Actually, I forgot that Tajmar had a screw-driven reduction in length. The length given must be the external length, the maximum length possible.The COMSOL FEA image from Tajmar shows an internal length which is SMALLER than the big diameter. If I use this aspect ratio, and doubling the diameters I can get a natural frequency for TE111 around 2.45 GHzSo, yes it makes sense that:The diameters given are actually the radii. The diameters are twice as big as given

Quote from: Rodal on 07/26/2015 11:58 PMActually, I forgot that Tajmar had a screw-driven reduction in length. The length given must be the external length, the maximum length possible.The COMSOL FEA image from Tajmar shows an internal length which is SMALLER than the big diameter. If I use this aspect ratio, and doubling the diameters I can get a natural frequency for TE111 around 2.45 GHzSo, yes it makes sense that:The diameters given are actually the radii. The diameters are twice as big as givenGood. So we agree and our modelling software agree.Would be nice to know the internal dimensions but I suspect what we have is what we will get. I did take 2mm off the diameters (assumed 1mm thick side walls) as I believe they are probably external dimensions, like the length is the overall external dimension.At least we how have resonance and mode numbers that make sense.

@Dr. RodalThe new big and small end lateral antenna csv files are up and I have removed the previous version. This time they are in two folders so you won't get them mixed up. Naming convention is the same as my most recent previous data set uploaded, with only the base name changed, as you will see.Each folder contains a Meep Data Request file to describe the run. Ask me for the information that I forgot to add.https://drive.google.com/folderview?id=0B1XizxEfB23tfkF0Z184NHRtd0ViN28tNzRDY3JzSVc0WFBTOGZmSFZMcUpWLWJfcDRfZEU&usp=sharingaero

Thinking helps me to take a pause.I have a silly question that I'm trying to wrap my head around it and need some help.The group velocity holds the energy, momentum and information in a waveguide but the phase velocity can be superluminal in a waveguide. I see this.But...When the waves carrying energy, momentum and information reach cutoff and collapse in a wave guide then the superluminal phase velocity also collapses and in that instant where the phase velocities are collapsing from a superluminal speed into the group velocity wave front. What happens? Make sense?Shell

video link in this post.

And thanks and warm congratulations to X-Ray for first thinking about the factor of 2:http://forum.nasaspaceflight.com/index.php?topic=37642.msg1409910#msg1409910

Quote from: birchoffWhats the predicted thrust if you drop the 700W to 360W using the initial Q of 48.8? Also what do the numbers look like if you assume the model that was used was the one in equation 1 of The Development of a Microwave Engine for Spacecraft Propulsion66uN is the Force prediction at a Q of 48.8.Equation 1 in the 2005 Brighton paper is obsolete. My spreadsheet uses the Force equation in the current theory paper as attached.

Whats the predicted thrust if you drop the 700W to 360W using the initial Q of 48.8? Also what do the numbers look like if you assume the model that was used was the one in equation 1 of The Development of a Microwave Engine for Spacecraft Propulsion

Quote from: TheTraveller on 07/26/2015 11:51 PMQuote from: birchoffWhats the predicted thrust if you drop the 700W to 360W using the initial Q of 48.8? Also what do the numbers look like if you assume the model that was used was the one in equation 1 of The Development of a Microwave Engine for Spacecraft Propulsion66uN is the Force prediction at a Q of 48.8.Equation 1 in the 2005 Brighton paper is obsolete. My spreadsheet uses the Force equation in the current theory paper as attached.I understand that the model in the paper I referenced is superseded. However I am assuming that since Tajmar didnt reference that paper you attached that the model used is the one from the paper I am referencing.

polarized slot antenna, poor rl, surprised at any results...which is a good thing for the ongoing project.

Quote from: rfmwguy on 07/27/2015 01:10 AMpolarized slot antenna, poor rl, surprised at any results...which is a good thing for the ongoing project.All I can add is that Tajmar is not an Rf microwave engineer.Suspect he called in Shawyer when he got no results.Even with Shawyers help his magnetron runs at 200C, while the small end of the cavity runs at 35C. This suggests to me the reflected power is way higher than 336W and that the real power inside the cavity is much lower than 360Ws.This again says us EMDrive DIYers need to be able to measure our VSWR or return loss dBs and to do adjustments to get them as optimal as possible so to at least have a fighting chance to see some Force generated.

Quote from: birchoff on 07/27/2015 01:08 AMQuote from: TheTraveller on 07/26/2015 11:51 PMQuote from: birchoffWhats the predicted thrust if you drop the 700W to 360W using the initial Q of 48.8? Also what do the numbers look like if you assume the model that was used was the one in equation 1 of The Development of a Microwave Engine for Spacecraft Propulsion66uN is the Force prediction at a Q of 48.8.Equation 1 in the 2005 Brighton paper is obsolete. My spreadsheet uses the Force equation in the current theory paper as attached.I understand that the model in the paper I referenced is superseded. However I am assuming that since Tajmar didnt reference that paper you attached that the model used is the one from the paper I am referencing.Equation 11 in the 2010 paper (referenced by Tajmar) is the current Force equation, which also details how to calc the Df.

Quote from: TheTraveller on 07/27/2015 01:47 AMQuote from: rfmwguy on 07/27/2015 01:10 AMpolarized slot antenna, poor rl, surprised at any results...which is a good thing for the ongoing project.All I can add is that Tajmar is not an Rf microwave engineer.Suspect he called in Shawyer when he got no results.Even with Shawyers help his magnetron runs at 200C, while the small end of the cavity runs at 35C. This suggests to me the reflected power is way higher than 336W and that the real power inside the cavity is much lower than 360Ws.This again says us EMDrive DIYers need to be able to measure our VSWR or return loss dBs and to do adjustments to get them as optimal as possible so to at least have a fighting chance to see some Force generated.In the acknowledgements, Tajmar et.al. thanks <<Prof. Plettemeier from TU Dresden who assisted our Q factor measurements.>>Presumably, they have people at The Technische Universität Dresden that know about Electrical Engineering and Microwave cavities, and it looks like Prof. Plettemeier may be one of themProf. Dr.-Ing. Dirk PlettemeierHead and Chair of the Department of RF and Photonics in the department of Electrical EngineeringMicrowavesTel .: +49 351463-33941http://tu-dresden.de/die_tu_dresden/fakultaeten/fakultaet_elektrotechnik_und_informationstechnik/ifn/hf/organisationhttp://tu-dresden.de/die_tu_dresden/fakultaeten/fakultaet_elektrotechnik_und_informationstechnik/ifn/hf/forschung/hochfrequenzsystemehttp://tu-dresden.de/die_tu_dresden/fakultaeten/fakultaet_elektrotechnik_und_informationstechnik/ifn/hf/forschung/mikrowellenphotonik/index_html/document_view?set_language=en

Quote from: aero on 07/25/2015 10:40 PM@Dr. RodalThe new big and small end lateral antenna csv files are up and I have removed the previous version. This time they are in two folders so you won't get them mixed up. Naming convention is the same as my most recent previous data set uploaded, with only the base name changed, as you will see.Each folder contains a Meep Data Request file to describe the run. Ask me for the information that I forgot to add.https://drive.google.com/folderview?id=0B1XizxEfB23tfkF0Z184NHRtd0ViN28tNzRDY3JzSVc0WFBTOGZmSFZMcUpWLWJfcDRfZEU&usp=sharingaeroI downloaded (after re-installing Google Drive, which was malfunctioning) the files for the case of the lateral antenna at the Small End of Yang/Shell, and I computed the stresses and forces.Before posting the data, would you be so kind as to verify whether you obtained the big base and the small base at the following locations?These are the locations where Mathematica shows the bases:BIG BASE : row 15 (rows ranging from 0 to 228)SMALL BASE : row 214 (rows ranging from 0 to 228)Please note:1) I adopted the same convention as yours: rows starting at zero2) when I plot the stress for the big base it looks very small, that's why I would like you to double-check whether the locations are correct******************Also, did you ever run csv files for rfmwguy lateral antenna at the Big Base? All I recall is the antenna at the small end.

...__________________________________No, I don't recall ever having run having moved the lateral antenna to the big end for rfmwguy's NSF-1701 model. It's to late to run it tonight but I could run it tomorrow if you like.

...Wish it were that simple, but folks it aint.

Quote from: flux_capacitor on 07/26/2015 05:27 PMQuote from: TheTraveller on 07/26/2015 04:09 PMThis short length, constant diameter, cylindrical step out ("retraction" size of the cover depth) design also seems to eliminate the need for spherical end plates, which would be a really big win.Yes but the Chinese used a noisy 1000W magnetron, which has AM and FM modulation over a wider bandwidth than your cleaner solid-state 100W RF amp. I remember Shawyer told you to use a magnetron with flat end plates, but a narrow-band emitter with spherical ends.Correct.But the new build Prof Yang has shared allows using flat end plates to obtain a Q of 117,500 by using short constant diameter set backs as attached. I assume the set backs convert a spherical wavefront into a planar wavefront in both directions.When using a tapered waveguide to connect different diameter cylindrical waveguides this is what happens. Planar going in, spherical inside the tapered section and planar when emerging into the opposite side constant diameter cylindrical section.I see this as a major advancement in EMDrive frustum design.My 1st build has now altered to be able to experiment with this new structure as attached. Double ended tuning with sliding end plates inside constant diameter sections. Shawyer did do this for the small end in his Demonstrator EMDrive and repeated it with the Tajmar EMDrive. Both magnetron driven.If this setup can eliminate the need for spherical end plates and still deliver an unloaded Q of 117,500, bring it on.BTW to those "group velocity is different at each end of the frustum" doubters, wonder what the group velocity will be in those constant diameter sections? Would suggest it will be the group velocity as per the constant diameter circular waveguide equations. Which means Cullen, Shawyer & Prof Yang are correct.

Quote from: TheTraveller on 07/26/2015 04:09 PMThis short length, constant diameter, cylindrical step out ("retraction" size of the cover depth) design also seems to eliminate the need for spherical end plates, which would be a really big win.Yes but the Chinese used a noisy 1000W magnetron, which has AM and FM modulation over a wider bandwidth than your cleaner solid-state 100W RF amp. I remember Shawyer told you to use a magnetron with flat end plates, but a narrow-band emitter with spherical ends.

This short length, constant diameter, cylindrical step out ("retraction" size of the cover depth) design also seems to eliminate the need for spherical end plates, which would be a really big win.

Quote from: TheTraveller on 07/27/2015 01:00 AM...Wish it were that simple, but folks it aint.I ran through the equations and can't seem to get the numbers from that calculator, would you kindly show me what I'm doing wrong?RL(dB) = 10*log10(Power incident/power reflected)if RL = 12.5 dB, Power incident = 700 W, then power reflected is 39.3 W, not 339.9 Wor RHO = 10^(-RL/20)VSWR = (1+abs(RHO))/(1-abs(RHO)) = 1.62MisMatch = 10*log10(1-RHO^2) = -0.251%P_reflected = 100*RHO^2 = 5.623which gives the same 39.3 W reflected. Thank youIn regards to Tajmar's paper, I am curious as to why his thrust signature dropped in correspondence with the magnetron temperature. I don't believe any other experimenters observed this...In a vacuum of 10^-6 Torr I would have a hard time believing it could be air currents. But I haven't run through the calcs yet.Also, the difference in negative and positive horizontal thrusts tells me there must be some interaction that hasn't been accounted for. Reminds me of the difference in forward and reverse from the Cannae test in Brady et al.Build update: we are almost finished manufacturing and aim to begin testing within a week or so on our symmetric partially loaded (with HDPE) cylindrical resonant cavity. Our laser measurement detector has been calibrated and can detect ~ 10 um in the morning (before people enter the building, AC turns on etc) but we haven't put it on the pendulum yet which I'm sure will add considerable noise. I'll update again when we have some results

Anybody know anything about SuperFish?http://www.lanl.gov/projects/feynman-center/technologies/software/poisson-superfish.php