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#2280
by
Monomorphic
on 12 May, 2016 13:51
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Maybe it would have been simpled with a magnetron from a 12V camping microwave, because no inverter needed. But it can probably achived with your 900W magnetron.
An inverter is inefficient and will be another source of heat. Plus they all have fans, which would have to be dealt with. For the price of an inverter and microwave, this 660 watt 12 v microwave is an option we have looked at here before.
http://www.roadtrucker.com/12-volt-microwave-wavebox/12-volt-dc-microwave.htm
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#2281
by
Vesc
on 12 May, 2016 13:55
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http://cannae.com/another-successful-superconducting-demo-completed/
I note:
1) the torsional pendulum is not used for Cannae's superconducting "tests"
2) batteries are not used for Cannae's superconducting "tests"
3) vacuum chamber is not used for Cannae's superconducting "tests"
in other words the same testing method is not used for Cannae's superconducting "tests" which purport to use no polymer insert as the tests with normal conductors that use polymer inserts.
Hence, the purported "no need for polymer inserts" for Cannae's superconducting "tests" is due to the different testing method.
Different testing methods ==> different results. Same story as in the tests that were nullified by Yang: when Yang did not use batteries and no polymer insert, she also obtained "thrust", when she used batteries, she obtained no thrust.
Somebody will say, but, but, but I cannot use the same testing method because 
..., well, then it is on your shoulders to show the audience that your cord is not moving the spoon (not on the shoulders of the audience that are asked to disregard that there is a cord attached to the spoon)
Despite our difference on item #2, yes I completely agree with your end statement.
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#2282
by
Rodal
on 12 May, 2016 13:55
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http://cannae.com/another-successful-superconducting-demo-completed/
I note:
1) the torsional pendulum is not used for Cannae's superconducting "tests"
2) batteries are not used for Cannae's superconducting "tests"
3) vacuum chamber is not used for Cannae's superconducting "tests"
in other words the same testing method is not used for Cannae's superconducting "tests" which purport to use no polymer insert as the tests with normal conductors that use polymer inserts.
Hence, the purported "no need for polymer inserts" for Cannae's superconducting "tests" is due to the different testing method.
Different testing methods ==> different results. Same story as in the tests that were nullified by Yang: when Yang did not use batteries and no polymer insert, she also obtained "thrust", when she used batteries, she obtained no thrust.
Somebody will say, but, but, but I cannot use the same testing method because ..., well, then it is on your shoulders to show the audience that your cord is not moving the spoon (not on the shoulders of the audience that are asked to disregard that there is a cord attached to the spoon)
I agree... with just a precision concerning the magnitude of the thrust.
If instead of a spoon, I have a cargo ship attached with a cord to my finger, and that I make it move and leaves the water 
my spectators will find it impressive.
If the thrust mesured by Cannae was of one ton, for example, as it is advanced for Shawyer superconducting drive, even with external power, it would be very interesting.
I think that when they Tested the RocketDyne F-1 motors on ground, they did not need to make a all inclusive package, with propellant on board and batteries.
Does somebody knows how much thrust they got ? It do not see it on the link.
Precisely ! I like the way you bring this back to reality.
EM Drive experimenters like to quote early experimenters like Goddard, Von Braun, the Wright Brothers.
A huge difference is that all of them: the Wright Brothers, Goddard, Von Braun, and even Project Orion (explosive driven spacecrafts) achieved FLIGHT or LIFT-OFF, while EM Drive experiments are giving microNewtons or milliNewtons, hence they cannot be compared to the Wright Brothers, Goddard, von Braun or Project Orion, because there is no flight and no lift-off in the experiments.
When testing the F-1, there was no question that it would be able to achieve lift-off.
The controversy with the EM Drive is whether the anomalous force is real.The first
problem is showing that the anomalous force is real thrust that can be used in space.
Once it is shown that this is a real thrust force that can be used in space, and that the cord makes no difference of course at that point people would not object to the use of the cord. But we are not there yet.
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#2283
by
Monomorphic
on 12 May, 2016 13:59
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http://cannae.com/another-successful-superconducting-demo-completed/
I note:
1) the torsional pendulum is not used for Cannae's superconducting "tests"
2) batteries are not used for Cannae's superconducting "tests"
3) vacuum chamber is not used for Cannae's superconducting "tests"
in other words the same testing method is not used for Cannae's superconducting "tests" which purport to use no polymer insert as the tests with normal conductors that use polymer inserts.
Hence, the purported "no need for polymer inserts" for Cannae's superconducting "tests" is due to the different testing method.
Different testing methods ==> different results. Same story as in the tests that were nullified by Yang: when Yang did not use batteries and no polymer insert, she also obtained "thrust", when she used batteries, she obtained no thrust.
Somebody will say, but, but, but I cannot use the same testing method because ..., well, then it is on your shoulders to show the audience that your cord is not moving the spoon (not on the shoulders of the audience that are asked to disregard that there is a cord attached to the spoon)
This test was not with their new battery-powered vacuum-chamber tortional pendulum. I'm curious when they plan on having that up and running.
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#2284
by
rfmwguy
on 12 May, 2016 14:00
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Maybe it would have been simpled with a magnetron from a 12V camping microwave, because no inverter needed. But it can probably achived with your 900W magnetron.
An inverter is inefficient and will be another source of heat. Plus they all have fans, which would have to be dealt with. For the price of an inverter and microwave, this 660 watt 12 v microwave is an option we have looked at here before. http://www.roadtrucker.com/12-volt-microwave-wavebox/12-volt-dc-microwave.htm
I remember looking at that as well Jamie. A self-contained system on a balance adds additional complexity (thermals, etc), usually lowers power and makes it a much higher mass to suspend and rotate.
Umbilicals are less than ideal, but it does focus the potential errors to 1 physical point(s) which I think is easier to mitigate. Know I'm sounding like a broken record, but from what I learned the past week or so, the more mass and thermal variables you have on the beam itself, the more problematic the torsion wire setup becomes...again, this is IMHO only.
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#2285
by
Rodal
on 12 May, 2016 14:02
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http://cannae.com/another-successful-superconducting-demo-completed/
I note:
1) the torsional pendulum is not used for Cannae's superconducting "tests"
2) batteries are not used for Cannae's superconducting "tests"
3) vacuum chamber is not used for Cannae's superconducting "tests"
in other words the same testing method is not used for Cannae's superconducting "tests" which purport to use no polymer insert as the tests with normal conductors that use polymer inserts.
Hence, the purported "no need for polymer inserts" for Cannae's superconducting "tests" is due to the different testing method.
Different testing methods ==> different results. Same story as in the tests that were nullified by Yang: when Yang did not use batteries and no polymer insert, she also obtained "thrust", when she used batteries, she obtained no thrust.
Somebody will say, but, but, but I cannot use the same testing method because ..., well, then it is on your shoulders to show the audience that your cord is not moving the spoon (not on the shoulders of the audience that are asked to disregard that there is a cord attached to the spoon)
This test was not with their new battery-powered vacuum-chamber tortional pendulum. I'm curious when they plan on having that up and running.
I have the impression that they are NOT planning to conduct any superconducting tests with their battery-operated torsional pendulum, which they are going to use only for the normal conducting copper cavities, instead.
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#2286
by
Rodal
on 12 May, 2016 14:11
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Meanwhile, for
a ray of hope, it has now been 3 weeks since Hackaday Aachen team reported self-assessed good results for their battery-powered rotating test tiny EM Drive with a polymer insert.
https://hackaday.io/project/5596-em-drive/log/36758-test-with-dielectric-cavity-reversedAnybody knows why the 3 week hiatus of no testing, and no news whatsoever?Hopefully we will hear some more news before they decide to test it in Space?
That would be cool
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#2287
by
Gilbertdrive
on 12 May, 2016 14:23
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About the spoon and the cord at the finger.
It is of course the man that make move the spoon attached by a cord to his finger to prove that he does not use the cord. It does not belong to the spectators to prove that the cord can help.
Also, I can understand the 2 following proofs.
1 : If an emdrive is put out of resonance, like in Stansell experiment. The magnetron works the same way. The AC wire itself should not see an internal difference, it should product the same thermal and internal magnetic effects that with the resonating Emdrive.
I do not tell that it is a definitive proof, but it eliminates at least the Pr Yang thermal coax artifact.
2 : The Reversion of the thrust by reverting the frustrum. The Magnetron should still be at the same position, with the wire unchanged, but only the frustrum reverted. The RF feed cable has to be moved, and make an angle but it is not an issue since this cable in entirely on the build.
Here also, the AC Wire cable should not see the difference. It should heat the same, it should get the same magnetic field inside.
The remaining issue that I see in both cases is the external magnetic field outside of the coax. As it was written earlier, the coax is not perfect, so, pratically, there will be some magnetic field.
This magnetic field could make a difference following the position of the frustrum, and maybe following if the frustrum is at resonnance or not.
It should be possible to mesure the magnetic field out of the coax, and to calculate the maximum interaction with the build itself. If it is several orders of magnitude lower than the thrust, I think it start to be a strong proof that the thrust is not from the coax cable.
But it seems to me that in Cannae reversion, they rotated the entire setup. So, there is no elimination at all of the coax artifact. If they rotate the coax cable of 180°, the reversion of thrust just proves nothing about the coax artifact.
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#2288
by
Gilbertdrive
on 12 May, 2016 14:44
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Maybe it would have been simpled with a magnetron from a 12V camping microwave, because no inverter needed. But it can probably achived with your 900W magnetron.
An inverter is inefficient and will be another source of heat. Plus they all have fans, which would have to be dealt with. For the price of an inverter and microwave, this 660 watt 12 v microwave is an option we have looked at here before. http://www.roadtrucker.com/12-volt-microwave-wavebox/12-volt-dc-microwave.htm
I remember looking at that as well Jamie. A self-contained system on a balance adds additional complexity (thermals, etc), usually lowers power and makes it a much higher mass to suspend and rotate.
Umbilicals are less than ideal, but it does focus the potential errors to 1 physical point(s) which I think is easier to mitigate. Know I'm sounding like a broken record, but from what I learned the past week or so, the more mass and thermal variables you have on the beam itself, the more problematic the torsion wire setup becomes...again, this is IMHO only.
True for the inverter. It remains that using Lipo designed for modelism, you can have 8000 mAh 11.1V that weight about 500g and can be decharged at 40C, around 3200W, and should fit the 12V magnetron.
The thermal added would be far less than the thermal effects already present because of the magnetron. It should have been OK with the 660W 12V microwave. But, now that you made your setup around the 900W Magnetron, I understand that you prefer to go on.
Also, I am perfectly conscient that you, Seeshell, and other DIYers are the important part. I am just behind my keyboard, trying to think about your builds, asking you about doing that or that, and not doing it myself. So, I want you to be conscient that, despite all my objections or suggetions, I have much admiration for your work.
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#2289
by
OttO
on 12 May, 2016 14:44
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Article appears to be behind a paywall. Could not download it. Would appreciate a download weblink if you have one.
Questions, if you have read the article:
1) Isn't the article about optocavities at optical frequencies rather than microwave frequencies?
2) What material are they addressing for the reflecting walls of the optocavity?
Thanks
You could try this link (it is not the same paper but the same authors and the same subject:
Photon mass drag and the momentum of light in a mediumhttp://arxiv.org/pdf/1603.07224
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#2290
by
Rodal
on 12 May, 2016 14:51
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Article appears to be behind a paywall. Could not download it. Would appreciate a download weblink if you have one.
Questions, if you have read the article:
1) Isn't the article about optocavities at optical frequencies rather than microwave frequencies?
2) What material are they addressing for the reflecting walls of the optocavity?
Thanks
You could try this link (it is not the same paper but the same authors and the same subject:
Photon mass drag and the momentum of light in a medium
http://arxiv.org/pdf/1603.07224
OK, thanks. I note:
1) The authors discuss the momentum of light in a transparent material
2) The word conductor, or good conductor, do not appear in the paper
3) The word copper does not appear in the paper
4) The paper deals with dielectrics at optical frequencies
5) Paper may be relevant to those using dielectrics at optical frequencies (as such tests have been proposed, and may be carried out).
6) Or I maybe missing something, if others can relate this to copper EM Drive without dielectric inserts, in which case would love to learn what I missed.
Thanks
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#2291
by
Monomorphic
on 12 May, 2016 15:33
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#2292
by
Rodal
on 12 May, 2016 16:27
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Another reason tapered waveguides are interesting:
TAPERED WAVEGUIDES EMULATE ANISOTROPIC MATERIALS WITH APPLICATION TO OPTICAL CLOAKING
Anisotropic Metamaterials Emulated by TaperedWaveguides: Application to Optical Cloaking
Igor I. Smolyaninov,1 Vera N. Smolyaninova,2 Alexander V. Kildishev,3 and Vladimir M. Shalaev3
We demonstrate that metamaterial devices requiring anisotropic dielectric permittivity and magnetic
permeability may be emulated by specially designed tapered waveguides. This approach leads to low-loss,
broadband performance.
By using an axisymmetric waveguide between a planar gold film and a gold-coated spherical lens, we experimentally demonstrated a broadband optical cloaking effect in the visible frequency range for an object, which is 2 orders of magnitude larger than the wavelength of the incident light.
Filling the specifically shaped waveguide domain with an anisotropic dielectric allows for independent control over the effective magnetic and electric propertieshttps://engineering.purdue.edu/~shalaev/Publication_list_files/PRL%20Cloak.pdfThe author is a well-known and highly cited Professor at University of Maryland having a large RG score, placing him
higher than 97.5% of ResearchGate members
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#2293
by
zen-in
on 12 May, 2016 17:01
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Maybe it would have been simpled with a magnetron from a 12V camping microwave, because no inverter needed. But it can probably achived with your 900W magnetron.
An inverter is inefficient and will be another source of heat. Plus they all have fans, which would have to be dealt with. For the price of an inverter and microwave, this 660 watt 12 v microwave is an option we have looked at here before. http://www.roadtrucker.com/12-volt-microwave-wavebox/12-volt-dc-microwave.htm
I wouldn't be surprised if that "Trucker's microwave" had an inverter and fan inside. Magnetrons require a high voltage.
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#2294
by
Gilbertdrive
on 12 May, 2016 17:17
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Maybe it would have been simpled with a magnetron from a 12V camping microwave, because no inverter needed. But it can probably achived with your 900W magnetron.
An inverter is inefficient and will be another source of heat. Plus they all have fans, which would have to be dealt with. For the price of an inverter and microwave, this 660 watt 12 v microwave is an option we have looked at here before. http://www.roadtrucker.com/12-volt-microwave-wavebox/12-volt-dc-microwave.htm
I wouldn't be surprised if that "Trucker's microwave" had an inverter and fan inside. Magnetrons require a high voltage.
But even 110V microwaves have an inverter. The magnetrons are not directly fed with 110V AFAIK.
One inverter from 12V to several thousands of volt, IMHO, will be be more efficient that 2 inverters, one from 12V to 110V, and another one from 110 to thousands of volts.
The problem would be if the trucker's microwave was already using 2 inverters because of lazy engineers
EDIT. They are so proud to explain that it is a real 12V microwave that I hope it is not just a 110V microwave+ second inverter.
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#2295
by
X_RaY
on 12 May, 2016 18:43
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Got an email back from Triarchy about using their USB spectrum analyser to measure s11 and s21.
"TSA4G1 can work with TSG4G1 to measure the S11 and S21, it shall use external directional coupler to work with S11."
The TSG4G1 is their $349 synthesized signal generator. http://www.triarchytech.com/product_SG4.html
So for the price of the USB spectrum analyser, $530 and the signal generator, $349, one could have a full featured RF test station that normally costs ~$8,000.
For example, this is what NASA has used: http://www.keysight.com/en/pcx-x205205/fieldfox-and-hsa-handheld-spectrum-analyzers?cc=US&lc=eng
The setup of these two devices with an simple external directional coupler leads to some kind of
scalar network analyzer (amplitude over frequency) while the keysight instrument is a full
vector network analyzer and delivers
amplitude and phase of the signal
over frequrency.
Synchronization of the devices could be a hard job. Therefore the software of a professional VNA is also highly recommend. Of course it's much more expensive, quality costs
Nevertheless I like the idea in general because of the low costs.
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#2296
by
Rodal
on 12 May, 2016 20:40
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...
Hence my contention that it is worth exploring whether the Abraham/Minkowski controversy has any bearing on this problem.
R.
...
(**) Is there a difference between copper and vacuum? Yes, the important difference is in the imaginary parts of the permittivity, it is the loss tangent (tan δ) that has a huge value, while the vacuum (as far as we know) does not have a significant value of the loss tangent. Thus the difference between them at microwave frequencies is not in the real part of the index of refraction, but it is instead in the imaginary part of the index of refraction.
What is the practical consequence of this difference? It is the power loss in the copper: HEAT, as the power is dissipated into HEAT.
If somebody can explain how the power loss in the copper can be translated into momentum to the cavity (other than by thermal effects like: thermal convection, thermal radiation and thermal expansion), now that would be interesting!
Further to this interesting subject (Abraham Minkowski controversy) and its relation to EM Drive with air or vacuum and the metal being copper
Mansuripur (who had claimed a few years ago that he had resolved the Abraham-Minkowski controversy, which I don't agree with because
such a controversy can only be resolved by experiments and not theoretically, because it pertains to the constitutive properties of materials)did examine the situation of a conductive metallic mirror reflecting inside a transparent medium (which could be air or vacuum, or any transparent gas), he does consider a monochromatic plane wave like you, but unlike you, he does take into account the complex properties of the conductor:
Whence the Minkowski Momentum?
Masud Mansuripur† and Armis R. Zakharian‡
Optics Communications 283, 3557-3563 (2010)]
http://arxiv.org/abs/1207.6676Concluding remarks. In this paper we examined the radiation pressure experienced by an absorber/reflector
immersed in a transparent, homogeneous, isotropic medium...
When the relative values are such that, on the right-hand side of Eq.(9), the contribution of 1 to the denominator is negligible (e.g., when 2 has a large imaginary part, as in good metallic reflectors), the transferred momentum per incident photon is seen to become simply proportional to 1 (or, for a non-magnetic host, to n1).
Under such circumstances, one is tempted to say that the photons inside the transparent host carry the Minkowski
momentum, although the proper interpretation is that a reduced impedance-mismatch has enhanced the coupling of the incident photons to the absorber/reflector.
Please note that Mansuripur's conclusions agree with the ones that I previously stated (*):
when one has a good metallic reflector (like copper) which has a large imaginary part of the electric permittivity compared to its real part (large tan delta resulting in heat dissipation losses in the copper),
then the transferred momentum is simply proportional to the properties of the medium it is immersed in: which are the properties of air or vacuum, for the EM Drive.--------------
(*) I am not convinced by his analysis because 1) his simplification of using monochromatic
plane waves (no electromagnetic field along direction of propagation) hitting a conductive medium is too simplistic in comparison with the EM Drive., 2) He uses time average of the Poynting vector and other quantities. 3) He does not formally solve the partial differential equations and
boundary conditions, 4) he uses Finite Difference modeling, which does NOT satisfy conservation of energy equation (something which I will show and prove when I have a chance),
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#2297
by
rfmwguy
on 12 May, 2016 21:46
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***General Emdrive Thoughts***
Looks like the TMRO 9.16 episode uploaded to youtube late Sunday evening has close to 3900 views already. Looks like that is roughly 1000 views a day, higher in comparison to a lot of their other videos.
Its interesting to me that despite denouncements from many quarters, emdrive continues to be popular. I started interest in it a couple of years ago and am surprised at the increasing popularity. Really assumed it was a very narrow interest group without a wider appeal when I first started.
Non-commercially speaking, anything that get 1,000 video hits or views per day seems to me to be a rather hot interest topic...the public is notoriously fickle and move to something else quickly, so it may change...But for anyone in the space biz, this is sending out a message, IMHO...After more than a decade, the emdrive concept continues to have a strong public interest level and following.
Views here of T7 are approaching 300,000 in just a few months. An institution or space concern announcing publicly they were going to investigate and get to the bottom of this concept (once and for all) certainly have enough evidence by now that there is on-going interest globally.
Look at Paul Stansell's emdrive experiment, an international finalist in Intel's International Science and Engineering Fair. Paul got past his own school, his own region or district, his own country and finally his own continent of Africa to win a trip to the USA. Somewhere, somebody believed in him. Sometimes it pays to dream and think outside the box and away from the classical textbooks.
My opinion only, not representing NSF or anyone else on these threads...
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#2298
by
FattyLumpkin
on 12 May, 2016 22:00
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Re complications (heating, cooling et al.)with the use of various RF components, is it not true that "cavity load" time intervals are less than 1 second in duration. If memory serves did not EWL report "immediate" responses with the "turning on" of the RF? (recognizing that there was pre-tuning of frequency prior to a data test run). FL
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#2299
by
rfmwguy
on 12 May, 2016 22:12
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Re complications (heating, cooling et al.)with the use of various RF components, is it not true that "cavity load" time intervals are less than 1 second in duration. If memory serves did not EWL report "immediate" responses with the "turning on" of the RF? (recognizing that there was pre-tuning of frequency prior to a data test run). FL
According to Dr Rodal's 2014 paper on researchgate, the buckling of <0.83 mm copper sidewalls starts in less than a second and at 30 watts IIRC. Mag lock is usually a second or two at the most. Solid state power source would be "immediate" on unless there was a purposeful delay in the final amp. I believe cavity load time is near instantaneous and dependent on the source.
..., well, then it is on your shoulders to show the audience that your cord is not moving the spoon (not on the shoulders of the audience that are asked to disregard that there is a cord attached to the spoon)
my spectators will find it impressive.
