Quote from: TheTraveller on 10/04/2017 10:32 pmQuote from: tchernik on 10/04/2017 08:02 pmHence the comments about such stringent geometry and polishing requirements being an example of 'raising the goalpost' for experimentalists.Followed by "If you don't have it, you won't see it. Told you so".Not very auspicious.I really hope the ongoing experiments prove otherwise.As I suggested before, please share with the real world accelerator cavity and waveguide makers they can stop polishing their interior surfaces and using electro polishing to eliminate scratches, plus they can throw away all their very tight manufacturing tolerances.Maybe look into a space rated waveguide and explore the manufacturing tolerances, then talk to people that make accelerator cavities?I agree I'm no expert.Personally, I'm more interested in the experiments trying to conclusively prove that 1) these things actually exist and 2) work in a vacuum as thrusters with greater efficiency than a perfectly collimated photon rocket.Due to lack of proof on the matter, super-strong Emdrives that can levitate cars for me simply don't exist. If some clear evidence emerges tomorrow, I'd change my mind, but there is none so far.With those interests in mind, I think a passably good cavity that could be made by a DIY builder or an engineer with regular materials and machinery, and without impossible space-industry quality requirements, could be used to prove those points.Roger Shawyer himself started there, as far as I know. His first Emdrives weren't that much different from what several DIY engineers are doing now. And none of his designs have been tested in a vacuum chamber, also as far as I know. Thus NASA EW's and now Prof. Tajmar's experiments will have a clear advantage towards those 2 goals I mentioned.
Quote from: tchernik on 10/04/2017 08:02 pmHence the comments about such stringent geometry and polishing requirements being an example of 'raising the goalpost' for experimentalists.Followed by "If you don't have it, you won't see it. Told you so".Not very auspicious.I really hope the ongoing experiments prove otherwise.As I suggested before, please share with the real world accelerator cavity and waveguide makers they can stop polishing their interior surfaces and using electro polishing to eliminate scratches, plus they can throw away all their very tight manufacturing tolerances.Maybe look into a space rated waveguide and explore the manufacturing tolerances, then talk to people that make accelerator cavities?
Hence the comments about such stringent geometry and polishing requirements being an example of 'raising the goalpost' for experimentalists.Followed by "If you don't have it, you won't see it. Told you so".Not very auspicious.I really hope the ongoing experiments prove otherwise.
...Can you imagine how small the difference is regarding the volume to surface ratio due to a few µm deep scratch for such a cavity resonator, at 2...4 GHz? Sure the wall currents are slightly bent at the scratch but in contrast to the local wavelength this is so damn tiny that it almost don't matter because the conductivity in the region dont change.What impacts the Q factor is the conductivity of the walls and maybe inhomogeneities of the order of lets say 1/10 of the wavelength or something like that. Monomorphic has shown some calculations to this subject a few threads ago. Dr. Rodal showed an analytic calculation of the Q factor as well as others. I would be happy if you show us a Q comparison (i.e. calculations or even measurements!) of a cavity with the high surface quality you state, with the same one after a few scratches were made.http://forum.nasaspaceflight.com/index.php?topic=39214.msg1474347#msg1474347http://www.gregegan.net/SCIENCE/Cavity/Cavity.htmlhttp://forum.nasaspaceflight.com/index.php?topic=39772.msg1503747#msg1503747http://forum.nasaspaceflight.com/index.php?topic=39772.msg1503825#msg1503825http://forum.nasaspaceflight.com/index.php?topic=39772.msg1504635#msg1504635I bet even with the best VNA you can get (within its uncertainty range) you will see no difference even using high average values. If you think you can reject this please deliver real results!
Quote from: TheTraveller on 10/04/2017 10:32 pmQuote from: tchernik on 10/04/2017 08:02 pmHence the comments about such stringent geometry and polishing requirements being an example of 'raising the goalpost' for experimentalists.Followed by "If you don't have it, you won't see it. Told you so".Not very auspicious.I really hope the ongoing experiments prove otherwise.As I suggested before, please share with the real world accelerator cavity and waveguide makers they can stop polishing their interior surfaces and using electro polishing to eliminate scratches, plus they can throw away all their very tight manufacturing tolerances.Maybe look into a space rated waveguide and explore the manufacturing tolerances, then talk to people that make accelerator cavities?I agree I'm no expert....Roger Shawyer himself started there, as far as I know. His first Emdrives weren't that much different from what several DIY engineers are doing now. And none of his designs have been tested in a vacuum chamber, also as far as I know. Thus NASA EW's and now Prof. Tajmar's experiments will have a clear advantage towards those 2 goals I mentioned.
Temperature sensor inside the draft enclosure is working. I ended up going with a 4-20mA signal with pt100 resistance temperature sensor. Here is a screen cap of all 5 channels of data I will be collecting off the torsional pendulum. I can still add up to three more channels. Every once in a while I notice a fairly strong repetitive RF signal in this band. I'm not sure what it is except perhaps my neighbor's microwave oven. Does anyone recognize the signal in channel 4?
Quote from: Rodal on 10/02/2017 06:51 pmNothing (whether anisotropic, inhomogeneous, etc.) that one can do solely with internal fields, internal forces, or internal particles can result in acceleration of the center of mass by itself without the involvement of external fields, as this would be a violation of Noether's theorem. Acceleration of the center of mass can only take place either by ejection of mass/energy or by involvement of an external field.So if there's an external field involved here, what is it? (And please don't tell me it's a "field of dreams" )Is it the Quantum Foam (aka. Dynamic Vacuum) ?
Nothing (whether anisotropic, inhomogeneous, etc.) that one can do solely with internal fields, internal forces, or internal particles can result in acceleration of the center of mass by itself without the involvement of external fields, as this would be a violation of Noether's theorem. Acceleration of the center of mass can only take place either by ejection of mass/energy or by involvement of an external field.
sanman,gravity and inertia are inextricably linked by the principle of equivalence and by their common dependence upon the depth of the gravitational field within which their mechanism acts. By this I mean that gravitational and inertial mass are phenomena whose weight varies with depth into the gravitational field.
Quote from: sanman on 10/03/2017 06:23 amSo if there's an external field involved here, what is it? (And please don't tell me it's a "field of dreams" )Is it the Quantum Foam (aka. Dynamic Vacuum) ?sanman,gravity and inertia are inextricably linked by the principle of equivalence and by their common dependence upon the depth of the gravitational field within which their mechanism acts. By this I mean that gravitational and inertial mass are phenomena whose weight varies with depth into the gravitational field.This then is sure, that they both depend upon an external meter for their action. That being so they cannot be local phenomena because they depend upon external conditions. How then are they not Machian by nature?
So if there's an external field involved here, what is it? (And please don't tell me it's a "field of dreams" )Is it the Quantum Foam (aka. Dynamic Vacuum) ?
We know that mass is composed of charges so it is beyond doubt that gravity and inertia act upon charges, which is to me at least, a strong argument that their mechanisms must be electrical. Why should they not be the external field we are looking for?
Surface resistance as function of roughnessI have found an article in which the degradation of Q as function of the surface roughness is studied: Hernandez et al, 1986 (attached). They don't list the measured Q's, but the derived surface resistance (measured at ~11 GHz). I quote: "The variation in the normalised surface resistance against roughness has the same form in all the figures. The surface resistance increases quickly with roughness in the interval 0<r/∂<1, and reaches asymptotically a maximum value that depends on the metal for r/∂ >2." (r/∂ being the groove depth relative to the skin depth).For copper, the surface resistance increases to a maximum of ~35% with grooves of several times the skin depth. If you don't mind a Q degradation of a factor of two, this is not something to worry about too much, it seems.Even more interesting in this article: they treat suppression of TM modes:"We have found empirically that the most effective way to reduce the TM112 effect is the combination of two different techniques: allowing a gap between the cylindrical wall and one of the end plates (Atia and Williams 1976) and the production of the cavity excitation by means of a rectangular iris, parallel to the axis of the cavity, in the side wall (Aron 1967)."I don't have the article by Aron yet, my univ does not have a subscription.[you can buy it on http://digital-library.theiet.org/content/journals/10.1049/piee.1967.0197 ]The use of the gap is obvious, of course, if you measure at TE-modes (but I made my cavity with the desire to also measure at TM-modes. I can isolate the small endplate in case of TE-mode, though it will radiate then (enough shielding when wrapping in Al-foil?)).
...Plus yes once the grove depth is several times the skin depth, going deeper has no effect as the skin current does not go that deep. Max current depth is 5x skin depth.
Quote from: TheTraveller on 10/05/2017 12:31 pm...Plus yes once the grove depth is several times the skin depth, going deeper has no effect as the skin current does not go that deep. Max current depth is 5x skin depth.But the main conclusion from the Hernandez et al., 1986 study is that the increased surface roughness only increases the surface resistance by some tens of percent.
For copper, the surface resistance increases to a maximum of ~35% with grooves of several times the skin depth. If you don't mind a Q degradation of a factor of two, this is not something to worry about too much, it seems.
Q dropped 100x.
could not make out your time stamp but the signal looks similar to a cell phone presence signal which would also be intermittant.
....But since the mechanism of EMdrive is photons, which are carriers of electromagnetic force (including charge force), then I'll agree that whatever the EMdrive's traveling wave is acting on, would likewise have to be characterized by electrical charge forces. And that would be the various fleeting fluctuations of the Dynamic Vacuum / Quantum Foam.
…Mach effect Imho - A particle exists in the vacuum by occupying a place that nothing else can. As such, it constitutes a single boundary for all vacuum wave functions around it. As a boundary, it receives continual momentum from all directions making the particle jiggle around, a sort of vacuum Brownian motion. This is why its position and momentum are not intrinsically definite, since its existence is inseparable from the vacuum and its fluctuations. When we accelerate the particle, the boundary function becomes asymmetric creating the force exposed by Casimir. It seems to indicate that inertia, or the resistance to acceleration, is the Casimir force resulting from an asymmetric contact with the effect of the vacuum. This means that we accelerate with respect to the vacuum. The Mach effect says that we accelerate with respect to the rest of the universe. It is true in a large sense, but in practice, it is more local. The local condition of the vacuum is in effect part of “the rest of the universe”, as not being at the same place, as already taken by the particle.Now go and have a good night sleep
Quote from: sanman on 10/05/2017 04:39 am....But since the mechanism of EMdrive is photons, which are carriers of electromagnetic force (including charge force), then I'll agree that whatever the EMdrive's traveling wave is acting on, would likewise have to be characterized by electrical charge forces. And that would be the various fleeting fluctuations of the Dynamic Vacuum / Quantum Foam.Though at present it does not appear useable, the Casimir effect seem to demonstrate that momentum can be transferred between the QV and matter.
Quote from: OnlyMe on 10/05/2017 05:51 pmQuote from: sanman on 10/05/2017 04:39 am....But since the mechanism of EMdrive is photons, which are carriers of electromagnetic force (including charge force), then I'll agree that whatever the EMdrive's traveling wave is acting on, would likewise have to be characterized by electrical charge forces. And that would be the various fleeting fluctuations of the Dynamic Vacuum / Quantum Foam.Though at present it does not appear useable, the Casimir effect seem to demonstrate that momentum can be transferred between the QV and matter.Regarding Casimir, QV, Scratches, Wall potential, time and experimental design for QV related gain: You are correct. The Casimir effect is irrelevant here unless you squeeze the vacuum significantly with an inhomogeneous anistropic medium. In such compressed states of spacetime you are essentially forcing more of the QV into less spacetime therefore increasing the Casimir force by a finite amount. It is curious to consider possible warping (yes stiffness is mitigated if the field is oscillatory and relatively low density) in the context of the cavity. This idea is far from novel however. ...
Quote from: sanman on 10/05/2017 04:39 am....But since the mechanism of EMdrive is photons, which are carriers of electromagnetic force (including charge force), then I'll agree that whatever the EMdrive's traveling wave is acting on, would likewise have to be characterized by electrical charge forces. And that would be the various fleeting fluctuations of the Dynamic Vacuum / Quantum Foam.First, photons are not charged particles, even massless charged particles, thus while their interaction with charged particles (matter) often results in changes in electromagnetic (EM) potentials, the photon itself may not be a carrier of EM energy. Even while it is a carrier of energy that may upon interaction with matter be expressed as an EM potential.
Quote from: M.LeBel on 10/04/2017 12:16 am…Mach effect Imho - A particle exists in the vacuum by occupying a place that nothing else can. As such, it constitutes a single boundary for all vacuum wave functions around it. As a boundary, it receives continual momentum from all directions making the particle jiggle around, a sort of vacuum Brownian motion. This is why its position and momentum are not intrinsically definite, since its existence is inseparable from the vacuum and its fluctuations. When we accelerate the particle, the boundary function becomes asymmetric creating the force exposed by Casimir. It seems to indicate that inertia, or the resistance to acceleration, is the Casimir force resulting from an asymmetric contact with the effect of the vacuum. This means that we accelerate with respect to the vacuum. The Mach effect says that we accelerate with respect to the rest of the universe. It is true in a large sense, but in practice, it is more local. The local condition of the vacuum is in effect part of “the rest of the universe”, as not being at the same place, as already taken by the particle.Now go and have a good night sleepThere seems some similarity above to the early Haisch, Rueda and Puthoff Inertia model.1998 Inertia as reaction of the vacuum to accelerated motionRueda & Haischhttps://arxiv.org/abs/physics/9802031v11998 Advances in the Proposed Electromagnetic Zero-Point Field Theory of InertiaHaisch, Rueda, Puthoffhttps://arxiv.org/abs/physics/9807023v2
Quote from: OnlyMe on 10/05/2017 05:51 pmQuote from: sanman on 10/05/2017 04:39 am....But since the mechanism of EMdrive is photons, which are carriers of electromagnetic force (including charge force), then I'll agree that whatever the EMdrive's traveling wave is acting on, would likewise have to be characterized by electrical charge forces. And that would be the various fleeting fluctuations of the Dynamic Vacuum / Quantum Foam.First, photons are not charged particles, even massless charged particles, thus while their interaction with charged particles (matter) often results in changes in electromagnetic (EM) potentials, the photon itself may not be a carrier of EM energy. Even while it is a carrier of energy that may upon interaction with matter be expressed as an EM potential.Hi, I know that - I only meant that photons are said to be mediators between charge interactions.Quote from: OnlyMe on 10/05/2017 06:16 pmQuote from: M.LeBel on 10/04/2017 12:16 am…Mach effect Imho - A particle exists in the vacuum by occupying a place that nothing else can. As such, it constitutes a single boundary for all vacuum wave functions around it. As a boundary, it receives continual momentum from all directions making the particle jiggle around, a sort of vacuum Brownian motion. This is why its position and momentum are not intrinsically definite, since its existence is inseparable from the vacuum and its fluctuations. When we accelerate the particle, the boundary function becomes asymmetric creating the force exposed by Casimir. It seems to indicate that inertia, or the resistance to acceleration, is the Casimir force resulting from an asymmetric contact with the effect of the vacuum. This means that we accelerate with respect to the vacuum. The Mach effect says that we accelerate with respect to the rest of the universe. It is true in a large sense, but in practice, it is more local. The local condition of the vacuum is in effect part of “the rest of the universe”, as not being at the same place, as already taken by the particle.Now go and have a good night sleepThere seems some similarity above to the early Haisch, Rueda and Puthoff Inertia model.1998 Inertia as reaction of the vacuum to accelerated motionRueda & Haischhttps://arxiv.org/abs/physics/9802031v11998 Advances in the Proposed Electromagnetic Zero-Point Field Theory of InertiaHaisch, Rueda, Puthoffhttps://arxiv.org/abs/physics/9807023v2I remember reading that stuff when it first came out, and I recall it was heavily attacked - particularly over ideas like "Rindler frames". They were claiming an electromagnetic origin for gravity and inertia.