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#1960 by WarpTech on 23 Oct, 2016 19:29
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What is this particular 'statistical analysis' trying to achieve? It certainly isn't useful in predicting thrust/power, because the explanatory variable itself includes thrust/power. However, for a casual observer who doesn't know what R2/R1 means the plots definitely give that impression.
I first made that very same point, and I made it explicitly, rather than using words.
Todd chose those variables. For me, formulas, plots and analysis speak for themselves more clearly than using words.
You are welcome to use words, or nothing (no discussion of the variables and the formula, no plots and no statistical analysis), if you prefer.
I already pointed out a useful thing that came from the analysis (Yang 3).
Here is another one: obviously the EM Drive data is not random or faked data, because it plots the way it is supposed to behave, when regressed. The different L, Cos[theta] and omega for Cannae fall on their own line, and as an outlier form the truncated cone geometry. That does not mean that the EM Drive can necessarily be used for Space Propulsion, it just shows that the data is not random.
How could Yang 3 not be on the same line? It's the same geometry and frequency as the other two Yang's tests. And I don't get your point about not faked/random data: it shows that device dimensions and frequency used are not random, but nothing at all about thrust/power.
My original objective was to see how much asymmetry is required to get this Thrust to Power ratio, since perfect symmetry would be Log(1) = 0, and there would be no thrust. So what it was supposed to represent is how much asymmetry is required to get this thrust to power ratio. However, plotting it as a Log vs Log is just revealing the similar geometrical factors.
There are too many unknowns to say any of this is good data. Thrust to Power ratio is based on raw input power, not the amount of power actually coupled into the cavity. So that number in itself is not to be trusted.
The Thrust to Power ratio calculated is the inverse of the Thrust velocity. In my model, the inverse of the Thrust velocity is -dtau/dr, where r is the distance from the apex of the cone and tau is the decay time of the EM wave as a function of r. -
#1961 by demofsky on 23 Oct, 2016 23:32
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It seems that what people criticizing the plotting may be missing is that this relationship of Thrust/Power vs Ln[R2/R1] implies, besides geometry, the quality of resonance factor Q, which varies by several orders of magnitude between Tajmar's EM Drive and Shawyer's and Yang's, and does not appear as an explicit variable in the regression plot.
A couple of other interesting correlations seem to be happening with this chart. All the vacuum experiments are at the bottom. Also the TMxxx experiments (especially TM212) are at the bottom. The TE012 and TE013 experiments are at the top.
So is this simply about geometry controlling modes or is there something else? -
#1962 by rfmwguy on 24 Oct, 2016 13:47
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I guess I will post this here, as I did on Reddit where I asked people's opinion of divulging EmDrive information.
Based on my own concerns, the number of new people asking for help building plus the feedback I received on reddit, I've decided not to help others design, build or test an EmDrive. The exception to this is the very small group of individuals I currently work with, know and trust to have the credentials to work with this dangerous piece of gear.
As I see this project move from conjecture to reality, safety concerns have to be the #1 priority. It bears repeating, as I've done so during every guest interview I've done on science podcasts.
Do not consider live testing of an EmDrive unless you have experience in High Voltage, High Power RF and general RFI/EMI experience. Yes, the device is fascinating and has a great potential...it also has a danger associated with it. Leave it to the experts. - Dave
/soapbox
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#1963 by Monomorphic on 24 Oct, 2016 15:10
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I guess I will post this here, as I did on Reddit where I asked people's opinion of divulging EmDrive information.
Based on my own concerns, the number of new people asking for help building plus the feedback I received on reddit, I've decided not to help others design, build or test an EmDrive. The exception to this is the very small group of individuals I currently work with, know and trust to have the credentials to work with this dangerous piece of gear.
As I see this project move from conjecture to reality, safety concerns have to be the #1 priority. It bears repeating, as I've done so during every guest interview I've done on science podcasts.
Do not consider live testing of an EmDrive unless you have experience in High Voltage, High Power RF and general RFI/EMI experience. Yes, the device is fascinating and has a great potential...it also has a danger associated with it. Leave it to the experts. - Dave
/soapbox
I would definitely not recommend that they go the direction of using a microwave magnetron for their RF source. The high RF output and high voltage power supply is where the danger is. But if they want to pick up a 50-100W amp, I say go for it. Just be weary of regulations on broadcasting RF. Resonant cavity experiments are exempt since they do not intend to radiate, but there can be leaks!
Speaking from personal experience, the magnetron is a terrible choice for many other reasons besides the danger: frequency drift, runaway thermal heating, difficult to make battery powered, vortex shedding from the heatsink, thermal heating/expansion of the leads, difficulty in modeling the antenna cap, it's heavy... the list goes on and every single problem has to be accounted for. -
#1964 by SeeShells on 24 Oct, 2016 15:11
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I did something similar last year using the data that was available on wiki. It showed that even for the couple watts that was input for the EagleWorks test the thrust ration was higher for the TE012. I built taking these facts into account a TE012 frustum and then modified it.It seems that what people criticizing the plotting may be missing is that this relationship of Thrust/Power vs Ln[R2/R1] implies, besides geometry, the quality of resonance factor Q, which varies by several orders of magnitude between Tajmar's EM Drive and Shawyer's and Yang's, and does not appear as an explicit variable in the regression plot.
A couple of other interesting correlations seem to be happening with this chart. All the vacuum experiments are at the bottom. Also the TMxxx experiments (especially TM212) are at the bottom. The TE012 and TE013 experiments are at the top.
So is this simply about geometry controlling modes or is there something else?
http://emdrive.wiki/Experimental_Results
Shell
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#1965 by Rodal on 24 Oct, 2016 15:17
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I guess I will post this here, as I did on Reddit where I asked people's opinion of divulging EmDrive information.
Based on my own concerns, the number of new people asking for help building plus the feedback I received on reddit, I've decided not to help others design, build or test an EmDrive. The exception to this is the very small group of individuals I currently work with, know and trust to have the credentials to work with this dangerous piece of gear.
As I see this project move from conjecture to reality, safety concerns have to be the #1 priority. It bears repeating, as I've done so during every guest interview I've done on science podcasts.
Do not consider live testing of an EmDrive unless you have experience in High Voltage, High Power RF and general RFI/EMI experience. Yes, the device is fascinating and has a great potential...it also has a danger associated with it. Leave it to the experts. - Dave
/soapbox
I would definitely not recommend that they go the direction of using a microwave magnetron for their RF source. The high RF output and high voltage power supply is where the danger is. But if they want to pick up a 50-100W amp, I say go for it. Just be weary of regulations on broadcasting RF. Resonant cavity experiments are exempt since they do not intend to radiate, but there can be leaks!
Speaking from personal experience, the magnetron is a terrible choice for many other reasons besides the danger: frequency drift, runaway thermal heating, difficult to make battery powered, vortex shedding from the heatsink, thermal heating/expansion of the leads, difficulty in modeling the antenna cap, it's heavy... the list goes on and every single problem has to be accounted for.
It is great to see a consensus being formed advising people not to use << the magnetron is a terrible choice>>.
Eugene Samsonov (NSF user "RFPlumber") was the first "citizen scientist" to conduct EM Drive experiments without a magnetron and using a battery in a self-integrated test, using no power cables whatsoever.
The only researcher (aside from Prof. Juan Yang) to report EM Drive experiments without power cables, to this date.
http://vixra.org/abs/1603.0153
Samsonov deserves great credit for this accomplishment. Samsonov concluded from his experiment that there was no thrust, within the relative error of his experiments.
We look forward to others following the trailblazing of Samsonov by conducting further tests without the awful magnetron, which you are right << the magnetron is a terrible choice>>,and instead using a battery operated test without power cables. -
#1966 by SeeShells on 24 Oct, 2016 15:39
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You're correct it's easier to just slap a solid state driver.I guess I will post this here, as I did on Reddit where I asked people's opinion of divulging EmDrive information.
Based on my own concerns, the number of new people asking for help building plus the feedback I received on reddit, I've decided not to help others design, build or test an EmDrive. The exception to this is the very small group of individuals I currently work with, know and trust to have the credentials to work with this dangerous piece of gear.
As I see this project move from conjecture to reality, safety concerns have to be the #1 priority. It bears repeating, as I've done so during every guest interview I've done on science podcasts.
Do not consider live testing of an EmDrive unless you have experience in High Voltage, High Power RF and general RFI/EMI experience. Yes, the device is fascinating and has a great potential...it also has a danger associated with it. Leave it to the experts. - Dave
/soapbox
I would definitely not recommend that they go the direction of using a microwave magnetron for their RF source. The high RF output and high voltage power supply is where the danger is. But if they want to pick up a 50-100W amp, I say go for it. And speaking from personal experience, the magnetron is a terrible choice for many other reasons besides the danger: frequency drift, runaway thermal heating, difficult to make battery powered, vortex shedding from the heatsink, thermal heating/expansion of the leads, difficulty in modeling the antenna cap, it's heavy... the list goes on and every single problem has to be accounted for.
The list of things you must do to make the magnetron tube behave in a safe and well determined envelope is not easy. Although I'm old enough that I teethed on vacuum tubes and the magnetron is just a high power vacuum tube. I designed for that. I ended up with a highly stable, frequency locked, narrow band magnetron, locking is done in a resonate waveguide in the electronics box and taking that output to the coax. That has a 100% duty cycle.
Isolating the entire 5Kv variable power supply, magnetron, thermal cooling it all is not an easy task and then providing the RF to the frustum is another issue. Although it provides a great testing bed that's virtually bullet proof.
So saying a magnetron can't be done is not quite true and saying the output can't be tamed and thermals controlled is not correct. It's just a lot of work to be able to use the >1Kw output. Plus, if you don't know what your doing, even a solid state, 50 watts of microwave can damage and hurt you.
I've been building electronics for 50 years and knowing what I was dealing with and what it could do to made me extremely cautious.
Playing it safe in the Rockies,
Shell
Added: Verbage garbage correction -
#1967 by Monomorphic on 24 Oct, 2016 15:45
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Samsonov deserves great credit for this accomplishment. Samsonov concluded from his experiment that there was no thrust, within the relative error of his experiments.
I agree that Samsonov's experiment is the gold standard - solid state and battery powered - which is the direction most of us are going now. I would also add to that list a frustum machined from solid copper and not thin wall copper.
I've looked closely at Samsonov's frustum and can say with confidence he probably never achieved resonance. Since he did not confirm resonance with an IR camera, his null result should really be labeled inconclusive. And with the end-plates attached in only four places each, basically he created a frustum shaped antenna, not a true cavity. An IR video would likely have shown the RF escaping through the slits and no resonance pattern.
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#1968 by Rodal on 24 Oct, 2016 15:58
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...I've looked closely at Samsonov's frustum and can say with confidence he probably never achieved resonance. Since he did not confirm resonance with an IR camera, his null result should really be labeled inconclusive....
Let's also consider:
1) Samsonov had significant previous professional expertise in electromagnetically resonant Radio Frequency Cavities and waveguides. He wrote that he assessed resonance based on his scalar network analyzer:
Samsonov wrote:Quote from: SamsonovThe author then built the actual cavity from a sheet of 0.5 mm copper using a pair of FR4 plates for side walls and verified its resonance modes with a scalar network analyzer (Figure 4(c)).
(Figure 4c from Samsonov, showing resonance, with S11 plot, shown below in attachment)
2) Samsonov modeled his experiments, ahead of time, using COMSOL Finite Element Analysis
3) Samsonov determined that his experiment was going to resonate in TE012 mode shape. All TE0np mode shapes are notorious for:
a) resulting in higher Q than TM mode shapes, hence the bandwidth of resonance is narrower than for TM mode shapes. To be at resonance and stay at resonance is more difficult for TE0np modes, as also experienced by NASA for TE012, which decided to continue with TM212 because it was too difficult to excite TE012.
b) as documented in several textbooks (i.e. Collin) it is more difficult to excite a TE mode shape than to excite a TM mode shape
4) It is much more difficult to verify a TE mode shape than a TM mode shape using an infrared thermal camera because the TM mode shapes have associated currents due to the parallel transverse magnetic field in the azimuthal direction and due to the normal electric field in the axial direction, while the TE modes do not produce significant electric fields on the metal, because TE modes do not have an electric field component normal to the metal. There is only the magnetic field perpendicular to the azimuthal and longitudinal directions that is parallel to the (big and small) ends that can produce a current on the wall. Since the TE mode shapes result in higher Q, there is less dissipation at the walls and hence the TE0np mode shapes are more difficult to assess with an infrared thermal camera.
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#1969 by SeeShells on 24 Oct, 2016 16:25
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I saw the gaps between the FR4 and cone as well and thought the same as you that this would lead to killing the Q and any hope of measured thrust.Samsonov deserves great credit for this accomplishment. Samsonov concluded from his experiment that there was no thrust, within the relative error of his experiments.
I agree that Samsonov's experiment is the gold standard - solid state and battery powered - which is the direction most of us are going now. I would also add to that list a frustum machined from solid copper and not thin wall copper.
I've looked closely at Samsonov's frustum and can say with confidence he probably never achieved resonance. Since he did not confirm resonance with an IR camera, his null result should really be labeled inconclusive. And with the end-plates attached in only four places each, basically he created a frustum shaped antenna, not a true cavity. An IR video would likely have shown the RF escaping through the slits and no resonance pattern.
This drive is easy to make not work, but incredibly tough to make work. So many details have to be exactly right.
Shell
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#1970 by Bob012345 on 24 Oct, 2016 16:37
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I guess I will post this here, as I did on Reddit where I asked people's opinion of divulging EmDrive information.
Based on my own concerns, the number of new people asking for help building plus the feedback I received on reddit, I've decided not to help others design, build or test an EmDrive. The exception to this is the very small group of individuals I currently work with, know and trust to have the credentials to work with this dangerous piece of gear.
As I see this project move from conjecture to reality, safety concerns have to be the #1 priority. It bears repeating, as I've done so during every guest interview I've done on science podcasts.
Do not consider live testing of an EmDrive unless you have experience in High Voltage, High Power RF and general RFI/EMI experience. Yes, the device is fascinating and has a great potential...it also has a danger associated with it. Leave it to the experts. - Dave
/soapbox
Thanks, I'll take your advice. I would like to play around with magnetic fields and forces on wires though involving ~1-3 Amps DC and maybe around 1000 turn coils. Is there a way I could accidentally harm myself? -
#1971 by Bob012345 on 24 Oct, 2016 16:47
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Interesting rumour just arrived.
Seems the Chinese have tested a EmDrive on station but have no idea why it works. Maybe they should talk to Roger or Gilo Industries?
Sure hope the X-37B is testing a better EmDrive on station.
So you're saying it worked in space? Any numbers? -
#1972 by SeeShells on 24 Oct, 2016 16:57
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Regarding the network analyzer. They normally output a increasing sweep frequency to measure feedback at a set sample rate time. The sweeping output doesn't create a stable standing wave mode as it sweeps frequency in the frustum, especially when dealing with a picky narrow BW mode TE012. http://tinyurl.com/jjo7pja...I've looked closely at Samsonov's frustum and can say with confidence he probably never achieved resonance. Since he did not confirm resonance with an IR camera, his null result should really be labeled inconclusive....
Let's also consider:
1) Samsonov had significant previous professional expertise in electromagnetically resonant Radio Frequency Cavities and waveguides. He wrote that he assessed resonance based on his scalar network analyzer:
Samsonov wrote:Quote from: SamsonovThe author then built the actual cavity from a sheet of 0.5 mm copper using a pair of FR4 plates for side walls and verified its resonance modes with a scalar network analyzer (Figure 4(c)).
(Figure 4c from Samsonov, showing resonance, with S11 plot, shown below in attachment)
2) Samsonov modeled his experiments, ahead of time, using COMSOL Finite Element Analysis
3) Samsonov determined that his experiment was going to resonate in TE012 mode shape. All TE0np mode shapes are notorious for:
a) resulting in higher Q than TM mode shapes, hence the bandwidth of resonance is narrower than for TM mode shapes. To be at resonance and stay at resonance is more difficult for TE0np modes, as also experienced by NASA for TE012, which decided to continue with TM212 because it was too difficult to excite TE012.
b) as documented in several textbooks (i.e. Collin) it is more difficult to excite a TE mode shape than to excite a TM mode shape
4) It is much more difficult to verify a TE mode shape than a TM mode shape using an infrared thermal camera because the TM mode shapes have associated currents due to the parallel transverse magnetic field in the azimuthal direction and due to the normal electric field in the axial direction, while the TE modes do not produce significant electric fields on the metal, because TE modes do not have an electric field component normal to the metal. There is only the magnetic field perpendicular to the azimuthal and longitudinal directions that is parallel to the (big and small) ends that can produce a current on the wall. Since the TE mode shapes result in higher Q, there is less dissipation at the walls and hence the TE0np mode shapes are more difficult to assess with an infrared thermal camera.
He was down around 20db. rfmwguy or monomorphic what was your VNA showing?
Shell -
#1973 by rfmwguy on 24 Oct, 2016 16:59
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You beat me to it Jamie. There was no way resonance was going to be attained with the mechanical design Samsonov had. His very low power combined with his inexperience with mechanical cavity design was never going to produce a force above error IMO. Its disappointing he wrote a paper about it after only one quick attempt to try it out.Samsonov deserves great credit for this accomplishment. Samsonov concluded from his experiment that there was no thrust, within the relative error of his experiments.
I agree that Samsonov's experiment is the gold standard - solid state and battery powered - which is the direction most of us are going now. I would also add to that list a frustum machined from solid copper and not thin wall copper.
I've looked closely at Samsonov's frustum and can say with confidence he probably never achieved resonance. Since he did not confirm resonance with an IR camera, his null result should really be labeled inconclusive. And with the end-plates attached in only four places each, basically he created a frustum shaped antenna, not a true cavity. An IR video would likely have shown the RF escaping through the slits and no resonance pattern.
While his basic idea was on the right track, his execution was not. Unfortunately, many keep referring to his effort as proof there is no thrust. Thanks for the keen observation. -
#1974 by SeeShells on 24 Oct, 2016 17:04
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Yes, very defiantly. That's a great flyback transformer, a real heart stopper if you're shocked.I guess I will post this here, as I did on Reddit where I asked people's opinion of divulging EmDrive information.
Based on my own concerns, the number of new people asking for help building plus the feedback I received on reddit, I've decided not to help others design, build or test an EmDrive. The exception to this is the very small group of individuals I currently work with, know and trust to have the credentials to work with this dangerous piece of gear.
As I see this project move from conjecture to reality, safety concerns have to be the #1 priority. It bears repeating, as I've done so during every guest interview I've done on science podcasts.
Do not consider live testing of an EmDrive unless you have experience in High Voltage, High Power RF and general RFI/EMI experience. Yes, the device is fascinating and has a great potential...it also has a danger associated with it. Leave it to the experts. - Dave
/soapbox
Thanks, I'll take your advice. I would like to play around with magnetic fields and forces on wires though involving ~1-3 Amps DC and maybe around 1000 turn coils. Is there a way I could accidentally harm myself?
Shell -
#1975 by rfmwguy on 24 Oct, 2016 17:06
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20dB indicates poor Q. It is what I was seeing on 1701. !701A was around double that with polishing, soldering and sealed seams. One of the sweeps I did is below. I saw as high as 60dB RL, but could not reproduce it. Most sweeps were a minimum 40dB.
Regarding the network analyzer. They normally output a increasing sweep frequency to measure feedback at a set sample rate time. The sweeping output doesn't create a stable standing wave mode as it sweeps frequency in the frustum, especially when dealing with a picky narrow BW mode TE012. http://tinyurl.com/jjo7pja...I've looked closely at Samsonov's frustum and can say with confidence he probably never achieved resonance. Since he did not confirm resonance with an IR camera, his null result should really be labeled inconclusive....
Let's also consider:
1) Samsonov had significant previous professional expertise in electromagnetically resonant Radio Frequency Cavities and waveguides. He wrote that he assessed resonance based on his scalar network analyzer:
Samsonov wrote:Quote from: SamsonovThe author then built the actual cavity from a sheet of 0.5 mm copper using a pair of FR4 plates for side walls and verified its resonance modes with a scalar network analyzer (Figure 4(c)).
(Figure 4c from Samsonov, showing resonance, with S11 plot, shown below in attachment)
2) Samsonov modeled his experiments, ahead of time, using COMSOL Finite Element Analysis
3) Samsonov determined that his experiment was going to resonate in TE012 mode shape. All TE0np mode shapes are notorious for:
a) resulting in higher Q than TM mode shapes, hence the bandwidth of resonance is narrower than for TM mode shapes. To be at resonance and stay at resonance is more difficult for TE0np modes, as also experienced by NASA for TE012, which decided to continue with TM212 because it was too difficult to excite TE012.
b) as documented in several textbooks (i.e. Collin) it is more difficult to excite a TE mode shape than to excite a TM mode shape
4) It is much more difficult to verify a TE mode shape than a TM mode shape using an infrared thermal camera because the TM mode shapes have associated currents due to the parallel transverse magnetic field in the azimuthal direction and due to the normal electric field in the axial direction, while the TE modes do not produce significant electric fields on the metal, because TE modes do not have an electric field component normal to the metal. There is only the magnetic field perpendicular to the azimuthal and longitudinal directions that is parallel to the (big and small) ends that can produce a current on the wall. Since the TE mode shapes result in higher Q, there is less dissipation at the walls and hence the TE0np mode shapes are more difficult to assess with an infrared thermal camera.
He was down around 20db. rfmwguy or monomorphic what was your VNA showing?
Shell
p.s. WarpTech, if you want to update my center freq using this chart, feel free. The experimental antenna did change the ctr from ~2441, but the general RL shape was not impacted.
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#1976 by rfmwguy on 24 Oct, 2016 17:24
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Its worse than that I'm afraid...this is copper tape folded and partially soldered. Adhesives, even "conductive" adhesives are not friendly with MW. I didn't feel like criticizing his efforts...that is until his paper was put out claiming no thrust. Fair game now.
I saw the gaps between the FR4 and cone as well and thought the same as you that this would lead to killing the Q and any hope of measured thrust.Samsonov deserves great credit for this accomplishment. Samsonov concluded from his experiment that there was no thrust, within the relative error of his experiments.
I agree that Samsonov's experiment is the gold standard - solid state and battery powered - which is the direction most of us are going now. I would also add to that list a frustum machined from solid copper and not thin wall copper.
I've looked closely at Samsonov's frustum and can say with confidence he probably never achieved resonance. Since he did not confirm resonance with an IR camera, his null result should really be labeled inconclusive. And with the end-plates attached in only four places each, basically he created a frustum shaped antenna, not a true cavity. An IR video would likely have shown the RF escaping through the slits and no resonance pattern.
This drive is easy to make not work, but incredibly tough to make work. So many details have to be exactly right.
Shell
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#1977 by Bob012345 on 24 Oct, 2016 17:33
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Yes, very defiantly. That's a great flyback transformer, a real heart stopper if you're shocked.I guess I will post this here, as I did on Reddit where I asked people's opinion of divulging EmDrive information.
Based on my own concerns, the number of new people asking for help building plus the feedback I received on reddit, I've decided not to help others design, build or test an EmDrive. The exception to this is the very small group of individuals I currently work with, know and trust to have the credentials to work with this dangerous piece of gear.
As I see this project move from conjecture to reality, safety concerns have to be the #1 priority. It bears repeating, as I've done so during every guest interview I've done on science podcasts.
Do not consider live testing of an EmDrive unless you have experience in High Voltage, High Power RF and general RFI/EMI experience. Yes, the device is fascinating and has a great potential...it also has a danger associated with it. Leave it to the experts. - Dave
/soapbox
Thanks, I'll take your advice. I would like to play around with magnetic fields and forces on wires though involving ~1-3 Amps DC and maybe around 1000 turn coils. Is there a way I could accidentally harm myself?
Shell
Thanks. My concept amounted to a single wire wound in a toroidal coil where ever few turns the wire passes through the middle of the coil so as to be inside the magnetic field. The same current creates the field and also passes through the field so has a force on it (of course, unfortunately, not a net force). It ends up being just a DC variant of a Slepian 'drive'. I was thinking since it's only a few Volts DC it would just take a few seconds to ramp up or down due to inductance but I can see now there could be a huge back emf if shorted. Thanks again. -
#1978 by X_RaY on 24 Oct, 2016 18:22
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VNA's work in FSCW mode (frequency stepped, continuous wave). The VCO(voltage controlled oscillator) will be adjusted to a defined tuning voltage* which may an integer of a PLL(phase locked loop) based frequency.
Regarding the network analyzer. They normally output a increasing sweep frequency to measure feedback at a set sample rate time. The sweeping output doesn't create a stable standing wave mode as it sweeps frequency in the frustum, especially when dealing with a picky narrow BW mode TE012. http://tinyurl.com/jjo7pja...I've looked closely at Samsonov's frustum and can say with confidence he probably never achieved resonance. Since he did not confirm resonance with an IR camera, his null result should really be labeled inconclusive....
Let's also consider:
1) Samsonov had significant previous professional expertise in electromagnetically resonant Radio Frequency Cavities and waveguides. He wrote that he assessed resonance based on his scalar network analyzer:
Samsonov wrote:Quote from: SamsonovThe author then built the actual cavity from a sheet of 0.5 mm copper using a pair of FR4 plates for side walls and verified its resonance modes with a scalar network analyzer (Figure 4(c)).
(Figure 4c from Samsonov, showing resonance, with S11 plot, shown below in attachment)
2) Samsonov modeled his experiments, ahead of time, using COMSOL Finite Element Analysis
3) Samsonov determined that his experiment was going to resonate in TE012 mode shape. All TE0np mode shapes are notorious for:
a) resulting in higher Q than TM mode shapes, hence the bandwidth of resonance is narrower than for TM mode shapes. To be at resonance and stay at resonance is more difficult for TE0np modes, as also experienced by NASA for TE012, which decided to continue with TM212 because it was too difficult to excite TE012.
b) as documented in several textbooks (i.e. Collin) it is more difficult to excite a TE mode shape than to excite a TM mode shape
4) It is much more difficult to verify a TE mode shape than a TM mode shape using an infrared thermal camera because the TM mode shapes have associated currents due to the parallel transverse magnetic field in the azimuthal direction and due to the normal electric field in the axial direction, while the TE modes do not produce significant electric fields on the metal, because TE modes do not have an electric field component normal to the metal. There is only the magnetic field perpendicular to the azimuthal and longitudinal directions that is parallel to the (big and small) ends that can produce a current on the wall. Since the TE mode shapes result in higher Q, there is less dissipation at the walls and hence the TE0np mode shapes are more difficult to assess with an infrared thermal camera.
He was down around 20db. rfmwguy or monomorphic what was your VNA showing?
Shell
After a settling time the system is in a steady state mode, than the measurement of the voltage of the outputmixers is performed and digitalizized with an analog/digital converter** to derive the scattering matrix.
After this the next frequency step will be adjusted, and so on.
The whole process to scan a frequency band this way takes only a few seconds (depending on the total number of samples/frequency).
There is no continuous chirp signal at that measurement
* In fact the exact voltage will be regulated with the PLL to hold the frequency stable.
** There is always an oversampling/integration time, which means not only one voltage sample is taken at each frequency, because of the thermal noise at the detector. -
#1979 by Rodal on 24 Oct, 2016 18:27
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Samsonov (RFPlumber) is the only citizen scientist to this date that has performed experiments without power cables (shown by Prof. Yang to be the source of experimental artifacts in her prior experiments), and using a battery in a self-integrated package not using the awful magnetron (responsible for lots of experimental artifacts).
Samsonov concluded that there was no thrust in the EM Drive within the relative error of his experiments. Naturally, Samsonov's finding of no thrust is not pleasing to those that would like to see a revolutionary breaktrhough in Space Propulsion. Naturally we all like to hear positive news rather than negative news.
Samsonov (RFPlumber) stopped posting at NSF, more than 7 months ago.
It would have been better to address criticism of his experimental technique while he could answer critics at NSF, rather than now, since he may (or may not) have good answers to address such criticism. But hindsight is 20/20
Hopefully in the future we can address such criticism of experiments in a timely manner while experiments are being reported at NSF rather than months afterwards, when the researcher is no longer active at NSF.
