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#1980 by rfmwguy on 24 Oct, 2016 19:40
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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).
I assume you are addressing me? If this is the case, like you, there were times I did not post actively on NSF like back then. His departure and my inactive status should not preclude very valid points by several actual builders, especially considering you made mention of his expertise without apparent evidence. This was a poorly constructed cavity that any engineer with RF experience would recognize as poor. With that, I would characterize this as lack of expertise with evidence posted by monomorphic and shell.
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 with 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in a timely manner while experiments are being reported at NSF rather than months afterwards, when the researcher is no longer active at NSF.
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#1981 by chongma on 24 Oct, 2016 21:10
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Are there specialist companies that can build and test a cavity to resonance? Or is it so state of the art that builders have to figure out the method themselves?
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#1982 by rfmwguy on 24 Oct, 2016 21:26
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Are there specialist companies that can build and test a cavity to resonance? Or is it so state of the art that builders have to figure out the method themselves?
Testing is by anyone with an RF lab is available. Building one is a different deal altogether. I would say no. -
#1983 by WarpTech on 24 Oct, 2016 21:54
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Are there specialist companies that can build and test a cavity to resonance? Or is it so state of the art that builders have to figure out the method themselves?
The lowest cost way to make a solid cavity would be to create a 3D printed part and then have it sand casted in Aluminum. I believe this is how Shawyer is doing it. It's much cheaper than hogging it out of a solid block. -
#1984 by SeeShells on 24 Oct, 2016 23:11
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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).
Dr. Rodal,
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.
I politely voiced my criticisms on his build and testing, even offered advise to correct what I saw was quite obvious, but he refused to answer me. So be it was my thought, it will be a failed test. It was. Even though he got some things right, when you're running low power as he was your build should be airtight.
Considering these issues of gaps in construction, untested antenna design, coax cable length for the antenna, just covering a few it would mean to me those issues negate calling it a null test. Inclusive would be a better term.
Shell -
#1985 by WarpTech on 25 Oct, 2016 03:22
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Modes of a parabolic microcavity. It's not a frustum, but it's interestingly close.
http://pages.uoregon.edu/noeckel/publications/dome.pdf
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#1986 by SeeShells on 25 Oct, 2016 03:35
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Modes of a parabolic microcavity. It's not a frustum, but it's interestingly close.
Nice, a bit of gold you found WarpTech.
http://pages.uoregon.edu/noeckel/publications/dome.pdf
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#1987 by WarpTech on 25 Oct, 2016 03:55
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Modes of a parabolic microcavity. It's not a frustum, but it's interestingly close.
Nice, a bit of gold you found WarpTech.
http://pages.uoregon.edu/noeckel/publications/dome.pdf
Shell
The reflection of the "other end" in the flat end plates of the frustum make it not so asymmetrical after all. There is always a reflected symmetry on the flat end plates. -
#1988 by SeeShells on 25 Oct, 2016 04:42
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Yep. Although the conical walls and the large spherical endplate are critical to the mode shapes and energy concentrations in the small endplate area.Modes of a parabolic microcavity. It's not a frustum, but it's interestingly close.
Nice, a bit of gold you found WarpTech.
http://pages.uoregon.edu/noeckel/publications/dome.pdf
Shell
The reflection of the "other end" in the flat end plates of the frustum make it not so asymmetrical after all. There is always a reflected symmetry on the flat end plates.
Shell
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#1989 by zen-in on 25 Oct, 2016 05:12
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There have been other experimenters from whom we have not heard in some time. Solid state 50 - 100 Watt 2.5 GHz RF amp are not cheap and they don't seem to last very long when used to drive cone shaped cavities; even by the more experienced experimenters on this forum. The high failure rate of solid state amps would suggest that resonance is not being achieved for very long. So any criticism of Samsonov's cavity could apply to anyone else's. Everyone agrees a torque pendulum experiment that is battery powered and has no cables would eliminate several error sources. However that appears to be almost impossible because of the failure rate of higher power solid state RF amps. We do have Yang's second series of experiments that used a magnetron to fill in that one kind of experiment. Maybe there are other experiments that can be done to eliminate the possibility of error forces and reinforce the EM-Drive theory.
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. -
#1990 by chongma on 25 Oct, 2016 11:01
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There have been other experimenters from whom we have not heard in some time. Solid state 50 - 100 Watt 2.5 GHz RF amp are not cheap and they don't seem to last very long when used to drive cone shaped cavities; even by the more experienced experimenters on this forum. The high failure rate of solid state amps would suggest that resonance is not being achieved for very long. So any criticism of Samsonov's cavity could apply to anyone else's. Everyone agrees a torque pendulum experiment that is battery powered and has no cables would eliminate several error sources. However that appears to be almost impossible because of the failure rate of higher power solid state RF amps. We do have Yang's second series of experiments that used a magnetron to fill in that one kind of experiment. Maybe there are other experiments that can be done to eliminate the possibility of error forces and reinforce the EM-Drive theory.
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.
any design needs to include some way of stopping the energy feeding back into the rf source. to allow the rf source to be destroyed after a few experiments is wasteful and expensive. not to mention any results obtained would be dubious if the rf source was feeding back on itself -
#1991 by Peter Lauwer on 25 Oct, 2016 12:45
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any design needs to include some way of stopping the energy feeding back into the rf source. to allow the rf source to be destroyed after a few experiments is wasteful and expensive. not to mention any results obtained would be dubious if the rf source was feeding back on itself
I plan to use an isolator or circulator (and monitor the reflected signal). You agree?
Peter -
#1992 by chongma on 25 Oct, 2016 14:58
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any design needs to include some way of stopping the energy feeding back into the rf source. to allow the rf source to be destroyed after a few experiments is wasteful and expensive. not to mention any results obtained would be dubious if the rf source was feeding back on itself
I plan to use an isolator or circulator (and monitor the reflected signal). You agree?
Peter
Looking at Roger's recent patent he has a second antenna inside the cavity. Is this used for monitoring the reflected signal? If so is this used to regulate some kind of circuit for absorbing the reflected signal before it causes damage? Is this an off the shelf item or does it need to be developed? -
#1993 by Peter Lauwer on 25 Oct, 2016 15:29
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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.
It was a well designed and built pilot experiment, I would say. I especially appreciate his well written report of the experiments, which includes most if not all of the relevant details.
From this report we can conclude though that the experiments were rather limited:
1) the sensitivity of the swinging platform was too small for the expected forces. Given the low Q, extrapolating from Brady et al, 2014, I would expect a maximum force of the order of 100 micronewtons (uN). Now his readout resolution was 13 uN, but from his figures 6-8 I estimate that he was not able to measure forces of, say, 50 uN.
2) It doesn't seem to be too difficult to take measures to reduce the thermal effects he identified. (what is missing in the report - browsing it quickly again - is whether this swinging platform is enclosed in a small cage or in a larger room, his garage maybe.)
3) No other orientations of the frustum are used.
4) Using only one mode (TE012) is rather limited (but you can say Brady et al, 2014, reported a significant force at this mode...). And I read at this forum that it is questioned whether Samsonov measured at resonance at all.
So, it is a pity that he seems to be discouraged and not has made an improved setup following this pilot experiment. I don't regards it to be a strong sign the EMdrive does not work (but on the other hand, I have neither seen reports of experiments which are strong sign it DOES work...). -
#1994 by Peter Lauwer on 25 Oct, 2016 15:47
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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.
Is this really necessary? What if you don't care about the force being a factor of 2 lower than the maximum achievable?
(Of course, the larger a possible anomalous force is compared to disturbing actions (heat, turbulence, magnetic forces), the easier it is to prove its existence.)
regards,
Peter -
#1995 by zen-in on 25 Oct, 2016 16:04
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any design needs to include some way of stopping the energy feeding back into the rf source. to allow the rf source to be destroyed after a few experiments is wasteful and expensive. not to mention any results obtained would be dubious if the rf source was feeding back on itself
I plan to use an isolator or circulator (and monitor the reflected signal). You agree?
Peter
Looking at Roger's recent patent he has a second antenna inside the cavity. Is this used for monitoring the reflected signal? If so is this used to regulate some kind of circuit for absorbing the reflected signal before it causes damage? Is this an off the shelf item or does it need to be developed?
Reflected power is measured on the feedline. The second antenna may be used to sample the power inside the cavity. At best that would be an indirect method of measuring reflected power. Circulators have been used by Yang and others to absorb the reflectd power. Resonant cavities shouldn't require circulators on the feedline if they are resonant. The fact that enough power is being reflected from the cavity to damage an amplifier indicates the cavity is not resonant at the frequency that is fed in and therefore little power is being transferred to the cavity; regardless of the claimed Q. -
#1996 by X_RaY on 25 Oct, 2016 16:53
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No. This implication is missleading i.e. this isn't the full story.
any design needs to include some way of stopping the energy feeding back into the rf source. to allow the rf source to be destroyed after a few experiments is wasteful and expensive. not to mention any results obtained would be dubious if the rf source was feeding back on itself
I plan to use an isolator or circulator (and monitor the reflected signal). You agree?
Peter
Looking at Roger's recent patent he has a second antenna inside the cavity. Is this used for monitoring the reflected signal? If so is this used to regulate some kind of circuit for absorbing the reflected signal before it causes damage? Is this an off the shelf item or does it need to be developed?
Reflected power is measured on the feedline. The second antenna may be used to sample the power inside the cavity. At best that would be an indirect method of measuring reflected power. Circulators have been used by Yang and others to absorb the reflectd power. Resonant cavities shouldn't require circulators on the feedline if they are resonant. The fact that enough power is being reflected from the cavity to damage an amplifier indicates the cavity is not resonant at the frequency that is fed in and therefore little power is being transferred to the cavity; regardless of the claimed Q.
A huge reflection coefficient has to do with an impedance mismatch. The cavity can still resonate if the geometric property fits to the frequency (n*pi/2) but at the same time it can be strong over- or under- coupled. In such a situation (K<<1 or K>>1; K=coupling factor) the reflected power is high, nevertheless the cavity may in resonance/satisfy resonance conditions. -
#1997 by meems on 25 Oct, 2016 17:49
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emdrive fan here.
Here's my latest attempt to make sense of emdrive : Consider reflection vs absorption. If a plate reflects a photon, its will take twice as much force from the photon than if it absorbed the photon. Like if a person catches a ball, it takes twice as much force to reflect the ball back at the same speed than to catch it and stop it.
The EMDrive's 2 end plates may be reflecting and absorbing photons at different rates to each other, hence they will have different radiations pressure and different forces. In other words, one plate reflects photons more, while the other absorbs them more. Hence net force, hence thrust.
This suggests that the different sizes of endplates is not necessary. An alternative is a straight cavity, with different end plate materials than absorb and reflect at different rates to each other.
thanks for any replys
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#1998 by aero on 25 Oct, 2016 18:03
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emdrive fan here.
Here's my latest attempt to make sense of emdrive : Consider reflection vs absorption. If a plate reflects a photon, its will take twice as much force from the photon than if it absorbed the photon. Like if a person catches a ball, it takes twice as much force to reflect the ball back at the same speed than to catch it and stop it.
The EMDrive's 2 end plates may be reflecting and absorbing photons at different rates to each other, hence they will have different radiations pressure and different forces. In other words, one plate reflects photons more, while the other absorbs them more. Hence net force, hence thrust.
This suggests that the different sizes of endplates is not necessary. An alternative is a straight cavity, with different end plate materials than absorb and reflect at different rates to each other.
thanks for any replys
That's more or less where I've been trying to go in calculating the forces within the cavity, except using atmospheric air molecules instead of photons. Air particles have the major advantage of being far more massive than photons hence differences in directional acceleration/rebound would be far more pronounced.
But unfortunately irregardless of what happens within the cavity, the COM issue still exists. For that idea to work the air particles or photons would need to be only an intermediary for some other mechanism which allows/causes something massive to escape. -
#1999 by WarpTech on 25 Oct, 2016 18:18
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emdrive fan here.
Here's my latest attempt to make sense of emdrive : Consider reflection vs absorption. If a plate reflects a photon, its will take twice as much force from the photon than if it absorbed the photon. Like if a person catches a ball, it takes twice as much force to reflect the ball back at the same speed than to catch it and stop it.
The EMDrive's 2 end plates may be reflecting and absorbing photons at different rates to each other, hence they will have different radiations pressure and different forces. In other words, one plate reflects photons more, while the other absorbs them more. Hence net force, hence thrust.
This suggests that the different sizes of endplates is not necessary. An alternative is a straight cavity, with different end plate materials than absorb and reflect at different rates to each other.
thanks for any replys
That's more or less where I've been trying to go in calculating the forces within the cavity, except using atmospheric air molecules instead of photons. Air particles have the major advantage of being far more massive than photons hence differences in directional acceleration/rebound would be far more pronounced.
But unfortunately irregardless of what happens within the cavity, the COM issue still exists. For that idea to work the air particles or photons would need to be only an intermediary for some other mechanism which allows/causes something massive to escape.
The location of the stored "potential" energy and the location where that energy is more readily dissipated forms a gradient inside the frustum. As long as the internal potential energy moves along this gradient to be dissipated, the frustum will move the other way. COM is not violated, regardless of the fact that nothing but heat is escaping. The heat is not a propellant, the internal gradient and the amount of energy flowing with that gradient is.
