Quote from: deltaMass on 07/12/2015 01:26 amJust to note that there have been dozens of experiments on The Woodward Effect which have returned a result compatible with the null hypothesis. This is not something that one normally hears about, though.Many nails in that coffin, sad to say.I would be interested in knowing of any nullification experiments for Woodward's hypothesis. The only one I had seen was the one by Brito Marini and Galian but a number of Mach Effect supporters came from other threads and posted that I should ignore it because that report dealt with what they call Mach Lorentz thruster (MLT) and not the Mach Effect thruster (MET) (or something to that effect MET dealing with piezoelectric effects instead of electromagnetic effects for MLT, of something like that, I don't recall the gory details). Any other nulllifiication reports, please
Just to note that there have been dozens of experiments on The Woodward Effect which have returned a result compatible with the null hypothesis. This is not something that one normally hears about, though.Many nails in that coffin, sad to say.
Quote from: Ricvil on 07/11/2015 02:08 amI'm just looking for a possible hybrid mode on cavity. But it is not so easy.There are some possibles candidates on Nasa's paper.Some formulas of sensitivity can be used for adjust the dimensions of cavity and to control the frequencys.Very cool.By the way. In corrugated waveguides, hybrid modes have very low losses. In cavity, perhaps they produce more higher Q.Interesting. I'd like to see a simulation of what a doppler shift does to the RF in the cavity, forward/reverse paths mode-split or something. If it takes an hour to FDTD simulate a few dozen nanoseconds, is it 100 years to simulate a dozen milliseconds?Oh well.There's another graph that was posted here, showing frequency and modes "Shawyer Conical Resonant Cavity Modes-2 (4).jpg". Couldn't find it using search, here it is again:
I'm just looking for a possible hybrid mode on cavity. But it is not so easy.There are some possibles candidates on Nasa's paper.Some formulas of sensitivity can be used for adjust the dimensions of cavity and to control the frequencys.Very cool.By the way. In corrugated waveguides, hybrid modes have very low losses. In cavity, perhaps they produce more higher Q.
Ok, so from previous posts by aero, I was able to find the Bradycone3D.ctl file used for the meep run. I have now also contacted the FEFF project requesting access to their MEEP AMI. Assuming they agree to this request, I can then start to run the simulation in an Amazon EC2 instance where the concerns of wives and whatnot will not influence the possible computation length, and so will be able to run over thousands of cycles.
Quote from: dumbo on 07/12/2015 04:14 amAssuming they agree to this request, I can then start to run the simulation in an Amazon EC2 instance where the concerns of wives and whatnot will not influence the possible computation length, and so will be able to run over thousands of cycles.It seems you are serious. So use the right model, the one for which Dr. Rodal has already performed a significant analysis on the short time runs.
Assuming they agree to this request, I can then start to run the simulation in an Amazon EC2 instance where the concerns of wives and whatnot will not influence the possible computation length, and so will be able to run over thousands of cycles.
Quote from: aero on 07/12/2015 05:13 amQuote from: dumbo on 07/12/2015 04:14 amAssuming they agree to this request, I can then start to run the simulation in an Amazon EC2 instance where the concerns of wives and whatnot will not influence the possible computation length, and so will be able to run over thousands of cycles.It seems you are serious. So use the right model, the one for which Dr. Rodal has already performed a significant analysis on the short time runs. Let me know if/when you need an AWS account.
It seems you are serious. So use the right model, the one for which Dr. Rodal has already performed a significant analysis on the short time runs. It is a model of rfmwguy's NSF-1701 cavity. It is attached, and is set to produce output.A few points. Line 76 names the output directoryLine 230 "cc" defines the number of cycles to run currently set to 32. We need to decide how much data is needed.Line 251 starts the output data flowfollowed by 6 lines naming the field types and output frequency.I have not yet discovered how to turn the output off, after turning it on but that is something that you will likely need. A 13 cycle .h5 data set of 14 time slices of one field component, (1.4 cycles) is 1.9 GB, so the six components weigh in at about 11.4 GB. Not really something you'd want to upload to many times but needed every so often.
I would suggest to every EMDrive builder that having a Vector Network Analyser and understanding what it is telling you is critical to your success.Doing 1 cable SLOW sweeps can test your excitation antenna design, impedance matching, find your cavity resonances, peak return loss dBs, VSWR, reflection coefficient, Q and cavity bandwidth.Without a VNA, it is hard to understand how any build could achieve Force generation as there are so many VNA determinant / measurable variables that need to be all as close as possible to optimum values.My soon to arrive 100W Rf amp has the ability to be throttled from 50dBm (100W) output to 19dBm (79mW) output and has a real time analogue VSWR output pin, which I plan to use to generate a DIY VNA as knowing the VSWR, Rf amp impedance and the frequency will enable real time calculation of the return loss db, the reflection coefficient, how well the cavity is impedance matched to the Rf amp, the cavity unloaded Q and Q bandwidth.http://cgi.www.telestrian.co.uk/cgi-bin/www.telestrian.co.uk/vswr.plSeems a lot of information to get from 1 pin of analogue information, but the Rf amp is driving the cavity at it's impedance, output frequency and reporting on what is happening via the VSWR analogue output. Additionally doing it this way ensures each EMDrive is impedance matched as close as possible to it's 100W Rf amp.Comments from the experienced microwave guys that have used 1 cable VNA measurements most welcome.
Quote from: TheTraveller on 07/12/2015 09:13 amI would suggest to every EMDrive builder that having a Vector Network Analyser and understanding what it is telling you is critical to your success.Doing 1 cable SLOW sweeps can test your excitation antenna design, impedance matching, find your cavity resonances, peak return loss dBs, VSWR, reflection coefficient, Q and cavity bandwidth.Without a VNA, it is hard to understand how any build could achieve Force generation as there are so many VNA determinant / measurable variables that need to be all as close as possible to optimum values.My soon to arrive 100W Rf amp has the ability to be throttled from 50dBm (100W) output to 19dBm (79mW) output and has a real time analogue VSWR output pin, which I plan to use to generate a DIY VNA as knowing the VSWR, Rf amp impedance and the frequency will enable real time calculation of the return loss db, the reflection coefficient, how well the cavity is impedance matched to the Rf amp, the cavity unloaded Q and Q bandwidth.http://cgi.www.telestrian.co.uk/cgi-bin/www.telestrian.co.uk/vswr.plSeems a lot of information to get from 1 pin of analogue information, but the Rf amp is driving the cavity at it's impedance, output frequency and reporting on what is happening via the VSWR analogue output. Additionally doing it this way ensures each EMDrive is impedance matched as close as possible to it's 100W Rf amp.Comments from the experienced microwave guys that have used 1 cable VNA measurements most welcome.Agreed but a 1 port measurement is simply return loss or an antenna measurement not a bandpass cavity where a sample port is needed for S21. call it reflected S11 Q not forward S21 Q. This will give unnaturally high numbers leading to confusion. If u get the chance, ask shawyer for S21 plots since he had a sample port. This should illustrate assymetrical bandpass response.
Quote from: rfmwguy on 07/12/2015 12:40 pmQuote from: TheTraveller on 07/12/2015 09:13 amI would suggest to every EMDrive builder that having a Vector Network Analyser and understanding what it is telling you is critical to your success.Doing 1 cable SLOW sweeps can test your excitation antenna design, impedance matching, find your cavity resonances, peak return loss dBs, VSWR, reflection coefficient, Q and cavity bandwidth.Without a VNA, it is hard to understand how any build could achieve Force generation as there are so many VNA determinant / measurable variables that need to be all as close as possible to optimum values.My soon to arrive 100W Rf amp has the ability to be throttled from 50dBm (100W) output to 19dBm (79mW) output and has a real time analogue VSWR output pin, which I plan to use to generate a DIY VNA as knowing the VSWR, Rf amp impedance and the frequency will enable real time calculation of the return loss db, the reflection coefficient, how well the cavity is impedance matched to the Rf amp, the cavity unloaded Q and Q bandwidth.http://cgi.www.telestrian.co.uk/cgi-bin/www.telestrian.co.uk/vswr.plSeems a lot of information to get from 1 pin of analogue information, but the Rf amp is driving the cavity at it's impedance, output frequency and reporting on what is happening via the VSWR analogue output. Additionally doing it this way ensures each EMDrive is impedance matched as close as possible to it's 100W Rf amp.Comments from the experienced microwave guys that have used 1 cable VNA measurements most welcome.Agreed but a 1 port measurement is simply return loss or an antenna measurement not a bandpass cavity where a sample port is needed for S21. call it reflected S11 Q not forward S21 Q. This will give unnaturally high numbers leading to confusion. If u get the chance, ask shawyer for S21 plots since he had a sample port. This should illustrate assymetrical bandpass response.What are your thoughts on this solution?http://www.ebay.com/itm/138M-4-4G-SMA-signal-source-generator-simple-spectrum-analyzer-Tracking-source-/111493176997?pt=LH_DefaultDomain_0&hash=item19f582dea5Add a couple of SMA 3dB attenuators for mismatch.Add a sampling port to the frustum with the software and a laptop it should do what needs to be done.(much thanks to someone that has been a wonderful source of information saving me hours of research) Shell
Quote from: apoc2021 on 07/11/2015 08:03 pm@aero et al - regarding longer MEEP runs...Thanks. If someone has done it, that means running meep on the cloud is possible. Good to know. ...
@aero et al - regarding longer MEEP runs...
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Quote from: Rodal on 07/11/2015 06:01 pmThis was discussed back in May:http://forum.nasaspaceflight.com/index.php?topic=36313.msg1369553#msg1369553Quote from: Rodal Paul March has addressed and explained this as follows: Chinese (Prof. Yang) calculated loaded Q factors are much higher than the Q's reported by Shawyer and by NASA' Eagleworks because of the unorthodox way that the Chinese calculate their loaded Q factors. Instead of using the S11 zero dB reference plane to measure their -3dB down bandwidths from, as is done elsewhere, the Chinese use the most negative dB S11 value located at the resonance frequency and measure up 3dB toward the S11 zero dB plane. Therefore, of course, the bandwidth figures used by the Chinese in this unorthodox calculation are going to be ridiculously small which yields correspondingly artificially large values of the calculated Q-factor. .Here is where they went wrong...under no industrial RF standard does anyone measure Q on return loss, S11. It is done on S21, forward power in the frequency domain for cavities. I stand by my claim that "Specsmanship" was used to create an unnaturally large Q, either by unfamiliarity or intent.Note that S21 requires a 2 port measurement, input and output (note the sampling port on the frustums will provide the output). I'd bet a six-pack of craft beer that realistic Qs are in the 4 digit range for both shawyer and yang. And yes Doc, Yang should have used the -3dB points below 0 insertion, not -3dB above best return loss...not RF types IMHO.
This was discussed back in May:http://forum.nasaspaceflight.com/index.php?topic=36313.msg1369553#msg1369553Quote from: Rodal Paul March has addressed and explained this as follows: Chinese (Prof. Yang) calculated loaded Q factors are much higher than the Q's reported by Shawyer and by NASA' Eagleworks because of the unorthodox way that the Chinese calculate their loaded Q factors. Instead of using the S11 zero dB reference plane to measure their -3dB down bandwidths from, as is done elsewhere, the Chinese use the most negative dB S11 value located at the resonance frequency and measure up 3dB toward the S11 zero dB plane. Therefore, of course, the bandwidth figures used by the Chinese in this unorthodox calculation are going to be ridiculously small which yields correspondingly artificially large values of the calculated Q-factor. .
Paul March has addressed and explained this as follows: Chinese (Prof. Yang) calculated loaded Q factors are much higher than the Q's reported by Shawyer and by NASA' Eagleworks because of the unorthodox way that the Chinese calculate their loaded Q factors. Instead of using the S11 zero dB reference plane to measure their -3dB down bandwidths from, as is done elsewhere, the Chinese use the most negative dB S11 value located at the resonance frequency and measure up 3dB toward the S11 zero dB plane. Therefore, of course, the bandwidth figures used by the Chinese in this unorthodox calculation are going to be ridiculously small which yields correspondingly artificially large values of the calculated Q-factor. .
I would suggest to every EMDrive builder that having a Vector Network Analyser and understanding what it is telling you is critical to your success....a real time analogue VSWR output pin, which I plan to use to generate a DIY VNA as knowing the VSWR, Rf amp impedance and the frequency will enable real time calculation of the return loss db, the reflection coefficient, how well the cavity is impedance matched to the Rf amp, the cavity unloaded Q and Q bandwidth....Comments from the experienced microwave guys that have used 1 cable VNA measurements most welcome.