One other interesting thing I found was that many of the extremely large Q frustums can be brought back into line with predicted values by simply dividing the provided Q value by 10.

Quote from: tleach on 08/07/2015 06:43 PMOne other interesting thing I found was that many of the extremely large Q frustums can be brought back into line with predicted values by simply dividing the provided Q value by 10. Why would you do that?The Demonstrator EMDrive has a stated Q of 45,000 and Df of 0.844.The data is what it is.

Quote from: TheTraveller on 08/07/2015 07:04 PMQuote from: tleach on 08/07/2015 06:43 PMOne other interesting thing I found was that many of the extremely large Q frustums can be brought back into line with predicted values by simply dividing the provided Q value by 10. Why would you do that?The Demonstrator EMDrive has a stated Q of 45,000 and Df of 0.844.The data is what it is.Obviously Q isn't Q if everybody's measuring it differently and getting different values.But mostly, I noticed a trend and thought it was interesting. There was so much controversy swirling around with the whole "how do you calculate Q" thing, and since Q is an integral part of the McCulloch equation I thought I'd play around with it a bit.

Quote from: TheTraveller on 08/07/2015 07:04 PMQuote from: tleach on 08/07/2015 06:43 PMOne other interesting thing I found was that many of the extremely large Q frustums can be brought back into line with predicted values by simply dividing the provided Q value by 10. Why would you do that?The Demonstrator EMDrive has a stated Q of 45,000 and Df of 0.844.The data is what it is.Because, as we've tried to explain countless times, the Qs in Yang/Shell were grossly overstated. I think Thor is generous when he only divides it by 10.Want proof? Look at Tajmar's Q, then look at yang/shawyers and tell me why there is a so much disparity. The disparity lies in yang/shawyers unfamiliarity with cavity Q measurement.

Quote from: tleach on 08/07/2015 07:13 PMQuote from: TheTraveller on 08/07/2015 07:04 PMQuote from: tleach on 08/07/2015 06:43 PMOne other interesting thing I found was that many of the extremely large Q frustums can be brought back into line with predicted values by simply dividing the provided Q value by 10. Why would you do that?The Demonstrator EMDrive has a stated Q of 45,000 and Df of 0.844.The data is what it is.Obviously Q isn't Q if everybody's measuring it differently and getting different values.But mostly, I noticed a trend and thought it was interesting. There was so much controversy swirling around with the whole "how do you calculate Q" thing, and since Q is an integral part of the McCulloch equation I thought I'd play around with it a bit.In the experimental EMDrive world of Shawyer, Prof Yang, Eagleworks and Tajmar, unloaded Q is measured and reported as the 3dB down bandwidth from the max return loss dB divided into the resonant frequency.As Tajmar reported in the attachment.

They all measure their unloaded Q the same way.Measured resonant frequency at max return loss dB / bandwidth at 3dB down from the peak return loss dBs.Examples from Eagleworks, Tajmar and Prof Yang. All using the same method to calc unloaded Q.

I will take the time to explain this one more time, Mr T. after that, either you are deliberately trying to confuse the issue or you simply cannot comprehend.Q = Ctr freq of resonance/3dB bandwidth (total half power bandwidth). Return loss has no bearing on a Q measurement, it MUST be a 2 port measurement, otherwise it is a single-port device akin to an antenna, not a cavity. The calculations used in virtually all relative RF and Microwave circuits calculate Q in the same way, not what yang/shawyer invented.http://docs.lumerical.com/en/diffractive_optics_cavity_q_calculation.html"High Q cavitiesDerivation of Q factor formula:The quality factor (Q) is defined as (see image) where wr is the resonant frequency ( ωr=2π fR) and FWHM is the full width half max of the resonance intensity spectrum."

Quote from: TheTraveller on 08/07/2015 07:31 PMThey all measure their unloaded Q the same way.Measured resonant frequency at max return loss dB / bandwidth at 3dB down from the peak return loss dBs.Examples from Eagleworks, Tajmar and Prof Yang. All using the same method to calc unloaded Q.You are absolutely, 100% right. I hereby defer to you in all future disagreements. I apologize for my impertinence. My spreadsheet is wrong and your spreadsheet is right.

The calculations used in virtually all relative RF and Microwave circuits calculate Q in the same way, not what yang/shawyer invented.

The testiness of this current discussion aside, I am genuinely interested in the reason why there is a difference between these two Q value viewpoints.