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#2700 by zellerium on 24 May, 2016 03:50
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https://forum.nasaspaceflight.com/index.php?topic=39004.msg1491956#msg1491956My antenna into the cavity. Directly and into the waveguides.
I'm referring to rfmwguy's VNA antenna setup. I believe he said you fabricated it. I tore down an extra identical magnetron I had and am curious how to best connect the coax.
This was shown by zellerium some times ago...
The antenna we built by cutting off the top of the maggie and soldering an SMA panel to the tap wire was very finicky. Meaning sometimes it would work perfectly and sometimes it wouldn't show any resonance. Sometimes it was somewhere in between... Some of this may have been exact alignment of the antenna in the waveguide, the magnet kept it mounted but not always centered. It also may have been the old VNA we were using, I haven't gone back to try the old antenna with the new VNA. Apparently the old VNA short circuit calibrator is homemade because kids kept breaking them and someone got tired of buying them.
We were lucky to be lent a professionally tuned antenna which is much more consistent.
Apparently the tuned antennas cost a few grand and can be bought off the shelf.
However I am certain I have found the same resonance (both S11 magnitude, quality and location) with both antenna at different times.
What about this: If one were to measure the steady state temperature of a magnetron feeding a resonant cavity, would the magnitude of the temperature be able to indicate the magnetude of mismatch?
If one were to run a magnetron at lower power during such tests (say 10-50 W RF) would it have the same frequency distribution as it would at full power?
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#2701 by Star One on 24 May, 2016 05:25
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As a lay person in all this I didn't realise there was other competing theories in this area. I was aware of the many worlds & the standard Copenhagen versions but not this particular way of thinking.Any relevance to this thread as this represents some new but also old thinking on the behaviour of particles in this particular case photons.
http://www.wired.com/2016/05/new-support-alternative-quantum-view/
Very relevant to me; I was/am researching actuation applications of parametric instabilities in electroactive polymer gels before the EM Drive distracted me. I can't get away from similarities. Last couple days I've watched a few video on Casimir, dark energy and inflation and find the dynamic Casimir effect experiment, modulating a microwave cavity with a sqid to produce particles, seems to be parametric instability/Faraday waves. And there are similarities to optical refrigeration and optomechanical excitation, which I believe involve the dynamics at work with the EM Drive.
Anyways, here are some great videos that illustrate the pilot-wave concept, even if they don't elucidate the quantum-vacuum as well. A play list featuring (of course) Yves Couder's classics:
For some reason, I can't get the you-tube playlist with the Couder vids to show up. If you want to see more, search you-tube for "Yves Couder". Its worth the bother.
Another video at a site with lots of eye-candy:
http://gfm.aps.org/meetings/dfd-2015/55f71c7b69702d060d750500
Thinking about the metaphor, the wave-tank is the vacuum. The droplets represent bosons and fermions. But how do you 'splash' the EM vacuum into boson or fermion droplets? Metaphors only go so far.
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#2702 by graybeardsyseng on 24 May, 2016 07:43
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Concur - the max allowable input for the miniVNA -Tiny is 10mw RF - beyond that it is *Warranty Busting Time**. 10mW is not very much when coupling and feeding 100's of watts of RF from the Maggie and bouncing around in the DUT (Great build BTW). It would be very easy to have extra or unplanned coupling occurring which is overloading the VNA.First VNA results from my old TE311 frustum. Not very good, and physical tuning just seemed to make it worse. Physical tuning did nothing to the RL peak frequency, though it did have other effects at different frequencies not shown here. It also looks like I have two modes very near one another. I could remove the tuning section and solder on the small end-plate to see if that improves things, but I think it's best to move on to a new frustum.
I believe what you are seeing here is an artifact of the VNA, not a true representation of return loss. The VNA you are using is a digitized zero-IF receiver, and you're probably seeing aliasing from extreme over-drive of the front end of the receiver.
Do you have the capability to try inserting RF attenuators into the sense chain for the VNA? With an appropriate step attenuator it should be possible to quickly determine what effect the (notional) front end overload is having on the indicated RL. Just an additional note - if using surplus RF Step Attenuators from someplace like Ebay - be very to check all specs.
Herman
graybeardsyseng;
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#2703 by spupeng7 on 24 May, 2016 07:44
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Thinking about the metaphor, the wave-tank is the vacuum. The droplets represent bosons and fermions. But how do you 'splash' the EM vacuum into boson or fermion droplets? Metaphors only go so far.
Mwvp,
the graphic metaphors (such as the distended rubber sheet with various weights of ball moving around on it without any hysteresis) which are used to describe relativity, are misleading at best. Metaphors used in an attempt to elucidate QM are likely to be unhelpful.
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#2704 by RERT on 24 May, 2016 10:54
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Quote from: Star One
...some new but also old thinking on the behaviour of particles in this particular case photons.....
My Director of Studies in Maths said that he chose his thesis on "Elastodynamics of Self-gravitating Rigid Bodies under General Relativity" (IMHO gruesomely complex) in part to avoid the conceptual minefield which was quantum theory... -
#2705 by Star One on 24 May, 2016 12:28
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Quote from: Star One
...some new but also old thinking on the behaviour of particles in this particular case photons.....
My Director of Studies in Maths said that he chose his thesis on "Elastodynamics of Self-gravitating Rigid Bodies under General Relativity" (IMHO gruesomely complex) in part to avoid the conceptual minefield which was quantum theory...
From a lay person's viewpoint it often looks like we know less about the quantum realm than we think we do. As that article points out some of the processes underlying the universe look like they operate at faster than light speed.... -
#2706 by SeeShells on 24 May, 2016 16:01
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Quote from: Star One
...some new but also old thinking on the behaviour of particles in this particular case photons.....
My Director of Studies in Maths said that he chose his thesis on "Elastodynamics of Self-gravitating Rigid Bodies under General Relativity" (IMHO gruesomely complex) in part to avoid the conceptual minefield which was quantum theory...
From a lay person's viewpoint it often looks like we know less about the quantum realm than we think we do. As that article points out some of the processes underlying the universe look like they operate at faster than light speed....
I saw this video last year and was intrigued by it. First thing was I had to think of not a 2D surface effecting the particle, but look at it in 3D then it starts to make more sense.
I don't believe particles can in our universe's bound set of rules can travel faster than light speed, or or in truth faster than the speed of causality. To do so would violate entropy (something that's not talked about too much). The key is a exchange in energy or data. One thing that does violate actions is position and spin, for those can take place at a FTL speed.
If we entangle two photons so they are a mirror image, move them a kilometer apart and observe one the other photon switches state instantaneously. No data exchange, no energy exchange, no violation of entropy, just the spin of the photon changes FTL. For the current laws as we know them that violates nothing even causality.
This got me daydreaming last year if we did entangle the photons in the chamber between the modes and added something at one end that would mess with the spin force it in one direction, like a material that exhibited Chirality.
A photon gas in a resonate asymmetrical chamber with interlocking modes should exhibit http://imgur.com/a/iQzT3 photon entanglement between the modes.
In the semi chip industry this has been known for years.
Excerpt from wiki.
https://en.wikipedia.org/wiki/Photon_entanglement
An important area where entanglement can be applied is in computer microchips. Normally, the size of a microchip is restricted by the wavelength of the photon carving the chip, being able to carve at one-half of the wavelength in accordance with the Rayleigh criterion. However, entangled photons can be separated and then rejoined together, and since they have exactly the same position the constructive interference doubles the energy so that it can carve as low as 1/4 of the original wavelength and thus make microelectronic devices half the size of what was previously possible. Entangling more than one photon can lead to even greater energies, hitting 1/6 and theoretically even 1/8 the original wavelength.
Instantaneous communication by means of quantum entanglement is actually impossible because neither side can manipulate the state of the entangled particles, they can only measure it (see No-communication theorem). This fact means that if you measure one particle you cannot infer anything meaningful about the observers measuring the other particle, except you know what state they will measure, or have already measured. Thus causality is preserved.
So what do I build to test this idea? Something like EagleWorks dielectric insert?
http://imgur.com/e6OovSW I thought that was close.
I do a standard frustum (or slightly different) and make one change in adding a tuning chamber on top that will hold a extruded 1/2" piece of PTFE.
And to @monomorphic, this chamber is not quite for the tuning of a resonate mode but to tune a attached piece of PTFE through the cutoff area in the small end of the frustum to look for a peak value of thrust. A sweet spot. I want to capture those entangled photons and stop the normal Chirality direction of spin with the entangled actions of the photons and then decay them into a evanescent collapsing wave.
In a simplistic explanation I want to force them to spin in another direction against the Chirality characteristics of the PTFE with a spooky entangled action and since this does happen instantaneously with the entanglement actions of the photon in the large end we're not violating causality with exchange of data, just extraordinary spin (which we can do)... and momentum decaying into a collapsing evanescent wave into the small end. This all happens within the frustum closed frame and nothing gets violated.
Morning Hot Tub Thoughts for one of these upcoming tests.
My Best,
Shell
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#2707 by zellerium on 24 May, 2016 16:18
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First VNA results from my old TE311 frustum. Not very good, and physical tuning just seemed to make it worse. Physical tuning did nothing to the RL peak frequency, though it did have other effects at different frequencies not shown here. It also looks like I have two modes very near one another. I could remove the tuning section and solder on the small end-plate to see if that improves things, but I think it's best to move on to a new frustum.
It looks like its pretty close to what you're looking for, right?
Have you considered trying a tuning stub?
I noticed tuning 'trends' when I was trying to use a tuning stub in EM Pro. I would introduce a conductive perturbation, check the results and iterate until I found the trend I was looking for.
The lender of the magnetron antenna told us that when he was tuning waveguides he would sometimes put a nut inside and move it around until he found the RL he was looking for. When he found the location he would drill a screw into it from the outside to lock it in place. -
#2708 by X_RaY on 24 May, 2016 18:38
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Really interesting visualisation project of wave functions. Looks very nice especially at the end.
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#2709 by Monomorphic on 24 May, 2016 21:21
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And to @monomorphic, this chamber is not quite for the tuning of a resonate mode but to tune a attached piece of PTFE through the cutoff area in the small end of the frustum to look for a peak value of thrust.
I had the thought to use HDPE attached to the tuning end to slowly push it into the cavity. I need to lower the resonant frequency by about 10Mhz and I figure that's the best way to try. PTFE is expensive! A 4" diameter cylinder is $350/ft on McMaster-Carr. Compared to $32/ft for HDPE. -
#2710 by Monomorphic on 24 May, 2016 21:50
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Speaking of dialectrics, I noticed Cannnae has updated some of the language on their website. This new piece stuck out the most:
"Cannae is also commercializing a thruster that does not require superconducting operation in order to generate thrust. This thruster also requires no on-board propellant. It uses dielectric materials within a resonant electromagnetic structure in order to generate thrust. Cannae has also developed and demonstrated this technology at our Pennsylvania test facility."
This language is new, as I posted about their claiming no dialectrics were required shortly after their new site went live. Before it only claimed the following:
"The core of our technology uses electromagnetic, radio-frequency resonant thrusters with unique geometries creating Lorentz Force imbalances to generate thrust. Cannae has demonstrated 2 separate prototypes of a superconducting thruster which requires no dielectric material to generate thrust." -
#2711 by SeeShells on 24 May, 2016 22:00
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Speaking of dialectrics, I noticed Cannnae has updated some of the language on their website. This new piece stuck out the most:
Ever wonder what the plug was in the end of the cavity that the antenna ran through? hmmm.
"Cannae is also commercializing a thruster that does not require superconducting operation in order to generate thrust. This thruster also requires no on-board propellant. It uses dielectric materials within a resonant electromagnetic structure in order to generate thrust. Cannae has also developed and demonstrated this technology at our Pennsylvania test facility."
This language is new, as I posted about their claiming no dialectrics were required shortly after their new site went live. Before it only claimed the following:
"The core of our technology uses electromagnetic, radio-frequency resonant thrusters with unique geometries creating Lorentz Force imbalances to generate thrust. Cannae has demonstrated 2 separate prototypes of a superconducting thruster which requires no dielectric material to generate thrust."
Shell -
#2712 by Monomorphic on 24 May, 2016 22:26
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Maybe it's reading too much between the lines, but the plural use of "dialectric materials" could mean layers of dialetrics with different properties. Like the sim I ran here. Left is no dialectric, right is layers of dialectrics with a gradient of different properties.
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#2713 by SeeShells on 24 May, 2016 23:28
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Maybe it's reading too much between the lines, but the plural use of "dialectric materials" could mean layers of dialetrics with different properties. Like the sim I ran here. Left is no dialectric, right is layers of dialectrics with a gradient of different properties.
You need a copper disk on the top of the dielectric.
Shell
BTW http://www.ebay.com/itm/PTFE-TEFLON-ROD-WHITE-4-DIAMETER-1-3-4-LONG-ROD-DISC-/231808871927?hash=item35f8e2adf7:g:Y0EAAOSwX~dWkW3X -
#2714 by apoc2021 on 25 May, 2016 00:41
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I sometimes wonder whether the emdrive experiments are in some way actually experiments with gravity or expansion. What if rather than observing the article move, we are actually observing the article stand still while we move? I would then guess it would be important to consider the role that time plays.
Forgive the rambling - not sure why I was compelled to share that errant thought - but I do sometimes enjoy turning questions upside down while searching for new perspective. -
#2715 by dustinthewind on 25 May, 2016 01:16
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...
Thinking about the metaphor, the wave-tank is the vacuum. The droplets represent bosons and fermions. But how do you 'splash' the EM vacuum into boson or fermion droplets? Metaphors only go so far.
Some more on the hidden variables debate in quantum mechanics.
http://plato.stanford.edu/entries/qm-bohm/Quote"Bohmian mechanics, which is also called the de Broglie-Bohm theory, the pilot-wave model, and the causal interpretation of quantum mechanics, is a version of quantum theory discovered by Louis de Broglie in 1927 and rediscovered by David Bohm in 1952. It is the simplest example of what is often called a hidden variables interpretation of quantum mechanics.
...
2. The Impossibility of Hidden Variables … or the Inevitability of Nonlocality?
John von Neumann, one of the greatest mathematicians of the twentieth century, claimed that he had proven that Einstein's dream of a deterministic completion or reinterpretation of quantum theory was mathematically impossible. ...
Physicists and philosophers of science almost universally accepted von Neumann's claim. ...
The identity of C is, however, of great historical significance: it is responsible for the misconception that Bell proved that hidden variables are impossible, a belief that physicists until recently almost universally shared, as well as for the view, even now almost universally held, that what Bell's result does is to rule out local hidden variables, a view that is misleading."
"Bohmian mechanics does not account for phenomena such as particle creation and annihilation characteristic of quantum field theory. This is not an objection to Bohmian mechanics but merely a recognition that quantum field theory explains a great deal more than does nonrelativistic quantum mechanics, whether in orthodox or Bohmian form. It does, however, underline the need to find an adequate, if not compelling, Bohmian version of quantum field theory, and of gauge theories in particular.
...
“Bell-type quantum field theories” (Dürr et al., 2004 and 2005) describe a stochastic evolution of particles that involves particle creation and annihilation. (For a general discussion of this issue, and of the point and value of Bohmian mechanics, see the exchange of letters between Goldstein and Weinberg by following the link provided in the Other Internet Resources section below.)"
I am not sure how developed the theory is to be honest but I like that they are trying to understand what the underlying structure of what QM may be. -
#2716 by dustinthewind on 25 May, 2016 02:03
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Dr. Rodal, at the end of the Ames talk Sonny describes moving forward and mentions "phase lock loop", forgive my high school physics only, but would phase lock looping eliminate or mitigate the issues associated with modes being too "close" to one another? Not to mention your above mentioned antenna looping and positioning advice. Your help is greatly appreciated. FL (below attached image of "moving forward" frustum)
The problem is the phase lock loop circuit is being fooled by the modes being too close together. The circuit assumes that the frustum has only one mode and tries to maximise the output. Where the modes are far apart the only one mode approximation works. Where two or more modes are close the circuit sometimes detects the other mode and tries locking on to it. This happens repeatedly. Consequently the loop drives like a drunk and the equipment ends up in neither mode.
I wonder if that would call for a filter circuit to fine tune which frequency it locks onto. Or amplifies a very narrow bandwidth at a specific frequency. -
#2717 by meberbs on 25 May, 2016 02:53
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I am not sure how developed the theory is to be honest but I like that they are trying to understand what the underlying structure of what QM may be.
The author of that page spends way to much effort tearing down stawnmen before explaining the theory.QuotePhysicists and philosophers of science almost universally accepted von Neumann's claim.
Not any modern ones that I know of. This statement is somewhat taken back later:QuoteRecently, however, physicists more commonly cite the Kochen-Specker Theorem and, more frequently, Bell's inequality in support of the contention that a deterministic completion of quantum theory is impossible.
As a relatively recent student of quantum mechanics, the only theory related to determinism that I learned was Bell's inequality and with the clear caveat that it only disproves local hidden variable theory, not non-local.
Citing 40 year old inaccurate statements to claim that there is any modern controversy seems pointless.
I didn't read the rest in detail, the theory is probably fine since it claims to obey quantum dynamics and be a non-local theory. Physicists mostly ignore this kind of theory because non-locality is even harder to understand than non-determinism, and from what I skimmed, I saw no claims that this produces any testable predictions that differ from the more common interpretations of quantum mechanics.
I noticed this in the response to criticism section:QuoteMore recently, Sir Anthony Leggett has echoed this charge. Referring to the measurement problem, he says (Leggett 2005) that Bohmian mechanics provides “little more than verbal window dressing of the basic paradox.”
The fact that there was essentially no math in the entire paper seems to support this statement.
The response given (below) is unsubstantiated, and I don't see how a non-local hidden variable theory can be considered "clear" when you consider the implications of non-local and special relativity.QuoteSupporters of Bohmian mechanics give more weight to its greater simplicity and clarity.
This may be a useful way for thinking about quantum mechanics, but I'll have to look it up from some other source, since this author seems to think they have the only correct interpretation of quantum, and keeps trying to paint anyone who supports the more common interpretation as absurd, despite no experimental difference being presented. -
#2718 by spupeng7 on 25 May, 2016 07:15
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X-ray or whom-ever might know,
what happens between the filament and the anode in the diagram above. Is it an arc or is it more ordered than that, some sort of plasma. I ask because it seems logical that it should transmit all the output power of the maggie. I understand that the frequency is generated by the epicycles that the electrons move in (corralled by the magnetic field between the permanent magnets) until they are grounded, the difficulty I am having is understanding how all this can happen without loss of the vacuum or melting of the filament. -
#2719 by spupeng7 on 25 May, 2016 07:26
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Zellerium, a BB might be easier to move around in there.First VNA results from my old TE311 frustum. Not very good, and physical tuning just seemed to make it worse. Physical tuning did nothing to the RL peak frequency, though it did have other effects at different frequencies not shown here. It also looks like I have two modes very near one another. I could remove the tuning section and solder on the small end-plate to see if that improves things, but I think it's best to move on to a new frustum.
It looks like its pretty close to what you're looking for, right?
Have you considered trying a tuning stub?
I noticed tuning 'trends' when I was trying to use a tuning stub in EM Pro. I would introduce a conductive perturbation, check the results and iterate until I found the trend I was looking for.
The lender of the magnetron antenna told us that when he was tuning waveguides he would sometimes put a nut inside and move it around until he found the RL he was looking for. When he found the location he would drill a screw into it from the outside to lock it in place.
