your spreadsheet and nasa data, so I hardly say its flying blind.Wish I could. Without connectors, can't take it to my VNA pals just yet. If positive results from test #2, might slap an N connector with monopole on it. While its only going to give me return loss peaks, guess we could do the -3dB BW points like others have done (shudder).
Well that will at least give you a picture of the return loss resonant dip frequencies and the approx bandwidth / Q. At least then you are not flying blind and pumping Rf energy into a frustum you have no hard S11 data on.
Go on, be devil. Do it. Please record the S11 data scans and share. I suspect you may get a surprise.
No theory supports any particular resonance on return loss for a broad spectral signal source. The shape was based on your spreadsheet and nasa data, so I hardly say its flying blind.Wish I could. Without connectors, can't take it to my VNA pals just yet. If positive results from test #2, might slap an N connector with monopole on it. While its only going to give me return loss peaks, guess we could do the -3dB BW points like others have done (shudder).
Well that will at least give you a picture of the return loss resonant dip frequencies and the approx bandwidth / Q. At least then you are not flying blind and pumping Rf energy into a frustum you have no hard S11 data on.
Go on, be devil. Do it. Please record the S11 data scans and share. I suspect you may get a surprise.
I am just not convinced Q is part of the equation for force generation; at least I've not seen that. It is an arbitrary measure of frequency and amplitude performance. Useful only in my mind for source matching.
Let me know if you discover a force formula listing Q.
...
EDIT: Good Lord, when I wrote "toroidal" I really wanted to write poloidal field lines (around a torus shape) and not toroidal field lines (in the azimuthal direction, there is no magnetic field in that direction of course) :-X
I edited the drawing in my prior post (http://forum.nasaspaceflight.com/index.php?topic=38203.msg1419630#msg1419630).
I knew what you meant. What @Rodal calls azimuthal, I refer to as "circular", when the flux lines are circling the minor diameter, I call it "toroidal" like you did. The word "poloidal" was not in my vocabulary. :(
Thanks!
Todd
Sorry to get wonky, but let's discuss this further to agree on a common language to describe the complicated field distributons inside the truncated cone's EM Drive.
OK, to clarify this, I do agree that FluxCapacitor was correct that the word toroidal is a good description of the magnetic field as a solid, but with the magnetic field vectors oriented in the theta polar θ angle direction. The problem is that the word "torus" does not uniquely describe the direction of the magnetic vector field: the magnetic vector field is not in the azimuthal φ direction of the surface of the torus, but instead it is directed in the polar θ direction, of the cross section of the torus, in the plane {θ,r}, with normal φ
(http://mathworld.wolfram.com/images/eps-gif/StandardTori_701.gif)
There are no magnetic field vectors on the surface of the torus. The magnetic field vectors are in cross-sectional cuts of the torus.
The problem with using @WarpTech's proposed word "circular" is that in spherical polar coordinates (which are the intrinsic coordinates to describe the spherical waves inside the truncated cone) there are two circular directions in spherical coordinates, hence "circular" does not uniquely describe what circular direction one is talking about:
the azimuthal angle φ (phi)
the spherical polar angle, or "zenith angle" θ (theta)
(https://upload.wikimedia.org/wikipedia/commons/thumb/4/4f/3D_Spherical.svg/558px-3D_Spherical.svg.png)
(http://www.chemistryland.com/CHM151S/07-Atomic%20Structure/ElectronConfig/azimuth.gif)
https://en.wikipedia.org/wiki/Spherical_coordinate_system
"Circular" uniquely describes a direction for a cylinder, but not for a spherical cone, because "circular" does not uniquely identify what circular direction one is describing, since both φ and θ describe circles in different directions. Hence the word "circular" can lead to confusion as to what one is talking about.
(http://gregegan.customer.netspace.net.au/SCIENCE/Cavity/CavityShape.gif)
(http://mathworld.wolfram.com/images/eps-gif/SphericalCone_1000.gif)
CONCLUSION: It appears that the only unique way to describe these vector components is to identify the vector component directions: whether they are in:
the azimuthal angle φ (phi) direction
the spherical polar angle, or "zenith angle" θ (theta) direction
the spherical radial "r" direction
Yet, each measure Q differently...see my point?No theory supports any particular resonance on return loss for a broad spectral signal source. The shape was based on your spreadsheet and nasa data, so I hardly say its flying blind.Wish I could. Without connectors, can't take it to my VNA pals just yet. If positive results from test #2, might slap an N connector with monopole on it. While its only going to give me return loss peaks, guess we could do the -3dB BW points like others have done (shudder).
Well that will at least give you a picture of the return loss resonant dip frequencies and the approx bandwidth / Q. At least then you are not flying blind and pumping Rf energy into a frustum you have no hard S11 data on.
Go on, be devil. Do it. Please record the S11 data scans and share. I suspect you may get a surprise.
I am just not convinced Q is part of the equation for force generation; at least I've not seen that. It is an arbitrary measure of frequency and amplitude performance. Useful only in my mind for source matching.
Let me know if you discover a force formula listing Q.
I updated my post. Please review.
Both Shawyer and Prof Yangs Force equations involve Q.
@rfmwguy, it seems like many people are saying that the movement of the laser dot should be interpreted as a thrust signal and therefore the test should in fact be considered positive as opposed to null [1].Wolfy, one thing I learned is not to judge too quickly on results for such a small measurement. I had not gone to the great effort of clipping the laser out and putting it into a time line.
In your opinion, is the test result null or positive (or indeterminate)? Are you standing by your previous statement that the test result was null?
[1] - Ignoring the fact that the laser moves in the wrong direction and the beam displays an unusual dynamic, where deflection seems to grow at a constant rate over the course of power on.
RFMWGUY - great work, even better reporting :)Appreciate it, guess I could use the static laser firing on a moving mirror. Let me get back with you on that...after flight test #2. Did the pinhole trick, simply attenuated the output. Its a cheapo laser pointer with no focusing capability, but its super lightweight. Thanks for the mirror heads-up. I'd love to get one locally.
Two simple suggestions on the laser pointer that hopefully won't break the bank:
1) use a first-surface mirror, not one that's silvered on the back of the glass. Check with a local glass/mirror supply house, jewelry shops use them in displays sometimes so a small piece like you need may be cheap.
2) try the pin-hole card trick (I don't think you did this already?) which should clean up the spot itself.
Seems like what you really want for the liquid current transfer mechanism is mercury...
Edit: O $hit. I just remembered I have a 5mw HeNe laser - WAY better spot definition than what you have. But it would need 120v power... I will gladly loan this to the cause if there's any way it would be helpful.
I just ordered 2 under 8 bucks with shipping.RFMWGUY - great work, even better reporting :)Appreciate it, guess I could use the static laser firing on a moving mirror. Let me get back with you on that...after flight test #2. Did the pinhole trick, simply attenuated the output. Its a cheapo laser pointer with no focusing capability, but its super lightweight. Thanks for the mirror heads-up. I'd love to get one locally.
Two simple suggestions on the laser pointer that hopefully won't break the bank:
1) use a first-surface mirror, not one that's silvered on the back of the glass. Check with a local glass/mirror supply house, jewelry shops use them in displays sometimes so a small piece like you need may be cheap.
2) try the pin-hole card trick (I don't think you did this already?) which should clean up the spot itself.
Seems like what you really want for the liquid current transfer mechanism is mercury...
Edit: O $hit. I just remembered I have a 5mw HeNe laser - WAY better spot definition than what you have. But it would need 120v power... I will gladly loan this to the cause if there's any way it would be helpful.
I just ordered 2 under 8 bucks with shipping.RFMWGUY - great work, even better reporting :)Appreciate it, guess I could use the static laser firing on a moving mirror. Let me get back with you on that...after flight test #2. Did the pinhole trick, simply attenuated the output. Its a cheapo laser pointer with no focusing capability, but its super lightweight. Thanks for the mirror heads-up. I'd love to get one locally.
Two simple suggestions on the laser pointer that hopefully won't break the bank:
1) use a first-surface mirror, not one that's silvered on the back of the glass. Check with a local glass/mirror supply house, jewelry shops use them in displays sometimes so a small piece like you need may be cheap.
2) try the pin-hole card trick (I don't think you did this already?) which should clean up the spot itself.
Seems like what you really want for the liquid current transfer mechanism is mercury...
Edit: O $hit. I just remembered I have a 5mw HeNe laser - WAY better spot definition than what you have. But it would need 120v power... I will gladly loan this to the cause if there's any way it would be helpful.
American Science & Surplus
MIRROR, FIRST SURFACE/39MM X 97MM X 3MM THK
Item Number: 31016P1
Quantity: 2
Back to the shop...
Stiction is the static friction that needs to be overcome to enable relative motion of stationary objects in contact.[1] The term is a portmanteau of the term "static friction",[2] perhaps also influenced by the verb "stick".
Any solid objects pressing against each other (but not sliding) will require some threshold of force parallel to the surface of contact in order to overcome static cohesion. Stiction is a threshold, not a continuous force.
In situations where two surfaces with areas below the micrometer range come into close proximity (as in an accelerometer), they may adhere together. At this scale, electrostatic and/or Van der Waals and hydrogen bonding forces become significant. The phenomenon of two such surfaces being adhered together in this manner is also called stiction. Stiction may be related to hydrogen bonding or residual contamination.
from wikipedia -QuoteStiction is the static friction that needs to be overcome to enable relative motion of stationary objects in contact.[1] The term is a portmanteau of the term "static friction",[2] perhaps also influenced by the verb "stick".
Any solid objects pressing against each other (but not sliding) will require some threshold of force parallel to the surface of contact in order to overcome static cohesion. Stiction is a threshold, not a continuous force.
In situations where two surfaces with areas below the micrometer range come into close proximity (as in an accelerometer), they may adhere together. At this scale, electrostatic and/or Van der Waals and hydrogen bonding forces become significant. The phenomenon of two such surfaces being adhered together in this manner is also called stiction. Stiction may be related to hydrogen bonding or residual contamination.
@rfmwguy - You mentioned transformer vibration. I wonder if a vibrator attached near the knife edges would help reduce stiction without causing worse problems elsewhere? Or would it cause the weight to cut into the edges. And is there any indication of knife edge wear at the point of contact?
from wikipedia -Good news is before the test, I lifted and slightly moved the fulcrum to an unused part of the blades. Realize I can only do this so often, but really haven't seen any gouging. I did get the more expensive blades. Have 2 more unused!QuoteStiction is the static friction that needs to be overcome to enable relative motion of stationary objects in contact.[1] The term is a portmanteau of the term "static friction",[2] perhaps also influenced by the verb "stick".
Any solid objects pressing against each other (but not sliding) will require some threshold of force parallel to the surface of contact in order to overcome static cohesion. Stiction is a threshold, not a continuous force.
In situations where two surfaces with areas below the micrometer range come into close proximity (as in an accelerometer), they may adhere together. At this scale, electrostatic and/or Van der Waals and hydrogen bonding forces become significant. The phenomenon of two such surfaces being adhered together in this manner is also called stiction. Stiction may be related to hydrogen bonding or residual contamination.
@rfmwguy - You mentioned transformer vibration. I wonder if a vibrator attached near the knife edges would help reduce stiction without causing worse problems elsewhere? Or would it cause the weight to cut into the edges. And is there any indication of knife edge wear at the point of contact?
from wikipedia -Good news is before the test, I lifted and slightly moved the fulcrum to an unused part of the blades. Realize I can only do this so often, but really haven't seen any gouging. I did get the more expensive blades. Have 2 more unused!QuoteStiction is the static friction that needs to be overcome to enable relative motion of stationary objects in contact.[1] The term is a portmanteau of the term "static friction",[2] perhaps also influenced by the verb "stick".
Any solid objects pressing against each other (but not sliding) will require some threshold of force parallel to the surface of contact in order to overcome static cohesion. Stiction is a threshold, not a continuous force.
In situations where two surfaces with areas below the micrometer range come into close proximity (as in an accelerometer), they may adhere together. At this scale, electrostatic and/or Van der Waals and hydrogen bonding forces become significant. The phenomenon of two such surfaces being adhered together in this manner is also called stiction. Stiction may be related to hydrogen bonding or residual contamination.
@rfmwguy - You mentioned transformer vibration. I wonder if a vibrator attached near the knife edges would help reduce stiction without causing worse problems elsewhere? Or would it cause the weight to cut into the edges. And is there any indication of knife edge wear at the point of contact?
I have doubts about static/stiction since the contact surface is so small and the wood beam itself is not likely to store or transfer a static charge as a plastic or composite might. With more surface area in contact, a ball-bearing assembly might be more prone to this than a knife-edge, not sure.
Figure it out :) i mean try it.from wikipedia -Good news is before the test, I lifted and slightly moved the fulcrum to an unused part of the blades. Realize I can only do this so often, but really haven't seen any gouging. I did get the more expensive blades. Have 2 more unused!QuoteStiction is the static friction that needs to be overcome to enable relative motion of stationary objects in contact.[1] The term is a portmanteau of the term "static friction",[2] perhaps also influenced by the verb "stick".
Any solid objects pressing against each other (but not sliding) will require some threshold of force parallel to the surface of contact in order to overcome static cohesion. Stiction is a threshold, not a continuous force.
In situations where two surfaces with areas below the micrometer range come into close proximity (as in an accelerometer), they may adhere together. At this scale, electrostatic and/or Van der Waals and hydrogen bonding forces become significant. The phenomenon of two such surfaces being adhered together in this manner is also called stiction. Stiction may be related to hydrogen bonding or residual contamination.
@rfmwguy - You mentioned transformer vibration. I wonder if a vibrator attached near the knife edges would help reduce stiction without causing worse problems elsewhere? Or would it cause the weight to cut into the edges. And is there any indication of knife edge wear at the point of contact?
I have doubts about static/stiction since the contact surface is so small and the wood beam itself is not likely to store or transfer a static charge as a plastic or composite might. With more surface area in contact, a ball-bearing assembly might be more prone to this than a knife-edge, not sure.
Just some random thought after a nights reflection:
Because of the ease or configuration and seemingly positive test result, I think rmfguy's mesh setup just became one of the preferred research setups for future test.
I think the idea that nothing will happen with the feed near the small base is not looking good. Fortunately rmfguy's setup seems perfect for a series of tests comparing feeds at the small and large base as well as mesh and solid endplates.
I'm seeing multiple indications that force builds up relatively slowly over time. I'm afraid to say it, but I think we might need some meep runs showing what is going at least until projected force stops increasing with time (which might be several minutes in realtime). Can we get an estimate about how much computing power we're talking about here? Is this supercomputer range stuff? I've got a Linux box with ok specs (but in need of a bigger hard drive) that I could donate to the cause for a month. I suspect the computing requirements are somewhere far north of a desktop system.
If it weren't for inertia on the beam, I'd say these results indicate that the point of maximum efficiency differs from the point of maximum power.
I wonder if one of the laser rangerfinders used in golf (about $20) or hunting (about $150) would provide a better beam than the current laser pointer.
Speaking of mirrors, somebody mentions cannibalizing an old film SLR for a better mirror. I should add that a larger mirror might be available from one of the Pentax medium format SLRs.
Yes the choice of different coordinate systems can lead to miscommunication ::)...
EDIT: Good Lord, when I wrote "toroidal" I really wanted to write poloidal field lines (around a torus shape) and not toroidal field lines (in the azimuthal direction, there is no magnetic field in that direction of course) :-X
I edited the drawing in my prior post (http://forum.nasaspaceflight.com/index.php?topic=38203.msg1419630#msg1419630).
I knew what you meant. What @Rodal calls azimuthal, I refer to as "circular", when the flux lines are circling the minor diameter, I call it "toroidal" like you did. The word "poloidal" was not in my vocabulary. :(
Thanks!
Todd
Sorry to get wonky, but let's discuss this further to agree on a common language to describe the complicated field distributons inside the truncated cone's EM Drive.
OK, to clarify this, I do agree that FluxCapacitor was correct that the word toroidal is a good description of the magnetic field as a solid, but with the magnetic field vectors oriented in the theta polar θ angle direction. The problem is that the word "torus" does not uniquely describe the direction of the magnetic vector field: the magnetic vector field is not in the azimuthal φ direction of the surface of the torus, but instead it is directed in the polar θ direction, of the cross section of the torus, in the plane {θ,r}, with normal φ
(http://mathworld.wolfram.com/images/eps-gif/StandardTori_701.gif)
There are no magnetic field vectors on the surface of the torus. The magnetic field vectors are in cross-sectional cuts of the torus.
The problem with using @WarpTech's proposed word "circular" is that in spherical polar coordinates (which are the intrinsic coordinates to describe the spherical waves inside the truncated cone) there are two circular directions in spherical coordinates, hence "circular" does not uniquely describe what circular direction one is talking about:
the azimuthal angle φ (phi)
the spherical polar angle, or "zenith angle" θ (theta)
(https://upload.wikimedia.org/wikipedia/commons/thumb/4/4f/3D_Spherical.svg/558px-3D_Spherical.svg.png)
(http://www.chemistryland.com/CHM151S/07-Atomic%20Structure/ElectronConfig/azimuth.gif)
https://en.wikipedia.org/wiki/Spherical_coordinate_system
"Circular" uniquely describes a direction for a cylinder, but not for a spherical cone, because "circular" does not uniquely identify what circular direction one is describing, since both φ and θ describe circles in different directions. Hence the word "circular" can lead to confusion as to what one is talking about.
(http://gregegan.customer.netspace.net.au/SCIENCE/Cavity/CavityShape.gif)
(http://mathworld.wolfram.com/images/eps-gif/SphericalCone_1000.gif)
CONCLUSION: It appears that the only unique way to describe these vector components is to identify the vector component directions: whether they are in:
the azimuthal angle φ (phi) direction
the spherical polar angle, or "zenith angle" θ (theta) direction
the spherical radial "r" direction
The problem is not one of definition, it is vocabulary. It is obvious to me what you are saying, but in my vocabulary, the phi direction is around the major diameter and the theta direction is around the minor diameter. I have always referred to the theta direction as "toroidal". The phi direction is cylindrical or circular. It's just how I learned it.
Todd
Likely because I moved the camera immediately after end of last 1 minute full power test. I won't do that next time.from wikipedia -Good news is before the test, I lifted and slightly moved the fulcrum to an unused part of the blades. Realize I can only do this so often, but really haven't seen any gouging. I did get the more expensive blades. Have 2 more unused!QuoteStiction is the static friction that needs to be overcome to enable relative motion of stationary objects in contact.[1] The term is a portmanteau of the term "static friction",[2] perhaps also influenced by the verb "stick".
Any solid objects pressing against each other (but not sliding) will require some threshold of force parallel to the surface of contact in order to overcome static cohesion. Stiction is a threshold, not a continuous force.
In situations where two surfaces with areas below the micrometer range come into close proximity (as in an accelerometer), they may adhere together. At this scale, electrostatic and/or Van der Waals and hydrogen bonding forces become significant. The phenomenon of two such surfaces being adhered together in this manner is also called stiction. Stiction may be related to hydrogen bonding or residual contamination.
@rfmwguy - You mentioned transformer vibration. I wonder if a vibrator attached near the knife edges would help reduce stiction without causing worse problems elsewhere? Or would it cause the weight to cut into the edges. And is there any indication of knife edge wear at the point of contact?
I have doubts about static/stiction since the contact surface is so small and the wood beam itself is not likely to store or transfer a static charge as a plastic or composite might. With more surface area in contact, a ball-bearing assembly might be more prone to this than a knife-edge, not sure.
Rmfguy, what is your opinion as to why the beam did not return back?
http://arxiv.org/abs/quant-ph/0603073
About berry phases and forces.
Following the article, the slow classical part will be the cavity, the fast quantum part will be the electromagnetic fields modes in cavity.
The only Plank I see around here is rfmwguy's floobie-stick 8)http://arxiv.org/abs/quant-ph/0603073
About berry phases and forces.
Following the article, the slow classical part will be the cavity, the fast quantum part will be the electromagnetic fields modes in cavity.
The Aharonov-Bohm effect (that Todd "WarpTech" discussed in his posts) can be interpreted as a geometrical phase factor of the kind postulated by Berry.
LOL...I knew I forgot something...I was going to write that on the beam :oThe only Plank I see around here is rfmwguy's floobie-stick 8)http://arxiv.org/abs/quant-ph/0603073
About berry phases and forces.
Following the article, the slow classical part will be the cavity, the fast quantum part will be the electromagnetic fields modes in cavity.
The Aharonov-Bohm effect (that Todd "WarpTech" discussed in his posts) can be interpreted as a geometrical phase factor of the kind postulated by Berry.
The only Plank I see around here is rfmwguy's floobie-stick 8)http://arxiv.org/abs/quant-ph/0603073
About berry phases and forces.
Following the article, the slow classical part will be the cavity, the fast quantum part will be the electromagnetic fields modes in cavity.
The Aharonov-Bohm effect (that Todd "WarpTech" discussed in his posts) can be interpreted as a geometrical phase factor of the kind postulated by Berry.
@rfmwguy - Newbie poster here. Followed all the threads and have a suggestion. From an experimental standpoint, it would be useful to collect multiple data sets (in your case, the 10 min video of the laser dot position). Put simply, run the test 3 separate times, with a delay (an hour or two) between runs. Then post the 3 videos. This would allow those evaluating the data to see if there are repeatable patterns. Once a particular configuration has been torn down and reconfigured, it's non-trivial to recreate it exactly for verification purposes.Thanks, my first view of the vid appears to show something happening that wasn't there yesterday. If so, you bet I will start tweaking the setup, such as a new mirror, camera, target and who knows what else besides a longer static recording time. If movement confirmed, I'll not modify NSF-1701 from its current configuration.
Please keep up the excellent work!
Kurt
@rfmwguy - Newbie poster here. Followed all the threads and have a suggestion. From an experimental standpoint, it would be useful to collect multiple data sets (in your case, the 10 min video of the laser dot position). Put simply, run the test 3 separate times, with a delay (an hour or two) between runs. Then post the 3 videos. This would allow those evaluating the data to see if there are repeatable patterns. Once a particular configuration has been torn down and reconfigured, it's non-trivial to recreate it exactly for verification purposes.Thanks, my first view of the vid appears to show something happening that wasn't there yesterday. If so, you bet I will start tweaking the setup, such as a new mirror, camera, target and who knows what else besides a longer static recording time. If movement confirmed, I'll not modify NSF-1701 from its current configuration.
Please keep up the excellent work!
Kurt
Great work rfmwguy!
Here is a montage of how the region of interest looks throughout the whole movie (stretched in Y to make things clearer).
@rfmwguy - Newbie poster here. Followed all the threads and have a suggestion. From an experimental standpoint, it would be useful to collect multiple data sets (in your case, the 10 min video of the laser dot position). Put simply, run the test 3 separate times, with a delay (an hour or two) between runs. Then post the 3 videos. This would allow those evaluating the data to see if there are repeatable patterns. Once a particular configuration has been torn down and reconfigured, it's non-trivial to recreate it exactly for verification purposes.Thanks, my first view of the vid appears to show something happening that wasn't there yesterday. If so, you bet I will start tweaking the setup, such as a new mirror, camera, target and who knows what else besides a longer static recording time. If movement confirmed, I'll not modify NSF-1701 from its current configuration.
Please keep up the excellent work!
Kurt
After the oscillations from starting the tests settle down, the laser is pointing lower on the target. I guess that would be the new 'zero' for each test. From there, I don't see any movement.Indeed, also my observation. It's as if the floobiestick is permanently bent after a given trial. The obvious response to this is to call for more detailed calibration. There seems to be excess "stickiness" in the system.
Of course, my technique of placing sticky notes on my monitor might not be the most accurate method. :)
It's time for the data analysis group to zoom in and examine it frame by frame.
Once I see the video from croppa and others, I'll feel more confident in this configuration showing more movement. Only a guess, but the slow tracking downward is thermal lift even with mesh. If it tracks the same as yesterday, we have an answer. However, I did notice more movement overall this time.After the oscillations from starting the tests settle down, the laser is pointing lower on the target. I guess that would be the new 'zero' for each test. From there, I don't see any movement.Indeed, also my observation. It's as if the floobiestick is permanently bent after a given trial. The obvious response to this is to call for more detailed calibration. There seems to be excess "stickiness" in the system.
Of course, my technique of placing sticky notes on my monitor might not be the most accurate method. :)
It's time for the data analysis group to zoom in and examine it frame by frame.
Deflection direction is the same as in test #1 (downward laser, upward frustum, therefore big-end-forward). There also seems to be a greater deflection with this new magnetron mount.
Fields are small within the closed oven for the display, etc. Would be surprised it it impacted the small amount of magnetic material on the test stand. Static is possible, but we are over 50% RH so not likely to have an impact...all imo only.Great work rfmwguy!
Here is a montage of how the region of interest looks throughout the whole movie (stretched in Y to make things clearer).
The microwave oven has a timer on it so it will be drawing mains power through a transformer even when the magnetron is not transmitting. Transformers give off a magnetic field. Was the oven powered up when the weight was used to calibrate the laser?
Alternative possibility. Static electricity can build up slowly.
Please include temps on big and little end walls as well as side walls, see if you can can a noticeable temp differential along the side and end walls.Only temp over ambient was on board where mag was mounted. Sides and bottom were near ambient in static thermal tests.
After the oscillations from starting the tests settle down, the laser is pointing lower on the target. I guess that would be the new 'zero' for each test. From there, I don't see any movement.Indeed, also my observation. It's as if the floobiestick is permanently bent after a given trial. The obvious response to this is to call for more detailed calibration. There seems to be excess "stickiness" in the system.
Of course, my technique of placing sticky notes on my monitor might not be the most accurate method. :)
It's time for the data analysis group to zoom in and examine it frame by frame.
Deflection direction is the same as in test #1 (downward laser, upward frustum, therefore big-end-forward). There also seems to be a greater deflection with this new magnetron mount.
Yet, each measure Q differently...see my point?
I just had a thought. In the past, I have weighed a HV capacitor charged and discharged, on a balance beam much smaller than this one. Regardless of polarity, when the capacitor is charged, it is heavier and the balance beam would tip.Sorry, but I'm calling nonsense on that lot, as a cursory calculation shows. Take a 2 mF capacitor charged to 10 kV. That's 100 kJ or a mass equivalent of 1 nanogram.. The fact that you did not have that precision but think you did illustrates how difficult is experimental physics, and how easily fooled even smart people can be.
Here, when the microwave is turned on, the frustum is charging with energy, like a capacitor. It's weight will increase due to the energy input to the system, M = E/c^2. When the frustum is charged, it's heavier. This is only a concern when using a balance beam. When using a rotary test setup, this is not an issue. However, like buoyancy, it can be subtracted off by turning it upside down but a mesh isn't going to prevent it.
Todd
I just had a thought. In the past, I have weighed a HV capacitor charged and discharged, on a balance beam much smaller than this one. Regardless of polarity, when the capacitor is charged, it is heavier and the balance beam would tip.Sorry, but I'm calling nonsense on that lot, as a cursory calculation shows. Take a 2 mF capacitor charged to 10 kV. That's 100 kJ or a mass equivalent of 1 nanogram.. The fact that you did not have that precision but think you did illustrates how difficult is experimental physics, and how easily fooled even smart people can be.
Here, when the microwave is turned on, the frustum is charging with energy, like a capacitor. It's weight will increase due to the energy input to the system, M = E/c^2. When the frustum is charged, it's heavier. This is only a concern when using a balance beam. When using a rotary test setup, this is not an issue. However, like buoyancy, it can be subtracted off by turning it upside down but a mesh isn't going to prevent it.
Todd
What is wrong with you? You just made it about a hundred thousand times worse!I just had a thought. In the past, I have weighed a HV capacitor charged and discharged, on a balance beam much smaller than this one. Regardless of polarity, when the capacitor is charged, it is heavier and the balance beam would tip.Sorry, but I'm calling nonsense on that lot, as a cursory calculation shows. Take a 2 mF capacitor charged to 10 kV. That's 100 kJ or a mass equivalent of 1 nanogram.. The fact that you did not have that precision but think you did illustrates how difficult is experimental physics, and how easily fooled even smart people can be.
Here, when the microwave is turned on, the frustum is charging with energy, like a capacitor. It's weight will increase due to the energy input to the system, M = E/c^2. When the frustum is charged, it's heavier. This is only a concern when using a balance beam. When using a rotary test setup, this is not an issue. However, like buoyancy, it can be subtracted off by turning it upside down but a mesh isn't going to prevent it.
Todd
This was a ~2.5 mil piece of plexiglass, covered in aluminum foil, both sides, about 24" on a side. I had it balanced on a stick of balsa wood, connected to a rectified 12kV neon sign transformer. The result was repeatable. When on, the balance tipped toward the capacitor. I didn't actually measure a weight, just a deflection. It was tiny, but visible to the naked eye, and I wasn't using a laser and mirror to magnify the deflection. I just looked at the height above the table, with a ruler at the other end of the stick. The balsa wasn't more than 4' long.
Todd
Early days for drawing any conclusions. Of course, you try the big and obvious things first. Repositioning the magnetron was one such trial. I'd suggest another big and obvious one would be to flip the frustum over so now it's small side up. Does the thrust reverse? That is what Iulian found.I definitely second that!
Early days for drawing any conclusions. Of course, you try the big and obvious things first. Repositioning the magnetron was one such trial. I'd suggest another big and obvious one would be to flip the frustum over so now it's small side up. Does the thrust reverse? That is what Iulian found.
Early days for drawing any conclusions. Of course, you try the big and obvious things first. Repositioning the magnetron was one such trial. I'd suggest another big and obvious one would be to flip the frustum over so now it's small side up. Does the thrust reverse? That is what Iulian found.I agree that the next step should be to flip the truncated cone so that the opposite end is pointing up.
...1) There is some unexpected movement that is worth pursuing at a higher measurement resolution; well below 200 mg....I agree. Since the movement is at the threshold or below the threshold of what can be measured at the moment, I would only test at 100% power from now on.
...2) FT1 and FT2 produces what I believe to be thermal lift as the magnetron goes through its 6 minute total testing cycle, equivalent to approximately 500 mg....
Early days for drawing any conclusions. Of course, you try the big and obvious things first. Repositioning the magnetron was one such trial. I'd suggest another big and obvious one would be to flip the frustum over so now it's small side up. Does the thrust reverse? That is what Iulian found.I agree that the next step should be to flip the truncated cone so that the opposite end is pointing up.
Concerning the power settings: it was a good idea for RFMWGUY to plan to test the power at different settings before we knew what the test results were going to be. Why? Because the claimed results from Yang and Shawyer are by several orders of magnitude higher than those reported by Tajmar and by NASA. But now that we know that the results are at the very threshold of the measuring ability of this set-up, wouldn't it make sense to only test at 100% (maximum) power setting?
What is the point of testing at lower power setting when even the 100% maximum power setting gives results that are at the threshold of the measurement capability?
I would only test at 100% maximum power setting from now on. I would conduct the same or more number of power on/ power off time settings. This would allow us to look at some statistical distribution, by only testing at 100% maximum power and having several tests power on/ power off/power on/power off. Testing at only 100% power setting, and conducting a number of such tests would allow to further differentiate between the slow drift that appears unrelated to power, and any other movements.
...1) There is some unexpected movement that is worth pursuing at a higher measurement resolution; well below 200 mg....I agree. Since the movement is at the threshold or below the threshold of what can be measured at the moment, I would only test at 100% power from now on....2) FT1 and FT2 produces what I believe to be thermal lift as the magnetron goes through its 6 minute total testing cycle, equivalent to approximately 500 mg....
I completely agree. The slow drift looks like a slow thermal artifact and not related to the electromagnetic power on/power off. We need to distinguish between the slow drift that appears unrelated to the electromagnetic power and other movements that may not be so explained away.
////////////////////////////////////
I hope that you will continue with your experiments :)
Congratulations again for a very impressive experiment !
...1) There is some unexpected movement that is worth pursuing at a higher measurement resolution; well below 200 mg....I agree. Since the movement is at the threshold or below the threshold of what can be measured at the moment, I would only test at 100% power from now on....2) FT1 and FT2 produces what I believe to be thermal lift as the magnetron goes through its 6 minute total testing cycle, equivalent to approximately 500 mg....
I completely agree. The slow drift looks like a slow thermal artifact and not related to the electromagnetic power on/power off. We need to distinguish between the slow drift that appears unrelated to the electromagnetic power and other movements that may not be so explained away.
////////////////////////////////////
I hope that you will continue with your experiments :)
Congratulations again for a very impressive experiment !
It seems to me that the advantage of running at lower power is that it cycles on/off without rfmwguy being close to the setup. As I understand it the on cycles are full power anyway and only the overall proportion of on time is reduced. There are definite oscillations associated with the start of these runs (you can see these more easily in the unstretched montage shown here, as well as the raw video). I suspect these are air currents associated with rfmwguy moving past the apparatus after triggering the run but can't say for sure.
As other have noted, a great improvement to the current setup would be the ability to trigger it from a distance, although I imagine that's not trivial.
As other have noted, a great improvement to the current setup would be the ability to trigger it from a distance, although I imagine that's not trivial.It should be really easy to trigger remotely. Ultimately the microwave control panel has a Start button, a membrane switch, you can just solder onto the circuit board and run two long wires wherever you like attached to a remote start momentary contact button. Preferably something dramatic. http://www.amazon.com/Lock-Switch-Mushroom-Button-Station/dp/B008ZY9CXE (http://www.amazon.com/Lock-Switch-Mushroom-Button-Station/dp/B008ZY9CXE).
You need to do a survey of your frustum's resonant frequencies. Eagleworks did it. You need to characterise your frustum so you know what you are dealing with and what sort of load your magnetron is driving.
You need to do a survey of your frustum's resonant frequencies. Eagleworks did it. You need to characterise your frustum so you know what you are dealing with and what sort of load your magnetron is driving.
Agreed. As more experiments are run it is clear that the 'magic' parameters for large measurable forces must be in a very small range. (as an aside, to me that makes it questionable that Shawyer found them in the first place).
As the search begins, it will be more and more important to characterize each step of the way to ensure you are working with what you think you are working with.
Pic Caption: FT2 setup this AM. Looking down with magnetron mounted on big base, small base is down. Electrodes dipping down into copper cups will Galinstan. Note location of black laser pointer.Is that blue masking tape holding the laser pointer in place? If so, that will be really prone to slowly drooping.
Agreed.
Shawyer's 1st EMDrive, that he reported on, was highly tunable as attached.
So he clearly KNEW of the variables and designed in methods to deal with them, which says to me this was not his 1st experimental build but his 1st successful experimental build.
Shawyer did have at least a decade or 2 of microwave experience before he built his 1st device, so he had a decent real world microwave background knowledge to work from.
His Experimental unit could tune the top plate, the feed waveguide impedance, and the amount of the bottom dielectric insertion into the frustum for maximum Force generation. Says to me he knew well the devil he was working with. And this was in 2000 - 2002.
...
If that is the case, we'll have to look at this as more than an instantaneous burst of motion.
As a side note, when I came back near the experiment at the end of the test run, I felt no warmer air than when I started, but did notice an unusual "ambience'" to the air. Best way I can describe it as metallic, ionized air. This is not scientific obviously, just a minor observation I did not notice during static testing.
Agreed.
Shawyer's 1st EMDrive, that he reported on, was highly tunable as attached.
So he clearly KNEW of the variables and designed in methods to deal with them, which says to me this was not his 1st experimental build but his 1st successful experimental build.
Shawyer did have at least a decade or 2 of microwave experience before he built his 1st device, so he had a decent real world microwave background knowledge to work from.
His Experimental unit could tune the top plate, the feed waveguide impedance, and the amount of the bottom dielectric insertion into the frustum for maximum Force generation. Says to me he knew well the devil he was working with. And this was in 2000 - 2002.
I agree. Shawyer's experience surely showed him that he needed to be able to tune the most parameters he could.
And he came with a solution that could tune the geometry (vital for achieving resonance or the "right stuff") and possibly the magnetron's frequency. In this way he just needed to build one test device for covering a big swath of combinations, instead of building one fixed model, seeing it didn't work well or at all, and then build another and another.
rfmwguy -
I just spent some time trying to reconcile the results you have with some kind of expectation of how the setup should respond to a thrust.
The apparent slow movement of the balance beam seems simplest to fit to thermal (probably air current related) forces building as the temperature rises. That's also consistent with the apparent direction of the force being upwards in both cases. There could still be thrust, but thermal effects will clutter the results. What's more, I think that's intrinsic to the balance-beam approach, where the measured thrust is necessarily vertical. It's also hard to net them out in your setup, because the position of the magnetron means that thermal forces will be asymmetrical as you invert the frustrum.
If the effect is real, there is no reason to expect it to build over minutes. When you placed the weights on the beam, the response was comparatively immediate. Therefore, a 'kick' on switch-on followed by a slow build due to thermal might be something to look for. I'll go back and peer at that for a while!
My son the engineer commented that he would prefer to be looking for a horizontal force, otherwise thermals will be a confounding factor. Maybe the rotating table of Shawyer's wasn't such a bad idea....
R.
Early days for drawing any conclusions. Of course, you try the big and obvious things first. Repositioning the magnetron was one such trial. I'd suggest another big and obvious one would be to flip the frustum over so now it's small side up. Does the thrust reverse? That is what Iulian found.
You are correct, ON or OFF. The 30% relates only to the duration of ON during the test period.Early days for drawing any conclusions. Of course, you try the big and obvious things first. Repositioning the magnetron was one such trial. I'd suggest another big and obvious one would be to flip the frustum over so now it's small side up. Does the thrust reverse? That is what Iulian found.I agree that the next step should be to flip the truncated cone so that the opposite end is pointing up.
Concerning the power settings: it was a good idea for RFMWGUY to plan to test the power at different settings before we knew what the test results were going to be. Why? Because the claimed results from Yang and Shawyer are by several orders of magnitude higher than those reported by Tajmar and by NASA. But now that we know that the results are at the very threshold of the measuring ability of this set-up, wouldn't it make sense to only test at 100% (maximum) power setting?
What is the point of testing at lower power setting when even the 100% maximum power setting gives results that are at the threshold of the measurement capability?
I would only test at 100% maximum power setting from now on. I would conduct the same or more number of power on/ power off time settings. This would allow us to look at some statistical distribution, by only testing at 100% maximum power and having several tests power on/ power off/power on/power off. Testing at only 100% power setting, and conducting a number of such tests would allow to further differentiate between the slow drift that appears unrelated to power, and any other movements.
@rfmwguy - correct me if I am wrong, but I thought the magnetron had only 2 power settings, "off" and 100%. It is the microwave oven control that runs the magnetron at 100% power, but only 30% of the time achieving what is called 30% power level. And it is 30% for cooking, but for the thruster, it is 100% for 30% of the time.
And on a side note, why 30%, why not 50%? Have you been able to calculate the resonate frequency of your foobie stick set-up? It might be interesting if it is possible to drive your balance beam at resonance.
Good point, I thought about that, but the tape had been in place for about 72 hours, less likely to droop over a 6 min test. I'll put a mirror in place of it and securely bolt it on next time.
Agreed.
Shawyer's 1st EMDrive, that he reported on, was highly tunable as attached.
So he clearly KNEW of the variables and designed in methods to deal with them, which says to me this was not his 1st experimental build but his 1st successful experimental build.
Shawyer did have at least a decade or 2 of microwave experience before he built his 1st device, so he had a decent real world microwave background knowledge to work from.
His Experimental unit could tune the top plate, the feed waveguide impedance, and the amount of the bottom dielectric insertion into the frustum for maximum Force generation. Says to me he knew well the devil he was working with. And this was in 2000 - 2002.
I agree. Shawyer's experience surely showed him that he needed to be able to tune the most parameters he could.
And he came with a solution that could tune the geometry (vital for achieving resonance or the "right stuff") and possibly the magnetron's frequency. In this way he just needed to build one test device for covering a big swath of combinations, instead of building one fixed model, seeing it didn't work well or at all, and then build another and another.
Using Shapeways to 3D Print a Tiny, Fuel Free Microwave EMDrive Thruster?
http://forum.nasaspaceflight.com/index.php?topic=33141.msg1420297#msg1420297
Tolerances are handable but good high power amps are expensive :-\Using Shapeways to 3D Print a Tiny, Fuel Free Microwave EMDrive Thruster?
http://forum.nasaspaceflight.com/index.php?topic=33141.msg1420297#msg1420297
The challenge is in getting high power at 24GHz. Otherwise 3d printing is a great fabrication method for small devices because the tolerances are generally pretty low.
... but good high power amps are expensive :-\
Yes there are cheap PLL sources for direct synthesis and amps available for 2.4GHz :D... but good high power amps are expensive :-\
For sure. Which is why I went for a $450 100W 0.5 - 2.5GHz Rf amp with forward & reverse power monitoring and 32 stage (5 bit) adjustable output level control.
The sweetness is in the data and what it will reveal about the operational characteristics of an accelerating EMDrive.
Using Shapeways to 3D Print a Tiny, Fuel Free Microwave EMDrive Thruster?
http://forum.nasaspaceflight.com/index.php?topic=33141.msg1420297#msg1420297
For sure. Which is why I went for a $450 100W 0.5 - 2.5GHz Rf amp with forward & reverse power monitoring and 32 stage (5 bit) adjustable output level control.
The sweetness is in the data and what it will reveal about the operational characteristics of an accelerating EMDrive.
As other have noted, a great improvement to the current setup would be the ability to trigger it from a distance, although I imagine that's not trivial.
For sure. Which is why I went for a $450 100W 0.5 - 2.5GHz Rf amp with forward & reverse power monitoring and 32 stage (5 bit) adjustable output level control.
The sweetness is in the data and what it will reveal about the operational characteristics of an accelerating EMDrive.
Is this one of the amplifiers you bought in bulk? If so, are you willing to sell one of them?
...1) There is some unexpected movement that is worth pursuing at a higher measurement resolution; well below 200 mg....I agree. Since the movement is at the threshold or below the threshold of what can be measured at the moment, I would only test at 100% power from now on....2) FT1 and FT2 produces what I believe to be thermal lift as the magnetron goes through its 6 minute total testing cycle, equivalent to approximately 500 mg....
I completely agree. The slow drift looks like a slow thermal artifact and not related to the electromagnetic power on/power off. We need to distinguish between the slow drift that appears unrelated to the electromagnetic power and other movements that may not be so explained away.
////////////////////////////////////
I hope that you will continue with your experiments :)
Congratulations again for a very impressive experiment !
It seems to me that the advantage of running at lower power is that it cycles on/off without rfmwguy being close to the setup. As I understand it the on cycles are full power anyway and only the overall proportion of on time is reduced. There are definite oscillations associated with the start of these runs (you can see these more easily in the unstretched montage shown here, as well as the raw video). I suspect these are air currents associated with rfmwguy moving past the apparatus after triggering the run but can't say for sure.
As other have noted, a great improvement to the current setup would be the ability to trigger it from a distance, although I imagine that's not trivial.
Cycling on/off at less than 100% full power constantly on all the cycle time has this undeniable drawback:
the response at the moment is so small that it is at the threshold or below the threshold of what can be measured. Therefore one should only test with 100% power constantly on all the cycle time in order to try to maximize the response. Anything less than 100% power on during the ON cycle will just result in amplifying the relative level of "noise" (thermal and other artifacts) and minimizing the relative level of any possible signal that is not an artifact.
...1) There is some unexpected movement that is worth pursuing at a higher measurement resolution; well below 200 mg....I agree. Since the movement is at the threshold or below the threshold of what can be measured at the moment, I would only test at 100% power from now on....2) FT1 and FT2 produces what I believe to be thermal lift as the magnetron goes through its 6 minute total testing cycle, equivalent to approximately 500 mg....
I completely agree. The slow drift looks like a slow thermal artifact and not related to the electromagnetic power on/power off. We need to distinguish between the slow drift that appears unrelated to the electromagnetic power and other movements that may not be so explained away.
////////////////////////////////////
I hope that you will continue with your experiments :)
Congratulations again for a very impressive experiment !
It seems to me that the advantage of running at lower power is that it cycles on/off without rfmwguy being close to the setup. As I understand it the on cycles are full power anyway and only the overall proportion of on time is reduced. There are definite oscillations associated with the start of these runs (you can see these more easily in the unstretched montage shown here, as well as the raw video). I suspect these are air currents associated with rfmwguy moving past the apparatus after triggering the run but can't say for sure.
As other have noted, a great improvement to the current setup would be the ability to trigger it from a distance, although I imagine that's not trivial.
Cycling on/off at less than 100% full power constantly on all the cycle time has this undeniable drawback:
the response at the moment is so small that it is at the threshold or below the threshold of what can be measured. Therefore one should only test with 100% power constantly on all the cycle time in order to try to maximize the response. Anything less than 100% power on during the ON cycle will just result in amplifying the relative level of "noise" (thermal and other artifacts) and minimizing the relative level of any possible signal that is not an artifact.
The point seems to be getting missed is that the microwave operates at 100% power at all times. The "power setting" is merely a cycle time within the overall time of the run. A 30% power setting on a 5 minute run means that the machine cycles on and off so that it is operating only 30% of the time. 70% setting means it operates over 70% of the timer interval.
The strength of the microwave, 650 watt, 1000 watt, 1200 watt refers to the power output while running.
Cycling on/off at less than 100% full power constantly on all the cycle time has this undeniable drawback:
the response at the moment is so small that it is at the threshold or below the threshold of what can be measured.
Tolerances are handable but good high power amps are expensive :-\Using Shapeways to 3D Print a Tiny, Fuel Free Microwave EMDrive Thruster?
http://forum.nasaspaceflight.com/index.php?topic=33141.msg1420297#msg1420297
The challenge is in getting high power at 24GHz. Otherwise 3d printing is a great fabrication method for small devices because the tolerances are generally pretty low.
Turning machine is fine for this dimensions ;) don't need a 3D printer.
EDIT: Nobody knows what produce higher thrust, higher or lower frequencies(If these are no measurement artefacts). I remember there was a discussion about, here some times ago.
So why run the power cycling on and off, being off 70% of the time ????
Have been trying to find very specific operating specs on magnetrons without much success. IOW, I know manufacturers put cheap conventional oven thermal switches on the heatsink that trip at 160 deg C, but nowhere can I find magnetron tube temp specs. Putting a thermal sensor on a heatsink simply retards the temp rise from the tube itself. If anyone can pull up the core (tube) operating temperature, it would be appreciated.So why run the power cycling on and off, being off 70% of the time ????
That made sense when checking to see how hot the magnetron would get before actual testing.
You're right, tests should be conducted at 100%. Cycling the power introduces multiple thrust impulses (real, if any, and thermal). Cooling between cycles confuses the situation.
Still, rfmwguy should be careful not to overheat the magnetron on long test runs. Maybe some engineering runs should be done to see how long the magnetron can be safely operated.
So why run the power cycling on and off, being off 70% of the time ????
That made sense when checking to see how hot the magnetron would get before actual testing.
You're right, tests should be conducted at 100%. Cycling the power introduces multiple thrust impulses (real, if any, and thermal). Cooling between cycles confuses the situation.
Still, rfmwguy should be careful not to overheat the magnetron on long test runs. Maybe some engineering runs should be done to see how long the magnetron can be safely operated.
So why run the power cycling on and off, being off 70% of the time ????
That made sense when checking to see how hot the magnetron would get before actual testing.
You're right, tests should be conducted at 100%. Cycling the power introduces multiple thrust impulses (real, if any, and thermal). Cooling between cycles confuses the situation.
Still, rfmwguy should be careful not to overheat the magnetron on long test runs. Maybe some engineering runs should be done to see how long the magnetron can be safely operated.
I'd really like to see the deflection from a clean 30% run with the balance left undisturbed for 15-30 minutes afterwards so that it returns to the initial condition, the same for a 100% run and then a 30% + 100% run (like rfmguy has been doing) with balance left to return to initial condition. I'd like to make sure the stickiness is part of the rig and not the effect.
....I must say that the suspected thermal lift is far more than I expected using mesh. I cannot imagine any other vertical force. Well, antigravity, but that's about as likely as bigfoot knocking on my door...The mesh on the lateral conical walls reduced the effect of air density decreasing inside the truncated cone.
....I must say that the suspected thermal lift is far more than I expected using mesh. I cannot imagine any other vertical force. Well, antigravity, but that's about as likely as bigfoot knocking on my door...The mesh on the lateral conical walls reduced the effect of air density decreasing inside the truncated cone.
However, as you measured, the highest temperature, by far occurs at the magnetron instead of inside the cone. Therefore the air density is reduced next to the magnetron. This produces natural convection thermal currents, due to the difference in density of the hot air next to the magnetron, with the ambient air. This natural convection thermal current produced by the magnetron is the one responsible for the lifting force.
(...) I expect we are all hoping for a more definitive laser spot trace from future runs. (...)Yes, perhaps we could use something like this:
panasonic http://www.rell.com/filebase/en/tsrc/Datasheets/2M244-M10G.pdfHave been trying to find very specific operating specs on magnetrons without much success. IOW, I know manufacturers put cheap conventional oven thermal switches on the heatsink that trip at 160 deg C, but nowhere can I find magnetron tube temp specs. Putting a thermal sensor on a heatsink simply retards the temp rise from the tube itself. If anyone can pull up the core (tube) operating temperature, it would be appreciated.So why run the power cycling on and off, being off 70% of the time ????
That made sense when checking to see how hot the magnetron would get before actual testing.
You're right, tests should be conducted at 100%. Cycling the power introduces multiple thrust impulses (real, if any, and thermal). Cooling between cycles confuses the situation.
Still, rfmwguy should be careful not to overheat the magnetron on long test runs. Maybe some engineering runs should be done to see how long the magnetron can be safely operated.
Flip the mirror 90 degrees. It's a camera tripod. There should be a 90 degree flip adjustment. Turn the vertical line into a horizontal line that way.Early days for drawing any conclusions. Of course, you try the big and obvious things first. Repositioning the magnetron was one such trial. I'd suggest another big and obvious one would be to flip the frustum over so now it's small side up. Does the thrust reverse? That is what Iulian found.
I say, he needs to sharpen up that laser before he does anymore tests. The BIG BLOB of red light with lines crossing in front of it, not along side of it, is not accurate enough to tell what is going on. A sharp pencil at the end of the balance beam would be more accurate.
I also suggest running the full power test first, to heat up the air, before doing the 30% test where it cycles on and off. Hopefully, that will eliminate the buoyancy effects we're seeing.
Todd
....I must say that the suspected thermal lift is far more than I expected using mesh. I cannot imagine any other vertical force. Well, antigravity, but that's about as likely as bigfoot knocking on my door...The mesh on the lateral conical walls reduced the effect of air density decreasing inside the truncated cone.
However, as you measured, the highest temperature, by far occurs at the magnetron instead of inside the cone. Therefore the air density is reduced next to the magnetron. This produces natural convection thermal currents, due to the difference in density of the hot air next to the magnetron, with the ambient air. This natural convection thermal current produced by the magnetron is the one responsible for the lifting force.
Hi, Another noob here lurking.. :)
Just saw this
http://phys.org/news/2015-08-theory-radiationless-revolution.html (http://phys.org/news/2015-08-theory-radiationless-revolution.html)
With the talk of poloidal fields this new theory seems relevant, hope it's useful..
As a side note, when I came back near the experiment at the end of the test run, I felt no warmer air than when I started, but did notice an unusual "ambiance'" to the air. Best way I can describe it as metallic, ionized air. This is not scientific obviously, just a minor observation I did not notice during static testing.
If air is ionized then it can be accelerated, it is a good explanation why in previous tests the thrust seem to decrease in imperfect vacuum.
Hi, Another noob here lurking.. :)
Just saw this
http://phys.org/news/2015-08-theory-radiationless-revolution.html (http://phys.org/news/2015-08-theory-radiationless-revolution.html)
With the talk of poloidal fields this new theory seems relevant, hope it's useful..
Came on here to post this as well, though I am certainly not across the physics on this.
Here is the Nature paper:
http://www.nature.com/ncomms/2015/150827/ncomms9069/full/ncomms9069.html
Yes, we could put numbers on the thermal convection forces (*) and compare with the electromagnetic force to arrive at the conclusion that the long-term drift that doesn't recover by the end of the test cannot be an electromagnetic effect.....I must say that the suspected thermal lift is far more than I expected using mesh. I cannot imagine any other vertical force. Well, antigravity, but that's about as likely as bigfoot knocking on my door...The mesh on the lateral conical walls reduced the effect of air density decreasing inside the truncated cone.
However, as you measured, the highest temperature, by far occurs at the magnetron instead of inside the cone. Therefore the air density is reduced next to the magnetron. This produces natural convection thermal currents, due to the difference in density of the hot air next to the magnetron, with the ambient air. This natural convection thermal current produced by the magnetron is the one responsible for the lifting force.
That is an interesting thought not to be discarded out of hand, but has anyone put numbers on the force detected? Has anyone put numbers on the drag force limits of the "natural convection thermal currents?" Has anyone put numbers on the lift force response (time constant) of a hot air balloon heated by 1 kw?
I expect we are all hoping for a more definitive laser spot trace from future runs. Still, I think some bounds could be established for some of these error sources. It is one thing to say, "I think it is that." It is quite a different thing to say, "The numbers show that it is that within these limits, and here are my calculations," as Warptech does.
And of course I'm as guilty as anyone.
Morning coffee musings - I have to comment that both here and on reddit (maybe elsewhere?) there is a lot of interesting back and forth on NSF-1701 2 flight tests. Most commentary has been pretty useful IMO and that which is not is quickly pointed out by other posters. Perhaps this type of collaborative discussion is going on about other things on the interwebs, but I've not seen it.I have no problem with sharing or being open. But right now I'm faced with putting this thing together right. Spending time on the blogs is a great research mindmeld for the basics but now it's come down to a one on one.
Look at the length of these 4 threads and the new daily threads on reddit. Pretty indicative that the project has tons of grass-roots, scientific interest out there. All done without national advertising or institutional promotion.
Look forward to more from other experiments and hope they keep the open disclosure movement going. Any real data, successful or otherwise is more than we have right now.
p.s. My advice to other builders? Check your ego at the door. Open disclosure with experiments is not for those with insecurity issues. Just providing data is rewarding enough and people out there appreciate it. So get those cameras rolling and jump into the hot tub...the water's fine ;)
"Frustum" courtesy of: http://www.sears.com/swimline-pooltunes-floating-speaker-light/p-SPM7786027802?hlSellerId=13467&sid=IDx20110310x00001i&kpid=SPM7786027802&kispla=SPM7786027802&mktRedirect=y
I think that the fact that the long-term drift in these latest tests cannot be an electromagnetic effect is so clear that it is not necessary to repeat all those calculations. This is kind of self-evident after those previous discussions. Anyway, it seems that people thinking that the long-term not-recovered-by-the-end-of-the-test effect can be an electromagnetic effect are not going to be convinced by resuscitating those thermal calculations. So, I am not going to repeat them, repeating them seems like a futile exercise.
SeeShells and The Traveller are close to running their DIY experiments. Aachen seem to have gone quiet for a while. SLOtown students are chugging along too. Together with EW and rfmwguy, that makes six currently-active experiments. Did I miss any?
Is the wiki current?
http://emdrive.wiki/Building
There's a lot more than 6 there.
I agree with the big picture you quoted and I'm almost obsessed with squeezing the best I can from a DYI point and putting a thumbtack on it.SeeShells and The Traveller are close to running their DIY experiments. Aachen seem to have gone quiet for a while. SLOtown students are chugging along too. Together with EW and rfmwguy, that makes six currently-active experiments. Did I miss any?
Is the wiki current?
http://emdrive.wiki/Building
There's a lot more than 6 there.
There are also experiments that have already been done, that had null results but have not yet been properly documented in the EM Drive wiki for experimental results, for example: Mulletron's experiment who was the leader in such experiments, had null results documented in early threads, also the experiments with the experimenter that had constant cross-section waveguide and was using dielectric inserts, gave null results.
I understand that null results in these experiments don't close the book, as any experiment is limited on what can be tested (type of force measurement, set-up, etc.), but as SeeShell, says, "there is no bad data" and we should not forget those null results as well, as they are part of the big picture.
The big picture that is emerging is that if there is any EM Drive force, it is either zero or its force/InputPower magnitude is of the magnitude reported by NASA and by Dresden University (Tajmar) but not at all the magnitudes reported by Shawyer and Yang - who nobody has been able to reproduce-
The force/InputPower reported by Iulian Berca was similar to the one reported by NASA.
I shall confess that the ozone smell rfmguy talked about is worrying me, if in the magnetron we have a kind of corona effect the apparatus could take an electrostatic charge even after the magnetron is shut down
Has anyone contacted Yang with a view to touring her lab?
Yes, Chinese military connections, I know. It's a Hail Mary type question.
Which raises the question - if you're behind the Great Firewall of China, can you access NSF?
Or even (given the fact that Chinese are banned by NASA from visiting ISS) does NASA block China access to NSF?
SeeShells and The Traveller are close to running their DIY experiments. Aachen seem to have gone quiet for a while. SLOtown students are chugging along too. Together with EW and rfmwguy, that makes six currently-active experiments. Did I miss any?
Is the wiki current?
http://emdrive.wiki/Building
There's a lot more than 6 there.
There are also experiments that have already been done, that had null results but have not yet been properly documented in the EM Drive wiki for experimental results
The big picture that is emerging is that if there is any EM Drive force, it is either zero or its force/InputPower magnitude is of the very small magnitude reported by NASA (~0.001 Newton/KiloWatt) and by Dresden University (Tajmar) (0.00003 to 0.00013 Newton/KiloWatt) but not at all the thousands of times greater magnitudes reported by Shawyer (0.4 Newton/KiloWatt) and Yang (1 Newton/KiloWatt) - who nobody has been able to reproduce-
I'll hate myself for saying this later, but: Unreasonable Q factors is my guess.SeeShells and The Traveller are close to running their DIY experiments. Aachen seem to have gone quiet for a while. SLOtown students are chugging along too. Together with EW and rfmwguy, that makes six currently-active experiments. Did I miss any?
Is the wiki current?
http://emdrive.wiki/Building
There's a lot more than 6 there.
There are also experiments that have already been done, that had null results but have not yet been properly documented in the EM Drive wiki for experimental results
The big picture that is emerging is that if there is any EM Drive force, it is either zero or its force/InputPower magnitude is of the very small magnitude reported by NASA (~0.001 Newton/KiloWatt) and by Dresden University (Tajmar) (0.00003 to 0.00013 Newton/KiloWatt) but not at all the thousands of times greater magnitudes reported by Shawyer (0.4 Newton/KiloWatt) and Yang (1 Newton/KiloWatt) - who nobody has been able to reproduce-
Yeah this is an important point. We need to determine what Yang/Shawyer did that the current DIY's are missing.
About this site being accessible in China, no idea, but I can't think for any reason for it not to be. The topics are narrow and focused on space activities, well moderated and far away from anything controversial for the PRC.
SeeShells and The Traveller are close to running their DIY experiments. Aachen seem to have gone quiet for a while. Cal Poly students are chugging along too. Together with EW and rfmwguy, that makes six currently-active experiments. Did I miss any?
Is the wiki current?
http://emdrive.wiki/Building
There's a lot more than 6 there.
We are considering doing two experiments with an industrial magnetron transmitter (c/w waveguide launcher, isolator and waterload) and the University of Saskatoon; either a 100kW continuous into a copper frustrum 932Hz at TE012 (designing cooling system now..) or 5MW 10microsecond pulses. Looks like we would also try having the magnetron fire into the small base or the big base, maybe some with ports on the side. Have some ANSYS modelling going down now. We would also fire the unit towards the ground that buoyant effects are not in play (I don't know why anyone would aim to produce thrust in the up position right now since hot air rising / buoyant is probably the #1 explanation for positive tests). Objective would be to produce a non-null result an order of magnitude above background.That's very ambitious. I assume you mean 932 MHz. With high power and a bespoke cooling system, I assume you cannot make this standalone?SeeShells and The Traveller are close to running their DIY experiments. Aachen seem to have gone quiet for a while. Cal Poly students are chugging along too. Together with EW and rfmwguy, that makes six currently-active experiments. Did I miss any?
Is the wiki current?
http://emdrive.wiki/Building
There's a lot more than 6 there.
I know I'm only an armchair experimenter at this point, but if I may make a suggestion, it's that you first flip the frustum, and after that work on a good impedance match.I'll hate myself for saying this later, but: Unreasonable Q factors is my guess.SeeShells and The Traveller are close to running their DIY experiments. Aachen seem to have gone quiet for a while. SLOtown students are chugging along too. Together with EW and rfmwguy, that makes six currently-active experiments. Did I miss any?
Is the wiki current?
http://emdrive.wiki/Building
There's a lot more than 6 there.
There are also experiments that have already been done, that had null results but have not yet been properly documented in the EM Drive wiki for experimental results
The big picture that is emerging is that if there is any EM Drive force, it is either zero or its force/InputPower magnitude is of the very small magnitude reported by NASA (~0.001 Newton/KiloWatt) and by Dresden University (Tajmar) (0.00003 to 0.00013 Newton/KiloWatt) but not at all the thousands of times greater magnitudes reported by Shawyer (0.4 Newton/KiloWatt) and Yang (1 Newton/KiloWatt) - who nobody has been able to reproduce-
Yeah this is an important point. We need to determine what Yang/Shawyer did that the current DIY's are missing.
If Q is part of their thrust equations, higher Q will yield higher predictive thrust.
(I am so ashamed of myself) 8)
We are considering doing two experiments with an industrial magnetron transmitter (c/w waveguide launcher, isolator and waterload) and the University of Saskatoon; either a 100kW continuous into a copper frustrum 932Hz at TE012 (designing cooling system now..) or 5MW 10microsecond pulses. Looks like we would also try having the magnetron fire into the small base or the big base, maybe some with ports on the side. Have some ANSYS modelling going down now. We would also fire the unit towards the ground that buoyant effects are not in play (I don't know why anyone would aim to produce thrust in the up position right now since hot air rising / buoyant is probably the #1 explanation for positive tests). Objective would be to produce a non-null result an order of magnitude above background.
SeeShells and The Traveller are close to running their DIY experiments. Aachen seem to have gone quiet for a while. SLOtown students are chugging along too. Together with EW and rfmwguy, that makes six currently-active experiments. Did I miss any?
Is the wiki current?
http://emdrive.wiki/Building
There's a lot more than 6 there.
There are also experiments that have already been done, that had null results but have not yet been properly documented in the EM Drive wiki for experimental results, for example: Mulletron's experiment who deserves to be recognized as the true leader in these Do-It-Yourself experiments, had null results documented in early threads, also the experiments with the experimenter that had constant cross-section waveguide and was using dielectric inserts, gave null results.
I understand that null results in these experiments don't close the book, as any experiment is limited on what can be tested (type of force measurement, set-up, etc.), but as Shell, says, "there is no bad data" and we should not forget those null results as well, as they are part of the big picture.
The big picture that is emerging is that if there is any EM Drive force (yes, it may be zero), its force/InputPower magnitude is of the very small magnitude reported by NASA (~0.001 Newton/KiloWatt) and by Dresden University (Tajmar) (0.00003 to 0.00013 Newton/KiloWatt) but not at all the thousands of times greater magnitudes reported by Shawyer (0.4 Newton/KiloWatt) and Yang (1 Newton/KiloWatt) - who nobody has been able to reproduce-
The force/InputPower reported by Iulian Berca was similar to the one reported by NASA.
Think I'll wait for a flip until I solve some measurement resolution issues first. Doing research today and think I'm onto something big. Will post details later.I know I'm only an armchair experimenter at this point, but if I may make a suggestion, it's that you first flip the frustum, and after that work on a good impedance match.I'll hate myself for saying this later, but: Unreasonable Q factors is my guess.SeeShells and The Traveller are close to running their DIY experiments. Aachen seem to have gone quiet for a while. SLOtown students are chugging along too. Together with EW and rfmwguy, that makes six currently-active experiments. Did I miss any?
Is the wiki current?
http://emdrive.wiki/Building
There's a lot more than 6 there.
There are also experiments that have already been done, that had null results but have not yet been properly documented in the EM Drive wiki for experimental results
The big picture that is emerging is that if there is any EM Drive force, it is either zero or its force/InputPower magnitude is of the very small magnitude reported by NASA (~0.001 Newton/KiloWatt) and by Dresden University (Tajmar) (0.00003 to 0.00013 Newton/KiloWatt) but not at all the thousands of times greater magnitudes reported by Shawyer (0.4 Newton/KiloWatt) and Yang (1 Newton/KiloWatt) - who nobody has been able to reproduce-
Yeah this is an important point. We need to determine what Yang/Shawyer did that the current DIY's are missing.
If Q is part of their thrust equations, higher Q will yield higher predictive thrust.
(I am so ashamed of myself) 8)
We are considering doing two experiments with an industrial magnetron transmitter (c/w waveguide launcher, isolator and waterload) and the University of Saskatoon; either a 100kW continuous into a copper frustrum 932Hz at TE012 (designing cooling system now..) or 5MW 10microsecond pulses. Looks like we would also try having the magnetron fire into the small base or the big base, maybe some with ports on the side. Have some ANSYS modelling going down now. We would also fire the unit towards the ground that buoyant effects are not in play (I don't know why anyone would aim to produce thrust in the up position right now since hot air rising / buoyant is probably the #1 explanation for positive tests). Objective would be to produce a non-null result an order of magnitude above background.
I finally finished the loop antenna modeling exercise. Not sure if this is still useful but I will post here. Likely the patterns are the most useful part - as they should give some idea of what modes can be stimulated.Simply beautiful! This was on my bucket list! Love it.
These models and results are made using a version of the NEC codes (specifically EZNEC). NEC antenna modeling is not perfect but if you stay within the constraints it can produce qualitatively useful results. As with all such models, quantitative results are highly dependent on many factors including geometry, signal quality, and many more. Hopefully these will be of use - particularly if the loops are in a spherical chicken in a vacuum.
I modeled three sizes of antenna 1/2, 1, and 2 wavelength circumference, at three different heights - 1/4, 1/2 and 1 wavelength. Also modeled each of these configurations for loops both parallel to and normal to their ground plane.
Sorry for how long this took - as some of you know I have been in the process of retiring and unfortunately this exercise mostly had to take place late in evening after all other boring but necessary stuff had been done. I am now free and hope to start detailed planning for my own DIY experiments soon.
Herman
Interesting news:
http://arxiv.org/pdf/1506.08614v1.pdf
LHC confirms measurements of branching fraction ratio of tau-leptons at BaBar and Belle.
" This result, which is the first measurement of this quantity at a hadron collider, is 2.1 standard deviations larger than the value expected from lepton universality in the Standard Model."
Maybe there is really a "new, unknown kind of physics" in addition to the standard model ::)
OK, ready to change test setup a bit after much thought and planning.
Three words: Laser Displacement Sensor
Basically mount the sensor under the opposite end to NSF-1701 and measure displacement of end of balance beam. This is a non-contact, triangulation-based micrometer measuring system typically used to measure surface mount component height in pick and place assemblies.
The data rates are overkill for what we're trying to measure, but it could be translated into a nice chart or data set.
Now, here's the bad news...too expensive for a unique-use home budget. Best I ask for a loaner or donation, but am convinced this is the way to go; avoiding long throw lasers, mirrors and targets.
Which raises the question - if you're behind the Great Firewall of China, can you access NSF?
Or even (given the fact that Chinese are banned by NASA from visiting ISS) does NASA block China access to NSF?
I was able to access the Emdrive threads on NSF from Shanghai via cable modem connection during a 2 week stay with my in-laws. This was in June/July this year. Back to lurker mode for me.
Which raises the question - if you're behind the Great Firewall of China, can you access NSF?
Or even (given the fact that Chinese are banned by NASA from visiting ISS) does NASA block China access to NSF?
I was able to access the Emdrive threads on NSF from Shanghai via cable modem connection during a 2 week stay with my in-laws. This was in June/July this year. Back to lurker mode for me.
Welcome to the forum cbuchner1 . :)
That's a useful information, so Yang is also able to follow us, if she like.
But there is no answer from her till now and that's the bad news hidden in your post,
although some people try to get contact :-\
We are considering doing two experiments with an industrial magnetron transmitter (c/w waveguide launcher, isolator and waterload) and the University of Saskatoon; either a 100kW continuous into a copper frustrum 932Hz at TE012 (designing cooling system now..) or 5MW 10microsecond pulses. Looks like we would also try having the magnetron fire into the small base or the big base, maybe some with ports on the side. Have some ANSYS modelling going down now. We would also fire the unit towards the ground that buoyant effects are not in play (I don't know why anyone would aim to produce thrust in the up position right now since hot air rising / buoyant is probably the #1 explanation for positive tests). Objective would be to produce a non-null result an order of magnitude above background.
@rfmwguy: think like a bat, dude 8)Docs missing on lidar and ultrasonic not enough res...good thoughts tho. Triangulated laser modules are micrometer Res. Far more than I need, but am really itching to write some labview app. Can have it mark times, display motion and remotely turn on maggy. Get real ambitious and record temp, humidity, and video from cam. Labview is a workhorse on a laptop and most sensors are cheap.
http://hackaday.com/2014/01/23/lidar-with-leds-for-under-100/
http://www.miniinthebox.com/ultrasonic-sensor-hc-sr04-distance-measuring-module_p903315.html
Just two quick examples of the search space that will now consume your weekend ;D
Thought for today during coffee...
NSF1701 vents
Two points:
Rfmwguy's first data set shows signs of patterns in the output of a similar frequency to the cycling of the magnetron (at least to my eye). Fourier analysis on the de-trended signal (postulating a thermal ramp) might show correlation with the magnetron power cycling. If I had some kind of time series of nominal spot centre positions as numbers, I could give this a go. (This is one reason why cycling the power isn't always necessarily a bad thing).
I have to disagree with Dr. Rodal's conclusion that the likely effect is small, at least from one respect.
Rfmwguy's experiment hasn't yet changed our state of knowledge: Q is completely unknown, as is the mode shape, nor do we yet have any estimate of the actual thrust which has been stated in this thread. Both the numerator and denominator of thrust/power in the test are largely unknown. The effect may indeed be small, but rfmwguy's tests haven't yet affected the assessment of the size of the effect.
R.
...
There are also experiments that have already been done, that had null results but have not yet been properly documented in the EM Drive wiki for experimental results, for example: Mulletron's experiment who deserves to be recognized as the true leader in these Do-It-Yourself experiments, had null results documented in early threads, also the experiments with the experimenter that had constant cross-section waveguide and was using dielectric inserts, gave null results.
I understand that null results in these experiments don't close the book, as any experiment is limited on what can be tested (type of force measurement, set-up, etc.), but as Shell, says, "there is no bad data" and we should not forget those null results as well, as they are part of the big picture.
The big picture that is emerging is that if there is any EM Drive force (yes, it may be zero), its force/InputPower magnitude is of the very small magnitude reported by NASA (~0.001 Newton/KiloWatt) and by Dresden University (Tajmar) (0.00003 to 0.00013 Newton/KiloWatt) but not at all the thousands of times greater magnitudes reported by Shawyer (0.4 Newton/KiloWatt) and Yang (1 Newton/KiloWatt) - who nobody has been able to reproduce-
The force/InputPower reported by Iulian Berca was similar to the one reported by NASA.
...
Rfmwguy's experiment hasn't yet changed our state of knowledge: Q is completely unknown, as is the mode shape, nor do we yet have any estimate of the actual thrust which has been stated in this thread. Both the numerator and denominator of thrust/power in the test are largely unknown. The effect may indeed be small, but rfmwguy's tests haven't yet affected the assessment of the size of the effect.
R.
...
4) It is incorrect that <<denominator of thrust/power in the test are largely unknown>> the denominator: the InputPower is known. Most assuredly RFMWGUY did not conduct a test blindly without knowledge of the input power. Rfmwguy even conducted careful tests at different power settings and measured the temperatures, much prior to this actual test.
...
...
Rfmwguy's experiment hasn't yet changed our state of knowledge: Q is completely unknown, as is the mode shape, nor do we yet have any estimate of the actual thrust which has been stated in this thread. Both the numerator and denominator of thrust/power in the test are largely unknown. The effect may indeed be small, but rfmwguy's tests haven't yet affected the assessment of the size of the effect.
R.
...
4) It is incorrect that <<denominator of thrust/power in the test are largely unknown>> the denominator: the InputPower is known. Most assuredly RFMWGUY did not conduct a test blindly without knowledge of the input power. Rfmwguy even conducted careful tests at different power settings and measured the temperatures, much prior to this actual test.
...
Hi Dr. Rodal,
My interpretation of Rert's comments was that knowledge of raw magnetron InputPower is insufficient to define a denominator in the thrust/power equation. Unless I missed some critical information within this thread (quite possible), I don't think we know the impedance match between the magnetron and the frustum, and therefore don't know how much of the InputPower is actually getting coupled.
Do we currently have any way of determining reflected vs delivered power during rfmwguy's tests?
Admittedly I also don't know if reflected vs delivered power makes any difference in "thrust".... but given the Meep analysis so far being based upon delivered power to the frustum, I don't think I'm going to far out on a limb here with Rert. ;)
If I recall, TT has been nudging rfmwguy to insert a small antenna of some kind to at least allow for some crude S11 analysis and potential real-time monitoring with a cheap VNA during a power-on test. If rfmwguy could follow SeeShell's lead with a GoFundMe URL, maybe the collective NSF lurkers (such as myself) could help send some pocket change his way to help fund things like a cheap USB VNA. ;D
Thanks,
James
Ironically there is a unit set up to do 5MW pulses that can adjust frequency within 10MHz of 930MHz ( frustum dimensions would not have to be exact that we could find resonance). At 10 microseconds the cooling of the frustum is managable without online cooling. Issue is would you see something in 10microseconds? Such a test hopefully could produce results that are an order of magnitude above background (into the ground no buoyant effects) or allow other phenomena (photon thruster leakage?) to be measurable. This will probably be experiment one as it is relatively cheap. If it's CoM I expect to see something on a digital scale within those 10us.
I'm a RF microwave engineer who has been lurking here for a while.Thanks, I saw these but was uncertain if I could achieve 0.01 mm resolution at a distance of about 30 mm
I note RFguy found a laser displacement sensor that he feels is ideal for measuring DUT movement all but for the cost.
Has anybody considered using a capacitive displacement sensor? Analog Devices IIRC makes a capacity displacement ic sensor and Linear technology has published several capacitive displacement sensor circuits in there application notes, one IIRC authored by Jim Williams.
These will work in a vacuum if need be. The basic sensing technology is low power so ic heat management should be- well- manageable.
If anyone is interested in capacitive displacement sensing and unable to find useful information with google, you are welcome to contact me and I'll find the references I have in mind.
Every time you put food in a microwave, standing waves are made variable by either a rotating base or rotating deflector from the top. Mostly rotating base. The magnetron is fairly impervious to changes in standing waves, only when there are none does it overheat.
...
Rfmwguy's experiment hasn't yet changed our state of knowledge: Q is completely unknown, as is the mode shape, nor do we yet have any estimate of the actual thrust which has been stated in this thread. Both the numerator and denominator of thrust/power in the test are largely unknown. The effect may indeed be small, but rfmwguy's tests haven't yet affected the assessment of the size of the effect.
R.
...
4) It is incorrect that <<denominator of thrust/power in the test are largely unknown>> the denominator: the InputPower is known. Most assuredly RFMWGUY did not conduct a test blindly without knowledge of the input power. Rfmwguy even conducted careful tests at different power settings and measured the temperatures, much prior to this actual test.
...
Hi Dr. Rodal,
My interpretation of Rert's comments was that knowledge of raw magnetron InputPower is insufficient to define a denominator in the thrust/power equation. Unless I missed some critical information within this thread (quite possible), I don't think we know the impedance match between the magnetron and the frustum, and therefore don't know how much of the InputPower is actually getting coupled.
Do we currently have any way of determining reflected vs delivered power during rfmwguy's tests?
Admittedly I also don't know if reflected vs delivered power makes any difference in "thrust".... but given the Meep analysis so far being based upon delivered power to the frustum, I don't think I'm going to far out on a limb here with Rert. ;)
If I recall, TT has been nudging rfmwguy to insert a small antenna of some kind to at least allow for some crude S11 analysis and potential real-time monitoring with a cheap VNA during a power-on test. If rfmwguy could follow SeeShell's lead with a GoFundMe URL, maybe the collective NSF lurkers (such as myself) could help send some pocket change his way to help fund things like a cheap USB VNA. ;D
Thanks,
James
We don't have knowledge of "impedance match between the magnetron and the frustum" for most reported experiments, do we?.
Can you point out what numbers of force/InputPower reported in the EM Drive Wiki Experimental results have been calculated based on "impedance match between the magnetron and the frustum" and which ones have used the raw input power? ???
If the numerical force/InputPower reported in the EM Drive Wiki Experimental Results are calculated for the power consumed by the RF Feed, then what is good for the goose is also good for the gander :) . The raw input power should also be used for rfmwguy's experiment, just as it has been done for most other experiments.
Why should this impedance matching correction become all of a sudden a roadblock for calculation of this parameter for rfmwguy's experiment, when it was not a roadblock for other experiments? ???
For example, just to cite one example, I'm sure there was no "impedance matching correction" made for Iulian Berca's quoted numbers in the EM Drive wiki. The force/InputPower for Iulian Berca's experiment is based on the raw input power of 800 watts.
Why should "impedance matching correction" be all of a sudden necessary for rfmwguy's and not for Iulian Berca's experiment? ???
Two points:
Rfmwguy's first data set shows signs of patterns in the output of a similar frequency to the cycling of the magnetron (at least to my eye). Fourier analysis on the de-trended signal (postulating a thermal ramp) might show correlation with the magnetron power cycling. If I had some kind of time series of nominal spot centre positions as numbers, I could give this a go. (This is one reason why cycling the power isn't always necessarily a bad thing).
I have to disagree with Dr. Rodal's conclusion that the likely effect is small, at least from one respect.
Rfmwguy's experiment hasn't yet changed our state of knowledge: Q is completely unknown, as is the mode shape, nor do we yet have any estimate of the actual thrust which has been stated in this thread. Both the numerator and denominator of thrust/power in the test are largely unknown. The effect may indeed be small, but rfmwguy's tests haven't yet affected the assessment of the size of the effect.
R.
OK, I've concluded that something unusual occurred, not during the initial 5 minute, 30% cycle, but at the 1 minute, 100% cycle.That one was mine, and the same downward deflection that I had indicated. Attached is a higher framerate capture of that portion (~15fps).
Once the magnetron has warmed and settled in its "lifted" state, the 1 minute test began. Unlike in the other tests, there is approximately 15 seconds of downward frustum movement, as indicated by a rise in the laser trace in the pic below. The pic is the 1 minute complete test. Thanks to Croppa I believe, I clipped it and enhanced it in Gimp.
...
Whilst it may be unwise to do too much analysis of a video such as this, I'm doing it anyway ;D I was also intrigued by the pattern in the low power run of the first test. I used Fiji (imagej) TrackMate plugin to automatically track the centre of the spot. Here's a movie of how that looks (this is 60 fps so 15x realtime speed). The stepping during the 30% cycles seems quite clear. I'm attaching a file which contains the TrackMate data in case it's of use. Note that the Y position is increasing because the origin of the image is at the top left in ImageJ (also the Time value should be multiplied by 0.25).This is brilliant! I've done the same with the flight 2 data. Note the area of interest -- the more I look at it, the more it looks like a downward thrust signature...
Again, I realise there are multiple potential sources of error in this, but it's what we have right now. The improvements being planned by rfmwguy sound fantastic and tracking with high resolution should help to clear up what kind of effects we're really seeing and although the cycling on/off has some advantages, it muddies the waters somewhat since we have to guess what the magnetron's doing based on how it sounds. Having remotely triggered, full power runs with good spatial resolution would be perfect.
I finally finished the loop antenna modeling exercise. Not sure if this is still useful but I will post here. Likely the patterns are the most useful part - as they should give some idea of what modes can be stimulated.Simply beautiful! This was on my bucket list! Love it.
These models and results are made using a version of the NEC codes (specifically EZNEC). NEC antenna modeling is not perfect but if you stay within the constraints it can produce qualitatively useful results. As with all such models, quantitative results are highly dependent on many factors including geometry, signal quality, and many more. Hopefully these will be of use - particularly if the loops are in a spherical chicken in a vacuum.
I modeled three sizes of antenna 1/2, 1, and 2 wavelength circumference, at three different heights - 1/4, 1/2 and 1 wavelength. Also modeled each of these configurations for loops both parallel to and normal to their ground plane.
Sorry for how long this took - as some of you know I have been in the process of retiring and unfortunately this exercise mostly had to take place late in evening after all other boring but necessary stuff had been done. I am now free and hope to start detailed planning for my own DIY experiments soon.
Herman
I'm wanting to do a 1/10 loop to see what the patterns are.
The stickiness in rmfguy’s results have been bothering me. The thing remains stuck on the same spot from power off at 9:27 to the end of the video. The frustum is a big copper heatsink with decent airflow. It should cool quickly, except for the magnetron that has airflow issues. After making a couple math mistakes because it was late at night, I went and did up a spreadsheet for finding thermal lift from hot air in a cavity with dimensions in inches or centimeters.
Letting the computer do the thinking for me (and assuming that I didn’t make an error making it) and with an air temperature of around 160C I get:
(chamber size) (expected lift)
2 inch cube 60.62 mg
3 inch cube 204.59 mg
4 inch cube 484.96 mg
If rfmguy’s magnetron has a 4 inch cube for a heatsink, then the results are pretty much explained right there (throw in a little bit more thermal lift and you’re good to go).
What are the dimensions of the magnetron housing on NSF-1701?
Some new .csv files uploaded to Google drive. A few .png views also.Strange mode pattern. I think the reason for the interesting modes aero is the antenna's are in phase and that's not what happens inside of the cavity with the modes. In real testing the antennas would be 180 degrees out of phase by varying the coax lengths to each antenna. Even with loops (square loops are about the same patterns).
https://drive.google.com/folderview?id=0B1XizxEfB23tfmcxWjlORHBtazE5bW5zR0NHbXJzVU5QTHpHM1U1aXVoYzZkazRwUlpNaW8&usp=sharing (https://drive.google.com/folderview?id=0B1XizxEfB23tfmcxWjlORHBtazE5bW5zR0NHbXJzVU5QTHpHM1U1aXVoYzZkazRwUlpNaW8&usp=sharing)
This is SeeShell's Crazy Eddie model 2, revision 6. The revisions are the result of changing the antenna configuration. We were assured that this cavity geometry would resonate, and it does resonate very well. It was just surprisingly difficult to find an antenna configuration that excited a resonance mode. The mode that did finally excite is hard to identify, perhaps Dr. Rodal or other experts here will be able to nail it down. It was hoped that the cavity would resonate at 2.47 GHz, and the final calculated resonant frequency was 2.50 GHz, well within the 3% error bounds on Harminv.
Some of you may recall that back in April we did considerable work to nail down the errors in Harminv resonant frequency calculation. Dr. Dominic, who is an experienced meep user helped (did most of the work) to determine this. I, on the other hand, had forgotten about that effort until recently.
Two points:
Rfmwguy's first data set shows signs of patterns in the output of a similar frequency to the cycling of the magnetron (at least to my eye). Fourier analysis on the de-trended signal (postulating a thermal ramp) might show correlation with the magnetron power cycling. If I had some kind of time series of nominal spot centre positions as numbers, I could give this a go. (This is one reason why cycling the power isn't always necessarily a bad thing).
I have to disagree with Dr. Rodal's conclusion that the likely effect is small, at least from one respect.
Rfmwguy's experiment hasn't yet changed our state of knowledge: Q is completely unknown, as is the mode shape, nor do we yet have any estimate of the actual thrust which has been stated in this thread. Both the numerator and denominator of thrust/power in the test are largely unknown. The effect may indeed be small, but rfmwguy's tests haven't yet affected the assessment of the size of the effect.
R.
Whilst it may be unwise to do too much analysis of a video such as this, I'm doing it anyway ;D I was also intrigued by the pattern in the low power run of the first test. I used Fiji (imagej) TrackMate plugin to automatically track the centre of the spot. Here's a movie of how that looks (this is 60 fps so 15x realtime speed). The stepping during the 30% cycles seems quite clear. I'm attaching a file which contains the TrackMate data in case it's of use. Note that the Y position is increasing because the origin of the image is at the top left in ImageJ (also the Time value should be multiplied by 0.25).
Again, I realise there are multiple potential sources of error in this, but it's what we have right now. The improvements being planned by rfmwguy sound fantastic and tracking with high resolution should help to clear up what kind of effects we're really seeing and although the cycling on/off has some advantages, it muddies the waters somewhat since we have to guess what the magnetron's doing based on how it sounds. Having remotely triggered, full power runs with good spatial resolution would be perfect.
Two points:
Rfmwguy's first data set shows signs of patterns in the output of a similar frequency to the cycling of the magnetron (at least to my eye). Fourier analysis on the de-trended signal (postulating a thermal ramp) might show correlation with the magnetron power cycling. If I had some kind of time series of nominal spot centre positions as numbers, I could give this a go. (This is one reason why cycling the power isn't always necessarily a bad thing).
I have to disagree with Dr. Rodal's conclusion that the likely effect is small, at least from one respect.
Rfmwguy's experiment hasn't yet changed our state of knowledge: Q is completely unknown, as is the mode shape, nor do we yet have any estimate of the actual thrust which has been stated in this thread. Both the numerator and denominator of thrust/power in the test are largely unknown. The effect may indeed be small, but rfmwguy's tests haven't yet affected the assessment of the size of the effect.
R.
Whilst it may be unwise to do too much analysis of a video such as this, I'm doing it anyway ;D I was also intrigued by the pattern in the low power run of the first test. I used Fiji (imagej) TrackMate plugin to automatically track the centre of the spot. Here's a movie of how that looks (this is 60 fps so 15x realtime speed). The stepping during the 30% cycles seems quite clear. I'm attaching a file which contains the TrackMate data in case it's of use. Note that the Y position is increasing because the origin of the image is at the top left in ImageJ (also the Time value should be multiplied by 0.25).
Again, I realise there are multiple potential sources of error in this, but it's what we have right now. The improvements being planned by rfmwguy sound fantastic and tracking with high resolution should help to clear up what kind of effects we're really seeing and although the cycling on/off has some advantages, it muddies the waters somewhat since we have to guess what the magnetron's doing based on how it sounds. Having remotely triggered, full power runs with good spatial resolution would be perfect.
Some new .csv files uploaded to Google drive. A few .png views also.Strange mode pattern. I think the reason for the interesting modes aero is the antenna's are in phase and that's not what happens inside of the cavity with the modes. In real testing the antennas would be 180 degrees out of phase by varying the coax lengths to each antenna. Even with loops (square loops are about the same patterns).
https://drive.google.com/folderview?id=0B1XizxEfB23tfmcxWjlORHBtazE5bW5zR0NHbXJzVU5QTHpHM1U1aXVoYzZkazRwUlpNaW8&usp=sharing (https://drive.google.com/folderview?id=0B1XizxEfB23tfmcxWjlORHBtazE5bW5zR0NHbXJzVU5QTHpHM1U1aXVoYzZkazRwUlpNaW8&usp=sharing)
This is SeeShell's Crazy Eddie model 2, revision 6. The revisions are the result of changing the antenna configuration. We were assured that this cavity geometry would resonate, and it does resonate very well. It was just surprisingly difficult to find an antenna configuration that excited a resonance mode. The mode that did finally excite is hard to identify, perhaps Dr. Rodal or other experts here will be able to nail it down. It was hoped that the cavity would resonate at 2.47 GHz, and the final calculated resonant frequency was 2.50 GHz, well within the 3% error bounds on Harminv.
Some of you may recall that back in April we did considerable work to nail down the errors in Harminv resonant frequency calculation. Dr. Dominic, who is an experienced meep user helped (did most of the work) to determine this. I, on the other hand, had forgotten about that effort until recently.
Look at the attached png file and the profiles. They are in phase and being in phase they will not couple with the modes correctly.
This has been an issue with meep in how to reverse the phases on an antenna inside of the frustum. Open for ideas here on how to make meep flip phases.
Just use the amplitude property of the source, which is a complex number and can therefore set the phase:
(define gauss (make gaussian-src (frequency f) (fwidth df)))
(set! sources (list (make source (src gauss) (center 0))
(make source (src gauss) (center 0)
(amplitude (exp (* 0+1i phi))))))
Whilst it may be unwise to do too much analysis of a video such as this, I'm doing it anyway ;D I was also intrigued by the pattern in the low power run of the first test. I used Fiji (imagej) TrackMate plugin to automatically track the centre of the spot. Here's a movie of how that looks (this is 60 fps so 15x realtime speed). The stepping during the 30% cycles seems quite clear. I'm attaching a file which contains the TrackMate data in case it's of use. Note that the Y position is increasing because the origin of the image is at the top left in ImageJ (also the Time value should be multiplied by 0.25).This is brilliant! I've done the same with the flight 2 data. Note the area of interest -- the more I look at it, the more it looks like a downward thrust signature...
Again, I realise there are multiple potential sources of error in this, but it's what we have right now. The improvements being planned by rfmwguy sound fantastic and tracking with high resolution should help to clear up what kind of effects we're really seeing and although the cycling on/off has some advantages, it muddies the waters somewhat since we have to guess what the magnetron's doing based on how it sounds. Having remotely triggered, full power runs with good spatial resolution would be perfect.
The stickiness in rmfguy’s results have been bothering me. The thing remains stuck on the same spot from power off at 9:27 to the end of the video. The frustum is a big copper heatsink with decent airflow. It should cool quickly, except for the magnetron that has airflow issues. After making a couple math mistakes because it was late at night, I went and did up a spreadsheet for finding thermal lift from hot air in a cavity with dimensions in inches or centimeters.
Letting the computer do the thinking for me (and assuming that I didn’t make an error making it) and with an air temperature of around 160C I get:
(chamber size) (expected lift)
2 inch cube 60.62 mg
3 inch cube 204.59 mg
4 inch cube 484.96 mg
If rfmguy’s magnetron has a 4 inch cube for a heatsink, then the results are pretty much explained right there (throw in a little bit more thermal lift and you’re good to go).
What are the dimensions of the magnetron housing on NSF-1701?
my calculations don't quite agree with yours
My formula: Lift = V* (P/2.87)*((1/Tamb)-(1/Tenv))
Lift = kg
V = volume (m^3)
P = pressure (hPA)
Tamb = ambient temperature (K)
Tenv = envelope temperature (K)
assume sea level then P = 1013.25
assume ambient at 60 F = 288 K
assume envelope at 160 C = 433K
2 inch cube = .000065 cubic meters
3 inch cube = .000147 cubic meters
4 inch cube = .000262 cubic meters
Then unless I screwed up
2 inch lift = .027 mg
3 inch lift = .061 mg
4 inch lift = .107 mg
I'm sure we used different constants for ambient temp & pressure, but it looks like one of us is of by a factor of 1,000.
All this fantastic data analysis makes me yearn for Flight Test #3 8)I want reiterate that I don't think you need to do that. Definitely you should if you want, it's your experiment, but I think that just by moving the camera so the video is a close-up on the laser spot, we could get pretty high resolution, reliable data out of that.
I won't put you all through this again with low res video...I'm going to spring for a laser displacement sensor, amp and computer interface. Trying now to find the best price. It MAY require me to have a small crowdfund or gofund me page just for this equipment since I won't convince my wife that I could use the LDS for anything else around the house...c'mon, ya know how it is ;)
Two points:
Rfmwguy's first data set shows signs of patterns in the output of a similar frequency to the cycling of the magnetron (at least to my eye). Fourier analysis on the de-trended signal (postulating a thermal ramp) might show correlation with the magnetron power cycling. If I had some kind of time series of nominal spot centre positions as numbers, I could give this a go. (This is one reason why cycling the power isn't always necessarily a bad thing).
I have to disagree with Dr. Rodal's conclusion that the likely effect is small, at least from one respect.
Rfmwguy's experiment hasn't yet changed our state of knowledge: Q is completely unknown, as is the mode shape, nor do we yet have any estimate of the actual thrust which has been stated in this thread. Both the numerator and denominator of thrust/power in the test are largely unknown. The effect may indeed be small, but rfmwguy's tests haven't yet affected the assessment of the size of the effect.
R.
Whilst it may be unwise to do too much analysis of a video such as this, I'm doing it anyway ;D I was also intrigued by the pattern in the low power run of the first test. I used Fiji (imagej) TrackMate plugin to automatically track the centre of the spot. Here's a movie of how that looks (this is 60 fps so 15x realtime speed). The stepping during the 30% cycles seems quite clear. I'm attaching a file which contains the TrackMate data in case it's of use. Note that the Y position is increasing because the origin of the image is at the top left in ImageJ (also the Time value should be multiplied by 0.25).
Again, I realise there are multiple potential sources of error in this, but it's what we have right now. The improvements being planned by rfmwguy sound fantastic and tracking with high resolution should help to clear up what kind of effects we're really seeing and although the cycling on/off has some advantages, it muddies the waters somewhat since we have to guess what the magnetron's doing based on how it sounds. Having remotely triggered, full power runs with good spatial resolution would be perfect.
re: your stepping. I took a subsample of your data from your roughly 300 to 550 corresponding to your data points 1055 through 2291.
A linear fit gave me an R2 of .9885 which is pretty darn good. The base formula was y = 0.0381x + 50.887
Using my corresponding data points 1 through 1147, the residuals pretty much confirm your observation.
Attached image file
How about this!Yes! Nice work aero! Run it when you can.
First one - new, pi out of phase.
Second one - As it has been.
Works similiar to laser mouse. Maybe its cheaper to hack a mouse? :-\These things are pretty cool, they measure like a micrometer by bouncing a laser off a target and it reflects back at the sensor. I has more accuracy than I need, but talk about being able to see oscillations! I should be able to calibrate exact displacement for a variet of calibrated weights...no more guessing or estimating.
Btw congratz!
Works similiar to laser mouse. Maybe its cheaper to hack a mouse? :-\These things are pretty cool, they measure like a micrometer by bouncing a laser off a target and it reflects back at the sensor. I has more accuracy than I need, but talk about being able to see oscillations! I should be able to calibrate exact displacement for a variet of calibrated weights...no more guessing or estimating.
Btw congratz!
Not sure if any other experiments used something like this or not, but for vertical position changes, its the best I think.
Works similiar to laser mouse. Maybe its cheaper to hack a mouse? :-\These things are pretty cool, they measure like a micrometer by bouncing a laser off a target and it reflects back at the sensor. I has more accuracy than I need, but talk about being able to see oscillations! I should be able to calibrate exact displacement for a variet of calibrated weights...no more guessing or estimating.
Btw congratz!
Not sure if any other experiments used something like this or not, but for vertical position changes, its the best I think.
My I suggest that you run at 50% - 80% power on the MW, for about 10 - 20 minutes, continuously. Because,
1. This will give plenty of time for the air to heat up and the rig to stabilize at a relatively constant air temperature.
2. The cycling will then allow us to tell if there is thrust when it is on and none when it is off, that is not due to hot air.
Contrary to what others have said, I think that given this buoyancy effect we're seeing, having it run continuously at 100% won't show us thrust, because there is no stable baseline to compare it to. Allowing it to cycle on and off AFTER the temperatures have stabilized, will allow us to measure the difference and thereby, the thrust. The data thus far shows that the temperature drift will stabilize after a time.
Todd
Re-uploaded the dual big end stub antenna run for the Crazy-Eddie, Rev. 2 model. During this run, the antennas were 180 degrees out of phase. All else is the same. However, the Harminv calculated resonant frequency was lower, by about 40 kHz, and the calculated quality factor was an order of magnitude less but still an unrealistic 200,000. That tells us that this configuration will resonate, but no more than that. Still, that's good to know.
https://drive.google.com/folderview?id=0B1XizxEfB23tfmcxRU96aGNHWkdPSHM5MmlxNi00NUtkZFdMVllkOU9oV3R6SG55Y2p5Zlk&usp=sharing (https://drive.google.com/folderview?id=0B1XizxEfB23tfmcxRU96aGNHWkdPSHM5MmlxNi00NUtkZFdMVllkOU9oV3R6SG55Y2p5Zlk&usp=sharing)
There are png view files of slice 13 (30 views) along with the Python plot program used to generate them. If there is an expert in plotting with this program, it would be nice if you could take the time needed to provide a different color map. In fact, I think all would prefer contour lines with magnitude labels. Colors are not so important except some colors burn out the eyeball and should be avoided. The plot program is available for download, and more information about it, as well as the original source is available on the emdrive wiki. Thanks.
There's something very, very wrong there, as should be obvious.You talking to me? If so, spill it, maybe we agree.
Get ready...am now running NSF-1701 Flight Test 2A
This will be long duration recording of about 30 minutes beginning with a 5 minute duration of 30% power cycle. Reason its 2A is no changes made to engine, only laser target. Vid is closeup of target only. Seems much higher resolution. Overall duration is to monitor lift to see how it settles back after end of power cycle. A 500 mg calibrated weight was added then removed prior to powerup.
Get ready...am now running NSF-1701 Flight Test 2A
This will be long duration recording of about 30 minutes beginning with a 5 minute duration of 30% power cycle. Reason its 2A is no changes made to engine, only laser target. Vid is closeup of target only. Seems much higher resolution. Overall duration is to monitor lift to see how it settles back after end of power cycle. A 500 mg calibrated weight was added then removed prior to powerup.
I'm talking about the software that calculates ridiculously high Q values.There's something very, very wrong there, as should be obvious.You talking to me? If so, spill it, maybe we agree.
Reading Tom Clancy's "Support and Defend." But I find pot shots in the dark annoying in the best of times.I'm talking about the software that calculates ridiculously high Q values.There's something very, very wrong there, as should be obvious.You talking to me? If so, spill it, maybe we agree.
And either dial down the aggression, or get some fresh air and walk it off.
Too many gangster movies?
I just finished watching Salt. I regret that you were annoyed. Obviously you identify pretty closely with the code. At least you've shown that the Q value spat out is of qualitative use, even though the absolute value is useless. That's worth knowing.Reading Tom Clancy's "Support and Defend." But I find pot shots in the dark annoying in the best of times.I'm talking about the software that calculates ridiculously high Q values.There's something very, very wrong there, as should be obvious.You talking to me? If so, spill it, maybe we agree.
And either dial down the aggression, or get some fresh air and walk it off.
Too many gangster movies?
As for the meat of your comment, the calculated Q values are not very useful as numeric values. I have found though that ridiculously high Q values result in calculated field evolution that clearly leads to resonance while very low to no Q values result in calculated fields that really never evolve to anything discernible. As far as I can tell that is the utility of the calculated Q from this program.
Perhaps you can tell me this - Can these cavity field patterns be considered as Bloch Periodic? I ask because I have MPB installed but have never used it. It is applicable to problems that satisfy Bloch's Theorem.
MPB, also developed at MIT, can be thought of as a sister program to meep, it calculates frequencies and modes using Fourier transforms. I speculate that many meep users avoid Harminv and use MPB instead but have no basis to say that.
I just finished watching Salt. I regret that you were annoyed. Obviously you identify pretty closely with the code. At least you've shown that the Q value spat out is of qualitative use, even though the absolute value is useless. That's worth knowing.Reading Tom Clancy's "Support and Defend." But I find pot shots in the dark annoying in the best of times.I'm talking about the software that calculates ridiculously high Q values.There's something very, very wrong there, as should be obvious.You talking to me? If so, spill it, maybe we agree.
And either dial down the aggression, or get some fresh air and walk it off.
Too many gangster movies?
As for the meat of your comment, the calculated Q values are not very useful as numeric values. I have found though that ridiculously high Q values result in calculated field evolution that clearly leads to resonance while very low to no Q values result in calculated fields that really never evolve to anything discernible. As far as I can tell that is the utility of the calculated Q from this program.
Perhaps you can tell me this - Can these cavity field patterns be considered as Bloch Periodic? I ask because I have MPB installed but have never used it. It is applicable to problems that satisfy Bloch's Theorem.
MPB, also developed at MIT, can be thought of as a sister program to meep, it calculates frequencies and modes using Fourier transforms. I speculate that many meep users avoid Harminv and use MPB instead but have no basis to say that.
Many years ago I did a degree which included solid state physics and I recall Bloch. But since I haven't used it since, I've forgotten about it. I'm not your man for that.
(harminv-Q result)
Return dimensionless lifetime, or "quality factor", Q, defined as -\mathrm{Re}\,\omega / 2 \mathrm{Im}\,\omega.
(that is, -Re(w) / 2 Im(w), the negative of the real part of the complex frequency divided by twice the imaginary part)
NSF-1701 FT #2A Video
https://youtu.be/Oq44P8b87L8
Re-uploaded the dual big end stub antenna run for the Crazy-Eddie, Rev. 2 model. During this run, the antennas were 180 degrees out of phase. All else is the same. However, the Harminv calculated resonant frequency was lower, by about 40 kHz, and the calculated quality factor was an order of magnitude less but still an unrealistic 200,000. That tells us that this configuration will resonate, but no more than that. Still, that's good to know.
https://drive.google.com/folderview?id=0B1XizxEfB23tfmcxRU96aGNHWkdPSHM5MmlxNi00NUtkZFdMVllkOU9oV3R6SG55Y2p5Zlk&usp=sharing (https://drive.google.com/folderview?id=0B1XizxEfB23tfmcxRU96aGNHWkdPSHM5MmlxNi00NUtkZFdMVllkOU9oV3R6SG55Y2p5Zlk&usp=sharing)
There are png view files of slice 13 (30 views) along with the Python plot program used to generate them. If there is an expert in plotting with this program, it would be nice if you could take the time needed to provide a different color map. In fact, I think all would prefer contour lines with magnitude labels. Colors are not so important except some colors burn out the eyeball and should be avoided. The plot program is available for download, and more information about it, as well as the original source is available on the emdrive wiki. Thanks.
Does anyone know if Eagleworks is continuing to work on EMDrive? If so did they say when news can be expected?
Shells idea isnt bad but some parts of the magnetic vector fields around the dipoles are not equal to the field of the TE01 mode. Caused by that the excited field will be degenerated/ deformed.Re-uploaded the dual big end stub antenna run for the Crazy-Eddie, Rev. 2 model. During this run, the antennas were 180 degrees out of phase. All else is the same. However, the Harminv calculated resonant frequency was lower, by about 40 kHz, and the calculated quality factor was an order of magnitude less but still an unrealistic 200,000. That tells us that this configuration will resonate, but no more than that. Still, that's good to know.
https://drive.google.com/folderview?id=0B1XizxEfB23tfmcxRU96aGNHWkdPSHM5MmlxNi00NUtkZFdMVllkOU9oV3R6SG55Y2p5Zlk&usp=sharing (https://drive.google.com/folderview?id=0B1XizxEfB23tfmcxRU96aGNHWkdPSHM5MmlxNi00NUtkZFdMVllkOU9oV3R6SG55Y2p5Zlk&usp=sharing)
There are png view files of slice 13 (30 views) along with the Python plot program used to generate them. If there is an expert in plotting with this program, it would be nice if you could take the time needed to provide a different color map. In fact, I think all would prefer contour lines with magnitude labels. Colors are not so important except some colors burn out the eyeball and should be avoided. The plot program is available for download, and more information about it, as well as the original source is available on the emdrive wiki. Thanks.
Your first image below showed two dipole antennas 180° out-of-phase and located near the big base and in the middle of the predicted "lower lobes" of TE012 mode. That's a good placement IMHO.
However what we see in the following pictures is the two antennas are stuck on the side walls, like for regular 1/4 λ stub antennas:
https://drive.google.com/file/d/0B1XizxEfB23tUHJOeFpTZkRUc1k/view
https://drive.google.com/file/d/0B1XizxEfB23tWDBTTXpWMkVLOTA/view
https://drive.google.com/file/d/0B1XizxEfB23tQThhUmkzck9xZGM/view
https://drive.google.com/file/d/0B1XizxEfB23tdXZHUTMyekx4eWs/view
https://drive.google.com/file/d/0B1XizxEfB23tWVJLNmI4NzNPQlE/view
So maybe it is the location of the antennas that is not correct. Shouldn't they be located more near the center of axi-symmetry of the cavity, like in the picture below?
I just finished watching Salt. I regret that you were annoyed. Obviously you identify pretty closely with the code. At least you've shown that the Q value spat out is of qualitative use, even though the absolute value is useless. That's worth knowing.Reading Tom Clancy's "Support and Defend." But I find pot shots in the dark annoying in the best of times.I'm talking about the software that calculates ridiculously high Q values.There's something very, very wrong there, as should be obvious.You talking to me? If so, spill it, maybe we agree.
And either dial down the aggression, or get some fresh air and walk it off.
Too many gangster movies?
As for the meat of your comment, the calculated Q values are not very useful as numeric values. I have found though that ridiculously high Q values result in calculated field evolution that clearly leads to resonance while very low to no Q values result in calculated fields that really never evolve to anything discernible. As far as I can tell that is the utility of the calculated Q from this program.
Perhaps you can tell me this - Can these cavity field patterns be considered as Bloch Periodic? I ask because I have MPB installed but have never used it. It is applicable to problems that satisfy Bloch's Theorem.
MPB, also developed at MIT, can be thought of as a sister program to meep, it calculates frequencies and modes using Fourier transforms. I speculate that many meep users avoid Harminv and use MPB instead but have no basis to say that.
Many years ago I did a degree which included solid state physics and I recall Bloch. But since I haven't used it since, I've forgotten about it. I'm not your man for that.
Here is the Harminv definition: Does it make sense to you?Quote(harminv-Q result)
Return dimensionless lifetime, or "quality factor", Q, defined as -\mathrm{Re}\,\omega / 2 \mathrm{Im}\,\omega.
(that is, -Re(w) / 2 Im(w), the negative of the real part of the complex frequency divided by twice the imaginary part)
As I understand things, the frequency should be real so the imaginary part should be tiny and so Q should be huge?
With MEEP this particular ring resonator has Q ~ 10^7 however with BCALM I am not able to reach 10^5.
Okay, here's the TrackMate analysis on NSF-1701 #2A.
My interpretation is that this confirms that your knife-edge balance is sticking (see the lack of recovery from when the weight was added, to after it was taken off.
I've included two images:
-One with the full data plot - this would be the one to look at for thrust signatures during the run. To my eye there appears to be either none, or else possibly a downward thrust at the very beginning of the run (it is hard to tell due to lengthy laser obstruction immediately prior to the run)
-Another where I've shrunk the x-axis from the time when the microwave is started until the end - this one makes it easier to see what we're identifying as the thermal lift, and the subsequent recovery. It does appear to go back down after the run is completed, even below its original height
My take on this run as a whole is that it seems to indicate that the knife-edge fulcrum might be a problem, especially in long-term height drift measurement.
However, that doesn't necessarily imply that it's not still useful for short-term thrust measurement.
[Edit] I'm now also attaching the raw data that goes with that plot (whitespace separated values).
rfmwguyThe blue in the vid is a reflection of the android screen on the laser paper. There is probably something on the screen moving about as its recording. I'll try to fix that next time...
You are best person to ask, look from about 15:00 -15:50
there is what appears to be a blue light in background moving up and down a bit
doesn't seem that noticeable elsewhere.
What is it do you think it is?
Where is it coming from?
and thankyou for posting -it's quite fun...
Does this confirm that the pivot is sticky? - it looks that way.I think there is abit, DM. Will take me a while to look at the data, but it does seem its not recentering. Still useful for testing for magnetron thrust, but not an ideal balance. Off to a company golf outing...
@aero: The harminv thing makes no sense to me.
I just finished watching Salt. I regret that you were annoyed. Obviously you identify pretty closely with the code. At least you've shown that the Q value spat out is of qualitative use, even though the absolute value is useless. That's worth knowing.Reading Tom Clancy's "Support and Defend." But I find pot shots in the dark annoying in the best of times.I'm talking about the software that calculates ridiculously high Q values.There's something very, very wrong there, as should be obvious.You talking to me? If so, spill it, maybe we agree.
And either dial down the aggression, or get some fresh air and walk it off.
Too many gangster movies?
As for the meat of your comment, the calculated Q values are not very useful as numeric values. I have found though that ridiculously high Q values result in calculated field evolution that clearly leads to resonance while very low to no Q values result in calculated fields that really never evolve to anything discernible. As far as I can tell that is the utility of the calculated Q from this program.
Perhaps you can tell me this - Can these cavity field patterns be considered as Bloch Periodic? I ask because I have MPB installed but have never used it. It is applicable to problems that satisfy Bloch's Theorem.
MPB, also developed at MIT, can be thought of as a sister program to meep, it calculates frequencies and modes using Fourier transforms. I speculate that many meep users avoid Harminv and use MPB instead but have no basis to say that.
Many years ago I did a degree which included solid state physics and I recall Bloch. But since I haven't used it since, I've forgotten about it. I'm not your man for that.
Here is the Harminv definition: Does it make sense to you?Quote(harminv-Q result)
Return dimensionless lifetime, or "quality factor", Q, defined as -\mathrm{Re}\,\omega / 2 \mathrm{Im}\,\omega.
(that is, -Re(w) / 2 Im(w), the negative of the real part of the complex frequency divided by twice the imaginary part)
As I understand things, the frequency should be real so the imaginary part should be tiny and so Q should be huge?
1) The equation in Meep to calculate Q is correct. However, any equation is subject to the principle of "GIGO"= Garbage In = Garbage Out. No correct equation can give a correct solution when incorrect material constants are used.
2) The Q you calculate is too large because the Drude constant values used are equivalent to having too small power losses. In other words, the Drude constant values you use are an incorrect model of physical reality. Are you using the Drude constants suggested by deltaMass ??? We had discussed in the past changing the Drude constants and conducting Meep runs to see the change in Q with Drude constant values.
3) Take a look at http://sourceforge.net/p/b-calm/discussion/1746892/thread/913537ab/, where a user tells another user that eps averaging in Meep was responsible for Meep giving Q values orders of magnitude larger than the Q calculated by Belgium California Light Machine (B-CALM, a 3D GPU-based Finite-Difference Time-Domain program for electromagnetic problems):QuoteWith MEEP this particular ring resonator has Q ~ 10^7 however with BCALM I am not able to reach 10^5.
The Meep user finally admitted that by turning eps averaging off the Q value calculated by Meep came down to only 3 times the Q value calculated by B-CALM.
...On the other side with the meep analysis of the frustum I've come to the conclusion that without modeling the loop or square antenna any layouts will be lacking on exciting the TE mode....I agree, I've come to the same conclusion that without modeling the loop antenna you will not be properly exciting an axi-symmetric TE mode. (See emphasis on "axi-symmetric")
One more, with areas of interest for this flight.Kwertyops, very impressed with your work...thank you. Stickiness is there making it an imperfect balance but useable for short term changes as you said. I can also reset balance points to unused portions of blades which I did not do in ft2a. I'm afraid the oscillations at start of run are my keypad inputs on microwave. It is electromechanicly connected to nsf-1701 through galinstan, but this is high viscosity and think it transmits small vibrations like a solid coupling. I've got to remote the power on signal and will try and do that over the next several days. Small improvements bit by bit thanks to your analysis.
...On the other side with the meep analysis of the frustum I've come to the conclusion that without modeling the loop or square antenna any layouts will be lacking on exciting the TE mode....I agree, I've come to the same conclusion that without modeling the loop antenna you will not be properly exciting an axi-symmetric TE mode. (See emphasis on "axi-symmetric")
Still, this shows that Meep has been very useful in showing how important is the antenna's shape and its location Even when Meep excited a TE mode with a parallel dipole (for the Yang/Shell 6 degree cone angle geometry) , the mode shapes were not axi-symmetric. The only way that appears possible to excite an axi-symmetric TE mode is with a loop antenna. A square antenna will not do, I think, because the square shape is incompatible with circumferential axi-symmetry.
Even when Meep excites a TM mode with a dipole, the mode shape is not axi-symmetric either. The antenna really distorts the mode shape into two perpendicular axes: parallel to the dipole and perpendicular to the dipole.
The other thing we have learnt from Meep(post processed with Wolfram Mathematica) is that the EM Drive cannot be modeled solely with standing waves (as done for example by Greg Egan, as an eigenvalue problem, ignoring the effect of the RF feed). It is crucial to model the RF feed: it changes the conditions inside the cavity, particularly the stresses at the big base
Good idea :)...On the other side with the meep analysis of the frustum I've come to the conclusion that without modeling the loop or square antenna any layouts will be lacking on exciting the TE mode....I agree, I've come to the same conclusion that without modeling the loop antenna you will not be properly exciting an axi-symmetric TE mode. (See emphasis on "axi-symmetric")
Still, this shows that Meep has been very useful in showing how important is the antenna's shape and its location Even when Meep excited a TE mode with a parallel dipole (for the Yang/Shell 6 degree cone angle geometry) , the mode shapes were not axi-symmetric. The only way that appears possible to excite an axi-symmetric TE mode is with a loop antenna. A square antenna will not do, I think, because the square shape is incompatible with circumferential axi-symmetry.
Even when Meep excites a TM mode with a dipole, the mode shape is not axi-symmetric either. The antenna really distorts the mode shape into two perpendicular axes: parallel to the dipole and perpendicular to the dipole.
The other thing we have learnt from Meep(post processed with Wolfram Mathematica) is that the EM Drive cannot be modeled solely with standing waves (as done for example by Greg Egan, as an eigenvalue problem, ignoring the effect of the RF feed). It is crucial to model the RF feed: it changes the conditions inside the cavity, particularly the stresses at the big base
Absolutely!
I couldn't agree more. This is also the case with injecting the magnetron directly into the cavity whether it's with a Z-matched hole in the top or bottom or sidewall injection, axisymmetrically injections is the key for the correct mode generation. Only then the cones asymmetrical shape will lead to the highest stress generation on the plates and walls.
I believe some at EW understood this just from looking at some of the layouts and I wish they could comment but sadly they can not.
Loop or square. I was thinking if areo could model a very short cylinder why couldn't he model one inside the frustum with a small section cut away where the feeds are? I'm probably over simplifying it and it is a tough nut to crack.
Shell
...I fully agree, a large number (say every 10 degrees: 36 such antennas) of short antennas around the circumference, would ensure axi-symmetry .
Good idea :)
Another way may be the useage a larger number of dipoles to form a loop like antenna structure?
From what I've heard and been PMed by an old friend (retired high energy physics). You can generate a stable mode in a frustum, not easy, but doable and this is what I'm looking for!...I fully agree, a large number (say every 10 degrees: 36 such antennas) of short antennas around the circumference, would ensure axi-symmetry .
Good idea :)
Another way may be the useage a larger number of dipoles to form a loop like antenna structure?
Please, no long dipole antennas: long antennas distort the symmetry of the modes !
...I fully agree, a large number (say every 10 degrees: 36 such antennas) of short antennas around the circumference, would ensure axi-symmetry .
Good idea :)
Another way may be the useage a larger number of dipoles to form a loop like antenna structure?
Please, no long dipole antennas: long antennas distort the symmetry of the modes !
...I fully agree, a large number (say every 10 degrees: 36 such antennas) of short antennas around the circumference, would ensure axi-symmetry .
Good idea :)
Another way may be the useage a larger number of dipoles to form a loop like antenna structure?
Please, no long dipole antennas: long antennas distort the symmetry of the modes !
I can probably do something like that but I sure wish there were another meeper who would make and run some models of their own. Someone working the same problem to compare notes with.
As for artificially changing the Drude model so that the calculated Q value is realistic, I don't know. Could probably do it but I believe it would need to be done on a case by case basis. I don't think I would find a "One size fits all" solution. And I am reluctant to add the series of runs required for realistic Q to every change in the model. As all can see, calculated Q changes by changing the antenna and it also changes for the same cavity, same antenna but different EM field component excitation. The current model, CE2 - 8 gives a Q ranging from nothing to 47 million depending on which of the six field components is used to excite the antennas. I'm pretty sure that adding resistance to the copper without a sound theoretical basis would be a lost cause. The current model does have a sound theoretical basis at least. There may be something missing (no idea what) but what is there is soundly based.
...I fully agree, a large number (say every 10 degrees: 36 such antennas) of short antennas around the circumference, would ensure axi-symmetry .
Good idea :)
Another way may be the useage a larger number of dipoles to form a loop like antenna structure?
Please, no long dipole antennas: long antennas distort the symmetry of the modes !
I can probably do something like that but I sure wish there were another meeper who would make and run some models of their own. Someone working the same problem to compare notes with.
As for artificially changing the Drude model so that the calculated Q value is realistic, I don't know. Could probably do it but I believe it would need to be done on a case by case basis. I don't think I would find a "One size fits all" solution. And I am reluctant to add the series of runs required for realistic Q to every change in the model. As all can see, calculated Q changes by changing the antenna and it also changes for the same cavity, same antenna but different EM field component excitation. The current model, CE2 - 8 gives a Q ranging from nothing to 47 million depending on which of the six field components is used to excite the antennas. I'm pretty sure that adding resistance to the copper without a sound theoretical basis would be a lost cause. The current model does have a sound theoretical basis at least. There may be something missing (no idea what) but what is there is soundly based.
...I fully agree, a large number (say every 10 degrees: 36 such antennas) of short antennas around the circumference, would ensure axi-symmetry .
Good idea :)
Another way may be the useage a larger number of dipoles to form a loop like antenna structure?
Please, no long dipole antennas: long antennas distort the symmetry of the modes !
I can probably do something like that but I sure wish there were another meeper who would make and run some models of their own. Someone working the same problem to compare notes with.
As for artificially changing the Drude model so that the calculated Q value is realistic, I don't know. Could probably do it but I believe it would need to be done on a case by case basis. I don't think I would find a "One size fits all" solution. And I am reluctant to add the series of runs required for realistic Q to every change in the model. As all can see, calculated Q changes by changing the antenna and it also changes for the same cavity, same antenna but different EM field component excitation. The current model, CE2 - 8 gives a Q ranging from nothing to 47 million depending on which of the six field components is used to excite the antennas. I'm pretty sure that adding resistance to the copper without a sound theoretical basis would be a lost cause. The current model does have a sound theoretical basis at least. There may be something missing (no idea what) but what is there is soundly based.
In for another cuppa coffee.
Question, how does the meep software calculate the Q? it it a one simulated pulse into the cavity or does it look at a set series. The reason is if we are collapsing a mode every full wavelength and regaining it in the next. How can you get any Q from the decaying modes so frequently? Can it be specified the number of pulses meep uses in calculating the Q?
Back out.
Shell
given a discrete-time, finite-length signal that consists of a sum of finitely-many sinusoids (possibly exponentially decaying) in a given bandwidth, it determines the frequencies, decay constants, amplitudes, and phases of those sinusoids.
...I fully agree, a large number (say every 10 degrees: 36 such antennas) of short antennas around the circumference, would ensure axi-symmetry .
Good idea :)
Another way may be the useage a larger number of dipoles to form a loop like antenna structure?
Please, no long dipole antennas: long antennas distort the symmetry of the modes !
I can probably do something like that but I sure wish there were another meeper who would make and run some models of their own. Someone working the same problem to compare notes with.
As for artificially changing the Drude model so that the calculated Q value is realistic, I don't know. Could probably do it but I believe it would need to be done on a case by case basis. I don't think I would find a "One size fits all" solution. And I am reluctant to add the series of runs required for realistic Q to every change in the model. As all can see, calculated Q changes by changing the antenna and it also changes for the same cavity, same antenna but different EM field component excitation. The current model, CE2 - 8 gives a Q ranging from nothing to 47 million depending on which of the six field components is used to excite the antennas. I'm pretty sure that adding resistance to the copper without a sound theoretical basis would be a lost cause. The current model does have a sound theoretical basis at least. There may be something missing (no idea what) but what is there is soundly based.
In for another cuppa coffee.
Question, how does the meep software calculate the Q? it it a one simulated pulse into the cavity or does it look at a set series. The reason is if we are collapsing a mode every full wavelength and regaining it in the next. How can you get any Q from the decaying modes so frequently? Can it be specified the number of pulses meep uses in calculating the Q?
Back out.
Shell
One more, with areas of interest for this flight.Kwertyops, very impressed with your work...thank you. Stickiness is there making it an imperfect balance but useable for short term changes as you said. I can also reset balance points to unused portions of blades which I did not do in ft2a. I'm afraid the oscillations at start of run are my keypad inputs on microwave. It is electromechanicly connected to nsf-1701 through galinstan, but this is high viscosity and think it transmits small vibrations like a solid coupling. I've got to remote the power on signal and will try and do that over the next several days. Small improvements bit by bit thanks to your analysis.
Is the green portion of the test results showing the truncated cone moving in the direction of the small base (when the magnetron is on) much larger and significant than in previous test runs?
(http://forum.nasaspaceflight.com/xindex.php,qaction=dlattach,3Btopic=38203.0,3Battach=1062044,3Bimage.pagespeed.ic.Eb_5Iaovfl.jpg)
(http://forum.nasaspaceflight.com/xindex.php,qaction=dlattach,3Btopic=38203.0,3Battach=1062673,3Bimage.pagespeed.ic.NDiZfQivy0.jpg)
This is the first run for NSF-1701 where I see a very clear movement in the direction of the small base
If so, can you point out to what changes in this latest run may have been responsible (in your view) for the very noticeable movement toward the small base?
I have not seen any basis to justify the Drude constants to be realisitc for microwave frequencies.
I have a suggestion for the model....I fully agree, a large number (say every 10 degrees: 36 such antennas) of short antennas around the circumference, would ensure axi-symmetry .
Good idea :)
Another way may be the useage a larger number of dipoles to form a loop like antenna structure?
Please, no straight long dipole antennas: straight long antennas distort the symmetry of the modes !
An important issue is that Harminv (the harmonic inversion software for Meep) is being used to examine the response so far when the response is growing exponentially during the transient with the RF Feed on.QuoteI have not seen any basis to justify the Drude constants to be realisitc for microwave frequencies.
@Deltamass - Do you want to respond to Dr. Rodal? As I recall you did devote significant effort to develop the Drude model and did use the correct range of microwave frequency in your derivation.
I have a suggestion for the model....I fully agree, a large number (say every 10 degrees: 36 such antennas) of short antennas around the circumference, would ensure axi-symmetry .
Good idea :)
Another way may be the useage a larger number of dipoles to form a loop like antenna structure?
Please, no straight long dipole antennas: straight long antennas distort the symmetry of the modes !
Cone dimensions (CrazyEddie).
Dipole orientation like in the picture(YangShell), but more and shorter antennas around the circumference near the big end.
Note that the YangShell design with only two dipoles in this configuration showed TE01 but deformed.
NSF-1701 Flight Test 2A laser position graph posted on Reddit (https://www.reddit.com/r/EmDrive/comments/3iy440/nsf1701_flight_test_2a_laser_position_graph/) by @EmDriven.
@kwertyops: did you flip your graphs upside-down in order to show a downwards thrust of the frustum going with the curve going also downwards? I'm talking of your graphs in this post (http://forum.nasaspaceflight.com/index.php?topic=38203.msg1421125#msg1421125).
can you upload the full trackmate data file plese, this just has displacement.
Also
Can you upload the video that's generated? I suspect that the change in the target made spotify splot.
...Rodal, as I said the two graphs are identical but one of them has been flipped upside-down, see the drawing below where I put them together on the same scale.Thank you so much for kindly taking the time to explain this so clearly and thoroughly.
The small base in NSF-1701 Flight Test 2A points towards the floor, downwards. When the frustum goes upwards (a priori due to thermal effects) the laser dot goes downwards.
EmDriven (blue/brown curve) on Reddit claims he showed the weight, whereas kwertyops (red) shows laser position (?)
kwertyops's curve increases while EmDriven's brown portion of his blue curve decreases. There is something I don't understand in those curves: to me it a appears a weight reduction (EmDriven) should follow laser position (kwertyops) in the same trend, because both would track a frustum going upwards. But they are opposite. Why?
For now in my opinion there is no thrust signature in NSF-1701 Flight Test 2A graphs, only vibration and thermal artifacts.
Sad to say I threw away the papers containing that work.QuoteI have not seen any basis to justify the Drude constants to be realisitc for microwave frequencies.
@Deltamass - Do you want to respond to Dr. Rodal? As I recall you did devote significant effort to develop the Drude model and did use the correct range of microwave frequency in your derivation.
Meep turns the RF feed off based on its internal calculations, not user specified.An important issue is that Harminv (the harmonic inversion software for Meep) is being used to examine the response so far when the response is growing exponentially during the transient with the RF Feed on.QuoteI have not seen any basis to justify the Drude constants to be realisitc for microwave frequencies.
@Deltamass - Do you want to respond to Dr. Rodal? As I recall you did devote significant effort to develop the Drude model and did use the correct range of microwave frequency in your derivation.
The correct way to calculate Q (as we discussed before) should be:
1) Run Meep with an RF feed ON, for a geometry and RF feed where the Meep model excites the same mode that is excited at the natural frequency in an eigenvalue problem (with standing waves, no RF feed).
2) Turn the RF feed OFF in Meep after a reasonably amount of time has elapsed (from prior calculations, it looks like 128 cycles would be OK, as by that time the amplitude is close to being stable, as the exponential growth has decreased significantly)
3) Use Harminv to harmonically invert the frequency response with the RF feed OFF, and determine the Q for the RF feed off.That is exactly what is done -
The present analysis for Q are being done with the RF feed on, and therefore do not represent a clean decay of the response, since with the RF feed ON one has an exponentially growing response instead of a decaying response.No, that is not correct. Harminv does not start until a user specified time (* gc T_meep) after sources are turned off.
...Rodal, as I said the two graphs are identical but one of them has been flipped upside-down, see the drawing below where I put them together on the same scale.Thank you so much for kindly taking the time to explain this so clearly and thoroughly.
The small base in NSF-1701 Flight Test 2A points towards the floor, downwards. When the frustum goes upwards (a priori due to thermal effects) the laser dot goes downwards.
EmDriven (blue/brown curve) on Reddit claims he showed the weight, whereas kwertyops (red) shows laser position (?)
kwertyops's curve increases while EmDriven's brown portion of his blue curve decreases. There is something I don't understand in those curves: to me it a appears a weight reduction (EmDriven) should follow laser position (kwertyops) in the same trend, because both would track a frustum going upwards. But they are opposite. Why?
For now in my opinion there is no thrust signature in NSF-1701 Flight Test 2A graphs, only vibration and thermal artifacts.
..
No, that is not correct. Harminv does not start until a user specified time (* gc T_meep) after sources are turned off.
We are probably overlooking the elephant in the room. That is resolution. The resistance of the copper cavity only effects the model within the skin depth of the copper, a few micrometers. The grid spacing is on the order of millimetres (1.2 mm) so meep has no way to detect an effect from that resistance.
At resolution of 250 the number of computational cells is 12,323,175 for the CE2 model At about 10 words of data storage per data cell gives - call it 125 MB of memory required. Double the resolution to 500 gives grid spacing of about 0.6 mm and requires about 1 GB of computer memory. Double it again and at 8 GB the problem is well beyond my machine but the grid spacing is only down to 300 micrometers.
Increasing resolution with a realistic copper model is not the solution so we need a copper model that simulates the real effect at much lower resolution. I model cone wall and end thickness as 1/4 inch, 6.35 mm or 5 + computational cells thick but the simulated RF reflects off the surface (IMO). I need a copper model that reflects 2.5 GHz RF with a skin depth of 6 mm and resistance equal to copper at that frequency. But I have no idea where to start.
I have a suggestion for the model....I fully agree, a large number (say every 10 degrees: 36 such antennas) of short antennas around the circumference, would ensure axi-symmetry .
Good idea :)
Another way may be the useage a larger number of dipoles to form a loop like antenna structure?
Please, no straight long dipole antennas: straight long antennas distort the symmetry of the modes !
Cone dimensions (CrazyEddie).
Dipole orientation like in the picture(YangShell), but more and shorter antennas around the circumference near the big end.
Note that the YangShell design with only two dipoles in this configuration showed TE01 but deformed.
Circular i think. The field vectors are closer/more equal to the TE01 mode.I have a suggestion for the model....I fully agree, a large number (say every 10 degrees: 36 such antennas) of short antennas around the circumference, would ensure axi-symmetry .
Good idea :)
Another way may be the useage a larger number of dipoles to form a loop like antenna structure?
Please, no straight long dipole antennas: straight long antennas distort the symmetry of the modes !
Cone dimensions (CrazyEddie).
Dipole orientation like in the picture(YangShell), but more and shorter antennas around the circumference near the big end.
Note that the YangShell design with only two dipoles in this configuration showed TE01 but deformed.
In the following drawings we have 36 short dipole antennas, arranged circularly every 10° near the big base, at 22.6073% of the distance between the ends, as recommended by Rodal. How would you dispose them longitudinally (i.e. along their greatest length):
- radially,
- or circularly (tangent to the perimeter of the circle they draw)?
My guess is circularly (to simulate a loop). But in the drawing you brought with only a couple of them, it seems they are disposed radially so I think we should clarify.
The diameter of the of the 36 short antennas (the distance between the antennas in opposite locations) should be much smaller than the diameter of the truncated cone at the location of the antennas, as I showed with images previously, since the effective diameter of the axial magnetic field is much smaller than the diameter of the truncated cone. The diameter should be based on the proportion of the images provided for the axial magnetic field.Circular i think. The field vectors are closer/more equal to the TE01 mode.I have a suggestion for the model....I fully agree, a large number (say every 10 degrees: 36 such antennas) of short antennas around the circumference, would ensure axi-symmetry .
Good idea :)
Another way may be the useage a larger number of dipoles to form a loop like antenna structure?
Please, no straight long dipole antennas: straight long antennas distort the symmetry of the modes !
Cone dimensions (CrazyEddie).
Dipole orientation like in the picture(YangShell), but more and shorter antennas around the circumference near the big end.
Note that the YangShell design with only two dipoles in this configuration showed TE01 but deformed.
In the following drawings we have 36 short dipole antennas, arranged circularly every 10° near the big base, at 22.6073% of the distance between the ends, as recommended by Rodal. How would you dispose them longitudinally (i.e. along their greatest length):
- radially,
- or circularly (tangent to the perimeter of the circle they draw)?
My guess is circularly (to simulate a loop). But in the drawing you brought with only a couple of them, it seems they are disposed radially so I think we should clarify.
Then there is no basis to justify those Drude constant models presently used in the Meep analysis of the frustum: they result in power losses that are several orders of magnitude smaller than what they should be. Q's of millions do not make any sense. It doesn't make sense as an engineering model and it doesn't make sense as a theoretical model.Sad to say I threw away the papers containing that work.QuoteI have not seen any basis to justify the Drude constants to be realisitc for microwave frequencies.
@Deltamass - Do you want to respond to Dr. Rodal? As I recall you did devote significant effort to develop the Drude model and did use the correct range of microwave frequency in your derivation.
Circular i think. The field vectors are closer/more equal to the TE01 mode.
The diameter of the of the 36 short antennas (the distance between the antennas in opposite locations) should be much smaller than the diameter of the truncated cone at the location of the antennas, as I showed with images previously, since the effective diameter of the axial magnetic field is much smaller than the diameter of the truncated cone. The diameter should be based on the proportion of the images provided for the axial magnetic field.
Making the diameter too large will interfere with the transverse electric field in the azimuthal direction which would degrade the mode shape.
Circular i think. The field vectors are closer/more equal to the TE01 mode.
The Stonehenge arrangement then :)The diameter of the of the 36 short antennas (the distance between the antennas in opposite locations) should be much smaller than the diameter of the truncated cone at the location of the antennas, as I showed with images previously, since the effective diameter of the axial magnetic field is much smaller than the diameter of the truncated cone. The diameter should be based on the proportion of the images provided for the axial magnetic field.
Making the diameter too large will interfere with the transverse electric field in the azimuthal direction which would degrade the mode shape.
I remember. Will be difficult to put so many dipole antennas within such a small circle (about 3 to 4 cm wide if you want to make it the same size as a real loop antenna).
There are some possibilities:The diameter of the of the 36 short antennas (the distance between the antennas in opposite locations) should be much smaller than the diameter of the truncated cone at the location of the antennas, as I showed with images previously, since the effective diameter of the axial magnetic field is much smaller than the diameter of the truncated cone. The diameter should be based on the proportion of the images provided for the axial magnetic field.Circular i think. The field vectors are closer/more equal to the TE01 mode.I have a suggestion for the model....I fully agree, a large number (say every 10 degrees: 36 such antennas) of short antennas around the circumference, would ensure axi-symmetry .
Good idea :)
Another way may be the useage a larger number of dipoles to form a loop like antenna structure?
Please, no straight long dipole antennas: straight long antennas distort the symmetry of the modes !
Cone dimensions (CrazyEddie).
Dipole orientation like in the picture(YangShell), but more and shorter antennas around the circumference near the big end.
Note that the YangShell design with only two dipoles in this configuration showed TE01 but deformed.
In the following drawings we have 36 short dipole antennas, arranged circularly every 10° near the big base, at 22.6073% of the distance between the ends, as recommended by Rodal. How would you dispose them longitudinally (i.e. along their greatest length):
- radially,
- or circularly (tangent to the perimeter of the circle they draw)?
My guess is circularly (to simulate a loop). But in the drawing you brought with only a couple of them, it seems they are disposed radially so I think we should clarify.
Making the diameter too large will interfere with the transverse electric field in the azimuthal direction which would degrade the mode shape.
1) The diameter given by the images I provided is still significantly larger than the diameter of the loop used by NASA on the side of the cone (that was not successful at producing TE012 on a consistent basis, hence they had to switch to TM212 transverse magnetic mode).
2) If 36 antennas results in too many antennas of too short length each, then let's use common sense, and just reduce the number of antennas based on a sensible short length. Having 18 antennas is much better than having one straight antenna. Even 6 antennas is better than one straight antenna :)
3) As I understand it, Shell is not going to use a circular frustum anyway, but is going to use a polygon. I forgot how many sides. Let's say that Shell is going to use a hexagon, then use 6 antennas. If Shell uses a pentagon, use 5 antennas. If Shell uses a heptagon, use 7 antenas. You get the idea
1) The diameter given by the images I provided is still significantly larger than the diameter of the loop used by NASA on the side of the cone (that was not successful at producing TE012 on a consistent basis, hence they had to switch to TM212 transverse magnetic mode).
I remember the discussion with the (too) large loop antenna and then the smaller loop antenna with its circumference being equal to λ/4, both near the big end and at the center of axi-symmetry. But I don't recall you specified a different diameter. Can you provide a link to this dimension?2) If 36 antennas results in too many antennas of too short length each, then let's use common sense, and just reduce the number of antennas based on a sensible short length. Having 18 antennas is much better than having one straight antenna. Even 6 antennas is better than one straight antenna :)
Of course. See new picture below.3) As I understand it, Shell is not going to use a circular frustum anyway, but is going to use a polygon. I forgot how many sides. Let's say that Shell is going to use a hexagon, then use 6 antennas. If Shell uses a pentagon, use 5 antennas. If Shell uses a heptagon, use 7 antenas. You get the idea
We are currently trying to calculate antennas shapes and locations for Shell's 2nd generation frustum, using flat ends, powered by a 2.47 GHz magnetron at 100% duty cycle. It is true her 1st gen is a hexagonal truncated pyramid (http://ayuba.fr/images/emdrive/see-shell-testbed.png), but her 2nd gen is a truncated cone with a cylindrical neck fitting an axially adjustable small circular end, with the following dimensions:
Db = 295 mm
Ds = 160 mm
L = 163 mm (173 mm according to TT's spreadsheet, but this will be the opportunity to test the true resonant mode at various lengths, thanks to the axially adjustable small end)
...
I don't think we know the impedance match between the magnetron and the frustum, and therefore don't know how much of the InputPower is actually getting coupled.
...
Admittedly I also don't know if reflected vs delivered power makes any difference in "thrust"....
...
We don't have knowledge of "impedance match between the magnetron and the frustum" for most reported experiments, do we?.
...
The raw input power should also be used for rfmwguy's experiment, just as it has been done for most other experiments.
...
Doc, not sure if you want to report ft 1, ft 2 and ft 2a on wiki test results but I am ok with Null on all three, or at least possible thrust below measurement threshold. I cannot yet resolve orders of 10 mg, i'd estimate my mechanical setup to be 100 mg at best.I very much appreciate your feedback and willingness to post the results as null. This speaks greatly of your scientific objectivity, which I applaud.
The laser displacement sensor coming next week will easily resolve this. Might be good idea to post letting other diy projects in on measurement resolution limits using a laser pointer system.
Your call doc...I'm good with it...
...
I don't think we know the impedance match between the magnetron and the frustum, and therefore don't know how much of the InputPower is actually getting coupled.
...
Admittedly I also don't know if reflected vs delivered power makes any difference in "thrust"....
...
We don't have knowledge of "impedance match between the magnetron and the frustum" for most reported experiments, do we?.
...
The raw input power should also be used for rfmwguy's experiment, just as it has been done for most other experiments.
...
I concede that using raw input power would be consistent with other reported data in the twiki.
Happily Rfmwguy has agreed to push forward and try to obtain better SNR. I agree that now is not the time to worry about detailed coupling and excitation frequency data when there are more important "bigger picture" items on the punch list. Characterization of the balance beam, for instance. ;D
Best wishes to the ongoing experiments!
Thanks,
James
..
Thanks for explaining that Harminv starts by turning the sources off. That makes lots of sense to me. It didn't make sense to calculate the Q with the sources on.
It doesn't make numerical sense to model the skin depth with a finite difference scheme on the same finite difference solution that you are solving for the frustum. It is not a question of computer resources. It would not make numerical sense to do that even if you would have the computer resources. Your matrix would be ill-conditioned. The numerical solution (even if you had the computer resources) would be unreliable due to ill-conditioning of the matrix.
If that were necessary to do, I would use two computer models: one for the frustum and another one for the copper, that would be solved independently at each step, and the solution would be iterated at each step. But I think that is unnecessary, since it is trivial to solve for the skin effect analytically, hence there is no need to do any numerical simulation of the skin depth, as it is well known and it can be solved analytically
Just think about it: how do you think that NASA calculated the Q, and obtained reasonable values using COMSOL Finite Element analysis?
Do you think that COMSOL modeled the skin depth (micrometer) with finite elements ?
Of course not.
I didn't know that you were modeling the copper <<as 1/4 inch, 6.35 mm or 5 + computational cells thick >> Did I understand that right? that you have 5 computational cells through the thickness of only 1/4 in of copper ?
Based on this, my conclusion is the following:
1) Ignore Q for these Meep analyses
2) Consider that power losses are not properly taken into account in these Meep analyses, hence steady-state is going to take much longer to be achieved in the Meep model than in reality (if ever)
3) The proper way to calculate power losses and hence Q would be to write code in Meep to introduce power losses proportional to the skin depth (which can be calculated with a simple expression) times the surface integral of the square of the magnetic field at the inner surface of the copper cavity.
_________
PS: I still think that running different values of the Drude model to come up with realistic power losses would make much more sense than the present Drude constants. The purpose of the Drude model should be to have realistic power losses, and the present power losses are orders of magnitude smaller than what they should be. It would be an "ad hoc" solution, purely for engineering purposes, but at least it would give realistic values of power losses.
Then there is no basis to justify those Drude constant models presently used in the Meep analysis of the frustum: they result in power losses that are several orders of magnitude smaller than what they should be. Q's of millions do not make any sense. It doesn't make sense as an engineering model and it doesn't make sense as a theoretical model.Sad to say I threw away the papers containing that work.QuoteI have not seen any basis to justify the Drude constants to be realisitc for microwave frequencies.
@Deltamass - Do you want to respond to Dr. Rodal? As I recall you did devote significant effort to develop the Drude model and did use the correct range of microwave frequency in your derivation.
I didn't get as much time in the shop as I wanted but did get it a little more cleaned up and a couple of odds and ends done. Re-laying out the magnetron power supply. found one at Re-Store for 10 bucks and spun the % off wheel and ended up getting it for 4 bucks. ;)Yay! Good job shell. I think we've just seen our new international flight test facility for the first time :D
I have new wire for the faraday cage arriving this tuesday and I've a few more adjustments on the leveling and vibration isolation using sorbothane pads. Got work to do on the balance beam but it is very sensitive but wants to oscillate way too much.
Here are a few pics for those who want to know.
Shell
My problem is I'm way way picky and I do not like to fail, it has to be the best I can do. You know the feeling. I'm just amazed at what you have done with so little...dam good work rfmwguy.I didn't get as much time in the shop as I wanted but did get it a little more cleaned up and a couple of odds and ends done. Re-laying out the magnetron power supply. found one at Re-Store for 10 bucks and spun the % off wheel and ended up getting it for 4 bucks. ;)Yay! Good job shell. I think we've just seen our new international flight test facility for the first time :D
I have new wire for the faraday cage arriving this tuesday and I've a few more adjustments on the leveling and vibration isolation using sorbothane pads. Got work to do on the balance beam but it is very sensitive but wants to oscillate way too much.
Here are a few pics for those who want to know.
Shell
How much weight do you reckon will be on your balance? I ask because I see big boxy stuff!My problem is I'm way way picky and I do not like to fail, it has to be the best I can do. You know the feeling. I'm just amazed at what you have do with so little...dam good work rfmwguy.I didn't get as much time in the shop as I wanted but did get it a little more cleaned up and a couple of odds and ends done. Re-laying out the magnetron power supply. found one at Re-Store for 10 bucks and spun the % off wheel and ended up getting it for 4 bucks. ;)Yay! Good job shell. I think we've just seen our new international flight test facility for the first time :D
I have new wire for the faraday cage arriving this tuesday and I've a few more adjustments on the leveling and vibration isolation using sorbothane pads. Got work to do on the balance beam but it is very sensitive but wants to oscillate way too much.
Here are a few pics for those who want to know.
Shell
Dr. Rodal. I am going to be using a round cone in this hunt for TE012, I've got the O2 free copper and I believe it will be my best shot at generating a TE012 mode. The unknown is the antenna.Circular i think. The field vectors are closer/more equal to the TE01 mode.
The Stonehenge arrangement then :)The diameter of the of the 36 short antennas (the distance between the antennas in opposite locations) should be much smaller than the diameter of the truncated cone at the location of the antennas, as I showed with images previously, since the effective diameter of the axial magnetic field is much smaller than the diameter of the truncated cone. The diameter should be based on the proportion of the images provided for the axial magnetic field.
Making the diameter too large will interfere with the transverse electric field in the azimuthal direction which would degrade the mode shape.
I remember. Will be difficult to put so many dipole antennas within such a small circle (about 3 to 4 cm wide if you want to make it the same size as a real loop antenna).
1) The diameter given by the images I provided is still significantly larger than the diameter of the loop used by NASA on the side of the cone (that was not successful at producing TE012 on a consistent basis, hence they had to switch to TM212 transverse magnetic mode).
2) If 36 antennas results in too many antennas of too short length each, then let's use common sense, and just reduce the number of antennas based on a sensible short length. Having 18 antennas is much better than having one straight antenna. Even 6 antennas is better than one straight antenna :)
3) As I understand it, Shell is not going to use a circular frustum anyway, but is going to use a polygon. I forgot how many sides. Let's say that Shell is going to use a hexagon, then use 6 antennas. If Shell uses a pentagon, use 5 antennas. If Shell uses a heptagon, use 7 antenas. You get the idea
2-3 kilos. Boxy is for stability. And please don't call my faraday cage like a friend did today. He said it looks like a chicken coop. sigh.....How much weight do you reckon will be on your balance? I ask because I see big boxy stuff!My problem is I'm way way picky and I do not like to fail, it has to be the best I can do. You know the feeling. I'm just amazed at what you have do with so little...dam good work rfmwguy.I didn't get as much time in the shop as I wanted but did get it a little more cleaned up and a couple of odds and ends done. Re-laying out the magnetron power supply. found one at Re-Store for 10 bucks and spun the % off wheel and ended up getting it for 4 bucks. ;)Yay! Good job shell. I think we've just seen our new international flight test facility for the first time :D
I have new wire for the faraday cage arriving this tuesday and I've a few more adjustments on the leveling and vibration isolation using sorbothane pads. Got work to do on the balance beam but it is very sensitive but wants to oscillate way too much.
Here are a few pics for those who want to know.
Shell
Is the "perfect metal" model tantamount to an infinite Q with zero resistivity ?Then there is no basis to justify those Drude constant models presently used in the Meep analysis of the frustum: they result in power losses that are several orders of magnitude smaller than what they should be. Q's of millions do not make any sense. It doesn't make sense as an engineering model and it doesn't make sense as a theoretical model.Sad to say I threw away the papers containing that work.QuoteI have not seen any basis to justify the Drude constants to be realisitc for microwave frequencies.
@Deltamass - Do you want to respond to Dr. Rodal? As I recall you did devote significant effort to develop the Drude model and did use the correct range of microwave frequency in your derivation.
I think maybe I'll just go back to using perfect metal and not bother discussing Drude models and copper any further.
I didn't get as much time in the shop as I wanted but did get it a little more cleaned up and a couple of odds and ends done. Re-laying out the magnetron power supply. found one at Re-Store for 10 bucks and spun the % off wheel and ended up getting it for 4 bucks. ;)I'm impressed by how clean and neat everything looks !
I have new wire for the faraday cage arriving this tuesday and I've a few more adjustments on the leveling and vibration isolation using sorbothane pads. Got work to do on the balance beam but it is very sensitive but wants to oscillate way too much.
Here are a few pics for those who want to know.
Shell
Thanks, just photoshopped out the dirt. :DI didn't get as much time in the shop as I wanted but did get it a little more cleaned up and a couple of odds and ends done. Re-laying out the magnetron power supply. found one at Re-Store for 10 bucks and spun the % off wheel and ended up getting it for 4 bucks. ;)I'm impressed by how clean and neat everything looks !
I have new wire for the faraday cage arriving this tuesday and I've a few more adjustments on the leveling and vibration isolation using sorbothane pads. Got work to do on the balance beam but it is very sensitive but wants to oscillate way too much.
Here are a few pics for those who want to know.
Shell
Its been a personal challenge to build low budget with common everyday items. Plus is that it excersises mind, minus is it needs higher resolution. No matter, I picked up a used lds sensor cheap and willl be able to see painfully small beam displacements.My problem is I'm way way picky and I do not like to fail, it has to be the best I can do. You know the feeling. I'm just amazed at what you have done with so little...dam good work rfmwguy.I didn't get as much time in the shop as I wanted but did get it a little more cleaned up and a couple of odds and ends done. Re-laying out the magnetron power supply. found one at Re-Store for 10 bucks and spun the % off wheel and ended up getting it for 4 bucks. ;)Yay! Good job shell. I think we've just seen our new international flight test facility for the first time :D
I have new wire for the faraday cage arriving this tuesday and I've a few more adjustments on the leveling and vibration isolation using sorbothane pads. Got work to do on the balance beam but it is very sensitive but wants to oscillate way too much.
Here are a few pics for those who want to know.
Shell
Thanks, that made me feel very good.Its been a personal challenge to build low budget with common everyday items. Plus is that it excersises mind, minus is it needs higher resolution. No matter, I picked up a used lds sensor cheap and willl be able to see painfully small beam displacements.My problem is I'm way way picky and I do not like to fail, it has to be the best I can do. You know the feeling. I'm just amazed at what you have done with so little...dam good work rfmwguy.I didn't get as much time in the shop as I wanted but did get it a little more cleaned up and a couple of odds and ends done. Re-laying out the magnetron power supply. found one at Re-Store for 10 bucks and spun the % off wheel and ended up getting it for 4 bucks. ;)Yay! Good job shell. I think we've just seen our new international flight test facility for the first time :D
I have new wire for the faraday cage arriving this tuesday and I've a few more adjustments on the leveling and vibration isolation using sorbothane pads. Got work to do on the balance beam but it is very sensitive but wants to oscillate way too much.
Here are a few pics for those who want to know.
Shell
I don't mind thermal lift if I can extract thrust signatures off of the curve. That remains to be seen.
You are a perfectionist, I can see that in your build. I am duly impressed as one builder to another 8)
You can offset some of the weight with a spring anchored vertically above.Counter balance without adding the issues of a spring?
Something is bugging me about the 30% power cycle from the NSF-1701 tests. The on/off cycle repeats faithfully every 25 seconds. It hums for 10 seconds and then there's 15 seconds of silence. I'm not much of a mathematician but that seems to me more like 40%. I realize hum does not equal microwave output but I imagined the two would be closely correlated. Perhaps there's an arbitrary 2.5 seconds of warm up time allowed in the calculation?Tube warm up time...no doubt about it.
With the remote triggered, full power activation I'm sure this will become irrelevant but if anyone has a simple explanation I would be most grateful.
After 3 flight tests and several static tests, I have a few thoughts on the project. First, the forces we are trying to measure are exceedingly small; so much so, that thermal currents can easily swamp what is reportedly thrust. Second, digital scales can easily be fooled by EMI, providing false readings when the magnetron fires up. Third, this has to be approached with a neutral attitude.(Bold added for emphasis)
...
There are also experiments that have already been done, that had null results but have not yet been properly documented in the EM Drive wiki for experimental results, for example: Mulletron's experiment who deserves to be recognized as the true leader in these Do-It-Yourself experiments, had null results documented in early threads, also the experiments with the experimenter that had constant cross-section waveguide and was using dielectric inserts, gave null results.
I understand that null results in these experiments don't close the book, as any experiment is limited on what can be tested (type of force measurement, set-up, etc.), but as Shell, says, "there is no bad data" and we should not forget those null results as well, as they are part of the big picture.
The big picture that is emerging is that if there is any EM Drive force (yes, it may be zero), its force/InputPower magnitude is of the very small magnitude reported by NASA (~0.001 Newton/KiloWatt) and by Dresden University (Tajmar) (0.00003 to 0.00013 Newton/KiloWatt) but not at all the thousands of times greater magnitudes reported by Shawyer (0.4 Newton/KiloWatt) and Yang (1 Newton/KiloWatt) - who nobody has been able to reproduce-
The force/InputPower reported by Iulian Berca was similar to the one reported by NASA.
We have been testing for a couple weeks now without any success.
Indeed. But bear in mind that both the spring and the pivot counterbalance solution potentially introduce extra stiction.I think rfmwguy is seeing stiction from someplace else other than the knife edge, maybe from his liquid conductor? I would take it out of the loop (take out the copper wires) and see what amount of stiction he is then seeing.
This is a good idea, although it may take more initial energy to get it moving because of more contact surface. I think both my galinstan and support wire assemble at end of beam might be sticky. First, I'll run a video, maybe tonight, with galinstan cups taken out of the way and simply do a 500 mg weight swing. Should be interesting.Indeed. But bear in mind that both the spring and the pivot counterbalance solution potentially introduce extra stiction.I think rfmwguy is seeing stiction from someplace else other than the knife edge, maybe from his liquid conductor? I would take it out of the loop (take out the copper wires) and see what amount of stiction he is then seeing.
Personal preference I went with a rolling knife edge and haven't even been able to measure any stiction and my scales are set to .01 gram.
This is a good idea, although it may take more initial energy to get it moving because of more contact surface. I think both my galinstan and support wire assemble at end of beam might be sticky. First, I'll run a video, maybe tonight, with galinstan cups taken out of the way and simply do a 500 mg weight swing. Should be interesting.Indeed. But bear in mind that both the spring and the pivot counterbalance solution potentially introduce extra stiction.I think rfmwguy is seeing stiction from someplace else other than the knife edge, maybe from his liquid conductor? I would take it out of the loop (take out the copper wires) and see what amount of stiction he is then seeing.
Personal preference I went with a rolling knife edge and haven't even been able to measure any stiction and my scales are set to .01 gram.
RFMWGUY wrote (elsewhere) this great synopis:Quote from: RFMWGUYAfter 3 flight tests and several static tests, I have a few thoughts on the project. First, the forces we are trying to measure are exceedingly small; so much so, that thermal currents can easily swamp what is reportedly thrust. Second, digital scales can easily be fooled by EMI, providing false readings when the magnetron fires up. Third, this has to be approached with a neutral attitude.(Bold added for emphasis)
I fully agree. Great summary.
There are previous NULL results that have not been documented in the EM Drive Wiki:...
There are also experiments that have already been done, that had null results but have not yet been properly documented in the EM Drive wiki for experimental results, for example: Mulletron's experiment who deserves to be recognized as the true leader in these Do-It-Yourself experiments, had null results documented in early threads, also the experiments with the experimenter that had constant cross-section waveguide and was using dielectric inserts, gave null results.
I understand that null results in these experiments don't close the book, as any experiment is limited on what can be tested (type of force measurement, set-up, etc.), but as Shell, says, "there is no bad data" and we should not forget those null results as well, as they are part of the big picture.
The big picture that is emerging is that if there is any EM Drive force (yes, it may be zero), its force/InputPower magnitude is of the very small magnitude reported by NASA (~0.001 Newton/KiloWatt) and by Dresden University (Tajmar) (0.00003 to 0.00013 Newton/KiloWatt) but not at all the thousands of times greater magnitudes reported by Shawyer (0.4 Newton/KiloWatt) and Yang (1 Newton/KiloWatt) - who nobody has been able to reproduce-
The force/InputPower reported by Iulian Berca was similar to the one reported by NASA.
The Do-It-Yourself experiments are showing that if there is a thrust force, it is at most of the order of what has been reported by NASA and Tajmar (0.001 Newton/KiloWatt or less) rather than what has been reported by Shawyer and Yang (0.4 to 1 Newton/KiloWatt -- that nobody else has reproduced). Although RFMWGUY has not yet measured S11 or reported a Q, please notice that Mulletron (the first Do-It-Yourself) did measure and report the resonant response peaks for his truncated cone, that clearly showed resonant peaks for his null experimental results.
This is reminding me more and more of the "cold fusion" experimental attempts at replication after the non-properly-peer-reviewed announcement from Fleischmann and Pons (which also has in common that currently, 25 years afterwards, still there is no accepted theoretical model by the mainstream scientific community which would allow cold fusion to occur)....QuoteMany scientists tried to replicate the experiment with the few details available. Hopes faded due to the large number of negative replications, the withdrawal of many positive replications, the discovery of flaws and sources of experimental error in the original experiment,
Given these results, it would be nice to have an update from other "Do-It-Yourself" people: Elizabeth, Dr. BagelBytes, etc.
Unless you have something like diamond or ruby or sapphire at the bearing surface, the nick you get, which might be almost invisible to the naked eye, will cause stiction. I think that Shells did well not to cannibalise her jewelry for the cause 8)Sure it can be a issue and I will not cannibalize any of my costume jewelery either. :D
ETA The Mettler H10 uses sapphire bearings.
This is a good idea, although it may take more initial energy to get it moving because of more contact surface. I think both my galinstan and support wire assemble at end of beam might be sticky. First, I'll run a video, maybe tonight, with galinstan cups taken out of the way and simply do a 500 mg weight swing. Should be interesting.Indeed. But bear in mind that both the spring and the pivot counterbalance solution potentially introduce extra stiction.I think rfmwguy is seeing stiction from someplace else other than the knife edge, maybe from his liquid conductor? I would take it out of the loop (take out the copper wires) and see what amount of stiction he is then seeing.
Personal preference I went with a rolling knife edge and haven't even been able to measure any stiction and my scales are set to .01 gram.
I agree with deltaMass that the stiction is most probably coming from the metal to metal contact points (due to plastic deformation, beyond the yield limit of the material, and stick-friction).
It would be helpful to lubricate with motor oil the contacting surfaces prior to contact. Most metal to metal roller bearings, are lubricated and never run dry, even though the contact surfaces are made with hardened metals and the radii of curvature are carefully designed to avoid plastic yielding
Analyses as well as experiments of contact surfaces show how important is lubrication at contact points !!!
Remember to re-lubricate prior to each and every tests
EDIT: Assuming that RFMWguy has metal to metal contacting surfaces...This is a good idea, although it may take more initial energy to get it moving because of more contact surface. I think both my galinstan and support wire assemble at end of beam might be sticky. First, I'll run a video, maybe tonight, with galinstan cups taken out of the way and simply do a 500 mg weight swing. Should be interesting.Indeed. But bear in mind that both the spring and the pivot counterbalance solution potentially introduce extra stiction.I think rfmwguy is seeing stiction from someplace else other than the knife edge, maybe from his liquid conductor? I would take it out of the loop (take out the copper wires) and see what amount of stiction he is then seeing.
Personal preference I went with a rolling knife edge and haven't even been able to measure any stiction and my scales are set to .01 gram.
I agree with deltaMass that the stiction is most probably coming from the metal to metal contact points (due to plastic deformation, beyond the yield limit of the material, and stick-friction).
It would be helpful to lubricate with motor oil the contacting surfaces prior to contact. Most metal to metal roller bearings, are lubricated and never run dry, even though the contact surfaces are made with hardened metals and the radii of curvature are carefully designed to avoid plastic yielding
Analyses as well as experiments of contact surfaces show how important is lubrication at contact points !!!
Remember to re-lubricate prior to each and every tests
No motor oil! It's sticky, collects dirt and dust. Dry graphite film.
http://www.instructables.com/id/How-to-Lubricate-a-Lock-Using-Graphite-From-a-Penc/
Shell
Added: Slick huh?
1) The diameter given by the images I provided is still significantly larger than the diameter of the loop used by NASA on the side of the cone (that was not successful at producing TE012 on a consistent basis, hence they had to switch to TM212 transverse magnetic mode).
I remember the discussion with the (too) large loop antenna and then the smaller loop antenna with its circumference being equal to λ/4, both near the big end and at the center of axi-symmetry. But I don't recall you specified a different diameter. Can you provide a link to this dimension?2) If 36 antennas results in too many antennas of too short length each, then let's use common sense, and just reduce the number of antennas based on a sensible short length. Having 18 antennas is much better than having one straight antenna. Even 6 antennas is better than one straight antenna :)
Of course. See new picture below. The 12 dipole antennas drew a circle having a diameter of 46.4 mm (I based that on λ/4 in this region) at a distance of 36.85 mm from the big base as you advised (http://forum.nasaspaceflight.com/index.php?topic=38203.msg1419037#msg1419037).3) As I understand it, Shell is not going to use a circular frustum anyway, but is going to use a polygon. I forgot how many sides. Let's say that Shell is going to use a hexagon, then use 6 antennas. If Shell uses a pentagon, use 5 antennas. If Shell uses a heptagon, use 7 antenas. You get the idea
We are currently trying to calculate antennas shapes and locations for Shell's 2nd generation frustum, using flat ends, powered by a 2.47 GHz magnetron at 100% duty cycle. It is true her 1st gen is a hexagonal truncated pyramid (http://ayuba.fr/images/emdrive/see-shell-testbed.png), but her 2nd gen is a truncated cone with a cylindrical neck fitting an axially adjustable small circular end, with the following dimensions:
Db = 295 mm
Ds = 160 mm
L = 163 mm (173 mm according to TT's spreadsheet, but this will be the opportunity to test the true resonant mode at various lengths, thanks to the axially adjustable small end)
Those issues can be addressed by re-lubrication prior to each and every test. Graphite is better than nothing (apparently the situation at the moment) but much inferior to oil lubrication not only as shown in my industrial experience but also in myriads of industrial applications.This is a good idea, although it may take more initial energy to get it moving because of more contact surface. I think both my galinstan and support wire assemble at end of beam might be sticky. First, I'll run a video, maybe tonight, with galinstan cups taken out of the way and simply do a 500 mg weight swing. Should be interesting.Indeed. But bear in mind that both the spring and the pivot counterbalance solution potentially introduce extra stiction.I think rfmwguy is seeing stiction from someplace else other than the knife edge, maybe from his liquid conductor? I would take it out of the loop (take out the copper wires) and see what amount of stiction he is then seeing.
Personal preference I went with a rolling knife edge and haven't even been able to measure any stiction and my scales are set to .01 gram.
I agree with deltaMass that the stiction is most probably coming from the metal to metal contact points (due to plastic deformation, beyond the yield limit of the material, and stick-friction).
It would be helpful to lubricate with motor oil the contacting surfaces prior to contact. Most metal to metal roller bearings, are lubricated and never run dry, even though the contact surfaces are made with hardened metals and the radii of curvature are carefully designed to avoid plastic yielding
Analyses as well as experiments of contact surfaces show how important is lubrication at contact points !!!
Remember to re-lubricate prior to each and every tests
No motor oil! It's sticky, collects dirt and dust. Dry graphite film.
http://www.instructables.com/id/How-to-Lubricate-a-Lock-Using-Graphite-From-a-Penc/
Shell
Added: Slick huh?
The "dirt" collected by oil at the contact surface is not just from the environment but it is due to wear and micro-fracturing of the contacting surface asperities: it is an essential benefit of a viscous liquid lubricant like oil to collect and hence remove those particles from the contact surface Graphite (since it is not a liquid) does not provide liquid lubrication and hence it is not as effective.
Graphite is one solution when the application cannot afford to have oil injection and filtering, but in this case is there a problem with re-lubricating every time?
Try both methods (oil lubrication and graphite) and compare the results (both are going to be certainly better than dry contact :) )
...Oh, OK :)
Yes Dr. Rodel but I have a composite graphite rod sliding on graphite. Slick or not?
Shell
http://www.cstsales.com/carbon_rods.html...Oh, OK :)
Yes Dr. Rodel but I have a composite graphite rod sliding on graphite. Slick or not?
Shell
I was referring to oil lubrication of metal-to-metal contact (isn't that what RFMWguy has?), not to composite to metal contact.
What is the polymer matrix for the graphite fibers, is it epoxy? Is it contacting metal?
Besides graphite powder you could also try Teflon (PTFE) on the contacting surface.
http://www.cstsales.com/carbon_rods.html...Oh, OK :)
Yes Dr. Rodel but I have a composite graphite rod sliding on graphite. Slick or not?
Shell
I was referring to oil lubrication of metal-to-metal contact (isn't that what RFMWguy has?), not to composite to metal contact.
What is the polymer matrix for the graphite fibers, is it epoxy? Is it contacting metal?
Besides graphite powder you could also try Teflon (PTFE) on the contacting surface.
They order it from a company in Switzerland and so far I'm very impressed with it.http://www.cstsales.com/carbon_rods.html...Oh, OK :)
Yes Dr. Rodel but I have a composite graphite rod sliding on graphite. Slick or not?
Shell
I was referring to oil lubrication of metal-to-metal contact (isn't that what RFMWguy has?), not to composite to metal contact.
What is the polymer matrix for the graphite fibers, is it epoxy? Is it contacting metal?
Besides graphite powder you could also try Teflon (PTFE) on the contacting surface.
Yeah, according to the data sheets, they are using Bisphenol F Epoxy resin with a Tg of at least 100 Deg C at a fiber to resin ratio of 67%
You are right with the vertical feed lines.1) The diameter given by the images I provided is still significantly larger than the diameter of the loop used by NASA on the side of the cone (that was not successful at producing TE012 on a consistent basis, hence they had to switch to TM212 transverse magnetic mode).
I remember the discussion with the (too) large loop antenna and then the smaller loop antenna with its circumference being equal to λ/4, both near the big end and at the center of axi-symmetry. But I don't recall you specified a different diameter. Can you provide a link to this dimension?2) If 36 antennas results in too many antennas of too short length each, then let's use common sense, and just reduce the number of antennas based on a sensible short length. Having 18 antennas is much better than having one straight antenna. Even 6 antennas is better than one straight antenna :)
Of course. See new picture below. The 12 dipole antennas drew a circle having a diameter of 46.4 mm (I based that on λ/4 in this region) at a distance of 36.85 mm from the big base as you advised (http://forum.nasaspaceflight.com/index.php?topic=38203.msg1419037#msg1419037).3) As I understand it, Shell is not going to use a circular frustum anyway, but is going to use a polygon. I forgot how many sides. Let's say that Shell is going to use a hexagon, then use 6 antennas. If Shell uses a pentagon, use 5 antennas. If Shell uses a heptagon, use 7 antenas. You get the idea
We are currently trying to calculate antennas shapes and locations for Shell's 2nd generation frustum, using flat ends, powered by a 2.47 GHz magnetron at 100% duty cycle. It is true her 1st gen is a hexagonal truncated pyramid (http://ayuba.fr/images/emdrive/see-shell-testbed.png), but her 2nd gen is a truncated cone with a cylindrical neck fitting an axially adjustable small circular end, with the following dimensions:
Db = 295 mm
Ds = 160 mm
L = 163 mm (173 mm according to TT's spreadsheet, but this will be the opportunity to test the true resonant mode at various lengths, thanks to the axially adjustable small end)
Interesting idea worthy of sacrificing a few brain cells using the 12 vertically raised dipoles.
The first thing that I thought was how will the vertical sections deform the mode pattern? as it seems it will "wall off" the center section changing cavity tune.
You get kudos for selecting a product made with a pultrusion method, which is definitely the best manufacturing method to get high fiber to resin ratio for long rods, ensuring maximum bending stiffness/weight. The carbon fiber was made in Japan (they use Toho or Torayca as the carbon fiber supplier).They order it from a company in Switzerland and so far I'm very impressed with it.http://www.cstsales.com/carbon_rods.html...Oh, OK :)
Yes Dr. Rodel but I have a composite graphite rod sliding on graphite. Slick or not?
Shell
I was referring to oil lubrication of metal-to-metal contact (isn't that what RFMWguy has?), not to composite to metal contact.
What is the polymer matrix for the graphite fibers, is it epoxy? Is it contacting metal?
Besides graphite powder you could also try Teflon (PTFE) on the contacting surface.
Yeah, according to the data sheets, they are using Bisphenol F Epoxy resin with a Tg of at least 100 Deg C at a fiber to resin ratio of 67%
You are right with the vertical feed lines.1) The diameter given by the images I provided is still significantly larger than the diameter of the loop used by NASA on the side of the cone (that was not successful at producing TE012 on a consistent basis, hence they had to switch to TM212 transverse magnetic mode).
I remember the discussion with the (too) large loop antenna and then the smaller loop antenna with its circumference being equal to λ/4, both near the big end and at the center of axi-symmetry. But I don't recall you specified a different diameter. Can you provide a link to this dimension?2) If 36 antennas results in too many antennas of too short length each, then let's use common sense, and just reduce the number of antennas based on a sensible short length. Having 18 antennas is much better than having one straight antenna. Even 6 antennas is better than one straight antenna :)
Of course. See new picture below. The 12 dipole antennas drew a circle having a diameter of 46.4 mm (I based that on λ/4 in this region) at a distance of 36.85 mm from the big base as you advised (http://forum.nasaspaceflight.com/index.php?topic=38203.msg1419037#msg1419037).3) As I understand it, Shell is not going to use a circular frustum anyway, but is going to use a polygon. I forgot how many sides. Let's say that Shell is going to use a hexagon, then use 6 antennas. If Shell uses a pentagon, use 5 antennas. If Shell uses a heptagon, use 7 antenas. You get the idea
We are currently trying to calculate antennas shapes and locations for Shell's 2nd generation frustum, using flat ends, powered by a 2.47 GHz magnetron at 100% duty cycle. It is true her 1st gen is a hexagonal truncated pyramid (http://ayuba.fr/images/emdrive/see-shell-testbed.png), but her 2nd gen is a truncated cone with a cylindrical neck fitting an axially adjustable small circular end, with the following dimensions:
Db = 295 mm
Ds = 160 mm
L = 163 mm (173 mm according to TT's spreadsheet, but this will be the opportunity to test the true resonant mode at various lengths, thanks to the axially adjustable small end)
Interesting idea worthy of sacrificing a few brain cells using the 12 vertically raised dipoles.
The first thing that I thought was how will the vertical sections deform the mode pattern? as it seems it will "wall off" the center section changing cavity tune.
The original idea was to simulate a loop like antenna structure with a number of dipoles, not really the stonehenge style antenna forest.
Ironically there is a unit set up to do 5MW pulses that can adjust frequency within 10MHz of 930MHz ( frustum dimensions would not have to be exact that we could find resonance). At 10 microseconds the cooling of the frustum is managable without online cooling. Issue is would you see something in 10microseconds? Such a test hopefully could produce results that are an order of magnitude above background (into the ground no buoyant effects) or allow other phenomena (photon thruster leakage?) to be measurable. This will probably be experiment one as it is relatively cheap. If it's CoM I expect to see something on a digital scale within those 10us.
It's the duty cycle that matters in this case. If the 10 uS pulse happens once a Sec. you have a duty cycle of .001% and a time averaged power of 50 Watts, which is close to the power level the NASA team used. Because the mass you are trying to move is so much larger you would see less EM-Drive thrust (if it really exists) but you would also get more thermal, magnetic, and electrostatic effects. All of the EM-Drive "thrust" signatures disclosed so far have large time constants. So the effect of each individual 5 MW pulse would not be observable. This is just my opinion. I haven't done any EM-Drive experiments. I have been told I will soon be eating my words. I am still waiting...
For the simulation of a loop in a program like meep it may be possible to place a number of dipoles, one behind the other, to form a virtual wire. Around that path the magnetic field looks like the field around a real wire with a current flow.You are right with the vertical feed lines.1) The diameter given by the images I provided is still significantly larger than the diameter of the loop used by NASA on the side of the cone (that was not successful at producing TE012 on a consistent basis, hence they had to switch to TM212 transverse magnetic mode).
I remember the discussion with the (too) large loop antenna and then the smaller loop antenna with its circumference being equal to λ/4, both near the big end and at the center of axi-symmetry. But I don't recall you specified a different diameter. Can you provide a link to this dimension?2) If 36 antennas results in too many antennas of too short length each, then let's use common sense, and just reduce the number of antennas based on a sensible short length. Having 18 antennas is much better than having one straight antenna. Even 6 antennas is better than one straight antenna :)
Of course. See new picture below. The 12 dipole antennas drew a circle having a diameter of 46.4 mm (I based that on λ/4 in this region) at a distance of 36.85 mm from the big base as you advised (http://forum.nasaspaceflight.com/index.php?topic=38203.msg1419037#msg1419037).3) As I understand it, Shell is not going to use a circular frustum anyway, but is going to use a polygon. I forgot how many sides. Let's say that Shell is going to use a hexagon, then use 6 antennas. If Shell uses a pentagon, use 5 antennas. If Shell uses a heptagon, use 7 antenas. You get the idea
We are currently trying to calculate antennas shapes and locations for Shell's 2nd generation frustum, using flat ends, powered by a 2.47 GHz magnetron at 100% duty cycle. It is true her 1st gen is a hexagonal truncated pyramid (http://ayuba.fr/images/emdrive/see-shell-testbed.png), but her 2nd gen is a truncated cone with a cylindrical neck fitting an axially adjustable small circular end, with the following dimensions:
Db = 295 mm
Ds = 160 mm
L = 163 mm (173 mm according to TT's spreadsheet, but this will be the opportunity to test the true resonant mode at various lengths, thanks to the axially adjustable small end)
Interesting idea worthy of sacrificing a few brain cells using the 12 vertically raised dipoles.
The first thing that I thought was how will the vertical sections deform the mode pattern? as it seems it will "wall off" the center section changing cavity tune.
The original idea was to simulate a loop like antenna structure with a number of dipoles, not really the stonehenge style antenna forest.
This is a concern but how to connect those multiple dipole antennas to the frustum and the exterior? If you bring the vertical feed lines radially from the side walls they are no longer a "forest" but they become even longer and would look like bicycle spokes.
From this point of view a real loop antenna would be better indeed.
Do have a dumb question regarding thermal lift. Even if the magnetron is removed from the frustum assembly, it will generate heat around it's tube, thereby creating lift. If it is mechanically attached to the frustum, wouldn't the lift be simply recentered?
There will be less conductive heating of the frustum, depending on how far away and the interconnects used, but the maggy itself will remain hot, regardless...
Do have a dumb question regarding thermal lift. Even if the magnetron is removed from the frustum assembly, it will generate heat around it's tube, thereby creating lift. If it is mechanically attached to the frustum, wouldn't the lift be simply recentered?
There will be less conductive heating of the frustum, depending on how far away and the interconnects used, but the maggy itself will remain hot, regardless...
Yes, that's essentially correct. The magnetron is what gets hottest. As long as the magnetron is mechanically attached to the fustrum, the lift created by the natural thermal convection currents from the magnetron will carry the frustum with it, so having the magnetron attached to a waveguide doesn't seem to improve things since it makes everything heavier (bad) and there is no improvement because the magnetron is still mechanically attached.
A possible improvement is to provide more and better heat sink to the magnetron.
Pure aluminum has a conductivity of 230 W/m-K. Copper is better: 390 W/m-K which means a 70% increase in conduction over aluminum. That’s the good news. The down side of copper is that it weighs three times more than aluminum, costs the same on a per pound basis and is more difficult to machine. Due to limited high temperature formability, a copper extrusion will not yield the same detail as aluminum. Also, machining copper takes more time and wears cutters at a much higher rate. However, when an application is limited in conduction, copper is a commonly used alternative.
Forced convection from a fan is out of consideration as it would interfere with the measurement. Liquid cooling is difficult to implement.
@rfmwguyYes, I'm about to steal my wife's Cuisinart Grille and put underneath the frustum...Oh-oh...now I've done it...she reads my posts sometimes. :o
You could use a electrical heat source close to the magnetron position in your setup, and than look what the laserpoint does while a blind test... :)
Do have a dumb question regarding thermal lift. Even if the magnetron is removed from the frustum assembly, it will generate heat around it's tube, thereby creating lift. If it is mechanically attached to the frustum, wouldn't the lift be simply recentered?
There will be less conductive heating of the frustum, depending on how far away and the interconnects used, but the maggy itself will remain hot, regardless...
Yes, that's essentially correct. The magnetron is what gets hottest. As long as the magnetron is mechanically attached to the fustrum, the lift created by the natural thermal convection currents from the magnetron will carry the frustum with it, so having the magnetron attached to a waveguide doesn't seem to improve things since it makes everything heavier (bad) and there is no improvement because the magnetron is still mechanically attached.
A possible improvement is to provide more and better heat sink to the magnetron.
Pure aluminum has a conductivity of 230 W/m-K. Copper is better: 390 W/m-K which means a 70% increase in conduction over aluminum. That’s the good news. The down side of copper is that it weighs three times more than aluminum, costs the same on a per pound basis and is more difficult to machine. Due to limited high temperature formability, a copper extrusion will not yield the same detail as aluminum. Also, machining copper takes more time and wears cutters at a much higher rate. However, when an application is limited in conduction, copper is a commonly used alternative.
Forced convection from a fan is out of consideration as it would interfere with the measurement. Liquid cooling is difficult to implement.
Do have a dumb question regarding thermal lift. Even if the magnetron is removed from the frustum assembly, it will generate heat around it's tube, thereby creating lift. If it is mechanically attached to the frustum, wouldn't the lift be simply recentered?
There will be less conductive heating of the frustum, depending on how far away and the interconnects used, but the maggy itself will remain hot, regardless...
Yes, that's essentially correct. The magnetron is what gets hottest. As long as the magnetron is mechanically attached to the fustrum, the lift created by the natural thermal convection currents from the magnetron will carry the frustum with it, so having the magnetron attached to a waveguide doesn't seem to improve things since it makes everything heavier (bad) and there is no improvement because the magnetron is still mechanically attached.
A possible improvement is to provide more and better heat sink to the magnetron.
Pure aluminum has a conductivity of 230 W/m-K. Copper is better: 390 W/m-K which means a 70% increase in conduction over aluminum. That’s the good news. The down side of copper is that it weighs three times more than aluminum, costs the same on a per pound basis and is more difficult to machine. Due to limited high temperature formability, a copper extrusion will not yield the same detail as aluminum. Also, machining copper takes more time and wears cutters at a much higher rate. However, when an application is limited in conduction, copper is a commonly used alternative.
Forced convection from a fan is out of consideration as it would interfere with the measurement. Liquid cooling is difficult to implement.
This magnetron for example, requires water cooling:
http://www.ok1rr.com/tubes/burle/s94608e.pdf
Liquid Cooling:
Tube anode requires liquid cooling Liquid flow must start
before application of filament voltage and, preferably,
continue for several minutes after removing voltage.
Interlock filament power supply with liquid flow to prevent
tube damage due to inadequate liquid flow. When liquid is
water, use of distilled or filtered deionized water is
essential.
Water Flow .... (15 kW anode dissipation) 20.4 I/min. (5.5 gpm)
It is a 0.95GHz magnetron though (instead of 2.45GHz)
Even better would be a high power maser. Think about the 3dB BW (~1 Hz) and the Q ::)Do have a dumb question regarding thermal lift. Even if the magnetron is removed from the frustum assembly, it will generate heat around it's tube, thereby creating lift. If it is mechanically attached to the frustum, wouldn't the lift be simply recentered?
There will be less conductive heating of the frustum, depending on how far away and the interconnects used, but the maggy itself will remain hot, regardless...
Yes, that's essentially correct. The magnetron is what gets hottest. As long as the magnetron is mechanically attached to the fustrum, the lift created by the natural thermal convection currents from the magnetron will carry the frustum with it, so having the magnetron attached to a waveguide doesn't seem to improve things since it makes everything heavier (bad) and there is no improvement because the magnetron is still mechanically attached.
A possible improvement is to provide more and better heat sink to the magnetron.
Pure aluminum has a conductivity of 230 W/m-K. Copper is better: 390 W/m-K which means a 70% increase in conduction over aluminum. That’s the good news. The down side of copper is that it weighs three times more than aluminum, costs the same on a per pound basis and is more difficult to machine. Due to limited high temperature formability, a copper extrusion will not yield the same detail as aluminum. Also, machining copper takes more time and wears cutters at a much higher rate. However, when an application is limited in conduction, copper is a commonly used alternative.
Forced convection from a fan is out of consideration as it would interfere with the measurement. Liquid cooling is difficult to implement.
This magnetron for example, requires water cooling:
http://www.ok1rr.com/tubes/burle/s94608e.pdf
Liquid Cooling:
Tube anode requires liquid cooling Liquid flow must start
before application of filament voltage and, preferably,
continue for several minutes after removing voltage.
Interlock filament power supply with liquid flow to prevent
tube damage due to inadequate liquid flow. When liquid is
water, use of distilled or filtered deionized water is
essential.
Water Flow .... (15 kW anode dissipation) 20.4 I/min. (5.5 gpm)
It is a 0.95GHz magnetron though (instead of 2.45GHz)
A 0.915 GHz magnetron would have some benefits: the frustum would be slightly bigger to built, but the tolerance to achieve and maintain resonance would be easier than on a smaller frustum.
But at such a cost (how much?) I wonder why the labs do not plan to use a much cleaner source of microwaves instead, like a klystron, which offers both high power and narrow band.
Magnetrons are ok because they are compact and that the 2.45 GHz models from ovens are really cheap. But with enough $$$ and other frequencies investigated, I think TWTAs and klystrons would do a better job.
Thought is that the time constants are associated more with the PLR and time it takes for the magnetron/frustrum to reach resonance as opposed to the "EM-Drive/Q-Thruster" phenomena (if real). If we are seeing Conservation of Momentum than this should occur basically at the speed of light. At 5MW with an industrial magnetron transmitter we will achieve resonance for sure within the 10us, and will demonstrate that by first measuring Q prior to attempting any measurement of thrust. Concern however is if Conservation of Momentum depends on "fluidization of the quantum vacuum"; again, does this occur at the speed of light or do we require cycles and if so, how many? The follow up 100kW continuous trial will then follow, just working on the frustrum cooling system (nitrogen).Ironically there is a unit set up to do 5MW pulses that can adjust frequency within 10MHz of 930MHz ( frustum dimensions would not have to be exact that we could find resonance). At 10 microseconds the cooling of the frustum is managable without online cooling. Issue is would you see something in 10microseconds? Such a test hopefully could produce results that are an order of magnitude above background (into the ground no buoyant effects) or allow other phenomena (photon thruster leakage?) to be measurable. This will probably be experiment one as it is relatively cheap. If it's CoM I expect to see something on a digital scale within those 10us.
It's the duty cycle that matters in this case. If the 10 uS pulse happens once a Sec. you have a duty cycle of .001% and a time averaged power of 50 Watts, which is close to the power level the NASA team used. Because the mass you are trying to move is so much larger you would see less EM-Drive thrust (if it really exists) but you would also get more thermal, magnetic, and electrostatic effects. All of the EM-Drive "thrust" signatures disclosed so far have large time constants. So the effect of each individual 5 MW pulse would not be observable. This is just my opinion. I haven't done any EM-Drive experiments. I have been told I will soon be eating my words. I am still waiting...
My intention is to simulate a real loop using phase matched dipoles or point sources, ignoring the mechanics of implementation. I think that is best because Shell can then approximate the real loop to the best of her ability. Hopefully the simulation and implementation will converge toward the same end result. But I need to go off and do that now.
aero
Do have a dumb question regarding thermal lift. Even if the magnetron is removed from the frustum assembly, it will generate heat around it's tube, thereby creating lift. If it is mechanically attached to the frustum, wouldn't the lift be simply recentered?
There will be less conductive heating of the frustum, depending on how far away and the interconnects used, but the maggy itself will remain hot, regardless...
Yes, that's essentially correct. The magnetron is what gets hottest. As long as the magnetron is mechanically attached to the fustrum, the lift created by the natural thermal convection currents from the magnetron will carry the frustum with it, so having the magnetron attached to a waveguide doesn't seem to improve things since it makes everything heavier (bad) and there is no improvement because the magnetron is still mechanically attached.
A possible improvement is to provide more and better heat sink to the magnetron.
Pure aluminum has a conductivity of 230 W/m-K. Copper is better: 390 W/m-K which means a 70% increase in conduction over aluminum. That’s the good news. The down side of copper is that it weighs three times more than aluminum, costs the same on a per pound basis and is more difficult to machine. Due to limited high temperature formability, a copper extrusion will not yield the same detail as aluminum. Also, machining copper takes more time and wears cutters at a much higher rate. However, when an application is limited in conduction, copper is a commonly used alternative.
Forced convection from a fan is out of consideration as it would interfere with the measurement. Liquid cooling is difficult to implement.
This magnetron for example, requires water cooling:
http://www.ok1rr.com/tubes/burle/s94608e.pdf
Liquid Cooling:
Tube anode requires liquid cooling Liquid flow must start
before application of filament voltage and, preferably,
continue for several minutes after removing voltage.
Interlock filament power supply with liquid flow to prevent
tube damage due to inadequate liquid flow. When liquid is
water, use of distilled or filtered deionized water is
essential.
Water Flow .... (15 kW anode dissipation) 20.4 I/min. (5.5 gpm)
It is a 0.95GHz magnetron though (instead of 2.45GHz)
@rfmwguyYes, I'm about to steal my wife's Cuisinart Grille and put underneath the frustum...Oh-oh...now I've done it...she reads my posts sometimes. :o
You could use a electrical heat source close to the magnetron position in your setup, and than look what the laserpoint does while a blind test... :)
My intention is to simulate a real loop using phase matched dipoles or point sources, ignoring the mechanics of implementation. I think that is best because Shell can then approximate the real loop to the best of her ability. Hopefully the simulation and implementation will converge toward the same end result. But I need to go off and do that now.
aero
I don't see how multiple dipoles arranged in a circle simulates a loop, unless you're trying to implement a very high harmonic in the azimuthal direction. For TE012, there are only 2 poles around the circle.
Why is it difficult to simulate current through a piece of wire, fed by a current source?
Todd
,,,I don't see how multiple dipoles arranged in a circle simulates a loop, unless you're trying to implement a very high harmonic in the azimuthal direction....
...
...For TE012, there are only 2 poles around the circle...That's incorrect.
Maybe remove the water in the air?Do have a dumb question regarding thermal lift. Even if the magnetron is removed from the frustum assembly, it will generate heat around it's tube, thereby creating lift. If it is mechanically attached to the frustum, wouldn't the lift be simply recentered?
There will be less conductive heating of the frustum, depending on how far away and the interconnects used, but the maggy itself will remain hot, regardless...
Yes, that's essentially correct. The magnetron is what gets hottest. As long as the magnetron is mechanically attached to the fustrum, the lift created by the natural thermal convection currents from the magnetron will carry the frustum with it, so having the magnetron attached to a waveguide doesn't seem to improve things since it makes everything heavier (bad) and there is no improvement because the magnetron is still mechanically attached.
A possible improvement is to provide more and better heat sink to the magnetron.
Pure aluminum has a conductivity of 230 W/m-K. Copper is better: 390 W/m-K which means a 70% increase in conduction over aluminum. That’s the good news. The down side of copper is that it weighs three times more than aluminum, costs the same on a per pound basis and is more difficult to machine. Due to limited high temperature formability, a copper extrusion will not yield the same detail as aluminum. Also, machining copper takes more time and wears cutters at a much higher rate. However, when an application is limited in conduction, copper is a commonly used alternative.
Forced convection from a fan is out of consideration as it would interfere with the measurement. Liquid cooling is difficult to implement.
This magnetron for example, requires water cooling:
http://www.ok1rr.com/tubes/burle/s94608e.pdf
Liquid Cooling:
Tube anode requires liquid cooling Liquid flow must start
before application of filament voltage and, preferably,
continue for several minutes after removing voltage.
Interlock filament power supply with liquid flow to prevent
tube damage due to inadequate liquid flow. When liquid is
water, use of distilled or filtered deionized water is
essential.
Water Flow .... (15 kW anode dissipation) 20.4 I/min. (5.5 gpm)
It is a 0.95GHz magnetron though (instead of 2.45GHz)
I think it's not just the temperature of the Magentron that is heating the air, but also the microwaves heating the water vapor in the air. So simply removing the heat caused by the hot metals is only half the problem. I think it would be easier to remove the air. :)
Todd
I'm going to give you a piece or rope attached at one end to a plate 6 foot long. Your job if you should decide to accept Mr. Todd is to make the rope oscillate harmonically in a sustained wave pattern. Easy? Right. Any school kid will tell you that it is that has ever watched someone jumping rope. Now I going to put that rope in a cone shaped cavity where the osculating peaks of the waves hit the side walls of the cone shape. Your job is to find not only a standing wave up and down the rope length that is the same peak to peak but a particular one, at a particular frequency and rotating just so.My intention is to simulate a real loop using phase matched dipoles or point sources, ignoring the mechanics of implementation. I think that is best because Shell can then approximate the real loop to the best of her ability. Hopefully the simulation and implementation will converge toward the same end result. But I need to go off and do that now.
aero
I don't see how multiple dipoles arranged in a circle simulates a loop, unless you're trying to implement a very high harmonic in the azimuthal direction. For TE012, there are only 2 poles around the circle.
Why is it difficult to simulate current through a piece of wire, fed by a current source?
Todd
Yes, this fall and winter will be much better. All tests done had RH about 50-59%, which is common this time of the year. Funny though, I've never measure much of a heat rise on the frustum side or plate opposite magnetron just after a test. The mesh should dissipate heated air quickly.Maybe remove the water in the air?Do have a dumb question regarding thermal lift. Even if the magnetron is removed from the frustum assembly, it will generate heat around it's tube, thereby creating lift. If it is mechanically attached to the frustum, wouldn't the lift be simply recentered?
There will be less conductive heating of the frustum, depending on how far away and the interconnects used, but the maggy itself will remain hot, regardless...
Yes, that's essentially correct. The magnetron is what gets hottest. As long as the magnetron is mechanically attached to the fustrum, the lift created by the natural thermal convection currents from the magnetron will carry the frustum with it, so having the magnetron attached to a waveguide doesn't seem to improve things since it makes everything heavier (bad) and there is no improvement because the magnetron is still mechanically attached.
A possible improvement is to provide more and better heat sink to the magnetron.
Pure aluminum has a conductivity of 230 W/m-K. Copper is better: 390 W/m-K which means a 70% increase in conduction over aluminum. That’s the good news. The down side of copper is that it weighs three times more than aluminum, costs the same on a per pound basis and is more difficult to machine. Due to limited high temperature formability, a copper extrusion will not yield the same detail as aluminum. Also, machining copper takes more time and wears cutters at a much higher rate. However, when an application is limited in conduction, copper is a commonly used alternative.
Forced convection from a fan is out of consideration as it would interfere with the measurement. Liquid cooling is difficult to implement.
This magnetron for example, requires water cooling:
http://www.ok1rr.com/tubes/burle/s94608e.pdf
Liquid Cooling:
Tube anode requires liquid cooling Liquid flow must start
before application of filament voltage and, preferably,
continue for several minutes after removing voltage.
Interlock filament power supply with liquid flow to prevent
tube damage due to inadequate liquid flow. When liquid is
water, use of distilled or filtered deionized water is
essential.
Water Flow .... (15 kW anode dissipation) 20.4 I/min. (5.5 gpm)
It is a 0.95GHz magnetron though (instead of 2.45GHz)
I think it's not just the temperature of the Magentron that is heating the air, but also the microwaves heating the water vapor in the air. So simply removing the heat caused by the hot metals is only half the problem. I think it would be easier to remove the air. :)
Todd
I'm going to give you a piece or rope attached at one end to a plate 6 foot long. Your job if you should decide to accept Mr. Todd is to make the rope oscillate harmonically in a sustained wave pattern. Easy? Right. Any school kid will tell you that it is that has ever watched someone jumping rope. Now I going to put that rope in a cone shaped cavity where the osculating peaks of the waves hit the side walls of the cone shape. Your job is to find not only a standing wave up and down the rope length that is the same peak to peak but a particular one, at a particular frequency and rotating just so.My intention is to simulate a real loop using phase matched dipoles or point sources, ignoring the mechanics of implementation. I think that is best because Shell can then approximate the real loop to the best of her ability. Hopefully the simulation and implementation will converge toward the same end result. But I need to go off and do that now.
aero
I don't see how multiple dipoles arranged in a circle simulates a loop, unless you're trying to implement a very high harmonic in the azimuthal direction. For TE012, there are only 2 poles around the circle.
Why is it difficult to simulate current through a piece of wire, fed by a current source?
Todd
No, it's not that simple.
DailyKos...last place I thought I'd get some emdrive press :o
http://www.dailykos.com/story/2015/08/26/1415532/-EmDrive-Jesus-What-a-Day#
My intention is to simulate a real loop using phase matched dipoles or point sources, ignoring the mechanics of implementation. I think that is best because Shell can then approximate the real loop to the best of her ability. Hopefully the simulation and implementation will converge toward the same end result. But I need to go off and do that now.
aero
I don't see how multiple dipoles arranged in a circle simulates a loop, unless you're trying to implement a very high harmonic in the azimuthal direction. For TE012, there are only 2 poles around the circle.
Why is it difficult to simulate current through a piece of wire, fed by a current source?
Todd
Yes, we all knew from the beginning that the best thing is to use a circular loop and that was the starting recommendation, but he doesn't know how to input a circular loop in Meep, only knows how to input straight dipole antennas.
It is not a problem of modellling the behavior of the antenna.My intention is to simulate a real loop using phase matched dipoles or point sources, ignoring the mechanics of implementation. I think that is best because Shell can then approximate the real loop to the best of her ability. Hopefully the simulation and implementation will converge toward the same end result. But I need to go off and do that now.
aero
I don't see how multiple dipoles arranged in a circle simulates a loop, unless you're trying to implement a very high harmonic in the azimuthal direction. For TE012, there are only 2 poles around the circle.
Why is it difficult to simulate current through a piece of wire, fed by a current source?
Todd
Yes, we all knew from the beginning that the best thing is to use a circular loop and that was the starting recommendation, but he doesn't know how to input a circular loop in Meep, only knows how to input straight dipole antennas.
So can any of the available antenna design software output an antenna into a format MEEP likes? http://www.arrl.org/antenna-modeling (http://www.arrl.org/antenna-modeling)
My intention is to simulate a real loop using phase matched dipoles or point sources, ignoring the mechanics of implementation. I think that is best because Shell can then approximate the real loop to the best of her ability. Hopefully the simulation and implementation will converge toward the same end result. But I need to go off and do that now.
aero
I don't see how multiple dipoles arranged in a circle simulates a loop, unless you're trying to implement a very high harmonic in the azimuthal direction. For TE012, there are only 2 poles around the circle.
Why is it difficult to simulate current through a piece of wire, fed by a current source?
Todd
Indeed. But bear in mind that both the spring and the pivot counterbalance solution potentially introduce extra stiction.I think rfmwguy is seeing stiction from someplace else other than the knife edge, maybe from his liquid conductor? I would take it out of the loop (take out the copper wires) and see what amount of stiction he is then seeing.
Personal preference I went with a rolling knife edge and haven't even been able to measure any stiction and my scales are set to .01 gram.
Agate is a tough material and is harder than steel. With a large balance arm the knife edge could be a replacement blade for a jointer and the agate plane could be a quartz flat.
In the Mohs Hardness Scale Agate can have a hardness of 6 to 7 Mohs, while steels can have a Mohs hardness from 5 to 8.5.
The word ``stiction'' was coined at IBM General Products Division labs in San Jose, CA around 1980 when they encountered that head slider getting stuck to the disk surface while resting at high humidities due to liquid mediated adhesion. High lateral force had to be applied to initiate sliding to overcome high static friction or sticking, hence leading to the term stiction. This is not at all the contact issue of in the knife edge contact problem in RFMWGUY's experiment. Rather, the problem is due to the well known issue of plastic deformation at the nano-scale roughness of contact, with the material nano-contact stresses exceeding the yield stress of the metals involved in contact. It is not due to liquid mediated adhesion. On the contrary, it is a dry contact problem.Wow! was that a flash back!
Strictly speaking it is incorrect to use the term "stiction" to the contact of two knife edges as being used in RFMWGUY's experiment or to use the word stiction for the contact issues associated with a knife-edge balance. The article on stiction in Wikipedia (like many articles in Wikipedia) lacks scholarship.
A couple of peer-reviewed articles (there are literally hundreds of articles, and dozens of books on Tribology showing this known fact) clarifying the benefits of lubrication in contact problems:
http://jbyoon0901.cafe24.com/wp-content/uploads/2013/05/APL_2011_An-insulating-liquid-environment-for-reducing-adhesion-in-a-microelectromechanicalsystem.pdf?ckattempt=1
http://masters.dgtu.donetsk.ua/2014/fimm/mitina/library/article11.pdf
----------
PS: Agate is not at all a tough material when compared to steel, and when using a scientific measure of toughness. Agate is a crystalline variety of silica, found in nature, in volcanic rocks and certain metamorphic rocks, as such it is technically a ceramic material. It lacks the toughness ductility like steel, agate has a lower Fracture Toughness (measured as G1c) than steel. As to "hardness", hardness is not a scientific measure, there are different ways to measure "hardness" as they mix different scientific measures together like the yield strength, and stiffness together. In the Mohs Hardness Scale Agate can have a hardness of 6 to 7 Mohs, while steels can have a Mohs hardness from 5 to 8.5.
...Wow! was that a flash back!...It's fascinating how the lives of different people in this thread are intertwined in disparate fields, and we are all here discussing experiments and analysis of a seemingly impossible space propulsion :)
Agate is a tough material and is harder than steel. With a large balance arm the knife edge could be a replacement blade for a jointer and the agate plane could be a quartz flat.
I am not sure but I heard that Iphone 6 use sapphire windows, in that case according to mohs scale it is a lot harder than quartz
The iPhone 6 doesn't use such a screen.
http://www.dailymail.co.uk/sciencetech/article-2758097/How-Apple-s-iPhone-6-ion-strengthened-screen-Expert-reveals-chemical-process-used-create-display.html
The iPhone 6 doesn't use such a screen.
Are you sure? I search a bit and found this:
Sapphire windows are used in Apple Touch ID of the iPhone 5s, iPhone 6, and iPad mini 3and the display of the Apple Watch. Also, sapphire covers are used for the rear camera in every iPhone 5 or newer.
https://en.wikipedia.org/wiki/Sapphire
Long shot here, but I was reading up on how squeezed light can be generated and I found that one way is via nonlinear frequency mixing. I think I saw evidence of frequency mixing a few months ago by accident. Guess I pretty much have to bust out the test equipment again now to confirm.
http://physics.stackexchange.com/questions/83/how-is-squeezed-light-produced
https://en.wikipedia.org/wiki/Nonlinear_optics#Nonlinear_optical_processes
Anyway, there's some literature out there about using squeezed vacuum for propulsion which is interesting.
http://www.researchgate.net/publication/258317790_Preliminary_Theorectical_Considerations_for_Getting_Thrust_via_Squeezed_Vacuum
http://www.researchgate.net/publication/234887561_Extraction_of_Thrust_from_Quantum_Vacuum_Using_Squeezed_Light
But the failure to replicate is not a cause for alarm; in fact, it is a normal part of how science works.
Suppose you have two well-designed, carefully run studies, A and B, that investigate the same phenomenon. They perform what appear to be identical experiments, and yet they reach opposite conclusions. Study A produces the predicted phenomenon, whereas Study B does not. We have a failure to replicate.
Does this mean that the phenomenon in question is necessarily illusory? Absolutely not. If the studies were well designed and executed, it is more likely that the phenomenon from Study A is true only under certain conditions. The scientist’s job now is to figure out what those conditions are, in order to form new and better hypotheses to test.
NSF-1701 New Video - Static test of assembly today without electrodes in galinstan, which adds dampening and drag. When the galinstan was removed, there were wild movements of laser spot, as I noted when I first designed the test stand. Therefore I re-attached Doc's oil dampener, which greatly reduced vertical meanderings. The oil dampener addition and galinstan removal provided a laser spot displacement on the target of approximately the same amount. IOW, galinstan and no oil dampener and 500 mg weight added approximately equal no galinstan and oil dampener and 200 mg weight added. So, the drag/viscosity of galinstan is equal to about 300 mg...far more than I imagined.
Here's the video for detailed analysis:
https://youtu.be/jvjrJK90iYM
Doc, this test was 0, 200, 0 and 100 mg. No power applied.NSF-1701 New Video - Static test of assembly today without electrodes in galinstan, which adds dampening and drag. When the galinstan was removed, there were wild movements of laser spot, as I noted when I first designed the test stand. Therefore I re-attached Doc's oil dampener, which greatly reduced vertical meanderings. The oil dampener addition and galinstan removal provided a laser spot displacement on the target of approximately the same amount. IOW, galinstan and no oil dampener and 500 mg weight added approximately equal no galinstan and oil dampener and 200 mg weight added. So, the drag/viscosity of galinstan is equal to about 300 mg...far more than I imagined.
Here's the video for detailed analysis:
https://youtu.be/jvjrJK90iYM
Excellent. By the way, let's not forget that you also verified the importance of air currents in the motion of the beam, upon removal of the Galistan damping action. There are still posters that question whether air currents are responsible for such motions. As I understand it, you tested by adding 500 mg weight, hence there is no electromagnetic force involved in this test.
NSF-1701 New Video - Static test of assembly today without electrodes in galinstan, which adds dampening and drag. When the galinstan was removed, there were wild movements of laser spot, as I noted when I first designed the test stand. Therefore I re-attached Doc's oil dampener, which greatly reduced vertical meanderings. The oil dampener addition and galinstan removal provided a laser spot displacement on the target of approximately the same amount. IOW, galinstan and no oil dampener and 500 mg weight added approximately equal no galinstan and oil dampener and 200 mg weight added. So, the drag/viscosity of galinstan is equal to about 300 mg...far more than I imagined.
Here's the video for detailed analysis:
https://youtu.be/jvjrJK90iYM
Long shot here, but I was reading up on how squeezed light can be generated and I found that one way is via nonlinear frequency mixing. I think I saw evidence of frequency mixing a few months ago by accident. Guess I pretty much have to bust out the test equipment again now to confirm.
http://physics.stackexchange.com/questions/83/how-is-squeezed-light-produced
https://en.wikipedia.org/wiki/Nonlinear_optics#Nonlinear_optical_processes
Anyway, there's some literature out there about using squeezed vacuum for propulsion which is interesting.
http://www.researchgate.net/publication/258317790_Preliminary_Theorectical_Considerations_for_Getting_Thrust_via_Squeezed_Vacuum
http://www.researchgate.net/publication/234887561_Extraction_of_Thrust_from_Quantum_Vacuum_Using_Squeezed_Light
I find this rather interesting since I just found the following on my facebook feed claiming proof that squeezed light is real.
http://www.cam.ac.uk/research/news/scientists-squeeze-light-one-particle-at-a-time
That said if this is going to be an avenue used to prove thrust from the EmDrive then alot of work would need to go into to explaining how the frustum is squeezing light at what seems to be lower power levels and in a radically different environment.
The iPhone 6 doesn't use such a screen.
Are you sure? I search a bit and found this:
Sapphire windows are used in Apple Touch ID of the iPhone 5s, iPhone 6, and iPad mini 3and the display of the Apple Watch. Also, sapphire covers are used for the rear camera in every iPhone 5 or newer.
https://en.wikipedia.org/wiki/Sapphire
Do have a dumb question regarding thermal lift. Even if the magnetron is removed from the frustum assembly, it will generate heat around it's tube, thereby creating lift. If it is mechanically attached to the frustum, wouldn't the lift be simply recentered?
There will be less conductive heating of the frustum, depending on how far away and the interconnects used, but the maggy itself will remain hot, regardless...
Yes, that's essentially correct. The magnetron is what gets hottest. As long as the magnetron is mechanically attached to the fustrum, the lift created by the natural thermal convection currents from the magnetron will carry the frustum with it, so having the magnetron attached to a waveguide doesn't seem to improve things since it makes everything heavier (bad) and there is no improvement because the magnetron is still mechanically attached.
A possible improvement is to provide more and better heat sink to the magnetron.
Pure aluminum has a conductivity of 230 W/m-K. Copper is better: 390 W/m-K which means a 70% increase in conduction over aluminum. That’s the good news. The down side of copper is that it weighs three times more than aluminum, costs the same on a per pound basis and is more difficult to machine. Due to limited high temperature formability, a copper extrusion will not yield the same detail as aluminum. Also, machining copper takes more time and wears cutters at a much higher rate. However, when an application is limited in conduction, copper is a commonly used alternative.
Forced convection from a fan is out of consideration as it would interfere with the measurement. Liquid cooling is difficult to implement.
This magnetron for example, requires water cooling:
http://www.ok1rr.com/tubes/burle/s94608e.pdf
Liquid Cooling:
Tube anode requires liquid cooling Liquid flow must start
before application of filament voltage and, preferably,
continue for several minutes after removing voltage.
Interlock filament power supply with liquid flow to prevent
tube damage due to inadequate liquid flow. When liquid is
water, use of distilled or filtered deionized water is
essential.
Water Flow .... (15 kW anode dissipation) 20.4 I/min. (5.5 gpm)
It is a 0.95GHz magnetron though (instead of 2.45GHz)
A 0.915 GHz magnetron would have some benefits: the frustum would be slightly bigger to built, but the tolerance to achieve and maintain resonance would be easier than on a smaller frustum.
But at such a cost (how much?) for very high power, say a hundred to thousands of kilowatts, I wonder why those labs (like CraigPichach's university (http://forum.nasaspaceflight.com/index.php?topic=38203.msg1420716#msg1420716)) do not plan to use a much cleaner source of microwaves instead, like a klystron, which offers both high power and narrow band.
Magnetrons are ok because they are compact and that the 2.45 GHz models from ovens are really cheap. But with enough $$$ and other frequencies investigated, I think TWTAs and klystrons would do a better job.
EDIT: Whatever I'd love to see an experiment with an N2-cooled frustum powered by a 100kW-class liquid-cooled magnetron! This would be waaaay beyond what we saw even from Shawyer. :)
My intention is to simulate a real loop using phase matched dipoles or point sources, ignoring the mechanics of implementation. I think that is best because Shell can then approximate the real loop to the best of her ability. Hopefully the simulation and implementation will converge toward the same end result. But I need to go off and do that now.
aero
I don't see how multiple dipoles arranged in a circle simulates a loop, unless you're trying to implement a very high harmonic in the azimuthal direction. For TE012, there are only 2 poles around the circle.
Why is it difficult to simulate current through a piece of wire, fed by a current source?
Todd
I'm not certain that it will work but I think its worth a try. I know this code:
(define stubsideleft (list
(make source (src (make gaussian-src (frequency fmeep) (fwidth BW) ))
(component Ex)
(center (- 0 bxant) byant bzant)
(size bantsizex bantsizey antsizez)
(amplitude (exp (* 0+1i pi)))
(axis axex axey axez) )
))
Specifically the line, (amplitude (exp (* 0+1i pi))), shifts the phase of the antenna RF by pi or 180 degrees. I also know I can write a software loop in Scheme. I also know where the center of each dipole or point source is so it seems that the phase of each source should depend on the phase of and distance from the previous source around the antenna loop. Thing I'm not certain about is if the time-stepping in meep will mess with the phasing. I'm working with the assumption that it will not as meep must surly maintain proper source phasing from one time-step to the next. Without doing so, meep couldn't propagate RF waves.
Now, if anyone wants to give me the math for transforming points on the antenna loop circumference to cartesian x, y, z, I would be pleased to check it against mine. Might well save me considerable time. Or maybe meep supplies such coordinate transformation functions that I just haven't needed to look into. (It just occurred to me to look.) And just exactly how much is the phase shift from one point to the next. The arc distance divided by the wavelength? Actually, I guess it would be negative of that as phase increases with time.
The iPhone 6 doesn't use such a screen.
Are you sure? I search a bit and found this:
Sapphire windows are used in Apple Touch ID of the iPhone 5s, iPhone 6, and iPad mini 3and the display of the Apple Watch. Also, sapphire covers are used for the rear camera in every iPhone 5 or newer.
https://en.wikipedia.org/wiki/Sapphire
I'm not certain that it will work but I think its worth a try. I know this code:
(define stubsideleft (list
(make source (src (make gaussian-src (frequency fmeep) (fwidth BW) ))
(component Ex)
(center (- 0 bxant) byant bzant)
(size bantsizex bantsizey antsizez)
(amplitude (exp (* 0+1i pi)))
(axis axex axey axez) )
))
Specifically the line, (amplitude (exp (* 0+1i pi))), shifts the phase of the antenna RF by pi or 180 degrees. I also know I can write a software loop in Scheme. I also know where the center of each dipole or point source is so it seems that the phase of each source should depend on the phase of and distance from the previous source around the antenna loop. Thing I'm not certain about is if the time-stepping in meep will mess with the phasing. I'm working with the assumption that it will not as meep must surly maintain proper source phasing from one time-step to the next. Without doing so, meep couldn't propagate RF waves.
Now, if anyone wants to give me the math for transforming points on the antenna loop circumference to cartesian x, y, z, I would be pleased to check it against mine. Might well save me considerable time. Or maybe meep supplies such coordinate transformation functions that I just haven't needed to look into. (It just occurred to me to look.) And just exactly how much is the phase shift from one point to the next. The arc distance divided by the wavelength? Actually, I guess it would be negative of that as phase increases with time.
That's why I think this is the way to go - an experiment above background.More power is not necessarily a panacea. It may be that thermal artifacts scale as fast, or faster than does any signal.
I'm not certain that it will work but I think its worth a try. I know this code:
(define stubsideleft (list
(make source (src (make gaussian-src (frequency fmeep) (fwidth BW) ))
(component Ex)
(center (- 0 bxant) byant bzant)
(size bantsizex bantsizey antsizez)
(amplitude (exp (* 0+1i pi)))
(axis axex axey axez) )
))
Specifically the line, (amplitude (exp (* 0+1i pi))), shifts the phase of the antenna RF by pi or 180 degrees. I also know I can write a software loop in Scheme. I also know where the center of each dipole or point source is so it seems that the phase of each source should depend on the phase of and distance from the previous source around the antenna loop. Thing I'm not certain about is if the time-stepping in meep will mess with the phasing. I'm working with the assumption that it will not as meep must surly maintain proper source phasing from one time-step to the next. Without doing so, meep couldn't propagate RF waves.
Now, if anyone wants to give me the math for transforming points on the antenna loop circumference to cartesian x, y, z, I would be pleased to check it against mine. Might well save me considerable time. Or maybe meep supplies such coordinate transformation functions that I just haven't needed to look into. (It just occurred to me to look.) And just exactly how much is the phase shift from one point to the next. The arc distance divided by the wavelength? Actually, I guess it would be negative of that as phase increases with time.
in pseudo code:
divisions = 10
radius = 1
angle = 2*pi/divisions
for (n =0; n< divisions; n++)
a = angle*n
x = cos(a)*radius
y = sin(a)*radius
amplitude = exp((0+1i)*a)
make_new_source(x, y, amplitude)
Angles in radians. Amplitude is based on "(amplitude (exp (* 0+1i pi)))" - when the source is 180 degrees from the first source, the amplitude is exp((0+1i)*pi).
Is that what you were looking for?
Specify the direction and type of the current component: e.g. Ex, Ey, etcetera for an electric-charge current, and Hx, Hy, etcetera for a magnetic-charge current. Note that currents pointing in an arbitrary direction are specified simply as multiple current sources with the appropriate amplitudes for each component. No default.The boldfaced (added) sentence is the detail.
That's why I think this is the way to go - an experiment above background.More power is not necessarily a panacea. It may be that thermal artifacts scale as fast, or faster than does any signal.
(set! mag (sqrt (+ (* dx dx) (* dy dy) (* dz dz))))
(set! emmagx (* mag dx))
(set! emmagy (* mag dy)) ; check this, really want emmag normalized to 1
(set! emmagz (* mag dz))
(make source (src (make continuous-src (frequency mple_f))); (fwidth df)))
(component Hz)
(center rx ry rz)
(size dx dy dz)
(amplitude (exp (* 0+1i pfase)))
(axis 0 0 1) )
So now I need to properly include the emmag into the amplitude without messing up the phasing. In other words, I think it is a real term multiplication of a complex number. Leaning toward
(amplitude (* emmag (exp (* 0+1i pfase))))
but of course that won't work because of the real 0 in the complex frequency. All it will do is mess with the phase.
The assumption that thermal effects are unidirectional isn't necessarily so. Take, for example, shifts in the centre of gravity when using a balance. Or gas jets which have an upwards component.
(set! mag (sqrt (+ (* dx dx) (* dy dy) (* dz dz))))
(set! emmagx (* mag dx))
(set! emmagy (* mag dy)) ; check this, really want emmag normalized to 1
(set! emmagz (* mag dz))
I think you want to divide, not multiply, e.g. " (set! emmagx (/ dx mag)) ". If you do that, sqrt(emmagx^2 + emmagy^2 + emmagz^2) = 1.(make source (src (make continuous-src (frequency mple_f))); (fwidth df)))
(component Hz)
(center rx ry rz)
(size dx dy dz)
(amplitude (exp (* 0+1i pfase)))
(axis 0 0 1) )
So now I need to properly include the emmag into the amplitude without messing up the phasing. In other words, I think it is a real term multiplication of a complex number. Leaning toward
(amplitude (* emmag (exp (* 0+1i pfase))))
but of course that won't work because of the real 0 in the complex frequency. All it will do is mess with the phase.
I don't know what you're getting at here. If "emmag" is the magnitude and it's normalized to 1, what's the point of multiplying it with anything?
I feel like I'm missing something.
Specify the direction and type of the current component: e.g. Ex, Ey, etcetera for an electric-charge current, and Hx, Hy, etcetera for a magnetic-charge current. Note that currents pointing in an arbitrary direction are specified simply as multiple current sources with the appropriate amplitudes for each component.Does that mean I actually need to use (for electric-charge current) Ex, Ey and Ez components for the dx, dy and dz component directions of the dipole? That doesn't seem right. Or do I need to use 9 weighted sources, 3 each for Ex, Ey, and Ez. Or are those two choices really the same thing?
Yes, we do tend to fantasise about the mythical hole in the ceiling
I am beginning to understand how we must plan for thermal errors. Elsewhere, it was posted that the south african experiment measured upwards thrust. I find this a questionable test method as I've seen the results of thermal lift personally. Will continue to focus on downward movement only. Think I will set up a test for establishing max thermal lift point and then look for downward movement from there. As I continue tweaking the setup, I am becoming more critical...guess that's the way its supposed to be.That's why I think this is the way to go - an experiment above background.More power is not necessarily a panacea. It may be that thermal artifacts scale as fast, or faster than does any signal.
These modern analytical beams are capable of measuring down with confidence amounts being transferred to a precision of one tenth of a milligram or one ten-thousandth of a gram, ±0.0001 g. but are limited to 160-200 gram capacity ranges.The Mettler H10 will get you 10 ug, and it's about 50 years old. When it was introduced, it revolutionised chemistry labs' technique.
Suggestion for today:Great info!
We would also go so far as to put a machined solid 1” steel plate underneath the Balance say 20kgs when it was sitting on a bench [you would see movement of someone walking on the floor a metre away]
refine... refine ...refine....
Id love to use a mettler, but I think the laser displacement sensor will suffice. It fires off to 40 mm +/- 10 mm and should get into micrometer range resolution. Have to study specs but think sample rate is 10 msec. Longer term project will be to connect to latop running labview. Think I'll set up to show displacement as a chart or o-scope display. Other sensors can be added, mainly environmentals. Be nice to standardize on a common display that others can use to run tests. Temp and humidity could be inputs as well as seismic reference if we wanted to get fancy. Funny other higher profile labs haven't done this...if I could, so should others with much more time and money.These modern analytical beams are capable of measuring down with confidence amounts being transferred to a precision of one tenth of a milligram or one ten-thousandth of a gram, ±0.0001 g. but are limited to 160-200 gram capacity ranges.The Mettler H10 will get you 10 ug, and it's about 50 years old. When it was introduced, it revolutionised chemistry labs' technique.
It's quite a lot of work to do that, and to get it right, but I have to applaud your thinking there.
It's quite a lot of work to do that, and to get it right, but I have to applaud your thinking there.
An other idea could be instead of building and calibrate a mockup, to replace it by a second identical EMDrive and to play with the important constant of time of the thermal effects:
1- We turn on the two EMThrusters installed on the two side of the balance.
2- We wait the thermal steady state of the system and mass balance it to have an equilibrium.
3- We turn off one of the EMTruster and with a thermal balance condition which should stay stable for a while, we measure the displacement of the balance.
Doc, this test was 0, 200, 0 and 100 mg. No power applied.NSF-1701 New Video - Static test of assembly today without electrodes in galinstan, which adds dampening and drag. When the galinstan was removed, there were wild movements of laser spot, as I noted when I first designed the test stand. Therefore I re-attached Doc's oil dampener, which greatly reduced vertical meanderings. The oil dampener addition and galinstan removal provided a laser spot displacement on the target of approximately the same amount. IOW, galinstan and no oil dampener and 500 mg weight added approximately equal no galinstan and oil dampener and 200 mg weight added. So, the drag/viscosity of galinstan is equal to about 300 mg...far more than I imagined.
Here's the video for detailed analysis:
https://youtu.be/jvjrJK90iYM
Excellent. By the way, let's not forget that you also verified the importance of air currents in the motion of the beam, upon removal of the Galistan damping action. There are still posters that question whether air currents are responsible for such motions. As I understand it, you tested by adding 500 mg weight, hence there is no electromagnetic force involved in this test.
That's a great idea.
Folks - sorry to go AWOL after volunteering to do something, but my father has been visiting for some days. He's 81 - he doesn't need much looking after, but he does spend his days wandering through my house and garden pointing out chores which need doing, and organizing me to do them straight away...
I said I would do fourier analysis on the beam movements of rfmwguy's first experiment if someone would post the time-series, which was very soon done.
Of course, I omitted to mention that I would need the magnetron on/off audio signal to make much progress. With that I can match up the magnetron signal to the filtered beam signal and see what it tells us.
The rough analysis so far doesn't say much beyond what can be seen by eye in the plots posted,
R.
Doc, this test was 0, 200, 0 and 100 mg. No power applied.NSF-1701 New Video - Static test of assembly today without electrodes in galinstan, which adds dampening and drag. When the galinstan was removed, there were wild movements of laser spot, as I noted when I first designed the test stand. Therefore I re-attached Doc's oil dampener, which greatly reduced vertical meanderings. The oil dampener addition and galinstan removal provided a laser spot displacement on the target of approximately the same amount. IOW, galinstan and no oil dampener and 500 mg weight added approximately equal no galinstan and oil dampener and 200 mg weight added. So, the drag/viscosity of galinstan is equal to about 300 mg...far more than I imagined.
Here's the video for detailed analysis:
https://youtu.be/jvjrJK90iYM
Excellent. By the way, let's not forget that you also verified the importance of air currents in the motion of the beam, upon removal of the Galistan damping action. There are still posters that question whether air currents are responsible for such motions. As I understand it, you tested by adding 500 mg weight, hence there is no electromagnetic force involved in this test.
Hi all,
I chopped it up at 1 fps. Not sure what happens around the 800 second mark. I put a grid on the montage just to make it easier to compare sections. The xls file with the tracking data is attached.
As I mentioned the first time I did this, imageJ has the origin of the image at the top left so that's why the upwards movement of the laser produces a drop in the graph. I quite like this since it means frustum down=plot down. Easy enough to flip if people find it confusing.
An idea to get rid of the thermal imbalance:
Why not to use on the other side of the balance a thermally and geometrically repesentative mockup of the EMDrive thruster system (frustum + magnetron) with the objective to reproduce and so to cancel most of the thermal perturbations effects. We could try, using electrical heaters and control thermistors, to reproduce on the mockup by a preliminary calibration, the same profil of temperatures experienced by the active device.
Thanks once again for the great ideas and analysis! Looks like I'll have to bite the bullet and reconfigure the power going to the maggy. I think Shell is doing this, but I'll run 3 twisted wires about 4 feet to the end of the balance beam. The power feed will be at the center of the fulcrum, where the liquid metal (or whatever aqueous solution I try) will not have such an effect on moment arm displacement. So, to summarize:It is a great place to throw those ideas against the wall, isn't it?
1) Power supply feed at near the pivot point of fulcrum.
2) Twisted supply wires to end of beam and maggy..
3) Try other conductive liquids.
4) Keep Doc's oil dampener in use but add vertical plate to retard horizontal oscillations.
5) LDS for micrometer level resolution down the road.
Your/my test setup is improving! All open-source collaboration...well done folks.
If you're still interested and need some numbers here is a file that you use to get the timing.
.......
Here's my new fulcrum design, what does everyone think? ::)
Here's my new fulcrum design, what does everyone think? ::)
Not sure, got me stumped.
Shell
Anyone here have experience using paraview (https://www.paraview.org) with meep data, perhaps using the xdmf tool (http://comments.gmane.org/gmane.comp.science.electromagnetism.meep.general/5041) to create xdmf wrapper file for the h5 meep files?
I've got it working, but am trying to figure out how to drive it ...
So, I've given this a lot of thought. While I don't want to detract from other's fund raising activitles, I've been asked if I accept donations. Until now, I have not. The reasons I decided to do so is the mounting personal expenses of this experiment being done correctly.
Laser Displacement Sensors, new wiring, software, etc are not cheap...so if you would like to help, you can. Do not feel obligated, but know that your help will go 100% to the "Citizen Scientist" project known as NSF-1701.
This is the only post I will make in this regard and I appreciate your efforts to date.
The link is simple, no splashy page: https://www.paypal.me/NSF1701
Cheers - and thanks in advance,
Dave
Anyone here have experience using paraview (https://www.paraview.org) with meep data, perhaps using the xdmf tool (http://comments.gmane.org/gmane.comp.science.electromagnetism.meep.general/5041) to create xdmf wrapper file for the h5 meep files?
I've got it working, but am trying to figure out how to drive it ...
I've had bad experience with it. Got it working but it's to much program for my machine, or for me, or for both. Anyway, no good luck with it and I've forgotten anything I may have learned.
Okay - I've made some progress with it. Shout if interest gets going again.
Back to the task you set me - how do I know if we have resonance with the dipole antennae placements as I've made them?
Ed
26 deg C in shop...heat wave continues...nope, not going there. On the bright side the LDS arrived today. New HV wire from mcmaster arrives tomorrow. New wiring to nsf-1701 from power box to follow. No rest for the weary ;)
I finally finished the loop antenna modeling exercise. Not sure if this is still useful but I will post here. Likely the patterns are the most useful part - as they should give some idea of what modes can be stimulated.Herman,
These models and results are made using a version of the NEC codes (specifically EZNEC). NEC antenna modeling is not perfect but if you stay within the constraints it can produce qualitatively useful results. As with all such models, quantitative results are highly dependent on many factors including geometry, signal quality, and many more. Hopefully these will be of use - particularly if the loops are in a spherical chicken in a vacuum.
I modeled three sizes of antenna 1/2, 1, and 2 wavelength circumference, at three different heights - 1/4, 1/2 and 1 wavelength. Also modeled each of these configurations for loops both parallel to and normal to their ground plane.
Sorry for how long this took - as some of you know I have been in the process of retiring and unfortunately this exercise mostly had to take place late in evening after all other boring but necessary stuff had been done. I am now free and hope to start detailed planning for my own DIY experiments soon.
Herman
Interesting process to make a wave guide by 3D printing:
http://ieeexplore.ieee.org/xpls/abs_all.jsp?arnumber=7217811&tag=1
Interesting process to make a wave guide by 3D printing:
http://ieeexplore.ieee.org/xpls/abs_all.jsp?arnumber=7217811&tag=1
I have comparable FDM (plastic extrusion style) machines and know where to get this kind of copper plating done. The largest machine I currently own will do 11" diameter and 14.75" tall. The bed is circular, so the largest square cross section I can build is about a 7.5" square - not quite big enough for the designs currently being constructed (the large bases are about 11.6" diameter) to be built in one piece...
But I've had the copper plating done for stuff at work and the work comes out beautiful.
I love this stuff as the dicing saws we designed were an X, Y, Z & T movement axis <1um accuracy as well. One issue I think they still would be having using servos or steppers and an encoder feedback system is accumulated step errors of an axis. Even high count encoders in a quadrature mode will show this. But maybe they got it corrected where they don't. It was one of our IPs we never disclosed not to have indexing and accumulative errors.Interesting process to make a wave guide by 3D printing:
http://ieeexplore.ieee.org/xpls/abs_all.jsp?arnumber=7217811&tag=1
I have comparable FDM (plastic extrusion style) machines and know where to get this kind of copper plating done. The largest machine I currently own will do 11" diameter and 14.75" tall. The bed is circular, so the largest square cross section I can build is about a 7.5" square - not quite big enough for the designs currently being constructed (the large bases are about 11.6" diameter) to be built in one piece...
But I've had the copper plating done for stuff at work and the work comes out beautiful.
Cee, I like the pattern! Very nice work. Herman, beautiful. I guess I need to take more time from building to doing and learning NEC modeling.I finally finished the loop antenna modeling exercise. I am now free and hope to start detailed planning for my own DIY experiments soon.Herman,
Herman
Here's a 4NEC2 file of a small loop, I ran cases for .36 inch dia and am posting the NASA 0.55 inch loop. They serve as an approximate starting point in free space, in a cavity the impedance will be reduced by the mirroring of the walls. Impedance is 133-j60 and SWR 3.28. You will have to rename the NEC file, replace dot with a period and delete txt. The images are bmp files, replace dot with a period and remove txt.
Interesting process to make a wave guide by 3D printing:
http://ieeexplore.ieee.org/xpls/abs_all.jsp?arnumber=7217811&tag=1
I have comparable FDM (plastic extrusion style) machines and know where to get this kind of copper plating done. The largest machine I currently own will do 11" diameter and 14.75" tall. The bed is circular, so the largest square cross section I can build is about a 7.5" square - not quite big enough for the designs currently being constructed (the large bases are about 11.6" diameter) to be built in one piece...
But I've had the copper plating done for stuff at work and the work comes out beautiful.
What about heating?
Most of those extrusion type filaments start to loose their structural rigidity around 80-90°C.
You're speaking about diameter and circular printbed... using a delta printer? By far the most Z accurate printer you can have... (have one myself and VERY satisfied with it)
What type of plastic did you use to copperplate? I did not try copper plating myself , but it sounds an interesting approach, compared to the copper filament printing, which uses a mix of copper particles and plastic instead....
Hi folks -
Attached is what I made of the posted data from Croppa et al on NSF1702 FT1.
If I'm getting the sign conventions right, it appears the beam is being deflected down, i.e. frustrum up, when the magnetron is running, and relaxes back when it is off. I would really love to see what happens with this experiment repeated with the original configuration reversed, with the frustrum pointing the other way and the magnetron back at the original end of the frustrum. That said, things have moved on...
I've had to apply enough guesswork to various timings that the analysis would need to be checked before drawing conclusions, but the chart is at least 'Quite Interesting'.
The data is 1000 frames from frame 1080 in the video listing. I needed 4 fps to make the total run last the same time in audio and video.
R.
Interesting process to make a wave guide by 3D printing:
http://ieeexplore.ieee.org/xpls/abs_all.jsp?arnumber=7217811&tag=1
I have comparable FDM (plastic extrusion style) machines and know where to get this kind of copper plating done. The largest machine I currently own will do 11" diameter and 14.75" tall. The bed is circular, so the largest square cross section I can build is about a 7.5" square - not quite big enough for the designs currently being constructed (the large bases are about 11.6" diameter) to be built in one piece...
But I've had the copper plating done for stuff at work and the work comes out beautiful.
What about heating?
Most of those extrusion type filaments start to loose their structural rigidity around 80-90°C.
You're speaking about diameter and circular printbed... using a delta printer? By far the most Z accurate printer you can have... (have one myself and VERY satisfied with it)
What type of plastic did you use to copperplate? I did not try copper plating myself , but it sounds an interesting approach, compared to the copper filament printing, which uses a mix of copper particles and plastic instead....
We actually copperplated a billiard ball, but I have also seen results from this company on SLA printed plastics.
Yes, I have a delta arm machine - a SeeMeCNC RoStock MAX V2. Love this machine! Fast, accurate, and reliable. I haven't tried to push the resolution limits yet - been too busy printing things for customers!
I have never done delamination testing over temperature - and never needed to know so I've not looked it up. But I'm SURE there's good info out there...
I am printing in carbon fiber impregnated PLA (from ProtoPasta), plain PLA, and ABS. Haven't tried any of the metal impregnated plastics yet, but they're on my list - I wonder how they'd transfer heat?
The most that the "EM Drive" believers can hold on to here is that:
1) The RFMWGUY EM Drive test is not resonating (effectively meaning a Q below 1,000) in the RFMWGUY experiments
and/or
2) Whatever "EM Drive thrust force" taking place pointing towards the small base is so small, so tiny, that it is completely overwhelmed by the thermal lift of the magnetron. This force would have to be as small as measured by Tajmar.
So, this experiment by RFMWGUY either:
a) it is not in resonance
or
b) it nullifies the reported claims of Shawyer and Yang if the RFMWGUY EM Drive is resonating with a high Q
Still would be useful for low level measurements to characterize the frustum design itself, like the conical angle that was so much under discussion, as well as some novel frustum related shapes that were discussed here.Interesting process to make a wave guide by 3D printing:
http://ieeexplore.ieee.org/xpls/abs_all.jsp?arnumber=7217811&tag=1
I have comparable FDM (plastic extrusion style) machines and know where to get this kind of copper plating done. The largest machine I currently own will do 11" diameter and 14.75" tall. The bed is circular, so the largest square cross section I can build is about a 7.5" square - not quite big enough for the designs currently being constructed (the large bases are about 11.6" diameter) to be built in one piece...
But I've had the copper plating done for stuff at work and the work comes out beautiful.
What about heating?
Most of those extrusion type filaments start to loose their structural rigidity around 80-90°C.
You're speaking about diameter and circular printbed... using a delta printer? By far the most Z accurate printer you can have... (have one myself and VERY satisfied with it)
What type of plastic did you use to copperplate? I did not try copper plating myself , but it sounds an interesting approach, compared to the copper filament printing, which uses a mix of copper particles and plastic instead....
We actually copperplated a billiard ball, but I have also seen results from this company on SLA printed plastics.
Yes, I have a delta arm machine - a SeeMeCNC RoStock MAX V2. Love this machine! Fast, accurate, and reliable. I haven't tried to push the resolution limits yet - been too busy printing things for customers!
I have never done delamination testing over temperature - and never needed to know so I've not looked it up. But I'm SURE there's good info out there...
I am printing in carbon fiber impregnated PLA (from ProtoPasta), plain PLA, and ABS. Haven't tried any of the metal impregnated plastics yet, but they're on my list - I wonder how they'd transfer heat?
All depends on what temperatures one has to expect when using a 700W+ microwave generator.
When I read that R.Shawyer has burned through his frustum coppersheet walls on a few occasions, i fear all those type of 3Dprint materials will not last long before collapsing or even start to burn...
I'm not keen on even trying it....as i'm pretty sure it will fail.
The only solution would to drastically lower the power input. Question is then, will we then ever see any results from those low energy inputs? (keeping the baby-frustum in mind)
I think overall internal temperature should not exceed 70-80°C to use a copper plated filament 3Dprinted frustum...I'll have a heat conductivity test on the copper filament. Was going to test it anyway... :)
If you're going to 3D print it why not treat it like a paper cup of water that is set on the fire that never burns? Not a good scientific a analogy but gets the point across. Make the internal sidewalls of the frustum a spiral cavity that you can insert chilled water through. Like this quick idea sketch that shows the outer and inner skin cut away.Still would be useful for low level measurements to characterize the frustum design itself, like the conical angle that was so much under discussion, as well as some novel frustum related shapes that were discussed here.Interesting process to make a wave guide by 3D printing:
http://ieeexplore.ieee.org/xpls/abs_all.jsp?arnumber=7217811&tag=1
I have comparable FDM (plastic extrusion style) machines and know where to get this kind of copper plating done. The largest machine I currently own will do 11" diameter and 14.75" tall. The bed is circular, so the largest square cross section I can build is about a 7.5" square - not quite big enough for the designs currently being constructed (the large bases are about 11.6" diameter) to be built in one piece...
But I've had the copper plating done for stuff at work and the work comes out beautiful.
What about heating?
Most of those extrusion type filaments start to loose their structural rigidity around 80-90°C.
You're speaking about diameter and circular printbed... using a delta printer? By far the most Z accurate printer you can have... (have one myself and VERY satisfied with it)
What type of plastic did you use to copperplate? I did not try copper plating myself , but it sounds an interesting approach, compared to the copper filament printing, which uses a mix of copper particles and plastic instead....
We actually copperplated a billiard ball, but I have also seen results from this company on SLA printed plastics.
Yes, I have a delta arm machine - a SeeMeCNC RoStock MAX V2. Love this machine! Fast, accurate, and reliable. I haven't tried to push the resolution limits yet - been too busy printing things for customers!
I have never done delamination testing over temperature - and never needed to know so I've not looked it up. But I'm SURE there's good info out there...
I am printing in carbon fiber impregnated PLA (from ProtoPasta), plain PLA, and ABS. Haven't tried any of the metal impregnated plastics yet, but they're on my list - I wonder how they'd transfer heat?
All depends on what temperatures one has to expect when using a 700W+ microwave generator.
When I read that R.Shawyer has burned through his frustum coppersheet walls on a few occasions, i fear all those type of 3Dprint materials will not last long before collapsing or even start to burn...
I'm not keen on even trying it....as i'm pretty sure it will fail.
The only solution would to drastically lower the power input. Question is then, will we then ever see any results from those low energy inputs? (keeping the baby-frustum in mind)
I think overall internal temperature should not exceed 70-80°C to use a copper plated filament 3Dprinted frustum...I'll have a heat conductivity test on the copper filament. Was going to test it anyway... :)
So, this experiment by RFMWGUY either:
a) it is not in resonance
or
b) it nullifies the reported claims of Shawyer and Yang if the RFMWGUY EM Drive is resonating with a high Q
...
1) The RFMWGUY EM Drive test is not resonating (effectively meaning a Q below 1,000) in the RFMWGUY experiments
and/or
2) Whatever "EM Drive thrust force" taking place pointing towards the small base is so small, so tiny, that it is completely overwhelmed by the thermal lift of the magnetron. This force would have to be as small as measured by Tajmar.
*********************
Ever since Maxwell showed that electromagnetic fields can exert pressure, experimental verification of Maxwell's electromagnetic stress had to contend with what became known as "the gas effect,"
It was only when experiments were conducted in vacuum, at the turn of the 19th century into the 20th century, that electromagnetic stress was able to be properly measured.
Neither Shawyer or Yang ever reported a single test conducted in vacuum.
The only organizations that have conducted tests in vacuum (NASA and TU Dresden) have reported force/InputPower values that are several orders of magnitude smaller than the values reported by Shawyer or Yang.
The importance of the thermal natural convection in air shown by RFMWGUY in this experiment is consistent with the well known scientific history of electromagnetic pressure measurements.
All depends on what temperatures one has to expect when using a 700W+ microwave generator.
When I read that R.Shawyer has burned through his frustum coppersheet walls on a few occasions, i fear all those type of 3Dprint materials will not last long before collapsing or even start to burn...
I'm not keen on even trying it....as i'm pretty sure it will fail.
The only solution would to drastically lower the power input. Question is then, will we then ever see any results from those low energy inputs? (keeping the baby-frustum in mind)
I think overall internal temperature should not exceed 70-80°C to use a copper plated filament 3Dprinted frustum...I'll have a heat conductivity test on the copper filament. Was going to test it anyway... :)
A pure magnitude plot don't tell anything about the possible under- or over-coupling, both looks very equal. Much better is a plot of the complex plane (beside the mag plot ;) ).
So, this experiment by RFMWGUY either:
a) it is not in resonance
or
b) it nullifies the reported claims of Shawyer and Yang if the RFMWGUY EM Drive is resonating with a high Q
...
Has anyone experimentally verified that a perforated frustum can resonate with a high Q?
I would bet he is very close to resonance, but the quality is probably much lower than 1000. Fooling around with our cylinder revealed that changing the movable plate by ~50 thou could result in dramatic differences in quality as seen by these S11 plots. Apples and oranges, yes, but making a resonator with a bandwidth of 2.45 MHz seems very difficult without some sort of tuning mechanism.
I need a movie.Great work aero! Looks very nice :)
https://drive.google.com/folderview?id=0B1XizxEfB23tRHpqYTU0TDc3RHM&usp=sharing (https://drive.google.com/folderview?id=0B1XizxEfB23tRHpqYTU0TDc3RHM&usp=sharing)
This is the current status of the loop antenna and I need some help to explain what I'm not seeing. It looks nice but I don't see proper behaviour of current reversal. But then, I don't know for sure what that would be so that's what I need help with. Time scale - I'm not accustom to thinking at the speed of light and here I have 3 complete cycles of the drive
output every 0.05 cycle. Maybe I should just output at every computational time step.
If someone would be so kind as to post a movie for me I can much better explain my question.
I need a movie.
https://drive.google.com/folderview?id=0B1XizxEfB23tRHpqYTU0TDc3RHM&usp=sharing (https://drive.google.com/folderview?id=0B1XizxEfB23tRHpqYTU0TDc3RHM&usp=sharing)
This is the current status of the loop antenna and I need some help to explain what I'm not seeing. It looks nice but I don't see proper behaviour of current reversal. But then, I don't know for sure what that would be so that's what I need help with. Time scale - I'm not accustom to thinking at the speed of light and here I have 3 complete cycles of the drive
output every 0.05 cycle. Maybe I should just output at every computational time step.
If someone would be so kind as to post a movie for me I can much better explain my question.
Second that but qualify, nice work X-ray too.I need a movie.Great work aero! Looks very nice :)
https://drive.google.com/folderview?id=0B1XizxEfB23tRHpqYTU0TDc3RHM&usp=sharing (https://drive.google.com/folderview?id=0B1XizxEfB23tRHpqYTU0TDc3RHM&usp=sharing)
This is the current status of the loop antenna and I need some help to explain what I'm not seeing. It looks nice but I don't see proper behaviour of current reversal. But then, I don't know for sure what that would be so that's what I need help with. Time scale - I'm not accustom to thinking at the speed of light and here I have 3 complete cycles of the drive
output every 0.05 cycle. Maybe I should just output at every computational time step.
If someone would be so kind as to post a movie for me I can much better explain my question.
@aero
Questions about your loop:
1) Is the length of the loop equal to 1lambda (it looks like that)?
2) Shows the visible pattern the H field component in the z direction? The file names suggest that...
Everyone read this? From Eagle WorksYes, this paper was pre-announced by Paul March (who is one of the co-authors) pre-publication, who also shared it at publication time (as a NASA report), and discussed in previous threads with Paul March and others in the forum :)
http://www.scirp.org/Journal/PaperInformation.aspx?PaperID=59027
Dr. Rodal -The harmonic signature of the RF power signal fed by the magnetron into the frustum has not been considered so far. The level and phasing of the second harmonic of the frequency for which the transfert of energy in the cavity is maximal may be the other key factor which makes the thrust phenomena possible.
I think the appropriate attitude to adopt is empirical, not theoretical. The reason I think that is that we are dealing with an 'impossible' phenomenon, so any theory is necessarily inadequate. Simulations and earlier experiments can guide future work, given the alternative is pure trial and error, which is not attractive.
What I don't think is appropriate is to neglect to follow up apparent effects because our theory says they are impossible. The whole idea is impossible in theory, after all.
I've presented some ideas that strongly suggest an effect correlated with magnetron operation in rfmwguy's first test. I agree with you, it's probably an artefact. Turning the frustum upside down and repeating the experiment will provide data for or against the idea of it being an artefact. Not doing the experiment because we think we know better will just leave a loose end.
Lastly, I think this is one of only a couple of hints of some EMdrive effect in the data which has been presented so far. This seems to me to make it even more important to follow it up, though of course it's up to rfmwguy's what he does.
Regards,
R.
Got to give them credit they are definitely trying to chip away at the QV immutability.Everyone read this? From Eagle WorksYes, this paper was pre-announced by Paul March (who is one of the co-authors) pre-publication, who also shared it at publication time (as a NASA report), and discussed in previous threads with Paul March and others in the forum :)
http://www.scirp.org/Journal/PaperInformation.aspx?PaperID=59027
I see that it has now been published in:
Journal of Modern Physics, 2015, 6, 1308-1320
One of the main purposes is to discuss Dr. White's hypothesis that there are different sub-levels to the Quantum Vacuum, and hence formally address the objection from some people that if the QV is the zero-point energy (as originally postulated by Einstein) then one should not be able to extract any energy from it. The paper intends to address the issue of inmutability and undegredability of the QV. In Dr. White's hypothesis the QV needs to be mutable and degradable if his explanation for EM Drive thrust is to hold.
**************************************************
This is an open access peer-reviewed journal that has a
Google h5-index=13 h5-median =19
https://scholar.google.com/citations?view_op=top_venues&hl=en&vq=phy
(https://scholar.google.com/citations?hl=en&view_op=search_venues&vq=Journal+of+Modern+Physics)
Prof. Dr. James Woodward, it is my understanding, is of the opinion that the only way that any propulsion out of the EM Drive could be justified using his Machian theory is if the EM Drive contains a dielectric insert as used by NASA in their experiments.Dr. Rodal -The harmonic signature of the RF power signal fed by the magnetron into the frustum has not been considered so far. The level and phasing of the second harmonic of the frequency for which the transfert of energy in the cavity is maximal may be the other key factor which makes the thrust phenomena possible.
I think the appropriate attitude to adopt is empirical, not theoretical. The reason I think that is that we are dealing with an 'impossible' phenomenon, so any theory is necessarily inadequate. Simulations and earlier experiments can guide future work, given the alternative is pure trial and error, which is not attractive.
What I don't think is appropriate is to neglect to follow up apparent effects because our theory says they are impossible. The whole idea is impossible in theory, after all.
I've presented some ideas that strongly suggest an effect correlated with magnetron operation in rfmwguy's first test. I agree with you, it's probably an artefact. Turning the frustum upside down and repeating the experiment will provide data for or against the idea of it being an artefact. Not doing the experiment because we think we know better will just leave a loose end.
Lastly, I think this is one of only a couple of hints of some EMdrive effect in the data which has been presented so far. This seems to me to make it even more important to follow it up, though of course it's up to rfmwguy's what he does.
Regards,
R.
I have found the rationale for this hypothesis in the writings of James F. Woodward who at my knowledge is alone to have proposed consistent theory and experiments about Machian mass fluctuation and its use for thrust generation without local momentum conservation (what we are all looking for). Even if at first sight the RF cavity device we are working on has little to see with the Woodward device (electrical capacities with PZT crystals), it is fully possible that they use both the same basic mechanism found and tested by Woodward : Generation by the fundamental power signal of two kinds of Periodic Mass Fluctuation, one of which is at two times the fundamental frequency and then generation via the second harmonic of a net thrust by pushing on an object made more massive by this mass fluctuation and then pulling it back when it is in a mass-reduced state.
In Woodward mind, the presence of this second harmonic seems absolutely necessary for a Machian thrust to appear. More over the phase of this harmonic could very well control the direction of the thrust.
It is why I suggest to characterize the harmonics of the RF signal fed in the cavity (via a spectrum analyser connected to a port of a test coupler) and to try to calculate the electromagnetic field at the second harmonic frequency inside the cavity. The measurement/control of the dephasing of the second harmonic would require some serious thinking ... :)
This made me think about the good ol' times when we could get a good picture of what the EagleWorks team was doing. With all the privileges of first hand information that entails. I just wish someone at Dresden was so forthcoming as Paul March was. But now we have to live with whatever we can get.In order not to jeopardize any of the employees at NASA Eagleworks, unfortunately we really have to wait until they are given official permission by NASA officials for them to disclose any of their research.
Anyone knows what are they up to now?
I decided that we need to see more data. The previous movie was for a time slice every 10 computational cycles, every 10 time steps. I made a new run outputting the image at every time step. The image is of the z component of the magnetic field. The circumference of the loop is 3 wavelengths. That's just so the small images will show on my computer screen.
https://drive.google.com/folderview?id=0B1XizxEfB23tYjVwZzJzWk9wckE&usp=sharing (https://drive.google.com/folderview?id=0B1XizxEfB23tYjVwZzJzWk9wckE&usp=sharing)
The problem that I don't understand has to do with the cycling of the drive current. As it stands, the complete loop is regenerated at every time step so as the current in the loop reverses direction the complete loop current fades away as current passes through zero. But at the speed of the current and the very fine resolution of the simulation, is that what really happens? It takes 200 time steps for the curent to make a complete circut of the loop so how can the current at a point 100 time steps behind (half way around the loop) go to zero at the same time as the drive current?
Same thing at power on. The complete loop is excited at power on but shouldn't the points on the loop be excited in turn, one more point per time step (assuming the loop points are synchronized with speed of current)?
The Casimir force arises as a result of a geometric conducting boundary in the form of two plates being placed in close proximity to one another such that the geometry of the cavity can preclude the ability for certain wavelengths of light from being present in one direction
@aero
Questions about your loop:
1) Is the length of the loop equal to 1lambda (it looks like that)?
2) Shows the visible pattern the H field component in the z direction? The file names suggest that...
I decided that we need to see more data. The previous movie was for a time slice every 10 computational cycles, every 10 time steps. I made a new run outputting the image at every time step. The image is of the z component of the magnetic field. The circumference of the loop is 3 wavelengths. That's just so the small images will show on my computer screen.
https://drive.google.com/folderview?id=0B1XizxEfB23tYjVwZzJzWk9wckE&usp=sharing (https://drive.google.com/folderview?id=0B1XizxEfB23tYjVwZzJzWk9wckE&usp=sharing)
The problem that I don't understand has to do with the cycling of the drive current. As it stands, the complete loop is regenerated at every time step so as the current in the loop reverses direction the complete loop current fades away as current passes through zero. But at the speed of the current and the very fine resolution of the simulation, is that what really happens? It takes 200 time steps for the curent to make a complete circut of the loop so how can the current at a point 100 time steps behind (half way around the loop) go to zero at the same time as the drive current?
Same thing at power on. The complete loop is excited at power on but shouldn't the points on the loop be excited in turn, one more point per time step (assuming the loop points are synchronized with speed of current)?
@aero
Questions about your loop:
1) Is the length of the loop equal to 1lambda (it looks like that)?
2) Shows the visible pattern the H field component in the z direction? The file names suggest that...
I decided that we need to see more data. The previous movie was for a time slice every 10 computational cycles, every 10 time steps. I made a new run outputting the image at every time step. The image is of the z component of the magnetic field. The circumference of the loop is 3 wavelengths. That's just so the small images will show on my computer screen.
https://drive.google.com/folderview?id=0B1XizxEfB23tYjVwZzJzWk9wckE&usp=sharing (https://drive.google.com/folderview?id=0B1XizxEfB23tYjVwZzJzWk9wckE&usp=sharing)
The problem that I don't understand has to do with the cycling of the drive current. As it stands, the complete loop is regenerated at every time step so as the current in the loop reverses direction the complete loop current fades away as current passes through zero. But at the speed of the current and the very fine resolution of the simulation, is that what really happens? It takes 200 time steps for the curent to make a complete circut of the loop so how can the current at a point 100 time steps behind (half way around the loop) go to zero at the same time as the drive current?
Same thing at power on. The complete loop is excited at power on but shouldn't the points on the loop be excited in turn, one more point per time step (assuming the loop points are synchronized with speed of current)?
Excitation frequency, 2.50 GHz. Length of the loop? Circumference is 3 wavelengths. Yes, hz.pngs
Same kind of dipoles as always with phase shifting. A gap will be simple to add but do we really need it in the numerical model?
You are looking at, in this case, a set of 360 point sources phased around the loop. Of course they turn on at the same time. My question may have been reverse logic but I really wanted someone to decide, "That's Ok or no, that's not good enough for what we need.
If it's good enough I can take out the phasing, then I have a circle made up of point sources that flash on and off with perfect symmetry always shining the EM fields axially in the cavity. But in the real situation the antenna pattern will be more like a search light searching around the axis of rotation (horizontal loop), not like a fixed search light pointing straight up.
Excitation frequency, 2.50 GHz. Length of the loop? Circumference is 3 wavelengths. Yes, hz.pngs
Same kind of dipoles as always with phase shifting. A gap will be simple to add but do we really need it in the numerical model?
You are looking at, in this case, a set of 360 point sources phased around the loop. Of course they turn on at the same time. My question may have been reverse logic but I really wanted someone to decide, "That's Ok or no, that's not good enough for what we need.
If it's good enough I can take out the phasing, then I have a circle made up of point sources that flash on and off with perfect symmetry always shining the EM fields axially in the cavity. But in the real situation the antenna pattern will be more like a search light searching around the axis of rotation (horizontal loop), not like a fixed search light pointing straight up.
In the frustum you can throw out 1/4 or 1/2 wave making up the loop and make it 1/3 wavelength. You will get some interesting patterns.
Shell
Got to give them credit they are definitely trying to chip away at the QV immutability.Everyone read this? From Eagle WorksYes, this paper was pre-announced by Paul March (who is one of the co-authors) pre-publication, who also shared it at publication time (as a NASA report), and discussed in previous threads with Paul March and others in the forum :)
http://www.scirp.org/Journal/PaperInformation.aspx?PaperID=59027
I see that it has now been published in:
Journal of Modern Physics, 2015, 6, 1308-1320
One of the main purposes is to discuss Dr. White's hypothesis that there are different sub-levels to the Quantum Vacuum, and hence formally address the objection from some people that if the QV is the zero-point energy (as originally postulated by Einstein) then one should not be able to extract any energy from it. The paper intends to address the issue of inmutability and undegredability of the QV. In Dr. White's hypothesis the QV needs to be mutable and degradable if his explanation for EM Drive thrust is to hold.
**************************************************
This is an open access peer-reviewed journal that has a
Google h5-index=13 h5-median =19
https://scholar.google.com/citations?view_op=top_venues&hl=en&vq=phy
(https://scholar.google.com/citations?hl=en&view_op=search_venues&vq=Journal+of+Modern+Physics)
Thanks for the reply, I had not seen it.
Shell
Sorry to confuse you, I should have followed you more closely. I wanted you to do a 1/4 wave as it will be easier to see if you got it right with your simulation in meep.Excitation frequency, 2.50 GHz. Length of the loop? Circumference is 3 wavelengths. Yes, hz.pngs
Same kind of dipoles as always with phase shifting. A gap will be simple to add but do we really need it in the numerical model?
You are looking at, in this case, a set of 360 point sources phased around the loop. Of course they turn on at the same time. My question may have been reverse logic but I really wanted someone to decide, "That's Ok or no, that's not good enough for what we need.
If it's good enough I can take out the phasing, then I have a circle made up of point sources that flash on and off with perfect symmetry always shining the EM fields axially in the cavity. But in the real situation the antenna pattern will be more like a search light searching around the axis of rotation (horizontal loop), not like a fixed search light pointing straight up.
In the frustum you can throw out 1/4 or 1/2 wave making up the loop and make it 1/3 wavelength. You will get some interesting patterns.
Shell
Shell - A little more specific here, please. What? are you talking about. the frustum length is 0.1634 meters, the loop doesn't have a length, it has a radius, a diameter and a circumference. Circumference is a parameter now but of course I could change that. So again, What?
I'm not quite sure if I follow what he is trying to say and I think I see it but I want to read it again. I do know new evidence is showing that the QV isn't as non-mutable as it was once seemed and can be something lower than zero.Got to give them credit they are definitely trying to chip away at the QV immutability.Everyone read this? From Eagle WorksYes, this paper was pre-announced by Paul March (who is one of the co-authors) pre-publication, who also shared it at publication time (as a NASA report), and discussed in previous threads with Paul March and others in the forum :)
http://www.scirp.org/Journal/PaperInformation.aspx?PaperID=59027
I see that it has now been published in:
Journal of Modern Physics, 2015, 6, 1308-1320
One of the main purposes is to discuss Dr. White's hypothesis that there are different sub-levels to the Quantum Vacuum, and hence formally address the objection from some people that if the QV is the zero-point energy (as originally postulated by Einstein) then one should not be able to extract any energy from it. The paper intends to address the issue of inmutability and undegredability of the QV. In Dr. White's hypothesis the QV needs to be mutable and degradable if his explanation for EM Drive thrust is to hold.
**************************************************
This is an open access peer-reviewed journal that has a
Google h5-index=13 h5-median =19
https://scholar.google.com/citations?view_op=top_venues&hl=en&vq=phy
(https://scholar.google.com/citations?hl=en&view_op=search_venues&vq=Journal+of+Modern+Physics)
Thanks for the reply, I had not seen it.
Shell
Those comparisons toward the end between the pressure waves in a ringing basketball and the hydrogen electron orbitals are...quite interesting.
Prof. Dr. James Woodward, it is my understanding, is of the opinion that the only way that any propulsion out of the EM Drive could be justified using his Machian theory is if the EM Drive contains a dielectric insert as used by NASA in their experiments.
Therefore, the experiments performed by RFMWGUY, as well as the latest experiments and designs of Shaywer, and the experiments of Yang and Tajmar, for example cannot result in space propulsion according to Prof. Woodward's theory since all these experiments do not include any dielectric insert. Prof. Woodward, as I understand it, maintains that an EM Drive tested without a dielectric insert cannot obtain any thrust whatsoever for space propulsion because such thrust is precluded by what Prof. Woodward calls "THE LAW" in capital letters: the law of conservation of momentum. You are welcome to contact Prof. Woodward to find out whether my understanding is up to date (and if so, whether your understanding of his theory is being properly applied to an EM Drive without any dielectric insert).
"Should the relative phase of the mass fluctuation and the magnetic part of the Lorentz force be auspicious, a stationary force should result. But such a force, if present, is a result of the mass fluctuation that arises from the inertial coupling of the constituents of the dielectric to the rest of the universe. It is not due to a local violation of the conservation of momentum in a purely electrodynamical system. It is worth remarking that a stationary force in a system of this sort may be expected even if the “substance” between the plates of the capacitor is the vacuum. If the charged particle pair production in the vacuum of quantum lore actually takes place, the pairs should experience the same effects as material dielectric media. So exploration of this sort of arrangement of circuit elements has scientific value (as a test of the “polarizable vacuum” conjecture), as well as potential technological implications."
" For example, generation of the effect seems to depend quite critically on the production of higher harmonics in the PZT stacks, for sinking a lot of power into a stack at a mechanical resonance of the stack is not, itself, sufficient to yield an effect. "
I'm not quite sure if I follow what he is trying to say and I think I see it but I want to read it again. I do know new evidence is showing that the QV isn't as non-mutable as it was once seemed and can be something lower than zero.Got to give them credit they are definitely trying to chip away at the QV immutability.Everyone read this? From Eagle WorksYes, this paper was pre-announced by Paul March (who is one of the co-authors) pre-publication, who also shared it at publication time (as a NASA report), and discussed in previous threads with Paul March and others in the forum :)
http://www.scirp.org/Journal/PaperInformation.aspx?PaperID=59027
I see that it has now been published in:
Journal of Modern Physics, 2015, 6, 1308-1320
One of the main purposes is to discuss Dr. White's hypothesis that there are different sub-levels to the Quantum Vacuum, and hence formally address the objection from some people that if the QV is the zero-point energy (as originally postulated by Einstein) then one should not be able to extract any energy from it. The paper intends to address the issue of inmutability and undegredability of the QV. In Dr. White's hypothesis the QV needs to be mutable and degradable if his explanation for EM Drive thrust is to hold.
**************************************************
This is an open access peer-reviewed journal that has a
Google h5-index=13 h5-median =19
https://scholar.google.com/citations?view_op=top_venues&hl=en&vq=phy
(https://scholar.google.com/citations?hl=en&view_op=search_venues&vq=Journal+of+Modern+Physics)
Thanks for the reply, I had not seen it.
Shell
Those comparisons toward the end between the pressure waves in a ringing basketball and the hydrogen electron orbitals are...quite interesting.
(warning Clickbait) http://phys.org/news/2015-08-scientists-particle.html
I finally finished the loop antenna modeling exercise. Not sure if this is still useful but I will post here. Likely the patterns are the most useful part - as they should give some idea of what modes can be stimulated.Herman,
These models and results are made using a version of the NEC codes (specifically EZNEC). NEC antenna modeling is not perfect but if you stay within the constraints it can produce qualitatively useful results. As with all such models, quantitative results are highly dependent on many factors including geometry, signal quality, and many more. Hopefully these will be of use - particularly if the loops are in a spherical chicken in a vacuum.
I modeled three sizes of antenna 1/2, 1, and 2 wavelength circumference, at three different heights - 1/4, 1/2 and 1 wavelength. Also modeled each of these configurations for loops both parallel to and normal to their ground plane.
Sorry for how long this took - as some of you know I have been in the process of retiring and unfortunately this exercise mostly had to take place late in evening after all other boring but necessary stuff had been done. I am now free and hope to start detailed planning for my own DIY experiments soon.
Herman
Here's a 4NEC2 file of a small loop, I ran cases for .36 inch dia and am posting the NASA 0.55 inch loop. They serve as an approximate starting point in free space, in a cavity the impedance will be reduced by the mirroring of the walls. Impedance is 133-j60 and SWR 3.28. You will have to rename the NEC file, replace dot with a period and delete txt. The images are bmp files, replace dot with a period and remove txt.
You know what they say? Don't piss off the cat. ;)I'm not quite sure if I follow what he is trying to say and I think I see it but I want to read it again. I do know new evidence is showing that the QV isn't as non-mutable as it was once seemed and can be something lower than zero.Got to give them credit they are definitely trying to chip away at the QV immutability.Everyone read this? From Eagle WorksYes, this paper was pre-announced by Paul March (who is one of the co-authors) pre-publication, who also shared it at publication time (as a NASA report), and discussed in previous threads with Paul March and others in the forum :)
http://www.scirp.org/Journal/PaperInformation.aspx?PaperID=59027
I see that it has now been published in:
Journal of Modern Physics, 2015, 6, 1308-1320
One of the main purposes is to discuss Dr. White's hypothesis that there are different sub-levels to the Quantum Vacuum, and hence formally address the objection from some people that if the QV is the zero-point energy (as originally postulated by Einstein) then one should not be able to extract any energy from it. The paper intends to address the issue of inmutability and undegredability of the QV. In Dr. White's hypothesis the QV needs to be mutable and degradable if his explanation for EM Drive thrust is to hold.
**************************************************
This is an open access peer-reviewed journal that has a
Google h5-index=13 h5-median =19
https://scholar.google.com/citations?view_op=top_venues&hl=en&vq=phy
(https://scholar.google.com/citations?hl=en&view_op=search_venues&vq=Journal+of+Modern+Physics)
Thanks for the reply, I had not seen it.
Shell
Those comparisons toward the end between the pressure waves in a ringing basketball and the hydrogen electron orbitals are...quite interesting.
(warning Clickbait) http://phys.org/news/2015-08-scientists-particle.html
I think the point is that wave-like behavior of the quantum vacuum could potentially explain things in the quantum world just as well as blind adherence to Schroedinger's equation. And therefore could also give the EM-Drive something to "push against". It's basically the Copenhagen vs the deBroglie-Bohm interpretations.
Prof. Dr. James Woodward, it is my understanding, is of the opinion that the only way that any propulsion out of the EM Drive could be justified using his Machian theory is if the EM Drive contains a dielectric insert as used by NASA in their experiments.
Therefore, the experiments performed by RFMWGUY, as well as the latest experiments and designs of Shaywer, and the experiments of Yang and Tajmar, for example cannot result in space propulsion according to Prof. Woodward's theory since all these experiments do not include any dielectric insert. Prof. Woodward, as I understand it, maintains that an EM Drive tested without a dielectric insert cannot obtain any thrust whatsoever for space propulsion because such thrust is precluded by what Prof. Woodward calls "THE LAW" in capital letters: the law of conservation of momentum. You are welcome to contact Prof. Woodward to find out whether my understanding is up to date (and if so, whether your understanding of his theory is being properly applied to an EM Drive without any dielectric insert).
The principle explored by Dr Woodward to induce Machian mass fluctuation must be distinguished from his particular engineering implementation which uses dielectric capacity to put the highest possible energy on accelerated matter. Woodward could well have used magnetic energy put in high permeability material. Moreover Woodward does not exclude the use of polarizable vacuum to play with this Machian mass fluctuation as he explains it in the following excerpt of his article "RAPID SPACETIME TRANSPORT AND MACHIAN MASS FLUCTUATIONS: THEORY AND EXPERIMENT "
Quote"Should the relative phase of the mass fluctuation and the magnetic part of the Lorentz force be auspicious, a stationary force should result. But such a force, if present, is a result of the mass fluctuation that arises from the inertial coupling of the constituents of the dielectric to the rest of the universe. It is not due to a local violation of the conservation of momentum in a purely electrodynamical system. It is worth remarking that a stationary force in a system of this sort may be expected even if the “substance” between the plates of the capacitor is the vacuum. If the charged particle pair production in the vacuum of quantum lore actually takes place, the pairs should experience the same effects as material dielectric media. So exploration of this sort of arrangement of circuit elements has scientific value (as a test of the “polarizable vacuum” conjecture), as well as potential technological implications."
The importance of harmonics generation is outlined in this other excerpt of the same article :Quote" For example, generation of the effect seems to depend quite critically on the production of higher harmonics in the PZT stacks, for sinking a lot of power into a stack at a mechanical resonance of the stack is not, itself, sufficient to yield an effect. "
I give in the attachment the article of Woodward I refer to.
hello everybody!The experiment is performed in a garage and not in a vacuum. As discussed numerous times in this thread and lately regarding RFMWGUY's experiments, magnetrons get hot and therefore produce lifting thermal currents due to natural convection. Any such test should either be conducted in a vacuum or otherwise the thermal lifting forces should be properly accounted for and not ignored when claiming "lifting effects".
do you know this work of Chris Hardeman in 2001 with microwaves
http://jnaudin.free.fr/html/gravshld.htm
best regards
hello everybody!Don't know about antigravity but sure admire the shop mechanics and workmanship. The wave generator appears to be a modified waveguide log spiral cavity that transitions the TE10 to a three way TE11 circular splitter that feeds three paralleled spherical resonators. A modeler's nightmare in any EM sim. Amazing what can be done with fiberglass,sheet metal and aluminum foil, wonder how much more copper would have cost.
do you know this work of Chris Hardeman in 2001 with microwaves
http://jnaudin.free.fr/html/gravshld.htm
best regards
Aero -
The Q value for rfmwguy's mesh frustrum seems to be of interest at the moment.
It was a while back, but if I recall correctly, you said that creating a MEEP control file for a mesh frustrum would be way too much effort.
It occurred to me yesterday that I may be able to compute and output a complex file using Excel if I knew the syntax required and it was reasonably tractable (and I could compute the position data for the holes!). Doubtless there are other ways, but this is one I'm familiar with.
I know the Q values from MEEP are somewhat controversial, but with the correct control files we might see how MEEP thinks Q would change when holes are added.
Anyway, I'm volunteering to help if this is something you want to have a look at.
R.
hello everybody!Don't know about antigravity but sure admire the shop mechanics and workmanship. The wave generator appears to be a modified waveguide log spiral cavity that transitions the TE10 to a three way TE11 circular splitter that feeds three paralleled spherical resonators. A modeler's nightmare in any EM sim. Amazing what can be done with fiberglass,sheet metal and aluminum foil, wonder how much more copper would have cost.
do you know this work of Chris Hardeman in 2001 with microwaves
http://jnaudin.free.fr/html/gravshld.htm
best regards
Buoyancy and thermal interference's can be ruled out as the cause of the effects as the device never gets hot.
Would someone please make a movie of this loop antenna?
https://drive.google.com/folderview?id=0B1XizxEfB23tdlZwUGI3NGc4eXc&usp=sharing (https://drive.google.com/folderview?id=0B1XizxEfB23tdlZwUGI3NGc4eXc&usp=sharing)
...
Would someone please make a movie of this loop antenna?Whatever you have changed this looks much more natural than the last try.
https://drive.google.com/folderview?id=0B1XizxEfB23tdlZwUGI3NGc4eXc&usp=sharing (https://drive.google.com/folderview?id=0B1XizxEfB23tdlZwUGI3NGc4eXc&usp=sharing)
The drive frequency is 2.47 GHz, loop circumference is 1 wave length and the run is for 3 cycles with 20 png's output per cycle.
It looks good to me. That doesn't mean that it will do what we expect but it is a start.
Now, if SeeShells will only tell me, in English, what it is that she is measuring with 1/4, 1/2 and 1/3 wavelength then I would make some test runs. :)
But I think I will go this way.
All DYI'ers. Acceptable loop antenna specification is "circumference of the loop" in wave lengths of the drive center frequency. The drive center frequency must also be specified. The x, y and z coordinate location of the center of the loop must also be specified in wavelengths and referenced to either the 0, 0, 0 point at the mid-point of the axis of rotation of the cavity, or to one or the other of the inside face of the big or small end and the side wall.
This requirement for sound specification also holds for dipole and stub antennas, just substitute length for circumference and dipole or stub for loop and add axial or lateral orientation.
Again, all dimensions must be specified in wave lengths, or a fraction of, or a rational fraction of wavelengths.
The loop can be tipped off horizontal up to 90 degrees rotation about the y axis. Tipping the loop about the x axis is not implemented.
@aeroWould someone please make a movie of this loop antenna?Whatever you have changed this looks much more natural than the last try.
https://drive.google.com/folderview?id=0B1XizxEfB23tdlZwUGI3NGc4eXc&usp=sharing (https://drive.google.com/folderview?id=0B1XizxEfB23tdlZwUGI3NGc4eXc&usp=sharing)
The drive frequency is 2.47 GHz, loop circumference is 1 wave length and the run is for 3 cycles with 20 png's output per cycle.
It looks good to me. That doesn't mean that it will do what we expect but it is a start.
Now, if SeeShells will only tell me, in English, what it is that she is measuring with 1/4, 1/2 and 1/3 wavelength then I would make some test runs. :)
But I think I will go this way.
All DYI'ers. Acceptable loop antenna specification is "circumference of the loop" in wave lengths of the drive center frequency. The drive center frequency must also be specified. The x, y and z coordinate location of the center of the loop must also be specified in wavelengths and referenced to either the 0, 0, 0 point at the mid-point of the axis of rotation of the cavity, or to one or the other of the inside face of the big or small end and the side wall.
This requirement for sound specification also holds for dipole and stub antennas, just substitute length for circumference and dipole or stub for loop and add axial or lateral orientation.
Again, all dimensions must be specified in wave lengths, or a fraction of, or a rational fraction of wavelengths.
The loop can be tipped off horizontal up to 90 degrees rotation about the y axis. Tipping the loop about the x axis is not implemented.
@aeroWhatever you have changed this looks much more natural than the last try.
... snip ...
Can you try either a run with the same frequency but 2 times the actual circumference, or two times the frequency of the last run?
The background is that in such a test there has to be two more nodes along the circumference. That would be a simple way to test your code.
Prof. Dr. James Woodward, it is my understanding, is of the opinion that the only way that any propulsion out of the EM Drive could be justified using his Machian theory is if the EM Drive contains a dielectric insert as used by NASA in their experiments.
Therefore, the experiments performed by RFMWGUY, as well as the latest experiments and designs of Shaywer, and the experiments of Yang and Tajmar, for example cannot result in space propulsion according to Prof. Woodward's theory since all these experiments do not include any dielectric insert. Prof. Woodward, as I understand it, maintains that an EM Drive tested without a dielectric insert cannot obtain any thrust whatsoever for space propulsion because such thrust is precluded by what Prof. Woodward calls "THE LAW" in capital letters: the law of conservation of momentum. You are welcome to contact Prof. Woodward to find out whether my understanding is up to date (and if so, whether your understanding of his theory is being properly applied to an EM Drive without any dielectric insert).
The principle explored by Dr Woodward to induce Machian mass fluctuation must be distinguished from his particular engineering implementation which uses dielectric capacity to put the highest possible energy on accelerated matter. Woodward could well have used magnetic energy put in high permeability material. Moreover Woodward does not exclude the use of polarizable vacuum to play with this Machian mass fluctuation as he explains it in the following excerpt of his article "RAPID SPACETIME TRANSPORT AND MACHIAN MASS FLUCTUATIONS: THEORY AND EXPERIMENT "
Quote"Should the relative phase of the mass fluctuation and the magnetic part of the Lorentz force be auspicious, a stationary force should result. But such a force, if present, is a result of the mass fluctuation that arises from the inertial coupling of the constituents of the dielectric to the rest of the universe. It is not due to a local violation of the conservation of momentum in a purely electrodynamical system. It is worth remarking that a stationary force in a system of this sort may be expected even if the “substance” between the plates of the capacitor is the vacuum. If the charged particle pair production in the vacuum of quantum lore actually takes place, the pairs should experience the same effects as material dielectric media. So exploration of this sort of arrangement of circuit elements has scientific value (as a test of the “polarizable vacuum” conjecture), as well as potential technological implications."
The importance of harmonics generation is outlined in this other excerpt of the same article :Quote" For example, generation of the effect seems to depend quite critically on the production of higher harmonics in the PZT stacks, for sinking a lot of power into a stack at a mechanical resonance of the stack is not, itself, sufficient to yield an effect. "
I give in the attachment the article of Woodward I refer to.
Go on this way, it looks right :)@aeroWhatever you have changed this looks much more natural than the last try.
... snip ...
Can you try either a run with the same frequency but 2 times the actual circumference, or two times the frequency of the last run?
The background is that in such a test there has to be two more nodes along the circumference. That would be a simple way to test your code.
Yes, I made that run - see attached. I did run it with circumference of 3 wave lengths also but I neglected to save that data set. It looked right though with 6 nodes along the circumference.
These are point sources distributed around in a loop and turned on in sequence synchronized with meep-time. Sequencing the turn-on, as lmbfan pointed out, maintains the phasing around the loop. Thanks lmbfan. So I don't need to fool with manually phasing the source with amplitude. It is much less complex.
It seems that meep will not do a dipole source at arbitrary angles to the primary axis so I'm forced to use point sources. There are no sequenced dipoles, and seemingly no support in meep for that except parallel to primary axis.
The smaller antenna
No. Circumference Lambda/4 (or Lambda/3 like Shell said).QuoteThe smaller antenna
Are you referring to the antenna with circumference of 1 wavelength?
An artefact of my implementation is that as the loop gets smaller the number of point sources making up the loop are reduced. It is still one point for every meep time step but it takes a lot fewer time steps to walk around the smaller loop. I don't know if that will have an adverse effect or not. It does affect the amplitude of the signal.Yes smaller loops gives lower amplitudes(also true in the real world, lower coupling...), but the wrong pattern at the loop could lead to a wrong field pattern means wrong mode..
In for a minute then have to dash off. A friend needs a lift her car broke down.An artefact of my implementation is that as the loop gets smaller the number of point sources making up the loop are reduced. It is still one point for every meep time step but it takes a lot fewer time steps to walk around the smaller loop. I don't know if that will have an adverse effect or not. It does affect the amplitude of the signal.Yes smaller loops gives lower amplitudes(also true in the real world, lower coupling...), but the wrong pattern at the loop could lead to a wrong field pattern means wrong mode..
On the other hand (for most geometries of such a resonator) there is only one mode possible, theoretically.
I don't believe that this is an artefact, half the number of points means you will see only one color for each half cycle. (Is that right??)
How it looks like for a lambda/4 circumference of the loop? Can you upload one or two full cycles? Myself or someone else will make a gif based on it :)
I've been making resonance runs for this antenna with the circumferences mentioned and see two interesting differences in the numbers from the dipole antennas used previously.
First though, the resonant frequency seems to be the same 2.50 GHz calculated before. More exactly, this
2.50021516E+009,
2.49990486E+009,
2.49989601E+009
for three runs.
1 ) The calculated quality factor is much lower whether excited by a magnetic or an electric source. Now, I am using all three components to excite the cavity (Ex, Ey, Ex) or (Hx, Hy, Hz) and maybe this is wrong. Does anyone know?
2 ) And this is interesting. When the drive frequency is less than the resonance frequency, Q does not suffer very much (20%) but the imaginary part of the complex amplitude is huge compared to the real part. This characteristic goes away when driving the cavity at the Harminv calculated resonant frequency. I don't recall what this means but I think I recall that the large imaginary component was related to something important. Dispersion, maybe?
Anyway, I can organize and post those numbers if there is interest.
...What component(s) were you using for the straight dipole antenna you used to excite TM modes in the initial runs?
1 ) The calculated quality factor is much lower whether excited by a magnetic or an electric source. Now, I am using all three components to excite the cavity (Ex, Ey, Ex) or (Hx, Hy, Hz) and maybe this is wrong. Does anyone know?...
...What component(s) were you using for the straight dipole antenna you used to excite TM modes in the initial runs?
1 ) The calculated quality factor is much lower whether excited by a magnetic or an electric source. Now, I am using all three components to excite the cavity (Ex, Ey, Ex) or (Hx, Hy, Hz) and maybe this is wrong. Does anyone know?...
...What component(s) were you using for the straight dipole antenna you used to excite TM modes in the initial runs?
1 ) The calculated quality factor is much lower whether excited by a magnetic or an electric source. Now, I am using all three components to excite the cavity (Ex, Ey, Ex) or (Hx, Hy, Hz) and maybe this is wrong. Does anyone know?...
I used each of them but only one at a time. A single component exciting the cavity for each of 6 runs. All 6 Q values were higher than the Q I'm getting with the loop. One by only a small factor (1.5) and the rest by orders of magnitude. It may be that I am not detecting the right mode, using Hx and keep forgetting to change it. Hx is a TM mode component. But without your question, that possibility wouldn't have occurred to me for days. I'll check now.
Regarding the huge Imaginary component, I'm talking about amplitude, not frequency. I agree, for frequency that couldn't happen.
...What component(s) were you using for the straight dipole antenna you used to excite TM modes in the initial runs?
1 ) The calculated quality factor is much lower whether excited by a magnetic or an electric source. Now, I am using all three components to excite the cavity (Ex, Ey, Ex) or (Hx, Hy, Hz) and maybe this is wrong. Does anyone know?...
I used each of them but only one at a time. A single component exciting the cavity for each of 6 runs. All 6 Q values were higher than the Q I'm getting with the loop. One by only a small factor (1.5) and the rest by orders of magnitude. It may be that I am not detecting the right mode, using Hx and keep forgetting to change it. Hx is a TM mode component. But without your question, that possibility wouldn't have occurred to me for days. I'll check now.
Regarding the huge Imaginary component, I'm talking about amplitude, not frequency. I agree, for frequency that couldn't happen.
So, if you used only one component before, why use 3 components now?
I can see using 2 components for a circle instead of 1 component for a straight dipole aligned along one of the Cartesian axes. To define a component at an angle to the Cartesian axes you need the 2 components in the plane of the circle, but I have no idea as to why you are using a 3rd component, which is perpendicular to that plane.
Try to use a H(z) component detector (if possible) at or close too the central axis, lambda/4 distance to the smaller end of the frustum. The magnetic field of TE012 would be strongest there....What component(s) were you using for the straight dipole antenna you used to excite TM modes in the initial runs?
1 ) The calculated quality factor is much lower whether excited by a magnetic or an electric source. Now, I am using all three components to excite the cavity (Ex, Ey, Ex) or (Hx, Hy, Hz) and maybe this is wrong. Does anyone know?...
I used each of them but only one at a time. A single component exciting the cavity for each of 6 runs. All 6 Q values were higher than the Q I'm getting with the loop. One by only a small factor (1.5) and the rest by orders of magnitude. It may be that I am not detecting the right mode, using Hx and keep forgetting to change it. Hx is a TM mode component. But without your question, that possibility wouldn't have occurred to me for days. I'll check now.
Regarding the huge Imaginary component, I'm talking about amplitude, not frequency. I agree, for frequency that couldn't happen.
So, if you used only one component before, why use 3 components now?
I can see using 2 components for a circle instead of 1 component for a straight dipole aligned along one of the Cartesian axes. To define a component at an angle to the Cartesian axes you need the 2 components in the plane of the circle, but I have no idea as to why you are using a 3rd component, which is perpendicular to that plane.
Well, no better idea, and anyway that was left over from debugging. Both TE and TM have 3 components, that's why the capability is built in. I have done as you suggested and am now making a run with only Ex and Ey excitation. Those two components are in the TE mode which is what I am hoping to excite.
I did change the Harminv detection location and component to Ey located 1/4 wavelength from the small end and maybe 70% toward the wall from the zero axis. It has been very near the center of the cavity. (Where is the best place to locate the detector?) This change increased the calculated Q to 7800 which is up from 3722. That is of course another indication of the futility of trying to adjust the copper model to get realistic calculated Q values. The calculated Q depends on several seemingly extraneous parameters not related to the material model.
Ok - run finished - exciting with only Ex and Ey reduced Q to 6661 and reduced the detected resonant frequency by 10 kHz. And in case I didn't mention it, this is with a 1/4 wave length circumference loop, 1/4 wavelength from the big end and centered.
The text by Woodward you refer to was cowritten with Paul March:Sorry for the missing of the other authors of the article but as you have seen in the version retrieved on the WEB and that I have attached in my previous post, Woodward was the only cited author.
Woodward, James F.; Mahood, Thomas L.; March, Paul (July 2001). "Rapid Spacetime Transport and Machian Mass Fluctuations: Theory and Experiment" (http://physics.fullerton.edu/~jimw/Jpcawf1.pdf). JPC 2001 Proceedings. 37th AIAA/ASME Joint Propulsion Conference, Salt Lake City, Utah. American Institute of Aeronautics and Astronautics. doi:10.2514/6.2001-3907
Most importantly, it was written in 2001, while Puthof's Polarizable Vacuum theory was only a few months old. Nowadays Woodward does not think PV is realistic anymore, nor any ZPF theory (including McCulloch's MiHsC or White's QVF conjecture) to explain Mach effects. He is very clear about that when asked on that matter.
Woodward is even currently writing a paper demonstrating why virtual particles of the vacuum can not be used for propulsion.
Question: "What do you think of the EMdrive work?"
March's answer: The proposed E&M/SRT conjecture IMO is garbage. The experimental results is tantalizing, but it has to be repeated in a vacuum chamber to get rid of possible spurious error sources for the thrust signatures observed. If it still moves in a 1x10-4 Torr vacuum, then we have to explain what is going on in view of Jim's work.
...What component(s) were you using for the straight dipole antenna you used to excite TM modes in the initial runs?
1 ) The calculated quality factor is much lower whether excited by a magnetic or an electric source. Now, I am using all three components to excite the cavity (Ex, Ey, Ex) or (Hx, Hy, Hz) and maybe this is wrong. Does anyone know?...
I used each of them but only one at a time. A single component exciting the cavity for each of 6 runs. All 6 Q values were higher than the Q I'm getting with the loop. One by only a small factor (1.5) and the rest by orders of magnitude. It may be that I am not detecting the right mode, using Hx and keep forgetting to change it. Hx is a TM mode component. But without your question, that possibility wouldn't have occurred to me for days. I'll check now.
Regarding the huge Imaginary component, I'm talking about amplitude, not frequency. I agree, for frequency that couldn't happen.
So, if you used only one component before, why use 3 components now?
I can see using 2 components for a circle instead of 1 component for a straight dipole aligned along one of the Cartesian axes. To define a component at an angle to the Cartesian axes you need the 2 components in the plane of the circle, but I have no idea as to why you are using a 3rd component, which is perpendicular to that plane.
Well, no better idea, and anyway that was left over from debugging. Both TE and TM have 3 components, that's why the capability is built in. I have done as you suggested and am now making a run with only Ex and Ey excitation. Those two components are in the TE mode which is what I am hoping to excite.
I did change the Harminv detection location and component to Ey located 1/4 wavelength from the small end and maybe 70% toward the wall from the zero axis. It has been very near the center of the cavity. (Where is the best place to locate the detector?) This change increased the calculated Q to 7800 which is up from 3722. That is of course another indication of the futility of trying to adjust the copper model to get realistic calculated Q values. The calculated Q depends on several seemingly extraneous parameters not related to the material model.
Ok - run finished - exciting with only Ex and Ey reduced Q to 6661 and reduced the detected resonant frequency by 10 kHz. And in case I didn't mention it, this is with a 1/4 wave length circumference loop, 1/4 wavelength from the big end and centered.
New meep simulations source link, below.
I've shared my folder meeper-files, which is laid out as follows:
meeper-files/
CE2-0009-150904/ - all files associated with this run in this folder
cvs-directory/ - the cvs files from the Continuous run
400+ files
CE2-8Ey-dual_dipoles-250-csv.log - log file from running CE2-csv.sh
CE2-dual_dipoles-250res.ctl - control file for the Continuous run at 250 resolution
CE2-dual_dipoles-C-250res.log - log file from Continuous run
CE2-dual_dipoles-G.ctl - control file for the Gaussian run at 100 resolution
CE2-dual_dipoles-G.log - log file from Gaussian run
meep-data-description-CE-2r9-32cy.txt - my take at the data description file
scripts/
CE2-csv.sh - my current version of the parameterized script file
Note that in the future, there will be better agreement between run names (CE2r9), directory names (CE2-0009-150904), control file names (CE2-dual_dipoles-xxx), and log file names. Sorry about that - it's been an evolution. I can recreate the files with the CE2-0009 common prefix, if you'd like.
Link to meeper-files folder is https://drive.google.com/folderview?id=0B527OOY4hxdZfldTN2FoVm5SRDZ2MHFJYmhaM2ZFcXVEeklpd3NnTy1RUUtnS3d1YllCWGc&usp=sharing
Folder is shared public for viewing only.
Hope you'll find them useful.
Edit - correct root folder name to meeper-files.
Trying to put more time into the build as I'm getting in the final hardware. Should have the waveguide to coax in today and splitters. Different laptop arriving today also that needs to be setup, the old one never did work and had to fight to get a refund, thank goodness I've been an ebayier for 14 years and have a good record.
Worked on the lasers yesterday getting the pinhole lens to work and tested the Faraday cage with the access ports for the beam, did very well. Laid out the ceramics for drilling for the center quartz rod today. Figured out the mounting for the first surface mirrors and got the hardware around to place them. Plus a bazzilion other things in verifying and profiling the test rig.
A good friend sent me a picture of a eco friendly wood power frustum, aero would you like to run this in your meep?
Will have drawings for you in a bit aero, less confusion with them I think.
Shell
The smaller end of the frustum tends to correlate very well to the mode TE012 sizing in position to the magnetic fields. I scaled a simulation of the magnetic fields and dropped them into a 3D model of the CE frustum and this is what looks like. The placement into the smaller end goes against the wisdom of 1/4 wavelengths in a dipole TExx mode to place it into the larger end but we are exciting a TE mode exciting the magnetic fields with the loop more like a coil winding.The Lambda/4 loop seems too tiny while looking at the field configuration. Your 3 Lambda design may work, we will see :)
If aero want to excite this configuration it would mirror what X_Ray was thinking in coupling to the modes. butttttt...
I think we are going to have to go to a dual loop placement into the mode shapes using a smaller loop in the smaller end of the cavity with phasing shifted to match the mode magnetic field direction to get a real stable TE012 and I'm working on the drawing and calculations to do just that.
Shell
It is a tiny lambda/4 loop but your right the 1/3 seems to be a better working model.The smaller end of the frustum tends to correlate very well to the mode TE012 sizing in position to the magnetic fields. I scaled a simulation of the magnetic fields and dropped them into a 3D model of the CE frustum and this is what looks like. The placement into the smaller end goes against the wisdom of 1/4 wavelengths in a dipole TExx mode to place it into the larger end but we are exciting a TE mode exciting the magnetic fields with the loop more like a coil winding.The Lambda/4 loop seems too tiny while looking at the field configuration. Your 3 Lambda design may work, we will see :)
If aero want to excite this configuration it would mirror what X_Ray was thinking in coupling to the modes. butttttt...
I think we are going to have to go to a dual loop placement into the mode shapes using a smaller loop in the smaller end of the cavity with phasing shifted to match the mode magnetic field direction to get a real stable TE012 and I'm working on the drawing and calculations to do just that.
Shell
Shell, why do you chose to use the free-space wavelength λ0, a value we meet only outside of the frustum, to calculate your loop antenna diameter?Are you sure that this is also true for the wave propagating/ traveling along the wire?
At 2.47 GHz and with the dimensions of your frustum we should have:
λ0 = 12.1 cm
λb = 14 cm
λs = 31 cm
Since the wavelength varies inside the frustum and is always superior to its value in free-space, shouldn't we calculate the local value of the wavelength according to the diameter of the frustum where you want to put the loop antenna, before deciding of the diameter of the loop antenna? Because of the variation of the wavelength, the loop antenna can't have a fixed diameter. Its diameter depends on its position along the axis in the frustum (I think).
Looks interesting if you are focussing on other mode shapes. For TE01p i don't think it will work (too asymmetric around the middle axis, wrong H field of the loops at this position comparing with the mode shape- it is the E "antinode").It is a tiny lambda/4 loop but your right the 1/3 seems to be a better working model.The smaller end of the frustum tends to correlate very well to the mode TE012 sizing in position to the magnetic fields. I scaled a simulation of the magnetic fields and dropped them into a 3D model of the CE frustum and this is what looks like. The placement into the smaller end goes against the wisdom of 1/4 wavelengths in a dipole TExx mode to place it into the larger end but we are exciting a TE mode exciting the magnetic fields with the loop more like a coil winding.The Lambda/4 loop seems too tiny while looking at the field configuration. Your 3 Lambda design may work, we will see :)
If aero want to excite this configuration it would mirror what X_Ray was thinking in coupling to the modes. butttttt...
I think we are going to have to go to a dual loop placement into the mode shapes using a smaller loop in the smaller end of the cavity with phasing shifted to match the mode magnetic field direction to get a real stable TE012 and I'm working on the drawing and calculations to do just that.
Shell
Just starting to lay out, not perfect cad work but I'll clean up later. This is my idea where I think we might want to end up at. Whatcha think?
Shell, why do you chose to use the free-space wavelength λ0, a value we meet only outside of the frustum, to calculate your loop antenna diameter?2.5GHz was the base frequency used.
At 2.47 GHz and with the dimensions of your frustum we should have:
λ0 = 12.1 cm
λb = 14 cm
λs = 31 cm
Since the wavelength varies inside the frustum and is always superior to its value in free-space, shouldn't we calculate the local value of the wavelength according to the diameter of the frustum where you want to put the loop antenna, before deciding of the diameter of the loop antenna? Because of the variation of the wavelength, the loop antenna can't have a fixed diameter. Its diameter depends on its position along the axis in the frustum (I think).
What would you suggest in keeping the dual loops to better excite a single mode? I can vary the phases of the loops if needed.Looks interesting if you are focussing on other mode shapes. For TE01p i don't think it will work (too asymmetric around the middle axis, wrong H field of the loops at this position comparing with the mode shape- it is the E "antinode").It is a tiny lambda/4 loop but your right the 1/3 seems to be a better working model.The smaller end of the frustum tends to correlate very well to the mode TE012 sizing in position to the magnetic fields. I scaled a simulation of the magnetic fields and dropped them into a 3D model of the CE frustum and this is what looks like. The placement into the smaller end goes against the wisdom of 1/4 wavelengths in a dipole TExx mode to place it into the larger end but we are exciting a TE mode exciting the magnetic fields with the loop more like a coil winding.The Lambda/4 loop seems too tiny while looking at the field configuration. Your 3 Lambda design may work, we will see :)
If aero want to excite this configuration it would mirror what X_Ray was thinking in coupling to the modes. butttttt...
I think we are going to have to go to a dual loop placement into the mode shapes using a smaller loop in the smaller end of the cavity with phasing shifted to match the mode magnetic field direction to get a real stable TE012 and I'm working on the drawing and calculations to do just that.
Shell
Just starting to lay out, not perfect cad work but I'll clean up later. This is my idea where I think we might want to end up at. Whatcha think?
The mode is given/predicted by the dimensions of the cavity and the frequency you are using. The only question is how good you are able to excite it. Thats aka coupling factor. The possibility of phase shift in your equipment together with the VNA could be very helpful i think.What would you suggest in keeping the dual loops to better excite a single mode? I can vary the phases of the loops if needed.Looks interesting if you are focussing on other mode shapes. For TE01p i don't think it will work (too asymmetric around the middle axis, wrong H field of the loops at this position comparing with the mode shape- it is the E "antinode").It is a tiny lambda/4 loop but your right the 1/3 seems to be a better working model.The smaller end of the frustum tends to correlate very well to the mode TE012 sizing in position to the magnetic fields. I scaled a simulation of the magnetic fields and dropped them into a 3D model of the CE frustum and this is what looks like. The placement into the smaller end goes against the wisdom of 1/4 wavelengths in a dipole TExx mode to place it into the larger end but we are exciting a TE mode exciting the magnetic fields with the loop more like a coil winding.The Lambda/4 loop seems too tiny while looking at the field configuration. Your 3 Lambda design may work, we will see :)
If aero want to excite this configuration it would mirror what X_Ray was thinking in coupling to the modes. butttttt...
I think we are going to have to go to a dual loop placement into the mode shapes using a smaller loop in the smaller end of the cavity with phasing shifted to match the mode magnetic field direction to get a real stable TE012 and I'm working on the drawing and calculations to do just that.
Shell
Just starting to lay out, not perfect cad work but I'll clean up later. This is my idea where I think we might want to end up at. Whatcha think?
I'm not sure either of the variable loop sizes as we are trying to excite a TExx mode although EWs was ~λ 14 cm. .55" @2.45GHz.
...
Now I agree with you that the Puthof's Polarizable Vacuum theory cannot be a replacement for General Relativity and its endorsement of Mach (not March ! ;)) intuition on the origin of inertia. It was also; I would say; the view of Puthof himself who clearly wrote in 1999 that the Polarizable Vacuum theory was not yet in a positon to explain both gravitational radiation and frame-dragging effects (base of Mach ideas on inertia incorporation in General Relativity).
Ok - run finished - exciting with only Ex and Ey reduced Q to 6661 and reduced the detected resonant frequency by 10 kHz. And in case I didn't mention it, this is with a 1/4 wave length circumference loop, 1/4 wavelength from the big end and centered.
@SeeShellsMy translation of what you wrote is the following:QuoteI'm not sure either of the variable loop sizes as we are trying to excite a TExx mode although EWs was ~λ 14 cm. .55" @2.45GHz.
Someone correct me if I'm wrong, but I seem to recall that EW was working at 1.93 GHz, not 2.45.
@X-Ray - Thanks, I have moved the detector to (.02, .02, (1/4 wl from SE)) that's x,y,z.
@Dr. Rodal -
Freq.= 2.5 GHZ, c= 299792458 m/s
Wl = 0.1199169832 ~= 0.12 meters
Quarter wavelength = 0.03 meters
Frustum meters wave lengths
length 0.1634 1.3616666667
BD 0.295 2.4583333333
SD 0.16 1.3333333333
Taper = 0.8261933905 0.8261933905
Dia @ ¼ wl = 0.2702141983 2.4335475316
Dia of 1/4 wave lengh loop=
Circumference/pi = 0.0095492966 0.0795774715
spelling
Dr. Rodel how can I compare your images and these of EW and draw any conclusions as to what is happening within the cavity? It's a little confusing.@SeeShellsMy translation of what you wrote is the following:QuoteI'm not sure either of the variable loop sizes as we are trying to excite a TExx mode although EWs was ~λ 14 cm. .55" @2.45GHz.
Someone correct me if I'm wrong, but I seem to recall that EW was working at 1.93 GHz, not 2.45.
@X-Ray - Thanks, I have moved the detector to (.02, .02, (1/4 wl from SE)) that's x,y,z.
@Dr. Rodal -
Freq.= 2.5 GHZ, c= 299792458 m/s
Wl = 0.1199169832 ~= 0.12 meters
Quarter wavelength = 0.03 meters
Frustum meters wave lengths
length 0.1634 1.3616666667
BD 0.295 2.4583333333
SD 0.16 1.3333333333
Taper = 0.8261933905 0.8261933905
Dia @ ¼ wl = 0.2702141983 2.4335475316
Dia of 1/4 wave lengh loop=
Circumference/pi = 0.0095492966 0.0795774715
spelling
Diameter of your loop = 0.0095493 meters
Diameter of the cone at the loop location = 0.27021 meters
Hence:
(Diameter of your loop)/(Diameter of the cone at the loop location) = (0.0095493 )/(0.27021 )
=3.5%
in words: the diameter of your loop is only 3.5 per cent of the diameter of the cone at that location.
CONCLUSION: No wonder that you experience practically no resonance. Your loop is way too small, its dimensions do not correspond to the ratio that I advised. Please refer to the images I posted previously. Your loop was dimensioned NOT taking into account my calculations
http://forum.nasaspaceflight.com/index.php?topic=38203.msg1421272#msg1421272
Link: http://forum.nasaspaceflight.com/index.php?topic=38203.msg1419670#msg1419670
real diameter of antenna =(real diameter of cone at that location )*(diameter of red contour region in the plot below)/(diameter of cone at that location in the plot below)
See the images below again, does it look like the red contour is only 3% of the diameter ? NO. The loop you are using is an order of magnitude smaller than what it should be.
(http://forum.nasaspaceflight.com/xindex.php,qaction=dlattach,3Btopic=38203.0,3Battach=1059926,3Bimage.pagespeed.ic.LXpvXL1fCD.webp)
(http://forum.nasaspaceflight.com/xindex.php,qaction=dlattach,3Btopic=38203.0,3Battach=1059928,3Bimage.pagespeed.ic.YHQaUjNJ5z.webp)
I have no idea why you are using the 1/4 free-space wavelength to dimension this loop instead of using the computed wave-patterns.
Use a dual loop on the small end, 180 deg out of phase. See attached.Perfect! This makes a lot of sense Cee, thanks! It also lets the cavity form mode(s) according to the internal dimensions of the cavity walls. The 180 phase shift between the two loops will essentially lock the TE012 mode as well and limit other mode generation if I see this right.
Shell,
Your original sidewall excitation loop design would work as well and probably be easier to implement.
Loop with coaxial feed (Flux-capacitor dimensions from here: http://forum.nasaspaceflight.com/index.php?topic=38203.msg1421269#msg1421269) instead stonehenge ;)I have to watch how I put something through the center as I have this quartz tuning rod right in the middle X_Ray. But it could come right up beside of it. It wouldn't be that hard to do on just the copper plate for a VNA test would it?
Found it. It had been mislabeled in another post as a TE012 and it's a TE013 by EagleWorks, no wonder I was going what the heck.Dr. Rodel how can I compare your images and these of EW and draw any conclusions as to what is happening within the cavity? It's a little confusing.@SeeShellsMy translation of what you wrote is the following:QuoteI'm not sure either of the variable loop sizes as we are trying to excite a TExx mode although EWs was ~λ 14 cm. .55" @2.45GHz.
Someone correct me if I'm wrong, but I seem to recall that EW was working at 1.93 GHz, not 2.45.
@X-Ray - Thanks, I have moved the detector to (.02, .02, (1/4 wl from SE)) that's x,y,z.
@Dr. Rodal -
Freq.= 2.5 GHZ, c= 299792458 m/s
Wl = 0.1199169832 ~= 0.12 meters
Quarter wavelength = 0.03 meters
Frustum meters wave lengths
length 0.1634 1.3616666667
BD 0.295 2.4583333333
SD 0.16 1.3333333333
Taper = 0.8261933905 0.8261933905
Dia @ ¼ wl = 0.2702141983 2.4335475316
Dia of 1/4 wave lengh loop=
Circumference/pi = 0.0095492966 0.0795774715
spelling
Diameter of your loop = 0.0095493 meters
Diameter of the cone at the loop location = 0.27021 meters
Hence:
(Diameter of your loop)/(Diameter of the cone at the loop location) = (0.0095493 )/(0.27021 )
=3.5%
in words: the diameter of your loop is only 3.5 per cent of the diameter of the cone at that location.
CONCLUSION: No wonder that you experience practically no resonance. Your loop is way too small, its dimensions do not correspond to the ratio that I advised. Please refer to the images I posted previously. Your loop was dimensioned NOT taking into account my calculations
http://forum.nasaspaceflight.com/index.php?topic=38203.msg1421272#msg1421272
Link: http://forum.nasaspaceflight.com/index.php?topic=38203.msg1419670#msg1419670
real diameter of antenna =(real diameter of cone at that location )*(diameter of red contour region in the plot below)/(diameter of cone at that location in the plot below)
See the images below again, does it look like the red contour is only 3% of the diameter ? NO. The loop you are using is an order of magnitude smaller than what it should be.
(http://forum.nasaspaceflight.com/xindex.php,qaction=dlattach,3Btopic=38203.0,3Battach=1059926,3Bimage.pagespeed.ic.LXpvXL1fCD.webp)
(http://forum.nasaspaceflight.com/xindex.php,qaction=dlattach,3Btopic=38203.0,3Battach=1059928,3Bimage.pagespeed.ic.YHQaUjNJ5z.webp)
I have no idea why you are using the 1/4 free-space wavelength to dimension this loop instead of using the computed wave-patterns.
This frustum isn't going to be like the first one which was easy to disassemble and I simply would like to get it right on the first shot, well with a good chance anyway.
Thanks,
Shell
Actually, I would go as far as betting:
1) That image
(http://forum.nasaspaceflight.com/xindex.php,qaction=dlattach,3Btopic=38203.0,3Battach=1064549,3Bimage.pagespeed.ic.Rn-aAD0cE2.webp)
is not from NASA or from an electromagnetic field computer program calculation
2) If that image intends to convey an electromagnetic field in the TE012 mode, it is incorrect, as the magnetic polar field in the polar angle direction should look like this:
(http://forum.nasaspaceflight.com/xindex.php,qaction=dlattach,3Btopic=38203.0,3Battach=1059922,3Bimage.pagespeed.ic.O3sFa0O7ox.webp)
3) That image does not correspond to any of the electromagnetic fields in the TE012 mode:
a) it is not an image of the transverse electric field in the azimuthal direction
b) it is not a correct image of the H magnetic field in the spherical polar angle direction
c) it is not an image of the H magnetic field in the longitudinal direction
...
PA Thanks Dr. Rodel! You were right but if is from EW. Now out to the shop. Got a drive to build and as much as I'd love to spend a Saturday chatting with all you great people I have to get booking.
...The image should be traced to its original message to establish who is the author and what are the conditions represented. Does it include dielectric inserts?
Seems to be another document? Please look at the Date and compare them.
Ok - run finished - exciting with only Ex and Ey reduced Q to 6661 and reduced the detected resonant frequency by 10 kHz. And in case I didn't mention it, this is with a 1/4 wave length circumference loop, 1/4 wavelength from the big end and centered.
@aero, is it possible to excite it using an impulse rather than a sinusoid? An impulse will draw out the natural resonance of the cavity, and then we can watch it decay to nothing.
@SeeShellsMy translation of what you wrote is the following:QuoteI'm not sure either of the variable loop sizes as we are trying to excite a TExx mode although EWs was ~λ 14 cm. .55" @2.45GHz.
Someone correct me if I'm wrong, but I seem to recall that EW was working at 1.93 GHz, not 2.45.
@X-Ray - Thanks, I have moved the detector to (.02, .02, (1/4 wl from SE)) that's x,y,z.
@Dr. Rodal -
Freq.= 2.5 GHZ, c= 299792458 m/s
Wl = 0.1199169832 ~= 0.12 meters
Quarter wavelength = 0.03 meters
Frustum meters wave lengths
length 0.1634 1.3616666667
BD 0.295 2.4583333333
SD 0.16 1.3333333333
Taper = 0.8261933905 0.8261933905
Dia @ ¼ wl = 0.2702141983 2.4335475316
Dia of 1/4 wave lengh loop=
Circumference/pi = 0.0095492966 0.0795774715
spelling
Diameter of your loop = 0.0095493 meters
Diameter of the cone at the loop location = 0.27021 meters
Hence:
(Diameter of your loop)/(Diameter of the cone at the loop location) = (0.0095493 )/(0.27021 )
=3.5%
in words: the diameter of your loop is only 3.5 per cent of the diameter of the cone at that location.
CONCLUSION: No wonder that you experience practically no resonance. Your loop is way too small, its dimensions do not correspond to the ratio that I advised. Please refer to the images I posted previously. Your loop was dimensioned NOT taking into account my calculations
http://forum.nasaspaceflight.com/index.php?topic=38203.msg1421272#msg1421272
Link: http://forum.nasaspaceflight.com/index.php?topic=38203.msg1419670#msg1419670
real diameter of antenna =(real diameter of cone at that location )*(diameter of red contour region in the plot below)/(diameter of cone at that location in the plot below)
See the images below again, does it look like the red contour is only 3% of the diameter ? NO. The loop you are using is an order of magnitude smaller than what it should be.
(http://forum.nasaspaceflight.com/xindex.php,qaction=dlattach,3Btopic=38203.0,3Battach=1059926,3Bimage.pagespeed.ic.LXpvXL1fCD.webp)
(http://forum.nasaspaceflight.com/xindex.php,qaction=dlattach,3Btopic=38203.0,3Battach=1059928,3Bimage.pagespeed.ic.YHQaUjNJ5z.webp)
I have no idea why you are using the 1/4 free-space wavelength to dimension this loop instead of using the computed wave-patterns.
Just to let people know there is a small article in the current issue of the New Scientist about Chris Wilson's research into the Casimir effect under the title 'Can We Get Energy From Nothing?'.Well, can we? 8)
...I suggest a loop
Well, maybe Dr. Rodal, its because you don't tell me what loop circumference is, in units of wave length, that you want. In this case, convert meters to wave length by dividing by 0.12 meters/wave length. I don't need to tell you how to do math so please don't make me guess what your pictures mean.
Just to let people know there is a small article in the current issue of the New Scientist about Chris Wilson's research into the Casimir effect under the title 'Can We Get Energy From Nothing?'.Well, can we? 8)
Aero asked me to run a meep simulation using dual dipoles near the big end of the frustum. Results are available in the Google Drive at https://drive.google.com/open?id=0B527OOY4hxdZfmhrZmF3TkdyQlVzTFh4a1hJanc1OGN3OVk0MXRfMk9tc1RoeE5zcll6SGc
In the directory at that link, you'll find copies of the control and log files used, as well as a description ("meep-data-description-CE-2r9-32cy.txt" of the run.
The two dipoles are located 30mm from the big end, and are 0.9 * wave length in size.
Below are some of the more than 400 png images available online that show various aspects of the run. Each png file in the png-directory corresponds to a csv file in the csv-directory with the same base name (that is, without the file extension).
Q reported is -59542171.49652831, so almost 60,000,000.
I'm working to automate more of the production of these sorts of runs, and would appreciate guidance from Dr. Rodal and others on the matter of the png contour representations - whether they're useful or not, and how they might be made more useful. I know there were discussions in the past about useful and less-useful representations, but it's hard for me to draw concrete conclusions from those discussions. Hopefully, we can renew the dialog and arrive at representations that assist in your analysis.
Regards,
Ed
Edit: partial key to file names: tt-[he]aa999, where
tt - time slice
h - magnetic field
e - electric field
aa - two axes such as yx, xz, etc. describing the plane from which the data are drawn
999 - optional slice offset from the big end to the small end through the long axis of the frustum.
big end is 0, small end is 150, antennae are at 30
Aero asked me to run a meep simulation using dual dipoles near the big end of the frustum. Results are available in the Google Drive at https://drive.google.com/open?id=0B527OOY4hxdZfmhrZmF3TkdyQlVzTFh4a1hJanc1OGN3OVk0MXRfMk9tc1RoeE5zcll6SGcJust got in from the shop a bit ago, long day and logged on and saw this work.
In the directory at that link, you'll find copies of the control and log files used, as well as a description ("meep-data-description-CE-2r9-32cy.txt" of the run.
The two dipoles are located 30mm from the big end, and are 0.9 * wave length in size.
Below are some of the more than 400 png images available online that show various aspects of the run. Each png file in the png-directory corresponds to a csv file in the csv-directory with the same base name (that is, without the file extension).
Q reported is -59542171.49652831, so almost 60,000,000.
I'm working to automate more of the production of these sorts of runs, and would appreciate guidance from Dr. Rodal and others on the matter of the png contour representations - whether they're useful or not, and how they might be made more useful. I know there were discussions in the past about useful and less-useful representations, but it's hard for me to draw concrete conclusions from those discussions. Hopefully, we can renew the dialog and arrive at representations that assist in your analysis.
Regards,
Ed
Edit: partial key to file names: tt-[he]aa999, where
tt - time slice
h - magnetic field
e - electric field
aa - two axes such as yx, xz, etc. describing the plane from which the data are drawn
999 - optional slice offset from the big end to the small end through the long axis of the frustum.
big end is 0, small end is 150, antennae are at 30
Maybe this will make some waves 8) But will it hold water?
http://www.science20.com/hammock_physicist/swimming_through_empty_space
http://news.sciencemag.org/2003/02/swimming-through-spacetime
The curvature of spacetime is very slight,
so the ability to swim in spacetime is unlikely
to lead to new propulsion devices. For a
meter-sized object performing meter-sized
deformations at the surface of the Earth, the
displacement is of order 10^(-23) m . Nevertheless,
the effect is interesting as a matter
of principle. You cannot lift yourself by pulling
on your bootstraps, but you can lift yourself
by kicking your heels.
Nevertheless, here is an example of how General Relativity allows propellant-less motion in space.
...
PA Thanks Dr. Rodel! You were right but if is from EW. Now out to the shop. Got a drive to build and as much as I'd love to spend a Saturday chatting with all you great people I have to get booking.
Sorry, but I find this confusing, the image (reproduced now at the left for TE013) is not one I recall from NASA Eagleworks. Is it is something that came from NASA, what is the context in which it was produced? It is also important to establish what are the conditions for the image. Does it include dielectric inserts? What is the natural frequency?
I attach below the original report by Frank Davis (that I am familiar with, that Paul March made available in thread 2) to verify that the image at the left is NOT something that was in the report from NASA that Paul March made available in thread 2
* There are only 27 pages in Frank Davis report, there is no page 28
* There is no TE013 displayed by Frank Davis in his report, as TE013 for the NASA frustum without dielectric has a natural frequency amply exceeding 2.45 GHz
I attach below the image for TE012 that originated with NASA Eagleworks
I would appreciate anybody being able to trace it to its original message, so that we can verify who is the author, and most relevant what are the conditions for that plot
The COMSOL analysis iteration process was used prior to assembly to determine the optimal thickness and diameter of the dielectric RF resonator disc located at the small end of the thruster. The geometry of the RF resonator disc is a function of the resonator material’s relative permittivity, dissipation factor, and target resonance mode.
Interesting are the modes shapes like "TM0(1.5)2" in that document....
PA Thanks Dr. Rodel! You were right but if is from EW. Now out to the shop. Got a drive to build and as much as I'd love to spend a Saturday chatting with all you great people I have to get booking.
Sorry, but I find this confusing, the image (reproduced now at the left for TE013) is not one I recall from NASA Eagleworks. Is it is something that came from NASA, what is the context in which it was produced? It is also important to establish what are the conditions for the image. Does it include dielectric inserts? What is the natural frequency?
I attach below the original report by Frank Davis (that I am familiar with, that Paul March made available in thread 2) to verify that the image at the left is NOT something that was in the report from NASA that Paul March made available in thread 2
* There are only 27 pages in Frank Davis report, there is no page 28
* There is no TE013 displayed by Frank Davis in his report, as TE013 for the NASA frustum without dielectric has a natural frequency amply exceeding 2.45 GHz
I attach below the image for TE012 that originated with NASA Eagleworks
I would appreciate anybody being able to trace it to its original message, so that we can verify who is the author, and most relevant what are the conditions for that plot
All these images come from Eagleworks.
The one you show is indeed from Frank Davies' 2014 progress report, posted by Paul March in this message of the EM Drive Thread 2 (http://forum.nasaspaceflight.com/index.php?topic=36313.msg1333246#msg1333246). The document is entitled "Copper Frustum modes" and the file name is "Frustrum modes overview 2A.pdf". Paper reattached below. TE012 mode is page 18 and calculated for a frequency of 2.1794 GHZ without dielectric. The image shows magnetic H-field vectors in blue and electric E-field vectors in red:
"Without a dielectric" because the caption is 2.1794 GHZ, which is the frustum resonant frequency for this mode, whereas the resonant frequency measured by Eagleworks with 2 PE discs inside was 1.8803 GHz for the same TE012 mode.
See also Eagleworks' 2014 main paper (http://www.libertariannews.org/wp-content/uploads/2014/07/AnomalousThrustProductionFromanRFTestDevice-BradyEtAl.pdf), figure 15 page 12, which also shows TE012 mode with a dielectric:
"With a dielectric" because the text states:QuoteThe COMSOL analysis iteration process was used prior to assembly to determine the optimal thickness and diameter of the dielectric RF resonator disc located at the small end of the thruster. The geometry of the RF resonator disc is a function of the resonator material’s relative permittivity, dissipation factor, and target resonance mode.
You can see the H and E vectors are quite similar with or without a dielectric, for this TE012 mode.
The TE012 mode published by SeeShells and I (along the TE013 version), showing magnetic streamlines in blue, are also from Eagleworks. Those images come from another 2014 report by Davies entitled "Notes on fields in a frustrum type chamber". I can't find where it has been posted the first time (I think by TheTraveller), so I reattach the paper to this message. Whatever I don't understand how streamlines would be a problem instead of field vectors, since streamlines show the path drawn if you link the vectors together, like in a "connecting the dot" game. To me it is the same thing:
Retrieving this file I am shocked to find an important information I didn't see before: those TE/TM modes simulations by Davies (25 March 2014) are based not on Eagleworks' frustum, but Yang's frustum with "proportions estimated from Chinese paper" by Davies!!!!!
Chinese proportions which would be, according to Davies:
Db = L and Ds = Db/2
[...
All these images come from Eagleworks.
....
The TE012 mode published by SeeShells and I (along the TE013 version), showing magnetic streamlines in blue, are also from Eagleworks. Those images come from another 2014 report by Davies entitled "Notes on fields in a frustrum type chamber". I can't find where it has been posted the first time (I think by TheTraveller), so I reattach the paper to this message. Whatever I don't understand how streamlines would be a problem instead of field vectors, since streamlines show the path drawn if you link the vectors together, like in a "connecting the dot" game. To me it is the same thing:...
Whatever I don't understand how streamlines would be a problem instead of field vectors, since streamlines show the path drawn if you link the vectors together, like in a "connecting the dot" game. To me it is the same thing
Since EmDrive is well out on the fringe in any case, one might as well go whole hog and seek to relate all ratios to the Golden Ratio. 8):o 1.618 ::)
Since EmDrive is well out on the fringe in any case, one might as well go whole hog and seek to relate all ratios to the Golden Ratio. 8):o 1.618 ::)
I need to measure this engine first to give you an answer.Since EmDrive is well out on the fringe in any case, one might as well go whole hog and seek to relate all ratios to the Golden Ratio. 8):o 1.618 ::)
So - mystical numerology - applying the golden ratio to the dimensions of a frustum, what harmonic frequency will resonate? Or, inversely, given the golden ratio as a gigahertz frequency, what shape of a frustum will resonate at that frequency?
Inquiring minds want to know ...
Maybe this will make some waves 8) But will it hold water?
http://www.science20.com/hammock_physicist/swimming_through_empty_space
http://news.sciencemag.org/2003/02/swimming-through-spacetime
Here is the original article by Prof. Jack Wisdom (MIT):
http://web.mit.edu/wisdom/www/swimming.pdf
For a meter-sized object performing meter-sized deformations at the surface of the Earth, the
displacement is of order 10^(-23) m
Nevertheless, here is an example of how General Relativity allows propellant-less motion in space.Quote from: Jack WisdomThe curvature of spacetime is very slight,
so the ability to swim in spacetime is unlikely
to lead to new propulsion devices. For a
meter-sized object performing meter-sized
deformations at the surface of the Earth, the
displacement is of order 10^(-23) m . Nevertheless,
the effect is interesting as a matter
of principle. You cannot lift yourself by pulling
on your bootstraps, but you can lift yourself
by kicking your heels.
Maybe this will make some waves 8) But will it hold water?
http://www.science20.com/hammock_physicist/swimming_through_empty_space
http://news.sciencemag.org/2003/02/swimming-through-spacetime
Here is the original article by Prof. Jack Wisdom (MIT):
http://web.mit.edu/wisdom/www/swimming.pdf
For a meter-sized object performing meter-sized deformations at the surface of the Earth, the
displacement is of order 10^(-23) m
Nevertheless, here is an example of how General Relativity allows propellant-less motion in space.Quote from: Jack WisdomThe curvature of spacetime is very slight,
so the ability to swim in spacetime is unlikely
to lead to new propulsion devices. For a
meter-sized object performing meter-sized
deformations at the surface of the Earth, the
displacement is of order 10^(-23) m . Nevertheless,
the effect is interesting as a matter
of principle. You cannot lift yourself by pulling
on your bootstraps, but you can lift yourself
by kicking your heels.
Notice that all the "frame independence absolutists" that like to write ad nauseam about trivial frame-independence, are all of a sudden speechless concerning this paper by an MIT Professor showing that one can actually use General Relativity to swim in space (albeit at an extremely small "stroke" of 10^(-23) m :) )
No need for negative mass !!
No need for Jim Woodward !!
No need for Quantum Vacuum !!
to do this.
What is required is a deformable object (I always noticed that "frame independent absolutists" invariable portray bodies as rigid and isotropic !!! ) and a gravitational field in General Relativity
So much for their "frame independence" absolutism that an astronaut cannot swim in space. So much ink in here and in Reddit has been wasted about "frame-independence" arguments. How do they deal with this counter-example?
Contrary to the "self-appointed experts on frame-independence", General Relativity allows, rather than prevents, swimming in space :)
Here is more: http://physics.stackexchange.com/questions/46180/can-a-deformable-object-swim-in-curved-space-time
At least something makes sense, even if it's a tiny bit of sense and a tiny bit of movement.Maybe this will make some waves 8) But will it hold water?
http://www.science20.com/hammock_physicist/swimming_through_empty_space
http://news.sciencemag.org/2003/02/swimming-through-spacetime
Here is the original article by Prof. Jack Wisdom (MIT):
http://web.mit.edu/wisdom/www/swimming.pdf
For a meter-sized object performing meter-sized deformations at the surface of the Earth, the
displacement is of order 10^(-23) m
Nevertheless, here is an example of how General Relativity allows propellant-less motion in space.Quote from: Jack WisdomThe curvature of spacetime is very slight,
so the ability to swim in spacetime is unlikely
to lead to new propulsion devices. For a
meter-sized object performing meter-sized
deformations at the surface of the Earth, the
displacement is of order 10^(-23) m . Nevertheless,
the effect is interesting as a matter
of principle. You cannot lift yourself by pulling
on your bootstraps, but you can lift yourself
by kicking your heels.
Notice that all the "frame independence absolutists" that like to write ad nauseam about trivial frame-independence, are all of a sudden speechless concerning this paper by an MIT Professor showing that one can actually use General Relativity to swim in space (albeit at an extremely small "stroke" of 10^(-23) m :) )
No need for negative mass !!
No need for Jim Woodward !!
No need for Quantum Vacuum !!
to do this.
What is required is a deformable object (I always noticed that "frame independent absolutists" invariable portray bodies as rigid and isotropic !!! ) and a gravitational field in General Relativity
So much for their "frame independence" absolutism that an astronaut cannot swim in space. So much ink in here and in Reddit has been wasted about "frame-independence" arguments. How do they deal with this counter-example?
Contrary to the "self-appointed experts on frame-independence", General Relativity allows, rather than prevents, swimming in space :)
Here is more: http://physics.stackexchange.com/questions/46180/can-a-deformable-object-swim-in-curved-space-time
Although swimming in spacetime is indeed possible per GR (and it goes much faster close to a black hole event horizon btw ;) ) one still cannot extract useful work from the process. No conservation laws are broken and Queen Emmy (Noether) continues to reign supreme.Aren't we squeezing things up a little like a black hole in the frustum with the wave actions? So it should "Go Faster"? :-\
Although swimming in spacetime is indeed possible per GR (and it goes much faster close to a black hole event horizon btw ;) ) one still cannot extract useful work from the process. No conservation laws are broken and Queen Emmy (Noether) continues to reign supreme.Concerning Noether, she just formalized something that was already known before her. Repeating "Noether" ad nasueam is not informative or clarifying.
Although swimming in spacetime is indeed possible per GR (and it goes much faster close to a black hole event horizon btw ;) ) one still cannot extract useful work from the process. No conservation laws are broken and Queen Emmy (Noether) continues to reign supreme.Concerning Noether, she just formalized something that was already known before her. Repeating "Noether" ad nasueam is not informative or clarifying.
The point is that one can swim in space, all you need is General Relativity.
No "New Physics" are required and the mistake that deniers make is to invoke trivial assumptions of bodies as being rigid and isotropic. They make trivial statements about conservation of Energy and Momentum. Of course they are conserved.
The point is that people making trivial statements about conservation and rigidity state that no motion such as swimming in space is possible, and this has been proven to be incorrect.
.
Here are my test results for evaluating my changes to the loop antenna, measuring in meters and not wavelengths. It turns out that using wave lengths was easy, using meters was easy too, after I calculated the number of wave lengths per meter lengths. I think it is right but here is some data to check. Use 0.3 meters per meep length unit.Give us a gif sequence of Dr. Rodel's antenna. I'll make a animation to see if it evolves the wave patterns correctly.
For frequency ~2.50 GHz, (fsi = 2.495e9) loop parameters are:
start making a loop antenna
Number of points, NP = 283.0
half wave length meep = 0.20026216299265198
loop diameter meep = 0.18
loop circumference meep = 0.5654866776461628
periods around the loop = 1.4118659990377505
meep frequency = 2.496727252558168
Loop antenna created
And for frequency ~ 5.0 GHz (fsi = 4.99e9) loop parameters are:
start making a loop antenna
Number of points, NP = 283.0
half wave length meep = 0.10013108149632599
loop diameter meep = 0.18
loop circumference meep = 0.5654866776461628
periods around the loop = 2.823731998075501
meep frequency = 4.993454505116336
Loop antenna created
Attached are images of the loop at the end of the 3 cycle run.
Plot scale is the same so as you can see, the loop size is independent of wavelength. This is Dr. Rodal's loop, 0.054 meters in diameter. With the fixed circumference in meters, the number of points around the loop depend only on the meep resolution (=250) so are the same in these two runs.
I think it's right. Evaluations?
I found my steampunk magnetron. Love this!
http://www.ebay.com/itm/Rare-Western-Electric-Type-5780-Magnetron-NOS-Radar-Vacuum-Tube-Vintage-JAN-/181609285094?hash=item2a48c1c5e6
I made one more debug run, reducing the resolution from 250 to 100. For frequency ~ 5.0 GHz (fsi = 4.99e9) loop parameters are:Quite an interesting wave pattern.
start making a loop antenna
Number of points, NP = 113.0
half wave length meep = 0.10013108149632599 loop diameter meep = 0.18
loop circumference meep = 0.5654866776461628
periods around the loop = 2.823731998075501
meep frequency = 4.993454505116336
Loop antenna created
If there is a bug maybe I'll see it after I post this.
Unfortunately, the image scales with resolution the number of pixels ratio as 100/250, in this case.
I made one more debug run, reducing the resolution from 250 to 100. For frequency ~ 5.0 GHz (fsi = 4.99e9) loop parameters are:It should be quite interesting to run to see if the large plate position of the loop helps or hinders a TE mode generation. Don't expect a huge Q, EW didn't in their loops.
start making a loop antenna
Number of points, NP = 113.0
half wave length meep = 0.10013108149632599 loop diameter meep = 0.18
loop circumference meep = 0.5654866776461628
periods around the loop = 2.823731998075501
meep frequency = 4.993454505116336
Loop antenna created
If there is a bug maybe I'll see it after I post this.
Unfortunately, the image scales with resolution the number of pixels ratio as 100/250, in this case.
I made one more debug run, reducing the resolution from 250 to 100. For frequency ~ 5.0 GHz (fsi = 4.99e9) loop parameters are:It should be quite interesting to run to see if the large plate position of the loop helps or hinders a TE mode generation. Don't expect a huge Q, EW didn't in their loops.
start making a loop antenna
Number of points, NP = 113.0
half wave length meep = 0.10013108149632599 loop diameter meep = 0.18
loop circumference meep = 0.5654866776461628
periods around the loop = 2.823731998075501
meep frequency = 4.993454505116336
Loop antenna created
If there is a bug maybe I'll see it after I post this.
Unfortunately, the image scales with resolution the number of pixels ratio as 100/250, in this case.
May I ask why we are going with this other software for postprocessing the CSV time slices?
I've been looking at Paraview to do some postprocessing, have you or anyone else here have any feedback on it as a post processor on the csv files?
Today I'm staying out of the lab, need the break and my house needs cleaning, washing done, and I need to cook something other than a TV dinner. Maybe some fried chicken and mashed potatoes with fresh roasted corn on the cob, does a body good.... :D So between loads I'm looking at Paraview.
Shell
I made one more debug run, reducing the resolution from 250 to 100. For frequency ~ 5.0 GHz (fsi = 4.99e9) loop parameters are:Quite an interesting wave pattern.
start making a loop antenna
Number of points, NP = 113.0
half wave length meep = 0.10013108149632599 loop diameter meep = 0.18
loop circumference meep = 0.5654866776461628
periods around the loop = 2.823731998075501
meep frequency = 4.993454505116336
Loop antenna created
If there is a bug maybe I'll see it after I post this.
Unfortunately, the image scales with resolution the number of pixels ratio as 100/250, in this case.
I want to thank you for your work and help.I made one more debug run, reducing the resolution from 250 to 100. For frequency ~ 5.0 GHz (fsi = 4.99e9) loop parameters are:It should be quite interesting to run to see if the large plate position of the loop helps or hinders a TE mode generation. Don't expect a huge Q, EW didn't in their loops.
start making a loop antenna
Number of points, NP = 113.0
half wave length meep = 0.10013108149632599 loop diameter meep = 0.18
loop circumference meep = 0.5654866776461628
periods around the loop = 2.823731998075501
meep frequency = 4.993454505116336
Loop antenna created
If there is a bug maybe I'll see it after I post this.
Unfortunately, the image scales with resolution the number of pixels ratio as 100/250, in this case.
May I ask why we are going with this other software for postprocessing the CSV time slices?
I've been looking at Paraview to do some postprocessing, have you or anyone else here have any feedback on it as a post processor on the csv files?
Today I'm staying out of the lab, need the break and my house needs cleaning, washing done, and I need to cook something other than a TV dinner. Maybe some fried chicken and mashed potatoes with fresh roasted corn on the cob, does a body good.... :D So between loads I'm looking at Paraview.
Shell
I'm working with paraview, too - it's able to read the h5 files directly, if you use a script I've found to create the xdmf descriptor file that tells paraview how to parse the h5 file. Let me know if I can research anything for you with it, and I'll see what I can figure out.
PNG file generation has been problematic due to difficulties figuring out what acceptable scaling factors and contour shape algorithms folks prefer to use. Seems to involve different, and sometimes conflicting, alternatives - tradeoffs between visually appealing, sufficient dynamic range to be able to see different levels and recognize them, and the ability to compare multple related images if they're not scaled the same way ...
Visualization is, I'm convinced, more of a graphic art than a representational science.
Long shot here, but I was reading up on how squeezed light can be generated and I found that one way is via nonlinear frequency mixing. I think I saw evidence of frequency mixing a few months ago by accident. Guess I pretty much have to bust out the test equipment again now to confirm.
http://physics.stackexchange.com/questions/83/how-is-squeezed-light-produced
https://en.wikipedia.org/wiki/Nonlinear_optics#Nonlinear_optical_processes
Anyway, there's some literature out there about using squeezed vacuum for propulsion which is interesting.
http://www.researchgate.net/publication/258317790_Preliminary_Theorectical_Considerations_for_Getting_Thrust_via_Squeezed_Vacuum
http://www.researchgate.net/publication/234887561_Extraction_of_Thrust_from_Quantum_Vacuum_Using_Squeezed_Light
What mode were you trying to get in your frustum?Long shot here, but I was reading up on how squeezed light can be generated and I found that one way is via nonlinear frequency mixing. I think I saw evidence of frequency mixing a few months ago by accident. Guess I pretty much have to bust out the test equipment again now to confirm.
http://physics.stackexchange.com/questions/83/how-is-squeezed-light-produced
https://en.wikipedia.org/wiki/Nonlinear_optics#Nonlinear_optical_processes
Anyway, there's some literature out there about using squeezed vacuum for propulsion which is interesting.
http://www.researchgate.net/publication/258317790_Preliminary_Theorectical_Considerations_for_Getting_Thrust_via_Squeezed_Vacuum
http://www.researchgate.net/publication/234887561_Extraction_of_Thrust_from_Quantum_Vacuum_Using_Squeezed_Light
Results of search for second or third harmonic generation is null. There is no support found for any harmonic generation by the frustum in my possession (no dielectric insert) in the low power regime. Input power was 0dbm.
Screenshot 10 shows spectrum analyzer with sweep generator attached (no frustum in between). Sweeper set from 700-2700mhz (between markers 1&2). Spectrum analyzer span from below cutoff to max range (600-6700mhz). Harmonic generation between markers 3&4 are from the sweeper.
Screenshot 11 shows same but with sweep generator feeding frustum and spectrum analyzer on frustum sample port. Harmonic generation is the same.
So my empty copper can isn't showing any evidence of nonlinear optical behavior. High power remains unexplored. Would be interesting if one could purposely introduce this kind of behavior to see what happens.
Okay... Visuals ... Yuck. Got that. Question though ... Did you look at the folder link, or just the three I attached?I want to thank you for your work and help.I made one more debug run, reducing the resolution from 250 to 100. For frequency ~ 5.0 GHz (fsi = 4.99e9) loop parameters are:It should be quite interesting to run to see if the large plate position of the loop helps or hinders a TE mode generation. Don't expect a huge Q, EW didn't in their loops.
start making a loop antenna
Number of points, NP = 113.0
half wave length meep = 0.10013108149632599 loop diameter meep = 0.18
loop circumference meep = 0.5654866776461628
periods around the loop = 2.823731998075501
meep frequency = 4.993454505116336
Loop antenna created
If there is a bug maybe I'll see it after I post this.
Unfortunately, the image scales with resolution the number of pixels ratio as 100/250, in this case.
May I ask why we are going with this other software for postprocessing the CSV time slices?
I've been looking at Paraview to do some postprocessing, have you or anyone else here have any feedback on it as a post processor on the csv files?
Today I'm staying out of the lab, need the break and my house needs cleaning, washing done, and I need to cook something other than a TV dinner. Maybe some fried chicken and mashed potatoes with fresh roasted corn on the cob, does a body good.... :D So between loads I'm looking at Paraview.
Shell
I'm working with paraview, too - it's able to read the h5 files directly, if you use a script I've found to create the xdmf descriptor file that tells paraview how to parse the h5 file. Let me know if I can research anything for you with it, and I'll see what I can figure out.
PNG file generation has been problematic due to difficulties figuring out what acceptable scaling factors and contour shape algorithms folks prefer to use. Seems to involve different, and sometimes conflicting, alternatives - tradeoffs between visually appealing, sufficient dynamic range to be able to see different levels and recognize them, and the ability to compare multple related images if they're not scaled the same way ...
Visualization is, I'm convinced, more of a graphic art than a representational science.
And sadly (or not) I'm a very visual lady, stupid patterns. ;) Some here are not as much and that's the issue.
I don't particularly care to see the lowest artifacts that meep can generate, especially if it's on a sliding scale, seeing the lowest artifacts make little sense in the frustum. I've been looking for mode generation, traveling modes, and how they decay and where. And especially I'm focused on TE modes. This is why I did the first frustum replicating what I thought was the frustum sizes by Yang and the Chinese, it wasn't the right dimensions we found out. This second is a design of mine focusing on a TE012 mode and there are many modes laying right beside of it well within the envelope of the operating range of the magnetron. I built it to be very stable in thermal expansion issues so I can focus on the interactive modes in the magnetron envelope. I believe it's not one single mode that causes the unique actions but the 5 or so modes right around TE012, it is its nature for this frequency and frustum configuration to not be stable and interact with other modes.
This is what interests me, that shifting interwave mode actions. Dr. Rodel is seeing some of the forces being released in his stress calculations and simply they wouldn't be acting the way they do unless we had a sequence of mode generation and collapse. And in all of this forming and decaying Betty Crocker blender mess are the extraordinary forces of the evanescent waves, so maybe down the line when we have a good looking visual animation we can somehow setup a filter to just look at the evanescent actions in the frustum.
And honestly the current visual well... how do I say... is very yuck.
Anyway thanks for the help and if you wouldn't mind point me to the script for paraview I'd be thankful.
@ShellLet's say I take a 1KHz signal and look at it on the SA, what do I see? A peak at 1KHZ? What if I modulate it? FM or AM or both at the same time? What rolls out of a magnetron? AM and FM and zero of close to point crossovers. It's a beautiful mess of additive and subtractive interference.
Not trying for any specific mode in that test. Just looking for harmonics being generated. But anyway, each of those peaks on the left side of screenshot 11 is a resonance that corresponds to a mode. Which peak is what mode is anybody's guess.
Edit:
It is pretty neat how my mode peaks loosely match up with the mode spectrum from Eagleworks in your pic above. I previously identified two modes, TM212 and TM311(with the help of Rodal *) to use for testing which fall within frequencies that I can generate at home without the help of this whiz bang test equipment.
* http://forum.nasaspaceflight.com/index.php?topic=36313.msg1353372#msg1353372
* http://forum.nasaspaceflight.com/index.php?topic=36313.msg1352878#msg1352878
Anyway thanks for the help and if you wouldn't mind point me to the script for paraview I'd be thankful.
@ShellLet's say I take a 1KHz signal and look at it on the SA, what do I see? A peak at 1KHZ? What if I modulate it? FM or AM or both at the same time? What rolls out of a magnetron? AM and FM and zero of close to point crossovers. It's a beautiful mess of additive and subtractive interference.
Not trying for any specific mode in that test. Just looking for harmonics being generated. But anyway, each of those peaks on the left side of screenshot 11 is a resonance that corresponds to a mode. Which peak is what mode is anybody's guess.
Edit:
It is pretty neat how my mode peaks loosely match up with the mode spectrum from Eagleworks in your pic above. I previously identified two modes, TM212 and TM311(with the help of Rodal *) to use for testing which fall within frequencies that I can generate at home without the help of this whiz bang test equipment.
* http://forum.nasaspaceflight.com/index.php?topic=36313.msg1353372#msg1353372
* http://forum.nasaspaceflight.com/index.php?topic=36313.msg1352878#msg1352878
If I take that 1KHz signal and run it for 16 cycles, but in the center at the 8th cycle flip phases right at the zero cross over point. Insert it into a frustum. Now all of a sudden I've generated a whole line of odd harmonics and little is left of the 1KHZ but if I look at it on the Oscope I'll see the 1KHz and cross over... weird huh?
What I'm trying to say, your harmonics could be buried across the SA sample spectrum and you wouldn't be able to see it on the SA. This is what I'm trying to look for in the varying mode generations within the meep analysis for every mode change there is a frequency and phase shifting more likely introduced by harmonic patterns within the broadband RF into that asymmetrical multi-tuned cavity. Meep is about the only way I can think of seeing them. I guess you could setup a kind of a selective comb filter on the maggie as it's feed into the Waveguide to coax but you also could do a neat thing that X_Ray thought of and setup a trap within the frustum to attenuate the frequencies you didn't want (only after you figured out the ones you wanted) and were causing a heavy loss of Q.
Just throwing out thoughts here.
Shell
PS: The fried chicken and taters and corn were wonderful.
I'd do a simple one first, a square wave will give you components of odd-integer harmonic and then do a sinusoidal and compare the two in your SA.@ShellLet's say I take a 1KHz signal and look at it on the SA, what do I see? A peak at 1KHZ? What if I modulate it? FM or AM or both at the same time? What rolls out of a magnetron? AM and FM and zero of close to point crossovers. It's a beautiful mess of additive and subtractive interference.
Not trying for any specific mode in that test. Just looking for harmonics being generated. But anyway, each of those peaks on the left side of screenshot 11 is a resonance that corresponds to a mode. Which peak is what mode is anybody's guess.
Edit:
It is pretty neat how my mode peaks loosely match up with the mode spectrum from Eagleworks in your pic above. I previously identified two modes, TM212 and TM311(with the help of Rodal *) to use for testing which fall within frequencies that I can generate at home without the help of this whiz bang test equipment.
* http://forum.nasaspaceflight.com/index.php?topic=36313.msg1353372#msg1353372
* http://forum.nasaspaceflight.com/index.php?topic=36313.msg1352878#msg1352878
If I take that 1KHz signal and run it for 16 cycles, but in the center at the 8th cycle flip phases right at the zero cross over point. Insert it into a frustum. Now all of a sudden I've generated a whole line of odd harmonics and little is left of the 1KHZ but if I look at it on the Oscope I'll see the 1KHz and cross over... weird huh?
What I'm trying to say, your harmonics could be buried across the SA sample spectrum and you wouldn't be able to see it on the SA. This is what I'm trying to look for in the varying mode generations within the meep analysis for every mode change there is a frequency and phase shifting more likely introduced by harmonic patterns within the broadband RF into that asymmetrical multi-tuned cavity. Meep is about the only way I can think of seeing them. I guess you could setup a kind of a selective comb filter on the maggie as it's feed into the Waveguide to coax but you also could do a neat thing that X_Ray thought of and setup a trap within the frustum to attenuate the frequencies you didn't want (only after you figured out the ones you wanted) and were causing a heavy loss of Q.
Just throwing out thoughts here.
Shell
PS: The fried chicken and taters and corn were wonderful.
Do you think I should try modulation while looking for harmonic generation? I can do am, fm, 1khz square wave, psk, scalar. Would it be worth it?
Long shot here, but I was reading up on how squeezed light can be generated and I found that one way is via nonlinear frequency mixing. I think I saw evidence of frequency mixing a few months ago by accident. Guess I pretty much have to bust out the test equipment again now to confirm.
http://physics.stackexchange.com/questions/83/how-is-squeezed-light-produced
https://en.wikipedia.org/wiki/Nonlinear_optics#Nonlinear_optical_processes
Anyway, there's some literature out there about using squeezed vacuum for propulsion which is interesting.
http://www.researchgate.net/publication/258317790_Preliminary_Theorectical_Considerations_for_Getting_Thrust_via_Squeezed_Vacuum
http://www.researchgate.net/publication/234887561_Extraction_of_Thrust_from_Quantum_Vacuum_Using_Squeezed_Light
Results of search for second or third harmonic generation is null. There is no support found for any harmonic generation by the frustum in my possession (no dielectric insert) in the low power regime. Input power was 0dbm.
Screenshot 10 shows spectrum analyzer with sweep generator attached (no frustum in between). Sweeper set from 700-2700mhz (between markers 1&2). Spectrum analyzer span from well below frustum cutoff to max range of gear (600-6700mhz). Harmonic generation between markers 3&4 are from the sweeper.
Screenshot 11 shows same but with sweep generator feeding frustum and spectrum analyzer on frustum sample port. Harmonic generation is the same.
So my empty copper can isn't showing any evidence of nonlinear optical behavior. High power remains unexplored. Would be interesting if one could purposely introduce this kind of behavior to see what happens.
The work of Puthoff, Joe Depp, Riccardo Storti and myself, have resolved these issues with PV by 2005. The PV warp drive is frame dragging in PV just as it is in GR. It turns out that the metric coefficients of GR are "equivalent" to a variable refractive index tensor, composed of QV interactions with matter.
What I have come to understand clearly, is that the differences between PV and GR are simply a matter of how one interprets the math. Space-time curvature of empty vacuum VS interactions of matter with the QV. I have developed a Quantum model for PV that works well enough for engineering purposes. If even 1 millionth of the work done in the name of GR were done for PV, all this would be obvious and text book trivia, but history has lead thousands of people to work on GR. Where, only a handful of mostly engineers have even grasped the power of PV as a foundation for understanding GR. More people should study it, as it really does lead to new ideas that fit within the GR framework, simply by re-interpreting the physical interaction of matter & metric.
FYI: I am still waiting for JBIS to give me any review or comments on my Electromagnetic Quantum Vacuum Warp Drive paper that I submitted last January. Which shows how the QV model of PV is used to re-interpret GR and better understand what is needed to go FTL. You can find related work on my RG page.
Todd
Can PV make any experimentally verifiable predictions different to those made by mainstream physics, that would earn it a place at the table? I think not, otherwise it would be big news....
Now I agree with you that the Puthof's Polarizable Vacuum theory cannot be a replacement for General Relativity and its endorsement of Mach (not March ! ;)) intuition on the origin of inertia. It was also; I would say; the view of Puthof himself who clearly wrote in 1999 that the Polarizable Vacuum theory was not yet in a positon to explain both gravitational radiation and frame-dragging effects (base of Mach ideas on inertia incorporation in General Relativity).
The work of Puthoff, Joe Depp, Riccardo Storti and myself, have resolved these issues with PV by 2005. The PV warp drive is frame dragging in PV just as it is in GR. It turns out that the metric coefficients of GR are "equivalent" to a variable refractive index tensor, composed of QV interactions with matter.
What I have come to understand clearly, is that the differences between PV and GR are simply a matter of how one interprets the math. Space-time curvature of empty vacuum VS interactions of matter with the QV. I have developed a Quantum model for PV that works well enough for engineering purposes. If even 1 millionth of the work done in the name of GR were done for PV, all this would be obvious and text book trivia, but history has lead thousands of people to work on GR. Where, only a handful of mostly engineers have even grasped the power of PV as a foundation for understanding GR. More people should study it, as it really does lead to new ideas that fit within the GR framework, simply by re-interpreting the physical interaction of matter & metric.
FYI: I am still waiting for JBIS to give me any review or comments on my Electromagnetic Quantum Vacuum Warp Drive paper that I submitted last January. Which shows how the QV model of PV is used to re-interpret GR and better understand what is needed to go FTL. You can find related work on my RG page.
Todd
Prof. Dr. James Woodward, it is my understanding, is of the opinion that the only way that any propulsion out of the EM Drive could be justified using his Machian theory is if the EM Drive contains a dielectric insert as used by NASA in their experiments.
Therefore, the experiments performed by RFMWGUY, as well as the latest experiments and designs of Shaywer, and the experiments of Yang and Tajmar, for example cannot result in space propulsion according to Prof. Woodward's theory since all these experiments do not include any dielectric insert. Prof. Woodward, as I understand it, maintains that an EM Drive tested without a dielectric insert cannot obtain any thrust whatsoever for space propulsion because such thrust is precluded by what Prof. Woodward calls "THE LAW" in capital letters: the law of conservation of momentum.
Prof. Dr. James Woodward, ...
I think you have not yet discussed these matters with Prof. Woodward, to seek his opinion on whether he agrees with your rendition of his theory for Shawyer's EM Drive without a dielectric.Prof. Dr. James Woodward, it is my understanding, is of the opinion that the only way that any propulsion out of the EM Drive could be justified using his Machian theory is if the EM Drive contains a dielectric insert as used by NASA in their experiments.
Therefore, the experiments performed by RFMWGUY, as well as the latest experiments and designs of Shaywer, and the experiments of Yang and Tajmar, for example cannot result in space propulsion according to Prof. Woodward's theory since all these experiments do not include any dielectric insert. Prof. Woodward, as I understand it, maintains that an EM Drive tested without a dielectric insert cannot obtain any thrust whatsoever for space propulsion because such thrust is precluded by what Prof. Woodward calls "THE LAW" in capital letters: the law of conservation of momentum.
I think your statements are too much dogmatic....
I think you have not yet discussed these matters with Prof. Woodward, to seek his opinion on whether he agrees with your rendition of his theory for Shawyer's EM Drive without a dielectric.Oh but I am not in a position to propose a theory explaining the EMDrive phenomena. I am just looking for the possible differences between successful experiments (Shawyer, Chinese, German ...) and other non conclusive experiments based on the same principle. The idea to look for the presence or not of the second harmonic is an empirical borrow to the approach of Woodward. I have nothing against the use of dielectric in RF cavities design, but it seems well that some successful experiments don't need dielectric to give measurable thrust. So other(s) parameter(s) should be looked for to explain the differences between supposed honest test results.
Back from a short break...nope...I will not make a comment about an EM Vortex looking pattern ;)I made one more debug run, reducing the resolution from 250 to 100. For frequency ~ 5.0 GHz (fsi = 4.99e9) loop parameters are:Quite an interesting wave pattern.
start making a loop antenna
Number of points, NP = 113.0
half wave length meep = 0.10013108149632599 loop diameter meep = 0.18
loop circumference meep = 0.5654866776461628
periods around the loop = 2.823731998075501
meep frequency = 4.993454505116336
Loop antenna created
If there is a bug maybe I'll see it after I post this.
Unfortunately, the image scales with resolution the number of pixels ratio as 100/250, in this case.
Fair enough, but I am still in the mode of eliminating faulty results such as thermal lift and getting higher resolution on downward movement. This will take some time and $$. once measurement is where I want it, I move back to the frustum. First, characterize resonance and tune for 2.45ghz if needed. A dielectric will help tune, but it could also induce movement based on outgassing at high temp. Recall EW melted some plastic hardware during testing. Guess dielectric pucks are one of my last mods to consider.I think you have not yet discussed these matters with Prof. Woodward, to seek his opinion on whether he agrees with your rendition of his theory for Shawyer's EM Drive without a dielectric.Oh but I am not in a position to propose a theory explaining the EMDrive phenomena. I am just looking for the possible differences between successful experiments (Shawyer, Chinese, German ...) and other non conclusive experiments based on the same principle. The idea to look for the presence or not of the second harmonic is an empirical borrow to the approach of Woodward. I have nothing against the use of dielectric in RF cavities design, but it seems well that some successful experiments don't need dielectric to give measurable thrust. So other(s) parameter(s) should be looked for to explain the differences between supposed honest test results.
Back from a short break...nope...I will not make a comment about an EM Vortex looking pattern ;)I made one more debug run, reducing the resolution from 250 to 100. For frequency ~ 5.0 GHz (fsi = 4.99e9) loop parameters are:Quite an interesting wave pattern.
start making a loop antenna
Number of points, NP = 113.0
half wave length meep = 0.10013108149632599 loop diameter meep = 0.18
loop circumference meep = 0.5654866776461628
periods around the loop = 2.823731998075501
meep frequency = 4.993454505116336
Loop antenna created
If there is a bug maybe I'll see it after I post this.
Unfortunately, the image scales with resolution the number of pixels ratio as 100/250, in this case.
Back from a short break...nope...I will not make a comment about an EM Vortex looking pattern ;)I made one more debug run, reducing the resolution from 250 to 100. For frequency ~ 5.0 GHz (fsi = 4.99e9) loop parameters are:Quite an interesting wave pattern.
start making a loop antenna
Number of points, NP = 113.0
half wave length meep = 0.10013108149632599 loop diameter meep = 0.18
loop circumference meep = 0.5654866776461628
periods around the loop = 2.823731998075501
meep frequency = 4.993454505116336
Loop antenna created
If there is a bug maybe I'll see it after I post this.
Unfortunately, the image scales with resolution the number of pixels ratio as 100/250, in this case.
heheheh, you with me big guy? So you like the loop?
Shell
... The meep line source is not a dipole at all. It is a line with all points simultaneously excited. In the real world, electric charge moving in a wire radiate fields as the charge moves to and fro, there is nothing simultaneous about it on that scale.... I'll speculate that meep will calculate much lower Q values when the cavity is excited by a model of a real-world antenna...Are you planning to run a "model of a real world" straight antenna for comparison with the "Meep line source"?
Can PV make any experimentally verifiable predictions different to those made by mainstream physics, that would earn it a place at the table? I think not, otherwise it would be big news....
Now I agree with you that the Puthof's Polarizable Vacuum theory cannot be a replacement for General Relativity and its endorsement of Mach (not March ! ;)) intuition on the origin of inertia. It was also; I would say; the view of Puthof himself who clearly wrote in 1999 that the Polarizable Vacuum theory was not yet in a positon to explain both gravitational radiation and frame-dragging effects (base of Mach ideas on inertia incorporation in General Relativity).
The work of Puthoff, Joe Depp, Riccardo Storti and myself, have resolved these issues with PV by 2005. The PV warp drive is frame dragging in PV just as it is in GR. It turns out that the metric coefficients of GR are "equivalent" to a variable refractive index tensor, composed of QV interactions with matter.
What I have come to understand clearly, is that the differences between PV and GR are simply a matter of how one interprets the math. Space-time curvature of empty vacuum VS interactions of matter with the QV. I have developed a Quantum model for PV that works well enough for engineering purposes. If even 1 millionth of the work done in the name of GR were done for PV, all this would be obvious and text book trivia, but history has lead thousands of people to work on GR. Where, only a handful of mostly engineers have even grasped the power of PV as a foundation for understanding GR. More people should study it, as it really does lead to new ideas that fit within the GR framework, simply by re-interpreting the physical interaction of matter & metric.
FYI: I am still waiting for JBIS to give me any review or comments on my Electromagnetic Quantum Vacuum Warp Drive paper that I submitted last January. Which shows how the QV model of PV is used to re-interpret GR and better understand what is needed to go FTL. You can find related work on my RG page.
Todd
The work of Puthoff, Joe Depp, Riccardo Storti and myself, have resolved these issues with PV by 2005. The PV warp drive is frame dragging in PV just as it is in GR. It turns out that the metric coefficients of GR are "equivalent" to a variable refractive index tensor, composed of QV interactions with matter.
What I have come to understand clearly, is that the differences between PV and GR are simply a matter of how one interprets the math. Space-time curvature of empty vacuum VS interactions of matter with the QV. I have developed a Quantum model for PV that works well enough for engineering purposes. If even 1 millionth of the work done in the name of GR were done for PV, all this would be obvious and text book trivia, but history has lead thousands of people to work on GR. Where, only a handful of mostly engineers have even grasped the power of PV as a foundation for understanding GR. More people should study it, as it really does lead to new ideas that fit within the GR framework, simply by re-interpreting the physical interaction of matter & metric.
FYI: I am still waiting for JBIS to give me any review or comments on my Electromagnetic Quantum Vacuum Warp Drive paper that I submitted last January. Which shows how the QV model of PV is used to re-interpret GR and better understand what is needed to go FTL. You can find related work on my RG page.
Todd
Thanks very much for the information. Do you refer to the articles:"Polarizable Vacuum (PV) and the Schwarzschild Solution", "Polarizable Vacuum and the Reissner-Nordstrom Solution" ?
Are these Schwarzschild and Reissner-Nordstrom Solutions compatible with the need of an horizon of causality for the Transactional interpretation of instantaneous action of Inertia Force ( “advanced” wave propagating backward in time) ?
... The meep line source is not a dipole at all. It is a line with all points simultaneously excited. In the real world, electric charge moving in a wire radiate fields as the charge moves to and fro, there is nothing simultaneous about it on that scale.... I'll speculate that meep will calculate much lower Q values when the cavity is excited by a model of a real-world antenna...Are you planning to run a "model of a real world" straight antenna for comparison with the "Meep line source"?
Yes, but I did ask for something experimentally verifiable. If everything, including our measuring sticks, is changing then how could we know? Can you devise any experiment to test any of PV's unique predictions?Can PV make any experimentally verifiable predictions different to those made by mainstream physics, that would earn it a place at the table? I think not, otherwise it would be big news....
Now I agree with you that the Puthof's Polarizable Vacuum theory cannot be a replacement for General Relativity and its endorsement of Mach (not March ! ;)) intuition on the origin of inertia. It was also; I would say; the view of Puthof himself who clearly wrote in 1999 that the Polarizable Vacuum theory was not yet in a positon to explain both gravitational radiation and frame-dragging effects (base of Mach ideas on inertia incorporation in General Relativity).
The work of Puthoff, Joe Depp, Riccardo Storti and myself, have resolved these issues with PV by 2005. The PV warp drive is frame dragging in PV just as it is in GR. It turns out that the metric coefficients of GR are "equivalent" to a variable refractive index tensor, composed of QV interactions with matter.
What I have come to understand clearly, is that the differences between PV and GR are simply a matter of how one interprets the math. Space-time curvature of empty vacuum VS interactions of matter with the QV. I have developed a Quantum model for PV that works well enough for engineering purposes. If even 1 millionth of the work done in the name of GR were done for PV, all this would be obvious and text book trivia, but history has lead thousands of people to work on GR. Where, only a handful of mostly engineers have even grasped the power of PV as a foundation for understanding GR. More people should study it, as it really does lead to new ideas that fit within the GR framework, simply by re-interpreting the physical interaction of matter & metric.
FYI: I am still waiting for JBIS to give me any review or comments on my Electromagnetic Quantum Vacuum Warp Drive paper that I submitted last January. Which shows how the QV model of PV is used to re-interpret GR and better understand what is needed to go FTL. You can find related work on my RG page.
Todd
Hypothetically, it predicts that the Hubble expansion "red shift" could be (partly) due to our rulers contracting as the universe runs out of energy. All it takes is for 1 meter to contract by 6.8 nanometers/century, as the driving power of the ZPF runs down in the present, relative to the distant past we view through our telescope, to account for the Hubble expansion.
Todd
Yes, but I did ask for something experimentally verifiable. If everything, including our measuring sticks, is changing then how could we know? Can you devise any experiment to test any of PV's unique predictions?Can PV make any experimentally verifiable predictions different to those made by mainstream physics, that would earn it a place at the table? I think not, otherwise it would be big news....
Now I agree with you that the Puthof's Polarizable Vacuum theory cannot be a replacement for General Relativity and its endorsement of Mach (not March ! ;)) intuition on the origin of inertia. It was also; I would say; the view of Puthof himself who clearly wrote in 1999 that the Polarizable Vacuum theory was not yet in a positon to explain both gravitational radiation and frame-dragging effects (base of Mach ideas on inertia incorporation in General Relativity).
The work of Puthoff, Joe Depp, Riccardo Storti and myself, have resolved these issues with PV by 2005. The PV warp drive is frame dragging in PV just as it is in GR. It turns out that the metric coefficients of GR are "equivalent" to a variable refractive index tensor, composed of QV interactions with matter.
What I have come to understand clearly, is that the differences between PV and GR are simply a matter of how one interprets the math. Space-time curvature of empty vacuum VS interactions of matter with the QV. I have developed a Quantum model for PV that works well enough for engineering purposes. If even 1 millionth of the work done in the name of GR were done for PV, all this would be obvious and text book trivia, but history has lead thousands of people to work on GR. Where, only a handful of mostly engineers have even grasped the power of PV as a foundation for understanding GR. More people should study it, as it really does lead to new ideas that fit within the GR framework, simply by re-interpreting the physical interaction of matter & metric.
FYI: I am still waiting for JBIS to give me any review or comments on my Electromagnetic Quantum Vacuum Warp Drive paper that I submitted last January. Which shows how the QV model of PV is used to re-interpret GR and better understand what is needed to go FTL. You can find related work on my RG page.
Todd
Hypothetically, it predicts that the Hubble expansion "red shift" could be (partly) due to our rulers contracting as the universe runs out of energy. All it takes is for 1 meter to contract by 6.8 nanometers/century, as the driving power of the ZPF runs down in the present, relative to the distant past we view through our telescope, to account for the Hubble expansion.
Todd
Yes, but I did ask for something experimentally verifiable. If everything, including our measuring sticks, is changing then how could we know? Can you devise any experiment to test any of PV's unique predictions?Can PV make any experimentally verifiable predictions different to those made by mainstream physics, that would earn it a place at the table? I think not, otherwise it would be big news....
Now I agree with you that the Puthof's Polarizable Vacuum theory cannot be a replacement for General Relativity and its endorsement of Mach (not March ! ;)) intuition on the origin of inertia. It was also; I would say; the view of Puthof himself who clearly wrote in 1999 that the Polarizable Vacuum theory was not yet in a positon to explain both gravitational radiation and frame-dragging effects (base of Mach ideas on inertia incorporation in General Relativity).
The work of Puthoff, Joe Depp, Riccardo Storti and myself, have resolved these issues with PV by 2005. The PV warp drive is frame dragging in PV just as it is in GR. It turns out that the metric coefficients of GR are "equivalent" to a variable refractive index tensor, composed of QV interactions with matter.
What I have come to understand clearly, is that the differences between PV and GR are simply a matter of how one interprets the math. Space-time curvature of empty vacuum VS interactions of matter with the QV. I have developed a Quantum model for PV that works well enough for engineering purposes. If even 1 millionth of the work done in the name of GR were done for PV, all this would be obvious and text book trivia, but history has lead thousands of people to work on GR. Where, only a handful of mostly engineers have even grasped the power of PV as a foundation for understanding GR. More people should study it, as it really does lead to new ideas that fit within the GR framework, simply by re-interpreting the physical interaction of matter & metric.
FYI: I am still waiting for JBIS to give me any review or comments on my Electromagnetic Quantum Vacuum Warp Drive paper that I submitted last January. Which shows how the QV model of PV is used to re-interpret GR and better understand what is needed to go FTL. You can find related work on my RG page.
Todd
Hypothetically, it predicts that the Hubble expansion "red shift" could be (partly) due to our rulers contracting as the universe runs out of energy. All it takes is for 1 meter to contract by 6.8 nanometers/century, as the driving power of the ZPF runs down in the present, relative to the distant past we view through our telescope, to account for the Hubble expansion.
Todd
The thing is, it is not unique. I can predict the same thing using GR, resulting from variation of the metric coefficient. So it wouldn't solve anything. Again, PV is simply an alternative interpretation of GR. The math is identical, so the predictions are also identical. Until we have a verifiable "accepted" model of Quantum Gravity, both PV and GR are classical theories which are complimentary interpretations of the observable data. My QG model, is an engineering tool that works within the parameters I need it to work. That's all.
Todd
Then PV is an empty suit. GR can do it all.
Yes, but I did ask for something experimentally verifiable. If everything, including our measuring sticks, is changing then how could we know? Can you devise any experiment to test any of PV's unique predictions?Can PV make any experimentally verifiable predictions different to those made by mainstream physics, that would earn it a place at the table? I think not, otherwise it would be big news....
Now I agree with you that the Puthof's Polarizable Vacuum theory cannot be a replacement for General Relativity and its endorsement of Mach (not March ! ;)) intuition on the origin of inertia. It was also; I would say; the view of Puthof himself who clearly wrote in 1999 that the Polarizable Vacuum theory was not yet in a positon to explain both gravitational radiation and frame-dragging effects (base of Mach ideas on inertia incorporation in General Relativity).
The work of Puthoff, Joe Depp, Riccardo Storti and myself, have resolved these issues with PV by 2005. The PV warp drive is frame dragging in PV just as it is in GR. It turns out that the metric coefficients of GR are "equivalent" to a variable refractive index tensor, composed of QV interactions with matter.
What I have come to understand clearly, is that the differences between PV and GR are simply a matter of how one interprets the math. Space-time curvature of empty vacuum VS interactions of matter with the QV. I have developed a Quantum model for PV that works well enough for engineering purposes. If even 1 millionth of the work done in the name of GR were done for PV, all this would be obvious and text book trivia, but history has lead thousands of people to work on GR. Where, only a handful of mostly engineers have even grasped the power of PV as a foundation for understanding GR. More people should study it, as it really does lead to new ideas that fit within the GR framework, simply by re-interpreting the physical interaction of matter & metric.
FYI: I am still waiting for JBIS to give me any review or comments on my Electromagnetic Quantum Vacuum Warp Drive paper that I submitted last January. Which shows how the QV model of PV is used to re-interpret GR and better understand what is needed to go FTL. You can find related work on my RG page.
Todd
Hypothetically, it predicts that the Hubble expansion "red shift" could be (partly) due to our rulers contracting as the universe runs out of energy. All it takes is for 1 meter to contract by 6.8 nanometers/century, as the driving power of the ZPF runs down in the present, relative to the distant past we view through our telescope, to account for the Hubble expansion.
Todd
The thing is, it is not unique. I can predict the same thing using GR, resulting from variation of the metric coefficient. So it wouldn't solve anything. Again, PV is simply an alternative interpretation of GR. The math is identical, so the predictions are also identical. Until we have a verifiable "accepted" model of Quantum Gravity, both PV and GR are classical theories which are complimentary interpretations of the observable data. My QG model, is an engineering tool that works within the parameters I need it to work. That's all.
Todd
Yes, but I did ask for something experimentally verifiable. If everything, including our measuring sticks, is changing then how could we know? Can you devise any experiment to test any of PV's unique predictions?Can PV make any experimentally verifiable predictions different to those made by mainstream physics, that would earn it a place at the table? I think not, otherwise it would be big news....
Now I agree with you that the Puthof's Polarizable Vacuum theory cannot be a replacement for General Relativity and its endorsement of Mach (not March ! ;)) intuition on the origin of inertia. It was also; I would say; the view of Puthof himself who clearly wrote in 1999 that the Polarizable Vacuum theory was not yet in a positon to explain both gravitational radiation and frame-dragging effects (base of Mach ideas on inertia incorporation in General Relativity).
The work of Puthoff, Joe Depp, Riccardo Storti and myself, have resolved these issues with PV by 2005. The PV warp drive is frame dragging in PV just as it is in GR. It turns out that the metric coefficients of GR are "equivalent" to a variable refractive index tensor, composed of QV interactions with matter.
What I have come to understand clearly, is that the differences between PV and GR are simply a matter of how one interprets the math. Space-time curvature of empty vacuum VS interactions of matter with the QV. I have developed a Quantum model for PV that works well enough for engineering purposes. If even 1 millionth of the work done in the name of GR were done for PV, all this would be obvious and text book trivia, but history has lead thousands of people to work on GR. Where, only a handful of mostly engineers have even grasped the power of PV as a foundation for understanding GR. More people should study it, as it really does lead to new ideas that fit within the GR framework, simply by re-interpreting the physical interaction of matter & metric.
FYI: I am still waiting for JBIS to give me any review or comments on my Electromagnetic Quantum Vacuum Warp Drive paper that I submitted last January. Which shows how the QV model of PV is used to re-interpret GR and better understand what is needed to go FTL. You can find related work on my RG page.
Todd
Hypothetically, it predicts that the Hubble expansion "red shift" could be (partly) due to our rulers contracting as the universe runs out of energy. All it takes is for 1 meter to contract by 6.8 nanometers/century, as the driving power of the ZPF runs down in the present, relative to the distant past we view through our telescope, to account for the Hubble expansion.
Todd
The thing is, it is not unique. I can predict the same thing using GR, resulting from variation of the metric coefficient. So it wouldn't solve anything. Again, PV is simply an alternative interpretation of GR. The math is identical, so the predictions are also identical. Until we have a verifiable "accepted" model of Quantum Gravity, both PV and GR are classical theories which are complimentary interpretations of the observable data. My QG model, is an engineering tool that works within the parameters I need it to work. That's all.
Todd
Prof. Wisdom proved that an astronaut can swim in space just by using his arms (albeit with an extremely small stroke) using General Relativity. Can the Puthoff PV theory show the same result ? (that an astronaut can swim in space just by using his arms)
A good referance aero.Back from a short break...nope...I will not make a comment about an EM Vortex looking pattern ;)I made one more debug run, reducing the resolution from 250 to 100. For frequency ~ 5.0 GHz (fsi = 4.99e9) loop parameters are:Quite an interesting wave pattern.
start making a loop antenna
Number of points, NP = 113.0
half wave length meep = 0.10013108149632599 loop diameter meep = 0.18
loop circumference meep = 0.5654866776461628
periods around the loop = 2.823731998075501
meep frequency = 4.993454505116336
Loop antenna created
If there is a bug maybe I'll see it after I post this.
Unfortunately, the image scales with resolution the number of pixels ratio as 100/250, in this case.
heheheh, you with me big guy? So you like the loop?
Shell
Before I get to my point, I thought I'd just mention a misspeak in the above. With h5topng images, the number of pixels ratio go with resolution as (100/250)2 since the image is 2 dimensional. (For resolution going from 250 to 100.)
Now, the image is correct. Much clearer images will be forthcoming. The field patterns spiral out from the loop because electricity flows around the loop at a finite speed creating fields as it flows. This same characteristic is true for dipole antennas although not true for a meep simulated line source that I have been calling a dipole. The meep line source is not a dipole at all. It is a line with all points simultaneously excited. In the real world, electric charge moving in a wire radiate fields as the charge moves to and fro, there is nothing simultaneous about it on that scale.
That means that we need to think again about what previous meep data actually means and the difference in the EM field excitation patterns between antennas and wave guides. I'll speculate that meep will calculate much lower Q values when the cavity is excited by a model of a real-world antenna.
You all know more antenna theory than I do, but for the uninformed like me, here is an easy example -reference.
http://electronics.stackexchange.com/questions/73998/how-antenna-radiateshow-currents-flows-through-wire (http://electronics.stackexchange.com/questions/73998/how-antenna-radiateshow-currents-flows-through-wire)
The fact that March is a co-author of this article is interesting as he is himself willing to found an explanation of the Shawyer's EMDrive in term of Woodward's work:
The thing is, it is not unique. I can predict the same thing using GR, resulting from variation of the metric coefficient. So it wouldn't solve anything. Again, PV is simply an alternative interpretation of GR. The math is identical, so the predictions are also identical. Until we have a verifiable "accepted" model of Quantum Gravity, both PV and GR are classical theories which are complimentary interpretations of the observable data. My QG model, is an engineering tool that works within the parameters I need it to work. That's all.
Todd
Prof. Wisdom proved that an astronaut can swim in space just by using his arms (albeit with an extremely small stroke) using General Relativity. Can the Puthoff PV theory show the same result ? (that an astronaut can swim in space just by using his arms)
I am feeling a bit of excitement as, I suspect, I have convinced myself that (that I know what I am talking about) and that there is a method that (I have discussed earlier) that would work for electromagnetic propulsion. It is describable, fairly simple, and it should be possible to convince others in the field. Some time was needed to convince myself but I now understand a bit better why it should work. The forces should be as large as two magnets attracting if done right but the forces should point in the same direction (unidirectional). This should work if only one of the opposing force is eliminated (static electric or magnetic). It isn't exactly Shawer's EM drive but as we don't yet fully understand his drive I suspect there is a remote possibility it could be related. Then again maybe other theoretical effects would be related too.
There should be an advantage to using the simplicity of cylindrical cavities I suspect and this method does that (simplicity in understanding). There also appears to be a simple way of tuning and even controlling the phase inside the cavities. Should I continue to elaborate or is the general consensus that it is impossible?
It does depend on there being a light-speed limit to information, and if we can't agree on that then I am not sure it would work.
I am feeling a bit of excitement as, I suspect, I have convinced myself that (that I know what I am talking about) and that there is a method that (I have discussed earlier) that would work for electromagnetic propulsion. It is describable, fairly simple, and it should be possible to convince others in the field. Some time was needed to convince myself but I now understand a bit better why it should work. The forces should be as large as two magnets attracting if done right but the forces should point in the same direction (unidirectional). This should work if only one of the opposing force is eliminated (static electric or magnetic). It isn't exactly Shawer's EM drive but as we don't yet fully understand his drive I suspect there is a remote possibility it could be related. Then again maybe other theoretical effects would be related too.
There should be an advantage to using the simplicity of cylindrical cavities I suspect and this method does that (simplicity in understanding). There also appears to be a simple way of tuning and even controlling the phase inside the cavities. Should I continue to elaborate or is the general consensus that it is impossible?
It does depend on there being a light-speed limit to information, and if we can't agree on that then I am not sure it would work.
Have you worked out the full integral of the Maxwell force density? Where all values of E & H are functions of x,y,z,t and t-t' retarded fields, in whatever coordinates you choose. Then integrate that over the volume of both halves. If you are left with a non-zero result, then you could convince anyone. Without that, we're in the same boat.
Todd
{snip}
I have constructed the holes so as to retain as much as possible of the rotational and other symmetries of the walls of the frustrum. It may already be obvious to others, but I found it interesting to note that if a mesh frustrum were constructed in the obvious way, by rolling up and joining a flat piece of regularly spaced mesh, the frustrum loses its rotational symmetry. Aside from the seam (!) the holes are not in the right places. If the mesh actually does affect the fields inside the frustrum, it might therefore be doing so in a way which impacts field symmetries.
Regards,
R.
CAUTION: Nobody has yet shown (either theoretically, numerically or experimentally) that the small holes in RFMWGUY's build affect anything related to electromagnetic resonance. On the contrary, a number of theoretical and experimental studies previously discussed in the thread point out that such small holes as used in RFMWGUY's build should NOT affect resonance at the experimental frequency (2.45GHz).{snip}
I have constructed the holes so as to retain as much as possible of the rotational and other symmetries of the walls of the frustrum. It may already be obvious to others, but I found it interesting to note that if a mesh frustrum were constructed in the obvious way, by rolling up and joining a flat piece of regularly spaced mesh, the frustrum loses its rotational symmetry. Aside from the seam (!) the holes are not in the right places. If the mesh actually does affect the fields inside the frustrum, it might therefore be doing so in a way which impacts field symmetries.
Regards,
R.
So a 3D manufacturing process may be a better way to make the frustrum.
CAUTION: Nobody has yet shown (either theoretically, numerically or experimentally) that the small holes in RFMWGUY's build affect anything related to electromagnetic resonance. On the contrary, a number of theoretical and experimental studies previously discussed in the thread point out that such small holes as used in RFMWGUY's build should NOT affect resonance at the experimental frequency (2.45GHz).{snip}
I have constructed the holes so as to retain as much as possible of the rotational and other symmetries of the walls of the frustrum. It may already be obvious to others, but I found it interesting to note that if a mesh frustrum were constructed in the obvious way, by rolling up and joining a flat piece of regularly spaced mesh, the frustrum loses its rotational symmetry. Aside from the seam (!) the holes are not in the right places. If the mesh actually does affect the fields inside the frustrum, it might therefore be doing so in a way which impacts field symmetries.
Regards,
R.
So a 3D manufacturing process may be a better way to make the frustrum.
What is known to strongly affect resonance, (as has been shown previously theoretically, numerically and experimentally) is the RF feed: whether by antenna (shape and placement of the antenna(s)) or by waveguide (shape and placement of waveguide).
Thus aero's time seems to be well directed and prioritized: towards modeling the antenna rather than the holes.
Actually, once aero has modelled loop antennas, the next suggested step should be to model RF feed through waveguide(s) (shape and placement of waveguide).
The thing is, it is not unique. I can predict the same thing using GR, resulting from variation of the metric coefficient. So it wouldn't solve anything. Again, PV is simply an alternative interpretation of GR. The math is identical, so the predictions are also identical. Until we have a verifiable "accepted" model of Quantum Gravity, both PV and GR are classical theories which are complimentary interpretations of the observable data. My QG model, is an engineering tool that works within the parameters I need it to work. That's all.
Todd
Prof. Wisdom proved that an astronaut can swim in space just by using his arms (albeit with an extremely small stroke) using General Relativity. Can the Puthoff PV theory show the same result ? (that an astronaut can swim in space just by using his arms)
Someone will also have to design a very small machine to test General Relativity by swimming.
If it works I wonder if it can be turned into a practical method of space propulsion by using a billion arms?
Wisdom's paper ends with a numerical result concerning a deformable 1 metre object at or near Earth's surface. Each stroke buys you ~10-23 m displacement. In order to amplify the effect, two obvious strategies come up: repetition in space and repetition in time. Mechanical concerns restrict the update frequency - there's a big question mark against applying THz to an object of that size, no matter how light, I think (someone might prove me wrong using extended nanoscale structures though). How spatial amplification might work is not clear to me. Certainly "a billion arms" doesn't do it for me.
The thing is, it is not unique. I can predict the same thing using GR, resulting from variation of the metric coefficient. So it wouldn't solve anything. Again, PV is simply an alternative interpretation of GR. The math is identical, so the predictions are also identical. Until we have a verifiable "accepted" model of Quantum Gravity, both PV and GR are classical theories which are complimentary interpretations of the observable data. My QG model, is an engineering tool that works within the parameters I need it to work. That's all.
Todd
Prof. Wisdom proved that an astronaut can swim in space just by using his arms (albeit with an extremely small stroke) using General Relativity. Can the Puthoff PV theory show the same result ? (that an astronaut can swim in space just by using his arms)
Someone will also have to design a very small machine to test General Relativity by swimming.
If it works I wonder if it can be turned into a practical method of space propulsion by using a billion arms?
Yes, but I did ask for something experimentally verifiable. If everything, including our measuring sticks, is changing then how could we know? Can you devise any experiment to test any of PV's unique predictions?Can PV make any experimentally verifiable predictions different to those made by mainstream physics, that would earn it a place at the table? I think not, otherwise it would be big news....
Now I agree with you that the Puthof's Polarizable Vacuum theory cannot be a replacement for General Relativity and its endorsement of Mach (not March ! ;)) intuition on the origin of inertia. It was also; I would say; the view of Puthof himself who clearly wrote in 1999 that the Polarizable Vacuum theory was not yet in a positon to explain both gravitational radiation and frame-dragging effects (base of Mach ideas on inertia incorporation in General Relativity).
The work of Puthoff, Joe Depp, Riccardo Storti and myself, have resolved these issues with PV by 2005. The PV warp drive is frame dragging in PV just as it is in GR. It turns out that the metric coefficients of GR are "equivalent" to a variable refractive index tensor, composed of QV interactions with matter.
What I have come to understand clearly, is that the differences between PV and GR are simply a matter of how one interprets the math. Space-time curvature of empty vacuum VS interactions of matter with the QV. I have developed a Quantum model for PV that works well enough for engineering purposes. If even 1 millionth of the work done in the name of GR were done for PV, all this would be obvious and text book trivia, but history has lead thousands of people to work on GR. Where, only a handful of mostly engineers have even grasped the power of PV as a foundation for understanding GR. More people should study it, as it really does lead to new ideas that fit within the GR framework, simply by re-interpreting the physical interaction of matter & metric.
FYI: I am still waiting for JBIS to give me any review or comments on my Electromagnetic Quantum Vacuum Warp Drive paper that I submitted last January. Which shows how the QV model of PV is used to re-interpret GR and better understand what is needed to go FTL. You can find related work on my RG page.
Todd
Hypothetically, it predicts that the Hubble expansion "red shift" could be (partly) due to our rulers contracting as the universe runs out of energy. All it takes is for 1 meter to contract by 6.8 nanometers/century, as the driving power of the ZPF runs down in the present, relative to the distant past we view through our telescope, to account for the Hubble expansion.
Todd
The thing is, it is not unique. I can predict the same thing using GR, resulting from variation of the metric coefficient. So it wouldn't solve anything. Again, PV is simply an alternative interpretation of GR. The math is identical, so the predictions are also identical. Until we have a verifiable "accepted" model of Quantum Gravity, both PV and GR are classical theories which are complimentary interpretations of the observable data. My QG model, is an engineering tool that works within the parameters I need it to work. That's all.
Todd
Prof. Wisdom proved that an astronaut can swim in space just by using his arms (albeit with an extremely small stroke) using General Relativity. Can the Puthoff PV theory show the same result ? (that an astronaut can swim in space just by using his arms)
Teach someone who knows how to do Differential Geometry how to do PV and we'll find out. I saw a Schwarszchild metric in Prof. Wisdom's paper. Since this metric is identical in PV, I suspect the results are identical too. Unfortunately, Diff. Geometry is at the limit of my mathematical abilities. So I'm not even going to try and prove it to anyone. I encourage others with more formidable math skills than I, to give it a shot.
Todd
About arcing in cavities
https://en.wikipedia.org/wiki/Kilpatrick_limit
Yes, but I did ask for something experimentally verifiable. If everything, including our measuring sticks, is changing then how could we know? Can you devise any experiment to test any of PV's unique predictions?Can PV make any experimentally verifiable predictions different to those made by mainstream physics, that would earn it a place at the table? I think not, otherwise it would be big news....
Now I agree with you that the Puthof's Polarizable Vacuum theory cannot be a replacement for General Relativity and its endorsement of Mach (not March ! ;)) intuition on the origin of inertia. It was also; I would say; the view of Puthof himself who clearly wrote in 1999 that the Polarizable Vacuum theory was not yet in a positon to explain both gravitational radiation and frame-dragging effects (base of Mach ideas on inertia incorporation in General Relativity).
The work of Puthoff, Joe Depp, Riccardo Storti and myself, have resolved these issues with PV by 2005. The PV warp drive is frame dragging in PV just as it is in GR. It turns out that the metric coefficients of GR are "equivalent" to a variable refractive index tensor, composed of QV interactions with matter.
What I have come to understand clearly, is that the differences between PV and GR are simply a matter of how one interprets the math. Space-time curvature of empty vacuum VS interactions of matter with the QV. I have developed a Quantum model for PV that works well enough for engineering purposes. If even 1 millionth of the work done in the name of GR were done for PV, all this would be obvious and text book trivia, but history has lead thousands of people to work on GR. Where, only a handful of mostly engineers have even grasped the power of PV as a foundation for understanding GR. More people should study it, as it really does lead to new ideas that fit within the GR framework, simply by re-interpreting the physical interaction of matter & metric.
FYI: I am still waiting for JBIS to give me any review or comments on my Electromagnetic Quantum Vacuum Warp Drive paper that I submitted last January. Which shows how the QV model of PV is used to re-interpret GR and better understand what is needed to go FTL. You can find related work on my RG page.
Todd
Hypothetically, it predicts that the Hubble expansion "red shift" could be (partly) due to our rulers contracting as the universe runs out of energy. All it takes is for 1 meter to contract by 6.8 nanometers/century, as the driving power of the ZPF runs down in the present, relative to the distant past we view through our telescope, to account for the Hubble expansion.
Todd
The thing is, it is not unique. I can predict the same thing using GR, resulting from variation of the metric coefficient. So it wouldn't solve anything. Again, PV is simply an alternative interpretation of GR. The math is identical, so the predictions are also identical. Until we have a verifiable "accepted" model of Quantum Gravity, both PV and GR are classical theories which are complimentary interpretations of the observable data. My QG model, is an engineering tool that works within the parameters I need it to work. That's all.
Todd
Prof. Wisdom proved that an astronaut can swim in space just by using his arms (albeit with an extremely small stroke) using General Relativity. Can the Puthoff PV theory show the same result ? (that an astronaut can swim in space just by using his arms)
Teach someone who knows how to do Differential Geometry how to do PV and we'll find out. I saw a Schwarszchild metric in Prof. Wisdom's paper. Since this metric is identical in PV, I suspect the results are identical too. Unfortunately, Diff. Geometry is at the limit of my mathematical abilities. So I'm not even going to try and prove it to anyone. I encourage others with more formidable math skills than I, to give it a shot.
Todd
Please find attached a Venn diagram that Prof. Dr. Jim Woodward sent out over the past weekend that summarizes these issues: Mainstream Physics (Quantum Mechanics and General Relatiivity), then PV and Mach Effect, etc.
So you have an asymmetrical current flow abd a frustum that wants to move up and rotate to the right. If you flipped it would it rotate to the left?
NSF-1701 update - So long galinstan hello 10' feed of filament, ground and HV wires. Laser displacement sensor mounted on tripod, goodbye laser pointer. Controller and display ordered today for lds. Couple of vertical aluminum bars added to Doc's oil dampener to retard horizontal oscillations...works great. Powered up fine with long feed wires. Droops and loops seem to flex easily. Miller time...Really looking good rfmwguy. You should be very excited to crank this tar baby up.
Yes I am. Focus has been on improving test stand and resolution. I will characterize thermal lift, then move towards frustum tuning. Might even try to match frustum to the +/- 40 mhz bandwidth the maggy has rather than a single freq resonance. This normally involves 2 cavities loosely coupled, zeros at beginning and end of bandwidth. A single cavity will be a challenge. Not yet sure how to get 2 resonance zero poles out of a single cavity...NSF-1701 update - So long galinstan hello 10' feed of filament, ground and HV wires. Laser displacement sensor mounted on tripod, goodbye laser pointer. Controller and display ordered today for lds. Couple of vertical aluminum bars added to Doc's oil dampener to retard horizontal oscillations...works great. Powered up fine with long feed wires. Droops and loops seem to flex easily. Miller time...Really looking good rfmwguy. You should be very excited to crank this tar baby up.
Shell
I have made runs with the loop antenna. csv data and png view files for 3 runs are here.BigEng run Dr. Rodel's 2.47GHz Ex,Ey,Ez in a gif loop.
https://drive.google.com/folderview?id=0B1XizxEfB23tcEVRLTlXR2JxZXM&usp=sharing (https://drive.google.com/folderview?id=0B1XizxEfB23tcEVRLTlXR2JxZXM&usp=sharing)
Thirty two cycle runs with the final 14 one-tenth cycle time slices presented.
These runs are using SeeShells' Crazy-Eddie 2 (CE2) frustum model and Rodal's 0.054 meter diameter loop antenna. Two of the runs place the loop at 0.054 meters from the small end of the frustum, while the other run has the loop placed 0.054 meters from the big end.
Finding resonance for this frustum/antenna combination was a chore. Using resolution = 100 (which has always worked well in the past), Harminv invariably calculated resonant frequency at 2.500 GHz and Q - O(300-500). I ran and uploaded one set of data with this frequency - I was loosing hope. Fortunately I decided to check convergence and was able to complete Harminv runs with resolution = 200. I was amazed.
Doubling resolution, using resolution = 200, Harminv calculated resonant frequency = 2.47065 GHz, differing by only 10's of Hz for the big end or small end antenna location. And the stupid low Q values went away. With the loop antenna toward the big end of the frustum, calculated Q ~= 6 million, and with the antenna toward the small end, calculated Q ~= 28 million. While these values are not representative of a real world metal construction, they do indicate that the cavity will resonate strongly at the drive frequency of 2.47065 GHz. I uploaded data sets for these two cases at the link above.
Any readers with antenna knowledge, please evaluate the png views with an eye toward fidelity of the model field patterns compared to real antenna field patterns. I know that the frustum complicates this evaluation but thanks.
We are looking at a plane perpendicular to the z axis as the fields pass through. It looks like the fields rotate but I speculate it is more like a cork-screw pattern.
I wonder what the x or y views look like.
Orbital angular momentum comes to mind.
Anyone have any suggestions, comments, questions?
-Kurt
This requires some care because, as is well known, spacetime has a right-hand thread.:) Really?, in which direction is spacetime's right-handed screw oriented? Towards a black-hole?
All wave guide experts out there, what can you tell me about the shape of the EM fields in a wave guide excited by a noisy magnetron. How long should the wave guide be, its height and width? But mostly, what do the EM field patterns look like?Here is a primer.
Anyone have any suggestions, comments, questions?
-Kurt
What are the dimensions of the frustum and the waveguide in your video?
One thing that keeps surprising me is how big the waveguides are WRT their attached frustum (same problem with Tajmar's experiment, where this issue is even greater); while Shawyer's waveguide always seems very narrow.
Is there a reason why large standard waveguides are used (remember they can account for a large frequency range) instead of specific smaller waveguides matched with the source frequency?
Hasn't Shawyer had some resonators that operated at higher frequency?
Hasn't Shawyer had some resonators that operated at higher frequency?
Yes, the latest known as the "Flight Thruster" designed for Boeing. It was powered by 3.85 GHz travelling-wave tube amplifiers (TWTAs). But former ones used standard 2.45 GHz magnetrons.
However my recollection may be affected by Shawyer's drawings showing very narrow waveguides, while actual pictures of his thrusters show bigger waveguides (and sometimes, coax inputs).
What was your RF source? A magnetron, powered by what?Anyone have any suggestions, comments, questions?
-Kurt
What are the dimensions of the frustum and the waveguide in your video?
One thing that keeps surprising me is how big the waveguides are WRT their attached frustum (same problem with Tajmar's experiment, where this issue is even greater); while Shawyer's waveguide always seems very narrow.
Is there a reason why large standard waveguides are used (remember they can account for a large frequency range) instead of specific smaller waveguides matched with the source frequency?
The frustum is designed to resonate with a TE 011 mode and has r_top = 1.3 r_bottom = 4.3 and h =8 inches. The waveguide is a standard WR340 because we plan to buy the waveguide to coax adapter from a manufacturer.
I would rather make the after-aperture waveguide smaller so that more energy is contained in the frustum, but I'll need to play with the simulation more to find the right dimensions.
Hasn't Shawyer had some resonators that operated at higher frequency?
It was pretty clear that the mode shape would looks asymmetric and that it would rotate around the central axis.We are looking at a plane perpendicular to the z axis as the fields pass through. It looks like the fields rotate but I speculate it is more like a cork-screw pattern.
I wonder what the x or y views look like.
Orbital angular momentum comes to mind.
We are looking at a plane perpendicular to the z axis as the fields pass through. It looks like the fields rotate but I speculate it is more like a cork-screw pattern.
I wonder what the x or y views look like.
Orbital angular momentum comes to mind.
https://drive.google.com/folderview?id=0B1XizxEfB23tSUtybjhCN1ZlMzQ&usp=sharing&tid=0B1XizxEfB23tcEVRLTlXR2JxZXMWe are looking at a plane perpendicular to the z axis as the fields pass through. It looks like the fields rotate but I speculate it is more like a cork-screw pattern.
I wonder what the x or y views look like.
Orbital angular momentum comes to mind.
I though Rodal wanted the antenna near the large base. Gif seems to show antenna near the small base. Maybe animations of both setups would be useful?
It was pretty clear that the mode shape would looks asymmetric and that it would rotate around the central axis.We are looking at a plane perpendicular to the z axis as the fields pass through. It looks like the fields rotate but I speculate it is more like a cork-screw pattern.
I wonder what the x or y views look like.
Orbital angular momentum comes to mind.
This pattern is a result of the long loop antenna with several half wavelength (different signs/ vector of the field along the loop wire)... That was what i am talking about during the discussion about.
http://forum.nasaspaceflight.com/index.php?topic=38203.msg1416734#msg1416734
http://forum.nasaspaceflight.com/index.php?topic=38203.msg1423000#msg1423000
http://forum.nasaspaceflight.com/index.php?topic=38203.msg1418157#msg1418157
... ::)
Compare the field pattern with the pure loop antenna gif
Nevertheless it looks nice aero, great work! High Q looks good :)
1) Sounds good i hope you are right with that.It was pretty clear that the mode shape would looks asymmetric and that it would rotate around the central axis.We are looking at a plane perpendicular to the z axis as the fields pass through. It looks like the fields rotate but I speculate it is more like a cork-screw pattern.
I wonder what the x or y views look like.
Orbital angular momentum comes to mind.
This pattern is a result of the long loop antenna with several half wavelength (different signs/ vector of the field along the loop wire)... That was what i am talking about during the discussion about.
http://forum.nasaspaceflight.com/index.php?topic=38203.msg1416734#msg1416734
http://forum.nasaspaceflight.com/index.php?topic=38203.msg1423000#msg1423000
http://forum.nasaspaceflight.com/index.php?topic=38203.msg1418157#msg1418157
... ::)
Compare the field pattern with the pure loop antenna gif
Nevertheless it looks nice aero, great work! High Q looks good :)
Four points deserve to be made, and not ignored:
1) Previous runs showed that the amount of time of these two runs is NOT long enough to get anywhere close to a steady, well-formed mode. Examination of the csv files shows that it takes 64 to 128 cycles to get close to well-formed modes, for more symmetric geometries (Yang/Shell at 6 degrees). Therefore present observations based on this early state may be premature. Longer runs to 128 cycles would be required to know the non-transient shape of the modes.
2) The runs for the Yang/Shell geometry have to be taken under consideration that the cone half-angle in that case is much smaller, only 6 degrees, hence the Yang/Shell geometry is much more like a cylinder than a truncated cone. This geometry has a much higher cone angle.
3) I don't recall that the small loop run resulted in any better defined cylindrical mode. One thing we have learnt from Meep is that it is not trivial to impose well-formed cylindrical modes, particularly of the TE type on a conical frustum
4) The png images shown for these last two runs have gone back to the multiple contour lines with recurrent colors, which do NOT allow one to ascertain the magnitude of the fields. Furthermore, no color/numerical bar is shown to ascertain the magnitude of the fields. Are you therefore making an assessment without knowing the magnitude of the fields ?
::)
Anyone have any suggestions, comments, questions?
-Kurt
What are the dimensions of the frustum and the waveguide in your video?
One thing that keeps surprising me is how big the waveguides are WRT their attached frustum (same problem with Tajmar's experiment, where this issue is even greater); while Shawyer's waveguide always seems very narrow.
Is there a reason why large standard waveguides are used (remember they can account for a large frequency range) instead of specific smaller waveguides matched with the source frequency?
The frustum is designed to resonate with a TE 011 mode and has r_top = 1.3 r_bottom = 4.3 and h =8 inches. The waveguide is a standard WR340 because we plan to buy the waveguide to coax adapter from a manufacturer.
I would rather make the after-aperture waveguide smaller so that more energy is contained in the frustum, but I'll need to play with the simulation more to find the right dimensions.
Hasn't Shawyer had some resonators that operated at higher frequency?
What was your RF source? A magnetron, powered by what?
Shell
1) Sounds good i hope you are right with that.It was pretty clear that the mode shape would looks asymmetric and that it would rotate around the central axis.We are looking at a plane perpendicular to the z axis as the fields pass through. It looks like the fields rotate but I speculate it is more like a cork-screw pattern.
I wonder what the x or y views look like.
Orbital angular momentum comes to mind.
This pattern is a result of the long loop antenna with several half wavelength (different signs/ vector of the field along the loop wire)... That was what i am talking about during the discussion about.
http://forum.nasaspaceflight.com/index.php?topic=38203.msg1416734#msg1416734
http://forum.nasaspaceflight.com/index.php?topic=38203.msg1423000#msg1423000
http://forum.nasaspaceflight.com/index.php?topic=38203.msg1418157#msg1418157
... ::)
Compare the field pattern with the pure loop antenna gif
Nevertheless it looks nice aero, great work! High Q looks good :)
Four points deserve to be made, and not ignored:
1) Previous runs showed that the amount of time of these two runs is NOT long enough to get anywhere close to a steady, well-formed mode. Examination of the csv files shows that it takes 64 to 128 cycles to get close to well-formed modes, for more symmetric geometries (Yang/Shell at 6 degrees). Therefore present observations based on this early state may be premature. Longer runs to 128 cycles would be required to know the non-transient shape of the modes.
2) The runs for the Yang/Shell geometry have to be taken under consideration that the cone half-angle in that case is much smaller, only 6 degrees, hence the Yang/Shell geometry is much more like a cylinder than a truncated cone. This geometry has a much higher cone angle.
3) I don't recall that the small loop run resulted in any better defined cylindrical mode. One thing we have learnt from Meep is that it is not trivial to impose well-formed cylindrical modes, particularly of the TE type on a conical frustum
4) The png images shown for these last two runs have gone back to the multiple contour lines with recurrent colors, which do NOT allow one to ascertain the magnitude of the fields. Furthermore, no color/numerical bar is shown to ascertain the magnitude of the fields. Are you therefore making an assessment without knowing the magnitude of the fields ?
::)
2) Yes. May be an averaging looks like the searched pattern?
3) Yes the little loop leads to worse coupling and tiny Q :/
What do you think about the following design with short loops?
Anyone have any suggestions, comments, questions?
-Kurt
What are the dimensions of the frustum and the waveguide in your video?
One thing that keeps surprising me is how big the waveguides are WRT their attached frustum (same problem with Tajmar's experiment, where this issue is even greater); while Shawyer's waveguide always seems very narrow.
Is there a reason why large standard waveguides are used (remember they can account for a large frequency range) instead of specific smaller waveguides matched with the source frequency?
The frustum is designed to resonate with a TE 011 mode and has r_top = 1.3 r_bottom = 4.3 and h =8 inches. The waveguide is a standard WR340 because we plan to buy the waveguide to coax adapter from a manufacturer.
I would rather make the after-aperture waveguide smaller so that more energy is contained in the frustum, but I'll need to play with the simulation more to find the right dimensions.
Hasn't Shawyer had some resonators that operated at higher frequency?
What was your RF source? A magnetron, powered by what?
Shell
The simulation power source is a plane wave in a coax, which is how the EM Pro demo does a coax to waveguide adapter. This plane wave has an impedance line drawn across it from the inside of the outer conductor to the outside of the inner conductor. It is also defined as a 1 W modal power feed as opposed to a 50 Ohm voltage source, which are the only two FEM excitations available (also something I have seen in demo videos online).
A number of experimental papers claim to have excited TE012 or TE013 modes in an EM Drive conical frustum. They do so based on calculations based on simplifications (standing wave eigenvalue analysis instead of transient analysis of travelling waves), but never based on measurement.You're quite right Dr. Rodel. TE modes have been notorious to excite in a frustum and many have tried and died.
It is to be noted that only one (1) organization (NASA) has actually verified, with an experimental measurement, the actual mode that was excited, and it was a transverse magnetic mode: TM212.
Talk is cheap. Anybody can claim that they excited a TE mode in an EM Drive frustum. It is noteworthy that nobody has experimentally verified it. Until further verification a skeptical reader of these reports might as well think that a TM mode was excited instead..
Anyone have any suggestions, comments, questions?
-Kurt
What are the dimensions of the frustum and the waveguide in your video?
One thing that keeps surprising me is how big the waveguides are WRT their attached frustum (same problem with Tajmar's experiment, where this issue is even greater); while Shawyer's waveguide always seems very narrow.
Is there a reason why large standard waveguides are used (remember they can account for a large frequency range) instead of specific smaller waveguides matched with the source frequency?
The frustum is designed to resonate with a TE 011 mode and has r_top = 1.3 r_bottom = 4.3 and h =8 inches. The waveguide is a standard WR340 because we plan to buy the waveguide to coax adapter from a manufacturer.
I would rather make the after-aperture waveguide smaller so that more energy is contained in the frustum, but I'll need to play with the simulation more to find the right dimensions.
Hasn't Shawyer had some resonators that operated at higher frequency?
What was your RF source? A magnetron, powered by what?
Shell
The simulation power source is a plane wave in a coax, which is how the EM Pro demo does a coax to waveguide adapter. This plane wave has an impedance line drawn across it from the inside of the outer conductor to the outside of the inner conductor. It is also defined as a 1 W modal power feed as opposed to a 50 Ohm voltage source, which are the only two FEM excitations available (also something I have seen in demo videos online).
Well that limits you to modeling a lot of tings that could happen vs a real world. At least with meep we can do a little fudging around.
Do you have a choice of where to put your feed? End or sidewall and are you limited to a snub with just drawing a impedance line. Can you call out the bandwidth of the incoming RF? Can you change phasing of the incoming signal? Could you model a dual waveguide feed 180 degrees apart on the side walls (a mirror if you like) and change the phasing of the second input to match? This should give you a very clean TE011 mode generation.
Thoughts.
Shell
...I don't quite get the differentiation you are describing between FDTD and FEM.
I know that for the FDTD simulations I can use a 50 ohm voltage source and define a waveform, however I haven't quite figured out how to do those sims well yet. For the simulations I've been running (FEM) the placement of the feed is easy to change and I could put as many excitations as necessary so long as they are on the mesh boundary. The last idea would be very interesting to see, but I don't know how easy it would be to actually create and power that system.
Luckily if we are designing it for an amplifier we don't need to worry about frequency distribution, definitely not easy to model the magnetron...
I need to keep working at it to get the FDTD sims to work well, but I still have yet to master the FEM.
1...
2...
I don't quite get the differentiation you are describing between FDTD and FEM.
Meep uses the central difference method both in the space and time domains to solve transient problems. One can use the Finite Element method in space with Finite Difference in the time domain (FDTD) to solve transient problems. I wrote several such programs many years ago to solve very nonlinear problems. Actually most Finite Element programs use Finite Difference methods in the time domain to solve transient problems.
Perhaps when you are referring to the Finite Element method you are referring to an eigenvalue solution using the Finite Element method ? Is your FDTD solution using finite difference or finite elements in the space domain?
Um can somebody explain to me why TE012 is so special? I mean this thing is looking more and more propeller like as we go on. For god stakes it even seems to be torquing the frustum similar to what a propeller does. What fluid is it acting on? I don't have the fogiest. The swimming in space article gives me some interesting ideas, but anything dealing with physics at that level tends to come down to math, not intuition.
Ok, so basically you're trying to circularly polarize the wave and TE is better for this purpose than TM. So why is one TE mode any better than any other? Are you trying to circularly polarize an evanescent wave and TE012 is somehow special? If so why the frustum? Are we somehow generating more evanescent waves by using it? More evanescent waves in one direction than another (greater area of the big base than the small base to generate them, would explain why the symmetrical test was a null)? If so why on earth would an evenescent wave do something that a normal one could not? If evenescent waves tend to be generated 1/3 wavelength from an antenna what effect does the frustum deforming the wave have? Why Q? Does the probability of generating an evenescent wave increase with each bounce? Does the effect just require a highly energetic environment?
Does this paper have any bearing on the matter at hand? (Singular evanescent wave resonances) http://arxiv.org/abs/1311.3718 (http://arxiv.org/abs/1311.3718)
This thing seems to spin up (turn on delay), spin down (turn off delay) and torques to one side. It acts like a propeller and I'm completely at a loss as to how it could be doing anything in a vacuum chambers. My only thought is that the torquing (reported here and with Tajmar) is somehow the result of the use of a waveguide making the thing look more propeller like than it actually is.
Think I'm going to read a book and not think about EMDrives for a bit.
...
I am wondering if my post on this thread is too convoluted and no one feels they understand it, or if people feel they understand it but think that I don't know what I am talking about. It does appear everyone is very busy already and so maybe I should be posting this in a separate thread? I feel like it qualifies as a type of EM drive so maybe it should be here and just sit a bit on the back shelf? Any suggestions?
One question I have is if anyone has measured with a Hall effect magnetic field meter (http://hyperphysics.phy-astr.gsu.edu/hbase/magnetic/hall.html), an osculating signal that decreases with 1/r^3 coming from outside the base of a resonating cavity which changes in phase with distance. I do expect such a signal to be there in the frame of the meters moving charge. I am not sure a meter exists that could record data fast enough though it is possible with the right design, I think. It would at least appear as noise on a meter that was too slow.
Are there any arguments for why it won't work?
Are there any questions?
Suggestions, that I should move it to a new thread?
I don't quite get the differentiation you are describing between FDTD and FEM.
Meep uses the central difference method both in the space and time domains to solve transient problems. One can use the Finite Element method in space with Finite Difference in the time domain (FDTD) to solve transient problems. I wrote several such programs many years ago to solve very nonlinear problems. Actually most Finite Element programs use Finite Difference methods in the time domain to solve transient problems.
Perhaps when you are referring to the Finite Element method you are referring to an eigenvalue solution using the Finite Element method ? Is your FDTD solution using finite difference or finite elements in the space domain?
Yes, the FEM solver in EMPro is an Eigenvalue method, however it is different than the pure Eigenfrequency solver (another option) which does not have a source but simply finds the resonant frequency of whatever geometry you give it.
I'm not sure the distinction between finite elements and finite difference, (both of them divide the space into small cubes where electric/magnetic fields are calculated right? )
This quote from the Keysight manual will probably clarify:
"In the FDTD approach, both space and time are divided into discrete segments. Space is
segmented into box-shaped cells, which are small compared to the wavelength. The electric fields are located on the edges of the box and the magnetic fields are positioned on the faces as shown in the figure below. This orientation of the fields is known as the Yee cell, and is the basis for FDTD."
source: http://edadownload.software.keysight.com/eedl/empro/2010/pdf/emprosim.pdf
......
It seems like it would be possible, as you said, with fast enough data collection and a sensitive enough probe.
What would be the result of such a measurement?
2...
Um can somebody explain to me why TE012 is so special? I mean this thing is looking more and more propeller like as we go on. For god stakes it even seems to be torquing the frustum similar to what a propeller does. What fluid is it acting on? I don't have the fogiest. The swimming in space article gives me some interesting ideas, but anything dealing with physics at that level tends to come down to math, not intuition.
Ok, so basically you're trying to circularly polarize the wave and TE is better for this purpose than TM. So why is one TE mode any better than any other? Are you trying to circularly polarize an evanescent wave and TE012 is somehow special? If so why the frustum? Are we somehow generating more evanescent waves by using it? More evanescent waves in one direction than another (greater area of the big base than the small base to generate them, would explain why the symmetrical test was a null)? If so why on earth would an evenescent wave do something that a normal one could not? If evenescent waves tend to be generated 1/3 wavelength from an antenna what effect does the frustum deforming the wave have? Why Q? Does the probability of generating an evenescent wave increase with each bounce? Does the effect just require a highly energetic environment?
Does this paper have any bearing on the matter at hand? (Singular evanescent wave resonances) http://arxiv.org/abs/1311.3718 (http://arxiv.org/abs/1311.3718)
This thing seems to spin up (turn on delay), spin down (turn off delay) and torques to one side. It acts like a propeller and I'm completely at a loss as to how it could be doing anything in a vacuum chambers. My only thought is that the torquing (reported here and with Tajmar) is somehow the result of the use of a waveguide making the thing look more propeller like than it actually is.
Think I'm going to read a book and not think about EMDrives for a bit.
I believe the more fundamental the mode, the the higher amplitude of resonance. Whether TE or TM will 'thrust' better is still up in the air IMO. But we do know Yang claims the TE011 mode to be the best she could simulate, and she reported the largest thrust values.
"It was found that the thruster cavity made by copper and resonating on the equivalent TE011 mode has a quality factor 320400 and generates total net EM thrust 411 mN for 1000 W 2.45 GHz incident microwave"
-Yang 2013
EW's TM212 seemed to work, but thrust to power was significantly less. And we can't forget they needed a dielectric, a mystery that still hasn't been solved. I don't know if I'd settle with Paul March's original theory that the phase modulation and amplitude modulation of the magnetron contributes to no need for a dielectric. I think it has to do with what mode was excited in EW's cavity and the need for significant field asymmetry. Perhaps the frustum shape alone can cause enough asymmetry when using fundamental modes because they span more of the tapered height. A TM 212 on the other hand does not span very much of the height so a dielectric may have been necessary to 'squish' the fields down on one side so that enough asymmetry was created for thrust.
But take all of that with a grain of salt, I haven't spent as much time thinking about why this thing works and rather focused on how to get one to work.
The TE modes are highly desirable for tunable high-Q resonators because they do not require current crossing between the outer Wall and the circular end plates of the cavity, and because the Q factor is high. These particular modes have therefore found Wide application.
Hey Doc, with all the recent talk about corkscrew modeling, aren't you glad I didn't wander off into an EM Vortex type analogy?There is nothing wrong in a helical wave injected into the frustum if done right. It also has nothing to do with superluminal wave velocities.
I'm very pleased with myself, holding back on my early, wild speculations about mass displacement from the center of the vortices to avoid superluminal velocities...doooh! Sorry, Doc ;)
Can anyone here convert a .skp to a GDSII?You could try to convert (http://www.file-extensions.org/convert-skp-to-dxf)to .dxf first and then (http://en.freedownloadmanager.org/tutorials/how-to-convert-dxf-to-gdsii-with-layouteditor-2014.html)to GDSII.
I'm using the free version of sketchup which only exports in a .skp and I need a GDS to import into a EM model.Can anyone here convert a .skp to a GDSII?You could try to convert (http://www.file-extensions.org/convert-skp-to-dxf)to .dxf first and then (http://en.freedownloadmanager.org/tutorials/how-to-convert-dxf-to-gdsii-with-layouteditor-2014.html)to GDSII.
Why the field on the loop antena appears like a traveling wave along the loop? The current is not balanced?
When a loop is feeded by a transmission line there are two antisymmetric current waves, and one will see the fields on the loop arising as two couterpropagating waves and resulting a stationary wave on the loop.
What is going on?
Why the field on the loop antena appears like a traveling wave along the loop? The current is not balanced?
When a loop is feeded by a transmission line there are two antisymmetric current waves, and one will see the fields on the loop arising as two couterpropagating waves and resulting a stationary wave on the loop.
What is going on?
I programmed it like the receiving loop antenna on my TV set. Is that not right?
At low frequencies it is not important at all. But if the loop is in the dimension of the wavelength the situation is clear different. For example, if you look to smith diagram, between 0.5 and ~0.95 wavelengths the loop acts capacitive.
Why the field on the loop antena appears like a traveling wave along the loop? The current is not balanced?
When a loop is feeded by a transmission line there are two antisymmetric current waves, and one will see the fields on the loop arising as two couterpropagating waves and resulting a stationary wave on the loop.
What is going on?
Has anyone done a mathematical proof to make sure a stable TE012 is possible in a frustum at these frequencies? We would all feel a bit silly if we spent all this time and effort trying to do something that was impossible. (Certain ironies with the above statement and this entire project are noted).
Speaking of which, here is the dispersion measure plot from the Arecibo, Fast Radio Burst detection. I've said elsewhere that I think its either the result of the classified project Shawyer says he was working on (very likely) or possibly somebody else using an EMDrive subject to engineering restraints we are not currently aware of (highly unlikely going to extremely unlikely if that somebody is not associated with the planet Earth). Since I don't know the cutoff for Arecibo's equipment this is of limited value (if a full run starts at 1hz and goes all the way up to the high gammas it clearly stellar in nature). Still, I can't help but feel that if I could, arbitrarily, pick a frequency to start poking about around with an EMDrive, somewhere in this range might bear interesting fruit. (Paper: http://arxiv.org/abs/1404.2934 (http://arxiv.org/abs/1404.2934))
At low frequencies it is not important at all. But if the loop is in the dimension of the wavelength the situation is clear different. For example, if you look to smith diagram, between 0.5 and ~0.95 wavelengths the loop acts capacitive.
Why the field on the loop antena appears like a traveling wave along the loop? The current is not balanced?
When a loop is feeded by a transmission line there are two antisymmetric current waves, and one will see the fields on the loop arising as two couterpropagating waves and resulting a stationary wave on the loop.
What is going on?
A standing wave at the antenna loop is only true if the antenna itself is also in resonance (exact multiple of half wavelength).
And yes in real world one have reflections at every discontinuity...
If this is not a answer to your question, please formulate a clear question. English isn't my natural language..
http://personal.ee.surrey.ac.uk/Personal/D.Jefferies/loop.html (@Shell, thanks for this link :) )
http://www.antennenkoppler.de/achim/antenna/Impedanz_im_Smith_1.html
I don't know what I'm doing but here is my "Magnetron/waveguide" feed.http://www.rfcafe.com/references/electrical/waveguide.htm
https://drive.google.com/folderview?id=0B1XizxEfB23tUWZVY2RMc3lJbVU&usp=sharing (https://drive.google.com/folderview?id=0B1XizxEfB23tUWZVY2RMc3lJbVU&usp=sharing)
I've coded a constant frequency for use as a wave length ruler, and am exciting the cavity at a variable frequency parameter, both are set to 2.47 GHz, and the constant won't change.
The dimensions are x= wl/4, z = wl/2 and the length, y = 2*wl. (constants) The x and z dimensions are then increased by 30% as I read somewhere that they should be. I hope to be able to shorten the y dimension as that length will make the meep computational lattice quite large.
The structure is excited from a rectangular plate wl/4 from the big end. The plate dimensions are yp = 0, xp = 0.9*x, zp=0.9*z (all constants) excited by the Ex component. The resulting Hz component is displayed.
I can use all the help I can get.
I don't know what I'm doing but here is my "Magnetron/waveguide" feed.http://www.rfcafe.com/references/electrical/waveguide.htm
https://drive.google.com/folderview?id=0B1XizxEfB23tUWZVY2RMc3lJbVU&usp=sharing (https://drive.google.com/folderview?id=0B1XizxEfB23tUWZVY2RMc3lJbVU&usp=sharing)
I've coded a constant frequency for use as a wave length ruler, and am exciting the cavity at a variable frequency parameter, both are set to 2.47 GHz, and the constant won't change.
The dimensions are x= wl/4, z = wl/2 and the length, y = 2*wl. (constants) The x and z dimensions are then increased by 30% as I read somewhere that they should be. I hope to be able to shorten the y dimension as that length will make the meep computational lattice quite large.
The structure is excited from a rectangular plate wl/4 from the big end. The plate dimensions are yp = 0, xp = 0.9*x, zp=0.9*z (all constants) excited by the Ex component. The resulting Hz component is displayed.
I can use all the help I can get.
Start here aero. The waveguide dims that should be used are the WR 340 or the WR430 as they are OTS waveguides falling into the 2.45 GHz range.
If you want Ill send you my pdfs of my waveguide to coax I should be getting today,
Here is the waveguide>coax that's in the mail. Maybe tomorrow.
Kurt,Here is the waveguide>coax that's in the mail. Maybe tomorrow.
Hey Shell,
What company did you order this waveguide to coax from?
We have recieved quotes for N type adapters that run $800+ and are looking for cheaper alternatives.
Thanks,
Kurt
Ok Shell, while you were doing that I went ahead and replaced my dimensions with the WR 340 dimensions, and replaced the exciter plate with a short stub in the x dimension (width - smallest dimension). That is, a stub 0.04318/2 = 0.02159 meters long. Views are here:I think for the way we have worked together we should start off with the very basic designs and wring out the issues and evolve it from there. More work but less problems with miss-communications.
https://drive.google.com/folderview?id=0B1XizxEfB23tUWZVY2RMc3lJbVU&usp=sharing (https://drive.google.com/folderview?id=0B1XizxEfB23tUWZVY2RMc3lJbVU&usp=sharing)
Is this what you have in mind, and may I ask a question?
"Do you want the meep model to reflect the hardware exactly as you plan to build it, or do you want it to reflect an idealization of what could perhaps be built along the lines of your plans?"
A very impressive lecture on RF cavities. Gets good around slide 40.
http://uspas.fnal.gov/materials/10MIT/Lecture6.pdf
and all the other ones:
https://www.google.it/search?q=resonant+cavities+site:uspas.fnal.gov&ie=utf-8&oe=utf-8&gws_rd=cr&ei=GevsVcT_K8a3a_yjv6AE
Suggestions, that I should move it to a new thread?
Suggestions, that I should move it to a new thread?
I mean no disrespect, but I would suggest moving your questions into a new thread. While the term "EM Drive" could be applied to numerous theoretical devices; I think it's fair to say that in the context of this thread, "EM Drive" is specifically referring to the design and theories presented by Shawyer. As a non-scientist viewing these discussions with a limited knowledge of physics, it's already difficult enough to keep up with the conversation here when it's focused on the frustum devices. Inserting "any device which could be described as an EM Drive" into this thread just muddies the waters even further. Again, I apologize to all of the regular posters to this thread if I'm speaking out of line, but I felt it necessary to make this suggestion.
A very impressive lecture on RF cavities. Gets good around slide 40.
http://uspas.fnal.gov/materials/10MIT/Lecture6.pdf
and all the other ones:
https://www.google.it/search?q=resonant+cavities+site:uspas.fnal.gov&ie=utf-8&oe=utf-8&gws_rd=cr&ei=GevsVcT_K8a3a_yjv6AE
I wanted to point out a problem in the MIT presentation (bold and underlined) lecture 6 on page 55 as it could cause some one frustration if trying to calculate the frequency for a cylindrical cavity. Their units for the frequency equation are not correct. They may have included an extra speed of light constant. I believe all they need is the 1/sqrt(mu*epsilon) and not c/sqrt(mu*epsilon). After this i get the right units and about the right dimensions for "a" and "d"... I think. Other than that, I found it helpful and thanks.
Here is the waveguide>coax that's in the mail. Maybe tomorrow.
Hey Shell,
What company did you order this waveguide to coax from?
We have recieved quotes for N type adapters that run $800+ and are looking for cheaper alternatives.
Thanks,
Kurt
Ok Shell, while you were doing that I went ahead and replaced my dimensions with the WR 340 dimensions, and replaced the exciter plate with a short stub in the x dimension (width - smallest dimension). That is, a stub 0.04318/2 = 0.02159 meters long. Views are here:I think for the way we have worked together we should start off with the very basic designs and wring out the issues and evolve it from there. More work but less problems with miss-communications.
https://drive.google.com/folderview?id=0B1XizxEfB23tUWZVY2RMc3lJbVU&usp=sharing (https://drive.google.com/folderview?id=0B1XizxEfB23tUWZVY2RMc3lJbVU&usp=sharing)
Is this what you have in mind, and may I ask a question?
"Do you want the meep model to reflect the hardware exactly as you plan to build it, or do you want it to reflect an idealization of what could perhaps be built along the lines of your plans?"
I think you have a great start aero with a very basic model and see if you can get the frustum cavity to resonate and do a few snapshots.
You know I want to end up with dual injectors 180 degree opposing that can wait, let's take small steps.
Shell
PS: the waveguide looks nice aero!
...
I accept that long-wavelength wave reflection may not be perturbed much by a fine mesh, so much of the function of a mesh cavity will be similar to a solid cavity. However, I do find it hard to believe that the conductivity of a sheet of copper full of holes is exactly the same as a sheet of copper without....
https://upload.wikimedia.org/wikipedia/commons/thumb/e/e9/TransmissionLineDefinitions.svg/310px-TransmissionLineDefinitions.svg.pngYes true, the first flow around the circumference looks a little bit art.
https://upload.wikimedia.org/wikipedia/commons/f/fe/Gaussian_Pulse_in_Transmission_Line.png
http://sub.allaboutcircuits.com/images/quiz/00133x01.png
See these three figures.
They shows basicaly, how a pulse travels along a transmission line.
Note the current flow on each wire of transmission line. Same amplitude, opposite signal.
Then imagine the loop antenna at the end of transmission line.
What would be the form of the currents reaching the loop antenna?
Why we are seeing only one current flux reaching the loop antenna by just one side?At low frequencies it is not important at all. But if the loop is in the dimension of the wavelength the situation is clear different. For example, if you look to smith diagram, between 0.5 and ~0.95 wavelengths the loop acts capacitive.
Why the field on the loop antena appears like a traveling wave along the loop? The current is not balanced?
When a loop is feeded by a transmission line there are two antisymmetric current waves, and one will see the fields on the loop arising as two couterpropagating waves and resulting a stationary wave on the loop.
What is going on?
A standing wave at the antenna loop is only true if the antenna itself is also in resonance (exact multiple of half wavelength).
And yes in real world one have reflections at every discontinuity...
If this is not a answer to your question, please formulate a clear question. English isn't my natural language..
http://personal.ee.surrey.ac.uk/Personal/D.Jefferies/loop.html (@Shell, thanks for this link :) )
http://www.antennenkoppler.de/achim/antenna/Impedanz_im_Smith_1.html
I liked this as it was a good place for a nice grouping of formulas.A very impressive lecture on RF cavities. Gets good around slide 40.
http://uspas.fnal.gov/materials/10MIT/Lecture6.pdf
and all the other ones:
https://www.google.it/search?q=resonant+cavities+site:uspas.fnal.gov&ie=utf-8&oe=utf-8&gws_rd=cr&ei=GevsVcT_K8a3a_yjv6AE
I wanted to point out a problem in the MIT presentation (bold and underlined)
There is nothing wrong with the "the MIT presentation (bold and underlined) lecture 6 on page 55" for the frequency for a cylindrical cavity,
Great points Herman! This was for our collage friends here with a restricted budget. Thanks for the reference!Ok Shell, while you were doing that I went ahead and replaced my dimensions with the WR 340 dimensions, and replaced the exciter plate with a short stub in the x dimension (width - smallest dimension). That is, a stub 0.04318/2 = 0.02159 meters long. Views are here:I think for the way we have worked together we should start off with the very basic designs and wring out the issues and evolve it from there. More work but less problems with miss-communications.
https://drive.google.com/folderview?id=0B1XizxEfB23tUWZVY2RMc3lJbVU&usp=sharing (https://drive.google.com/folderview?id=0B1XizxEfB23tUWZVY2RMc3lJbVU&usp=sharing)
Is this what you have in mind, and may I ask a question?
"Do you want the meep model to reflect the hardware exactly as you plan to build it, or do you want it to reflect an idealization of what could perhaps be built along the lines of your plans?"
I think you have a great start aero with a very basic model and see if you can get the frustum cavity to resonate and do a few snapshots.
You know I want to end up with dual injectors 180 degree opposing that can wait, let's take small steps.
Shell
PS: the waveguide looks nice aero!
Shell - I am sure you are aware off all this but for anyone using coax feeds:
A couple of cautions about using coax.
1) similar to real estate, with coax it is Low Loss, Low Loss, Low Loss - The Traveller had ID some good low loss coax back on Thread 3 (I think - can't find it with the wonderful search function). Expensive but very good.
2) Length is important, particularly if you are going for a dual feed. with a wavelength OTO of 12 cm, each 6cm is about a half wavelength and thus your impedance radically changes. Make sure to work your lengths out on smith chart or similar approach.
3) Loss (see item 1) for coax is normally referenced to a low SWR configuration (high RL). All well and good BUT with our noisy wide bandwidth maggies that is harder to achieve. Make sure to look at loss in off design configurations.
All I am saying here is that design of the coax feed system must be done carefully with these freqs and types of wideband sources.
Having said that - coax is generally much easier to work with than plumbing up waveguides. That is one of the driving forces behind the development of low loss Ghz coax. And good design is very do-able. There are quite a few references on the web - from very basic to quite theoretical. One of my favorites is "Reflections III Transmission Lines & Antennas" by Walter Maxwell. (W2DU - SK). Very readable and also includes quite a bit of data on smith charts.
Herman
Here is the waveguide>coax that's in the mail. Maybe tomorrow.
Hey Shell,
What company did you order this waveguide to coax from?
We have recieved quotes for N type adapters that run $800+ and are looking for cheaper alternatives.
Thanks,
Kurt
Cheap it out? Well a very low cost way to do dual waveguide injectors into the sidewalls 180 out of phase or just one would be like this...
Another way would be to mount the magnetron onto a waveguide> WR340 or 430 to antenna, then use a splitter for the Cavity Directional Coupler 800-2500MHz N 10db wide band signal 1.2/2.4/3G/4GHz from Ebay running to dual coax>waveguides 180 degrees opposing into the frustum.
You would need to make one of the coax's a Lambda/2 wavelength to provide the required 180 deg phase shift on one of the ports. VNA the cavity to fine tune the coaxial lengths and fine tune the phases. You could also drill and tap a couple holes and use trim screws in each waveguide on the frustum for finer tuning.
This setup WO the maggie and power supply would run $700-800 including coax. and adaptors.
Use a inverter power supply for the magnetron and good magnetron under $120.
I think this is something aero could model here quite quickly with your frustum dimensions just using the waveguide he created and making sure he could do the waveguides 180 degrees apart on the sidewalls of the frustum and 180 degree phase shifted.
Morning coffee thoughts...
Shell
https://upload.wikimedia.org/wikipedia/commons/thumb/e/e9/TransmissionLineDefinitions.svg/310px-TransmissionLineDefinitions.svg.pngYes true, the first flow around the circumference looks a little bit art.
https://upload.wikimedia.org/wikipedia/commons/f/fe/Gaussian_Pulse_in_Transmission_Line.png
http://sub.allaboutcircuits.com/images/quiz/00133x01.png
See these three figures.
They shows basicaly, how a pulse travels along a transmission line.
Note the current flow on each wire of transmission line. Same amplitude, opposite signal.
Then imagine the loop antenna at the end of transmission line.
What would be the form of the currents reaching the loop antenna?
Why we are seeing only one current flux reaching the loop antenna by just one side?At low frequencies it is not important at all. But if the loop is in the dimension of the wavelength the situation is clear different. For example, if you look to smith diagram, between 0.5 and ~0.95 wavelengths the loop acts capacitive.
Why the field on the loop antena appears like a traveling wave along the loop? The current is not balanced?
When a loop is feeded by a transmission line there are two antisymmetric current waves, and one will see the fields on the loop arising as two couterpropagating waves and resulting a stationary wave on the loop.
What is going on?
A standing wave at the antenna loop is only true if the antenna itself is also in resonance (exact multiple of half wavelength).
And yes in real world one have reflections at every discontinuity...
If this is not a answer to your question, please formulate a clear question. English isn't my natural language..
http://personal.ee.surrey.ac.uk/Personal/D.Jefferies/loop.html (@Shell, thanks for this link :) )
http://www.antennenkoppler.de/achim/antenna/Impedanz_im_Smith_1.html
I think it's the result of the current implementation in MEEP. aero explained what he did here
http://forum.nasaspaceflight.com/index.php?topic=38203.msg1422975#msg1422975
http://forum.nasaspaceflight.com/index.php?topic=38203.msg1422926#msg1422926
Aren't tuning screws ill-advised at high power because of arcing?
Also, how would you mitigate the reflected power back to the magnetron?
We're not trying to 'cheap it out' we're trying to stay within our budget.
Right now it seems the best option is a 200 W solid state amplifier that we could purchase for ~ 3,000. Then we buy an isolator, coax to waveguide, and create our frustum with aperture coupling.
I think symmetric power delivery may be more valuable in higher power situations and we could be better off sticking with the simpler method so we don't end up over our heads trying to make sure our two waveguides are 180 degrees out of phase.
There is nothing wrong with the "the MIT presentation (bold and underlined) lecture 6 on page 55" for the frequency for a cylindrical cavity,
...
It appears that you are either not noticing that the MIT equations have the relative permittivity and relative permeability or that you are confusing the relative values to the absolute values.
...
2) I believe the 2nd image is very important. Here Shawyer excites the frustum for only about 20% of 1 TC being (2Q)/(2 pi f) seconds. This means any phase distortion introduced in the resonant standing wave, during the short 20% of 1 TC excitation period, will stop after the excitation stops and the full non phase distorted internal EM resonant wave will be allowed to form and gen max Force. It may be that Shawyer found continual excitation only results in low Force generation due to RF feed introduced phase distortion. Another plus for solid state RF amps that can be switched on and off VERY quickly.
Has anyone done a mathematical proof to make sure a stable TE012 is possible in a frustum at these frequencies? We would all feel a bit silly if we spent all this time and effort trying to do something that was impossible. (Certain ironies with the above statement and this entire project are noted).
Speaking of which, here is the dispersion measure plot from the Arecibo, Fast Radio Burst detection. I've said elsewhere that I think its either the result of the classified project Shawyer says he was working on (very likely) or possibly somebody else using an EMDrive subject to engineering restraints we are not currently aware of (highly unlikely going to extremely unlikely if that somebody is not associated with the planet Earth). Since I don't know the cutoff for Arecibo's equipment this is of limited value (if a full run starts at 1hz and goes all the way up to the high gammas it clearly stellar in nature). Still, I can't help but feel that if I could, arbitrarily, pick a frequency to start poking about around with an EMDrive, somewhere in this range might bear interesting fruit. (Paper: http://arxiv.org/abs/1404.2934 (http://arxiv.org/abs/1404.2934))
Hi, I think I saw you talking about the FRB thing on Reddit. I honestly don't understand what you are saying. Can you ELI5 it to us please?
https://www.reddit.com/r/EmDrive/comments/3jwpdi/cribbing_somebody_elses_notes/
...Shawyer say's he discovered the EMDrive effect while working on a classified project relating to guidance of nuclear weapons. Such a guidance system might involve use of satellites in orbit. ...
2) I believe the 2nd image is very important. Here Shawyer excites the frustum for only about 20% of 1 TC being (2Q)/(2 pi f) seconds. This means any phase distortion introduced in the resonant standing wave, during the short 20% of 1 TC excitation period, will stop after the excitation stops and the full non phase distorted internal EM resonant wave will be allowed to form and gen max Force. It may be that Shawyer found continual excitation only results in low Force generation due to RF feed introduced phase distortion. Another plus for solid state RF amps that can be switched on and off VERY quickly.
Great to see you back!! :D
This is a very interesting insight into how Shawyer may now see this phenomena working. It is almost like striking a bell! Very, very interesting. Also may explain why magnetrons seem to work because of their duty cycle acting as an impromptu bell ringer. Hm.
Would that explain the long duration drop off after the power is turned off?
2) I believe the 2nd image is very important. Here Shawyer excites the frustum for only about 20% of 1 TC being (2Q)/(2 pi f) seconds. This means any phase distortion introduced in the resonant standing wave, during the short 20% of 1 TC excitation period, will stop after the excitation stops and the full non phase distorted internal EM resonant wave will be allowed to form and gen max Force. It may be that Shawyer found continual excitation only results in low Force generation due to RF feed introduced phase distortion. Another plus for solid state RF amps that can be switched on and off VERY quickly.
Great to see you back!! :D
This is a very interesting insight into how Shawyer may now see this phenomena working. It is almost like striking a bell! Very, very interesting. Also may explain why magnetrons seem to work because of their duty cycle acting as an impromptu bell ringer. Hm.
2) I believe the 2nd image is very important. Here Shawyer excites the frustum for only about 20% of 1 TC being (2Q)/(2 pi f) seconds. This means any phase distortion introduced in the resonant standing wave, during the short 20% of 1 TC excitation period, will stop after the excitation stops and the full non phase distorted internal EM resonant wave will be allowed to form and gen max Force. It may be that Shawyer found continual excitation only results in low Force generation due to RF feed introduced phase distortion. Another plus for solid state RF amps that can be switched on and off VERY quickly.
Great to see you back!! :D
This is a very interesting insight into how Shawyer may now see this phenomena working. It is almost like striking a bell! Very, very interesting. Also may explain why magnetrons seem to work because of their duty cycle acting as an impromptu bell ringer. Hm.
Would that explain the long duration drop off after the power is turned off?
No.
http://phys.org/news/2015-09-spacex-peek-crew-vehicle.html
This is one beautiful looking space vehicle.
Sorry just had to post. Spent the day getting the lasers lined up and still having issues with the red one, think I got a bad laser as I can't get it to define a nice spot even with a pinhole lens and I tried several different ones. I guess I'll need to order another, they are not the costly.
Got the scales stable attached to a set of micrometer gauges secured under the scale table (old ones I took apart) to use the screw mechanism to fine tune and set the digital scales height.
Got the Faraday cage door finished and checked out, it's radiation proof. ;)
Shell
Homer Simpson..."mmmmmm Pretty Blue Balls"http://phys.org/news/2015-09-spacex-peek-crew-vehicle.html
This is one beautiful looking space vehicle.
Sorry just had to post. Spent the day getting the lasers lined up and still having issues with the red one, think I got a bad laser as I can't get it to define a nice spot even with a pinhole lens and I tried several different ones. I guess I'll need to order another, they are not the costly.
Got the scales stable attached to a set of micrometer gauges secured under the scale table (old ones I took apart) to use the screw mechanism to fine tune and set the digital scales height.
Got the Faraday cage door finished and checked out, it's radiation proof. ;)
Shell
It's probably just stray photon molecules:
https://www.extremetech.com/extreme/213974-breakthrough-nist-study-creates-molecules-out-of-photons
http://phys.org/news/2015-09-spacex-peek-crew-vehicle.html
This is one beautiful looking space vehicle.
You got that right and with people in them too!http://phys.org/news/2015-09-spacex-peek-crew-vehicle.html
This is one beautiful looking space vehicle.
He needs to stop his rockets from blowing up before he puts those pretty capsules on top of them.
Long time lurker, first time poster here.
I have an idea way out in left field: could microwave phase conjugation using antenna arrays be implemented to create resonance at any desired input frequencies?
Some reference.
http://ieeexplore.ieee.org/xpl/login.jsp?tp=&arnumber=734509&url=http%3A%2F%2Fieeexplore.ieee.org%2Fiel4%2F22%2F15815%2F00734509.pdf%3Farnumber%3D734509
http://www.hindawi.com/journals/ijap/2010/564357/
2) I believe the 2nd image is very important. Here Shawyer excites the frustum for only about 20% of 1 TC being (2Q)/(2 pi f) seconds. This means any phase distortion introduced in the resonant standing wave, during the short 20% of 1 TC excitation period, will stop after the excitation stops and the full non phase distorted internal EM resonant wave will be allowed to form and gen max Force. It may be that Shawyer found continual excitation only results in low Force generation due to RF feed introduced phase distortion. Another plus for solid state RF amps that can be switched on and off VERY quickly.
Great to see you back!! :D
This is a very interesting insight into how Shawyer may now see this phenomena working. It is almost like striking a bell! Very, very interesting. Also may explain why magnetrons seem to work because of their duty cycle acting as an impromptu bell ringer. Hm.
Would that explain the long duration drop off after the power is turned off?
No.
Have to agree with Rodal. From a microwave perspective you are looking probably at nanoseconds (femtoseconds?) unless I am missing something. Same thing would be true as far as I know for any ionized gasses rattling around. Couldn't speak to how long a superconducting EM bell would ring on its own but it would likely still be much shorter than say a millisecond, if that.
The insight for me is that the EM Drive could possibly be best driven by a pulsed power source and not a continuous one.
That said, that long duration drop off is one of those signals that makes this such a tar patch. It shows up in different experiments, usually explained away as either thermals or stiction in the measuring apparatus.
Thing is, while thrust does not require new physics, this duration thing would if it is not just an experimental artifact...
Uh-oh...LDS display that was supposed to be working was not...bummer
I downloaded the manual and discovered the error code was a "Memory Error". It said to plug it in several times to see if it goes away. It did not. Also tried Reset and Zero signalllls without success. Good news is laser displacement sensor seems to be fine, just a problem with the display. Sent the seller a note and I'm sure they will help. Just hate delays.Uh-oh...LDS display that was supposed to be working was not...bummer
Seems more like the LCD ("Liquid Crystal Display") is working and is simply reporting an error from the device the LCD is connected to.
You many want to contact the seller and supply the picture. There could be a solution without the need to return the device.
Don
I downloaded the manual and discovered the error code was a "Memory Error". It said to plug it in several times to see if it goes away. It did not. Also tried Reset and Zero signalllls without success. Good news is laser displacement sensor seems to be fine, just a problem with the display. Sent the seller a note and I'm sure they will help. Just hate delays.Uh-oh...LDS display that was supposed to be working was not...bummer
Seems more like the LCD ("Liquid Crystal Display") is working and is simply reporting an error from the device the LCD is connected to.
You many want to contact the seller and supply the picture. There could be a solution without the need to return the device.
Don
[..]
Last night was a long sleepless night for whatever reason, mind going to fast for my age at least. Something dawned on me in the middle of the night, can you call it night dreaming instead of day dreaming and still be correct?
I'm glad everyone puts up with my mind flights of fancy, been that way most of my life. Trying to figure out the whys of something. I hope all realize I'm just using this forum as a sounding board for my half baked thoughts sometimes and what ifs or has anyone taken it into account.[..]
Last night was a long sleepless night for whatever reason, mind going to fast for my age at least. Something dawned on me in the middle of the night, can you call it night dreaming instead of day dreaming and still be correct?
I'd rather say, your mind is going too fast for other people your age.
:)
I'm glad everyone puts up with my mind flights of fancy, been that way most of my life. Trying to figure out the whys of something. I hope all realize I'm just using this forum as a sounding board for my half baked thoughts sometimes and what ifs or has anyone taken it into account.[..]
Last night was a long sleepless night for whatever reason, mind going to fast for my age at least. Something dawned on me in the middle of the night, can you call it night dreaming instead of day dreaming and still be correct?
I'd rather say, your mind is going too fast for other people your age.
:)
Got tired (way too much time spent on it) of trying to make the cheap lasers work and couldn't get a good "dot" on my graph paper even using pin hole lenses, they wanted to degrade to a fringing splat on the paper around 30 feet, maybe that is why they were so inexpensive?. So I'm going to try something a little different. http://www.ebay.com/itm/131597609908 and strap and align and focus it right on the far end of the flucrum, about 5 meters from the laser to the paper.
Shell
Added: And after all this work if the frustum proves too frustrating I'll just change my EMDrive into a thermally agitated dihydrogen monoxide machine.
I'm glad everyone puts up with my mind flights of fancy, been that way most of my life. Trying to figure out the whys of something. I hope all realize I'm just using this forum as a sounding board for my half baked thoughts sometimes and what ifs or has anyone taken it into account.[..]
Last night was a long sleepless night for whatever reason, mind going to fast for my age at least. Something dawned on me in the middle of the night, can you call it night dreaming instead of day dreaming and still be correct?
I'd rather say, your mind is going too fast for other people your age.
:)
Got tired (way too much time spent on it) of trying to make the cheap lasers work and couldn't get a good "dot" on my graph paper even using pin hole lenses, they wanted to degrade to a fringing splat on the paper around 30 feet, maybe that is why they were so inexpensive?. So I'm going to try something a little different. http://www.ebay.com/itm/131597609908 and strap and align and focus it right on the far end of the flucrum, about 5 meters from the laser to the paper.
Shell
Added: And after all this work if the frustum proves too frustrating I'll just change my EMDrive into a thermally agitated dihydrogen monoxide machine.
I have a 5mw HeNe laser I can loan you...
2) I believe the 2nd image is very important. Here Shawyer excites the frustum for only about 20% of 1 TC being (2Q)/(2 pi f) seconds. This means any phase distortion introduced in the resonant standing wave, during the short 20% of 1 TC excitation period, will stop after the excitation stops and the full non phase distorted internal EM resonant wave will be allowed to form and gen max Force. It may be that Shawyer found continual excitation only results in low Force generation due to RF feed introduced phase distortion. Another plus for solid state RF amps that can be switched on and off VERY quickly.
Great to see you back!! :D
This is a very interesting insight into how Shawyer may now see this phenomena working. It is almost like striking a bell! Very, very interesting. Also may explain why magnetrons seem to work because of their duty cycle acting as an impromptu bell ringer. Hm.
Would that explain the long duration drop off after the power is turned off?
No.
Have to agree with Rodal. From a microwave perspective you are looking probably at nanoseconds (femtoseconds?) unless I am missing something. Same thing would be true as far as I know for any ionized gasses rattling around. Couldn't speak to how long a superconducting EM bell would ring on its own but it would likely still be much shorter than say a millisecond, if that.
The insight for me is that the EM Drive could possibly be best driven by a pulsed power source and not a continuous one.
That said, that long duration drop off is one of those signals that makes this such a tar patch. It shows up in different experiments, usually explained away as either thermals or stiction in the measuring apparatus.
Thing is, while thrust does not require new physics, this duration thing would if it is not just an experimental artifact...
Resonant cavities have a TC (Time Constant) which defines the rate of energy increase or decrease. Is defined as
TC = (2 QL) / ( 2 Pi Freq).
For a SC cavity with a unloaded Q0 of 5,000,0000 and a loaded QL of 1,000,000 due to an antenna coupling factor of 0.20. QL = Q0 * antenna coupling factor, the excitation period TC is then 130us and the post excitation TC (no phase distortion from the excitation antenna's EM waves on the internal resonant wave) climbs to 650us. All at 2.45GHz.
Which would suggest the cavity can maintain the pure, non phase distorted, resonant EM waves for quite some period alter the excitation, cavity fill EM pulse is stopped.
Also suggests the antenna coupling factor is not as important as is getting an ideal impedance match to drop the frustum VSWR to as close to as 1:1 as possible.
I would again point out the use of a feed slit on the frustum side wall. To me this suggests a desire for an excitation method that will have minimal effect on the post excitation non loaded Q. Sort of how to have a RF in feed capability but not upset the frustum mechanics, smooth side wall, to obtain max non loaded Q post the excitation period.
Using the side wall slit and doing short 20% of 1 TC RF excitation pulses is a clever way to eliminate antenna coupling factor dequeuing the frustum post excitation Q and to eliminate the excitation antenna being a permanent feature inside the cavity.
At 900MHz the above 1 TC times lengthen to
Excited TC = 354us
Nonexcited TC = 1.77ms
Attached drawing shows the 20% of 1 TC excitation RF period that Shawyer mentions in his patent.
Also is attached data from his peer reviewed paper, showing the time of the pulse, and how the Force generated declines as the mainly TC driven resonant EM standing waves inside the cavity decline in strength.
Yet another report from a DIY experiment showing NO thrust from an EM Drive and instead reporting thermal effects: https://www.reddit.com/r/EmDrive/comments/3kxvjr/emdrive_build_update_5/We are getting there, Doc...slow but sure. It takes time on a home budget, but my personal goal of adding to the data will be accomplished soon. Proving or disproving, its all the same to me...I've enjoyed the build and commaraderie to date.
Absolutely no one, has ever replicated the claims of Shawyer and Yang (who never reported a single test performed in vacuum and therefore never properly accounted for thermal effects).
Yet another report from a DIY experiment showing NO thrust from an EM Drive and instead reporting thermal effects: https://www.reddit.com/r/EmDrive/comments/3kxvjr/emdrive_build_update_5/And you wonder why I'm being picky?
Absolutely no one, has ever replicated the claims of Shawyer and Yang (who never reported a single test performed in vacuum and therefore never properly accounted for thermal effects).
Yet another report from a DIY experiment showing NO thrust from an EM Drive and instead reporting thermal effects: https://www.reddit.com/r/EmDrive/comments/3kxvjr/emdrive_build_update_5/l
Absolutely no one, has ever replicated the claims of Shawyer and Yang (who never reported a single test performed in vacuum and therefore never properly accounted for thermal effects).
Yet another report from a DIY experiment showing NO thrust from an EM Drive and instead reporting thermal effects: https://www.reddit.com/r/EmDrive/comments/3kxvjr/emdrive_build_update_5/l
Absolutely no one, has ever replicated the claims of Shawyer and Yang (who never reported a single test performed in vacuum and therefore never properly accounted for thermal effects).
Well if I used dimensions meant for a 900mhz rf source with a 2.45ghz rf source to test a theory involving "and the Q is important" I'm not sure it bricking is going to tell me much useful information.
Yet another report from a DIY experiment showing NO thrust from an EM Drive and instead reporting thermal effects: https://www.reddit.com/r/EmDrive/comments/3kxvjr/emdrive_build_update_5/l
Absolutely no one, has ever replicated the claims of Shawyer and Yang (who never reported a single test performed in vacuum and therefore never properly accounted for thermal effects).
Well if I used dimensions meant for a 900mhz rf source with a 2.45ghz rf source to test a theory involving "and the Q is important" I'm not sure it bricking is going to tell me much useful information.
On the contrary, if a cavity of given dimensions resonates at a lower frequency, it will certainly also resonate at higher frequencies, and the higher the frequency the closer to each other (on a % basis) are the natural frequencies to each other.
Pick any one of the frequencies out of a consumer magnetron to start, but first figure out whether it's driven by a single HV diode @ 220 VAC 50 Hz or a 220 VAC Inverter @ 50 Hz (South Africa's power grid is 220VAC @ 50 Hz). If it's a single HV Diode PS driving it then the range for harmonics and shifting frequencies will be greater than a Inverter which operating frequencies should be on the order of 20 KHz into the HV coil and a more stable output.Yet another report from a DIY experiment showing NO thrust from an EM Drive and instead reporting thermal effects: https://www.reddit.com/r/EmDrive/comments/3kxvjr/emdrive_build_update_5/l
Absolutely no one, has ever replicated the claims of Shawyer and Yang (who never reported a single test performed in vacuum and therefore never properly accounted for thermal effects).
Well if I used dimensions meant for a 900mhz rf source with a 2.45ghz rf source to test a theory involving "and the Q is important" I'm not sure it bricking is going to tell me much useful information.
On the contrary, if a cavity of given dimensions resonates at a lower frequency, it will certainly also resonate at higher frequencies, and the higher the frequency the closer to each other (on a % basis) are the natural frequencies to each other.
What I learned this week:You have a schematic of your power supply?
Most replacement magnetrons have an advertised frequency center at 2460, not 2450.
A standard non-inverter microwave on 60hz power produces 4250v pulses at twice the line frequency, on for 8.3 ms, off for 8.3 ms.
With 2 caps and another diode you can replace the https://en.wikipedia.org/wiki/Voltage_doubler#Villard_circuit output stage with a https://en.wikipedia.org/wiki/Voltage_doubler#Greinacher_circuit . This provides continuous power output instead of pulsed.
You can use oven diodes for this, but the oven caps aren't rated for the voltage. I found 10kv film capacitors on ebay for <$25. For safety add bleeder resistors to these caps.
Now I have a new question: How can I further change the output voltage and/or current limit this? That's this week's project.
Thanks in advance for the advice.
What I learned this week:You have a schematic of your power supply?
Most replacement magnetrons have an advertised frequency center at 2460, not 2450.
A standard non-inverter microwave on 60hz power produces 4250v pulses at twice the line frequency, on for 8.3 ms, off for 8.3 ms.
With 2 caps and another diode you can replace the https://en.wikipedia.org/wiki/Voltage_doubler#Villard_circuit output stage with a https://en.wikipedia.org/wiki/Voltage_doubler#Greinacher_circuit . This provides continuous power output instead of pulsed.
You can use oven diodes for this, but the oven caps aren't rated for the voltage. I found 10kv film capacitors on ebay for <$25. For safety add bleeder resistors to these caps.
Now I have a new question: How can I further change the output voltage and/or current limit this? That's this week's project.
Thanks in advance for the advice.
Shell
[..]
I hope all realize I'm just using this forum as a sounding board for my half baked thoughts sometimes and what ifs or has anyone taken it into account.
Being half baked is a prudent path to avoid being burnt.
Sometimes it's hard to swallow half baked too.[..]
I hope all realize I'm just using this forum as a sounding board for my half baked thoughts sometimes and what ifs or has anyone taken it into account.
Being half baked is a prudent path to avoid being burnt.
Never!Hehe, haven't heard that one in 45 years Bob. And we know which one won that classic race, between the Tortoise and the Hare.
I can't claim to be a scientist as much as I would like to be able to. I did some ground breaking programming while in government. But few people saw the ground. ;D
You're probably as near old as me. Possibly you remember this from college:
"Behold the turtle. They only make progress when they stick their heads out."
(Revised to compensate for 1970's sexism.)
Bob
New emdrive build head's up:
https://www.reddit.com/r/EmDrive/comments/3l4clo/emdrive_build_update_version_001/
Interesting test bed configuration; he's just getting started. Laser powered rather than magnetron. A little different, but hey, everyone has a right to start somewhere. Should be interesting!
NSF-1701 Update: New LDS display meter on its way. Will be installing it into an old PC where I'll use its power supply to fire up the LDS and also DAQ inputs. The display is simply a good visual tool, the DAQ will give me the tabular data for chart creating, etc.
I also will be experimenting around with labview or its open source equivalent. Figure an old PC is fine for DAQ stuff, but am still cautious about relying on it too much in high EM fields...thus the shielded LDS display module which is designed to work in tough industrial environments, heat, vibration, EM fields, etc.,
Thanks! Will download this tonight. Have a 10=bit A/D module coming in as well as the new LDS display in a few days.New emdrive build head's up:
https://www.reddit.com/r/EmDrive/comments/3l4clo/emdrive_build_update_version_001/
Interesting test bed configuration; he's just getting started. Laser powered rather than magnetron. A little different, but hey, everyone has a right to start somewhere. Should be interesting!
NSF-1701 Update: New LDS display meter on its way. Will be installing it into an old PC where I'll use its power supply to fire up the LDS and also DAQ inputs. The display is simply a good visual tool, the DAQ will give me the tabular data for chart creating, etc.
I also will be experimenting around with labview or its open source equivalent. Figure an old PC is fine for DAQ stuff, but am still cautious about relying on it too much in high EM fields...thus the shielded LDS display module which is designed to work in tough industrial environments, heat, vibration, EM fields, etc.,
take a look at this: http://www.myopenlab.de/startseite/downloads.html
Documentation is in German and Spanish, but the installer permits a choice of English. If you speak German or Spanish, you're home free.
English forum: http://myopenlab.informe.com/myopenlab-english-df1.html
I found a nice youtube channel, sure that's already known, nevertheless quite interesting to see the pure mechanically conditions in such a simulation ;D
...
some more vids are available
OK, an extension:urk. You bet Bob, I'm not Shell Shocked.
Behold the oyster. You only get the pearl when the Shell opens up.
Find that thrust. Try and try again. Then repeat.
I found a nice youtube channel, sure that's already known, nevertheless quite interesting to see the pure mechanically conditions in such a simulation ;D
I found a nice youtube channel, sure that's already known, nevertheless quite interesting to see the pure mechanically conditions in such a simulation ;D
...
some more vids are available
Interesting video...
So all we have to do is pressurize a cone and heat it up, and we should get a net thrust? :o
@SeeShells,
Here are some views of the CE3 model. They are very preliminary but ... well, its as far as I have gotten.
https://drive.google.com/folderview?id=0B1XizxEfB23td2ZDeDFUUFdvLUk&usp=sharing (https://drive.google.com/folderview?id=0B1XizxEfB23td2ZDeDFUUFdvLUk&usp=sharing)
It resonates but it's not a mode that I recognize.
Specifics-
Cavity is the SeeShell Crazy Eddie 2, upgraded by replacing the loop antenna with wave guides, hence CE3 model.
Drive frequency 2.47 GHz, Harminv calculated resonant frequency 2.47837658E+009 Hz, Q is good: ~ 1 million.
Antenna - dual magnetron wave guides, 180 degrees apart. That is, on opposite sides of the frustum using WR 340 wave guides with bottom edge flush with the big base. Phase is adjusted to place sources 3 wavelengths apart.
Gaussian noise bandwidth at 0.05 * 2.47GHz is is double the expected magnetron noise bandwidth.
This is a debug run at resolution = 200, hence it may appear more granular than the resolution = 250 runs commonly uploaded. There are no csv files, resolution of 200 would adversely affect any data comparison calculations based on the csv files.
I might have been part of that ionized conversation. I noticed a metallic "feel" to the air after power testing which someone proposed as copper ionization. It could be Ni, but it seemed "metallic", if I might used that term. This was noticed on all 3 Flight Tests I did in August. FWIW, I know its not exactly a scientific description, just an impression.I found a nice youtube channel, sure that's already known, nevertheless quite interesting to see the pure mechanically conditions in such a simulation ;D
...
some more vids are available
Interesting video...
So all we have to do is pressurize a cone and heat it up, and we should get a net thrust? :o
Back in thread three this was discussed briefly in the context of ionized particles. Yang stated in one of her papers that the behaviour of ionized particles was important to understanding the behaviour of EM Drives. It has been pointed out numerous times that neither Yang or Shawyer published experiments ran in vacuum.
At one point I called this the "ionic wind tunnel" effect in those discussions. That said, these were general discussions and everyone felt that microwave energy was the primary source for trust...
Now we have some excellent simulations that bring this all back. Note that, say, nitrogen ions are orders of magnitude more massive than photons.
In my view, these simulations are a significant step forward in our understanding of this phenomena. Congratulations!
And once again I am in awe of the power of these forums! :D
Ni? Why Nickel?I might have been part of that ionized conversation. I noticed a metallic "feel" to the air after power testing which someone proposed as copper ionization. It could be Ni, but it seemed "metallic", if I might used that term. This was noticed on all 3 Flight Tests I did in August. FWIW, I know its not exactly a scientific description, just an impression.I found a nice youtube channel, sure that's already known, nevertheless quite interesting to see the pure mechanically conditions in such a simulation ;D
...
some more vids are available
Interesting video...
So all we have to do is pressurize a cone and heat it up, and we should get a net thrust? :o
Back in thread three this was discussed briefly in the context of ionized particles. Yang stated in one of her papers that the behaviour of ionized particles was important to understanding the behaviour of EM Drives. It has been pointed out numerous times that neither Yang or Shawyer published experiments ran in vacuum.
At one point I called this the "ionic wind tunnel" effect in those discussions. That said, these were general discussions and everyone felt that microwave energy was the primary source for trust...
Now we have some excellent simulations that bring this all back. Note that, say, nitrogen ions are orders of magnitude more massive than photons.
In my view, these simulations are a significant step forward in our understanding of this phenomena. Congratulations!
And once again I am in awe of the power of these forums! :D
Ooooops, N not Ni :oNi? Why Nickel?I might have been part of that ionized conversation. I noticed a metallic "feel" to the air after power testing which someone proposed as copper ionization. It could be Ni, but it seemed "metallic", if I might used that term. This was noticed on all 3 Flight Tests I did in August. FWIW, I know its not exactly a scientific description, just an impression.I found a nice youtube channel, sure that's already known, nevertheless quite interesting to see the pure mechanically conditions in such a simulation ;D
...
some more vids are available
Interesting video...
So all we have to do is pressurize a cone and heat it up, and we should get a net thrust? :o
Back in thread three this was discussed briefly in the context of ionized particles. Yang stated in one of her papers that the behaviour of ionized particles was important to understanding the behaviour of EM Drives. It has been pointed out numerous times that neither Yang or Shawyer published experiments ran in vacuum.
At one point I called this the "ionic wind tunnel" effect in those discussions. That said, these were general discussions and everyone felt that microwave energy was the primary source for trust...
Now we have some excellent simulations that bring this all back. Note that, say, nitrogen ions are orders of magnitude more massive than photons.
In my view, these simulations are a significant step forward in our understanding of this phenomena. Congratulations!
And once again I am in awe of the power of these forums! :D
Shell
Hmm...I found a nice youtube channel, sure that's already known, nevertheless quite interesting to see the pure mechanically conditions in such a simulation ;D
https://www.youtube.com/watch?v=MxhT5_Hh2CA
some more vids are available
1 - One of my first posts here (way back in thread one) dealt with this - that the EM Drive moved on account of its shape.
2 - I was told the concept violated the laws of thermodynamics. So, given that, are these simulations legit?
Ok, thought experiment. Say we use actual physical objects instead of photons. maybe old fashioned 'super balls' or something similar, though unlike photons they would slow down. A frustum in a zero G environment. Would the results match the simulation?
So, given that, are these simulations legit?
On the contrary, if a cavity of given dimensions resonates at a lower frequency, it will certainly also resonate at higher frequencies, and the higher the frequency the closer to each other (on a % basis) are the natural frequencies to each other.
@SeeShells,
Here are some views of the CE3 model. They are very preliminary but ... well, its as far as I have gotten.
https://drive.google.com/folderview?id=0B1XizxEfB23td2ZDeDFUUFdvLUk&usp=sharing (https://drive.google.com/folderview?id=0B1XizxEfB23td2ZDeDFUUFdvLUk&usp=sharing)
It resonates but it's not a mode that I recognize.
Specifics-
Cavity is the SeeShell Crazy Eddie 2, upgraded by replacing the loop antenna with wave guides, hence CE3 model.
Drive frequency 2.47 GHz, Harminv calculated resonant frequency 2.47837658E+009 Hz, Q is good: ~ 1 million.
Antenna - dual magnetron wave guides, 180 degrees apart. That is, on opposite sides of the frustum using WR 340 wave guides with bottom edge flush with the big base. Phase is adjusted to place sources 3 wavelengths apart.
Gaussian noise bandwidth at 0.05 * 2.47GHz is is double the expected magnetron noise bandwidth.
This is a debug run at resolution = 200, hence it may appear more granular than the resolution = 250 runs commonly uploaded. There are no csv files, resolution of 200 would adversely affect any data comparison calculations based on the csv files.
Great to see you got the waveguide injection working aero.
It looks like you placed the wave right on the bottom to replace the antennas,
If you look at the mode generation in the attached image...
You'll see close to the middle of the frustum is where the mode wants to generate within the frustum. Did you try to do the waveguides insertion at that point? We should try.
Shell
Move the waveguides up to the point where they are not inserting into the frustum which should be halfway up. See image.
Not quite zero aero, we are dealing in the Z direction with different issues in mode generation because of the asymmetry of the frustum. I'll need to search to find the equation Dr. Rodel used in determining the percentages. Search is hideous btw.@SeeShells,
Here are some views of the CE3 model. They are very preliminary but ... well, its as far as I have gotten.
https://drive.google.com/folderview?id=0B1XizxEfB23td2ZDeDFUUFdvLUk&usp=sharing (https://drive.google.com/folderview?id=0B1XizxEfB23td2ZDeDFUUFdvLUk&usp=sharing)
It resonates but it's not a mode that I recognize.
Specifics-
Cavity is the SeeShell Crazy Eddie 2, upgraded by replacing the loop antenna with wave guides, hence CE3 model.
Drive frequency 2.47 GHz, Harminv calculated resonant frequency 2.47837658E+009 Hz, Q is good: ~ 1 million.
Antenna - dual magnetron wave guides, 180 degrees apart. That is, on opposite sides of the frustum using WR 340 wave guides with bottom edge flush with the big base. Phase is adjusted to place sources 3 wavelengths apart.
Gaussian noise bandwidth at 0.05 * 2.47GHz is is double the expected magnetron noise bandwidth.
This is a debug run at resolution = 200, hence it may appear more granular than the resolution = 250 runs commonly uploaded. There are no csv files, resolution of 200 would adversely affect any data comparison calculations based on the csv files.
Great to see you got the waveguide injection working aero.
It looks like you placed the wave right on the bottom to replace the antennas,
If you look at the mode generation in the attached image...
You'll see close to the middle of the frustum is where the mode wants to generate within the frustum. Did you try to do the waveguides insertion at that point? We should try.
Shell
Move the waveguides up to the point where they are not inserting into the frustum which should be halfway up. See image.
Just to be clear on this point, the wave guides do not insert into the frustum. They are placed then cut cleanly at the inside surface of the frustum. The image shows that cut in the frustum cone as projected in the 2-D image of the 3-D object. Not sure how you would actually construct them that way, but it is quite easy to model.
As currently modelled the wave guides are offset in z from the frustum exact center by -3.852 mm toward the big base. That aligns the bottom inside surface of the WR 340 with the inside surface of the big base. I will change that offset to zero from the frustum center and see what happens.
Dr. Rodal, you lost me there. I thought that the EM-Drive/Q-Thruster phenomena was linked to the concept that the frustrum had to be at the exact resonance mode (i.e. a frustrum at TE013 at 900MHz would NOT be at TE013 at 2.45GHz and thus would NOT have the same thrust??). Is not a concern in these experiments the question of how exact do you have to be to achieve resonance mode as oppose to simply resonating (to fluidize the quantum vacuum or whatever)?? Indeed with our ANSYS modelling we are finding that the cavity part itself is not so hard, but we've found it to be non-trivial in the way the rf needs to be launched into the cavity.... more complicated is the fact that we want to be able to try firing RF into the large side and be able to switch to the smaller side... though I guess the easiest choice is into the side.
On the contrary, if a cavity of given dimensions resonates at a lower frequency, it will certainly also resonate at higher frequencies, and the higher the frequency the closer to each other (on a % basis) are the natural frequencies to each other.
As a backup to the digital meter made for the LDS, I am using a basic, 10-bit A/D converter. Here it is:
http://www.dataq.com/products/di-145/
This is a USB interface and easy to use. It measures up to +/- 10 VDC and the LDS is about +/- 5 VDC. It will datalog and can provide a simple graphic display on vertical displacement at a sample rate of about 4 msec (240 Hz).
...
Very nice summary! The LDS has a pre-filtered amp. The entire assembly is an Omron Z4M-W40 plus an Omron K3NX display. Here's a datasheet: http://www.limasoft.cz/omron/pdf/z4m.pdfAs a backup to the digital meter made for the LDS, I am using a basic, 10-bit A/D converter. Here it is:
http://www.dataq.com/products/di-145/
This is a USB interface and easy to use. It measures up to +/- 10 VDC and the LDS is about +/- 5 VDC. It will datalog and can provide a simple graphic display on vertical displacement at a sample rate of about 4 msec (240 Hz).
...
Great to hear about the 10-bit ADC DAQ!
I took the liberty to examine their datasheet, and I suspect the DI-145 analog inputs do not contain much low-pass filtering. I mention this as it can have a non-trivial impact on what ADC value gets generated for a given input (i.e. can get "noisy" digital output if there are frequencies greater than 120Hz in the real analog signal).
Adding a simple low-pass filter might not be a bad idea to help eliminate any aliasing noise and help guard against unknown setup/hold requirements of the ADC channel (i.e. set filter to a ~120 Hz cutoff). Also worth keeping in mind the 240Hz sampling rate is only valid for 1 analog channel; if there are additional analog channels, the 240Hz gets divided accordingly (i.e. 1 ch@240Hz, 2 ch@120Hz, 3 ch @ 80Hz, etc) so any pre-filter would also need to be adjusted.
As a quick primer for other lurkers, a key principal in DSP (Digital Signal Processing) is known as the Nyquist Sampling Theorem.
https://en.wikipedia.org/wiki/Nyquist%E2%80%93Shannon_sampling_theorem (https://en.wikipedia.org/wiki/Nyquist%E2%80%93Shannon_sampling_theorem)
The quick summary is that when converting analog into digital, you can only faithfully reconstruct the original analog signal if the digital signal is sampled at a rate at least twice as fast as the highest frequency in the original analog signal. Without the 2x sampling rate (digital sample vs analog freq), the digital signal won't contain all of the information from the original analog signal; worse yet, the higher frequency information can "alias" and masquerade as a lower frequency signal in the digital output. Since the DI-145 claims a 240Hz sampling rate, any frequency greater than 120Hz in the analog signal can result in aliasing. Pre-filtering the analog signal to eliminate the higher frequency content (i.e. >120Hz) will help avoid any alias-induced noise (although filters inevitably introduce distortion that must be accounted for; primarily a time-delay, but often also a small voltage drop due to losses in a passive filter circuit).
Thanks,
James
What is the relevance of resonating at an arbitrary mode shape like TE013? (Why would one choose TE013 instead of other mode shapes) ? ???@Rodal
What theory supports the choice of TE013? What is special about TE013? ???Dr. Rodal, you lost me there. I thought that the EM-Drive/Q-Thruster phenomena was linked to the concept that the frustrum had to be at the exact resonance mode (i.e. a frustrum at TE013 at 900MHz would NOT be at TE013 at 2.45GHz and thus would NOT have the same thrust??). Is not a concern in these experiments the question of how exact do you have to be to achieve resonance mode as oppose to simply resonating (to fluidize the quantum vacuum or whatever)?? Indeed with our ANSYS modelling we are finding that the cavity part itself is not so hard, but we've found it to be non-trivial in the way the rf needs to be launched into the cavity.... more complicated is the fact that we want to be able to try firing RF into the large side and be able to switch to the smaller side... though I guess the easiest choice is into the side.
On the contrary, if a cavity of given dimensions resonates at a lower frequency, it will certainly also resonate at higher frequencies, and the higher the frequency the closer to each other (on a % basis) are the natural frequencies to each other.
...
But what do you mean with "the higher the frequency the closer to each other"?
If you use dimensions 10 times smaller the total frequency difference between the modes is 10 times bigger ???
Example(random dimensions):
Dimensions bD=234mm sD=123mm Length=123mm
TE011=2,4543258071GHz
TE013=4,2396819866GHz
Dimensions bD=23.4mm sD=12.3mm Length=12.3mm
TE011= 24,5432580708GHz
TE013=42.3968198663GHz
And @All:
- The higher the mode the more sensitive it is against variation of the dimensions.
+The higher the mode(p value) the lower the BW.
The statement <<and the higher the frequency the closer to each other >>, obviously implies changing the excitation frequency and leaving everything else the same. That means,: same materials, same geometry, same boundary conditions, etc. Obviously, if you change any of the parameters affecting the frequency (you are arbitrarily changing the dimensions in your example below) then nothing can be said without knowing the arbitrary geometrical change you intend to make. The statement was made in the context of the experiment being discussed in the post that I was answering, in which it was implied that the geometry, materials, etc., remained the same and the only thing being changed was the excitation frequency.Agreed. Also for the post before "What is special about TE013? ???"...
But what do you mean with "the higher the frequency the closer to each other"?
If you use dimensions 10 times smaller the total frequency difference between the modes is 10 times bigger ???
Example(random dimensions):
Dimensions bD=234mm sD=123mm Length=123mm
TE011=2,4543258071GHz
TE013=4,2396819866GHz
Dimensions bD=23.4mm sD=12.3mm Length=12.3mm
TE011= 24,5432580708GHz
TE013=42.3968198663GHz
And @All:
- The higher the mode the more sensitive it is against variation of the dimensions.
+The higher the mode(p value) the lower the BW.
Not quite zero aero, we are dealing in the Z direction with different issues in mode generation because of the asymmetry of the frustum. I'll need to search to find the equation Dr. Rodel used in determining the percentages. Search is hideous btw.@SeeShells,
Here are some views of the CE3 model. They are very preliminary but ... well, its as far as I have gotten.
https://drive.google.com/folderview?id=0B1XizxEfB23td2ZDeDFUUFdvLUk&usp=sharing (https://drive.google.com/folderview?id=0B1XizxEfB23td2ZDeDFUUFdvLUk&usp=sharing)
It resonates but it's not a mode that I recognize.
Specifics-
Cavity is the SeeShell Crazy Eddie 2, upgraded by replacing the loop antenna with wave guides, hence CE3 model.
Drive frequency 2.47 GHz, Harminv calculated resonant frequency 2.47837658E+009 Hz, Q is good: ~ 1 million.
Antenna - dual magnetron wave guides, 180 degrees apart. That is, on opposite sides of the frustum using WR 340 wave guides with bottom edge flush with the big base. Phase is adjusted to place sources 3 wavelengths apart.
Gaussian noise bandwidth at 0.05 * 2.47GHz is is double the expected magnetron noise bandwidth.
This is a debug run at resolution = 200, hence it may appear more granular than the resolution = 250 runs commonly uploaded. There are no csv files, resolution of 200 would adversely affect any data comparison calculations based on the csv files.
Great to see you got the waveguide injection working aero.
It looks like you placed the wave right on the bottom to replace the antennas,
If you look at the mode generation in the attached image...
You'll see close to the middle of the frustum is where the mode wants to generate within the frustum. Did you try to do the waveguides insertion at that point? We should try.
Shell
Move the waveguides up to the point where they are not inserting into the frustum which should be halfway up. See image.
Just to be clear on this point, the wave guides do not insert into the frustum. They are placed then cut cleanly at the inside surface of the frustum. The image shows that cut in the frustum cone as projected in the 2-D image of the 3-D object. Not sure how you would actually construct them that way, but it is quite easy to model.
As currently modelled the wave guides are offset in z from the frustum exact center by -3.852 mm toward the big base. That aligns the bottom inside surface of the WR 340 with the inside surface of the big base. I will change that offset to zero from the frustum center and see what happens.
I know that the mode TE011 and TE013 have the same EMF cross sections and I could have done TE011 or a TE013 which I seriously looked at, but the ceramic plate sizes I had available TE012 was easier for me to do. Also a TE012 mode was the goal with RS in the EMDrive he made for Boeing and also a goal for EW when they were trying to get thrust. It was an obvious choice with the materials I could get.The statement <<and the higher the frequency the closer to each other >>, obviously implies changing the excitation frequency and leaving everything else the same. That means,: same materials, same geometry, same boundary conditions, etc. Obviously, if you change any of the parameters affecting the frequency (you are arbitrarily changing the dimensions in your example below) then nothing can be said without knowing the arbitrary geometrical change you intend to make. The statement was made in the context of the experiment being discussed in the post that I was answering, in which it was implied that the geometry, materials, etc., remained the same and the only thing being changed was the excitation frequency.Agreed. Also for the post before "What is special about TE013? ???"...
But what do you mean with "the higher the frequency the closer to each other"?
If you use dimensions 10 times smaller the total frequency difference between the modes is 10 times bigger ???
Example(random dimensions):
Dimensions bD=234mm sD=123mm Length=123mm
TE011=2,4543258071GHz
TE013=4,2396819866GHz
Dimensions bD=23.4mm sD=12.3mm Length=12.3mm
TE011= 24,5432580708GHz
TE013=42.3968198663GHz
And @All:
- The higher the mode the more sensitive it is against variation of the dimensions.
+The higher the mode(p value) the lower the BW.
:)
Tangent - First Orion Spacecraft Manned Flight?No bucks, no buck rogers.
2023...8 years from now.
Almost as long as it took us to start the space program and land a man on the moon.
Sometimes I wonder.
Good thought, although if you look closely, there is a large budget still available. Not being an insider, it appears a lot of it is earmarked for climate observations, PR and aeronautical applications. If I recall the 60s correctly (OK, so I was a kid), it seemed like NASA went aeronautical in order to advance to space. We have done this already.Tangent - First Orion Spacecraft Manned Flight?No bucks, no buck rogers.
2023...8 years from now.
Almost as long as it took us to start the space program and land a man on the moon.
Sometimes I wonder.
@SeeShellsThe waveguide you laid out is a rectangular guide and I hope following the WR340 sizing. The central axis or longer axis of the waveguide should be along the Z axis centered to the Z center-line.
Here are 3 data points showing Q variation with wave guide offset from the center of the frustum toward the big end. Q is plotted as log10 values and z values are in millimeters.
Note that the model has the central axis of the wave guide parallel to the plane of the frustum bases, not perpendicular to the conic side wall. Is that an issue?
@SeeShellsThe waveguide you laid out is a rectangular guide and I hope following the WR340 sizing. The central axis or longer axis of the waveguide should be along the Z axis centered to the Z center-line.
Here are 3 data points showing Q variation with wave guide offset from the center of the frustum toward the big end. Q is plotted as log10 values and z values are in millimeters.
Note that the model has the central axis of the wave guide parallel to the plane of the frustum bases, not perpendicular to the conic side wall. Is that an issue?
Not at a angle like the Dresden run but the waveguide should be parallel to the top and bottom plate. They got the orientation correct.
I know that the mode TE011 and TE013 have the same EMF cross sections and I could have done TE011 or a TE013 which I seriously looked at, but the ceramic plate sizes I had available TE012 was easier for me to do. Also a TE012 mode was the goal with RS in the EMDrive he made for Boeing and also a goal for EW when they were trying to get thrust. It was an obvious choice with the materials I could get.The statement <<and the higher the frequency the closer to each other >>, obviously implies changing the excitation frequency and leaving everything else the same. That means,: same materials, same geometry, same boundary conditions, etc. Obviously, if you change any of the parameters affecting the frequency (you are arbitrarily changing the dimensions in your example below) then nothing can be said without knowing the arbitrary geometrical change you intend to make. The statement was made in the context of the experiment being discussed in the post that I was answering, in which it was implied that the geometry, materials, etc., remained the same and the only thing being changed was the excitation frequency.Agreed. Also for the post before "What is special about TE013? ???"...
But what do you mean with "the higher the frequency the closer to each other"?
If you use dimensions 10 times smaller the total frequency difference between the modes is 10 times bigger ???
Example(random dimensions):
Dimensions bD=234mm sD=123mm Length=123mm
TE011=2,4543258071GHz
TE013=4,2396819866GHz
Dimensions bD=23.4mm sD=12.3mm Length=12.3mm
TE011= 24,5432580708GHz
TE013=42.3968198663GHz
And @All:
- The higher the mode the more sensitive it is against variation of the dimensions.
+The higher the mode(p value) the lower the BW.
:)
Shell
I can support wallofwolfstreet's comment that these so called "simulations" do not represent a real physics process.Hmm...I found a nice youtube channel, sure that's already known, nevertheless quite interesting to see the pure mechanically conditions in such a simulation ;D
https://www.youtube.com/watch?v=MxhT5_Hh2CA
some more vids are available
1 - One of my first posts here (way back in thread one) dealt with this - that the EM Drive moved on account of its shape.
2 - I was told the concept violated the laws of thermodynamics. So, given that, are these simulations legit?
Ok, thought experiment. Say we use actual physical objects instead of photons. maybe old fashioned 'super balls' or something similar, though unlike photons they would slow down. A frustum in a zero G environment. Would the results match the simulation?
To answer your question:QuoteSo, given that, are these simulations legit?
No, these simulations are not legit. A frustum in a zero G environment would not have results that match the simulation.
Exactly what when wrong in the simulation, I couldn't say without seeing everything he did to the settings, etc. But the results are completely nonphysical and don't correspond to the real world.
Just intuitively, a bunch of non-zero momentum particles bouncing around in an asymetric cavity isn't a rare system. Such systems exist everywhere. Even the most energetic photons have negligible momentum if we compare them to your average gas particle at STP. So if this simulation was legitimate (which it isn't), then a coke bottle filled with air or your average household balloon ought to be rocketing around with orders of magnitude better thrust than an emdrive.
I'm not going to take the time to flesh out the solution to such a problem mathematically, but it isn't difficult. The case of infinitely many particles is equivalent to the uniform pressure case, and a person only needs some trig to be able to solve it. In fact, the intuition of the problem is simple and shows the issue with what the youtube poster believes is happening.
In the video, he says that because the walls of the cone are angled off the plane of the horizontally flat base, only some of the force they experience when struck by a particle is in the vertical direction. This is correct, but it does not lead to any net movement in the vertical direction because the angled walls also have a greater area than the horizontal base. While one bounce against the flat base creates a greater vertical force than a bounce off the angled side walls, the fact that there is greater chance to hit a side wall than there is the top base due to the greater area perfectly cancels, so there is no net force over time.
If that wasn't enough, also realize that the simulation showed the drive moving towards the direction of the "big" base, which is opposite the direction the emdrive is supposed to go.
So if anything, these simulations are a case study in how you need to have a proper understanding of first principles to tell whether or not your simulations are correct.
There is a distinct difference between an animation and a simulation:Absolutely right. The focus of these applications is to provide the appearance of real materials, not to simulate them on every level. Depending on the strength of the program, simple properties like density can be well represented, but even properties that affect physical transformation — say, something like ductility — may be poor to nonexistent.
An animation is designed with a certain intend. Their dynamics module is not designed for physical accuracy, but for efficiency and speed, consequently, these processes are hugely simplified.
From the outside they do appear to be simulations, but in reality , they're not...
I know that the mode TE011 and TE013 have the same EMF cross sections and I could have done TE011 or a TE013 which I seriously looked at, but the ceramic plate sizes I had available TE012 was easier for me to do. Also a TE012 mode was the goal with RS in the EMDrive he made for Boeing and also a goal for EW when they were trying to get thrust. It was an obvious choice with the materials I could get.The statement <<and the higher the frequency the closer to each other >>, obviously implies changing the excitation frequency and leaving everything else the same. That means,: same materials, same geometry, same boundary conditions, etc. Obviously, if you change any of the parameters affecting the frequency (you are arbitrarily changing the dimensions in your example below) then nothing can be said without knowing the arbitrary geometrical change you intend to make. The statement was made in the context of the experiment being discussed in the post that I was answering, in which it was implied that the geometry, materials, etc., remained the same and the only thing being changed was the excitation frequency.Agreed. Also for the post before "What is special about TE013? ???"...
But what do you mean with "the higher the frequency the closer to each other"?
If you use dimensions 10 times smaller the total frequency difference between the modes is 10 times bigger ???
Example(random dimensions):
Dimensions bD=234mm sD=123mm Length=123mm
TE011=2,4543258071GHz
TE013=4,2396819866GHz
Dimensions bD=23.4mm sD=12.3mm Length=12.3mm
TE011= 24,5432580708GHz
TE013=42.3968198663GHz
And @All:
- The higher the mode the more sensitive it is against variation of the dimensions.
+The higher the mode(p value) the lower the BW.
:)
Shell
It was RS who told me SPR now use TE013 for their work. He encouraged me to design for TE103. As I understand it, the spherical end plate, narrow Rf bandwidth based Boeing Flight Thruster was a TE013 design.
All the SC EMDrive stuff produced by RS since the Flight Thruster, uses Rf injection in the middle of the frustum side wall, which would inject the Rf into the middle lode of the 3 lobes of the TE013 mode. Also means at that injection point, it is the same / equal guide wavelength to/from both end plates.
I suspect doing it this way would reduce phase distortion from the Rf injection, on the already resonant standing wave, and increase the effective antenna coupling factor, lifting the loaded / operational Q value toward the max unloaded Q value.
Doing the Rf injection bursts of 20% of 1 TC would allow the post Rf injection resonant standing wave to form without injection induced phase distortion and lift post injection Force generation from the resultant higher Q. It may be that the low cost magnetrons use of pulsed 1/2 wave DC may induce this condition at the end of each 1/2 cycle of Rf energy being injected. Additionally the naturally pulsed magnetron output may again trigger multiple of this post no excitation increased Force generation event during each 1/2 on cycle.
What is the relevance of resonating at an arbitrary mode shape like TE013? (Why would one choose TE013 instead of other mode shapes) ?
It was RS who told me SPR now use TE013 for their work. He encouraged me to design for TE103. As I understand it, the spherical end plate, narrow Rf bandwidth based Boeing Flight Thruster was a TE013 design.
All the SC EMDrive stuff produced by RS since the Flight Thruster, uses Rf injection in the middle of the frustum side wall, which would inject the Rf into the middle lode of the 3 lobes of the TE013 mode. Also means at that injection point, it is the same / equal guide wavelength to/from both end plates.
I suspect doing it this way would reduce phase distortion from the Rf injection, on the already resonant standing wave, and increase the effective antenna coupling factor, lifting the loaded / operational Q value toward the max unloaded Q value.
Doing the Rf injection bursts of 20% of 1 TC would allow the post Rf injection resonant standing wave to form without injection induced phase distortion and lift post injection Force generation from the resultant higher Q. It may be that the low cost magnetrons use of pulsed 1/2 wave DC may induce this condition at the end of each 1/2 cycle of Rf energy being injected. Additionally the naturally pulsed magnetron output may again trigger multiple of this post no excitation increased Force generation event during each 1/2 on cycle.
Dr. Rodal, concern wasn't what mode (TE013 was picked at random as discussed below), but why you would think the mode is irrelevant so long as the cavity is resonating per your comment:
"On the contrary, if a cavity of given dimensions resonates at a lower frequency, it will certainly also resonate at higher frequencies, and the higher the frequency the closer to each other (on a % basis) are the natural frequencies to each other."
You seem to imply that if you have a cavity sized for say for 900MHz at TE013 (or whatever mode you think is optimal for thrust) that at 2.45GHz it is resonating anyway and thus should see the same thrust generation leading one to believe that mode is irrelevant (which I thought was not the case).
Are not researchers such as NASA Eagleworks trying to excite resonance modes as opposed to simply induce resonance. TE013 was an example. Clearly a frustrum with dimensions sized for TE013 at 900MHz would NOT be at TE013 at 2.45GHz... just as a TM014 (or TE012, or whatever mode your choose) frustrum with dimensions sized for 900MHz would NOT be at TM014 (or TE012, or whatever mode your choose) at 2.45GHz.
The importance of the question is clear in that if mode is irrelevant than why would researchers bother calculating the modes and trying to target modes with respect to thrust generation??
Based on all the talk of modes if the Q-Thruster/EM-Drive I thought researchers are linking thrust generation with reaching target modes, not asking is mode relevant but what is the optimum resonance mode and questions as to why mode matters as opposed to "who cares about mode as long as your resonating?"
Examples are evident in the research publications
"Using finite element numerical method to numerical analyse the classical Maxwell equation of electric field of the idealised conical resonator, to obtain the model and practical of the distribution of the electric field of the cavity under 1000W. By analyse the properties under different modes and the different properties. Calculation show that under the four modes, TE011, TE012, TE111 and TM011, the quality factor of TE012 is highest and with highest thrust, followed by TE011. - Chinese Paper
NASA was targeting with the "proposed" 100kW thruster I think TM010 which I assume is the optimal mode they are targeting (i.e. 100kW with a 9in H, 6.25in Small D, 11.01 in Large D unit at 957Hz seems to be sized for TM010)?
Choice of TE013 was arbitrary as in another forum I am asking the question of at 930MHz why we would want to size the frustrum for TE013 vs. TE012 vs the TM010 picked by NASA. That's the real question in my mind, why one mode over another, not - "frustrum is resonating, so should see thrust regardless of mode" as implied that a frustrum designed for a mode at 900MHz should see thrust at 2.45GHz simply because its resonating.What is the relevance of resonating at an arbitrary mode shape like TE013? (Why would one choose TE013 instead of other mode shapes) ?
TE013 or TE103?
I guess our modelling is showing that it is difficult to put in the RF from the waveguide launcher into the top or bottom and they too want to put it in the side and mentioned TE013 (and ironically this was for a pulsed test).
Anyone think that TE013 would be optimum for "thrust generation" reasons (though I suppose better Q-factor is reason enough?)?
It was RS who told me SPR now use TE013 for their work. He encouraged me to design for TE103. As I understand it, the spherical end plate, narrow Rf bandwidth based Boeing Flight Thruster was a TE013 design.
...
NSF-1701 update - Thanks to donations, I was able to afford an inexpensive thermal camera which I ordered today. Will be using it for magnetron and frustum viewing under power to try and understand heat sources. The larger than expected thermal lift characteristics while using mesh sidewalls has me a bit perplexed.
The magnetron and additional heatsink are above the frustum assembly and shouldn't be contributing to lift, unless its generating upwards air currents that "lift" the lower assembly upwards. I had expected cooler air to rush in at 90 degrees to the magnetron, not lifting it from underneath.
So...my focus will be on the cavity itself to see how fast and how much it heats up. I have not measured much thermal rise on the frustum (with a spot IR thermometer) once power is removed. A bit puzzling.
Thanks to all who are helping. $ as they come in are going directly to test gear. Happy wife...happy life.
Mr. Pichach, the literature points out that there is NO particular mode shape that is predicted to provide more thrust. On the contrary:
1) NASA Eagleworks is the only testing organization that has actually experimentally verified the mode shape that they excited: it was TM212, which is not even a TE mode. Nobody else has experimentally verified what mode shape was excited. Talk about mode shapes by others (except NASA Eagleworks) is just that: talk, and it cannot be scientifically accepted as corroboration of a any mode shape, particularly when Finite Element and exact solution analysis shows that there are several mode shapes in the frequency range of testing.
2) Neither R. Shawyer nor Prof.. Yang ever conducted a single test in a partial vacuum. Their test claims have NOT been replicated by any scientific organization whatsoever. If anything, the tests at TU Dresden and at NASA Eagleworks (resulting in thrust force/InputPower that are orders of magnitude smaller than the claims of Shawyer and Yang) have served as a scientific refutation of the claims by Shawyer and Yang, that one must objectively (in light of experiemental attempts at replication) to be subject to the well known "gas effect" (thermal convection, etc.) that has been known to plague all experimental measurements of electromagnetic pressure ever since it was predicted by Maxwell.
Sure can! No pun intended 8)NSF-1701 update - Thanks to donations, I was able to afford an inexpensive thermal camera which I ordered today. Will be using it for magnetron and frustum viewing under power to try and understand heat sources. The larger than expected thermal lift characteristics while using mesh sidewalls has me a bit perplexed.
The magnetron and additional heatsink are above the frustum assembly and shouldn't be contributing to lift, unless its generating upwards air currents that "lift" the lower assembly upwards. I had expected cooler air to rush in at 90 degrees to the magnetron, not lifting it from underneath.
So...my focus will be on the cavity itself to see how fast and how much it heats up. I have not measured much thermal rise on the frustum (with a spot IR thermometer) once power is removed. A bit puzzling.
Thanks to all who are helping. $ as they come in are going directly to test gear. Happy wife...happy life.
Can you use the thermal camera, as done by NASA Eagleworks to look into the flat ends and thereby verify what mode shape (if any) is being excited?
Just a thought on mode. I think the EMDrive might be a form of reflected energy thruster. (Similar to a photononic laser thruster). Something massless and traveling at the speed of light is, somehow, exiting the drive and being reflected back for additional bounces. Instead of a mirror we are using some kind of electromagnetic effect that reflects photons and is moving away from the drive opposite the direction of travel.
So that got me wondering, could there be some form of "ghost lobes" outside the drive that extend the resonance pattern we are seeing inside it.
This is probably better off on reddit than here, but here goes anyway:
Let me make a prediction about that Yang/Shell. I bet that if you animate it, it would look like lobes form at the small baseplate, and exit the frustum at the large plate. Let me also go out on a limb and suggest that a successful EMDrive will be one who's geometry causes causes the photons in the lobes (or at least some of them) to hit at greater than the critical angle to create an evanescent wave, and then resonance (i.e. bouncing off the end plate) is somehow maintained on the other side of the plate
If we don't need to target shape modes, yet the "EM-Drive/Q-Thruster" phenomena only occurs at a particular frequency for a particular dimension than isn't it amazing we've managed to find anything at all? Indeed is not the logical experiment than to fire RF all across the spectrum for a dimension and see if, when and where we see thrust given all bets are off as to when we see something (and given anything seen was basically completely by chance?!?!?)
Just a thought on mode. I think the EMDrive might be a form of reflected energy thruster. (Similar to a photononic laser thruster). Something massless and traveling at the speed of light is, somehow, exiting the drive and being reflected back for additional bounces. Instead of a mirror we are using some kind of electromagnetic effect that reflects photons and is moving away from the drive opposite the direction of travel.
Well, there is the thought/claim that evanescent waves stay attached, looping outward and back, redepositing their energy.Quote
So that got me wondering, could there be some form of "ghost lobes" outside the drive that extend the resonance pattern we are seeing inside it.
This is probably better off on reddit than here, but here goes anyway:
Let me make a prediction about that Yang/Shell. I bet that if you animate it, it would look like lobes form at the small baseplate, and exit the frustum at the large plate. Let me also go out on a limb and suggest that a successful EMDrive will be one who's geometry causes causes the photons in the lobes (or at least some of them) to hit at greater than the critical angle to create an evanescent wave, and then resonance (i.e. bouncing off the end plate) is somehow maintained on the other side of the plate
I've mentioned this idea before, but it needs some math backing to be taken seriously. I wonder if the evanescent photons escape the cavity by a tunnelling-like mechanism at superluminal velocity, then loop back to the cavity at light speed. It is only during the tunnelling process that the photons are superluminal carrying superluminal momentum (JMO).
That idea leaves open more than one idea for the thrust creation. It could be simply momentum variation of the evanescent photons, as I allude above, or perhaps the exchange of energy mass from the inside to outside results in a gravitational effect on the cavity. But I am not competent to broach this subject mathematically.
If we don't need to target shape modes, yet the "EM-Drive/Q-Thruster" phenomena only occurs at a particular frequency for a particular dimension than isn't it amazing we've managed to find anything at all? Indeed is not the logical experiment than to fire RF all across the spectrum for a dimension and see if, when and where we see thrust given all bets are off as to when we see something (and given anything seen was basically completely by chance?!?!?)
Well, given the use of a noisy magnetron. . .
Just a thought on mode. I think the EMDrive might be a form of reflected energy thruster. (Similar to a photononic laser thruster). Something massless and traveling at the speed of light is, somehow, exiting the drive and being reflected back for additional bounces. Instead of a mirror we are using some kind of electromagnetic effect that reflects photons and is moving away from the drive opposite the direction of travel.
Well, there is the thought/claim that evanescent waves stay attached, looping outward and back, redepositing their energy.Quote
So that got me wondering, could there be some form of "ghost lobes" outside the drive that extend the resonance pattern we are seeing inside it.
This is probably better off on reddit than here, but here goes anyway:
Let me make a prediction about that Yang/Shell. I bet that if you animate it, it would look like lobes form at the small baseplate, and exit the frustum at the large plate. Let me also go out on a limb and suggest that a successful EMDrive will be one who's geometry causes causes the photons in the lobes (or at least some of them) to hit at greater than the critical angle to create an evanescent wave, and then resonance (i.e. bouncing off the end plate) is somehow maintained on the other side of the plate
I've mentioned this idea before, but it needs some math backing to be taken seriously. I wonder if the evanescent photons escape the cavity by a tunnelling-like mechanism at superluminal velocity, then loop back to the cavity at light speed. It is only during the tunnelling process that the photons are superluminal carrying superluminal momentum (JMO).
That idea leaves open more than one idea for the thrust creation. It could be simply momentum variation of the evanescent photons, as I allude above, or perhaps the exchange of energy mass from the inside to outside results in a gravitational effect on the cavity. But I am not competent to broach this subject mathematically.
So um, stick an RF detector where we thinking this might be happening (which is hopefully not nanometers from the plate). If it goes off thing get interesting.
If we don't need to target shape modes, yet the "EM-Drive/Q-Thruster" phenomena only occurs at a particular frequency for a particular dimension than isn't it amazing we've managed to find anything at all? Indeed is not the logical experiment than to fire RF all across the spectrum for a dimension and see if, when and where we see thrust given all bets are off as to when we see something (and given anything seen was basically completely by chance?!?!?)
Well, given the use of a noisy magnetron. . .
And I wonder what happened to Dr. Notsosureofit's theory which did consider mode shapes? Is his theory now falsified?
Dr. Rodal, the ramifications of your claim that mode shape does not impact potential thrust are huge in my opinion.
Why do you think the NASA Eagleworks experiment then saw thrust at one particular frequency for one particular dimension that happened to be a shape mode?
Do you still agree that you need to target one or certain frequencies for certain frustrum dimensions to see EM-Drive/Q-Thruster phenomena but it isn't a shape mode as we define it or are you saying that its just resonance or the effect simply doesn't exist at all so it all doesn't matter?
If we don't need to target shape modes, yet the "EM-Drive/Q-Thruster" phenomena only occurs at a particular frequency for a particular dimension than isn't it amazing we've managed to find anything at all? Indeed is not the logical experiment than to fire RF all across the spectrum for a dimension and see if, when and where we see thrust given all bets are off as to when we see something (and given anything seen was basically completely by chance?!?!?) i.e. Was Paul March wasting his time coming up with all those shape modes?
What happened to all the talk on "thrust force measurements are related to the TRANSVERSE ELECTRIC modes, since their mode shape result in greater thrust force/PowerInput than the TRANSVERSE MAGNETIC mode shapes."
Would you agree that this is a fundamental shift in even your original thinking - I mean why did you come up with an exact solution for shape modes then relating to Q-Thruster/EM-Drive?
(Side note - huge ramifications if resonance shape and just resonance explains "thrust" with respect to Eagleworks claims to magnetohydrodynamics and QV fluidization at work).Mr. Pichach, the literature points out that there is NO particular mode shape that is predicted to provide more thrust. On the contrary:
1) NASA Eagleworks is the only testing organization that has actually experimentally verified the mode shape that they excited: it was TM212, which is not even a TE mode. Nobody else has experimentally verified what mode shape was excited. Talk about mode shapes by others (except NASA Eagleworks) is just that: talk, and it cannot be scientifically accepted as corroboration of a any mode shape, particularly when Finite Element and exact solution analysis shows that there are several mode shapes in the frequency range of testing.
2) Neither R. Shawyer nor Prof.. Yang ever conducted a single test in a partial vacuum. Their test claims have NOT been replicated by any scientific organization whatsoever. If anything, the tests at TU Dresden and at NASA Eagleworks (resulting in thrust force/InputPower that are orders of magnitude smaller than the claims of Shawyer and Yang) have served as a scientific refutation of the claims by Shawyer and Yang, that one must objectively (in light of experiemental attempts at replication) to be subject to the well known "gas effect" (thermal convection, etc.) that has been known to plague all experimental measurements of electromagnetic pressure ever since it was predicted by Maxwell.
If we don't need to target shape modes, yet the "EM-Drive/Q-Thruster" phenomena only occurs at a particular frequency for a particular dimension than isn't it amazing we've managed to find anything at all? Indeed is not the logical experiment than to fire RF all across the spectrum for a dimension and see if, when and where we see thrust given all bets are off as to when we see something (and given anything seen was basically completely by chance?!?!?)
Well, given the use of a noisy magnetron. . .
And I wonder what happened to Dr. Notsosureofit's theory which did consider mode shapes? Is his theory now falsified?
ALL of NASA Eagleworks experiments in vacuum have been performed with only (1) one mode shape: TM212
Nope, just waiting for data.
Dr. Rodal,
I'm not saying your wrong, I just want to ensure understanding.
To come right down to it, do you believe that NASA Eagleworks targeting a mode shape is a mistake and that we should be targeting dimensions @ frequencies based on another concept?
I think that is huge if it turns out that thrust is independent of mode shape; and I'd urge experiments to determine just when/where do we see thrust at dimensions @ frequencies regardless of mode shape.ALL of NASA Eagleworks experiments in vacuum have been performed with only (1) one mode shape: TM212
How can one make ANY scientifcally valid statements about "thrust" for other mode shapes when NASA has performed all their experiments in vacuum using just (1) one mode shape ???
and ONLY NASA has experimentally verified the mode shape???
and ONLY NASA and TU Dresden have reported experiments in vacuum ??? (but TU Dresden did not experimentally verify what mode shape was excited)
(as discussed NOBODY else has bothered to experimentally verify the mode shape excited)Dr. Rodal,
I'm not saying your wrong, I just want to ensure understanding.
To come right down to it, do you believe that NASA Eagleworks targeting a mode shape is a mistake and that we should be targeting dimensions @ frequencies based on another concept?
I think that is huge if it turns out that thrust is independent of mode shape; and I'd urge experiments to determine just when/where do we see thrust at dimensions @ frequencies regardless of mode shape.ALL of NASA Eagleworks experiments in vacuum have been performed with only (1) one mode shape: TM212
Unfortunately it will go off, otherwise the DYI'ers wouldn't be challenged with EM interference issues.
I can support wallofwolfstreet's comment that these so called "simulations" do not represent a real physics process.
Professionally, I'm using a similar 3D program with an almost identical rigid & softbody dynamics module.
The confusing originates from the arbitrary use of the word "simulation".
There is a distinct difference between an animation and a simulation:
An animation is designed with a certain intend. Their dynamics module is not designed for physical accuracy, but for efficiency and speed, consequently, these processes are hugely simplified.
From the outside they do appear to be simulations, but in reality , they're not...
A simulation uses genuine physics data and formulas in an attempt to replicate real events. It has no intend. There are software packages that are capable of simulating real natural events (fluid dynamics, nuclear explosion, etc) but these usually need a massive amount of computing power for days.
These 3D packages are all ANIMATION software packages, designed to make or support story telling.
Their dynamic modules are designed to be near real time and do cut a lot of corners to achieve that.
Sadly, animations are often disguised and sold as "simulations", because those carry a lot more public credibility, because they're used in the scientific, industrial and military world.
Bottom line:
I would not base any scientific conclusion based on the dynamics engine you find in Maya, 3DStudio, Softimage, etc.
Their proper use of those software packages is to make wonderful renders of how the EMdrive spaceship IXS Clark would/could look like...To tell a story, to spark imagination....
not to simulate a difficult and complex physics problem...
Good morning guys. Been following some of this since the article was published on site, but saw it referenced in a advanced concept meeting yesterday. Nothing specific, but direct mention and a reference to this site. Would anyone be kind enough to proivde a one post overview of current status per your testing and evaluations?The wiki page may be of interest :)
Good morning guys. Been following some of this since the article was published on site, but saw it referenced in a advanced concept meeting yesterday. Nothing specific, but direct mention and a reference to this site. Would anyone be kind enough to provide a one post overview of current status per your testing and evaluations?
Good morning guys. Been following some of this since the article was published on site, but saw it referenced in a advanced concept meeting yesterday. Nothing specific, but direct mention and a reference to this site. Would anyone be kind enough to proivde a one post overview of current status per your testing and evaluations?Sure.
Good morning guys. Been following some of this since the article was published on site, but saw it referenced in a advanced concept meeting yesterday. Nothing specific, but direct mention and a reference to this site. Would anyone be kind enough to proivde a one post overview of current status per your testing and evaluations?Welcome to the forum! My build/testing videos are here:
@rfmwguy did you ever witness any ionized air glow inside your see through frustum?No, but I noticed the BeO ceramic on the mag radome glowing. I also noted an "air" of metallic-like feel around it. Some commented it may be ionized copper.
@rfmwguy did you ever witness any ionized air glow inside your see through frustum?No, but I noticed the BeO ceramic on the mag radome glowing. I also noted an "air" of metallic-like feel around it. Some commented it may be ionized copper.
@rfmwguy did you ever witness any ionized air glow inside your see through frustum?No, but I noticed the BeO ceramic on the mag radome glowing. I also noted an "air" of metallic-like feel around it. Some commented it may be ionized copper.
But I'm looking for Cherenkov radiation from superluminal evanescent photons. Of course, being photons, they might not radiate other photons.
@rfmwguy did you ever witness any ionized air glow inside your see through frustum?No, but I noticed the BeO ceramic on the mag radome glowing. I also noted an "air" of metallic-like feel around it. Some commented it may be ionized copper.
But I'm looking for Cherenkov radiation from superluminal evanescent photons. Of course, being photons, they might not radiate other photons.
I can understand this type of radiation for particles with restmass traveling faster than light in a medium like "hot" neutrons in water.
You're realy looking for photons who emit photons ??? ?
Thanks for refreshing my memory, you are right! ::)@rfmwguy did you ever witness any ionized air glow inside your see through frustum?No, but I noticed the BeO ceramic on the mag radome glowing. I also noted an "air" of metallic-like feel around it. Some commented it may be ionized copper.
But I'm looking for Cherenkov radiation from superluminal evanescent photons. Of course, being photons, they might not radiate other photons.
I can understand this type of radiation for particles with restmass traveling faster than light in a medium like "hot" neutrons in water.
You're realy looking for photons who emit photons ??? ?
Neutrons and photons do not produce Cherenkov radiation. Charged particles such as electrons produce Cherenkov radiation when move they through a medium at a speed higher than the speed of light in that medium.
We're not going to see that in an EM drive.
Quote rom @flybyThere is a distinct difference between an animation and a simulation:Absolutely right. The focus of these applications is to provide the appearance of real materials, not to simulate them on every level. Depending on the strength of the program, simple properties like density can be well represented, but even properties that affect physical transformation — say, something like ductility — may be poor to nonexistent.
An animation is designed with a certain intend. Their dynamics module is not designed for physical accuracy, but for efficiency and speed, consequently, these processes are hugely simplified.
From the outside they do appear to be simulations, but in reality , they're not...
There's just enough in the best animation systems to fool you into believing they model reality, and not a penny more. I've yet to run into one that could adequately model the behavior of simple projectiles in air, much less an EM drive.
Have not followed this subtopic close enough to understand what other effects besides thermal might be occurring.Quote rom @flybyThere is a distinct difference between an animation and a simulation:Absolutely right. The focus of these applications is to provide the appearance of real materials, not to simulate them on every level. Depending on the strength of the program, simple properties like density can be well represented, but even properties that affect physical transformation — say, something like ductility — may be poor to nonexistent.
An animation is designed with a certain intend. Their dynamics module is not designed for physical accuracy, but for efficiency and speed, consequently, these processes are hugely simplified.
From the outside they do appear to be simulations, but in reality , they're not...
There's just enough in the best animation systems to fool you into believing they model reality, and not a penny more. I've yet to run into one that could adequately model the behavior of simple projectiles in air, much less an EM drive.
I am not sure anyone was looking at this as a high fidelity simulation but a basic proof of concept. Still the null tests were all null and interestingly the fustrum was the best of the asymmetric shape for the level of resolution and fidelity, etc. of the simulation. (I still have a sweet spot in my heart for the trombone shape.)
In any case, there is enough here to raise a flag for anyone planning to do null tests with a fustrum and a heater. There may be other effects beside ballooning going on that may need to be accounted for.
We reconsider the recently proposed nonlinear QED effect of quantum reflection of photons off an inhomogeneous strong-field region. We present new results for strong fields varying both in space and time. While such configurations can give rise to new effects such as frequency mixing, estimated reflection rates based on previous one-dimensional studies are corroborated. On a conceptual level, we critically re-examine the validity regime of the conventional locally-constant-field approximation and identify kinematic configurations which can be treated reliably. Our results further underline the discovery potential of quantum reflection as a new signature of the nonlinearity of the quantum vacuum.
I thought an evanescent effect in the borders of the frustrum materials was one of the proposed mechanisms for the thrust in the earlier threads. If so wouldn't that be a situation in which one might expect cherenkov radiation from boundary layer electrical effects? Don't evanescent waves in a solid conductor like the frustrum material have electrical secondary effects? Since the evanescent effect itself may be FTL then it would seem to me that since the speed of light varies from that of vacuum in a solid then there is an opportunities for electrons to be moving FTL (for the solid medium.)
water is a conductor. i see blue glow stuff in water around reactor rods. why?
Have not followed this subtopic close enough to understand what other effects besides thermal might be occurring.Quote rom @flybyThere is a distinct difference between an animation and a simulation:Absolutely right. The focus of these applications is to provide the appearance of real materials, not to simulate them on every level. Depending on the strength of the program, simple properties like density can be well represented, but even properties that affect physical transformation — say, something like ductility — may be poor to nonexistent.
An animation is designed with a certain intend. Their dynamics module is not designed for physical accuracy, but for efficiency and speed, consequently, these processes are hugely simplified.
From the outside they do appear to be simulations, but in reality , they're not...
There's just enough in the best animation systems to fool you into believing they model reality, and not a penny more. I've yet to run into one that could adequately model the behavior of simple projectiles in air, much less an EM drive.
I am not sure anyone was looking at this as a high fidelity simulation but a basic proof of concept. Still the null tests were all null and interestingly the fustrum was the best of the asymmetric shape for the level of resolution and fidelity, etc. of the simulation. (I still have a sweet spot in my heart for the trombone shape.)
In any case, there is enough here to raise a flag for anyone planning to do null tests with a fustrum and a heater. There may be other effects beside ballooning going on that may need to be accounted for.
water is a conductor. i see blue glow stuff in water around reactor rods. why?From what I know that is cherenkov radiation bleeding off energy of high energy particles so they travel at speeds lower than the speed of light in water or whatever medium the reaction is taking place in.
@rfmwguy did you ever witness any ionized air glow inside your see through frustum?No, but I noticed the BeO ceramic on the mag radome glowing. I also noted an "air" of metallic-like feel around it. Some commented it may be ionized copper.
But I'm looking for Cherenkov radiation from superluminal evanescent photons. Of course, being photons, they might not radiate other photons.
I can understand this type of radiation for particles with restmass traveling faster than light in a medium like "hot" neutrons in water.
You're realy looking for photons who emit photons ??? ?
Neutrons and photons do not produce Cherenkov radiation. Charged particles such as electrons produce Cherenkov radiation when move they through a medium at a speed higher than the speed of light in that medium.
We're not going to see that in an EM drive.
@rfmwguy did you ever witness any ionized air glow inside your see through frustum?No, but I noticed the BeO ceramic on the mag radome glowing. I also noted an "air" of metallic-like feel around it. Some commented it may be ionized copper.
Not really sure on that one. Temp stabilized at abt 175 C, so it could be normal. Static tests I did had frustum shielded by copper and could not see it directly. Will video it next flight test. Am assembling DAQ and LDS display into an old PC today, waiting for replacement display, hopefully this week. Also got connectors for VNA testing on frustum. Next couple of weeks will be busy.@rfmwguy did you ever witness any ionized air glow inside your see through frustum?No, but I noticed the BeO ceramic on the mag radome glowing. I also noted an "air" of metallic-like feel around it. Some commented it may be ionized copper.
Why do you think the beryllium oxide was so glowing hot? A LOT of reflected power?
Huh, so apparently there is an initial transient of reflected power until the cavity is filled. Good to know. Starts at slide 37Why that? What do you think how many oscillations does it take to "fill" the cavity?
http://uspas.fnal.gov/materials/08UCSC/mml06_resonant_cavities_1.pdf
That's not good for users of magnetrons featuring a duty cycle.
.....
The ionized air glow I'm looking for isn't related to this Cherenkov radiation. Just looking for evidence of charged particles to move around with the Lorentz force. When I apply the right hand rule (or left) to an imaginary charged particle under TE012, I get a trajectory that resembles a torus. I'm interested in TE012 because Eagleworks reported that it was the best performing mode in the Anomalous thrust production...paper, but they didn't do further tests! Shawyer also has reported that TE012 and TE013 are the best performing modes. I'm frustumrated at the lack of hard data to support the efficacy of these modes.
.....
Over the last several days I have generated a sequence of longer and longer runs using the Yang-Shell 6 degree model. csv files for all runs, png files for the longest run and a data description file are uploaded here.What do you have changed? That pic is what we are looking for the TE01 mode :)
https://drive.google.com/folderview?id=0B1XizxEfB23tRm41bVFtM1pVYlU&usp=sharing (https://drive.google.com/folderview?id=0B1XizxEfB23tRm41bVFtM1pVYlU&usp=sharing)
Fourteen runs were made for seven run lengths, 32, 64, 128 ... 2048 cycles of the drive frequency with the antenna located alternatively at the big and small end of the frustum.
The png view files show some interesting characteristics that we haven't seen before, likely due to the runs approaching steady state, although with the high Q calculated for this model, a 2048 cycle run is far short of stead state.
One thing that I observed while making/correcting errors in location of the end cuts is the extensive amount of RF energy that meep calculates for outside of the frustum. The frustum is modelled as a solid metal (copper model) truncated cone centered in the computational lattice, then another solid air frustum centered in the computational lattice with diameters and height 1/2 inch smaller. That leaves 1/4 inch of copper model surrounding the air filled cavity and meep seems to think that there is RF energy escaping through the walls. At meep resolution = 250, the 1/4 inch copper is over 5 pixels thick. It is interesting to note that classic Maxwell allows RF energy to propagate over five grid steps into the copper.
Over the last several days I have generated a sequence of longer and longer runs using the Yang-Shell 6 degree model. csv files for all runs, png files for the longest run and a data description file are uploaded here.What do you have changed? That pic is what we are looking for the TE01 mode :)
https://drive.google.com/folderview?id=0B1XizxEfB23tRm41bVFtM1pVYlU&usp=sharing (https://drive.google.com/folderview?id=0B1XizxEfB23tRm41bVFtM1pVYlU&usp=sharing)
Fourteen runs were made for seven run lengths, 32, 64, 128 ... 2048 cycles of the drive frequency with the antenna located alternatively at the big and small end of the frustum.
The png view files show some interesting characteristics that we haven't seen before, likely due to the runs approaching steady state, although with the high Q calculated for this model, a 2048 cycle run is far short of stead state.
One thing that I observed while making/correcting errors in location of the end cuts is the extensive amount of RF energy that meep calculates for outside of the frustum. The frustum is modelled as a solid metal (copper model) truncated cone centered in the computational lattice, then another solid air frustum centered in the computational lattice with diameters and height 1/2 inch smaller. That leaves 1/4 inch of copper model surrounding the air filled cavity and meep seems to think that there is RF energy escaping through the walls. At meep resolution = 250, the 1/4 inch copper is over 5 pixels thick. It is interesting to note that classic Maxwell allows RF energy to propagate over five grid steps into the copper.
...
All the SC EMDrive stuff produced by RS since the Flight Thruster, uses Rf injection in the middle of the frustum side wall, which would inject the Rf into the middle lode of the 3 lobes of the TE013 mode. Also means at that injection point, it is the same / equal guide wavelength to/from both end plates.
I suspect doing it this way would reduce phase distortion from the Rf injection, on the already resonant standing wave, and increase the effective antenna coupling factor, lifting the loaded / operational Q value toward the max unloaded Q value.
...
Over the last several days I have generated a sequence of longer and longer runs using the Yang-Shell 6 degree model. csv files for all runs, png files for the longest run and a data description file are uploaded here.Ok... this just peaked my interest in several ways.
https://drive.google.com/folderview?id=0B1XizxEfB23tRm41bVFtM1pVYlU&usp=sharing (https://drive.google.com/folderview?id=0B1XizxEfB23tRm41bVFtM1pVYlU&usp=sharing)
Fourteen runs were made for seven run lengths, 32, 64, 128 ... 2048 cycles of the drive frequency with the antenna located alternatively at the big and small end of the frustum.
The png view files show some interesting characteristics that we haven't seen before, likely due to the runs approaching steady state, although with the high Q calculated for this model, a 2048 cycle run is far short of stead state.
One thing that I observed while making/correcting errors in location of the end cuts is the extensive amount of RF energy that meep calculates for outside of the frustum. The frustum is modelled as a solid metal (copper model) truncated cone centered in the computational lattice, then another solid air frustum centered in the computational lattice with diameters and height 1/2 inch smaller. That leaves 1/4 inch of copper model surrounding the air filled cavity and meep seems to think that there is RF energy escaping through the walls. At meep resolution = 250, the 1/4 inch copper is over 5 pixels thick. It is interesting to note that classic Maxwell allows RF energy to propagate over five grid steps into the copper.
I'm not sure what I'm seeing, more artifacts?
aero, does meep calculate past the skin depth or is it limited to the surface effects?
Shell
I know... been looking at some.I'm not sure what I'm seeing, more artifacts?
aero, does meep calculate past the skin depth or is it limited to the surface effects?
Shell
As far as I know, meep calculates wherever Maxwell's equations takes it. The medium changes from air to copper but the equations do not. Dr. Rodal might be able to give a more complete answer.
Keep looking, there are some other, even more interesting views.
This set. That's just weird.
Do these "seepage anomalies" persist in higher resolution runs?
Do these "seepage anomalies" persist in higher resolution runs?How much time would it take to increase the resolution. I know it increases exponentially with rez, but how much time is that, is it doable?
Just above. Run time increases with resolution as 23 for 3 dimensional models. That is linearly with the number of pixels in the 3-D grid. And it seems, linearly with # of cycles simulated. I could make a 32 cycle run at resolution 500, but I wouldn't want to start any higher than that.Do these "seepage anomalies" persist in higher resolution runs?How much time would it take to increase the resolution. I know it increases exponentially with rez, but how much time is that, is it doable?
Shell
Could our other "assistant" help in the time and memory needed by running it?Just above. Run time increases with resolution as 23 for 3 dimensional models. That is linearly with the number of pixels in the 3-D grid. And it seems, linearly with # of cycles simulated. I could make a 32 cycle run at resolution 500, but I wouldn't want to start any higher than that.Do these "seepage anomalies" persist in higher resolution runs?How much time would it take to increase the resolution. I know it increases exponentially with rez, but how much time is that, is it doable?
Shell
http://forum.nasaspaceflight.com/index.php?topic=38203.msg1428139#msg1428139 (http://forum.nasaspaceflight.com/index.php?topic=38203.msg1428139#msg1428139)
Could our other "assistant" help in the time and memory needed by running it?Just above. Run time increases with resolution as 23 for 3 dimensional models. That is linearly with the number of pixels in the 3-D grid. And it seems, linearly with # of cycles simulated. I could make a 32 cycle run at resolution 500, but I wouldn't want to start any higher than that.Do these "seepage anomalies" persist in higher resolution runs?How much time would it take to increase the resolution. I know it increases exponentially with rez, but how much time is that, is it doable?
Shell
http://forum.nasaspaceflight.com/index.php?topic=38203.msg1428139#msg1428139 (http://forum.nasaspaceflight.com/index.php?topic=38203.msg1428139#msg1428139)
Shell
B-CALM
B-CALM is another FDTD simulation which employs CUDA for superfast computing on the graphical card. It communicates via a HDF5 file.
Comparing the features with MEEP, based on the website:
+ very fast GPU computation
- using CUDA, depends on Nvidia cards
- smaller user base
Both BE and SE
TE012?
It sounds like you really need a version of MEEP compiled for CUDA to run on NVIDIA graphics processors in your computers.
Sort of like this guy did years ago without MEEP http://m.gpucomputing.net/sites/default/files/papers/258/gpu_3dfd_rev.pdf (http://m.gpucomputing.net/sites/default/files/papers/258/gpu_3dfd_rev.pdf)
CUDA info here: http://www.nvidia.com/object/cuda_home_new.html (http://www.nvidia.com/object/cuda_home_new.html)
The only reference I saw, while searching (Google), to MEEP and CUDA was one of the MEEP developers saying he wasn't interested in such a port.
There appears to be another MEEP like program B-Calm that does use CUDA. http://f.dominec.eu/meep/ (http://f.dominec.eu/meep/)
(from the webpage):QuoteB-CALM
B-CALM is another FDTD simulation which employs CUDA for superfast computing on the graphical card. It communicates via a HDF5 file.
Comparing the features with MEEP, based on the website:
+ very fast GPU computation
- using CUDA, depends on Nvidia cards
- smaller user base
Huh, so apparently there is an initial transient of reflected power until the cavity is filled. Good to know. Starts at slide 37Why that? What do you think how many oscillations does it take to "fill" the cavity?
http://uspas.fnal.gov/materials/08UCSC/mml06_resonant_cavities_1.pdf
That's not good for users of magnetrons featuring a duty cycle.
More than the 20 million during a single ON period(1/120 s) or much less? (half cycle at 60 Hz net frequency)
Why that? What do you think how many oscillations does it take to "fill" the cavity?
More than the 20 million during a single ON period(1/120 s) or much less? (half cycle at 60 Hz net frequency)
Thanks for the pdf-link!
.....
The ionized air glow I'm looking for isn't related to this Cherenkov radiation. Just looking for evidence of charged particles to move around with the Lorentz force. When I apply the right hand rule (or left) to an imaginary charged particle under TE012, I get a trajectory that resembles a torus. I'm interested in TE012 because Eagleworks reported that it was the best performing mode in the Anomalous thrust production...paper, but they didn't do further tests! Shawyer also has reported that TE012 and TE013 are the best performing modes. I'm frustumrated at the lack of hard data to support the efficacy of these modes.
.....
Very interesting and thought provoking post! However, I have to ask the question why anyone would expect anything but ions inside a non vacuum EM drive? I have been assuming that all gases would automatically be ionized in that environment. Am I missing something here? Thanks!
https://en.m.wikipedia.org/wiki/Ion_source#Microwave_induced_plasma
...
All the SC EMDrive stuff produced by RS since the Flight Thruster, uses Rf injection in the middle of the frustum side wall, which would inject the Rf into the middle lode of the 3 lobes of the TE013 mode. Also means at that injection point, it is the same / equal guide wavelength to/from both end plates.
I suspect doing it this way would reduce phase distortion from the Rf injection, on the already resonant standing wave, and increase the effective antenna coupling factor, lifting the loaded / operational Q value toward the max unloaded Q value.
...
I'm unclear about the advantage of a TE013 over a TE011. Wouldn't a TE011 also have equal guide wavelengths to/from both end plates?
Would increasing the effective antenna coupling factor also increase the quality when using a waveguide delivery which is already critically coupled to the frustum? Yang indicated that a TE011 resulted in the highest quality in her simulations, and she used a waveguide delivery.
Would increasing the Q factor be worth separating the maximum E field strength into three lobes?
I guess this last question ultimately boils down to what Mulletron is getting at: we still don't know what causes thrust so we can't really say which mode is better for 'thrust production'. Some modes might have the potential for higher quality or easier coupling etc...
What if the secret sauce is having one lobe spanning the maximum height of the frustum?
Perhaps it has to do with two counter rotating lobes?
Maybe having many counter rotating lobes would be ideal?
------------------------------------------------------------------------------------------------------------------------------
How could a dielectric 'mimic' the output of a magnetron?
The fact that EW couldn't get thrust with a TE012 mode without the dielectric means we should blame the source.
I think the secret to thrust lies in figuring out how a dielectric + amp = (a less efficient) magnetron
OR
Could their TE012 mode actually be a different mode? According to the paper, their TE012 was at 1.88 GHz but on the comsol plots they have TE012 at 2.18 GHz. Did the latter dimensions come after the experiment?
If they actually didn't excite a TE mode, the need for a dielectric could be completely due to the mode.
Could our other "assistant" help in the time and memory needed by running it?Just above. Run time increases with resolution as 23 for 3 dimensional models. That is linearly with the number of pixels in the 3-D grid. And it seems, linearly with # of cycles simulated. I could make a 32 cycle run at resolution 500, but I wouldn't want to start any higher than that.Do these "seepage anomalies" persist in higher resolution runs?How much time would it take to increase the resolution. I know it increases exponentially with rez, but how much time is that, is it doable?
Shell
http://forum.nasaspaceflight.com/index.php?topic=38203.msg1428139#msg1428139 (http://forum.nasaspaceflight.com/index.php?topic=38203.msg1428139#msg1428139)
Shell
Aachen EmDrive update. Just in case you missed it. Click the headline for YouTube video.Really like these guys going to the interferometer. My hunch is that low power and high freq will need very fine measurement resolution. They'll need Shell's International Emdrive Flight Test Facility with her vertical supports buried in tons of concrete 8)
There is some music also. Check your volume first. Safety first ;D
https://www.reddit.com/r/EmDrive/comments/3lpfpd/hackaday_emdrive_interferometer_tests_interesting/
I watched a couple times and I'm still not sure what I'm seeing, I wish he would have had a VO (no not a drink) to explain what he was doing and what the tests were trying to show.Aachen EmDrive update. Just in case you missed it. Click the headline for YouTube video.Really like these guys going to the interferometer. My hunch is that low power and high freq will need very fine measurement resolution. They'll need Shell's International Emdrive Flight Test Facility with her vertical supports buried in tons of concrete 8)
There is some music also. Check your volume first. Safety first ;D
https://www.reddit.com/r/EmDrive/comments/3lpfpd/hackaday_emdrive_interferometer_tests_interesting/
SE and BE looks like TE01, the gif's show the Hz component.Both BE and SE
TE012?
Don't know. That one really looks to me to be numeric in nature. If it is then higher resolution would just smooth it out.
That is, if you are addressing the jagged edges around the top of the gif. If you are asking a question about the mode, then pardon me. Someone else will need to answer that.
You probably thought of this, but if you weigh down the scale to the center of its range, you'll be able to see +/- changes. Have a feeling you might need to start off with no weight as the lift might take it over/under-range. Look forward to pics!I watched a couple times and I'm still not sure what I'm seeing, I wish he would have had a VO (no not a drink) to explain what he was doing and what the tests were trying to show.Aachen EmDrive update. Just in case you missed it. Click the headline for YouTube video.Really like these guys going to the interferometer. My hunch is that low power and high freq will need very fine measurement resolution. They'll need Shell's International Emdrive Flight Test Facility with her vertical supports buried in tons of concrete 8)
There is some music also. Check your volume first. Safety first ;D
https://www.reddit.com/r/EmDrive/comments/3lpfpd/hackaday_emdrive_interferometer_tests_interesting/
The're heading down the right track with the test bed layout, I like it.
I'll take some pictures today after I get back from town in what I ended up with the balance beam and digital scales. I'm using the digital scales and adjusting them up and down to work with the moving fulcrum beam to be able to get a profile and cross check the accuracy of the system.
You're sharp rfmwguy!You probably thought of this, but if you weigh down the scale to the center of its range, you'll be able to see +/- changes. Have a feeling you might need to start off with no weight as the lift might take it over/under-range. Look forward to pics!I watched a couple times and I'm still not sure what I'm seeing, I wish he would have had a VO (no not a drink) to explain what he was doing and what the tests were trying to show.Aachen EmDrive update. Just in case you missed it. Click the headline for YouTube video.Really like these guys going to the interferometer. My hunch is that low power and high freq will need very fine measurement resolution. They'll need Shell's International Emdrive Flight Test Facility with her vertical supports buried in tons of concrete 8)
There is some music also. Check your volume first. Safety first ;D
https://www.reddit.com/r/EmDrive/comments/3lpfpd/hackaday_emdrive_interferometer_tests_interesting/
The're heading down the right track with the test bed layout, I like it.
I'll take some pictures today after I get back from town in what I ended up with the balance beam and digital scales. I'm using the digital scales and adjusting them up and down to work with the moving fulcrum beam to be able to get a profile and cross check the accuracy of the system.
Huh, so apparently there is an initial transient of reflected power until the cavity is filled. Good to know. Starts at slide 37
http://uspas.fnal.gov/materials/08UCSC/mml06_resonant_cavities_1.pdf
That's not good for users of magnetrons featuring a duty cycle.
Craig, I've seen mention on the net of a company that makes up to 2kw, 2.45ghz amplifiers. If you don't already have the magnetron, perhaps a powerful amp coupled with a computer control system designed to keep the signal in tune might be better. Less overall power, and probably less power on the resonant frequency, but I'm not sure how much less power. Also you could nudge the power up so you don't suddenly find out that the thing wants to move sideways as well as up/down.
Plan is to rent an existing transmitter setup and go 100kW continuous/ (50us-pulsed+) and 1MW 10us pulsed in the ~950MHz L-Band range. Magnetron setup looks very similar to the attached unit c/w transformer, waveguide launcher/isolator, etc. Hope to be able to talk more soon and show some pictures of the unit itself. Aiming for some data above background.
My personal hope is that RS/EM-Drive is better at hitting the concept with a hammer to have gotten results showing a phenomena and that Eagleworks/Q-Thruster are better theorists that we really are dealing with magneohydrodynamics and COM with the quantum vacuum that with some juice @ mode we'll get some real thrust. If not, well, at least won't be "will it, won't it" forever.Craig, I've seen mention on the net of a company that makes up to 2kw, 2.45ghz amplifiers. If you don't already have the magnetron, perhaps a powerful amp coupled with a computer control system designed to keep the signal in tune might be better. Less overall power, and probably less power on the resonant frequency, but I'm not sure how much less power. Also you could nudge the power up so you don't suddenly find out that the thing wants to move sideways as well as up/down.
Plan is to rent an existing transmitter setup and go 100kW continuous/ (50us-pulsed+) and 1MW 10us pulsed in the ~950MHz L-Band range. Magnetron setup looks very similar to the attached unit c/w transformer, waveguide launcher/isolator, etc. Hope to be able to talk more soon and show some pictures of the unit itself. Aiming for some data above background.Whoa...best of luck. Congrats on taking the plunge fellow builder!
My personal hope is that RS/EM-Drive is better at hitting the concept with a hammer to have gotten results showing a phenomena and that Eagleworks/Q-Thruster are better theorists that we really are dealing with magneohydrodynamics and COM with the quantum vacuum that with some juice @ mode we'll get some real thrust. If not, well, at least won't be "will it, won't it" forever.Craig, I've seen mention on the net of a company that makes up to 2kw, 2.45ghz amplifiers. If you don't already have the magnetron, perhaps a powerful amp coupled with a computer control system designed to keep the signal in tune might be better. Less overall power, and probably less power on the resonant frequency, but I'm not sure how much less power. Also you could nudge the power up so you don't suddenly find out that the thing wants to move sideways as well as up/down.
geeez... 100kW continuous.... you're planning on melting some copper? :pHere's the way I look at this. If he has resonance and Q at 915 Mhz and he fires this puppy up to 100 kW, this should go a long way into proving or disproving this whole thing. Not sure how to send in 100kW with flexible cable or waveguide to where frustum movement can be detected. Look forward to the config details.
You might have some serious thermal issues with that kind of power injection...
Keep in mind that Shawyer blew several magnetrons...
what if you blow that rented magnetron?
geeez... 100kW continuous.... you're planning on melting some copper? :p
You might have some serious thermal issues with that kind of power injection...
Keep in mind that Shawyer blew several magnetrons...
what if you blow that rented magnetron?
SE and BE looks like TE01, the gif's show the Hz component.Both BE and SE
TE012?
Don't know. That one really looks to me to be numeric in nature. If it is then higher resolution would just smooth it out.
That is, if you are addressing the jagged edges around the top of the gif. If you are asking a question about the mode, then pardon me. Someone else will need to answer that.
@Shell: If my memory is correct the cavity was designed for TE013
That's what the view from the side at the cone looks like also.
But i understand the confusing, its the last pic in this series that make me think there is another mode in the game too.
Spent some time today putting LDS display and DAQ module into an ancient PC. Its fast enough to datalog and also provide power to sensors. Hey, check out the cool floppy drive!
geeez... 100kW continuous.... you're planning on melting some copper? :pyet another use for microwaves:
You might have some serious thermal issues with that kind of power injection...
Keep in mind that Shawyer blew several magnetrons...
what if you blow that rented magnetron?
"Photons that travel in free space slower than the speed of light"
http://arxiv.org/pdf/1411.3987.pdf
There are differences between plane waves and Bessel beams for the propagation constant...
Finally in free space too, really interesting i think.
"Photons that travel in free space slower than the speed of light"
http://arxiv.org/pdf/1411.3987.pdf
There are differences between plane waves and Bessel beams for the propagation constant...
Finally in free space too, really interesting i think.
Very interesting paper. I have been wading through the math (its been many decades LOL) but it looks like it may be of significance to the folks here. I hope someone with better/more current math takes a look at it.
Herman
geeez... 100kW continuous.... you're planning on melting some copper? :pyet another use for microwaves:
You might have some serious thermal issues with that kind of power injection...
Keep in mind that Shawyer blew several magnetrons...
what if you blow that rented magnetron?
http://www.microwavegoldkiln.com/
Just got in, sorry been out all day.
It was mode TE012 and yes it looks like TE01 and maybe another.
ShellSE and BE looks like TE01, the gif's show the Hz component.Both BE and SE
TE012?
Don't know. That one really looks to me to be numeric in nature. If it is then higher resolution would just smooth it out.
That is, if you are addressing the jagged edges around the top of the gif. If you are asking a question about the mode, then pardon me. Someone else will need to answer that.
@Shell: If my memory is correct the cavity was designed for TE013
That's what the view from the side at the cone looks like also.
But i understand the confusing, its the last pic in this series that make me think there is another mode in the game too.
http://s1039.photobucket.com/user/shells2bells2002/library/CE%20Electromagnetic%20Reaction%20ThrusterI am jealous ;^)
Current build.
The other copper sheet for the CE frustum is out for water jet cutting, dropped it off yesterday. Should have it by the end of this week or first of next.
Shell
http://s1039.photobucket.com/user/shells2bells2002/library/CE%20Electromagnetic%20Reaction%20ThrusterI am jealous ;^)
Current build.
The other copper sheet for the CE frustum is out for water jet cutting, dropped it off yesterday. Should have it by the end of this week or first of next.
Shell
Guys, have you seen this?
https://hackaday.io/project/5596/log/25759-got-something
Looks like Paul's got something.
Guys, have you seen this?
https://hackaday.io/project/5596/log/25759-got-something
Looks like Paul's got something.
Guys, have you seen this?
https://hackaday.io/project/5596/log/25759-got-something
Looks like Paul's got something.
I'm not sure what exactly I'm looking at. What is the baseline for this? What orientation is the frustum in and is upward lift represented as the line moving up or down (for that matter what do the lines on that chart represent). If he's showing me a report of actual downward movement, well that's interesting.
Guys, have you seen this?
https://hackaday.io/project/5596/log/25759-got-something
Looks like Paul's got something.
I'm not sure what exactly I'm looking at. What is the baseline for this? What orientation is the frustum in and is upward lift represented as the line moving up or down (for that matter what do the lines on that chart represent). If he's showing me a report of actual downward movement, well that's interesting.
Maybe these are good results, but we definitely need some more context. I would like to see some duration of baseline without any power to see if there is an inherent drift. What is the interferometer measuring and what are the units?
Is he still using the levitating magnetic table and changing the speed of rotation?
I don't recall anyone saying that thrust maximizes slightly above the calculated resonant frequency (but I could definitely be wrong). Could this be due to slight thermal expansion?
by the way: build is looking great Shell! have you tried the power inverter on the magnetron? if so, do you know what effect it had?
Yesterday aero re-ran the Yang Shell 6 degree frustum and we saw some artifacts that got me wondering if they were on the inside or outside. The image is of the large plate comparing 2 different modes but same size in meep. I drew a line across the two to see if if could give me a clue if the unusual artifact was in the copper boundary walls.
You're quite right Maxwell's equations don't. What we are seeing on the picture on the left is inside of the frustum, maybe evanescent waves at the corners around the outside, or it simply could be an artifact.Yesterday aero re-ran the Yang Shell 6 degree frustum and we saw some artifacts that got me wondering if they were on the inside or outside. The image is of the large plate comparing 2 different modes but same size in meep. I drew a line across the two to see if if could give me a clue if the unusual artifact was in the copper boundary walls.
Please correct me if I'm wrong, but I don't remember Maxwell's equations accounting for tunneling...
What other mechanism could lead the program to calculate a non-zero field outside of the frustum?
You're quite right Maxwell's equations don't. What we are seeing on the picture on the left is inside of the frustum, maybe evanescent waves at the corners around the outside, or it simply could be an artifact.Yesterday aero re-ran the Yang Shell 6 degree frustum and we saw some artifacts that got me wondering if they were on the inside or outside. The image is of the large plate comparing 2 different modes but same size in meep. I drew a line across the two to see if if could give me a clue if the unusual artifact was in the copper boundary walls.
Please correct me if I'm wrong, but I don't remember Maxwell's equations accounting for tunneling...
What other mechanism could lead the program to calculate a non-zero field outside of the frustum?
Any thoughts?
Kurt
The bottom line is this is your build and what you decide given your resources is what you should do. All I can do is tell you why I went the direction I did and maybe it will help in your decision.You're quite right Maxwell's equations don't. What we are seeing on the picture on the left is inside of the frustum, maybe evanescent waves at the corners around the outside, or it simply could be an artifact.Yesterday aero re-ran the Yang Shell 6 degree frustum and we saw some artifacts that got me wondering if they were on the inside or outside. The image is of the large plate comparing 2 different modes but same size in meep. I drew a line across the two to see if if could give me a clue if the unusual artifact was in the copper boundary walls.
Please correct me if I'm wrong, but I don't remember Maxwell's equations accounting for tunneling...
What other mechanism could lead the program to calculate a non-zero field outside of the frustum?
My guess is artifact.
I haven't seen anything like it in EMPro, but I'll keep an eye out.
I'm having second thoughts about switching to an amplifier, maybe you all can help me make a decision.
It seems the biggest benefit of using an amplifier system would be difficulty. It is just a matter of borrowing a signal generator and buying the parts: isolator, coax, and a waveguide to coax, and vacuum chamber feed thru. Then we manufacture a frustum either by bending our sheet metal or sand casting and using a CNC to clean it up. Weld an adapter to the frustum and fit an aperture on it, and presto.
The con is the expected result. Linearly extending NASA's TE012 test (their highest efficiency), we would expect ~4 mN at 200 W. This is barely in our detectable threshold, although our resolution should get better in the vacuum chamber. How much better I'm not sure... We could rent a 500 W amp for a month, but there's the added complication of a required dielectric which might have greater losses at higher power. Someone mentioned that a solid state amp could be rapidly switch on/off to mimic a duty cycle, but what about the phase/amplitude modulation? I'd say best case scenario we achieve a thrust to power equal to NASA.
On the other hand, a magnetron system would be higher power, and would remove the need for a dielectric. We buy a better magnetron with more stability and maybe higher power, a circulator, 2 waveguides to coax , a matched load, and a vac chamber feed thru.
I think the biggest problem is a tunable mechanism. Maybe we could buy a short circuit plunger and attach that to one side of the frustum? I haven't simulated it yet but might be worth a shot.
The expected results would be 100-700 mN, well within our resolution and much more definitive evidence.
Option A: Simpler, more controllable, low expected thrust.
Option B: More complicated, less controllable, high expected thrust, more questions to answer.
But now school is in the way, and I'm set on graduating this year. Maybe we could make this happen by June, or maybe this experiment should be saved as a master's thesis. We've got a month to finish our proposal, and free time is dwindling...
Any thoughts?
Kurt
Guys, have you seen this?Apparently there is no dielectric inside the cavity.
https://hackaday.io/project/5596/log/25759-got-something
Looks like Paul's got something.
Guys, have you seen this?
https://hackaday.io/project/5596/log/25759-got-something
Looks like Paul's got something.
If I recall correctly, these results sound consistent with Shawyer's comments regarding EM drive thrust peaking when the frequency is slightly above a cavity's calculated resonance values.
Yesterday aero re-ran the Yang Shell 6 degree frustum and we saw some artifacts that got me wondering if they were on the inside or outside. The image is of the large plate comparing 2 different modes but same size in meep. I drew a line across the two to see if if could give me a clue if the unusual artifact was in the copper boundary walls.
Please correct me if I'm wrong, but I don't remember Maxwell's equations accounting for tunneling...
What other mechanism could lead the program to calculate a non-zero field outside of the frustum?
I'm not yet prepared to shoot it out of the air, but as it currently stands, as ignorant outsider, i don't see anything...
Maybe it needs more post-processing to make it more readable?
I suppose there is no need to warn about "voluntarism", where people are seeing things because they so badly want it to happen?
I'm going to do everything I can to design the test in ambient air. I know its not the best, but for DIY types, vac chambers, especially large ones, are a no go. Working on a plan to negate lift but only running the tests at a preheated temp. Whether thats a heater underneath or fire the magnetron up for warm-up has not been decided.
Regardless, my goal is to beat the lift characteristics which I think can be quantified and removed from the test data. Thats my hope anyway...
I'm going to do everything I can to design the test in ambient air. I know its not the best, but for DIY types, vac chambers, especially large ones, are a no go. Working on a plan to negate lift but only running the tests at a preheated temp. Whether thats a heater underneath or fire the magnetron up for warm-up has not been decided.
Regardless, my goal is to beat the lift characteristics which I think can be quantified and removed from the test data. Thats my hope anyway...
Yesterday aero re-ran the Yang Shell 6 degree frustum and we saw some artifacts that got me wondering if they were on the inside or outside. The image is of the large plate comparing 2 different modes but same size in meep. I drew a line across the two to see if if could give me a clue if the unusual artifact was in the copper boundary walls.
I'm going to do everything I can to design the test in ambient air. I know its not the best, but for DIY types, vac chambers, especially large ones, are a no go. Working on a plan to negate lift but only running the tests at a preheated temp. Whether thats a heater underneath or fire the magnetron up for warm-up has not been decided.
Regardless, my goal is to beat the lift characteristics which I think can be quantified and removed from the test data. Thats my hope anyway...
Was thinking of the mini-EMDrive that might fit into a small vacuum chamber (though I wonder if the electronics involved can run in vacuum). The forces there are small enough that they're using a laser interferometer to measure it.
For NSF-1701, I think the strange behavior of the lift might be related to air escaping from around the magnetron heatsink at random intervals. That said, I keep going back to that quantum reflection of photons paper. There were some mentions of redshift (not surprising, bouncing around photons should produce redshift). I wonder if I'm misunderstanding and some redshift is the result of the quantum mirror "powering up" and starting to reflect photons before resonance is reached. That would explain why peak thrust is reached at a frequency slightly higher than the resonant frequency of the frustum -- the waves are being redshifted down into the resonant frequency.
... At worst you'll end up with more data to help characterize the thermal lift.
I see what your saying on the RS pumps and fans but his were not strategically placed and he didn't quantify them. Even placing a air flow over the top, the maggie will still create a thermal pressure high and low that will draw the frustum upwards.I'm going to do everything I can to design the test in ambient air. I know its not the best, but for DIY types, vac chambers, especially large ones, are a no go. Working on a plan to negate lift but only running the tests at a preheated temp. Whether thats a heater underneath or fire the magnetron up for warm-up has not been decided.
Regardless, my goal is to beat the lift characteristics which I think can be quantified and removed from the test data. Thats my hope anyway...
Was thinking of the mini-EMDrive that might fit into a small vacuum chamber (though I wonder if the electronics involved can run in vacuum). The forces there are small enough that they're using a laser interferometer to measure it.
For NSF-1701, I think the strange behavior of the lift might be related to air escaping from around the magnetron heatsink at random intervals. That said, I keep going back to that quantum reflection of photons paper. There were some mentions of redshift (not surprising, bouncing around photons should produce redshift). I wonder if I'm misunderstanding and some redshift is the result of the quantum mirror "powering up" and starting to reflect photons before resonance is reached. That would explain why peak thrust is reached at a frequency slightly higher than the resonant frequency of the frustum -- the waves are being redshifted down into the resonant frequency.
... At worst you'll end up with more data to help characterize the thermal lift.
Thats my hope. When I report the thermal "settling" time after power off, think people will be surprised at the persistence. It was late last night. Had no idea it would go in for minutes. This probably tells me heating below the magnetron has stopped after power-off and the persistence is from the mag shedding heat very slowly. Not to mention lift continued upwards after power-off. However, I can't claim this to be a fact yet, its just unexpected.
As far as fans are concerned Shell, I'm gonna try and avoid any shawyer-like pumps and fans, although I might try and blow air across it perpendicular to rise. ;)
Rfmwguy -Thanks, very good thoughts. You are right, I did the 30% for 5 minute testing and it brought the mag up to temp and maintained it around 170 deg C. The beam actually starts rising fairly quickly. This surprised me since I have a 4x4 inch, 3 inch deep oil pool for the dampener.
If thermal effects operated on a timescale much longer than thrust effects, you could proceed as follows.
Cycle the magnetron on/off quite quickly, but for a long time. If the cycle time is much shorter than the response time for thermal effects, you should reach a situation where the system is always close to constant thermal effect, but with a superimposed cyclical thrust. It would be easy to pick out the corresponding cyclical component in the response. If that cyclical signal reverses when you invert the frustrum, you would have some evidence for thrust.
One fly in the ointment might be that the response time for the beam is too long to allow the rapid magnetron cycling to be seen. The method would only work if the cycle time and beam and thermal response times all fit right. At the very least you would have to pick the cycle time judiciously, and then get a little lucky with the thermal inertia.
No originality from me here, this is more or less what you did on your first test, though the cycling then was more to do with thermal management than creating a signal to extract.
R.
I'm going to do everything I can to design the test in ambient air. I know its not the best, but for DIY types, vac chambers, especially large ones, are a no go. Working on a plan to negate lift but only running the tests at a preheated temp. Whether thats a heater underneath or fire the magnetron up for warm-up has not been decided.
Regardless, my goal is to beat the lift characteristics which I think can be quantified and removed from the test data. Thats my hope anyway...
Unless Aero has changed something recently, all the MEEP simulations have air or vacuum inside and outside the copper walls. Radiation could be seen propagating outside the frustum if there were any.
Thanks! Yep, Berrylium Oxide ceramic is nasty stuff...not drilling or fiddling about with it.I'm going to do everything I can to design the test in ambient air. I know its not the best, but for DIY types, vac chambers, especially large ones, are a no go. Working on a plan to negate lift but only running the tests at a preheated temp. Whether thats a heater underneath or fire the magnetron up for warm-up has not been decided.
Regardless, my goal is to beat the lift characteristics which I think can be quantified and removed from the test data. Thats my hope anyway...
Congratulations on the continued characterization work!
Perhaps another optimization to consider is what modifications to the magnetron housing might improve passive heat dissipation? Various Intel CPU heatsinks and such have been mentioned in the past; I wonder if affixing some thermal grease and some extra heatsink fins (copper preferably, rather than aluminum) would help heat dissipation?
Pictures of your magnetron seem to suggest ?aluminum? heat sink fins.... compared to the aggressive copper fin counts available in modern CPU and chipset heatsinks, I suspect there's some low-hanging fruit available. Also seems like that magnetron was designed to be mounted with those straight heatsink fins oriented vertically (perhaps to allow a chimney effect to improve passive cooling?). I suspect the magnetron heatsink fins won't be nearly as effective when oriented horizontally and stacked on top of each other.
https://www.youtube.com/watch?v=QFPTQMX8R0I (https://www.youtube.com/watch?v=QFPTQMX8R0I)
P.S. Caution regarding potential hazardous substances within the magnetron/housing should probably be restated for the benefit of lurkers. Drilling holes into a magnetron is *NOT* recommended; the resulting air-born powders can be very dangerous. Instead, I was envisioning use of thermal grease and securing with cable clamps/ties and/or some high-temp RTV in the corners.
EDIT: fixed NSF-1701 youtube video link
EDIT: +Caution against drilling into a magnetron
Thanks! Yep, Berrylium Oxide ceramic is nasty stuff...not drilling or fiddling about with it.
Good observation. I did notice the fins (yokes) were aligned vertically in the microwave box just as you suspected. This would make a better chimney for sure, but not possible with my config.
Areo and I got the dual opposing waveguides working, wasn't sure what we would see but I hoped for a symmetrical mode generation and there was. Taking a slices of time through the CE frustum it is apparent that there are at least 2 modes overlaying each other.
I guess I can say now that after more than a year in planning, building and testing, I've proven to myself that there is something to this and we need to continue to pursue it. I consider the test positive with a force against thermal lift of approximately 18 mg average. Not every mag fire up gave that reading since often it simply held back lift, but I believe this is a good approximation. This should help others scale their test setups to be able to measure this small amount of force against a much stronger thermal lift. Preheat and go for it :)
Do I calculate that correctly, 18 mg ~ 176 micro-Newtons?
It looked like force to me, but that is a pretty small number compared even to the EW and Tajmar results.
But it looks like force, so from here we are miles ahead of where we were yesterday.
Congratulations rfmwguy, job well done and just getting started!
I guess I can say now that after more than a year in planning, building and testing, I've proven to myself that there is something to this and we need to continue to pursue it. I consider the test positive with a force against thermal lift of approximately 18 mg average. Not every mag fire up gave that reading since often it simply held back lift, but I believe this is a good approximation. This should help others scale their test setups to be able to measure this small amount of force against a much stronger thermal lift. Preheat and go for it :)
I guess I can say now that after more than a year in planning, building and testing, I've proven to myself that there is something to this and we need to continue to pursue it. I consider the test positive with a force against thermal lift of approximately 18 mg average. Not every mag fire up gave that reading since often it simply held back lift, but I believe this is a good approximation. This should help others scale their test setups to be able to measure this small amount of force against a much stronger thermal lift. Preheat and go for it :)
Thanks Mr T. I have to thank you as well, for it was you and Doc that suggested I build the dielectric-less frustum at 10.2 inches height. This was good insight. A dielectric in the frustum would "compress" the height to the original 9 inches. Without it, it expanded height just as predicted. Appreciate it.I guess I can say now that after more than a year in planning, building and testing, I've proven to myself that there is something to this and we need to continue to pursue it. I consider the test positive with a force against thermal lift of approximately 18 mg average. Not every mag fire up gave that reading since often it simply held back lift, but I believe this is a good approximation. This should help others scale their test setups to be able to measure this small amount of force against a much stronger thermal lift. Preheat and go for it :)
Congratulations on your good work.
Elimination of thermal lift is, as you have so clearly shown, of high importance, to improve the signal to noise ratio of the Force generation signal.
Makes the EW atmo measured EMDrive Force signatures highly significant, where they also had thermal issues to deal with.
I'm sure Iulian will enjoy seeing your data as his data is comparable. Attached is the scale force I observed from his upward Force video. It is clear there is thermal lift but it is also clear as the power is switch off, how quickly his Force dropped, which you also observed.
Thanks Teitur. Very observant on the messy floor. I blame my old 1973 Olds for the drips ;) Which BTW, I just got back from the shop with a rebuilt engine, so hopefully no more leaks...I guess I can say now that after more than a year in planning, building and testing, I've proven to myself that there is something to this and we need to continue to pursue it. I consider the test positive with a force against thermal lift of approximately 18 mg average. Not every mag fire up gave that reading since often it simply held back lift, but I believe this is a good approximation. This should help others scale their test setups to be able to measure this small amount of force against a much stronger thermal lift. Preheat and go for it :)
Congratulations !
This setup is very impressive and to a guy with problems refilling cleaning liquid in the car it would seem almost impossible to build something this complex in your own garage.
I agree that the video indicates thrust, but to paraphrase Churchill - this is not the end, this is not even the beginning of the end. I would say it is not even the end of the beginning. Now the real testing can start.
For a start I would like much longer runs of the device and if possible to make the magnetron active for a longer time. It is imperative to collect as much good data as possible in this configuration.
Later of course it would be very interesting to try to vary parameters in the setup to try to find out what makes this thing tick.
Thanks a lot for your incredible good work and for giving us the opportunity to share in the experience.
Teitur
Great job rfmwguy. The data looks really promising.I found this hum difference unusual as well, for the microwave controller has no way to control voltage other than on/off. My suspicion is the frustum is going through some sort of resonance cycle on its own. If someone were to be able to lock this in, I think the results would be spectacular.
I have noticed that microwave ovens (at least the older types - my current non-inverter model does not) make two kinds of humming sound while operating. You can hear it hum when it first comes on, but then moments later there is a deeper, more resonant hum, when subjectively, the contents of the microwave are more strongly affected. The reason I am pointing this out is because the thrust effect seems to be more noticeable on your graph during the louder hum stage.
Looking at your final 30% power cycle run for 3 minutes, I timed the different stages using a stopwatch and averaged them to give these durations:
Magnetron on (low hum): 6.25s
Magnetron on (louder hum): 4.44s
Magnetron off: 14.22s
The sum of these figures gives the total cycle time for 30% of 24.91s.
What is perplexing is that 30% of the cycle time is 24.91 * 0.3 = 7.47s, which suggests that that should be the total magnetron on time for each cycle, but as we can see the magnetron sounds like it is active for 6.25 + 4.44 = 10.69s, which is 43% of the total cycle time. Does this suggest that there is a difference in the effective heating ability of the microwave between the low hum and louder hum stages and the microwave's own timings account for this? Perhaps running the test again at 170oC, but with a greater or maximum power setting would show a larger effect?
Thanks Teitur. Very observant on the messy floor. I blame my old 1973 Olds for the drips ;) Which BTW, I just got back from the shop with a rebuilt engine, so hopefully no more leaks...
rfmwcarguy it has a nice ring to it. My own 65 Pontiac Grand Prix.Thanks Teitur. Very observant on the messy floor. I blame my old 1973 Olds for the drips ;) Which BTW, I just got back from the shop with a rebuilt engine, so hopefully no more leaks...I guess I can say now that after more than a year in planning, building and testing, I've proven to myself that there is something to this and we need to continue to pursue it.
Thanks a lot for your incredible good work and for giving us the opportunity to share in the experience.
Teitur
Great job rfmwguy. The data looks really promising.I found this hum difference unusual as well, for the microwave controller has no way to control voltage other than on/off. My suspicion is the frustum is going through some sort of resonance cycle on its own. If someone were to be able to lock this in, I think the results would be spectacular.
I have noticed that microwave ovens (at least the older types - my current non-inverter model does not) make two kinds of humming sound while operating. You can hear it hum when it first comes on, but then moments later there is a deeper, more resonant hum, when subjectively, the contents of the microwave are more strongly affected. The reason I am pointing this out is because the thrust effect seems to be more noticeable on your graph during the louder hum stage.
Looking at your final 30% power cycle run for 3 minutes, I timed the different stages using a stopwatch and averaged them to give these durations:
Magnetron on (low hum): 6.25s
Magnetron on (louder hum): 4.44s
Magnetron off: 14.22s
The sum of these figures gives the total cycle time for 30% of 24.91s.
What is perplexing is that 30% of the cycle time is 24.91 * 0.3 = 7.47s, which suggests that that should be the total magnetron on time for each cycle, but as we can see the magnetron sounds like it is active for 6.25 + 4.44 = 10.69s, which is 43% of the total cycle time. Does this suggest that there is a difference in the effective heating ability of the microwave between the low hum and louder hum stages and the microwave's own timings account for this? Perhaps running the test again at 170oC, but with a greater or maximum power setting would show a larger effect?
Thanks Herman...I wanted to keep the raw, "dirty" RF sprayed into the frustum just for this reason. I didn't build the frustum with the precision of a known, single frequency resonance. With a little luck, the instability of the messy RF I think passed through a resonance which probably shifted as the thing heated up anyway.Great job rfmwguy. The data looks really promising.I found this hum difference unusual as well, for the microwave controller has no way to control voltage other than on/off. My suspicion is the frustum is going through some sort of resonance cycle on its own. If someone were to be able to lock this in, I think the results would be spectacular.
I have noticed that microwave ovens (at least the older types - my current non-inverter model does not) make two kinds of humming sound while operating. You can hear it hum when it first comes on, but then moments later there is a deeper, more resonant hum, when subjectively, the contents of the microwave are more strongly affected. The reason I am pointing this out is because the thrust effect seems to be more noticeable on your graph during the louder hum stage.
Looking at your final 30% power cycle run for 3 minutes, I timed the different stages using a stopwatch and averaged them to give these durations:
Magnetron on (low hum): 6.25s
Magnetron on (louder hum): 4.44s
Magnetron off: 14.22s
The sum of these figures gives the total cycle time for 30% of 24.91s.
What is perplexing is that 30% of the cycle time is 24.91 * 0.3 = 7.47s, which suggests that that should be the total magnetron on time for each cycle, but as we can see the magnetron sounds like it is active for 6.25 + 4.44 = 10.69s, which is 43% of the total cycle time. Does this suggest that there is a difference in the effective heating ability of the microwave between the low hum and louder hum stages and the microwave's own timings account for this? Perhaps running the test again at 170oC, but with a greater or maximum power setting would show a larger effect?
First - mega cudos rfmwguy - this is outstanding. And shows once again that science is based on approach, intellectual honesty, attitude and diligence rather than megabuck budget.
My first thought on the noise change when I read LeftField's post - good ear BTW - my old ones didn't detect that :) was also some sort of resonance effect delta . We have had much discussion on cyclic/non-steady state effects inside the frustum but this would be something very interesting as it is at a much longer time scale than the simulations have looked at. Six seconds and four seconds are an eternity for most effects at Ghz ranges. This is going to take some good old fashion noodling.
Again - congrats!!!!!!
Herman
It will be a bit until I can fully test rfmwguy, but it would help tremendously if you could profile your frustum with a VNA. It will be a bit until I can test and I'm offering to loan my VMA and software along with the Spectrum analyzer. I can have it to you by this Monday. Use it for a week then send it back.Tell you what Shell, I am willing to mail you the frustum with a wifi antenna in place of the the radome and terminated with SMA female. I need a break from all the build and testing. Besides, we might as well get NSF-1701 over to our new International Filght Test Facility for possible further testing and formal display ;D
It's very important and you're a fellow Crazy Eddie DYIer. PM me!
A job very well done rfmwguy. Listening to the sound I can hear the associated magnetron lock after a second or so and then see the defection of the beam, I believe you're right on the edge of a mode lock and maybe you are using one of the lower power sub-harmonics of the magnetron to do it.
Shell
PM me with your address and I'll mail it out to you in a couple of days. Don't lose it, I might want it back sometime ;)If this effect is legit, that frustum will one day be in a museum.
Thanks Herman...I wanted to keep the raw, "dirty" RF sprayed into the frustum just for this reason. I didn't build the frustum with the precision of a known, single frequency resonance. With a little luck, the instability of the messy RF I think passed through a resonance which probably shifted as the thing heated up anyway.
The wide signal (40 MHz) probably helped me overcome mechanical imperfections. 8)
Yes, maybe we should call it Shell's International Emdrive Flight Test Facility and Museum ::)PM me with your address and I'll mail it out to you in a couple of days. Don't lose it, I might want it back sometime ;)If this effect is legit, that frustum will one day be in a museum.
You know, I'll be glad to take some time to test it out if you want me to and I'll send it back when I'm done. Expect a PM with my email and address.It will be a bit until I can fully test rfmwguy, but it would help tremendously if you could profile your frustum with a VNA. It will be a bit until I can test and I'm offering to loan my VMA and software along with the Spectrum analyzer. I can have it to you by this Monday. Use it for a week then send it back.Tell you what Shell, I am willing to mail you the frustum with a wifi antenna in place of the the radome and terminated with SMA female. I need a break from all the build and testing. Besides, we might as well get NSF-1701 over to our new International Filght Test Facility for possible further testing and formal display ;D
It's very important and you're a fellow Crazy Eddie DYIer. PM me!
A job very well done rfmwguy. Listening to the sound I can hear the associated magnetron lock after a second or so and then see the defection of the beam, I believe you're right on the edge of a mode lock and maybe you are using one of the lower power sub-harmonics of the magnetron to do it.
Shell
PM me with your address and I'll mail it out to you in a couple of days. Don't lose it, I might want it back sometime ;)
ACK! Please, I haven't even had a hot tub this morning. :oYes, maybe we should call it Shell's International Emdrive Flight Test Facility and Museum ::)PM me with your address and I'll mail it out to you in a couple of days. Don't lose it, I might want it back sometime ;)If this effect is legit, that frustum will one day be in a museum.
Thanks Herman...I wanted to keep the raw, "dirty" RF sprayed into the frustum just for this reason. I didn't build the frustum with the precision of a known, single frequency resonance. With a little luck, the instability of the messy RF I think passed through a resonance which probably shifted as the thing heated up anyway.
The wide signal (40 MHz) probably helped me overcome mechanical imperfections. 8)
Based on information that has been shared with me, what I saw in your Force generation profiles suggests your frustum may be operation on the side slope of a resonant mode that sometimes fills and resonates the cavity and sometime not. As I understand this operational characteristic, being spot on centre resonance delivers high reliability resonant locks and the further you operate down the slope, away from peak resonance, the more unreliable the resonant lock becomes.
Here´s how the chart works:
- On the left side is the camera image of the interference pattern. The grey graph is a continous sampling of the yellow line in the interference image, so if the pattern moves up, the grey graph also moves up.
- The green graph is just the pixel brightness sum within the thick green line in the interference image. It will generate a more or less sinusoidal wave over time when the pattern is moving continously. However, it will not tell you the direction in which the interference patern is moving, but it might be helpful to make small changes more visible.
- After having adjusted the mirror to get a good interference pattern, it´s not clear in which direction the pattern will move in respect to the force.
I use a magnet to determine that. My reference will be "U" if the rings of the pattern go up and "D" if they go down while attracting the platform with the magnet.
You're thinking along the same lines I am. If someone hits on a way to "lock in" to this effect, my mere 18 mg of force will likely triple, at least.Thanks Herman...I wanted to keep the raw, "dirty" RF sprayed into the frustum just for this reason. I didn't build the frustum with the precision of a known, single frequency resonance. With a little luck, the instability of the messy RF I think passed through a resonance which probably shifted as the thing heated up anyway.
The wide signal (40 MHz) probably helped me overcome mechanical imperfections. 8)
Based on information that has been shared with me, what I saw in your Force generation profiles suggests your frustum may be operation on the side slope of a resonant mode that sometimes fills and resonates the cavity and sometime not. As I understand this operational characteristic, being spot on centre resonance delivers high reliability resonant locks and the further you operate down the slope, away from peak resonance, the more unreliable the resonant lock becomes.
I love the collaborative nature of this forum - heck the whole "internets" thing ;)
As I was taking care of some chores this AM I was just thinking about this very concept. I think we have (at least) three "curves" intersecting here.
First - the wide band (40 Mhz) Maggie output peak likely slides up and down and interacts with the resonance curve of the frustum.
Second - the frustum resonance curve may also be changing with temperature. I was thinking about the mesh and heating from the power being cycled up and down. I think it may be experiencing some non-linear expansion and contraction with heat up and cool down. I know the frustum isn't any where near the temp of the Maggie, BUT it likely wouldn't take much. IIRC several pages (maybe several dozen) there was some general discussion that the geometry of the frustum varying a very small amount (IIRC less than a mm) then that could significantly affect resonance. The wire mesh has less thermal mass so any change would likely be more noticeable. I have no idea how this would affect resonance curves.
Third - the interaction of the above factors will affect the VSWR/return loss and thus the feedback of power to the Maggie. When in turn will affect the magnetrons output. One more interacting factor.
My experience when you have multi-dimensional interactions like this is the time frame for "peaks and valleys" of interaction can appear completely out of scale with other time constants of the system.
Herman
You're thinking along the same lines I am. If someone hits on a way to "lock in" to this effect, my mere 18 mg of force will likely triple, at least.Thanks Herman...I wanted to keep the raw, "dirty" RF sprayed into the frustum just for this reason. I didn't build the frustum with the precision of a known, single frequency resonance. With a little luck, the instability of the messy RF I think passed through a resonance which probably shifted as the thing heated up anyway.
The wide signal (40 MHz) probably helped me overcome mechanical imperfections. 8)
Based on information that has been shared with me, what I saw in your Force generation profiles suggests your frustum may be operation on the side slope of a resonant mode that sometimes fills and resonates the cavity and sometime not. As I understand this operational characteristic, being spot on centre resonance delivers high reliability resonant locks and the further you operate down the slope, away from peak resonance, the more unreliable the resonant lock becomes.
I love the collaborative nature of this forum - heck the whole "internets" thing ;)
As I was taking care of some chores this AM I was just thinking about this very concept. I think we have (at least) three "curves" intersecting here.
First - the wide band (40 Mhz) Maggie output peak likely slides up and down and interacts with the resonance curve of the frustum.
Second - the frustum resonance curve may also be changing with temperature. I was thinking about the mesh and heating from the power being cycled up and down. I think it may be experiencing some non-linear expansion and contraction with heat up and cool down. I know the frustum isn't any where near the temp of the Maggie, BUT it likely wouldn't take much. IIRC several pages (maybe several dozen) there was some general discussion that the geometry of the frustum varying a very small amount (IIRC less than a mm) then that could significantly affect resonance. The wire mesh has less thermal mass so any change would likely be more noticeable. I have no idea how this would affect resonance curves.
Third - the interaction of the above factors will affect the VSWR/return loss and thus the feedback of power to the Maggie. When in turn will affect the magnetrons output. One more interacting factor.
My experience when you have multi-dimensional interactions like this is the time frame for "peaks and valleys" of interaction can appear completely out of scale with other time constants of the system.
Herman
Already, we're smacking down a theoretical photon drive by most accounts.
You're thinking along the same lines I am. If someone hits on a way to "lock in" to this effect, my mere 18 mg of force will likely triple, at least.
Already, we're smacking down a theoretical photon drive by most accounts.
It will be a bit until I can fully test rfmwguy, but it would help tremendously if you could profile your frustum with a VNA. It will be a bit until I can test and I'm offering to loan my VMA and software along with the Spectrum analyzer. I can have it to you by this Monday. Use it for a week then send it back.Tell you what Shell, I am willing to mail you the frustum with a wifi antenna in place of the the radome and terminated with SMA female. I need a break from all the build and testing. Besides, we might as well get NSF-1701 over to our new International Filght Test Facility for possible further testing and formal display ;D
It's very important and you're a fellow Crazy Eddie DYIer. PM me!
A job very well done rfmwguy. Listening to the sound I can hear the associated magnetron lock after a second or so and then see the defection of the beam, I believe you're right on the edge of a mode lock and maybe you are using one of the lower power sub-harmonics of the magnetron to do it.
Shell
PM me with your address and I'll mail it out to you in a couple of days. Don't lose it, I might want it back sometime ;)
Great idea! Since I'm sending the frustum to Shell, would you be willing to loan her your SMA to Radome converter so she can make a VNA sweep? This would be much better than the wifi antenna I planned to mount in the frustum...pending her approval, of course.It will be a bit until I can fully test rfmwguy, but it would help tremendously if you could profile your frustum with a VNA. It will be a bit until I can test and I'm offering to loan my VMA and software along with the Spectrum analyzer. I can have it to you by this Monday. Use it for a week then send it back.Tell you what Shell, I am willing to mail you the frustum with a wifi antenna in place of the the radome and terminated with SMA female. I need a break from all the build and testing. Besides, we might as well get NSF-1701 over to our new International Filght Test Facility for possible further testing and formal display ;D
It's very important and you're a fellow Crazy Eddie DYIer. PM me!
A job very well done rfmwguy. Listening to the sound I can hear the associated magnetron lock after a second or so and then see the defection of the beam, I believe you're right on the edge of a mode lock and maybe you are using one of the lower power sub-harmonics of the magnetron to do it.
Shell
PM me with your address and I'll mail it out to you in a couple of days. Don't lose it, I might want it back sometime ;)
Congrats rfmwguy! You're an inspiration to all of us.
As far as the VNA is concerned, I would recommend either buying a professionally made SMA to magnetron antenna or making your own. I don't know how close the magnetron is to a wifi antenna, you are probably more knowledgable on the subject.
The antenna adapter we made seemed to work well: we had significant deflection at a point determined to be resonance and a cm away we saw zero deflection where it shouldn't have resonated. Although this deflection might have been caused by an asymmetric flow of current, the resonant position must have had orders of magnitude higher surface currents.
Making the adapter is simple, buy an identical magnetron, take it apart and carefully cut through the center where the tap wire attaches to the spokes, and solder an SMA panel mount to it.
Making the adapter is simple, buy an identical magnetron, take it apart and carefully cut through the center where the tap wire attaches to the spokes, and solder an SMA panel mount to it.
Great idea! Since I'm sending the frustum to Shell, would you be willing to loan her your SMA to Radome converter so she can make a VNA sweep? This would be much better than the wifi antenna I planned to mount in the frustum...pending her approval, of course.It will be a bit until I can fully test rfmwguy, but it would help tremendously if you could profile your frustum with a VNA. It will be a bit until I can test and I'm offering to loan my VMA and software along with the Spectrum analyzer. I can have it to you by this Monday. Use it for a week then send it back.Tell you what Shell, I am willing to mail you the frustum with a wifi antenna in place of the the radome and terminated with SMA female. I need a break from all the build and testing. Besides, we might as well get NSF-1701 over to our new International Filght Test Facility for possible further testing and formal display ;D
It's very important and you're a fellow Crazy Eddie DYIer. PM me!
A job very well done rfmwguy. Listening to the sound I can hear the associated magnetron lock after a second or so and then see the defection of the beam, I believe you're right on the edge of a mode lock and maybe you are using one of the lower power sub-harmonics of the magnetron to do it.
Shell
PM me with your address and I'll mail it out to you in a couple of days. Don't lose it, I might want it back sometime ;)
Congrats rfmwguy! You're an inspiration to all of us.
As far as the VNA is concerned, I would recommend either buying a professionally made SMA to magnetron antenna or making your own. I don't know how close the magnetron is to a wifi antenna, you are probably more knowledgable on the subject.
The antenna adapter we made seemed to work well: we had significant deflection at a point determined to be resonance and a cm away we saw zero deflection where it shouldn't have resonated. Although this deflection might have been caused by an asymmetric flow of current, the resonant position must have had orders of magnitude higher surface currents.
Making the adapter is simple, buy an identical magnetron, take it apart and carefully cut through the center where the tap wire attaches to the spokes, and solder an SMA panel mount to it.
I have a very dead maggie I'll use and it'a a great idea plus I will have a good magnet too boot.
Shell
Out for a bit, going to see what my water jet guys did or didn't.
I guess I can say now that after more than a year in planning, building and testing, I've proven to myself that there is something to this and we need to continue to pursue it. I consider the test positive with a force against thermal lift of approximately 18 mg average. Not every mag fire up gave that reading since often it simply held back lift, but I believe this is a good approximation. This should help others scale their test setups to be able to measure this small amount of force against a much stronger thermal lift. Preheat and go for it :)I think it'd be enlightening to see the voltage from the laser measured in much smaller time intervals, maybe a couple times a second, even 60hz or more if we can get it. I think I see your point about the thrust fighting the thermal lift but the actual events are fairly short and only comprise a few samples. I don't know where this is going next but that's my two cents. The oscillations and turbulence caused by the thermal currents seem to be nearly as great as the possible thrust, more resolution would, I think, give a much clearer picture and more detail may show other interesting behaviors currently invisible.
I agree. This test was all about setting the stage the best I could for myself and allowing others to take what I have learned and go from there.I guess I can say now that after more than a year in planning, building and testing, I've proven to myself that there is something to this and we need to continue to pursue it. I consider the test positive with a force against thermal lift of approximately 18 mg average. Not every mag fire up gave that reading since often it simply held back lift, but I believe this is a good approximation. This should help others scale their test setups to be able to measure this small amount of force against a much stronger thermal lift. Preheat and go for it :)I think it'd be enlightening to see the voltage from the laser measured in much smaller time intervals, maybe a couple times a second, even 60hz or more if we can get it. I think I see your point about the thrust fighting the thermal lift but the actual events are fairly short and only comprise a few samples. I don't know where this is going next but that's my two cents. The oscillations and turbulence caused by the thermal currents seem to be nearly as great as the possible thrust, more resolution would, I think, give a much clearer picture and more detail may show other interesting behaviors currently invisible.
I agree. This test was all about setting the stage the best I could for myself and allowing others to take what I have learned and go from there.
Reddit user True-Creek did a supurb job of tone-decoding magnetron hum (on) and matching it against a trace. Note pauses to lift, lift resume and downward deflection in the blue area (mag on) and white area (mag off). Some traces in the blue area looks like it was trying to form, but could not.Very very interesting. Particularly the 9/12 cases of lift shortly after power off (if I am understanding this graphic). To me this looks very much like what I would expect to see with a wild freq. source and variable degree of resonance. In particular, the delayed effect could be coming from residual energy at a "correct" frequency still in system after the overall drive with others in the spectrum removed. Thinking as I type so this probably isn't clear but that graph was very exciting.
Here are several data points to consider for yourself:
"I just ran a screenshot of the video through ImageJ and a Java-plugin that extracts the column-wise maximum. I've also extracted the the humming from the magentron (235.5-240 Hz) but it needed some correction:
https://i.imgur.com/0ioKt7B.png
It looks much more convincing than the impression I got from the video. There are about N=12 full trials and in 10/12 trials there is no obvious lift. In 9/12 trials there were lifts shortly after they ended. In only 6 or 7 there were significant drops.
Edit: Here is the data of the graph, though not normalized but in the original aspect ratio: http://pastebin.com/raw.php?i=eM5rLVXy " by true-creek on reddit/emdrive 9/25/15
Recent email corro with Roger Shawyer.
There is a lot of real engineering information and solid answers in this exchange.
The difference between the loaded and unloaded Q Roger has shared with an ideal injection match is new information and is why I believe SPR are now doing pulsed injection as after the Rf injection period is over (and the associated injection caused phase distortion) the cavity is them able to form a non phase distorted resonant condition, doubling the cavity Q (going from loaded Q to unloaded Q) and Force generation.
Roger makes this clear in his statement about the Flight Thruster and how the Force generated matches the doubled unloaded Q and not the 1/2 lower loaded, Rf injection period Q.
So as Roger explains in his latest patent application, the main Force is generated AFTER the Rf injection is switched off. Why? Because after the Rf pulse stops, the cavity Q doubles as it can now operate in an unloaded mode.
Nice breadcrumbs Roger. You have answered a lot of my questions.
Thanks.
> Hi Roger,
>
> I'm home again, recovering from the effects of the super bug I picked up in
> hospital. Have a deep wound, caused by the super bug, where one of the
> robot arms entered by abdomen. Like a 2nd belly button. Docs want me to
> take it very gentle until it starts to naturally regrow. They don't want to
> close it up just yet, just to be sure to not close with some of the
> superbug bacteria still active inside. So for now I have a patch over my
> 2nd belly button and daily nurse visits.
>
> So some time before I'm allowed in my workshop. But not wasting the time.
>
> Most of the software for the Raspberry PI 2B based control & monitoring
> system has been written. Will have a high power 5GHz WiFi based USB
> connection for control & data logging from the rotary table to my laptop.
>
> Point of discussion with others, NSF and myself. How do you / SPR measure
> frustum bandwidth / Q? Do you use bandwidth at 3dB away from max S11 rtn
> loss dB freq (as Prof Yang does) or 3dBs from 0 dB ref level as
> Eagleworks / NSF do or do you guys use another method? Would prefer to
> measure Q as you guys do. Makes a massive difference in bandwidth, Q &
> projected Force generation.
> Hi TT
>
> Using a network analyser to determine the Q of a high Q cavity via S11 is
> quick but requires a good understanding of the effect of scan speed and
> detector bandwidth or the results can be wildly inaccurate.
>
> For the delivery data of space qualified equipment, a calibrated procedure
> using separate signal source and power meter was usually specified. This is
> the technique we have always used at SPR.
>
> The signal source is put on a slow sweep to allow a dwell time of at least
> 10X time constant at each measurement point. The internal cavity power is
> measured using a cavity wall mounted detector measuring at least 30dB down
> (a very short probe!) and a wide detection bandwidth. The data is processed
> to measure the bandwidth 3dB down from max power level for at least two
> scans, one in each direction. (they must agree or there is a drift error in
> the measurement).
>
> Hope this helps.
>
> Best regards
>
> Roger
> Hi Roger,
>
> Thanks.
>
> So you prefer 2 port S21 over 1 port S11 or is S11 ok if the scan speed is
> VERY slow?
>
> I do understand the need for a SLOW scan and the frustum fill time / TC
> factor. What you shared is in line with my understanding.
>
> May I share this information on NSF cause there are a few arm chair
> "experts" that are strongly saying to measure bandwidth 3dB from the rtn
> loss 0dB reference level, which to me is madness.
> Hi TT
>
> S11 measurements are complicated if a highly tuned input circuit is used. I have seen published measurements that are clearly the Q of the input circuit only.
>
> Note that all Q measurements are Loaded Q measurements, and strictly speaking, if a perfect match is achieved, the actual unloaded Q is twice the measured Q.
>
> There are endless papers on the complications of Q measurement which is why smart customers are very careful about deliverable test data.
>
> The thrust predicted by the Thrust equation assumes unloaded Q. The measured thrust for the Flight thruster was very close to the predicted thrust when twice the measured Q was used in the equation.
>
> The design was successfully sold to Boeing on the measured thrust data.
>
> Feel free to share my comments on your forum.
>
> Best regards
>
> Roger
Knew I had just seen this. I am thinking that this is very similar to what rfmwguy et al are seeing in his last previous post. Sorry I don't know how to include multiple quotes in a reply. I think what we may be seeing is sometimes called resonance chasing/dragging or resonance capture (a little different really). I am really looking forward to Shell's results looking into this frustum.
H.
You're thinking along the same lines I am. If someone hits on a way to "lock in" to this effect, my mere 18 mg of force will likely triple, at least.Thanks Herman...I wanted to keep the raw, "dirty" RF sprayed into the frustum just for this reason. I didn't build the frustum with the precision of a known, single frequency resonance. With a little luck, the instability of the messy RF I think passed through a resonance which probably shifted as the thing heated up anyway.
The wide signal (40 MHz) probably helped me overcome mechanical imperfections. 8)
Based on information that has been shared with me, what I saw in your Force generation profiles suggests your frustum may be operation on the side slope of a resonant mode that sometimes fills and resonates the cavity and sometime not. As I understand this operational characteristic, being spot on centre resonance delivers high reliability resonant locks and the further you operate down the slope, away from peak resonance, the more unreliable the resonant lock becomes.
I love the collaborative nature of this forum - heck the whole "internets" thing ;)
As I was taking care of some chores this AM I was just thinking about this very concept. I think we have (at least) three "curves" intersecting here.
First - the wide band (40 Mhz) Maggie output peak likely slides up and down and interacts with the resonance curve of the frustum.
Second - the frustum resonance curve may also be changing with temperature. I was thinking about the mesh and heating from the power being cycled up and down. I think it may be experiencing some non-linear expansion and contraction with heat up and cool down. I know the frustum isn't any where near the temp of the Maggie, BUT it likely wouldn't take much. IIRC several pages (maybe several dozen) there was some general discussion that the geometry of the frustum varying a very small amount (IIRC less than a mm) then that could significantly affect resonance. The wire mesh has less thermal mass so any change would likely be more noticeable. I have no idea how this would affect resonance curves.
Third - the interaction of the above factors will affect the VSWR/return loss and thus the feedback of power to the Maggie. When in turn will affect the magnetrons output. One more interacting factor.
My experience when you have multi-dimensional interactions like this is the time frame for "peaks and valleys" of interaction can appear completely out of scale with other time constants of the system.
Herman
Already, we're smacking down a theoretical photon drive by most accounts.
"triple, at least" - Amen. For those out there not familiar with resonance and resonant phenomenon - tripling might be very very conservative.
H.
Areo and I got the dual opposing waveguides working, wasn't sure what we would see but I hoped for a symmetrical mode generation and there was. Taking a slices of time through the CE frustum it is apparent that there are at least 2 modes overlaying each other.
NSF-1701 Update - Flight Test 2B is now available to view.
...
https://youtu.be/HPm2oPUPi2Q
Recent email corro with Roger Shawyer.
So as Roger explains in his latest patent application, the main Force is generated AFTER the Rf injection is switched off. Why? Because after the Rf pulse stops, the cavity Q doubles as it can now operate in an unloaded mode.
> I'm home again, recovering from the effects of the super bug I picked up in
> hospital. Have a deep wound, caused by the super bug
Recent email corro with Roger Shawyer.
So as Roger explains in his latest patent application, the main Force is generated AFTER the Rf injection is switched off. Why? Because after the Rf pulse stops, the cavity Q doubles as it can now operate in an unloaded mode.
I would think, that unless he's using an RF relay or switch, the same impedance of the feed guide is still present, loading the cavity.
Several pages back concern was expressed over a changing impedance of the cavity as it "rings up". That is what a quarter-wave, or resonant matching section is for; a quarter wave (or multiple thereof) has the wonderful ability to match impedance.Quote> I'm home again, recovering from the effects of the super bug I picked up in
> hospital. Have a deep wound, caused by the super bug
Uh oh, very sorry to hear that. There is a cure:
http://edition.cnn.com/2015/03/31/health/anglo-saxon-potion-mrsa/
I take garlic often, and colloidal silver, which Nasa has now decided is OK for water filtration on the ISS.
Don't know where to find Ox-gall.
Recent email corro with Roger Shawyer.
There is a lot of real engineering information and solid answers in this exchange.
The difference between the loaded and unloaded Q Roger has shared with an ideal injection match is new information and is why I believe SPR are now doing pulsed injection as after the Rf injection period is over (and the associated injection caused phase distortion) the cavity is them able to form a non phase distorted resonant condition, doubling the cavity Q (going from loaded Q to unloaded Q) and Force generation.
Roger makes this clear in his statement about the Flight Thruster and how the Force generated matches the doubled unloaded Q and not the 1/2 lower loaded, Rf injection period Q.
So as Roger explains in his latest patent application, the main Force is generated AFTER the Rf injection is switched off. Why? Because after the Rf pulse stops, the cavity Q doubles as it can now operate in an unloaded mode.
Nice breadcrumbs Roger. You have answered a lot of my questions.
Thanks.
> Hi Roger,
>
> I'm home again, recovering from the effects of the super bug I picked up in
> hospital. Have a deep wound, caused by the super bug, where one of the
> robot arms entered by abdomen. Like a 2nd belly button. Docs want me to
> take it very gentle until it starts to naturally regrow. They don't want to
> close it up just yet, just to be sure to not close with some of the
> superbug bacteria still active inside. So for now I have a patch over my
> 2nd belly button and daily nurse visits.
>
> So some time before I'm allowed in my workshop. But not wasting the time.
>
> Most of the software for the Raspberry PI 2B based control & monitoring
> system has been written. Will have a high power 5GHz WiFi based USB
> connection for control & data logging from the rotary table to my laptop.
>
> Point of discussion with others, NSF and myself. How do you / SPR measure
> frustum bandwidth / Q? Do you use bandwidth at 3dB away from max S11 rtn
> loss dB freq (as Prof Yang does) or 3dBs from 0 dB ref level as
> Eagleworks / NSF do or do you guys use another method? Would prefer to
> measure Q as you guys do. Makes a massive difference in bandwidth, Q &
> projected Force generation.
> Hi TT
>
> Using a network analyser to determine the Q of a high Q cavity via S11 is
> quick but requires a good understanding of the effect of scan speed and
> detector bandwidth or the results can be wildly inaccurate.
>
> For the delivery data of space qualified equipment, a calibrated procedure
> using separate signal source and power meter was usually specified. This is
> the technique we have always used at SPR.
>
> The signal source is put on a slow sweep to allow a dwell time of at least
> 10X time constant at each measurement point. The internal cavity power is
> measured using a cavity wall mounted detector measuring at least 30dB down
> (a very short probe!) and a wide detection bandwidth. The data is processed
> to measure the bandwidth 3dB down from max power level for at least two
> scans, one in each direction. (they must agree or there is a drift error in
> the measurement).
>
> Hope this helps.
>
> Best regards
>
> Roger
> Hi Roger,
>
> Thanks.
>
> So you prefer 2 port S21 over 1 port S11 or is S11 ok if the scan speed is
> VERY slow?
>
> I do understand the need for a SLOW scan and the frustum fill time / TC
> factor. What you shared is in line with my understanding.
>
> May I share this information on NSF cause there are a few arm chair
> "experts" that are strongly saying to measure bandwidth 3dB from the rtn
> loss 0dB reference level, which to me is madness.
> Hi TT
>
> S11 measurements are complicated if a highly tuned input circuit is used. I have seen published measurements that are clearly the Q of the input circuit only.
>
> Note that all Q measurements are Loaded Q measurements, and strictly speaking, if a perfect match is achieved, the actual unloaded Q is twice the measured Q.
>
> There are endless papers on the complications of Q measurement which is why smart customers are very careful about deliverable test data.
>
> The thrust predicted by the Thrust equation assumes unloaded Q. The measured thrust for the Flight thruster was very close to the predicted thrust when twice the measured Q was used in the equation.
>
> The design was successfully sold to Boeing on the measured thrust data.
>
> Feel free to share my comments on your forum.
>
> Best regards
>
> Roger
Reddit user True-Creek did a supurb job of tone-decoding magnetron hum (on) and matching it against a trace. Note pauses to lift, lift resume and downward deflection in the blue area (mag on) and white area (mag off). Some traces in the blue area looks like it was trying to form, but could not.
Here are several data points to consider for yourself:
"I just ran a screenshot of the video through ImageJ and a Java-plugin that extracts the column-wise maximum. I've also extracted the the humming from the magentron (235.5-240 Hz) but it needed some correction:
https://i.imgur.com/0ioKt7B.png
It looks much more convincing than the impression I got from the video. There are about N=12 full trials and in 10/12 trials there is no obvious lift. In 9/12 trials there were lifts shortly after they ended. In only 6 or 7 there were significant drops.
Edit: Here is the data of the graph, though not normalized but in the original aspect ratio: http://pastebin.com/raw.php?i=eM5rLVXy " by true-creek on reddit/emdrive 9/25/15
Thanks. I mispoke in the video, the bias (4kV) is not 500kV but 50kV. Its the clear insulator and got it from McMaster Carr. The filament (white wire) is always hot, and the preheat refers to the mag tube and heatsink, not the filament. Good catch.NSF-1701 Update - Flight Test 2B is now available to view.
...
https://youtu.be/HPm2oPUPi2Q
Excellent work! Stable setup and great sensitivity. The video makes results very credible.
Forgive the cheap arm-chair quarterbacking-
Isn't the filament hot (at high-voltage)? what good does using a stiff 500kV cable do, when the opposite end of a low-resistance filament its connected to, is connected to a (lower-voltage) rated wire pair, 1/2 of which is at ground?
It appears obvious that the plotted air-thermal is stopped when the magnetron kicks on. However, it occurs to me, that if a chimney effect is occurring, that energy that was heating the magnetron could be being diverted to heat the frustrum, and diverting momentum from the thermal air current. Perhaps a simple test is simply inverting the frustrum.
And, as Traveler stated, would be very nice to know the tuning and Q of the cavity. From what I've read about wire mesh waveguides having 10 x the attenuation of solid, I'll be surprised if the Q is over 500. I'd swag 300.
Apologize for the cheap critique on a great job well done! Thank's a lot!
Be sure to look at the mag on data as pauses in lift (flattening of sustem oscillation), not just drop. Also, look at datapoints at mag off. Think you'll see stonger evidence in the mag off condition.Reddit user True-Creek did a supurb job of tone-decoding magnetron hum (on) and matching it against a trace. Note pauses to lift, lift resume and downward deflection in the blue area (mag on) and white area (mag off). Some traces in the blue area looks like it was trying to form, but could not.
Here are several data points to consider for yourself:
"I just ran a screenshot of the video through ImageJ and a Java-plugin that extracts the column-wise maximum. I've also extracted the the humming from the magentron (235.5-240 Hz) but it needed some correction:
https://i.imgur.com/0ioKt7B.png
It looks much more convincing than the impression I got from the video. There are about N=12 full trials and in 10/12 trials there is no obvious lift. In 9/12 trials there were lifts shortly after they ended. In only 6 or 7 there were significant drops.
Edit: Here is the data of the graph, though not normalized but in the original aspect ratio: http://pastebin.com/raw.php?i=eM5rLVXy " by true-creek on reddit/emdrive 9/25/15
data interpretation depends on your expectations sometimes.
Here's what I see on the tone matched graph and raw data.
1st magnetron on: Drop starts before power on
2nd magnetron on: Drop starts before power on
3rd magnetron on: Drop starts before power on
4th magnetron on: Drop starts before power on
5th magnetron on: No drop
6th magnetron on: No drop
7th magnetron on: Drop starts at magnetron on
8th magnetron on: No drop at magnetron on
9th magnetron on: Drop starts at magnetron on
10th magnetron on: No drop at magnetron on
11th magnetron on: No drop at magnetron on
12th magnetron on: Drop starts at magnetron on
13th magnetron on: No drop at magnetron on
Depending on how you choose your drop point, this could be construed as totally random.
A linear regression fits the data with an R squared of .71
Using that to determine the residuals, it seems to be a good fit to an oscillation in the system with a period of approximately 9 data points of True-Creek's data.
That period is very close to the on-off timing of the magnetron.
1st derivative looks pattern free. i.e. noisy.
At a minimum, I'd consider re-running with a longer on-off window. The oscillation in the system could be overriding any signal.
I would call this test inconclusive. :(
Be sure to look at the mag on data as pauses in lift (flattening of sustem oscillation), not just drop. Also, look at datapoints at mag off. Think you'll see stonger evidence in the mag off condition.Reddit user True-Creek did a supurb job of tone-decoding magnetron hum (on) and matching it against a trace. Note pauses to lift, lift resume and downward deflection in the blue area (mag on) and white area (mag off). Some traces in the blue area looks like it was trying to form, but could not.
Here are several data points to consider for yourself:
"I just ran a screenshot of the video through ImageJ and a Java-plugin that extracts the column-wise maximum. I've also extracted the the humming from the magentron (235.5-240 Hz) but it needed some correction:
https://i.imgur.com/0ioKt7B.png
It looks much more convincing than the impression I got from the video. There are about N=12 full trials and in 10/12 trials there is no obvious lift. In 9/12 trials there were lifts shortly after they ended. In only 6 or 7 there were significant drops.
Edit: Here is the data of the graph, though not normalized but in the original aspect ratio: http://pastebin.com/raw.php?i=eM5rLVXy " by true-creek on reddit/emdrive 9/25/15
data interpretation depends on your expectations sometimes.
Here's what I see on the tone matched graph and raw data.
1st magnetron on: Drop starts before power on
2nd magnetron on: Drop starts before power on
3rd magnetron on: Drop starts before power on
4th magnetron on: Drop starts before power on
5th magnetron on: No drop
6th magnetron on: No drop
7th magnetron on: Drop starts at magnetron on
8th magnetron on: No drop at magnetron on
9th magnetron on: Drop starts at magnetron on
10th magnetron on: No drop at magnetron on
11th magnetron on: No drop at magnetron on
12th magnetron on: Drop starts at magnetron on
13th magnetron on: No drop at magnetron on
Depending on how you choose your drop point, this could be construed as totally random.
A linear regression fits the data with an R squared of .71
Using that to determine the residuals, it seems to be a good fit to an oscillation in the system with a period of approximately 9 data points of True-Creek's data.
That period is very close to the on-off timing of the magnetron.
1st derivative looks pattern free. i.e. noisy.
At a minimum, I'd consider re-running with a longer on-off window. The oscillation in the system could be overriding any signal.
I would call this test inconclusive. :(
So, does that mean he does 2 port measurement, contrary to what you were asserting in the beginning of the thread? Or am I misunderstanding this?
Before you box the drive up to send to me, are you planning to do one more test with the drive inverted 180 from this test?Everything is still as it was when I ended FT 2B the other night. I'll see how things go this evening. What I might do is another test run as is and then another inverted. I know people are scrambling for data as I am scrambling for a break.
Shell
Reddit user True-Creek did a supurb job of tone-decoding magnetron hum (on) and matching it against a trace. Note pauses to lift, lift resume and downward deflection in the blue area (mag on) and white area (mag off). Some traces in the blue area looks like it was trying to form, but could not.
Here are several data points to consider for yourself:
"I just ran a screenshot of the video through ImageJ and a Java-plugin that extracts the column-wise maximum. I've also extracted the the humming from the magentron (235.5-240 Hz) but it needed some correction:
https://i.imgur.com/0ioKt7B.png
It looks much more convincing than the impression I got from the video. There are about N=12 full trials and in 10/12 trials there is no obvious lift. In 9/12 trials there were lifts shortly after they ended. In only 6 or 7 there were significant drops.
Edit: Here is the data of the graph, though not normalized but in the original aspect ratio: http://pastebin.com/raw.php?i=eM5rLVXy " by true-creek on reddit/emdrive 9/25/15
data interpretation depends on your expectations sometimes.
Here's what I see on the tone matched graph and raw data.
1st magnetron on: Drop starts before power on
2nd magnetron on: Drop starts before power on
3rd magnetron on: Drop starts before power on
4th magnetron on: Drop starts before power on
5th magnetron on: No drop
6th magnetron on: No drop
7th magnetron on: Drop starts at magnetron on
8th magnetron on: No drop at magnetron on
9th magnetron on: Drop starts at magnetron on
10th magnetron on: No drop at magnetron on
11th magnetron on: No drop at magnetron on
12th magnetron on: Drop starts at magnetron on
13th magnetron on: No drop at magnetron on
Depending on how you choose your drop point, this could be construed as totally random.
A linear regression fits the data with an R squared of .71
Using that to determine the residuals, it seems to be a good fit to an oscillation in the system with a period of approximately 9 data points of True-Creek's data.
That period is very close to the on-off timing of the magnetron.
1st derivative looks pattern free. i.e. noisy.
At a minimum, I'd consider re-running with a longer on-off window. The oscillation in the system could be overriding any signal.
I would call this test inconclusive. :(
Before you box the drive up to send to me, are you planning to do one more test with the drive inverted 180 from this test?Everything is still as it was when I ended FT 2B the other night. I'll see how things go this evening. What I might do is another test run as is and then another inverted. I know people are scrambling for data as I am scrambling for a break.
Shell
Let me see how much ambition I have tonight. Am also working on an ethernet screen capture solution to the hokey camcorder to monitor routine.
Actually, I have so many more tests I could run, this could turn into a full time endeavor...an unpaid full time endeavor if you catch my drift.
Still a work in progress VP, not quite ready to throw out here yet. Thanks.Areo and I got the dual opposing waveguides working, wasn't sure what we would see but I hoped for a symmetrical mode generation and there was. Taking a slices of time through the CE frustum it is apparent that there are at least 2 modes overlaying each other.
That's the kind of traveling wave I expected to see. Very nice! Would like to see the outline/dimensions of the cavity and feed waveguide.
Using a commercial VNA from well known companies there is NO problem with this kind of measurements. You can choose the sweep-time as well as a discrete frequency, applying averaging or what you like. However the used PLL dictate the min. possible frequency steps.So, does that mean he does 2 port measurement, contrary to what you were asserting in the beginning of the thread? Or am I misunderstanding this?
As I read it, SPR don't use a VNA for their highly accurate loaded Q measurements but use a separate freq sweeper with programmable dwell time to allow the cavity fill to happen before moving to the next freq and a separate power meter with a min 30dB attenuator, fed by a sensor in the frustum side wall.
That said, Roger did say S11 1 port scans can be used, providing the sweep can be done in discrete steps and each step stopping / dwelling long enough for the cavity to do a 10 TC long fill. Don't know if any VNA can do a dwell at each sweep freq increment.
Do too fast a stepped sweep or a continuously varied freq sweep, with either setup, and you may get rubbish / miss the resonance peaks / dips as the cavity may not be given enough time to do a 5 TC long fill.
As I understand the fill issue, the above was just confirmation that cavity fill time MUST be taken into consideration when doing a resonance search / sweep..
Main point for me was SPR measure the cavity bandwidth and loaded Q 3dB away from the max rtn loss dB point or max power point and not 3dB from the 0dB ref level.
Another biggie was SPR's Force equation uses unloaded Q.
Another was in a properly measured cavity, the measured loaded Q is 50% of the unloaded Q.
BTW this is the 1st time I know of that SPR has disclosed how they measure cavity Q. We know Prof Yang used 3db from max S11 rtn loss dB for their measured Q because it is in her papers.
I did. :(
That's why the good lord invented residuals analysis. Remove the trend and look for meaningful deviations from the trend.
In your first test, the residuals analysis clearly showed deltas associated with power on vs power off. In this data I don't see any pattern. :(
In your first test, the residuals analysis clearly showed deltas associated with power on vs power off. In this data I don't see any pattern. :(
Before you box the drive up to send to me, are you planning to do one more test with the drive inverted 180 from this test?Everything is still as it was when I ended FT 2B the other night. I'll see how things go this evening. What I might do is another test run as is and then another inverted. I know people are scrambling for data as I am scrambling for a break.
Shell
Let me see how much ambition I have tonight. Am also working on an ethernet screen capture solution to the hokey camcorder to monitor routine.
Actually, I have so many more tests I could run, this could turn into a full time endeavor...an unpaid full time endeavor if you catch my drift.
Would someone so kind to share the magnetron sound analyze data for the 729 data points (of rfmwguy's last run)in the format of 1 for on, 0 for off please?
Fits this table: http://pastebin.com/raw.php?i=eM5rLVXy
Found the problem.Well. I must be nuts. I just recorded Flight Test 2C, a full 1 hour video before I tear down the test stand. Here's what I did (before I ran out of storage on my 16G SD card:
You have 240 (actually 236 I think) data points for a 3 minute run.
rfmwguy stated that his software only captures a data point every 1.5 seconds (120 datapoints).
You have interpreted the computer extrapolating a smooth line between two points as actual data.
Conclusion: rfmwguy can you upload the raw files that you logged to NSF. We need to see the actual recorded data to figure out what is going on here.
Not nuts but a little Crazy Eddie. :DFound the problem.Well. I must be nuts.
You have 240 (actually 236 I think) data points for a 3 minute run.
rfmwguy stated that his software only captures a data point every 1.5 seconds (120 datapoints).
You have interpreted the computer extrapolating a smooth line between two points as actual data.
Conclusion: rfmwguy can you upload the raw files that you logged to NSF. We need to see the actual recorded data to figure out what is going on here.
Rendered and 30% completed on youtube upload.Not nuts but a little Crazy Eddie. :DFound the problem.Well. I must be nuts.
You have 240 (actually 236 I think) data points for a 3 minute run.
rfmwguy stated that his software only captures a data point every 1.5 seconds (120 datapoints).
You have interpreted the computer extrapolating a smooth line between two points as actual data.
Conclusion: rfmwguy can you upload the raw files that you logged to NSF. We need to see the actual recorded data to figure out what is going on here.
Thank you for doing this rfmwguy. You're a heck of a builder and one good guy. I look forward to looking at the data.
Shell
https://www.youtube.com/watch?v=zHIVeWhCMU8Rendered and 30% completed on youtube upload.Not nuts but a little Crazy Eddie. :DFound the problem.Well. I must be nuts.
You have 240 (actually 236 I think) data points for a 3 minute run.
rfmwguy stated that his software only captures a data point every 1.5 seconds (120 datapoints).
You have interpreted the computer extrapolating a smooth line between two points as actual data.
Conclusion: rfmwguy can you upload the raw files that you logged to NSF. We need to see the actual recorded data to figure out what is going on here.
Thank you for doing this rfmwguy. You're a heck of a builder and one good guy. I look forward to looking at the data.
Shell
Found the problem. You have 240 (actually 236 I think) instead of 120 data points for the 3 minute run.
Would someone so kind to share the magnetron sound analyze data for the 729 data points (of rfmwguy's last run)in the format of 1 for on, 0 for off please?
Fits this table: http://pastebin.com/raw.php?i=eM5rLVXy
I'm the one who extracted this data from the video. I wasn't quite pleased with that result, so I redid the table and the magnetron on/off data:
http://pastebin.com/raw.php?i=kv9SiT7y
(https://i.imgur.com/r3XNnCU.png)
Perhaps someone can listen to the video closely and confirm that the starting and end points of the intervals are reasonably precise.
Would someone so kind to share the magnetron sound analyze data for the 729 data points (of rfmwguy's last run)in the format of 1 for on, 0 for off please?
Fits this table: http://pastebin.com/raw.php?i=eM5rLVXy
I'm the one who extracted this data from the video. I wasn't quite pleased with that result, so I redid the table and the magnetron on/off data:
http://pastebin.com/raw.php?i=kv9SiT7y
(https://i.imgur.com/r3XNnCU.png)
Perhaps someone can listen to the video closely and confirm that the starting and end points of the intervals are reasonably precise.
Would someone so kind to share the magnetron sound analyze data for the 729 data points (of rfmwguy's last run)in the format of 1 for on, 0 for off please?
Fits this table: http://pastebin.com/raw.php?i=eM5rLVXy
I'm the one who extracted this data from the video. I wasn't quite pleased with that result, so I redid the table and the magnetron on/off data:
http://pastebin.com/raw.php?i=kv9SiT7y
Perhaps someone can listen to the video closely and confirm that the starting and end points of the intervals are reasonably precise.
glennfish: So if I am understanding correctly, this basically confirms (in a statistically rigorous way) that we are seeing anomalous thrust in the 2C flight test?
glennfish: So if I am understanding correctly, this basically confirms (in a statistically rigorous way) that we are seeing anomalous thrust in the 2C flight test?
This data was from the previous data run, not the one he did last night.
No. Not statistically rigorous by any means at this point.
Statistically, it suggests that that with one data set, there were differences in RFMWGUY's device's "lift" rates depending on whether the magnetron was on or off.
There are only a dozen or so slope measurements at this time. That's no where near enough to make a claim of statistical significance.
There needs to be a lot more data to make any claims.
What can be stated is that RFMWGUY stated that he observed a difference in lift rates depending on whether the magnatron was on or off. Statistically speaking, he wasn't hallucinating that difference during that test sequence.
Any claim beyond that at this time is a stretch.
Two questions:
1 - Is anyone recording these data analysis efforts for posterity in such a controlled way as to eliminate confusion about which data run they apply to? On the wiki?
2 - Now that you know the limitations of rfmwguy's test set-up, what kind of test run or runs would be needed in order to provide statistical significance?
I wonder if it is possible/desirable to modify the microwave controller to provide more on/off cycles per minute and if such higher cycle rate would provide more usable data or would it simply blur the data generated even more?
Great job rfmwguy. Your tests have illustrated to all concerned that the test stand set-up is probably more important than the cavity, at least it has many more fiddly-bits to deal with. The cavity does what it does, its the test stand that determines whether or not it did anything.
Found the problem. You have 240 (actually 236 I think) instead of 120 data points for the 3 minute run.
Upsampling a signal is no information loss.
Turn on takes place between data point 1 and data point 2. The computer drawsa sloping line between the two points. You sample data point 1.5 between points 1 and 2. The device has not yet been turned on. Because the computer does not know when turn on occurs it produces a line that begins to slope immediately after data point 1 and runs through point 1.5. The result is it looks like the drop began before turn on. If you simply had two points and no line you would see point, turn on, next point drop.
NSF-1701 Update - Flight Test 2D test data is attached. It is a spreadsheet with over 2700 time stamped data points. The LDS sensor voltage is on Channel 1. Unfortunately, I did not have enough time to make Channel 2 a mag on/off channel, so I will be uploading a video that displays the test stands computer (windows) clock. When you hear the hum, the mag is on, so mark it on the spreadsheet next to system time, which is synched.
There are two, 10 minutes tests at 50% power cycle that starts from cold, not preheated. Take a look at the attached spreadsheet and be ready to plug in the mag on and off markers once you view the video.
I hope this helps everyone out. I know there are some fantastic brain trusts out here that do far better with data analysis than I could. Enjoy. I'll post a link to the video soon.
Here is the video link, it is about 40% uploaded and will be viewable soon:
https://youtu.be/djhxm1Ep12I
Dave
EXCEPT...
My stat package seems to think that it doesn't have to give more that the most significant digit when it switches to exponential mode. That makes the analysis difficult (there is a way, but I was planning other things today).
Does anyone have the ability to get a half dozen digits after the decimal on a 6th order polynomial regression.
Here's what I get: y = -2E-18x^6 + 1E-14x^5 - 5E-11x^4 + 6E-08x^3 - 3E-05x^2 + 0.0032x + 6.8491
x is the row number starting with 1, blowing away the first 149 data points.
If anyone can get me the lots more digits on the first 5 coefficients, I'd be grateful. :)
Am I right that this data is going to be inverted so that movement up causes the beam to get closer to the sensor, causing the chart to move down?Yes, lift will cause the LDS voltage to drop.
That there is a slight spike immediately before several of the "buzz periods" suggests that the audible hum doesn't perfectly align with the production of energy. It may be that the audio track is slightly behind the video. It may also be that, rather than having the slab-sided waveform suggested by the audio, the actual production of energy from the magnetron involves a ramp-up, ramp-down period with the hum representing only a portion of the energized period.Very good call. I noticed that the leakage meter never went off instantly when the hum started, meaning there has to be some sort of buildup. This makes deciding when to indicate "on" might be best done with a diode detector rather than hum start. Regardless, the voltage applied gives us a general "on" condition.
EXCEPT...
My stat package seems to think that it doesn't have to give more that the most significant digit when it switches to exponential mode. That makes the analysis difficult (there is a way, but I was planning other things today).
Does anyone have the ability to get a half dozen digits after the decimal on a 6th order polynomial regression.
Here's what I get: y = -2E-18x^6 + 1E-14x^5 - 5E-11x^4 + 6E-08x^3 - 3E-05x^2 + 0.0032x + 6.8491
x is the row number starting with 1, blowing away the first 149 data points.
If anyone can get me the lots more digits on the first 5 coefficients, I'd be grateful. :)
If you are using Excel then it is possible to show more significant digits:
I assume you have the trendline equation displayed on the chart.
• select the equation (surrounding box will be highlighted)
• right-click box and select "format trendline label ..." in the pop-up menu
• select "number" in the left-hand pane
• choose "scientific" in the category column
• increase the decimal places number to whatever you want
• close pop-up box and new format will be displayed on chart
Edit: added instructions
I would like to ask the members of the forum for some input/opinions.Yay! Welcome to the DIY world! Fear not, as I took a lot of the naysayer hits when I started posting a few months ago, so in a sense I've absorbed a lot of the pressure for those who follow 8)
Some of you know me from my posts on various RF and microwave issues. I am just now starting a DIY emdrive test effort – I am finally getting my workshop back on line following a move –and I want to try to build on the outstanding work of SeeShell, rfmwguy, and others to hopefully make some small contribution of my own.
Anyway – to the request.
There are a multitude of test environment design factors of course and this is just a start but in order to begin limiting the possible test space I have narrowed down overall test configurations to the following:
1. Rotary Table configuration – unit under test (UUT) thrusting either posigrade or retrograde to rotation
2. Linear (slide) configuration – air or other low friction surface. UUT thrusting along the access of the slide.
3. Balance Beam (ala rfmwguy and seeshells) UUT thrusting either up or down
In my thinking all have things going for them as well as potential problems, but I would like to ask for your thoughts on each configurations. In particular these are the things I have been considering:
• Overall Pros and Cons
• Challenges to getting usable data output
• Potential systemic and situational error sources
• Data which should/can be measured for either signal or noise/error determinations
ANYTHING else you can think of –
Thanks in advance. If you would prefer to reply by private message rather than on the forum that is fine with me however please indicate any information which you do not want disseminated further.
Herman
PS – for those who don’t know me and to provide some credibility background - I have worked in both professionally and DIY settings on RF from LF to 40+ Ghz, high power RF and RF power supplies, vacuum chambers and systems, nuclear power plants and various and sundry other technical fields including aerospace and defense for the past 39 years. Well acquainted with safety procedures - wrote some for my last company. This will be my first big retirement project and I can’t wait to get started.
Rfmwguy -Thanks so much for your analysis. It is especially insightful as a dampening of "force" change as temp increases which likely indicates a resonance shift of the frustum or frequency shift of the magnetron. This matches exactly what shawyer, nasa and perhaps Yang had commented on. In fact, some of the designs had tunable elements that changed resonance points as temp varied.
I did a fourier series analysis of the test D data you posted, having been through the video to manually add the on/off periods of the magnetron.
The effect as in NSF1701 test 1, your initial test, persists: there is a signal correlated quite strongly with the magnetron in the first two-thirds of your first 10 minute test in test D. This is when the magnetron was cool. Later, the effect becomes much less pronounced.
I took the opportunity to analyse the cooling period when the magnetron was not running, by way of a control test. That gives us some hint as to what signals might be regarded as significant.
Though particularly the first part of the first test appears distinct, especially in the frequency domain, overall the scale of the effect is comparable to that in the control.
I think you would be hard-pushed to claim the data overall strongly supports the hypothesis of thrust. Perhaps the picture is consistent with that notion if you are losing resonance as the magnetron gets hot, but that's just a stab in the dark.
My analysis is attached. There are three charts in the first four tabs which illustrate the above conclusion.
R.
I would like to ask the members of the forum for some input/opinions.
Some of you know me from my posts on various RF and microwave issues. I am just now starting a DIY emdrive test effort – I am finally getting my workshop back on line following a move –and I want to try to build on the outstanding work of SeeShell, rfmwguy, and others to hopefully make some small contribution of my own.
Anyway – to the request.
There are a multitude of test environment design factors of course and this is just a start but in order to begin limiting the possible test space I have narrowed down overall test configurations to the following:
1. Rotary Table configuration – unit under test (UUT) thrusting either posigrade or retrograde to rotation
2. Linear (slide) configuration – air or other low friction surface. UUT thrusting along the access of the slide.
3. Balance Beam (ala rfmwguy and seeshells) UUT thrusting either up or down
In my thinking all have things going for them as well as potential problems, but I would like to ask for your thoughts on each configurations. In particular these are the things I have been considering:
• Overall Pros and Cons
• Challenges to getting usable data output
• Potential systemic and situational error sources
• Data which should/can be measured for either signal or noise/error determinations
ANYTHING else you can think of –
Thanks in advance. If you would prefer to reply by private message rather than on the forum that is fine with me however please indicate any information which you do not want disseminated further.
Herman
PS – for those who don’t know me and to provide some credibility background - I have worked in both professionally and DIY settings on RF from LF to 40+ Ghz, high power RF and RF power supplies, vacuum chambers and systems, nuclear power plants and various and sundry other technical fields including aerospace and defense for the past 39 years. Well acquainted with safety procedures - wrote some for my last company. This will be my first big retirement project and I can’t wait to get started.
I've added the magnetron data via frequency analysis (using ffmpeg, Audacity for sample rate conversion and visualization and the R packages tuneR, signal and mmand for the actual work). Everything worked fine except for a propeller plane that was humming at 240 Hz as well, so that needed some editing. :) I hope it fits the video data well. I've only checked the first and last sample.]
(https://i.imgur.com/ZvdMRbH.png)
https://i.imgur.com/ZvdMRbH.png
http://pastebin.com/raw.php?i=JPRBS1YF
Two questions:
1 - Is anyone recording these data analysis efforts for posterity in such a controlled way as to eliminate confusion about which data run they apply to? On the wiki?
2 - Now that you know the limitations of rfmwguy's test set-up, what kind of test run or runs would be needed in order to provide statistical significance?
I wonder if it is possible/desirable to modify the microwave controller to provide more on/off cycles per minute and if such higher cycle rate would provide more usable data or would it simply blur the data generated even more?
Great job rfmwguy. Your tests have illustrated to all concerned that the test stand set-up is probably more important than the cavity, at least it has many more fiddly-bits to deal with. The cavity does what it does, its the test stand that determines whether or not it did anything.
...
If I put on my methodology hat, there are so many issues in the experimental design that collectively it's amazing that there are any interesting results at all. All statistics can do is give a probability that a difference exists. It says nothing about why the difference exists. In a proper experimental design, you state your hypothesis and select your measurement and analysis method before you turn on the power. In this case, finding an interesting statistic after performing the experiment would have gotten me thrown out of gradschool.
Two questions:
1 - Is anyone recording these data analysis efforts for posterity in such a controlled way as to eliminate confusion about which data run they apply to? On the wiki?
2 - Now that you know the limitations of rfmwguy's test set-up, what kind of test run or runs would be needed in order to provide statistical significance?
I wonder if it is possible/desirable to modify the microwave controller to provide more on/off cycles per minute and if such higher cycle rate would provide more usable data or would it simply blur the data generated even more?
Great job rfmwguy. Your tests have illustrated to all concerned that the test stand set-up is probably more important than the cavity, at least it has many more fiddly-bits to deal with. The cavity does what it does, its the test stand that determines whether or not it did anything.
...
If I put on my methodology hat, there are so many issues in the experimental design that collectively it's amazing that there are any interesting results at all. All statistics can do is give a probability that a difference exists. It says nothing about why the difference exists. In a proper experimental design, you state your hypothesis and select your measurement and analysis method before you turn on the power. In this case, finding an interesting statistic after performing the experiment would have gotten me thrown out of gradschool.
Thanks...this last paragraph had a lot of stopping power with me. Since I do not have an advanced degree in science, it took me a while for this to sink in. You are 100% correct. Classical scientific research states you cannot move forward without a hypothesis first.
It does beg the question, does this rule somehow limit potential discovery? I recall having this conversation many years ago, me being on the side of "try and find out" my engineering pal being on the side of rigorous adherance to classical methodology. We never resolved our "dispute" but its good to have this refreshed in our minds.
Had I followed canon, I would never have started my build, for I have no hypothesis on why this thing might work, I only know there was enough to spark my interest in trying...perhaps the classic scientific versus why not try argument might live on forever. :o
Two questions:
1 - Is anyone recording these data analysis efforts for posterity in such a controlled way as to eliminate confusion about which data run they apply to? On the wiki?
2 - Now that you know the limitations of rfmwguy's test set-up, what kind of test run or runs would be needed in order to provide statistical significance?
I wonder if it is possible/desirable to modify the microwave controller to provide more on/off cycles per minute and if such higher cycle rate would provide more usable data or would it simply blur the data generated even more?
Great job rfmwguy. Your tests have illustrated to all concerned that the test stand set-up is probably more important than the cavity, at least it has many more fiddly-bits to deal with. The cavity does what it does, its the test stand that determines whether or not it did anything.
...
If I put on my methodology hat, there are so many issues in the experimental design that collectively it's amazing that there are any interesting results at all. All statistics can do is give a probability that a difference exists. It says nothing about why the difference exists. In a proper experimental design, you state your hypothesis and select your measurement and analysis method before you turn on the power. In this case, finding an interesting statistic after performing the experiment would have gotten me thrown out of gradschool.
Thanks...this last paragraph had a lot of stopping power with me. Since I do not have an advanced degree in science, it took me a while for this to sink in. You are 100% correct. Classical scientific research states you cannot move forward without a hypothesis first.
It does beg the question, does this rule somehow limit potential discovery? I recall having this conversation many years ago, me being on the side of "try and find out" my engineering pal being on the side of rigorous adherance to classical methodology. We never resolved our "dispute" but its good to have this refreshed in our minds.
Had I followed canon, I would never have started my build, for I have no hypothesis on why this thing might work, I only know there was enough to spark my interest in trying...perhaps the classic scientific versus why not try argument might live on forever. :o
Thanks...this last paragraph had a lot of stopping power with me. Since I do not have an advanced degree in science, it took me a while for this to sink in. You are 100% correct. Classical scientific research states you cannot move forward without a hypothesis first.
It does beg the question, does this rule somehow limit potential discovery? I recall having this conversation many years ago, me being on the side of "try and find out" my engineering pal being on the side of rigorous adherance to classical methodology. We never resolved our "dispute" but its good to have this refreshed in our minds.
Had I followed canon, I would never have started my build, for I have no hypothesis on why this thing might work, I only know there was enough to spark my interest in trying...perhaps the classic scientific versus why not try argument might live on forever. :o
Indeed - and had we waited for a comprehensive hypothesis as to why things fall to the ground, we'd still be waiting to discover gravity.
Perhaps, in the investigative stage, the experimental work is more akin to natural philosophy - observing nature and speculating about what it means that thus is so and why - as a natural preamble to more rigorous scientific analysis proving the hows and whys.
Nothing wrong with that. Experiment on.
I'll post the spreadsheet later. I have to work for a living. :(
Methodologically, that leads to MY prediction that your next run would also show different slopes and in MY world I set up analysis to test that. If you see my latest analysis, that was consistent with a proper methodology. And, to your efforts, statistically suggestive that your hunches and methods are showing a real phenomenon.
Based on the previous observation that the slope was different between mag on vs mag off times:
1. I broke the data into 47 pairs of data
- pair 1 was the power on data
- pair 2 was the power off data immediately following
2. I calculated the linear regression slope for each pair of data
3. I calculated if the on slope was greater than the off slope (in this case all the data trends were down for the observations
4. Assuming the probability of the slopes being < or > is 50/50, a simple binomial calculation shows
Number of trials: 47
Number of "successes": 27
Probability that result is random: 0.069
The data used was the most recent provided from yesterday with the mag-on/off coding provided this a.m. Sorry to confuse that.
2nd, you're right about alternative statistical tests. I had to stick to my simplest apriori assumption which was dirt simple. Are the slopes different, yes or no? :) When you wear a methodology hat, you have to stick to what you said, even if it means you have to kick yourself in the head ten times because the real data suggests something different.
Your observations and suggestions are correct. There's a slug of other things we can throw at this too many perhaps :), t test among them. I haven't had the time today for more than a rudimentary look.
re the null hypothesis, that would in this case be "The slopes are not different between power on vs power off states". The null hypothesis appears to be in jeopardy.
Thanks Wolfy, when you say First test, is it First test of Flight Test 2D yesterday?The data used was the most recent provided from yesterday with the mag-on/off coding provided this a.m. Sorry to confuse that.
2nd, you're right about alternative statistical tests. I had to stick to my simplest apriori assumption which was dirt simple. Are the slopes different, yes or no? :) When you wear a methodology hat, you have to stick to what you said, even if it means you have to kick yourself in the head ten times because the real data suggests something different.
Your observations and suggestions are correct. There's a slug of other things we can throw at this too many perhaps :), t test among them. I haven't had the time today for more than a rudimentary look.
re the null hypothesis, that would in this case be "The slopes are not different between power on vs power off states". The null hypothesis appears to be in jeopardy.
I just did the t-test to the excel sheet you added. You can see it in Sheet1 right next to the data columns, starting in cell E3. I highlighted in green the two most important stats to note, namely the one-tailed and two-tailed probabilities that the means of mag on and mag off are actually the same (ie. conform to the null hypothesis).
As you can see, the two-tailed probability is basically what you calculated using the binomial approach.
The one-tailed probability is the chance that the means are the same if we assume directionality (the mean of voltage on is less than voltage off), which is a step too far in my opinion.
At the bare minimum, we would have to see the P(T<=t) two-tail result to be less than 0.05 to call this result statistically significant (in the sense a journal would call it statistically significant). As it stands we can't conclude anything about the last test other than the slopes of mag on and mag off are so close as to be indistinguishable by statistical means.
So for the second test, no, the null hypothesis is not in jeopardy. To reiterate though, the first test did show a statistically significant difference between mag on and mag off. The spreadsheet is attached.
Thanks Wolfy, when you say First test, is it First test of Flight Test 2D yesterday?
No problemo...I'm trying to sort out if the 2 run on FT 2D showed less than the first. I believe it did, meaning the cold start was a better test condition for the frustum design. I think it may be, since the dimensions suggested probably didn't take into effect heating up of the assembly or the mag itself. A little tidbit for pondering you might say 8)Thanks Wolfy, when you say First test, is it First test of Flight Test 2D yesterday?
Sorry for the confusion, I'm not hip with the lingo :P.
What I call "first test" is actually your Flight Test #2B, the very first test you performed with your new equipment and posted on friday.
None of the above is for Flight Test #2D.
Have edited my comment. The excel file rfmwguytest1-t-test is the t-test performed on the data for NSF-1701 Flight Test #2B.
The data used was the most recent provided from yesterday with the mag-on/off coding provided this a.m. Sorry to confuse that.
2nd, you're right about alternative statistical tests. I had to stick to my simplest apriori assumption which was dirt simple. Are the slopes different, yes or no? :) When you wear a methodology hat, you have to stick to what you said, even if it means you have to kick yourself in the head ten times because the real data suggests something different.
Your observations and suggestions are correct. There's a slug of other things we can throw at this too many perhaps :), t test among them. I haven't had the time today for more than a rudimentary look.
re the null hypothesis, that would in this case be "The slopes are not different between power on vs power off states". The null hypothesis appears to be in jeopardy.
I just did the t-test to the excel sheet you added. You can see it in Sheet1 right next to the data columns, starting in cell E3. I highlighted in green the two most important stats to note, namely the one-tailed and two-tailed probabilities that the means of mag on and mag off are actually the same (ie. conform to the null hypothesis).
As you can see, the two-tailed probability is basically what you calculated using the binomial approach.
The one-tailed probability is the chance that the means are the same if we assume directionality (the mean of voltage on is less than voltage off), which is a step too far in my opinion.
At the bare minimum, we would have to see the P(T<=t) two-tail result to be less than 0.05 to call this result statistically significant (in the sense a journal would call it statistically significant). As it stands we can't conclude anything about the last test other than the slopes of mag on and mag off are so close as to be indistinguishable by statistical means.
So for the second test, no, the null hypothesis is not in jeopardy. To reiterate though, NSF-1701 Flight Test #2B did show a statistically significant difference between mag on and mag off. The spreadsheet is attached.
I'm not sure if taking the mean of a slope is meaningful. It might be more appropriate to run a t-test not on the slopes, but on the on/off data elements themselves. If you look at the raw data, the slopes are almost all negative, consistent with the thermal trending, but the rate fits a polynomial, so the meaning of the slope comparison changes depending where you are on that fit. If the thermal drift were linear, then... I'm still not convinced, but I'm open.
I may try to do a t of ts on the 47 data groups, if I can figure out what that means.
If you look at the raw data, the slopes are almost all negative, consistent with the thermal trending,but the rate fits a polynomial, so the meaning of the slope comparison changes depending where you are on that fit.
Two questions:
1 - Is anyone recording these data analysis efforts for posterity in such a controlled way as to eliminate confusion about which data run they apply to? On the wiki?
2 - Now that you know the limitations of rfmwguy's test set-up, what kind of test run or runs would be needed in order to provide statistical significance?
I wonder if it is possible/desirable to modify the microwave controller to provide more on/off cycles per minute and if such higher cycle rate would provide more usable data or would it simply blur the data generated even more?
Great job rfmwguy. Your tests have illustrated to all concerned that the test stand set-up is probably more important than the cavity, at least it has many more fiddly-bits to deal with. The cavity does what it does, its the test stand that determines whether or not it did anything.
...
If I put on my methodology hat, there are so many issues in the experimental design that collectively it's amazing that there are any interesting results at all. All statistics can do is give a probability that a difference exists. It says nothing about why the difference exists. In a proper experimental design, you state your hypothesis and select your measurement and analysis method before you turn on the power. In this case, finding an interesting statistic after performing the experiment would have gotten me thrown out of gradschool.
Thanks...this last paragraph had a lot of stopping power with me. Since I do not have an advanced degree in science, it took me a while for this to sink in. You are 100% correct. Classical scientific research states you cannot move forward without a hypothesis first.
It does beg the question, does this rule somehow limit potential discovery? I recall having this conversation many years ago, me being on the side of "try and find out" my engineering pal being on the side of rigorous adherance to classical methodology. We never resolved our "dispute" but its good to have this refreshed in our minds.
Had I followed canon, I would never have started my build, for I have no hypothesis on why this thing might work, I only know there was enough to spark my interest in trying...perhaps the classic scientific versus why not try argument might live on forever. :o
Two questions:
1 - Is anyone recording these data analysis efforts for posterity in such a controlled way as to eliminate confusion about which data run they apply to? On the wiki?
2 - Now that you know the limitations of rfmwguy's test set-up, what kind of test run or runs would be needed in order to provide statistical significance?
I wonder if it is possible/desirable to modify the microwave controller to provide more on/off cycles per minute and if such higher cycle rate would provide more usable data or would it simply blur the data generated even more?
Great job rfmwguy. Your tests have illustrated to all concerned that the test stand set-up is probably more important than the cavity, at least it has many more fiddly-bits to deal with. The cavity does what it does, its the test stand that determines whether or not it did anything.
...
If I put on my methodology hat, there are so many issues in the experimental design that collectively it's amazing that there are any interesting results at all. All statistics can do is give a probability that a difference exists. It says nothing about why the difference exists. In a proper experimental design, you state your hypothesis and select your measurement and analysis method before you turn on the power. In this case, finding an interesting statistic after performing the experiment would have gotten me thrown out of gradschool.
Thanks...this last paragraph had a lot of stopping power with me. Since I do not have an advanced degree in science, it took me a while for this to sink in. You are 100% correct. Classical scientific research states you cannot move forward without a hypothesis first.
It does beg the question, does this rule somehow limit potential discovery? I recall having this conversation many years ago, me being on the side of "try and find out" my engineering pal being on the side of rigorous adherance to classical methodology. We never resolved our "dispute" but its good to have this refreshed in our minds.
Had I followed canon, I would never have started my build, for I have no hypothesis on why this thing might work, I only know there was enough to spark my interest in trying...perhaps the classic scientific versus why not try argument might live on forever. :o
I'm not sure if taking the mean of a slope is meaningful. It might be more appropriate to run a t-test not on the slopes, but on the on/off data elements themselves. If you look at the raw data, the slopes are almost all negative, consistent with the thermal trending, but the rate fits a polynomial, so the meaning of the slope comparison changes depending where you are on that fit. If the thermal drift were linear, then... I'm still not convinced, but I'm open.
I may try to do a t of ts on the 47 data groups, if I can figure out what that means.
This is my read on the situation and justification for the t-test:
The rate of change of defection is proportional to the force on the beam. Ergo the slope of a section (a section being defined as mag on or off) is equal to the average rate of change of deflection over that section and is thus proportional to the average force on the beam over that section.
We want to know: is there a difference in the average force on the beam when the mag is on vs when it is off?
So a single cycle of mag on then off is a single data point. We have one measure of average force on the beam for mag on and one average force on the beam with mag off. This cycling on then off is repeated many times.
We now have many measures of force on the beam for mag on and also mag off.
Now we apply the t-test to determine if there is a statistical difference between our two groups, average force on the beam with mag on and average force on the beam with mag off.
What do you feel could be improved in the justification? What the t-test lets us do is answer, in a statistically formal way: "is the average force during mag on different than average force during mag off?"
Mathematically, it's identical your binomial theorem route except variance is naturally included into the t-test, whereas the binomial route incorporates variance implicitly. The reason for using the t-test is that not only is it easier, but it's the accepted practice for comparing two means.QuoteIf you look at the raw data, the slopes are almost all negative, consistent with the thermal trending,but the rate fits a polynomial, so the meaning of the slope comparison changes depending where you are on that fit.
Personally, I wouldn't touch any of the data with any kind of curve fit. When you use a curve fit, you're making implicit assumptions about the data that you can't justify within the data.
Given any finite data set, you can find a polynomial that fits that data perfectly if you go high enough in your order. So the data fitting a polynomial is meaningless unless you can back up why it should fit a polynomial.
1. Max - Min
2. variance
3. 1 sd interval
this in your note got me thinking:
So a single cycle of mag on then off is a single data point. We have one measure of average force on the beam for mag on and one average force on the beam with mag off. This cycling on then off is repeated many times.
We now have many measures of force on the beam for mag on and also mag off.
You're right, it is a single measurement of the force on the beam. Now the question is, how do we properly use those multiple data points to create a single measurement.
rate of change aka slope was my preferred method, but the oscillatory character of the beam makes that difficult, at least in the time windows of Mag/on - Mag/off
Average just tells us where on the polynomial we are, sorta (I usually use polynomials to find residuals, not to fit data).
Now here's some things to look at among others to derive a "measurement" of that window. Not sure how to postfacto justify them, but...1. Max - Min
2. variance
3. 1 sd interval
Got any other measurement surrogates? :)
rate of change aka slope was my preferred method, but the oscillatory character of the beam makes that difficult, at least in the time windows of Mag/on - Mag/off
Average just tells us where on the polynomial we are, sorta (I usually use polynomials to find residuals, not to fit data).
Now here's some things to look at among others to derive a "measurement" of that window. Not sure how to postfacto justify them, but...
BTW I just tried max-min and sd, the results were surpising. Now why is that.... Gotta think a bit before sharing.
One thing to keep in mind Wolfy, is the magnetron is not an instant-on device. There is typically a 3 second delay from hum to max emissions. I would not characterize mag ON as a single data point, but a dataset that needs to be analysed for mag power characterization. There should be 10 datapoints or so in this subset.this in your note got me thinking:
So a single cycle of mag on then off is a single data point. We have one measure of average force on the beam for mag on and one average force on the beam with mag off. This cycling on then off is repeated many times.
We now have many measures of force on the beam for mag on and also mag off.
You're right, it is a single measurement of the force on the beam. Now the question is, how do we properly use those multiple data points to create a single measurement.
rate of change aka slope was my preferred method, but the oscillatory character of the beam makes that difficult, at least in the time windows of Mag/on - Mag/off
Average just tells us where on the polynomial we are, sorta (I usually use polynomials to find residuals, not to fit data).
Now here's some things to look at among others to derive a "measurement" of that window. Not sure how to postfacto justify them, but...1. Max - Min
2. variance
3. 1 sd interval
Got any other measurement surrogates? :)Quoterate of change aka slope was my preferred method, but the oscillatory character of the beam makes that difficult, at least in the time windows of Mag/on - Mag/off
Slope is the best method, and in my opinion the only one given the beam stiction. It is an implicit average of the rate of change of deflection over a single mag on/off period because the slope of a line between two points is the average rate of change between those points (by the fundamental theorem of calculus).QuoteAverage just tells us where on the polynomial we are, sorta (I usually use polynomials to find residuals, not to fit data).
I don't know what this means. Maybe you could explain it to me?QuoteNow here's some things to look at among others to derive a "measurement" of that window. Not sure how to postfacto justify them, but...
ehhh, but why? We have the average rate of deflection by looking at the slope; what do we hope to gain from looking at max - min for example?
Neither variance or sd are valid proxies for thrust though, so definitely don't do that.
BTW I just tried max-min and sd, the results were surpising. Now why is that.... Gotta think a bit before sharing.Because both max-min and sd are measurements of the variability of a time series, and the periods when the magnetron is on are naturally going to be more noisy than when the magnetron is off, ceterus paribus?
Why do we know that "the periods when the magnetron is on are naturally going to be more noisy"? ???
In my mind's eye, we might have a step function being injected. I don't see a rigorous apriore justification for why the "noise" is greater for the "on" versus "off" period. We can start to make assumptions about 60Hz "steps" (or impulses) during the "on" period, but the resolution of the data is so low I don't see how such 60Hz "steps" could possibly be resolved. Instead, I would have thought the mechanical system acting as a crude low pass filter would be a more likely scenario... which leads back to the original question: why should we expect to see more noise during "on" than "off"?
If we can show statistically that the data *IS* noisier while the magnetron is on, then I think that would be very valuable piece of information. For example, if there is more "noise" while the magnetron is on, a follow-on question would be: what does the "noise" look like?
So in summary, I'm quite interested in hearing what @Glennfish noticed while performing simple min/max and sd calculations. ;)
I might address this a bit, the LDS system is an industrial, shielded box and cables located about 7 feet from the frustum. The DAQ is mounted inside the shielded computer box for additional isolation. The AC is on a separate breaker feed. I'm pretty comfortable saying noise that EMI has been planned for pretty well.BTW I just tried max-min and sd, the results were surpising. Now why is that.... Gotta think a bit before sharing.Because both max-min and sd are measurements of the variability of a time series, and the periods when the magnetron is on are naturally going to be more noisy than when the magnetron is off, ceterus paribus?
Why do we know that "the periods when the magnetron is on are naturally going to be more noisy"? ???
In my mind's eye, we might have a step function being injected. I don't see a rigorous apriore justification for why the "noise" is greater for the "on" versus "off" period. We can start to make assumptions about 60Hz "steps" (or impulses) during the "on" period, but the resolution of the data is so low I don't see how such 60Hz "steps" could possibly be resolved. Instead, I would have thought the mechanical system acting as a crude low pass filter would be a more likely scenario... which leads back to the original question: why should we expect to see more noise during "on" than "off"?
If we can show statistically that the data *IS* noisier while the magnetron is on, then I think that would be very valuable piece of information. For example, if there is more "noise" while the magnetron is on, a follow-on question would be: what does the "noise" look like?
So in summary, I'm quite interested in hearing what @Glennfish noticed while performing simple min/max and sd calculations. ;)
Why do we know that "the periods when the magnetron is on are naturally going to be more noisy"? ???
In my mind's eye, we might have a step function being injected. I don't see a rigorous apriore justification for why the "noise" is greater for the "on" versus "off" period. We can start to make assumptions about 60Hz "steps" (or impulses) during the "on" period, but the resolution of the data is so low I don't see how such 60Hz "steps" could possibly be resolved. Instead, I would have thought the mechanical system acting as a crude low pass filter would be a more likely scenario... which leads back to the original question: why should we expect to see more noise during "on" than "off"?
If we can show statistically that the data *IS* noisier while the magnetron is on, then I think that would be very valuable piece of information. For example, if there is more "noise" while the magnetron is on, a follow-on question would be: what does the "noise" look like?
So in summary, I'm quite interested in hearing what @Glennfish noticed while performing simple min/max and sd calculations. ;)
Step functions generate a lot of transient noise within a brief period of the application of the step. Trying dropping a mass onto a spring system or applying a constant voltage to an RLC circuit (it's not technically noise because it's not random, but in practice the transient is usually so complicated or hard to calculate that it's treated as noise).
Think about it like this, with the magnetron is off, their is some noise. I see no mechanism that would decrease the amount of noise in the system when we turn on the magnetron. The magnetron itself brings noise, so clearly there is more noise when the magnetron is on (noise with magnetron off + noise of magnetron on). It seems obvious to me, but I guess not.
I suppose we'll have the answer when glennfish reports his analysis.
Your "uh...whatever"...might be the best news this community has had in a while considering the secretive nature of the "military industrial complex" Eisenhower mentioned a few decades ago ;)Why do we know that "the periods when the magnetron is on are naturally going to be more noisy"? ???
In my mind's eye, we might have a step function being injected. I don't see a rigorous apriore justification for why the "noise" is greater for the "on" versus "off" period. We can start to make assumptions about 60Hz "steps" (or impulses) during the "on" period, but the resolution of the data is so low I don't see how such 60Hz "steps" could possibly be resolved. Instead, I would have thought the mechanical system acting as a crude low pass filter would be a more likely scenario... which leads back to the original question: why should we expect to see more noise during "on" than "off"?
If we can show statistically that the data *IS* noisier while the magnetron is on, then I think that would be very valuable piece of information. For example, if there is more "noise" while the magnetron is on, a follow-on question would be: what does the "noise" look like?
So in summary, I'm quite interested in hearing what @Glennfish noticed while performing simple min/max and sd calculations. ;)
Step functions generate a lot of transient noise within a brief period of the application of the step. Trying dropping a mass onto a spring system or applying a constant voltage to an RLC circuit (it's not technically noise because it's not random, but in practice the transient is usually so complicated or hard to calculate that it's treated as noise).
Think about it like this, with the magnetron is off, their is some noise. I see no mechanism that would decrease the amount of noise in the system when we turn on the magnetron. The magnetron itself brings noise, so clearly there is more noise when the magnetron is on (noise with magnetron off + noise of magnetron on). It seems obvious to me, but I guess not.
I suppose we'll have the answer when glennfish reports his analysis.
Patience please. :) My food chain in life includes a boss 12 hours off from my time zone. Right now I'm engaged in doing something else.
I'll get to this ASAP. The noise issue is interesting. Can someone point to relevant nyquist calculators while I'm engaged on the other side of the planet?
RFMWGUY. I do have to say, sometimes I feel like a voyeur. You're living the sexy experiment. I'm just measuring the... uh... whatever :)
Your "uh...whatever"...might be the best news this community has had in a while considering the secretive nature of the "military industrial complex" Eisenhower mentioned a few decades ago ;)Why do we know that "the periods when the magnetron is on are naturally going to be more noisy"? ???
In my mind's eye, we might have a step function being injected. I don't see a rigorous apriore justification for why the "noise" is greater for the "on" versus "off" period. We can start to make assumptions about 60Hz "steps" (or impulses) during the "on" period, but the resolution of the data is so low I don't see how such 60Hz "steps" could possibly be resolved. Instead, I would have thought the mechanical system acting as a crude low pass filter would be a more likely scenario... which leads back to the original question: why should we expect to see more noise during "on" than "off"?
If we can show statistically that the data *IS* noisier while the magnetron is on, then I think that would be very valuable piece of information. For example, if there is more "noise" while the magnetron is on, a follow-on question would be: what does the "noise" look like?
So in summary, I'm quite interested in hearing what @Glennfish noticed while performing simple min/max and sd calculations. ;)
Step functions generate a lot of transient noise within a brief period of the application of the step. Trying dropping a mass onto a spring system or applying a constant voltage to an RLC circuit (it's not technically noise because it's not random, but in practice the transient is usually so complicated or hard to calculate that it's treated as noise).
Think about it like this, with the magnetron is off, their is some noise. I see no mechanism that would decrease the amount of noise in the system when we turn on the magnetron. The magnetron itself brings noise, so clearly there is more noise when the magnetron is on (noise with magnetron off + noise of magnetron on). It seems obvious to me, but I guess not.
I suppose we'll have the answer when glennfish reports his analysis.
Patience please. :) My food chain in life includes a boss 12 hours off from my time zone. Right now I'm engaged in doing something else.
I'll get to this ASAP. The noise issue is interesting. Can someone point to relevant nyquist calculators while I'm engaged on the other side of the planet?
RFMWGUY. I do have to say, sometimes I feel like a voyeur. You're living the sexy experiment. I'm just measuring the... uh... whatever :)
It has been a shame we've been forced to do our own investigations outside of traditional sources...but hey...ya gotta do what ya gotta do...
...
If we can show statistically that the data *IS* noisier while the magnetron is on, then I think that would be very valuable piece of information. For example, if there is more "noise" while the magnetron is on, a follow-on question would be: what does the "noise" look like?
...
Step functions generate a lot of transient noise within a brief period of the application of the step. Trying dropping a mass onto a spring system or applying a constant voltage to an RLC circuit (it's not technically noise because it's not random, but in practice the transient is usually so complicated or hard to calculate that it's treated as noise).
Think about it like this, when the magnetron is off, their is some noise. I see no mechanism that would decrease the amount of noise in the system when we turn on the magnetron. The magnetron itself brings noise, so clearly there is more noise when the magnetron is on (noise with magnetron off + noise of magnetron on). It seems obvious to me, but I guess not.
I suppose we'll have the answer when glennfish reports his analysis.
Done some frequency sweeps between 22.0 GHz and 25.6 GHz and recorded the RX power, current and force in order to find some clues for the resonance frequency.
I did it first without antenna and then with an omnidirectional antenna and finally with the cavity (with tuning screw and with fixed endplates)
There is something happening around 24.6 GHz in the RX graph (600s sweep) which comes together with a force change (fixed endplate cavity) - but I need to check it in detail before I post some information based just on assumptions.
I wanted to release the software for viewing the data today, but it has still a bug in the display for recordings longer than 480 seconds, so I´ll fix this first before I release it.
Don´t worry, it won´t take long.
I suspect we're all thinking along the same lines. Normally a transient response exists for both the assertion and de-assertion of a step (i.e. turn on vs turn off). Trying to isolate differences in the transient response for "on" versus "off" is probably a worthwhile endeavor since we won't have any new data for a while. If the "on" and "off" have equal noise/signal content (freq, magnitude, etc) and have no discernible differences, then I think we can safely call a null result.
My thought is we might was well mine the data we have looking for any and all patterns. I'm all for prioritizing those deemed "least controversial", but no harm throwing any algorithm we can at the problem. An example would be to employ something like a search algorithm on each edge of the magnetron hum on/off time to see if there's a way to recognize different effects due to variable delay in energy on/off and/or potential frequency differences.
False positives are a necessary evil when looking for an answer to a question without a detailed understanding of how something works. Correlation does *NOT* equal causation (i.e. a strong correlation between magnetron on/off and movement might simply be due to increased water vapor thrust while "on"). This data is so noisy I'd be happy to see correlation of any kind as a first step.... understanding anything close to causation will likely take much longer and require lots of future experiments.
I suppose we'll have the answer when glennfish reports his analysis.I was wrong. :)
Never accept anything anyone says. :);)
Thought about water vapor expulsion...with the narrow end down, this should drive frustum upwards in ON state. Not sure I could quantify its lift value however....
If we can show statistically that the data *IS* noisier while the magnetron is on, then I think that would be very valuable piece of information. For example, if there is more "noise" while the magnetron is on, a follow-on question would be: what does the "noise" look like?
...
Step functions generate a lot of transient noise within a brief period of the application of the step. Trying dropping a mass onto a spring system or applying a constant voltage to an RLC circuit (it's not technically noise because it's not random, but in practice the transient is usually so complicated or hard to calculate that it's treated as noise).
Think about it like this, when the magnetron is off, their is some noise. I see no mechanism that would decrease the amount of noise in the system when we turn on the magnetron. The magnetron itself brings noise, so clearly there is more noise when the magnetron is on (noise with magnetron off + noise of magnetron on). It seems obvious to me, but I guess not.
I suppose we'll have the answer when glennfish reports his analysis.
I suspect we're all thinking along the same lines. Normally a transient response exists for both the assertion and de-assertion of a step (i.e. turn on vs turn off). Trying to isolate differences in the transient response for "on" versus "off" is probably a worthwhile endeavor since we won't have any new data for a while. If the "on" and "off" have equal noise/signal content (freq, magnitude, etc) and have no discernible differences, then I think we can safely call a null result.
My thought is we might was well mine the data we have looking for any and all patterns. I'm all for prioritizing those deemed "least controversial", but no harm throwing any algorithm we can at the problem. An example would be to employ something like a search algorithm on each edge of the magnetron hum on/off time to see if there's a way to recognize different effects due to variable delay in energy on/off and/or potential frequency differences.
False positives are a necessary evil when looking for an answer to a question without a detailed understanding of how something works. Correlation does *NOT* equal causation (i.e. a strong correlation between magnetron on/off and movement might simply be due to increased water vapor thrust while "on"). This data is so noisy I'd be happy to see correlation of any kind as a first step.... understanding anything close to causation will likely take much longer and require lots of future experiments.
I suspect we're all thinking along the same lines. Normally a transient response exists for both the assertion and de-assertion of a step (i.e. turn on vs turn off). Trying to isolate differences in the transient response for "on" versus "off" is probably a worthwhile endeavor since we won't have any new data for a while. If the "on" and "off" have equal noise/signal content (freq, magnitude, etc) and have no discernible differences, then I think we can safely call a null result.
My thought is we might was well mine the data we have looking for any and all patterns. I'm all for prioritizing those deemed "least controversial", but no harm throwing any algorithm we can at the problem. An example would be to employ something like a search algorithm on each edge of the magnetron hum on/off time to see if there's a way to recognize different effects due to variable delay in energy on/off and/or potential frequency differences.
False positives are a necessary evil when looking for an answer to a question without a detailed understanding of how something works. Correlation does *NOT* equal causation (i.e. a strong correlation between magnetron on/off and movement might simply be due to increased water vapor thrust while "on"). This data is so noisy I'd be happy to see correlation of any kind as a first step.... understanding anything close to causation will likely take much longer and require lots of future experiments.
Well my intuition was wrong. Contrary to what I said, at least in the data of NSF flight test #2B, the magnetron off periods actually have greater standard deviation than magnetron on periods at the p=0.05 significance level.
That one is on me, just goes to remind me that I should always let the data speak for itself. I was completely backwards and in a surprising statistically strong way. There is some mechanism that appears to cause magnetron on periods to be less variable than magnetron off periods for the 13 runs of flight test #2B.
This was determined just as before by applying the t-test to the set of standard deviations for on and off periods. Here is a little video (https://www.youtube.com/watch?v=BlS11D2VL_U) on how to call the t-test as an excel function and a bit of an explanation of what it does.
The probability that the standard deviations for on and off are actually the same is only around 3.5%.
I attach the same spreadsheet I attached earlier with the new stdev analysis. I added some color coding that I hope is helpful. There was a minor error in the last attached spreadsheet for the #2B data (misplaced sign) that has been corrected and increased the significance of the difference between the slopes to the 0.5% level.
So to follow up:I suppose we'll have the answer when glennfish reports his analysis.I was wrong. :)
Goes to show:Never accept anything anyone says. :);)
Fascinating (eyebrow raised).I suspect we're all thinking along the same lines. Normally a transient response exists for both the assertion and de-assertion of a step (i.e. turn on vs turn off). Trying to isolate differences in the transient response for "on" versus "off" is probably a worthwhile endeavor since we won't have any new data for a while. If the "on" and "off" have equal noise/signal content (freq, magnitude, etc) and have no discernible differences, then I think we can safely call a null result.
My thought is we might was well mine the data we have looking for any and all patterns. I'm all for prioritizing those deemed "least controversial", but no harm throwing any algorithm we can at the problem. An example would be to employ something like a search algorithm on each edge of the magnetron hum on/off time to see if there's a way to recognize different effects due to variable delay in energy on/off and/or potential frequency differences.
False positives are a necessary evil when looking for an answer to a question without a detailed understanding of how something works. Correlation does *NOT* equal causation (i.e. a strong correlation between magnetron on/off and movement might simply be due to increased water vapor thrust while "on"). This data is so noisy I'd be happy to see correlation of any kind as a first step.... understanding anything close to causation will likely take much longer and require lots of future experiments.
Well my intuition was wrong. Contrary to what I said, at least in the data of NSF flight test #2B, the magnetron off periods actually have greater standard deviation than magnetron on periods at the p=0.05 significance level.
That one is on me, just goes to remind me that I should always let the data speak for itself. I was completely backwards and in a surprising statistically strong way. There is some mechanism that appears to cause magnetron on periods to be less variable than magnetron off periods for the 13 runs of flight test #2B.
This was determined just as before by applying the t-test to the set of standard deviations for on and off periods. Here is a little video (https://www.youtube.com/watch?v=BlS11D2VL_U) on how to call the t-test as an excel function and a bit of an explanation of what it does.
The probability that the standard deviations for on and off are actually the same is only around 3.5%.
I attach the same spreadsheet I attached earlier with the new stdev analysis. I added some color coding that I hope is helpful. There was a minor error in the last attached spreadsheet for the #2B data (misplaced sign) that has been corrected and increased the significance of the difference between the slopes to the 0.5% level.
So to follow up:I suppose we'll have the answer when glennfish reports his analysis.I was wrong. :)
Goes to show:Never accept anything anyone says. :);)
Caution Will Robinson.
Did you account for the fact the the ON data count # is alway greater than the OFF data count # in this data set?
When I looked at the max-min data, it was obvious that the deltas strongly (p > .9) favored the ON, but... the ON TIMES were longer than the OFF times... so if I discounted the durations, they were random.
Not clear on what you did here, but just want to ensure that you took that into account. :)
Can anyone in this forum conjure up the ghost of Thomas Bayes? We're really pushing the envelope here. :)
More detail please. :)
Fascinating (eyebrow raised).I suspect we're all thinking along the same lines. Normally a transient response exists for both the assertion and de-assertion of a step (i.e. turn on vs turn off). Trying to isolate differences in the transient response for "on" versus "off" is probably a worthwhile endeavor since we won't have any new data for a while. If the "on" and "off" have equal noise/signal content (freq, magnitude, etc) and have no discernible differences, then I think we can safely call a null result.
My thought is we might was well mine the data we have looking for any and all patterns. I'm all for prioritizing those deemed "least controversial", but no harm throwing any algorithm we can at the problem. An example would be to employ something like a search algorithm on each edge of the magnetron hum on/off time to see if there's a way to recognize different effects due to variable delay in energy on/off and/or potential frequency differences.
False positives are a necessary evil when looking for an answer to a question without a detailed understanding of how something works. Correlation does *NOT* equal causation (i.e. a strong correlation between magnetron on/off and movement might simply be due to increased water vapor thrust while "on"). This data is so noisy I'd be happy to see correlation of any kind as a first step.... understanding anything close to causation will likely take much longer and require lots of future experiments.
Well my intuition was wrong. Contrary to what I said, at least in the data of NSF flight test #2B, the magnetron off periods actually have greater standard deviation than magnetron on periods at the p=0.05 significance level.
That one is on me, just goes to remind me that I should always let the data speak for itself. I was completely backwards and in a surprising statistically strong way. There is some mechanism that appears to cause magnetron on periods to be less variable than magnetron off periods for the 13 runs of flight test #2B.
This was determined just as before by applying the t-test to the set of standard deviations for on and off periods. Here is a little video (https://www.youtube.com/watch?v=BlS11D2VL_U) on how to call the t-test as an excel function and a bit of an explanation of what it does.
The probability that the standard deviations for on and off are actually the same is only around 3.5%.
I attach the same spreadsheet I attached earlier with the new stdev analysis. I added some color coding that I hope is helpful. There was a minor error in the last attached spreadsheet for the #2B data (misplaced sign) that has been corrected and increased the significance of the difference between the slopes to the 0.5% level.
So to follow up:I suppose we'll have the answer when glennfish reports his analysis.I was wrong. :)
Goes to show:Never accept anything anyone says. :);)
Caution Will Robinson.
Did you account for the fact the the ON data count # is alway greater than the OFF data count # in this data set?
When I looked at the max-min data, it was obvious that the deltas strongly (p > .9) favored the ON, but... the ON TIMES were longer than the OFF times... so if I discounted the durations, they were random.
Not clear on what you did here, but just want to ensure that you took that into account. :)
Can anyone in this forum conjure up the ghost of Thomas Bayes? We're really pushing the envelope here. :)
More detail please. :)
Wolfy has a nice spreadsheet, followed the video link and learned something new.
Isn't a ttest capable of differing no.s in dataset comparisons?
If not, think the central portion of ON would be best considering the mag seems to need a bit of time to fire up.
Caution Will Robinson.
Did you account for the fact the the ON data count # is alway greater than the OFF data count # in this data set?
When I looked at the max-min data, it was obvious that the deltas strongly (p > .9) favored the ON, but... the ON TIMES were longer than the OFF times... so if I discounted the durations, they were random.
Not clear on what you did here, but just want to ensure that you took that into account. :)
Can anyone in this forum conjure up the ghost of Thomas Bayes? We're really pushing the envelope here. :)
More detail please. :)
Did you account for the fact the the ON data count # is alway greater than the OFF data count # in this data set?
No pressure, but I now have my olds sitting smack dab where the test stand was. :o
already tried that, using 1, 2, 3, 4, 5 second delays on the slope test. Didn't change squat on this data sent. :(
Need some time to go back to the previous test and review.
If you havent shipped the kit & kaboodle to SeaShells, I have a half dozen "please do this" recommendations for a next test. They all focus on bypassing the timer on the microwave oven. That seems to be your most onerous villian. In all the data I see, the oscillation freaking has a harmonic which matches the microwave oven on/off time. As long as that harmonic is there I will loose lots of my not much left hair.
No pressure, but I now have my olds sitting smack dab where the test stand was. :o
Uhhh...angry wife...angry life...
Would you swap for a 2.0 liter deisel VW?
Alright, I always wanted to ask this. Do you think NASA Eagleworks were able to go above 100 micronewtons and keep it constant? and pass the testing to the Glenn Research Center?I was asked the other day if Micro-newtons were just a little cookie.
I do not want to speculate. Just curious :).
My guess is they might have...but of course no paper yet to confirm or dismiss, but after the testing by rfmwguy I am more confident. On the other hand the "thrust" is still quite small so far..
Thanks for the welcome and the most appreciated comments!I would like to ask the members of the forum for some input/opinions.Yay! Welcome to the DIY world! Fear not, as I took a lot of the naysayer hits when I started posting a few months ago, so in a sense I've absorbed a lot of the pressure for those who follow 8)
Some of you know me from my posts on various RF and microwave issues. I am just now starting a DIY emdrive test effort – I am finally getting my workshop back on line following a move –and I want to try to build on the outstanding work of SeeShell, rfmwguy, and others to hopefully make some small contribution of my own.
Anyway – to the request.
There are a multitude of test environment design factors of course and this is just a start but in order to begin limiting the possible test space I have narrowed down overall test configurations to the following:
1. Rotary Table configuration – unit under test (UUT) thrusting either posigrade or retrograde to rotation
2. Linear (slide) configuration – air or other low friction surface. UUT thrusting along the access of the slide.
3. Balance Beam (ala rfmwguy and seeshells) UUT thrusting either up or down
In my thinking all have things going for them as well as potential problems, but I would like to ask for your thoughts on each configurations. In particular these are the things I have been considering:
• Overall Pros and Cons
• Challenges to getting usable data output
• Potential systemic and situational error sources
• Data which should/can be measured for either signal or noise/error determinations
ANYTHING else you can think of –
Thanks in advance. If you would prefer to reply by private message rather than on the forum that is fine with me however please indicate any information which you do not want disseminated further.
Herman
PS – for those who don’t know me and to provide some credibility background - I have worked in both professionally and DIY settings on RF from LF to 40+ Ghz, high power RF and RF power supplies, vacuum chambers and systems, nuclear power plants and various and sundry other technical fields including aerospace and defense for the past 39 years. Well acquainted with safety procedures - wrote some for my last company. This will be my first big retirement project and I can’t wait to get started.
I've thought long and hard about many of your questions. Rotary tables need an air source that will stir up all ambient air around the DUT. Same for a linear table. While I think horizontal measuring is best for ambient air measuring, the background artifacts can be a challenge.
Regarding vertical measurements, lift is an enemy, much more so that I would have thought, even with a wire mesh frustum. Extracting data out of the natural lift is difficult as you can see by the fine work done by data analysists here. I still think this is the way to go as it limits other mechanical and electrical variables.
Datalogging: suggest you go with a fast computer that can handle screen recording with ease. Datalogging is usually serial and even an old PC like mine handled it easily; not so with screen record. Quad core processor is a must. DAQ can be anything, but try to go with a 12 bit as a minumum. Locate several feet from frustum and power supplies.
Laser Displacement Sensors - highly recommend this for vertical measurements. Try to select a 40mm +/- 10mm range rather than a 100mm+ sensor. The closer, the better resolution...up to 7 digits. Try Omron or equivalent.
Setup in an area with no vents and cover windows for drafts. You can see the deflections as I simply approached the setup.
Have nothing else on AC lines feeding your gear that could draw a load (pretty basic advice).
Other than that, make sure you HAVE FUN. Thats really the bottom line Graybeard. We are here to help and support your efforts.
I **fig**ured that would come up sooner or later.Alright, I always wanted to ask this. Do you think NASA Eagleworks were able to go above 100 micronewtons and keep it constant? and pass the testing to the Glenn Research Center?I was asked the other day if Micro-newtons were just a little cookie.
I do not want to speculate. Just curious :).
My guess is they might have...but of course no paper yet to confirm or dismiss, but after the testing by rfmwguy I am more confident. On the other hand the "thrust" is still quite small so far..
Thank you !I would like to ask the members of the forum for some input/opinions.
Some of you know me from my posts on various RF and microwave issues. I am just now starting a DIY emdrive test effort – I am finally getting my workshop back on line following a move –and I want to try to build on the outstanding work of SeeShell, rfmwguy, and others to hopefully make some small contribution of my own.
Anyway – to the request.
There are a multitude of test environment design factors of course and this is just a start but in order to begin limiting the possible test space I have narrowed down overall test configurations to the following:
1. Rotary Table configuration – unit under test (UUT) thrusting either posigrade or retrograde to rotation
2. Linear (slide) configuration – air or other low friction surface. UUT thrusting along the access of the slide.
3. Balance Beam (ala rfmwguy and seeshells) UUT thrusting either up or down
In my thinking all have things going for them as well as potential problems, but I would like to ask for your thoughts on each configurations. In particular these are the things I have been considering:
• Overall Pros and Cons
• Challenges to getting usable data output
• Potential systemic and situational error sources
• Data which should/can be measured for either signal or noise/error determinations
ANYTHING else you can think of –
Thanks in advance. If you would prefer to reply by private message rather than on the forum that is fine with me however please indicate any information which you do not want disseminated further.
Herman
PS – for those who don’t know me and to provide some credibility background - I have worked in both professionally and DIY settings on RF from LF to 40+ Ghz, high power RF and RF power supplies, vacuum chambers and systems, nuclear power plants and various and sundry other technical fields including aerospace and defense for the past 39 years. Well acquainted with safety procedures - wrote some for my last company. This will be my first big retirement project and I can’t wait to get started.
A rotary rig will allow unlimited contious accelleration (well, depending on friction in your rig) and therefore most likely a higher signal to noise ratio. It would also be easy to do control experiments like rotating the frustum 180 deg. for reverse thrust, or 90 degrees (pointing towards or away from the rotational axis) for zero thrust.
On the other hand, it will arguably be the most complicated setup to build.
Whichever configuration you choose, be very careful when you design your experiment. What is your hypothesis? How can you falsify it? What control experiments do you need? The most accurate measurements in the world won't save you if you don't know what it is you're measuring.
As I have mentioned earlier, in my opinion, the most important control experiment to do is one where you are knowingly injecting EM at a non-resonating frequency. That should be your "negative control" experiment. Naturally, this means you must know the resonant freq. of your cavity and so on.
It is of course also important that you do at least 3 independent repetitions of each experiment, the more the better.
Good luck!
BTW I just tried max-min and sd, the results were surpising. Now why is that.... Gotta think a bit before sharing.Because both max-min and sd are measurements of the variability of a time series, and the periods when the magnetron is on are naturally going to be more noisy than when the magnetron is off, ceterus paribus?
Why do we know that "the periods when the magnetron is on are naturally going to be more noisy"? ???
In my mind's eye, we might have a step function being injected. I don't see a rigorous apriore justification for why the "noise" is greater for the "on" versus "off" period. We can start to make assumptions about 60Hz "steps" (or impulses) during the "on" period, but the resolution of the data is so low I don't see how such 60Hz "steps" could possibly be resolved. Instead, I would have thought the mechanical system acting as a crude low pass filter would be a more likely scenario... which leads back to the original question: why should we expect to see more noise during "on" than "off"?
If we can show statistically that the data *IS* noisier while the magnetron is on, then I think that would be very valuable piece of information. For example, if there is more "noise" while the magnetron is on, a follow-on question would be: what does the "noise" look like?
So in summary, I'm quite interested in hearing what @Glennfish noticed while performing simple min/max and sd calculations. ;)
Anyway – to the request.
...
• Data which should/can be measured for either signal or noise/error determinations
Anyway – to the request.
...
• Data which should/can be measured for either signal or noise/error determinations
As one of the data geeks here, one thing that's become apparant is that the data should be as complete and sharable as possible. The limited analysis I've done has depended on multiple other people massaging the data before I touch it. I'd like to propose some sort of data interchange standard, but I don't know squat about what we should be measuring. I don't know how fast you should sample, but as a rule of thumb, sample as fast as you can for as long as you can.
In general, include for each sample
1. time stamp (maximum possible accuracy... microsecond resolution would be cool)
2. state of the device (on/off)
3. other states, i.e. forward, backward, as many states as you can collect
...
4. measurement 1
5. measurement 2 as many simultaneous measurements as you can grab
... etc
CSV format is ideal, it works with almost everything
xls format is ok, most of us can work with that
Wow, impressive spreadsheet, especially sheet 2 graphs (my visual brain speaking). Can you conclude your first glimpse into ft 2d shows a statistical variance between on/off beyond the probability threshold?BTW I just tried max-min and sd, the results were surpising. Now why is that.... Gotta think a bit before sharing.Because both max-min and sd are measurements of the variability of a time series, and the periods when the magnetron is on are naturally going to be more noisy than when the magnetron is off, ceterus paribus?
Why do we know that "the periods when the magnetron is on are naturally going to be more noisy"? ???
In my mind's eye, we might have a step function being injected. I don't see a rigorous apriore justification for why the "noise" is greater for the "on" versus "off" period. We can start to make assumptions about 60Hz "steps" (or impulses) during the "on" period, but the resolution of the data is so low I don't see how such 60Hz "steps" could possibly be resolved. Instead, I would have thought the mechanical system acting as a crude low pass filter would be a more likely scenario... which leads back to the original question: why should we expect to see more noise during "on" than "off"?
If we can show statistically that the data *IS* noisier while the magnetron is on, then I think that would be very valuable piece of information. For example, if there is more "noise" while the magnetron is on, a follow-on question would be: what does the "noise" look like?
So in summary, I'm quite interested in hearing what @Glennfish noticed while performing simple min/max and sd calculations. ;)
on noise.
Noise is typically calculated on the basis of a known signal, and a measurement of how that signal degrades. We don't really have that in this data.
A surrogate to noise is the standard deviation or variance.
Comparing two variances is generally verboten, but there are a some ways.
I chose, to answer your question, something called the Coefficient of Variation. I'm not sure it's a good method with this data. It's basically, the standard deviation / mean
It doesn't take the sample size into account, but it does sorta what you were asking about.
Spreadsheet attached ("macro's not included")
raw data in sheet raw2.php
summary in sheet Sheet1
Wow, impressive spreadsheet, especially sheet 2 graphs (my visual brain speaking). Can you conclude your first glimpse into ft 2d shows a statistical variance between on/off beyond the probability threshold?BTW I just tried max-min and sd, the results were surpising. Now why is that.... Gotta think a bit before sharing.Because both max-min and sd are measurements of the variability of a time series, and the periods when the magnetron is on are naturally going to be more noisy than when the magnetron is off, ceterus paribus?
Why do we know that "the periods when the magnetron is on are naturally going to be more noisy"? ???
In my mind's eye, we might have a step function being injected. I don't see a rigorous apriore justification for why the "noise" is greater for the "on" versus "off" period. We can start to make assumptions about 60Hz "steps" (or impulses) during the "on" period, but the resolution of the data is so low I don't see how such 60Hz "steps" could possibly be resolved. Instead, I would have thought the mechanical system acting as a crude low pass filter would be a more likely scenario... which leads back to the original question: why should we expect to see more noise during "on" than "off"?
If we can show statistically that the data *IS* noisier while the magnetron is on, then I think that would be very valuable piece of information. For example, if there is more "noise" while the magnetron is on, a follow-on question would be: what does the "noise" look like?
So in summary, I'm quite interested in hearing what @Glennfish noticed while performing simple min/max and sd calculations. ;)
on noise.
Noise is typically calculated on the basis of a known signal, and a measurement of how that signal degrades. We don't really have that in this data.
A surrogate to noise is the standard deviation or variance.
Comparing two variances is generally verboten, but there are a some ways.
I chose, to answer your question, something called the Coefficient of Variation. I'm not sure it's a good method with this data. It's basically, the standard deviation / mean
It doesn't take the sample size into account, but it does sorta what you were asking about.
Spreadsheet attached ("macro's not included")
raw data in sheet raw2.php
summary in sheet Sheet1
The specification of hypothesis and goals of each test is one of the reasons I will be formally documenting a test plan. I have been following the hypothesis discussion hear closely and I will say more on that later but there MUST be control experiments and null drive configurations. In particular I am very interested in what happens off design point with frequencies far from resonance. Likewise with heating the frustum in a manner which will be null for thrust but can heat it up etc.
I also completely agree with 3x or better tests. Likewise when test configuration or conditions are changed only one is changed at a time. This takes time but results in hopefully more useful data.
Herman
Your thinking will pay off for future experimenters. The data overlay approach with mag ON/OFF is important. While OFF (lift) is moderately well behaved, ON has additional variables in the time domain such as mag frequency and power levels across a 40 MHz spectrum. Wish it were a square wave, instant ON with no level, thermal or frequency variations, but that is not the nature of the beast. RF power level in a mag is a delayed buildup akin to a cap charge best I can determine by reading and personal observation. Its frequencies slip across a natural frustum resonance; which itself changes with temperature.Wow, impressive spreadsheet, especially sheet 2 graphs (my visual brain speaking). Can you conclude your first glimpse into ft 2d shows a statistical variance between on/off beyond the probability threshold?BTW I just tried max-min and sd, the results were surpising. Now why is that.... Gotta think a bit before sharing.Because both max-min and sd are measurements of the variability of a time series, and the periods when the magnetron is on are naturally going to be more noisy than when the magnetron is off, ceterus paribus?
Why do we know that "the periods when the magnetron is on are naturally going to be more noisy"? ???
In my mind's eye, we might have a step function being injected. I don't see a rigorous apriore justification for why the "noise" is greater for the "on" versus "off" period. We can start to make assumptions about 60Hz "steps" (or impulses) during the "on" period, but the resolution of the data is so low I don't see how such 60Hz "steps" could possibly be resolved. Instead, I would have thought the mechanical system acting as a crude low pass filter would be a more likely scenario... which leads back to the original question: why should we expect to see more noise during "on" than "off"?
If we can show statistically that the data *IS* noisier while the magnetron is on, then I think that would be very valuable piece of information. For example, if there is more "noise" while the magnetron is on, a follow-on question would be: what does the "noise" look like?
So in summary, I'm quite interested in hearing what @Glennfish noticed while performing simple min/max and sd calculations. ;)
on noise.
Noise is typically calculated on the basis of a known signal, and a measurement of how that signal degrades. We don't really have that in this data.
A surrogate to noise is the standard deviation or variance.
Comparing two variances is generally verboten, but there are a some ways.
I chose, to answer your question, something called the Coefficient of Variation. I'm not sure it's a good method with this data. It's basically, the standard deviation / mean
It doesn't take the sample size into account, but it does sorta what you were asking about.
Spreadsheet attached ("macro's not included")
raw data in sheet raw2.php
summary in sheet Sheet1
The sheet reflects my scatterbrained approach to figuring out what should be looked at.
There is no question that the on CV is greater than the off CV. p > .99
BUT, I'm not sure if that's real or an artifact of the different data counts during a downward trend.
Gotta think some more.
The specification of hypothesis and goals of each test is one of the reasons I will be formally documenting a test plan. I have been following the hypothesis discussion hear closely and I will say more on that later but there MUST be control experiments and null drive configurations. In particular I am very interested in what happens off design point with frequencies far from resonance. Likewise with heating the frustum in a manner which will be null for thrust but can heat it up etc.
I also completely agree with 3x or better tests. Likewise when test configuration or conditions are changed only one is changed at a time. This takes time but results in hopefully more useful data.
Herman
I'm not sure a null test is possible in a frustum unless it's unpowered. Anything else will generate heat, and you're now testing theories about the importance of frequency and Q.
The specification of hypothesis and goals of each test is one of the reasons I will be formally documenting a test plan. I have been following the hypothesis discussion hear closely and I will say more on that later but there MUST be control experiments and null drive configurations. In particular I am very interested in what happens off design point with frequencies far from resonance. Likewise with heating the frustum in a manner which will be null for thrust but can heat it up etc.
I also completely agree with 3x or better tests. Likewise when test configuration or conditions are changed only one is changed at a time. This takes time but results in hopefully more useful data.
Herman
I'm not sure a null test is possible in a frustum unless it's unpowered. Anything else will generate heat, and you're now testing theories about the importance of frequency and Q.
Likely you are correct. But I think I didn't say what I was trying to say very well. Back a ways on the forum - maybe even back on Thread 3 - there as discussions of running a test in which there was heating but no RF energy actually coupled into the cavity. Discussion - IIRC - even included ideas for ohmic DC heating of the cavity and waveguides. The idea at that time was to attempt to duplicate the thermal input that was occurring during the "live" test but without the possibility for the potentially existing em generated thrust and thereby attempt to quantify the "lift" or "thrust" due to the thermal heating . At the time I was wondering about the potential fidelity of these sorts of tests, but I did think that if it could be done in am manner to duplicated the "flight" configuration but without coupling RF it might provide some useful control data. It might also be a bit of pursuing the wild goose.
H
Regarding the null test. Aren't we pretty sure that a cylindrical resonator will not thrust? It will heat and do all the other things, but if something is escaping, that something should escape symmetrically, no thrust. If nothing is escaping then still no thrust due to symmetry.
Of course getting the heating rates right may be a little tricky when it comes to comparing to a real EM Drive configuration.
I do think the idea posted much earlier by (I forget who posted it), the idea of two identical frustums, one at each end of a balance beam, would go a long way toward eliminating thermal lift from the data. The idea was to mount both frustums upward, run to steady state then turn one off. Or mount one up, one down and run synchronously, doubling the thrust effect while significantly reducing the lift effect. This one would allow data collection from initial power on of the cold system and still reduce the effect of thermal lift.
Only problem is that it takes two frustums, but rfmwguy can tell us how much difficulty and cost would be involved in building the second identical frustum. And he could likely scope out the required modifications to the test rig as well.
@glennfish, attached is the original ft 2d spreadsheet with data channels 2-4 (columns b-d) unhidden. Its in the original file as well, just hidden.
Note on these hidden data channels: The data inputs are unloaded, meaning nothing is attached to them, unlike channel 1 (column a on the spreadsheet), the LDS voltage input. This might be useful in looking at system noise in mag ON/OFF conditions.
While I cannot quantify the randomness, it will be the most variable (very sensitive) since there is no load (resistor) on the inputs. If mag ON imparts system noise, these 3 channels and over 8,100 data points will be the most sensitive to noise and will show it.
Another note. The balanced impedance of channel 1 is 470 ohms. Data on channels 2-4 (columns b-c) are open (infinite impedance by comparison) and are not directly equivalent to channel 1. However general deviation comparisons to mag ON/OFF should give you a relative indication of any system noise attributable to EMI, if present.
Regarding the null test. Aren't we pretty sure that a cylindrical resonator will not thrust? It will heat and do all the other things, but if something is escaping, that something should escape symmetrically, no thrust. If nothing is escaping then still no thrust due to symmetry.It would be quite the challenge to build 2 identical units, mechanically and electrically. Even if you obtained a matched pair of mags, small mechanic differences in the frustum could negate a match. Then there's the thermal lift variables at two different places...opposite ends of frustum.
Of course getting the heating rates right may be a little tricky when it comes to comparing to a real EM Drive configuration.
I do think the idea posted much earlier by (I forget who posted it), the idea of two identical frustums, one at each end of a balance beam, would go a long way toward eliminating thermal lift from the data. The idea was to mount both frustums upward, run to steady state then turn one off. Or mount one up, one down and run synchronously, doubling the thrust effect while significantly reducing the lift effect. This one would allow data collection from initial power on of the cold system and still reduce the effect of thermal lift.
Only problem is that it takes two frustums, but rfmwguy can tell us how much difficulty and cost would be involved in building the second identical frustum. And he could likely scope out the required modifications to the test rig as well.
Somewhere in my archives I have a web based testing software that does all that and more. It was developed to datamine test and inject for huge cellular test labs. The company division it was developed for no longer exists and the company has been diced and sliced many times. There were 2 versions of it one in C++ and one in Java. I don't think I can release it but could pull out the key information. It was data store independent with all data available in CSV ascii. All tests recorded configuration, state, statuses, tester(s), labs, devices and gigabytes of data, GPS derived timestamps on all data and the like. You could configure, control, run and access data from any lab on the web via your browser. Informics, Oracle, MySql, Microsoft SQL and Postgres were supported database formats. It might be interesting to see something like that for distributed research like this.
Anyway – to the request.
...
• Data which should/can be measured for either signal or noise/error determinations
As one of the data geeks here, one thing that's become apparant is that the data should be as complete and sharable as possible. The limited analysis I've done has depended on multiple other people massaging the data before I touch it. I'd like to propose some sort of data interchange standard, but I don't know squat about what we should be measuring. I don't know how fast you should sample, but as a rule of thumb, sample as fast as you can for as long as you can.
In general, include for each sample
1. time stamp (maximum possible accuracy... microsecond resolution would be cool)
2. state of the device (on/off)
3. other states, i.e. forward, backward, as many states as you can collect
...
4. measurement 1
5. measurement 2 as many simultaneous measurements as you can grab
... etc
CSV format is ideal, it works with almost everything
xls format is ok, most of us can work with that
Outstanding idea. Likewise I would also suggest to naming data files or other data artifacts in a unique and unambiguous way and record somewhere a detailed description of your test configuration with the same name or description.
In my former life we tended to use something like "PROJ-TEST-TESTNUMBER-DATE/TIME" Where PROJ was a unique project name, TEST was a unique name for the overall test configuration being used, TESTNUMBER was a sequential number of tests in the TEST configuration or better yet a unique number in the whole PROJ area, and DATE/TIME were just that - a unique date and time stamp of the start or stop of the test - whatever your datalogger will support. It seems very pedantic and like a lot of extra work but 3 months later ( or 3 days sometimes) you will be able to unambiguously know which test generated each data set.
Its a good thing, as it confirms the hypothesis that ON does not provide instantaneous results, as in a square-wave voltage change. Mag heating, frequency and resonance shift all combine (my belief) for variances shown in the points you made above. On the other hand, mag OFF is rather calm and predictable, with mother nature taking over and gently thermal lifting the DUT.@glennfish, attached is the original ft 2d spreadsheet with data channels 2-4 (columns b-d) unhidden. Its in the original file as well, just hidden.
Note on these hidden data channels: The data inputs are unloaded, meaning nothing is attached to them, unlike channel 1 (column a on the spreadsheet), the LDS voltage input. This might be useful in looking at system noise in mag ON/OFF conditions.
While I cannot quantify the randomness, it will be the most variable (very sensitive) since there is no load (resistor) on the inputs. If mag ON imparts system noise, these 3 channels and over 8,100 data points will be the most sensitive to noise and will show it.
Another note. The balanced impedance of channel 1 is 470 ohms. Data on channels 2-4 (columns b-c) are open (infinite impedance by comparison) and are not directly equivalent to channel 1. However general deviation comparisons to mag ON/OFF should give you a relative indication of any system noise attributable to EMI, if present.
Thank you. Now ponder this with me (before I downloaded your data):
1. The data trend overall is a negative slope.
2. You suggested in the last 24 hours that -- the turn-on time to resonance could be seconds
3. So what I did is for each group (on or off), asked, "was the first half of the slope > the 2nd half of the slope?" i.e. was there a slope change from negative to more negative about midpoint in the interval?
Preliminary results
For off groups, that was true 14 out of 47 times
For on groups, that was true 29 out of 47 times
For results, Fisher's exact test for those wanting to learn stats... :)
I have to check my work a few times, and when I do, I'll upload the analysis.
I've confused myself. Would this result be a good thing or a bad thing?
Its a good thing, as it confirms the hypothesis that ON does not provide instantaneous results, as in a square-wave voltage change. Mag heating, frequency and resonance shift all combine (my belief) for variances shown in the points you made above. On the other hand, mag OFF is rather calm and predictable, with mother nature taking over and gently thermal lifting the DUT.@glennfish, attached is the original ft 2d spreadsheet with data channels 2-4 (columns b-d) unhidden. Its in the original file as well, just hidden.
Note on these hidden data channels: The data inputs are unloaded, meaning nothing is attached to them, unlike channel 1 (column a on the spreadsheet), the LDS voltage input. This might be useful in looking at system noise in mag ON/OFF conditions.
While I cannot quantify the randomness, it will be the most variable (very sensitive) since there is no load (resistor) on the inputs. If mag ON imparts system noise, these 3 channels and over 8,100 data points will be the most sensitive to noise and will show it.
Another note. The balanced impedance of channel 1 is 470 ohms. Data on channels 2-4 (columns b-c) are open (infinite impedance by comparison) and are not directly equivalent to channel 1. However general deviation comparisons to mag ON/OFF should give you a relative indication of any system noise attributable to EMI, if present.
Thank you. Now ponder this with me (before I downloaded your data):
1. The data trend overall is a negative slope.
2. You suggested in the last 24 hours that -- the turn-on time to resonance could be seconds
3. So what I did is for each group (on or off), asked, "was the first half of the slope > the 2nd half of the slope?" i.e. was there a slope change from negative to more negative about midpoint in the interval?
Preliminary results
For off groups, that was true 14 out of 47 times
For on groups, that was true 29 out of 47 times
For results, Fisher's exact test for those wanting to learn stats... :)
I have to check my work a few times, and when I do, I'll upload the analysis.
I've confused myself. Would this result be a good thing or a bad thing?
Not sure if the 50% point is the best point to sub-divide, but the ON state variances versus the OFF state variances is a decent way to look at the data subset.
Nice glenn, for us stat-light posters out here, what does the data tell you?Its a good thing, as it confirms the hypothesis that ON does not provide instantaneous results, as in a square-wave voltage change. Mag heating, frequency and resonance shift all combine (my belief) for variances shown in the points you made above. On the other hand, mag OFF is rather calm and predictable, with mother nature taking over and gently thermal lifting the DUT.@glennfish, attached is the original ft 2d spreadsheet with data channels 2-4 (columns b-d) unhidden. Its in the original file as well, just hidden.
Note on these hidden data channels: The data inputs are unloaded, meaning nothing is attached to them, unlike channel 1 (column a on the spreadsheet), the LDS voltage input. This might be useful in looking at system noise in mag ON/OFF conditions.
While I cannot quantify the randomness, it will be the most variable (very sensitive) since there is no load (resistor) on the inputs. If mag ON imparts system noise, these 3 channels and over 8,100 data points will be the most sensitive to noise and will show it.
Another note. The balanced impedance of channel 1 is 470 ohms. Data on channels 2-4 (columns b-c) are open (infinite impedance by comparison) and are not directly equivalent to channel 1. However general deviation comparisons to mag ON/OFF should give you a relative indication of any system noise attributable to EMI, if present.
Thank you. Now ponder this with me (before I downloaded your data):
1. The data trend overall is a negative slope.
2. You suggested in the last 24 hours that -- the turn-on time to resonance could be seconds
3. So what I did is for each group (on or off), asked, "was the first half of the slope > the 2nd half of the slope?" i.e. was there a slope change from negative to more negative about midpoint in the interval?
Preliminary results
For off groups, that was true 14 out of 47 times
For on groups, that was true 29 out of 47 times
For results, Fisher's exact test for those wanting to learn stats... :)
I have to check my work a few times, and when I do, I'll upload the analysis.
I've confused myself. Would this result be a good thing or a bad thing?
Not sure if the 50% point is the best point to sub-divide, but the ON state variances versus the OFF state variances is a decent way to look at the data subset.
OK spreadsheet with analysis (no VBA)
Sheet: raw.php
raw data and processing
Sheet: Sheet1
summary & results
m1>m2 m1<=m2
Group ON 29 18
Group OFF 14 33
Fisher's exact test, two tailed p = .0035
Fisher's exact test, one tailed p = .0018
Ok, more confirmation of ON cycle changes. Looks like all roads leading to the conclusion that something is definitely happening, i.e. not a null test...positive not null. Fair statement?Nice glenn, for us stat-light posters out here, what does the data tell you?Its a good thing, as it confirms the hypothesis that ON does not provide instantaneous results, as in a square-wave voltage change. Mag heating, frequency and resonance shift all combine (my belief) for variances shown in the points you made above. On the other hand, mag OFF is rather calm and predictable, with mother nature taking over and gently thermal lifting the DUT.@glennfish, attached is the original ft 2d spreadsheet with data channels 2-4 (columns b-d) unhidden. Its in the original file as well, just hidden.
Note on these hidden data channels: The data inputs are unloaded, meaning nothing is attached to them, unlike channel 1 (column a on the spreadsheet), the LDS voltage input. This might be useful in looking at system noise in mag ON/OFF conditions.
While I cannot quantify the randomness, it will be the most variable (very sensitive) since there is no load (resistor) on the inputs. If mag ON imparts system noise, these 3 channels and over 8,100 data points will be the most sensitive to noise and will show it.
Another note. The balanced impedance of channel 1 is 470 ohms. Data on channels 2-4 (columns b-c) are open (infinite impedance by comparison) and are not directly equivalent to channel 1. However general deviation comparisons to mag ON/OFF should give you a relative indication of any system noise attributable to EMI, if present.
Thank you. Now ponder this with me (before I downloaded your data):
1. The data trend overall is a negative slope.
2. You suggested in the last 24 hours that -- the turn-on time to resonance could be seconds
3. So what I did is for each group (on or off), asked, "was the first half of the slope > the 2nd half of the slope?" i.e. was there a slope change from negative to more negative about midpoint in the interval?
Preliminary results
For off groups, that was true 14 out of 47 times
For on groups, that was true 29 out of 47 times
For results, Fisher's exact test for those wanting to learn stats... :)
I have to check my work a few times, and when I do, I'll upload the analysis.
I've confused myself. Would this result be a good thing or a bad thing?
Not sure if the 50% point is the best point to sub-divide, but the ON state variances versus the OFF state variances is a decent way to look at the data subset.
OK spreadsheet with analysis (no VBA)
Sheet: raw.php
raw data and processing
Sheet: Sheet1
summary & results
m1>m2 m1<=m2
Group ON 29 18
Group OFF 14 33
Fisher's exact test, two tailed p = .0035
Fisher's exact test, one tailed p = .0018
stat-light... sounds like a beer :)
OK, there is a very significant difference between the slope behavior for on vs. off, given by the values of p. Close to 1 is bad. Close to 0 is good.
What this indicates is:
If ON, the slope is likely to become more negative during the cycle.
If OFF, the slope is likely to not change or become less negative during the cycle.
examples
define m1 as the slope during the 1st half of the cycle and m2 as the slope during the last half of the cycle.
if m1 = -2 and m2 = -3 then m1>m2 = TRUE
if m1 = -2 and m2 = -1 then m1>m2 = FALSE
Ok, more confirmation of ON cycle changes. Looks like all roads leading to the conclusion that something is definitely happening, i.e. not a null test...positive not null. Fair statement?Nice glenn, for us stat-light posters out here, what does the data tell you?Its a good thing, as it confirms the hypothesis that ON does not provide instantaneous results, as in a square-wave voltage change. Mag heating, frequency and resonance shift all combine (my belief) for variances shown in the points you made above. On the other hand, mag OFF is rather calm and predictable, with mother nature taking over and gently thermal lifting the DUT.@glennfish, attached is the original ft 2d spreadsheet with data channels 2-4 (columns b-d) unhidden. Its in the original file as well, just hidden.
Note on these hidden data channels: The data inputs are unloaded, meaning nothing is attached to them, unlike channel 1 (column a on the spreadsheet), the LDS voltage input. This might be useful in looking at system noise in mag ON/OFF conditions.
While I cannot quantify the randomness, it will be the most variable (very sensitive) since there is no load (resistor) on the inputs. If mag ON imparts system noise, these 3 channels and over 8,100 data points will be the most sensitive to noise and will show it.
Another note. The balanced impedance of channel 1 is 470 ohms. Data on channels 2-4 (columns b-c) are open (infinite impedance by comparison) and are not directly equivalent to channel 1. However general deviation comparisons to mag ON/OFF should give you a relative indication of any system noise attributable to EMI, if present.
Thank you. Now ponder this with me (before I downloaded your data):
1. The data trend overall is a negative slope.
2. You suggested in the last 24 hours that -- the turn-on time to resonance could be seconds
3. So what I did is for each group (on or off), asked, "was the first half of the slope > the 2nd half of the slope?" i.e. was there a slope change from negative to more negative about midpoint in the interval?
Preliminary results
For off groups, that was true 14 out of 47 times
For on groups, that was true 29 out of 47 times
For results, Fisher's exact test for those wanting to learn stats... :)
I have to check my work a few times, and when I do, I'll upload the analysis.
I've confused myself. Would this result be a good thing or a bad thing?
Not sure if the 50% point is the best point to sub-divide, but the ON state variances versus the OFF state variances is a decent way to look at the data subset.
OK spreadsheet with analysis (no VBA)
Sheet: raw.php
raw data and processing
Sheet: Sheet1
summary & results
m1>m2 m1<=m2
Group ON 29 18
Group OFF 14 33
Fisher's exact test, two tailed p = .0035
Fisher's exact test, one tailed p = .0018
stat-light... sounds like a beer :)
OK, there is a very significant difference between the slope behavior for on vs. off, given by the values of p. Close to 1 is bad. Close to 0 is good.
What this indicates is:
If ON, the slope is likely to become more negative during the cycle.
If OFF, the slope is likely to not change or become less negative during the cycle.
examples
define m1 as the slope during the 1st half of the cycle and m2 as the slope during the last half of the cycle.
if m1 = -2 and m2 = -3 then m1>m2 = TRUE
if m1 = -2 and m2 = -1 then m1>m2 = FALSE
I've been OCD like on not calling this effect thrust, and guess I will continue to do so. Without a true understanding of why this happens, it might as well be an attractive or repulsive force. Not 100% comfortable with thrust, so my shorthand is emdrive effect.
Guess a last piece of the puzzle is the open channel data points for relative system noise comparisons betwee on/off states. A quick glance, saw nothing significant in the numbers indicating an EMI induced spike or noise. Let me know if you concur.
Regarding the null test. Aren't we pretty sure that a cylindrical resonator will not thrust? It will heat and do all the other things, but if something is escaping, that something should escape symmetrically, no thrust. If nothing is escaping then still no thrust due to symmetry.
Of course getting the heating rates right may be a little tricky when it comes to comparing to a real EM Drive configuration.
I do think the idea posted much earlier by (I forget who posted it), the idea of two identical frustums, one at each end of a balance beam, would go a long way toward eliminating thermal lift from the data. The idea was to mount both frustums upward, run to steady state then turn one off. Or mount one up, one down and run synchronously, doubling the thrust effect while significantly reducing the lift effect. This one would allow data collection from initial power on of the cold system and still reduce the effect of thermal lift.
Only problem is that it takes two frustums, but rfmwguy can tell us how much difficulty and cost would be involved in building the second identical frustum. And he could likely scope out the required modifications to the test rig as well.
And the difficulty with the word "identical" meaning identical fabrication, feeding, power coupled etc. Not easy. Do-able, but not easy.
H
Thanks again for all your hard work Glenn, it is greatly appreciated. As you said, I could find no correlation in noise to power on, it did seem random to me. I did take the time to do a rough overlay against an image provided by another poster (think it was Joe). Its shows all noise datapoints highly scattered regardless of on or off.Ok, more confirmation of ON cycle changes. Looks like all roads leading to the conclusion that something is definitely happening, i.e. not a null test...positive not null. Fair statement?Nice glenn, for us stat-light posters out here, what does the data tell you?Its a good thing, as it confirms the hypothesis that ON does not provide instantaneous results, as in a square-wave voltage change. Mag heating, frequency and resonance shift all combine (my belief) for variances shown in the points you made above. On the other hand, mag OFF is rather calm and predictable, with mother nature taking over and gently thermal lifting the DUT.@glennfish, attached is the original ft 2d spreadsheet with data channels 2-4 (columns b-d) unhidden. Its in the original file as well, just hidden.
Note on these hidden data channels: The data inputs are unloaded, meaning nothing is attached to them, unlike channel 1 (column a on the spreadsheet), the LDS voltage input. This might be useful in looking at system noise in mag ON/OFF conditions.
While I cannot quantify the randomness, it will be the most variable (very sensitive) since there is no load (resistor) on the inputs. If mag ON imparts system noise, these 3 channels and over 8,100 data points will be the most sensitive to noise and will show it.
Another note. The balanced impedance of channel 1 is 470 ohms. Data on channels 2-4 (columns b-c) are open (infinite impedance by comparison) and are not directly equivalent to channel 1. However general deviation comparisons to mag ON/OFF should give you a relative indication of any system noise attributable to EMI, if present.
Thank you. Now ponder this with me (before I downloaded your data):
1. The data trend overall is a negative slope.
2. You suggested in the last 24 hours that -- the turn-on time to resonance could be seconds
3. So what I did is for each group (on or off), asked, "was the first half of the slope > the 2nd half of the slope?" i.e. was there a slope change from negative to more negative about midpoint in the interval?
Preliminary results
For off groups, that was true 14 out of 47 times
For on groups, that was true 29 out of 47 times
For results, Fisher's exact test for those wanting to learn stats... :)
I have to check my work a few times, and when I do, I'll upload the analysis.
I've confused myself. Would this result be a good thing or a bad thing?
Not sure if the 50% point is the best point to sub-divide, but the ON state variances versus the OFF state variances is a decent way to look at the data subset.
OK spreadsheet with analysis (no VBA)
Sheet: raw.php
raw data and processing
Sheet: Sheet1
summary & results
m1>m2 m1<=m2
Group ON 29 18
Group OFF 14 33
Fisher's exact test, two tailed p = .0035
Fisher's exact test, one tailed p = .0018
stat-light... sounds like a beer :)
OK, there is a very significant difference between the slope behavior for on vs. off, given by the values of p. Close to 1 is bad. Close to 0 is good.
What this indicates is:
If ON, the slope is likely to become more negative during the cycle.
If OFF, the slope is likely to not change or become less negative during the cycle.
examples
define m1 as the slope during the 1st half of the cycle and m2 as the slope during the last half of the cycle.
if m1 = -2 and m2 = -3 then m1>m2 = TRUE
if m1 = -2 and m2 = -1 then m1>m2 = FALSE
I've been OCD like on not calling this effect thrust, and guess I will continue to do so. Without a true understanding of why this happens, it might as well be an attractive or repulsive force. Not 100% comfortable with thrust, so my shorthand is emdrive effect.
Guess a last piece of the puzzle is the open channel data points for relative system noise comparisons betwee on/off states. A quick glance, saw nothing significant in the numbers indicating an EMI induced spike or noise. Let me know if you concur.
Physics isn't my strong suit. Simply put, when power is on, things are different than when power is off. The data supports that.
You have shared your data, and others here have shared their data and analysis. It's fair game for anyone with an internet connection to review, critique, replicate, or ignore.
re the noise numbers in those other channels, I haven't looked extensively but a quick look shows they seem rather random. I did a couple of quick correlation analyses and the rs were in the .00x range. There are only a few discrete values and they look like the lowest possible DAC's deviation from a ground state. They are definitely not correlated with your actual data. I'll look again later, but they seem innocuous.
Regarding the null test. Aren't we pretty sure that a cylindrical resonator will not thrust? It will heat and do all the other things, but if something is escaping, that something should escape symmetrically, no thrust. If nothing is escaping then still no thrust due to symmetry.
Of course getting the heating rates right may be a little tricky when it comes to comparing to a real EM Drive configuration.
I do think the idea posted much earlier by (I forget who posted it), the idea of two identical frustums, one at each end of a balance beam, would go a long way toward eliminating thermal lift from the data. The idea was to mount both frustums upward, run to steady state then turn one off. Or mount one up, one down and run synchronously, doubling the thrust effect while significantly reducing the lift effect. This one would allow data collection from initial power on of the cold system and still reduce the effect of thermal lift.
Only problem is that it takes two frustums, but rfmwguy can tell us how much difficulty and cost would be involved in building the second identical frustum. And he could likely scope out the required modifications to the test rig as well.
And the difficulty with the word "identical" meaning identical fabrication, feeding, power coupled etc. Not easy. Do-able, but not easy.
H
As has been mentioned, identical is good, but not necessary. They just need to be close enough that the second frustum mimics the thermal lift better than a hot plate and also better than nothing. The objective is to counterbalance the thermal effects in order to reduce the unbalanced thermal lift while adding to the the EM drive effect. This should pull the EM drive effect up out of the, now reduced, thermal noise.
QuoteAnd the difficulty with the word "identical" meaning identical fabrication, feeding, power coupled etc. Not easy. Do-able, but not easy.
H
As has been mentioned, identical is good, but not necessary. They just need to be close enough that the second frustum mimics the thermal lift better than a hot plate and also better than nothing. The objective is to counterbalance the thermal effects in order to reduce the unbalanced thermal lift while adding to the the EM drive effect. This should pull the EM drive effect up out of the, now reduced, thermal noise.
True enough - it would definitely allow for a much better signal to noise ratio. But regardless of how well it could be compensated for and used to boost S/N I suspect that the non-identical nature of the two drives would become a new source of doubt for some folks. Definitely worth doing though as I think the better S/N would present a much clearer picture.
Even if I go with a rotating table approach, one set of tests I want to run is frustum v frustum - sort of a mano a mano UFC challenge for propellentless thrust. (sorry - been a long day wading through Medicare paperwork - you haven't lived until you have done that).
H
A while back, somebody noted an experiment that showed thrust by bouncing a laser back and forth. Was this a photonic laser rocket (cool tech, well understood) or did you mean it showed thrust by bouncing a laser off several mirrors and measuring the thrust at the last mirror. If so, can you post a link to the paper or report?
Thanks, had not studied this concept. 5K power increase? Going to have to read his papers closely, also beam confinement seems unlikely, but am open to read up. Trying to think of any energy that would play by these rules. Rf would need guides to contain it or it would instantly scatter. Additive? Now that's interesting.A while back, somebody noted an experiment that showed thrust by bouncing a laser back and forth. Was this a photonic laser rocket (cool tech, well understood) or did you mean it showed thrust by bouncing a laser off several mirrors and measuring the thrust at the last mirror. If so, can you post a link to the paper or report?
That was probably me. I have suspected Since blundering across David Bae's work most of a year ago that it contains part of the key as to what is going on with the EM Drive.
Bae's website:
http://ykbcorp.com/tech_precFormation.html
Article:
http://www.centauri-dreams.org/?p=29341
Test result from May 2015:
http://www.popularmechanics.com/space/a15545/photonic-laser-thrust-space-engine/
Links to papers:
http://www.thelivingmoon.com/41pegasus/02files/PLT_Photonic_Laser_Thruster_01.html
What gets me here is this 'photon recycling scheme' produces output power on the order of 5000 times that of the input power - which as I understand such things, is either 'free energy territory' or dang close to it. Yet, the effects are well supported by laboratory work, and supposedly COE is not violated.
Which leads me to wonder: if the EM Drive is somehow doing something similar to Bae's device, would that constitute a COE violation?
Where is our friend Rodal? It seems he has been quiet for half a month.
What gets me here is this 'photon recycling scheme' produces output power on the order of 5000 times that of the input power - which as I understand such things, is either 'free energy territory' or dang close to it. Yet, the effects are well supported by laboratory work, and supposedly COE is not violated.
Which leads me to wonder: if the EM Drive is somehow doing something similar to Bae's device, would that constitute a COE violation?
Where is our friend Rodal? It seems he has been quiet for half a month.
I believe he is around just in lurking mode. Dr. Rodal follows EmDrive debate from the start, so in my opinion he also needs some time to focus on different things and some rest from this debate :). I also believe we may see many folks returing once we see data from NASA EW by the end of this year.
Only rumors from last year that new testing will be done by this past summers end. Lets cross our fingers.Where is our friend Rodal? It seems he has been quiet for half a month.
I believe he is around just in lurking mode. Dr. Rodal follows EmDrive debate from the start, so in my opinion he also needs some time to focus on different things and some rest from this debate :). I also believe we may see many folks returing once we see data from NASA EW by the end of this year.
Can we be so sure of hearing anything from NASA EW within that timeframe, I'm not after past events?
Under the auspice of NIAC/NASA, the author successfully demonstrated the proof-of-concept of a
PLT. [3,16] In this demonstration, a PLT was built from off-the-shelf optical components and a YAG
gain medium, and the maximum amplified photon thrust achieved was 35 μN for a laser output of 1.7 W
with the use of a HR mirror with a 0.99967 reflectance. This performance corresponds to an apparent
photon thrust amplification factor of ~3,000. More importantly, in the experimental demonstration, the
author accidentally discovered that the PLT cavity is highly stable against the mirror motion and
misalignment unlike passive optical cavities. In fact, in the demonstration experiment by the author, the
full resonance mode of the PLT was discovered to maintain even when one of the HR mirror was held,
moved, and tilted by a hand to the author’s surprise. In a more systematic experiment, the PLT cavity
was systematically demonstrated to be highly stable against tilting, vibration and motion of mirrors.
Subsequent theoretical analysis by the author showed that PLT can indeed be used for propulsion
applications, and proposed Photonic Laser Propulsion (PLP), the propulsion with PLT. [15] The reason
for the observed stability results from that in the active optical cavities for PLT and PLP the laser gain
medium dynamically adapts to the changes in the cavity parameters, such as mirror motion, vibration and
tilting, which does not exist in the passive optical cavities.
Dr. Rodel, the troops would like a "I'm here and fine". Believe it when I say, we all miss your posts. But I understand when other life issues (maybe by making a living) take front stage.
Our best to you.
Shell
Dr. Rodel, the troops would like a "I'm here and fine". Believe it when I say, we all miss your posts. But I understand when other life issues (maybe by making a living) take front stage.
Our best to you.
Shell
I spoke with him yesterday. He's here. He's fine.
I've seen a few "like"s he made on some topics in the past 12 days, so Dr Rodal is still following the forum...
Consequently, I don't think there is a medical problem, like it was the case with TT going offline...
It just adds a bit more mystery... :o... certainly when you realize he has been posting several times per day ever since this topic started...
Doc, ya had me scared for a second, just when my experiment went into hibernation after successful testing. I was hoping it had not inadvertedly beam you off-planet throught some sort of spacetime collapse or something ;)Dr. Rodel, the troops would like a "I'm here and fine". Believe it when I say, we all miss your posts. But I understand when other life issues (maybe by making a living) take front stage.
Our best to you.
Shell
I spoke with him yesterday. He's here. He's fine.
Hum, plugging along when I should be doing something else. Here is a visualization of a https://en.wikipedia.org/wiki/Whispering-gallery_wave (https://en.wikipedia.org/wiki/Whispering-gallery_wave) resonator. I can't help but notice that the wave pattern looks very much like the "nodules" that appeared on the MEEP output of the big base of CE-3.
For an EMDrive, I wonder what would happen if you put a microwave gain media and a pump inside the cavity. The gain media could either be a gas or a solid state media. I wonder how big you could get a solid state media. While I've read the almost all solid state gain media for a Maser need cryogenic cooling to work, if you have a superconductor on one end of the cavity you already need that cooling.
Can I jump up and down a couple times and say that I think Bae's observation is important.
Hi everyone, I've been away for a while, and I have tried to catch up but there's just so much to read.You understand the situation well. My frustum was a collaboration of people here giving me specs on a design not using a dielectric. I believe it worked good enough to convince me to design and build next year.
What is that general opinion about a high Q being necessary for the emdrive to work efficiently? I haven't seen much about going to the extremes of high-Q, such as superconducting cavities at cryogenic temperatures. I understand that such a cool temperature makes test conditions more difficult, but if high Q will result in greater efficiency, isn't this worth trying? Also, magnesium diboride shouldn't be too hard to form (type II, cuprate superconductors might be quite a bit more of a chore). One thing, though, that concerns me: with such a high Q, the bandwidth would be very narrow, and that unless the microwave source is extremely well matched to the cavity's resonance, it will require tuning. From my experience with tuning high-Q antennas in amateur radio, I know that it is possible to just slide right past the point of resonance if tuning is too coarse. One solution to the problem might be to temporarily drop the Q, just so it's easier to find the proper range, and then gradually tighten it in fine tuning. Though I have a hunch that the highest-Q, available from superconducting cavities, might create such a shape bandwidth that none of our signal sources are going to be precise and stable enough to stay tuned to it, so we might have to always artificially drop the Q from what a superconducting cavity might be capable of. I haven't put this to the test, nor have I even done any numerical reasoning on the idea, but I think it's worth mentioning.
A reddit user, Kasuha, has created a very interesting spreadsheet on NSF-1701 FT2D (full test). His interpretation of the data was all noise, but without understanding the test stand particulars, he has actually shown a definitive negative drop in both speed and acceleration (of the frustum end of the balance beam) as soon as the magnetron is powered ON (those traces are Red).
Note they almost always follow the 11 second mag OFF (Blue) condition where speed and acceleration were on the rise.
Maybe this is another way to separate out the EmDrive Effect from the thermal lift. You can see lift bubbling up in between test runs when mag is OFF. The frequency and amplitide of the trace in this region is quite different that the ON/OFF period. Remember, there is Doc's oil dampening system on the beam so this is all thermal lift variations (in the Blue-only regions).
Regardless, I appreciate his work and appears to me that in 75% or more of the ON/OFF cycles, mag ON forces a drop in speed and acceleration.
He shared this openly and if this helps future experimenters, he is please to do so.
Sometimes you need a day, I took it today. I live in the Colorado Rockies and this time of year is afire with the leaves changing and good friends you haven't visited for awhile to simply visit. Dusted off the old 65 Pontiac and did just that. Got away from the building the EMDrive and test bed and enjoyed what little there is left of warm weather.
No new news today from the build, sorry... but the old gal building it feels much better!
Shell
OMG... I woke up this morning thinking it was Monday. Point on.Sometimes you need a day, I took it today. I live in the Colorado Rockies and this time of year is afire with the leaves changing and good friends you haven't visited for awhile to simply visit. Dusted off the old 65 Pontiac and did just that. Got away from the building the EMDrive and test bed and enjoyed what little there is left of warm weather.
No new news today from the build, sorry... but the old gal building it feels much better!
Shell
Good on you! Excellent way to recharge the batteries.
My father passed on some words of wisdom years ago concerning retirement which I am just now finding out the value of. He said - "Retirement is every day. Its continuous, no weekends or holidays. So every once in a while you have to make sure you take a day off."
I find - when I am not sure what day of the week it is - its time for a day off.
H.
I told Kasuha that I would have never thought of speed and acceleration in a balance beam measurement, only straight line linear. But, if what I think is happening, the deceleration during ON is a good way to carve out data from lift.A reddit user, Kasuha, has created a very interesting spreadsheet on NSF-1701 FT2D (full test). His interpretation of the data was all noise, but without understanding the test stand particulars, he has actually shown a definitive negative drop in both speed and acceleration (of the frustum end of the balance beam) as soon as the magnetron is powered ON (those traces are Red).
Note they almost always follow the 11 second mag OFF (Blue) condition where speed and acceleration were on the rise.
Maybe this is another way to separate out the EmDrive Effect from the thermal lift. You can see lift bubbling up in between test runs when mag is OFF. The frequency and amplitide of the trace in this region is quite different that the ON/OFF period. Remember, there is Doc's oil dampening system on the beam so this is all thermal lift variations (in the Blue-only regions).
Regardless, I appreciate his work and appears to me that in 75% or more of the ON/OFF cycles, mag ON forces a drop in speed and acceleration.
He shared this openly and if this helps future experimenters, he is please to do so.
Looked over the spreadsheet and charts for a bit tonight - I think you are on to something in your interpretation. Concur that at least 75% of ON/OFF appear to have SOMETHING different happening in the ON portion.
I'm rusty on my statistics but I think there are some noise or noise randomness metrics that might be applied comparing between OFF times ON/OFF time. Maybe someone more up on the magic of stat analy ( and probably more awake) can do something definitive with this beyond the just visual interpretation.
But kudos to Kashua !!! nice piece of work. And I there is much here to glean for future builds - I will examine WRT my plans tomorrow after sleep.
H.
I told Kasuha that I would have never thought of speed and acceleration in a balance beam measurement, only straight line linear. But, if what I think is happening, the deceleration during ON is a good way to carve out data from lift.A reddit user, Kasuha, has created a very interesting spreadsheet on NSF-1701 FT2D (full test). His interpretation of the data was all noise, but without understanding the test stand particulars, he has actually shown a definitive negative drop in both speed and acceleration (of the frustum end of the balance beam) as soon as the magnetron is powered ON (those traces are Red).
Note they almost always follow the 11 second mag OFF (Blue) condition where speed and acceleration were on the rise.
Maybe this is another way to separate out the EmDrive Effect from the thermal lift. You can see lift bubbling up in between test runs when mag is OFF. The frequency and amplitide of the trace in this region is quite different that the ON/OFF period. Remember, there is Doc's oil dampening system on the beam so this is all thermal lift variations (in the Blue-only regions).
Regardless, I appreciate his work and appears to me that in 75% or more of the ON/OFF cycles, mag ON forces a drop in speed and acceleration.
He shared this openly and if this helps future experimenters, he is please to do so.
Looked over the spreadsheet and charts for a bit tonight - I think you are on to something in your interpretation. Concur that at least 75% of ON/OFF appear to have SOMETHING different happening in the ON portion.
I'm rusty on my statistics but I think there are some noise or noise randomness metrics that might be applied comparing between OFF times ON/OFF time. Maybe someone more up on the magic of stat analy ( and probably more awake) can do something definitive with this beyond the just visual interpretation.
But kudos to Kashua !!! nice piece of work. And I there is much here to glean for future builds - I will examine WRT my plans tomorrow after sleep.
H.
However, a more precise clock will be needed for better resolution...will ponder that for several weeks I'm sure.
As has been mentioned, identical is good, but not necessary. They just need to be close enough that the second frustum mimics the thermal lift better than a hot plate and also better than nothing. The objective is to counterbalance the thermal effects in order to reduce the unbalanced thermal lift while adding to the the EM drive effect. This should pull the EM drive effect up out of the, now reduced, thermal noise.Most of the trouble with thermal dissipation comes from its natural convective heat transfer mode which entails air movement which has a random mechanical effect on the test set up. If we could reinforce the conductive and radiative modes of thermal dissipation, we should reduce the effects of convection and their random features.
Hi everyone, I've been away for a while, and I have tried to catch up but there's just so much to read.From DYIer perspective.
What is that general opinion about a high Q being necessary for the emdrive to work efficiently? I haven't seen much about going to the extremes of high-Q, such as superconducting cavities at cryogenic temperatures. I understand that such a cool temperature makes test conditions more difficult, but if high Q will result in greater efficiency, isn't this worth trying? Also, magnesium diboride shouldn't be too hard to form (type II, cuprate superconductors might be quite a bit more of a chore). One thing, though, that concerns me: with such a high Q, the bandwidth would be very narrow, and that unless the microwave source is extremely well matched to the cavity's resonance, it will require tuning. From my experience with tuning high-Q antennas in amateur radio, I know that it is possible to just slide right past the point of resonance if tuning is too coarse. One solution to the problem might be to temporarily drop the Q, just so it's easier to find the proper range, and then gradually tighten it in fine tuning. Though I have a hunch that the highest-Q, available from superconducting cavities, might create such a shape bandwidth that none of our signal sources are going to be precise and stable enough to stay tuned to it, so we might have to always artificially drop the Q from what a superconducting cavity might be capable of. I haven't put this to the test, nor have I even done any numerical reasoning on the idea, but I think it's worth mentioning.
A reddit user, Kasuha, has created a very interesting spreadsheet on NSF-1701 FT2D (full test). His interpretation of the data was all noise, but without understanding the test stand particulars, he has actually shown a definitive negative drop in both speed and acceleration (of the frustum end of the balance beam) as soon as the magnetron is powered ON (those traces are Red).
Note they almost always follow the 11 second mag OFF (Blue) condition where speed and acceleration were on the rise.
Maybe this is another way to separate out the EmDrive Effect from the thermal lift. You can see lift bubbling up in between test runs when mag is OFF. The frequency and amplitide of the trace in this region is quite different that the ON/OFF period. Remember, there is Doc's oil dampening system on the beam so this is all thermal lift variations (in the Blue-only regions).
Regardless, I appreciate his work and appears to me that in 75% or more of the ON/OFF cycles, mag ON forces a drop in speed and acceleration.
He shared this openly and if this helps future experimenters, he is please to do so.
A reddit user, Kasuha, has created a very interesting spreadsheet on NSF-1701 FT2D (full test). His interpretation of the data was all noise, but without understanding the test stand particulars, he has actually shown a definitive negative drop in both speed and acceleration (of the frustum end of the balance beam) as soon as the magnetron is powered ON (those traces are Red).
Note they almost always follow the 11 second mag OFF (Blue) condition where speed and acceleration were on the rise.
Maybe this is another way to separate out the EmDrive Effect from the thermal lift. You can see lift bubbling up in between test runs when mag is OFF. The frequency and amplitide of the trace in this region is quite different that the ON/OFF period. Remember, there is Doc's oil dampening system on the beam so this is all thermal lift variations (in the Blue-only regions).
Regardless, I appreciate his work and appears to me that in 75% or more of the ON/OFF cycles, mag ON forces a drop in speed and acceleration.
He shared this openly and if this helps future experimenters, he is please to do so.
I'm not sure how to interpret his results. His calculated values include data from OFF regions, when ON, and ON regions, when OFF.
It was a bit difficult from me as well, although I think he might be on to something about the acceleration analysis. Thermal lift will want to stabilize at a certain velocity and a power on condition should cause that velocity to change. Not sure how to set up the delta V/delta T formulas. Unfortunately the time stamp resolution is only 1 second, so rather poor resolution for a proper speed/velocity reading.A reddit user, Kasuha, has created a very interesting spreadsheet on NSF-1701 FT2D (full test). His interpretation of the data was all noise, but without understanding the test stand particulars, he has actually shown a definitive negative drop in both speed and acceleration (of the frustum end of the balance beam) as soon as the magnetron is powered ON (those traces are Red).
Note they almost always follow the 11 second mag OFF (Blue) condition where speed and acceleration were on the rise.
Maybe this is another way to separate out the EmDrive Effect from the thermal lift. You can see lift bubbling up in between test runs when mag is OFF. The frequency and amplitide of the trace in this region is quite different that the ON/OFF period. Remember, there is Doc's oil dampening system on the beam so this is all thermal lift variations (in the Blue-only regions).
Regardless, I appreciate his work and appears to me that in 75% or more of the ON/OFF cycles, mag ON forces a drop in speed and acceleration.
He shared this openly and if this helps future experimenters, he is please to do so.
I'm not sure how to interpret his results. His calculated values include data from OFF regions, when ON, and ON regions, when OFF.
It was a bit difficult from me as well, although I think he might be on to something about the acceleration analysis. Thermal lift will want to stabilize at a certain velocity and a power on condition should cause that velocity to change. Not sure how to set up the delta V/delta T formulas. Unfortunately the time stamp resolution is only 1 second, so rather poor resolution for a proper speed/velocity reading.A reddit user, Kasuha, has created a very interesting spreadsheet on NSF-1701 FT2D (full test). His interpretation of the data was all noise, but without understanding the test stand particulars, he has actually shown a definitive negative drop in both speed and acceleration (of the frustum end of the balance beam) as soon as the magnetron is powered ON (those traces are Red).
Note they almost always follow the 11 second mag OFF (Blue) condition where speed and acceleration were on the rise.
Maybe this is another way to separate out the EmDrive Effect from the thermal lift. You can see lift bubbling up in between test runs when mag is OFF. The frequency and amplitide of the trace in this region is quite different that the ON/OFF period. Remember, there is Doc's oil dampening system on the beam so this is all thermal lift variations (in the Blue-only regions).
Regardless, I appreciate his work and appears to me that in 75% or more of the ON/OFF cycles, mag ON forces a drop in speed and acceleration.
He shared this openly and if this helps future experimenters, he is please to do so.
I'm not sure how to interpret his results. His calculated values include data from OFF regions, when ON, and ON regions, when OFF.
I ask :DIt was a bit difficult from me as well, although I think he might be on to something about the acceleration analysis. Thermal lift will want to stabilize at a certain velocity and a power on condition should cause that velocity to change. Not sure how to set up the delta V/delta T formulas. Unfortunately the time stamp resolution is only 1 second, so rather poor resolution for a proper speed/velocity reading.A reddit user, Kasuha, has created a very interesting spreadsheet on NSF-1701 FT2D (full test). His interpretation of the data was all noise, but without understanding the test stand particulars, he has actually shown a definitive negative drop in both speed and acceleration (of the frustum end of the balance beam) as soon as the magnetron is powered ON (those traces are Red).
Note they almost always follow the 11 second mag OFF (Blue) condition where speed and acceleration were on the rise.
Maybe this is another way to separate out the EmDrive Effect from the thermal lift. You can see lift bubbling up in between test runs when mag is OFF. The frequency and amplitide of the trace in this region is quite different that the ON/OFF period. Remember, there is Doc's oil dampening system on the beam so this is all thermal lift variations (in the Blue-only regions).
Regardless, I appreciate his work and appears to me that in 75% or more of the ON/OFF cycles, mag ON forces a drop in speed and acceleration.
He shared this openly and if this helps future experimenters, he is please to do so.
I'm not sure how to interpret his results. His calculated values include data from OFF regions, when ON, and ON regions, when OFF.
Well just for jollies, I decided to look at the differences. Even if I don't like his spreadsheet, it is an interesting idea. I did some visual basic to do the following:
1. find the difference between two measurements (v) (didn't use the timestamp)
2. for each group of on or off, find the average (v) for that group
3. calculate the number of times adjacent Voff>Von and adjacent Von>=Voff
Here are the results for the 47 pairs (groups)
Voff>Von: 16
Von>=Voff: 31
The actual is about 66%, RFMWGUY was off by 9%. Better than government contractors for sure. :)
Let's make someone on Reddit do the stats. :)
I'll upload the spreadsheet & VBA if anyone asks.
I ask :DIt was a bit difficult from me as well, although I think he might be on to something about the acceleration analysis. Thermal lift will want to stabilize at a certain velocity and a power on condition should cause that velocity to change. Not sure how to set up the delta V/delta T formulas. Unfortunately the time stamp resolution is only 1 second, so rather poor resolution for a proper speed/velocity reading.A reddit user, Kasuha, has created a very interesting spreadsheet on NSF-1701 FT2D (full test). His interpretation of the data was all noise, but without understanding the test stand particulars, he has actually shown a definitive negative drop in both speed and acceleration (of the frustum end of the balance beam) as soon as the magnetron is powered ON (those traces are Red).
Note they almost always follow the 11 second mag OFF (Blue) condition where speed and acceleration were on the rise.
Maybe this is another way to separate out the EmDrive Effect from the thermal lift. You can see lift bubbling up in between test runs when mag is OFF. The frequency and amplitide of the trace in this region is quite different that the ON/OFF period. Remember, there is Doc's oil dampening system on the beam so this is all thermal lift variations (in the Blue-only regions).
Regardless, I appreciate his work and appears to me that in 75% or more of the ON/OFF cycles, mag ON forces a drop in speed and acceleration.
He shared this openly and if this helps future experimenters, he is please to do so.
I'm not sure how to interpret his results. His calculated values include data from OFF regions, when ON, and ON regions, when OFF.
Well just for jollies, I decided to look at the differences. Even if I don't like his spreadsheet, it is an interesting idea. I did some visual basic to do the following:
1. find the difference between two measurements (v) (didn't use the timestamp)
2. for each group of on or off, find the average (v) for that group
3. calculate the number of times adjacent Voff>Von and adjacent Von>=Voff
Here are the results for the 47 pairs (groups)
Voff>Von: 16
Von>=Voff: 31
The actual is about 66%, RFMWGUY was off by 9%. Better than government contractors for sure. :)
Let's make someone on Reddit do the stats. :)
I'll upload the spreadsheet & VBA if anyone asks.
Hi everyone, I've been away for a while, and I have tried to catch up but there's just so much to read.From DYIer perspective.
What is that general opinion about a high Q being necessary for the emdrive to work efficiently? I haven't seen much about going to the extremes of high-Q, such as superconducting cavities at cryogenic temperatures. I understand that such a cool temperature makes test conditions more difficult, but if high Q will result in greater efficiency, isn't this worth trying? Also, magnesium diboride shouldn't be too hard to form (type II, cuprate superconductors might be quite a bit more of a chore). One thing, though, that concerns me: with such a high Q, the bandwidth would be very narrow, and that unless the microwave source is extremely well matched to the cavity's resonance, it will require tuning. From my experience with tuning high-Q antennas in amateur radio, I know that it is possible to just slide right past the point of resonance if tuning is too coarse. One solution to the problem might be to temporarily drop the Q, just so it's easier to find the proper range, and then gradually tighten it in fine tuning. Though I have a hunch that the highest-Q, available from superconducting cavities, might create such a shape bandwidth that none of our signal sources are going to be precise and stable enough to stay tuned to it, so we might have to always artificially drop the Q from what a superconducting cavity might be capable of. I haven't put this to the test, nor have I even done any numerical reasoning on the idea, but I think it's worth mentioning.
The Thermal Expansion Coefficient for copper is: 0.000017 (m/moC)
http://hyperphysics.phy-astr.gsu.edu/hbase/tables/thexp.html#c1
This TEC becomes a issue in the changing of the cavity length but also the warping of the hot zones within the copper at the modes points. If we were smarter we could build it of quartz (flashed with silver and gold) which is 28x less or some other 0o TEC material, but that becomes something expensive a DYier can't do.
So a DYier can do a couple things, go low power which is tough to get any readings or go higher power and try to negate by design the issue of TEC. I think the best of both worlds would be negating the TEC thru design (I've tried to do) ... and make it superconducting but I'm going for up to 2 KW into the frustum.
Right now I'm shooting for design control of the TEC and producing a clean RF through a modified magnetron inverter and removing the hot magnetron away from the frustum and feeding the RF into the frustum via antenna or waveguide. These designs have given a very high Q but it is to be seen if I can keep the higher Qs in a real world operation.
Simple thought, lower Qs mean the incoming RF signal is absorbed into the frustum and turned into simply generating heat. Unless I want to drive this with a megawatt(s) klystron turning the frustum into a white hot effervescent accelerating stream of gas, that might give me acceleration but it's outside of the box and a simple rocket then.
The most likely explanation is that I have made an error in programming my spreadsheet somewhere. I originally thought the error related to a measuring error in one of the constants. Then I started getting redshift of 0.6 htz, that implies a fairly large measurement error somewhere. Since I'm pulling the photon rocket equations from published literature, the error has to be in how I'm calculating the redshift (possibly in the number of photons). Anyone know what I should be doing to get redshift as an integer?
Good morning. I have been lurking and observing various emdrive communities for quite a long time. Mostly, I wonder and read, hoping people will talk about what I'm wondering about. I tend not to ask questions because my ignorance of the subject matter is profound, but for the last few days, my curiosity has really been a source of frustration.Welcome to the forum. :)
What is the source of the resonance in the resonance cavity? Is the copper acting as a mirror for the microwaves, or is there some mechanism at work other than reflection?
If it is acting as a mirror, then I have some questions about an unrelated set of experiments I read about some time ago. A group of researchers apparently made some kind of microwave mirror out of an "electrical short circuit", that they were able to vibrate over a nano-meter at 0.25c. Doing so coaxed virtual photons into becoming actual photons, through some theorized property of the Casimir effect. I do not fully understand what they mean by the vague term in quotes, but it seems curious regardless.
Given that the vibrations they reported are 0.25c, does this mean the surface of their microwave mirror is not a physical surface but rather some kind of field?
If the surface of their microwave mirror is not a physical surface, would it be possible to create a non-physical microwave mirror surface in an emdrive, and if so, would there be any worthwhile benefits to doing so such as greater control of resonance, a more flexible/dynamic shape, mitigation of thermal deformation, ruling out potential error sources, etc?
In either case, if an emdrive's current copper frustum is acting as a microwave mirror, is it possible that resonance is somehow creating a similar nano-scale vibration at relativistic speeds, coaxing virtual particles into becoming real particles? If so, what would be the implications for thrust signals?
I am a software developer and not a scientist or engineer, so I am fully aware that these questions are likely quite misguided. Still, I can only contain my curiosity for so long, and I figure there's little harm in wondering aloud once in a while. Thank you for all the great reading over the months.
I have not read any actual papers about it, just a series of articles reporting on it.May be you mean this? http://arxiv.org/abs/1105.4714
You can find a lot of links here:
https://www.google.com/search?q=mirror+virtual+photon+to+actual+photon (https://www.google.com/search?q=mirror+virtual+photon+to+actual+photon)
For light, one hertz is one plank constant.
That seems consistent with what I read, yes. :-)OK i am reading the paper...
That seems consistent with what I read, yes. :-)OK i am reading the paper...
and i find the following:
"If we consider the literal experiment of moving a physical mirror near the speed light,
we quickly see that this experiment is not feasible. Braggio et al. considered[6] the case of moving a typical microwave mirror in an oscillating motion at a frequency of 2 GHz with a displacement of 1 nm. This produces a velocity ratio of only
v/c~10^-7 with an expected photon production rate of approximately 1 per day. Nevertheless, it requires an input of mechanical power of 100 MW while, at the same time, the system would need to be cooled to ~20 mK to ensure that the EM feld is in its vacuum state...."
The actual experiments (also in vacuum) work at room temperature.
Nevertheless its a very interesting paper!
Hi everyone, I've been away for a while, and I have tried to catch up but there's just so much to read.From DYIer perspective.
What is that general opinion about a high Q being necessary for the emdrive to work efficiently? I haven't seen much about going to the extremes of high-Q, such as superconducting cavities at cryogenic temperatures. I understand that such a cool temperature makes test conditions more difficult, but if high Q will result in greater efficiency, isn't this worth trying? Also, magnesium diboride shouldn't be too hard to form (type II, cuprate superconductors might be quite a bit more of a chore). One thing, though, that concerns me: with such a high Q, the bandwidth would be very narrow, and that unless the microwave source is extremely well matched to the cavity's resonance, it will require tuning. From my experience with tuning high-Q antennas in amateur radio, I know that it is possible to just slide right past the point of resonance if tuning is too coarse. One solution to the problem might be to temporarily drop the Q, just so it's easier to find the proper range, and then gradually tighten it in fine tuning. Though I have a hunch that the highest-Q, available from superconducting cavities, might create such a shape bandwidth that none of our signal sources are going to be precise and stable enough to stay tuned to it, so we might have to always artificially drop the Q from what a superconducting cavity might be capable of. I haven't put this to the test, nor have I even done any numerical reasoning on the idea, but I think it's worth mentioning.
The Thermal Expansion Coefficient for copper is: 0.000017 (m/moC)
http://hyperphysics.phy-astr.gsu.edu/hbase/tables/thexp.html#c1
This TEC becomes a issue in the changing of the cavity length but also the warping of the hot zones within the copper at the modes points. If we were smarter we could build it of quartz (flashed with silver and gold) which is 28x less or some other 0o TEC material, but that becomes something expensive a DYier can't do.
So a DYier can do a couple things, go low power which is tough to get any readings or go higher power and try to negate by design the issue of TEC. I think the best of both worlds would be negating the TEC thru design (I've tried to do) ... and make it superconducting but I'm going for up to 2 KW into the frustum.
Right now I'm shooting for design control of the TEC and producing a clean RF through a modified magnetron inverter and removing the hot magnetron away from the frustum and feeding the RF into the frustum via antenna or waveguide. These designs have given a very high Q but it is to be seen if I can keep the higher Qs in a real world operation.
Simple thought, lower Qs mean the incoming RF signal is absorbed into the frustum and turned into simply generating heat. Unless I want to drive this with a megawatt(s) klystron turning the frustum into a white hot effervescent accelerating stream of gas, that might give me acceleration but it's outside of the box and a simple rocket then.
MgB2 electroplated onto SiC would be pretty stable at low cryogenic temp, though. Still not easy to do. Magnetrons have messy spectrum but you can clean them up with a PLL.
It seems to me that a high-Q cavity is necessary for high power, otherwise there's going to be a lot of heat, possibly leading to mechanical failure/explosion. But unless that match is good, Q will be horribly high, leading to heat, and in the case of a superconductor, thermal runaway to disaster. So, a good design might have signal generator of adjustable power and frequency (but a good, clean sine wave), and the cavity be superconducting high-Q but have a tunable Q. At startup, power is low and Q is low. the frequency of the signal generator is tuned to the middle of resonance, then the Q is increased and power increased, and the cycle repeated until emdrive effect is strong.
This requires that the adjustment of the Q is stable, and that it be protected against thermal runaway.
If some of the about language/thought seems unclear, please excuse me, I haven't yet had my coffee
Heat caused by the MW energy is everywhere in such high power experiments, the question is where it is:Hi everyone, I've been away for a while, and I have tried to catch up but there's just so much to read.From DYIer perspective.
What is that general opinion about a high Q being necessary for the emdrive to work efficiently? I haven't seen much about going to the extremes of high-Q, such as superconducting cavities at cryogenic temperatures. I understand that such a cool temperature makes test conditions more difficult, but if high Q will result in greater efficiency, isn't this worth trying? Also, magnesium diboride shouldn't be too hard to form (type II, cuprate superconductors might be quite a bit more of a chore). One thing, though, that concerns me: with such a high Q, the bandwidth would be very narrow, and that unless the microwave source is extremely well matched to the cavity's resonance, it will require tuning. From my experience with tuning high-Q antennas in amateur radio, I know that it is possible to just slide right past the point of resonance if tuning is too coarse. One solution to the problem might be to temporarily drop the Q, just so it's easier to find the proper range, and then gradually tighten it in fine tuning. Though I have a hunch that the highest-Q, available from superconducting cavities, might create such a shape bandwidth that none of our signal sources are going to be precise and stable enough to stay tuned to it, so we might have to always artificially drop the Q from what a superconducting cavity might be capable of. I haven't put this to the test, nor have I even done any numerical reasoning on the idea, but I think it's worth mentioning.
The Thermal Expansion Coefficient for copper is: 0.000017 (m/moC)
http://hyperphysics.phy-astr.gsu.edu/hbase/tables/thexp.html#c1
This TEC becomes a issue in the changing of the cavity length but also the warping of the hot zones within the copper at the modes points. If we were smarter we could build it of quartz (flashed with silver and gold) which is 28x less or some other 0o TEC material, but that becomes something expensive a DYier can't do.
So a DYier can do a couple things, go low power which is tough to get any readings or go higher power and try to negate by design the issue of TEC. I think the best of both worlds would be negating the TEC thru design (I've tried to do) ... and make it superconducting but I'm going for up to 2 KW into the frustum.
Right now I'm shooting for design control of the TEC and producing a clean RF through a modified magnetron inverter and removing the hot magnetron away from the frustum and feeding the RF into the frustum via antenna or waveguide. These designs have given a very high Q but it is to be seen if I can keep the higher Qs in a real world operation.
Simple thought, lower Qs mean the incoming RF signal is absorbed into the frustum and turned into simply generating heat. Unless I want to drive this with a megawatt(s) klystron turning the frustum into a white hot effervescent accelerating stream of gas, that might give me acceleration but it's outside of the box and a simple rocket then.
MgB2 electroplated onto SiC would be pretty stable at low cryogenic temp, though. Still not easy to do. Magnetrons have messy spectrum but you can clean them up with a PLL.
It seems to me that a high-Q cavity is necessary for high power, otherwise there's going to be a lot of heat, possibly leading to mechanical failure/explosion. But unless that match is good, Q will be horribly high, leading to heat, and in the case of a superconductor, thermal runaway to disaster. So, a good design might have signal generator of adjustable power and frequency (but a good, clean sine wave), and the cavity be superconducting high-Q but have a tunable Q. At startup, power is low and Q is low. the frequency of the signal generator is tuned to the middle of resonance, then the Q is increased and power increased, and the cycle repeated until emdrive effect is strong.
This requires that the adjustment of the Q is stable, and that it be protected against thermal runaway.
If some of the about language/thought seems unclear, please excuse me, I haven't yet had my coffee
"It seems to me that a high-Q cavity is necessary for high power, otherwise there's going to be a lot of heat, possibly leading to mechanical failure/explosion. "
Yes, that's what I said.
There are three ways one can assure the maintenance of a high Q system and this is true for room temperature drives and superconducting.
First, build it out of a nearly 0 degee TEC material. There are plenty of them to choose from. All are expensive and not easy to make but they can be done.
Second. As the frustum heats up and deforms changing the resonate window, shift the incoming frequency to center it again. It will still heat up and deform the frustum in the growth of the side walls and in the deformation of heated zones when generated modes are made. It is unavoidable.
Third. Knowing the frustum is going to heat up and thermally expand regardless of where you shift the incoming frequency to match. The frustum assures in it's operation that the wave formed modes will collapse and or the different modes will interact with each other. That interaction and or collapse when it happens in a destructive way creates heat. It is in it's design nature to heat up. Design for the thermal expansion.
What I've done in this design is realize that the frustum will continue to heat as long as RF is pumped into the chamber, even when the incoming signal is phased locked to Q.
I capture the two end plates with a quartz rod between running through the center. Quartz is virtually transparent to microwaves and has a very low TEC for growth. (see pic) The large plate is secured to the sidewall with the quartz rod freely running through it and attaches to the small endplate which the tuning micrometer can change the resonate length by sliding the small plate in and out of the tubular tuning chamber at the top. (see pic).
The frustum is going to heat up, the sidewalls are going to expand and the endplates are going to want to deform from mode generation. Capture the endplates setting the resonance distance and secure the copper endplates onto a ceramic plate keeping them from warping. The copper side wall can slide past the small endplate that has a sliding gasket of beryllium copper. Let it expand as its nature to do so but keep the resonance distance between the plates within the magnetron's RF envelope. This can be used at a future date along with a RF locked Q and do it at room temperature.
Shell
I'm killing 2 birds with one stone. (old saying) I'm building a dual waveguide injector system and the same frustum will allow the antennas in the small end plate.Heat caused by the MW energy is everywhere in such high power experiments, the question is where it is:
@ low Q the power will be reflected and heats the magnetron/source
@ matched resonance frequency it will heat the frustum
point ::)
But i think your tunable design is great for this experiments, also the modified loop antenna(my favorite design for the TE01p mode)! You know with kind of antenna think about ;) :)
Dual injectors... see meep animation attached.
Shell
{snip}
Here's the problem, I said that each bounce wants to redshift the light by "about" so many hertz. For light, one hertz is one plank constant. The plank constant is the smallest possible unit of energy in the Universe. It has to be an integer.
{snip}
It would appear it does propagate to the small end. As far as the thermal gradient I would assume it would follow the highest energy modes. Don't forget that what you're seeing here is happening only during one cycle of 2.47 billion in one second. The copper will not thermally conduct patterns looking like this at those speeds.
Dual injectors... see meep animation attached.
Shell
Dumb questions as a data miner:
1. Does that animated gif show a field propogation from one end to the other?
2. If so, is there a thermal gradient that follows that propogation?
3. If so, on the outside of the wall, would there be a comparable thermal gradient that also propogates?
Shell:This is why I bonded the copper sheet onto the Ceramic plates, ceramic is relatively unaffected by the thermal expansion. The bottom plate is locked on to the sidewalls of the frustum and the top plate is secured to the quartz rod and from the side of the small plate to the side of the top tune chamber is a flexible beryllium gasket that allows it to slide freely for tuning and also the copper walls of the frustum to slide past it as they expand.
Thinking about your sliding end plate and the effect of uneven heating. Since expansion of copper is linear with change in temperature, if both the small end circumference of the frustum and the diameter of the small end plate are heated equally, the relative change in the diameters will be the same. Unfortunately, if the end plate heats more than the small end circumference of the frustum, won't the end plate diameter expand then bind rather than move?
I know you're thorough and so must have considered this.
aero
For the diy'sNice info! I have decided to construct a home-built Schlieren Optic system over the next several weeks to analyze the NSF-1701 assembly, under power and not on the balance beam. I will video this.
Found this paper
Please have a look for interest sake, and I would make the same recommendations stated.
the need to place 'a gap at the bottom' of a rack to the first electronic amplifier component for increasing the free air movement and whether we could do the samething could apply to test setups involving magnetrons. There are also some do's and don't do that could be useful as well
I'm of the thought, that targeting "thermal air eddy elimination" will bring everybody a better and more accurate results in that desire to isolating out the direct EM Drive effect by removing or at least minimising and/or linearizing the thermal noise component for easier isolation and removal. I like the quote earlier on a few pages back
"A surrogate to noise is the standard deviation or variance."
so its logical to minimise it.
Schlieren Optics is tell us its there... but that we just cannot see it yet... [thermal air eddies and noise]
much like turbulence you experience in an air plane
One other thermal management reference's pointed to using rectangular slotted holes as being better than round holes for purposes of easy air flow that's why you find slots in more common use on computers.
and yet another promotes what is called 'pin finning' instead of normal finning on Electronic chips
https://en.wikipedia.org/wiki/Thermal_management_of_electronic_devices_and_systems
and how about fin orientation vertical vs horizontal?
another one of those things to ponder about
For the diy'sNice info! I have decided to construct a home-built Schlieren Optic system over the next several weeks to analyze the NSF-1701 assembly, under power and not on the balance beam. I will video this.
Found this paper
Please have a look for interest sake, and I would make the same recommendations stated.
the need to place 'a gap at the bottom' of a rack to the first electronic amplifier component for increasing the free air movement and whether we could do the samething could apply to test setups involving magnetrons. There are also some do's and don't do that could be useful as well
I'm of the thought, that targeting "thermal air eddy elimination" will bring everybody a better and more accurate results in that desire to isolating out the direct EM Drive effect by removing or at least minimising and/or linearizing the thermal noise component for easier isolation and removal. I like the quote earlier on a few pages back
"A surrogate to noise is the standard deviation or variance."
so its logical to minimise it.
Schlieren Optics is tell us its there... but that we just cannot see it yet... [thermal air eddies and noise]
much like turbulence you experience in an air plane
One other thermal management reference's pointed to using rectangular slotted holes as being better than round holes for purposes of easy air flow that's why you find slots in more common use on computers.
and yet another promotes what is called 'pin finning' instead of normal finning on Electronic chips
https://en.wikipedia.org/wiki/Thermal_management_of_electronic_devices_and_systems
and how about fin orientation vertical vs horizontal?
another one of those things to ponder about
For the diy'sNice info! I have decided to construct a home-built Schlieren Optic system over the next several weeks to analyze the NSF-1701 assembly, under power and not on the balance beam. I will video this.
Found this paper
Please have a look for interest sake, and I would make the same recommendations stated.
the need to place 'a gap at the bottom' of a rack to the first electronic amplifier component for increasing the free air movement and whether we could do the samething could apply to test setups involving magnetrons. There are also some do's and don't do that could be useful as well
I'm of the thought, that targeting "thermal air eddy elimination" will bring everybody a better and more accurate results in that desire to isolating out the direct EM Drive effect by removing or at least minimising and/or linearizing the thermal noise component for easier isolation and removal. I like the quote earlier on a few pages back
"A surrogate to noise is the standard deviation or variance."
so its logical to minimise it.
Schlieren Optics is tell us its there... but that we just cannot see it yet... [thermal air eddies and noise]
much like turbulence you experience in an air plane
One other thermal management reference's pointed to using rectangular slotted holes as being better than round holes for purposes of easy air flow that's why you find slots in more common use on computers.
and yet another promotes what is called 'pin finning' instead of normal finning on Electronic chips
https://en.wikipedia.org/wiki/Thermal_management_of_electronic_devices_and_systems
and how about fin orientation vertical vs horizontal?
another one of those things to ponder about
Hook up those dual muffin fans like I suggested, if you wouldn't mind, blowing horizontally off from the top.
Shell
For the diy'sNice info! I have decided to construct a home-built Schlieren Optic system over the next several weeks to analyze the NSF-1701 assembly, under power and not on the balance beam. I will video this.
Found this paper
Please have a look for interest sake, and I would make the same recommendations stated.
the need to place 'a gap at the bottom' of a rack to the first electronic amplifier component for increasing the free air movement and whether we could do the samething could apply to test setups involving magnetrons. There are also some do's and don't do that could be useful as well
I'm of the thought, that targeting "thermal air eddy elimination" will bring everybody a better and more accurate results in that desire to isolating out the direct EM Drive effect by removing or at least minimising and/or linearizing the thermal noise component for easier isolation and removal. I like the quote earlier on a few pages back
"A surrogate to noise is the standard deviation or variance."
so its logical to minimise it.
Schlieren Optics is tell us its there... but that we just cannot see it yet... [thermal air eddies and noise]
much like turbulence you experience in an air plane
One other thermal management reference's pointed to using rectangular slotted holes as being better than round holes for purposes of easy air flow that's why you find slots in more common use on computers.
and yet another promotes what is called 'pin finning' instead of normal finning on Electronic chips
https://en.wikipedia.org/wiki/Thermal_management_of_electronic_devices_and_systems
and how about fin orientation vertical vs horizontal?
another one of those things to ponder about
Hook up those dual muffin fans like I suggested, if you wouldn't mind, blowing horizontally off from the top.
Shell
I'm glad to see its of interest to both seashells and rfmguy
but I can see possible trouble with that arrangement shells...
while I'm enjoying morning coffee, and looking over sketch's it appears there is the makings of an airplane wing here the same effect as blowing over top of a sheet of paper - could be mild lift but I'm sure its there.
So up for some ideas?
1. start by allowing some air space "under" the magnetron so that it disconnects it from the top plate sheet surface perhaps use some adjustable spacer legs
2. consider using he balance beam to find a counter lift angle could be found by adding a few degrees say it works out at 1°-2° of down rake via the adjustable legs to counter balance out any lifting force being generated by the cooling fans. looks like it could be a very much likely to be trial and error approach for a while.
I do give credit though, blowing through sideways seems to be the best mounting direction for fans compared to top and bottom mounting fans.
there is another aspect to think about on this issue: all the heat has go 'somewhere' and that 'somewhere' has to be dissipated heat into air, there is simply no other path.
- its going to mean a lot of hot air going up, and a lot of cold air going down.-
Quote:"The magnetron is rfmwguy's main issue with hot air eddies rising vertically up from the frustum. this creates a low pressure directly above the frustum and the air below the frustum gets pulled along the sidewalls to fill the void. Chaotic actions occur because of the pressure differentials between bottom and top.
By blowing the thermal heated air to the side it can be allowed to rise without adding a chaotic component to the frustum."
Seashells, Agree with comment- and on further thinking about it. Wouldn't it make sense to test with the magnetron Off, and the cooling fans On first in the actual beam configuration as part of a mock up in a calibrating pre-run? and see what the numbers say?
if there was no noticeable movement up or down, or oscillations, with fans On only operation
you would have to say only then that's its onto a "good thing" to do as a standard part off the setup on EMD runs [run cooling air sideways to magnetron with cooling fans], if correct. And if not, well it means looking for other alternatives or ways to mitigate those thermal and air movement effects?
Please don't waste time increasing airflow across the magnetron. Pressure/lift is related to velocity squared, and the fans blowing any air around the magnetron will create chaotic air currents with orders of magnitude more force than relatively slow thermal air currents.Thank you for your post. This is an open discussion and any thoughts on this are very welcome.
Please don't waste time increasing airflow across the magnetron. Pressure/lift is related to velocity squared, and the fans blowing any air around the magnetron will create chaotic air currents with orders of magnitude more force than relatively slow thermal air currents.I would agree the horizontal fans may increase the chimney effect and create unwanted horizontal oscillations. Thermal plumes can only be controlled by ambient air temp equaling device temp...or vacuum testing.
In reply to shell: Assymetric horizontal airflow creates lift. Since the magnetron is not a symmetric airfoil, it will have chaotic, turbulent airflow around it at best. Characterizing the resulting forces accurately enough to discern an underlying mN signal under it would be difficult.
Considering that, work to streamline the magnetron may help regulate the lift and drag from the convection currents.
Please don't waste time increasing airflow across the magnetron. Pressure/lift is related to velocity squared, and the fans blowing any air around the magnetron will create chaotic air currents with orders of magnitude more force than relatively slow thermal air currents.I would agree the horizontal fans may increase the chimney effect and create unwanted horizontal oscillations. Thermal plumes can only be controlled by ambient air temp equaling device temp...or vacuum testing.
This thought experiment has kept me up at nights...finally thought it best to not add anything and characterize lift, using dsoftware to "extract" displacement changes during mag ON state. Following an ON state, the lift rises a a fairly predictanbe rate with some minor variations as the heat plumes exit the frustum somewhat uniformly.
However, am curious enough to use Schleiren photography to see this for myself. Though my test stand is temporarily disassembled, can do a static power test and shoot some video later this year...if I get some donation help. The proper mirrors and light sources are not cheap.
Disappointed to notice wallofwolfstreet has left the building here and on reddit apparently. Anyone have the details on this? I enjoyed his posts, even tho he was not a firm believer...
Please don't waste time increasing airflow across the magnetron. Pressure/lift is related to velocity squared, and the fans blowing any air around the magnetron will create chaotic air currents with orders of magnitude more force than relatively slow thermal air currents.I would agree the horizontal fans may increase the chimney effect and create unwanted horizontal oscillations. Thermal plumes can only be controlled by ambient air temp equaling device temp...or vacuum testing.
This thought experiment has kept me up at nights...finally thought it best to not add anything and characterize lift, using dsoftware to "extract" displacement changes during mag ON state. Following an ON state, the lift rises a a fairly predictanbe rate with some minor variations as the heat plumes exit the frustum somewhat uniformly.
However, am curious enough to use Schleiren photography to see this for myself. Though my test stand is temporarily disassembled, can do a static power test and shoot some video later this year...if I get some donation help. The proper mirrors and light sources are not cheap.
I've been thinking about this quite a bit as well. I agree that the use of active (fan) cooling is likely to introduce very chaotic flow and -at the level of signal we are looking for here - more noise than they eliminate.
Vacuum is one way of course - likely the best and as is typically for the best - the most expensive route. One of the reasons I am strongly considering a rotary stage setup for my DIY configuration is that then the force vector being measured will be perpendicular to thermal effects (if designed carefully).
Another approach which we touched on a few pages back was the second cavity arranged in such a way as to cancel (or nearly so ) thermal effects while adding "emdrive" effects. While I was advocating the need for making the cavities as near identical as possible - in reality I was wrong and as was pointed out that really isn't necessary - just getting "close" will improve the S/N.
Just random thoughts on a Sunday afternoon.
NSF-1701 Paper Update. With thanks to many, I am releasing my paper a day early. I look forward to your commentary.
All the best,
Dave
NSF-1701 Paper Update. With thanks to many, I am releasing my paper a day early. I look forward to your commentary.Can't agree (or at least I am not sure about) your Q definition is really helpful, I think it leads to some confusion about it, S11 and S12 measurements are well defined IMHO.
All the best,
Dave
Disappointed to notice wallofwolfstreet has left the building here and on reddit apparently. Anyone have the details on this? I enjoyed his posts, even tho he was not a firm believer...
I have also been noticing a drop in post count here and reddit too - particularly from some of the more prolific contributors. If I were a conspiracy oriented person - which I am not - I would wonder if it has anything to do with the recent reports with more and better quality data saying SOMETHING is happening that needs looked at.
Surely if the data were unequivocally indicating "nothing to see here, move along, we've all been wasting our time" some previous purveyors of preserving the status quo would be shouting that from the rooftops but instead I find myself hearing crickets from them.
But likewise some of those who were either supportive of the concept or at least supportive of impartially investigation and welcoming of data of all sorts seemed to have dropped of in volume and scope of their posts, not everyone by any means - but some real luminaries none the less.
If it were August I would suspect that lots of folks were just taking a late summer vacation or if September I would suspect many are just getting down to the new semester at their institutions.
If this was a Hollywood conspiracy theory movie I would be suspecting the hero was going to find these missing voices were part of a vast group of commercial/government/academic investigators who had found something really significant and had been told to be quiet. And of course he/she would have to expose them and the secret and get the girl/boy and live happy ever after (perhaps on Pluto heh heh).
But of course that's just crazy talk - so I suspect they have all been off waiting in line to see "The Martian" in 3D. (planning to myself RSN).
Just some weirder thoughts on a Sunday afternoon - after an adult beverage or two.
Herman
Disappointed to notice wallofwolfstreet has left the building here and on reddit apparently. Anyone have the details on this? I enjoyed his posts, even tho he was not a firm believer...