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#2600 by WarpTech on 15 Feb, 2017 05:13
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Just to ensure Guido Fetta's conference paper is known here;
Guido P. Fetta,. "Numerical and Experimental Results for a Novel Propulsion Technology Requiring no On-Board Propellant", 50th AIAA/ASME/SAE/ASEE Joint Propulsion Conference, AIAA Propulsion and Energy Forum, (AIAA 2014-3853)
http://dx.doi.org/10.2514/6.2014-3853
I like that his device employs TM010
Does anyone have the actual paper? This is just a link to the website.
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#2601 by as58 on 15 Feb, 2017 06:29
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BTW, your time delay on startup and turnoff may be due to instrumentation processor or A-to-D time delays. My Texmate 320 computerized panel meter with a 24 bit load cell amplifier that I used for my MLT-2004 test series took about 0.8 second before it would start reacting to a signal input change and it would take another ~0.8 second before it would show a change from an on-state condition. Very annoying until I figured out what was causing it. Not sure if that is what you are dealing with now, but you need to check it out.
The time delay looks to be much too long (>10 s) for this explanation to work. -
#2602 by Monomorphic on 15 Feb, 2017 10:37
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BTW, your time delay on startup and turnoff may be due to instrumentation processor or A-to-D time delays. My Texmate 320 computerized panel meter with a 24 bit load cell amplifier that I used for my MLT-2004 test series took about 0.8 second before it would start reacting to a signal input change and it would take another ~0.8 second before it would show a change from an on-state condition. Very annoying until I figured out what was causing it. Not sure if that is what you are dealing with now, but you need to check it out.
The time delay looks to be much too long (>10 s) for this explanation to work.
This few tests is not a large enough sample to say for sure exactly what is happening here. There could be a down oscillation at the moment RF was applied that the anamalous force has to fight against before registering on the equipment. I need more tests runs to compare. I'm also looking into improving the noise level with magnetic dampening. -
#2603 by RERT on 15 Feb, 2017 11:39
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Monomorphic -
It would be helpful to see tap test results for the configuration on which you measured the anomaly. With data from two distinct taps of different strengths, I think I could fit the damping factor and moment of inertia and have a go at extracting the 'instantaneous' force profile during the test. -
#2604 by Monomorphic on 15 Feb, 2017 12:17
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Monomorphic -
It would be helpful to see tap test results for the configuration on which you measured the anomaly. With data from two distinct taps of different strengths, I think I could fit the damping factor and moment of inertia and have a go at extracting the 'instantaneous' force profile during the test.
I plan on doing this soon. The problem is knowing what strength the tap is. Does that matter for your purposes or will two light taps of different magnitude from a pen work? -
#2605 by Rodal on 15 Feb, 2017 12:24
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Just to ensure Guido Fetta's conference paper is known here;
Guido P. Fetta,. "Numerical and Experimental Results for a Novel Propulsion Technology Requiring no On-Board Propellant", 50th AIAA/ASME/SAE/ASEE Joint Propulsion Conference, AIAA Propulsion and Energy Forum, (AIAA 2014-3853)
http://dx.doi.org/10.2514/6.2014-3853
I like that his device employs TM010
Does anyone have the actual paper? This is just a link to the website.
This 2014 conference paper was discussed several threads ago (maybe in a 2014 or 2015 thread). I have it in an old computer, but I can't find it at the moment. Maybe somebody can search all NSF EM Drive threads (good luck with this search function
).
Anyway, in this post https://forum.nasaspaceflight.com/index.php?topic=39214.msg1546438#msg1546438 I show that Fetta's analysis is wrong as he does not include all terms in the conservation of momentum equation to define a force.
Amazingly, Fetta forgets to take into account the derivative with respect to time of the Poynting vector in his definition of a force, hence it is not surprise that his incorrect definition of force is not zero for pure electromagnetic resonance in a closed cavity.
In previous threads we have shown that for the EM Drive, the derivative with respect to time of the Poynting vector is not zero, on the contrary, it is just as important as the force component calculated from the stress tensor, hence it has to be taken into account in the definition of the force.
In undergraduate courses it is taught that the force (f) is given by both the divergence of the stress tensor (σ) minus the derivative with respect to time of the Poynting vector (S)
3) Guido Fetta, in his paper
Guido P. Fetta. "Numerical and Experimental Results for a Novel Propulsion Technology Requiring no On-Board Propellant", 50th AIAA/ASME/SAE/ASEE Joint Propulsion Conference, Propulsion and Energy Forum,
http://dx.doi.org/10.2514/6.2014-3853
calculates the force, in Equations (4) and (5) of the above mentioned paper as being due to the time-averaged integral of the (negative of the) stress tensor component
- σ3 = u - p
= u - εo E2
= ((1/μo) B2 - εo E2)/2
= (μo H2 - εo E2)/2
(See https://forum.nasaspaceflight.com/index.php?topic=39214.msg1526577#msg1526577: this is the so-called "Lagrangian Density", which is an invariant under Lorentz transformations as well as an invariant under rotations).
This is wrong for general unsteady behavior, as in radio-frequency excitation of the EM Drive, the force should have been defined also taking into account the derivative with respect to time of the Poynting vector.
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#2606 by rfmwguy on 15 Feb, 2017 13:46
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You and your compatriot are quite mistaken. Perhaps you should defer to those who have actually done EmDrive experimentation. I encourage Jamie to reduce, not increase dampening. But this of course is up to him. He should avoid needless speculation by those with only a keyboard and not hands on experience working with this device.
Damping makes no sense as the cause of the delay. To start with, damping is zero when velocity is zero, so it can't have a stiction-like effect (also stiction doesn't make sense for this setup.)
Congrats on a bonifide emdrive run! Axial insertion is probably the way to go. Glad Q was so high with foil! Good experimental find. I'd agree swing mass dampening is your culprit on persistence and startup delay. A smaller paddle should work or lift it partially out of bath. You will notice Y axis LDS was showing no signs of thermal lift. At your lower power, heating of the frustum should be minimal. May not register on IR.Do have a concern why it takes more than 10 sec for the force to appear and it lingers for around the same time after power was removed.
Thanks Phil.
Perhaps this is because I am still very over damped. I am going to reduce the size of the dampening paddle. I may even need to switch to a lighter weight oil. I'm using gear oil right now and it is VERY viscous. This was all necessary when testing with the heavy and noisy magnetron, but now that is gone, a little more finesse is required...
Also, the system is clearly underdamped, not overdamped based on the oscillations after power off. A tap test would demonstrate this clearly. Reducing damping still would make for interesting additional data, but the current damping looks good.
More data is obviously needed, but my hypothesis would be a thermal effect where heating takes some time to diffuse to wherever the portion is that causes the motion (or it takes time for a convection current to get set up.) Similar effects explain the delay at the end as well.
The oscillations after power off appear to be around a decaying point, supporting the hypothesis that this may be purely thermal.
p.s. I've learned to be just as bold and arrogant sounding as others here on the sidelines. -
#2607 by Peter Lauwer on 15 Feb, 2017 13:54
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Hi Jamie,Monomorphic -
It would be helpful to see tap test results for the configuration on which you measured the anomaly. With data from two distinct taps of different strengths, I think I could fit the damping factor and moment of inertia and have a go at extracting the 'instantaneous' force profile during the test.
I plan on doing this soon. The problem is knowing what strength the tap is. Does that matter for your purposes or will two light taps of different magnitude from a pen work?
I think it is better to do a "magnetic tap". If you attach (temporarily) a small bar magnet to the balance arm and place a coil opposite to it, you can apply a step-like force in the horizontal plane. And from the overshoot (or not) you can estimate what the relative damping is.
Also, if you already have this configuration, you can use it to measure the frequency response of the torsion balance. You need a function generator then with low enough frequency, say 10 mHz. And you might need to amplify the signal (and you need to check whether the amplitude of the current remains constant over the frequency range.
Below I give an example of a response determined in this way.
Succes, your experiment looks great!
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#2608 by Notsosureofit on 15 Feb, 2017 13:57
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Just passing through..is this any help ?
http://www.research-equipment.com/viscosity%20chart.htmlThanks Phil.
Perhaps this is because I am still very over damped. I am going to reduce the size of the dampening paddle. I may even need to switch to a lighter weight oil. I'm using gear oil right now and it is VERY viscous. This was all necessary when testing with the heavy and noisy magnetron, but now that is gone, a little more finesse is required...
Many motor oils have dilitant additives.
https://books.google.com/books?id=Qw9gwzzf4SAC&pg=PA51&lpg=PA51&dq=Thixotropic+motor+oils&source=bl&ots=HogA03KSph&sig=PhTu1zwqZ3hB8-JaDew87NWCvAU&hl=en&sa=X&ved=0ahUKEwjvlumGrpLSAhUL9YMKHRJvDXUQ6AEILDAD#v=onepage&q=Thixotropic%20motor%20oils&f=false
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#2609 by Peter Lauwer on 15 Feb, 2017 14:01
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Here are a couple of the very first powered tests. I have what appears to be an anomalous "forward" thrust signature.
I've repeated tests several times now with similar results.
I'm not entirely sure where I should measure the trace for most accurate displacement (perhaps someone can chime in). Average noise peak to displacement peak is what I am using now.
Using 0.1440mN/mA for my torsional pendulum I get the following:
Holding maximum resonance at 1 Watt, force measured was 0.01296mN (12.96uN). 12.96mN/kW
For the second run, I did a frequency sweep of the resonance bandwidth. Measured force was 0.00684mN (6.84uN). 6.84mN/kW
Shawyer's prediction via TheTraveler's spreadsheet for 1W is 0.361mN. I'm not sure how this compares to other theory's predictions.
The delay of ~20 s does indeed make one think of a heat-effect as the cause for the deflection. How about putting isolation around the parts which heat up most? (the amp, etc.) -
#2610 by Rodal on 15 Feb, 2017 14:03
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..
I love the fact that Monomorphic is doing this with solid-state, battery-self-contained, using only 1 watt of power, and that he gets repeatable results.
Succes, your experiment looks great!
I hope that Monomorphic will continue testing at low power (1 watt), to minimize heat production and that he will eventually test with insulation on both flat ends, and reversing the direction of the EM Drive, and other suggestions made in the forum.
Performing such a continuing systematic series of tests, testing all possible artifacts (rather than saying hey: I got a force and then dismantling the setup without testing for artifacts) is the way to finally understand what is going on. To finally answer all the criticisms.
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#2611 by Peter Lauwer on 15 Feb, 2017 14:13
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....
The interesting thing here is that Monomorphic has only one (1) watt of power input into this !
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1 W into the cavity, indeed. But I guess the total power consumption is at least 10 W (the wifi amp has ~10% efficiency). -
#2612 by Rodal on 15 Feb, 2017 14:16
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....
The interesting thing here is that Monomorphic has only one (1) watt of power input into this !
...
1 W into the cavity, indeed. But I guess the total power consumption is at least 10 W (the wifi amp has ~10% efficiency).
Much better than pumping hundreds of watts through power cables into an exposed magnetron to ambient air:
Great progress !
Also it was not too long ago when Prof. Yang appeared to defenestrate her live's work with a "null-result" battery self-enclosed test that appeared to indicate that the force in her previous tests was due to thermal expansion of the power cable.
Now Monomorphic is showing results with a battery self-enclosed set-up !
And to have a test in Space, having a solid-state battery-powered, few watts EM Drive is definitely the way to go ! -
#2613 by Rodal on 15 Feb, 2017 14:47
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...
Another advantage is that the idea that our local ruler is contracting, logically leads to a nearly "constant" expansion over vast distances, 6.8 nm/m-cen, which we interpret as the Hubble Constant. Why would a "big bang" lead to a constant rate over such vast distances? Why are "we" at the center of the expansion, i.e., why is it isotropic? This model resolves these questions logically, in a straight forward manner.
Todd
One can also argue that:
1) In General Relativity, length, and hence surface and volume, are all observer dependent and hence not invariant like mass.
2) In a conformally invariant theory (https://en.wikipedia.org/wiki/Conformal_gravity) if the measured inertial mass of a particle in a given spacetime metric gik is m, then in a conformal transformation Ω2 gik of this metric, with Ω a function of spacetime, the inertial mass should become m/Ω. An issue with conformal gravity theories, due to the higher derivatives, is the typical presence of ghosts (https://en.wikipedia.org/wiki/Faddeev%E2%80%93Popov_ghost#General_ghosts_in_theoretical_physics), which point to instabilities of the quantum version of the theory. It is not known whether there might be a solution to the ghost problem. There is a general belief that they cannot be consistently quantized. This is disputed by Mannheim in the UK. This maybe of interest for propellant-less space propulsion theories because the theory proposed by Woodward contains such higher derivatives, and Woodward's theory has been based on Hoyle-Narlikar theory which is conformally invariant, but to my knowledge, neither Woodward nor Fearn addressed this issue of ghosts.
. -
#2614 by RERT on 15 Feb, 2017 15:50
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Monomorphic -
It would be helpful to see tap test results for the configuration on which you measured the anomaly. With data from two distinct taps of different strengths, I think I could fit the damping factor and moment of inertia and have a go at extracting the 'instantaneous' force profile during the test.
I plan on doing this soon. The problem is knowing what strength the tap is. Does that matter for your purposes or will two light taps of different magnitude from a pen work?
Of preference the taps should produce a deflection broadly in-line with the deflections you are measuring. 10X wold make me nervous, but if that's all that's possible then so be it.
I'm sure I can do a fit from just one tap, but the second tap will show if the fit is capturing a reasonable estimate of physical parameters or is just wiggling a trunk, so to speak. That requires the two taps to be distinct, one say 2X the other.
I recall previously you 'tapped' with a magnet outside the enclosure which produced some spectacularly fine results, due presumably to the lack of air movement near the 'pen'. If you can do the above taps in that way it would be great.
BTW while I'm here, you spoke before of changing the paddles to change the damping - might it be easier to just remove some oil? -
#2615 by WarpTech on 15 Feb, 2017 16:58
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...
Another advantage is that the idea that our local ruler is contracting, logically leads to a nearly "constant" expansion over vast distances, 6.8 nm/m-cen, which we interpret as the Hubble Constant. Why would a "big bang" lead to a constant rate over such vast distances? Why are "we" at the center of the expansion, i.e., why is it isotropic? This model resolves these questions logically, in a straight forward manner.
Todd
One can also argue that:
1) In General Relativity, length, and hence surface and volume, are all observer dependent and hence not invariant like mass.
2) In a conformally invariant theory (https://en.wikipedia.org/wiki/Conformal_gravity) if the measured inertial mass of a particle in a given spacetime metric gik is m, then in a conformal transformation Ω2 gik of this metric, with Ω a function of spacetime, the inertial mass should become m/Ω. An issue with conformal gravity theories, due to the higher derivatives, is the typical presence of ghosts (https://en.wikipedia.org/wiki/Faddeev%E2%80%93Popov_ghost#General_ghosts_in_theoretical_physics), which point to instabilities of the quantum version of the theory. It is not known whether there might be a solution to the ghost problem. There is a general belief that they cannot be consistently quantized. This is disputed by Mannheim in the UK. This maybe of interest for propellant-less space propulsion theories because the theory proposed by Woodward contains such higher derivatives, and Woodward's theory has been based on Hoyle-Narlikar theory which is conformally invariant, but to my knowledge, neither Woodward nor Fearn addressed this issue of ghosts.
.
The Wikipedia article doesn't cover the PV conformal metric. Which is conformally flat, like Minkowski space-time, but with a Schwarzschild-like coefficients;
i.e., g00 = -1/g11
ds2 = -c02dt2/K + K*(dr2 + dΩ2)
Also, in my model I end up with the Klein-Gordon equation and the Goldstone boson. The same as that used to derive the Higgs field.
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#2616 by Rodal on 15 Feb, 2017 17:26
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...
Another advantage is that the idea that our local ruler is contracting, logically leads to a nearly "constant" expansion over vast distances, 6.8 nm/m-cen, which we interpret as the Hubble Constant. Why would a "big bang" lead to a constant rate over such vast distances? Why are "we" at the center of the expansion, i.e., why is it isotropic? This model resolves these questions logically, in a straight forward manner.
Todd
One can also argue that:
1) In General Relativity, length, and hence surface and volume, are all observer dependent and hence not invariant like mass.
2) In a conformally invariant theory (https://en.wikipedia.org/wiki/Conformal_gravity) if the measured inertial mass of a particle in a given spacetime metric gik is m, then in a conformal transformation Ω2 gik of this metric, with Ω a function of spacetime, the inertial mass should become m/Ω. An issue with conformal gravity theories, due to the higher derivatives, is the typical presence of ghosts (https://en.wikipedia.org/wiki/Faddeev%E2%80%93Popov_ghost#General_ghosts_in_theoretical_physics), which point to instabilities of the quantum version of the theory. It is not known whether there might be a solution to the ghost problem. There is a general belief that they cannot be consistently quantized. This is disputed by Mannheim in the UK. This maybe of interest for propellant-less space propulsion theories because the theory proposed by Woodward contains such higher derivatives, and Woodward's theory has been based on Hoyle-Narlikar theory which is conformally invariant, but to my knowledge, neither Woodward nor Fearn addressed this issue of ghosts.
.
The Wikipedia article doesn't cover the PV conformal metric. Which is conformally flat, like Minkowski space-time, but with a Schwarzschild-like coefficients;
i.e., g00 = -1/g11
ds2 = -c02dt2/K + K*(dr2 + dΩ2)
Also, in my model I end up with the Klein-Gordon equation and the Goldstone boson. The same as that used to derive the Higgs field.
Good point. I guess that Fearn and Woodward would also answer that their theory only refers to flat (Minkowski) space + time, and cite the recent measurement of the spatial flatness of the universe at cosmic scales by the WMAP survey.
However, Minkowski's spacetime is not a solution to Einstein's field equations when there is a non-vanishing cosmological constant ...
So, this (Minkowski's spacetime is not a solution to Einstein's field equations for non-vanishing cosmological constant) appears to force one into opposition to the accelerating expansion of the Universe, if one assumes Minkowski flat-space + time.
If you have a theory that assumes Minkowski flat-space + time, it looks like you are forced into your viewpoint opposing the accelerating expansion of the Universe viewpoint. -
#2617 by WarpTech on 15 Feb, 2017 18:17
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...
Another advantage is that the idea that our local ruler is contracting, logically leads to a nearly "constant" expansion over vast distances, 6.8 nm/m-cen, which we interpret as the Hubble Constant. Why would a "big bang" lead to a constant rate over such vast distances? Why are "we" at the center of the expansion, i.e., why is it isotropic? This model resolves these questions logically, in a straight forward manner.
Todd
One can also argue that:
1) In General Relativity, length, and hence surface and volume, are all observer dependent and hence not invariant like mass.
2) In a conformally invariant theory (https://en.wikipedia.org/wiki/Conformal_gravity) if the measured inertial mass of a particle in a given spacetime metric gik is m, then in a conformal transformation Ω2 gik of this metric, with Ω a function of spacetime, the inertial mass should become m/Ω. An issue with conformal gravity theories, due to the higher derivatives, is the typical presence of ghosts (https://en.wikipedia.org/wiki/Faddeev%E2%80%93Popov_ghost#General_ghosts_in_theoretical_physics), which point to instabilities of the quantum version of the theory. It is not known whether there might be a solution to the ghost problem. There is a general belief that they cannot be consistently quantized. This is disputed by Mannheim in the UK. This maybe of interest for propellant-less space propulsion theories because the theory proposed by Woodward contains such higher derivatives, and Woodward's theory has been based on Hoyle-Narlikar theory which is conformally invariant, but to my knowledge, neither Woodward nor Fearn addressed this issue of ghosts.
.
The Wikipedia article doesn't cover the PV conformal metric. Which is conformally flat, like Minkowski space-time, but with a Schwarzschild-like coefficients;
i.e., g00 = -1/g11
ds2 = -c02dt2/K + K*(dr2 + dΩ2)
Also, in my model I end up with the Klein-Gordon equation and the Goldstone boson. The same as that used to derive the Higgs field.
Good point. I guess that Fearn and Woodward would also answer that their theory only refers to flat (Minkowski) space + time, and cite the recent measurement of the spatial flatness of the universe at cosmic scales by the WMAP survey.
However, Minkowski's spacetime is not a solution to Einstein's field equations when there is a non-vanishing cosmological constant ...
So, this (Minkowski's spacetime is not a solution to Einstein's field equations for non-vanishing cosmological constant) appears to force one into opposition to the accelerating expansion of the Universe, if one assumes Minkowski flat-space + time.
If you have a theory that assumes Minkowski flat-space + time, it looks like you are forced into your viewpoint opposing the accelerating expansion of the Universe viewpoint.
Actually, I have 4 solutions to "my" time-independent Lagrangian density equation.
Cartesian coordinates leads to the equation of a line. This solution matches GR.
Spherical coordinates lead to the Schwarzschild solution and the Reissner-Nordstrom solution when equated to an EM force. This solution matches GR.
In cylindrical coordinates, the situation of an infinitely long massive wire, whose solution also matches that of GR.
To my understanding, Minkowski space-time in Spherical coordinates is just the Schwarzschild solution with "constant" coefficients over each concentric radial sphere. That is what I am referring to as conformally flat;
ds2 = -c02dt2/K + K*(dr2 + dΩ2)
Where K is only a function of radius "r" from the origin, in this case.
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#2618 by Notsosureofit on 15 Feb, 2017 18:58
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#2619 by WarpTech on 15 Feb, 2017 21:46
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FYI:
https://phys.org/news/2017-02-method-levitate-variety.html#nRlv
"In the experiment, the bottom copper plate was kept at room temperature while a stainless steel cylinder filled with liquid nitrogen kept at negative 300 degrees Fahrenheit served as the top plate. The upward flow of heat from the warm to the cold plate kept the particles suspended indefinitely."
Now THIS is confirmation of my model, because there is no difference between a temperature gradient in a vacuum versus my Quantum Vacuum model, and a gravitational gradient as described in my model. Excellent!
).
Perhaps this is because I am still very over damped. I am going to reduce the size of the dampening paddle. I may even need to switch to a lighter weight oil. I'm using gear oil right now and it is VERY viscous. This was all necessary when testing with the heavy and noisy magnetron, but now that is gone, a little more finesse is required...
I've repeated tests several times now with similar results. 