Quote from: Prunesquallor on 06/14/2015 04:28 pmQuote from: RareSaturn on 06/14/2015 10:24 amData from second Baby EmDrive testhttps://hackaday.io/project/5596-em-drive/log/19468-torsion-test-2-dataUsing their data, I plotted maxima and minima, then averaged: ave(t) = [min(t)+max(t-1)]/2. Thruster on/off times were interpreted from hackaday plot.As others have said you would need to perform proper signal / time series analysis on this to be sure.Maybe something that could be useful for a start is if to compute the average the Ys for the periods where the drive is "off" and then for the period where the drive is "on". Is there any noticeable pattern ?
Quote from: RareSaturn on 06/14/2015 10:24 amData from second Baby EmDrive testhttps://hackaday.io/project/5596-em-drive/log/19468-torsion-test-2-dataUsing their data, I plotted maxima and minima, then averaged: ave(t) = [min(t)+max(t-1)]/2. Thruster on/off times were interpreted from hackaday plot.
Data from second Baby EmDrive testhttps://hackaday.io/project/5596-em-drive/log/19468-torsion-test-2-data
I do see a half-decent anticorrelation now, on the 2nd half.But I won't eat my hat until I see a similar set of data with the cavity reversed.
Quote from: deuteragenie on 06/14/2015 06:51 pmQuote from: Prunesquallor on 06/14/2015 04:28 pmQuote from: RareSaturn on 06/14/2015 10:24 amData from second Baby EmDrive testhttps://hackaday.io/project/5596-em-drive/log/19468-torsion-test-2-dataUsing their data, I plotted maxima and minima, then averaged: ave(t) = [min(t)+max(t-1)]/2. Thruster on/off times were interpreted from hackaday plot.As others have said you would need to perform proper signal / time series analysis on this to be sure.Maybe something that could be useful for a start is if to compute the average the Ys for the periods where the drive is "off" and then for the period where the drive is "on". Is there any noticeable pattern ?Since I already had this plotted, it was pretty easy. And more interesting, especially the second half of the test. Comments?
Quote from: deltaMass on 06/14/2015 08:45 pmI do see a half-decent anticorrelation now, on the 2nd half.But I won't eat my hat until I see a similar set of data with the cavity reversed.I see here a stock market that is looking pretty good right now, with a great trend, it looks like great momentum for trading:Oh , no sorry, that's a random walk of 10,000 coin tosses
Since I already had this plotted, it was pretty easy. And more interesting, especially the second half of the test. Comments?
...Another thing is to do some autocorrelation analysis on the TS. R has what you need.
Quote from: Star One on 06/13/2015 02:36 pmSecond test of the baby EM drive and problems with oscillation. I think they are looking for suggestions to resolve this?https://www.youtube.com/watch?v=Y8uyIgzdzS4&feature=youtu.beMore info.https://hackaday.io/project/5596-em-drive/log/19417-torsion-test-no-data-due-to-oscillationsMy guess is the pendulum is being excited by vibrations. Even the smallest vibration or movement of the whole apparatus will make the pendulum swing back and forth at its natural frequency. This effect is much more noticeable than any possible thrust from the RF. A method used by holography experimenters is to use a container filled with sand as the base, and have that container situated on a concrete floor. The apparatus has legs that are sunk into the sand. Any table or floor of a wood frame house will be swaying from vibrations, wind outside, etc. This movement is coupled to the whole apparatus, making the pendulum swing. But the effect of seismic activity, waves crashing on a distant shoreline, heavy trucks passing, construction activity, etc, etc, will still affect the measurement. Any thrust from the RF will always be too far below the noise level to even be measured, no matter what methods are used to analyze the "data".
Second test of the baby EM drive and problems with oscillation. I think they are looking for suggestions to resolve this?https://www.youtube.com/watch?v=Y8uyIgzdzS4&feature=youtu.beMore info.https://hackaday.io/project/5596-em-drive/log/19417-torsion-test-no-data-due-to-oscillations
Quote from: deuteragenie on 06/14/2015 09:05 pm...Another thing is to do some autocorrelation analysis on the TS. R has what you need.I was showing that the human mind is built by Nature to see patterns, many times where there may not be any patterns. (The face on Mars, trees on Mars, etc.)
Quote from: deuteragenie on 06/14/2015 09:05 pm...Another thing is to do some autocorrelation analysis on the TS. R has what you need.Focusing on the Movax experiment, they should try to use oil (instead of water) to dampen the vibrations.
Quote from: zen-in on 06/14/2015 05:12 pmQuote from: Star One on 06/13/2015 02:36 pmSecond test of the baby EM drive and problems with oscillation. I think they are looking for suggestions to resolve this?https://www.youtube.com/watch?v=Y8uyIgzdzS4&feature=youtu.beMore info.https://hackaday.io/project/5596-em-drive/log/19417-torsion-test-no-data-due-to-oscillationsMy guess is the pendulum is being excited by vibrations. Even the smallest vibration or movement of the whole apparatus will make the pendulum swing back and forth at its natural frequency. This effect is much more noticeable than any possible thrust from the RF. A method used by holography experimenters is to use a container filled with sand as the base, and have that container situated on a concrete floor. The apparatus has legs that are sunk into the sand. Any table or floor of a wood frame house will be swaying from vibrations, wind outside, etc. This movement is coupled to the whole apparatus, making the pendulum swing. But the effect of seismic activity, waves crashing on a distant shoreline, heavy trucks passing, construction activity, etc, etc, will still affect the measurement. Any thrust from the RF will always be too far below the noise level to even be measured, no matter what methods are used to analyze the "data".Another option might be to approach this in a manner similar to noise canceling microphones: construct a second "null" apparatus (with identical design, mass distribution, etc) and then collect simultaneous data from both the "null" apparatus and the "baby EM drive" apparatus. Unfortunately the DIY nature of their current torsion apparatus probably precludes such a technique. If the apparatus was redesigned, running a simultaneous twin "null" for noise correlation might enable recovery of some signal-to-noise ratio.However, I suspect there are also chaotic air currents in play, which probably won't correlate in a twin "null" configuration. A bit more control over their testing environment is probably worthwhile. (i.e. attempts to isolate apparatus from vibrations, air currents, etc)I imagine Paul March could give us a few stories about noise sources in his pursuit of EM drive SNR.
Here's some shabby analysis. If I saw anything I would've gone deeper!
If the thruster is powerful enough to cause the device to rocket out of sight in seconds, then the noise may not be a factor. If the goal is to minimize noise and record a small signal, the best strategy is to rigidly mount to device on a load cell anchored to a vibration-isolated table. A device that is free to move will be subject to motion due to noise, air currents, both already present and thermally induced, thermal recoil, power line induced magnetic fields, vibrations from air conditioners, traffic, and distant earthquakes, and a host of other factors. The investigator's statement that the device has to be free to move or there would be no thrust is unfortunately a misinterpretation of Newton's laws.
Quote from: deuteragenie on 06/14/2015 09:05 pm...Another thing is to do some autocorrelation analysis on the TS. R has what you need.I was showing that the human mind is built by Nature to see patterns, many times where there may not be any patterns. (The face on Mars, trees on Mars, etc.)...Focusing on the Movax experiment, they should try to use oil (instead of water) to dampen the vibrations.If calculate we must, calculate we will. We can also do autocorrelation and power spectral density with Mathematica:(I guess we could also try to do a cross-correlation with the on/off signal later on...)