-
#1400 by rfmwguy on 07 Jan, 2016 13:50
-
Tangential - Emdrive forums from around the globe Volume I
Found this Russian forum interesting. Typical back and forth general opinions (minus data). Did note the moderator chimes in a lot with "Invalid Tone" warnings. See, its not so bad here
Translated into English: https://translate.google.com/translate?hl=en&sl=ru&u=http://www.sciteclibrary.ru/cgi-bin/yabb2/YaBB.pl%3Fnum%3D1447076750/450&prev=search
My favorite mod alert is: "I warn you in connection with the rough treatment to the interlocutors."
-
#1401 by rfmwguy on 07 Jan, 2016 14:03
-
I did not take this seriously Doc. Never tried it for observational testing. Can't say whether there's any validity. The deliberate introduction of vibration/motion beyond thermal lift didn't seem to make sense. So my humble opinion is...nope. Nothing I think is beneficial...but...simple to confirm I guess.
I recall that some time ago someone quoted Shawyer as stating now that his experiments show no force unless some amount of vibration was present in the experiments.
Just like this:The physics of the EM drive is well defined but unfortunately it is not what the inventor claims.
Also the inventor's video demo on Youtube shows EM drive rotating in the opposite direction than what his theory claim.
The EmDrives moves / generates Force toward the small end, as it does in the video.
http://forum.nasaspaceflight.com/index.php?topic=37642.msg1409361#msg1409361
https://forum.nasaspaceflight.com/index.php?topic=37642.msg1397204#msg1397204
http://forum.nasaspaceflight.com/index.php?topic=37642.msg1397386#msg1397386
http://forum.nasaspaceflight.com/index.php?topic=37642.msg1397370#msg1397370
When asked what frequency and amplitude of vibration was "necessary", there was no reply that I recall. I have not heard discussion of this need to impose vibration recently.
What is the latest information in this regard?
Is the need for vibration still being claimed?
Has this claim for need of vibration been abandoned?
What is the view of people doing Do It Yourself experiments in regards to this claim for the need of vibrations?
If this claim has been abandoned, it would be good to put this matter to a close, for clarity purposes. -
#1402 by Rodal on 07 Jan, 2016 14:06
-
Thank you for your answer, as the reading public needs clarity.
I did not take this seriously Doc. Never tried it for observational testing. Can't say whether there's any validity. The deliberate introduction of vibration/motion beyond thermal lift didn't seem to make sense. So my humble opinion is...nope. Nothing I think is beneficial...but...simple to confirm I guess.
I recall that some time ago someone quoted Shawyer as stating now that his experiments show no force unless some amount of vibration was present in the experiments.
Just like this:The physics of the EM drive is well defined but unfortunately it is not what the inventor claims.
Also the inventor's video demo on Youtube shows EM drive rotating in the opposite direction than what his theory claim.
The EmDrives moves / generates Force toward the small end, as it does in the video.
http://forum.nasaspaceflight.com/index.php?topic=37642.msg1409361#msg1409361
https://forum.nasaspaceflight.com/index.php?topic=37642.msg1397204#msg1397204
http://forum.nasaspaceflight.com/index.php?topic=37642.msg1397386#msg1397386
http://forum.nasaspaceflight.com/index.php?topic=37642.msg1397370#msg1397370
When asked what frequency and amplitude of vibration was "necessary", there was no reply that I recall. I have not heard discussion of this need to impose vibration recently.
What is the latest information in this regard?
Is the need for vibration still being claimed?
Has this claim for need of vibration been abandoned?
What is the view of people doing Do It Yourself experiments in regards to this claim for the need of vibrations?
If this claim has been abandoned, it would be good to put this matter to a close, for clarity purposes.
Now, do others ( TT , Shell, etc.) also share your opinion ?
What past reported experiments, private, institutional, DIY (if any) have included forced vibration ?
Is forced vibration present in other's planned future test program for DoItYourself experiments ? -
#1403 by TheTraveller on 07 Jan, 2016 14:21
-
If this claim has been abandoned, it would be good to put this matter to a close, for clarity purposes.
Please reread what was stated:
http://www.emdrive.com/EmDriveForceMeasurement.pdf
Basically says if you attempt and succeed in the elimination of all external forces (vibration) and the EmDrive is restrained from being able to move, there may not be any measurable force generated.
Suggest all the test rigs that have been built would have some external forces being applied to the frustum, even if just acoustic energy hitting the frustum end plates.
As for the min amount of external Force required, I have never asked the question as my test rig is rotary and allows continual acceleration. The note applied to frustums that were tightly restrained and acceleration / movement was potential non existant or very constrained.
The note exists because apparently for some EmDrive experimenters test setups, the issues addressed were relevant. However what most here are doing in their experimental test setups, the note would not apply.
It may however apply to a highly vibration isolated test setup operated in a high vacuum where the EmDrive is restrained from being able to move / accelerate. -
#1404 by TheTraveller on 07 Jan, 2016 14:30
-
Thank you for your answer, as the reading public needs clarity.
I did not take this seriously Doc. Never tried it for observational testing. Can't say whether there's any validity. The deliberate introduction of vibration/motion beyond thermal lift didn't seem to make sense. So my humble opinion is...nope. Nothing I think is beneficial...but...simple to confirm I guess.
I recall that some time ago someone quoted Shawyer as stating now that his experiments show no force unless some amount of vibration was present in the experiments.
Just like this:The physics of the EM drive is well defined but unfortunately it is not what the inventor claims.
Also the inventor's video demo on Youtube shows EM drive rotating in the opposite direction than what his theory claim.
The EmDrives moves / generates Force toward the small end, as it does in the video.
http://forum.nasaspaceflight.com/index.php?topic=37642.msg1409361#msg1409361
https://forum.nasaspaceflight.com/index.php?topic=37642.msg1397204#msg1397204
http://forum.nasaspaceflight.com/index.php?topic=37642.msg1397386#msg1397386
http://forum.nasaspaceflight.com/index.php?topic=37642.msg1397370#msg1397370
When asked what frequency and amplitude of vibration was "necessary", there was no reply that I recall. I have not heard discussion of this need to impose vibration recently.
What is the latest information in this regard?
Is the need for vibration still being claimed?
Has this claim for need of vibration been abandoned?
What is the view of people doing Do It Yourself experiments in regards to this claim for the need of vibrations?
If this claim has been abandoned, it would be good to put this matter to a close, for clarity purposes.
Now, do others ( TT , Shell, etc.) also share your opinion ?
What past reported experiments, private, institutional, DIY (if any) have included forced vibration ?
Is forced vibration present in other's planned future test program for DoItYourself experiments ?
Dave,
It is not an issue about forcing vibrations to be present so much as a word of caution as to what might happen to a highly movement constrained EmDrive that was ALSO operated in an environment where all vibration had been eliminated.
The 2 required test setup conditions don't seem to apply to any EmDrive test setup I know of.
Phil -
#1405 by rfmwguy on 07 Jan, 2016 14:36
-
OK Phil, seems to clarify it. Vertical lift will start fairly quickly on a balance beam anyway, so never thought about the tap to "unlock" stickiness. Fortunately, the knife edge thing I used showed little if any.
Remember the galinstan I tried? NOT a good idea...the surface tension and the resistance was FAR more than I anticipated. I used this to supply power from the mw box to the frustum...anyone want a few ounces of galinstan?
-
#1406 by zellerium on 07 Jan, 2016 14:41
-
Thank you for your answer, as the reading public needs clarity.
I did not take this seriously Doc. Never tried it for observational testing. Can't say whether there's any validity. The deliberate introduction of vibration/motion beyond thermal lift didn't seem to make sense. So my humble opinion is...nope. Nothing I think is beneficial...but...simple to confirm I guess.
I recall that some time ago someone quoted Shawyer as stating now that his experiments show no force unless some amount of vibration was present in the experiments.
Just like this:The physics of the EM drive is well defined but unfortunately it is not what the inventor claims.
Also the inventor's video demo on Youtube shows EM drive rotating in the opposite direction than what his theory claim.
The EmDrives moves / generates Force toward the small end, as it does in the video.
http://forum.nasaspaceflight.com/index.php?topic=37642.msg1409361#msg1409361
https://forum.nasaspaceflight.com/index.php?topic=37642.msg1397204#msg1397204
http://forum.nasaspaceflight.com/index.php?topic=37642.msg1397386#msg1397386
http://forum.nasaspaceflight.com/index.php?topic=37642.msg1397370#msg1397370
When asked what frequency and amplitude of vibration was "necessary", there was no reply that I recall. I have not heard discussion of this need to impose vibration recently.
What is the latest information in this regard?
Is the need for vibration still being claimed?
Has this claim for need of vibration been abandoned?
What is the view of people doing Do It Yourself experiments in regards to this claim for the need of vibrations?
If this claim has been abandoned, it would be good to put this matter to a close, for clarity purposes.
Now, do others ( TT , Shell, etc.) also share your opinion ?
What past reported experiments, private, institutional, DIY (if any) have included forced vibration ?
Is forced vibration present in other's planned future test program for DoItYourself experiments ?
Isn't everything above 0K in a state of vibration?
Or is this forced vibration somehow directional? -
#1407 by Rodal on 07 Jan, 2016 14:42
-
OK Phil, seems to clarify it. Vertical lift will start fairly quickly on a balance beam anyway, so never thought about the tap to "unlock" stickiness. Fortunately, the knife edge thing I used showed little if any.
Well, having worked in dynamics of structures all my life, from my PhD research at MIT to my professional experience (including vibration measurements in industrial equipment and successfully addressing self-excited vibration problems), I can state that <<what might happen to a highly movement constrained EmDrive that was ALSO operated in an environment where all vibration had been eliminated>> does not really clarify much because these words don't have much engineering meaning to somebody experienced with vibration and dynamics of structures, as practically all structures ([whether on the Earth's surface or in space) have some finite amount of vibration amplitude.
Remember the galinstan I tried? NOT a good idea...the surface tension and the resistance was FAR more than I anticipated. I used this to supply power from the mw box to the frustum...anyone want a few ounces of galinstan?
As NSF is an aerospace forum, frequented by many aerospace engineers that are knowledgeable of this fact (just imagine how much effort an aerospace engineer has to put in designing a space telescope to address this issue !, or how aerospace engineers are knowledgeable of self-excited vibrations in rocket propulsion ) and they understand this issue well, I will drop further discussion of this for the time being 
.
-
#1408 by rfmwguy on 07 Jan, 2016 14:50
-
No need to Doc, if you think it is worth pursuing its fine. Since this forum is a record of testing, etc., anything you feel is warranted is certainly applicable to experimenters down the road.OK Phil, seems to clarify it. Vertical lift will start fairly quickly on a balance beam anyway, so never thought about the tap to "unlock" stickiness. Fortunately, the knife edge thing I used showed little if any.
Well, having worked in dynamics of structures all my life, from my PhD research at MIT to my professional experience (including vibration measurements in industrial equipment and addressing self-excited vibration), I can state that <<what might happen to a highly movement constrained EmDrive that was ALSO operated in an environment where all vibration had been eliminated.>> does not really clarify much because these words don't have much engineering meaning as practically all structures (whether on the Earth's surface or in space) have some finite amount of vibration.
Remember the galinstan I tried? NOT a good idea...the surface tension and the resistance was FAR more than I anticipated. I used this to supply power from the mw box to the frustum...anyone want a few ounces of galinstan?
As NSF is an aerospace forum, frequented by many aerospace engineers that are knowledgeable of this fact (just imagine how much effort an aerospace engineer has to put in designing a space telescope to address this issue !, or how aerospace engineers are knowledgeable of self-excited vibrations in rocket propulsion ) and they understand this issue well, I will drop further discussion of this for the time being .
Actually, I think you don't give yourselves enough credit for suggestions to eliminate experimental/testing errors...some of us haven't had to consider this for MANY years. Keep on going at your discretion.
My QA test engineering for RF signal sources was Wavetek (JDSU) 1979 - 1981...then off to app/sales engineering, so lots of cobwebs here
-
#1409 by SeeShells on 07 Jan, 2016 15:53
-
I remember the conversations on a vibration was needed to get the effect working. And some of the test stand was designed to look for and isolate vibrations. While I didn't specifically look for anything other than to see if it would power up the design steps were still in place.
Thank you for your answer, as the reading public needs clarity.
I did not take this seriously Doc. Never tried it for observational testing. Can't say whether there's any validity. The deliberate introduction of vibration/motion beyond thermal lift didn't seem to make sense. So my humble opinion is...nope. Nothing I think is beneficial...but...simple to confirm I guess.
I recall that some time ago someone quoted Shawyer as stating now that his experiments show no force unless some amount of vibration was present in the experiments.
Just like this:The physics of the EM drive is well defined but unfortunately it is not what the inventor claims.
Also the inventor's video demo on Youtube shows EM drive rotating in the opposite direction than what his theory claim.
The EmDrives moves / generates Force toward the small end, as it does in the video.
http://forum.nasaspaceflight.com/index.php?topic=37642.msg1409361#msg1409361
https://forum.nasaspaceflight.com/index.php?topic=37642.msg1397204#msg1397204
http://forum.nasaspaceflight.com/index.php?topic=37642.msg1397386#msg1397386
http://forum.nasaspaceflight.com/index.php?topic=37642.msg1397370#msg1397370
When asked what frequency and amplitude of vibration was "necessary", there was no reply that I recall. I have not heard discussion of this need to impose vibration recently.
What is the latest information in this regard?
Is the need for vibration still being claimed?
Has this claim for need of vibration been abandoned?
What is the view of people doing Do It Yourself experiments in regards to this claim for the need of vibrations?
If this claim has been abandoned, it would be good to put this matter to a close, for clarity purposes.
Now, do others ( TT , Shell, etc.) also share your opinion ?
What past reported experiments, private, institutional, DIY (if any) have included forced vibration ?
Is forced vibration present in other's planned future test program for DoItYourself experiments ?
The pre-loaded digital scales showed a stable environment with no fluctuations. The scales sampling rate was 1/10 sec well within the harmonics of the beam. The center magnetron/beam knife egde floor stand was on 1/2" sorbathane vibration pads isolating the DUT from floor vibrations. A Faraday cage with additional plastic sheeting in the view windows to prevent air currents from adding movement. Magnetron isolated from the frustum.
Although vibration elements could have been present in sound. I've also double insulated the room with that same double bubble insulating rolls I used in the shop that's a very good sound dampener.
I would say chances that an external vibration element effecting the frustum was very low.
Shell
PS: I did holler loudly a few times but it was already doing something, so it doesn't count. -
#1410 by Tellmeagain on 07 Jan, 2016 16:15
-
I recall that some time ago someone claimed that Shawyer stated that his experiments show no force unless some amount of forced external vibration was imparted in the experiments (or similar words to that effect). Going by memory, these are some of the messages I found by a rapid search:
http://forum.nasaspaceflight.com/index.php?topic=37642.msg1409361#msg1409361
https://forum.nasaspaceflight.com/index.php?topic=37642.msg1397204#msg1397204
http://forum.nasaspaceflight.com/index.php?topic=37642.msg1397386#msg1397386
http://forum.nasaspaceflight.com/index.php?topic=37642.msg1397370#msg1397370
https://forum.nasaspaceflight.com/index.php?topic=37642.msg1401205#msg1401205
It was claimed that forced external vibration " enables switch from IDLE to MOTOR mode" of the EM Drive.
When asked what frequency and amplitude of vibration was "necessary", there was no reply that I recall. I have not heard discussion of this need to impose vibration recently.
What is the latest information in this regard?
Is the need for vibration still being claimed?
Has this claim for need of vibration been abandoned?
What is the view of people doing Do It Yourself experiments in regards to this claim for the need of vibrations?
Are they including forced vibration in their experiments?
If this claim has been abandoned, it would be good to put this matter to a close, for clarity purposes.
Take a look of Shawyer's original turning table experiment on YouTube. Surely it needs vibration (or tapping) to overcome the initial static friction. But such a vibration is not needed for a torsion balance or a boat on water experiment to overcome static friction that is zero.
-
#1411 by SeeShells on 07 Jan, 2016 16:21
-
The air bearing this is mounted on is virtually frictionless but he does have fans and pumps running plus the thrumming of the air compressor nearby.
I recall that some time ago someone claimed that Shawyer stated that his experiments show no force unless some amount of forced external vibration was imparted in the experiments (or similar words to that effect). Going by memory, these are some of the messages I found by a rapid search:
http://forum.nasaspaceflight.com/index.php?topic=37642.msg1409361#msg1409361
https://forum.nasaspaceflight.com/index.php?topic=37642.msg1397204#msg1397204
http://forum.nasaspaceflight.com/index.php?topic=37642.msg1397386#msg1397386
http://forum.nasaspaceflight.com/index.php?topic=37642.msg1397370#msg1397370
https://forum.nasaspaceflight.com/index.php?topic=37642.msg1401205#msg1401205
It was claimed that forced external vibration " enables switch from IDLE to MOTOR mode" of the EM Drive.
When asked what frequency and amplitude of vibration was "necessary", there was no reply that I recall. I have not heard discussion of this need to impose vibration recently.
What is the latest information in this regard?
Is the need for vibration still being claimed?
Has this claim for need of vibration been abandoned?
What is the view of people doing Do It Yourself experiments in regards to this claim for the need of vibrations?
Are they including forced vibration in their experiments?
If this claim has been abandoned, it would be good to put this matter to a close, for clarity purposes.
Take a look of Shawyer's original turning table experiment on YouTube. Surely it needs vibration (or tapping) to overcome the initial static friction. But such a vibration is not needed for a torsion balance or a boat on water experiment to overcome static friction that is zero. -
#1412 by Slyver on 07 Jan, 2016 16:35
-
I remember the conversations on a vibration was needed to get the effect working...
If I remember correctly, it has been suggested at some point that this device might be an inertial ratchet. If somehow the inertial mass of this device is greater in one direction than another, an oscillation (vibration) along the same axis as the inertial mass asymmetry would be required for a self-induced thrust.
In any environment but a complete vacuum, a net force would be caused by air pressure acting on a directionally dependent inertial mass. Thus, by the "inertial ratchet" supposition, any measured force would be proportional to the level of vacuum or frequency of induced oscillation along the longitudinal axis.
This may be a possible explanation* for the orders of magnitude reduced anomalous forces measured in vacuum.
*Where I haven’t really explained anything, but rather suggested a direction of inquiry.
-
#1413 by Bob Woods on 07 Jan, 2016 16:42
-
...anyone want a few ounces of galinstan?
You might ask Putin on the Russian forum. They've been involved in a few 'stan's over the centuries.
-
#1414 by Prunesquallor on 07 Jan, 2016 18:18
-
...anyone want a few ounces of galinstan?
Does it make a good mix with Scotch? -
#1415 by Tellmeagain on 07 Jan, 2016 18:37
-
The air bearing this is mounted on is virtually frictionless but he does have fans and pumps running plus the thrumming of the air compressor nearby.
It is not clear to me how the air bearing is done. It looks like an ordinary ball bearing turning table rotating around an axle. Do you have reference on about the air bearing he used in the Youtube static test? -
#1416 by Rodal on 07 Jan, 2016 18:40
-
...anyone want a few ounces of galinstan?
Does it make a good mix with Scotch?
I know that you people are joking, but because this is read by a wide audience I would like to warn the general reader of Galinstan's Material Safety Data Sheet:
http://www.rgmd.com/msds/msds.pdfQuote
4. First aid measures
General: General instructions are not necessary.
Inhalation: Inhalation does not pose any risk.
If the product has come into contact with he skin: Wash affected area with water and soap.
If the product has come into contact with the eyes: Rinse the eyes with lukewarm water, with eyelid opened.
If the product is ingested: Keep cool. Consult a physician and make this Safety Data Sheet available.
Instruction for the physician: Specific measures to be taken are not known or documented. Carry out a
symptomatic therapy.
....
Hand protection:
Wear rubber protective gloves to avoid a repeated or permanent contact with the skin as the product will deplete
skin oils. If necessary, use a skin protective hand lotion.
Eye protection:
Wear eye protection to prevent potential contact with the eyes.
Body protection:
Wear suitable clothing if there is a risk of splashing and potential contact with the body. Prolonged contact can
deplete skin oils.
General composition of Galinstan (this is what you would be ingesting):
Gallium (Ga): 68.5%
Indium (In): 21.5%
Tin (Sn): 10%
gallium is mildly toxic, but is often considered non-toxic. The trouble with gallium is that it wets the skin unlike mercury. it gets into the crevices in your skin and stains.
If you get gallium, you should wear gloves. That way you will not be risking anything.
Here is the NCBI on the toxicity of
Galium: http://www.ncbi.nlm.nih.gov/pubmed/22024274
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2898053/
Indium: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2072430/
and on Tin http://www.ncbi.nlm.nih.gov/pubmed/3291572
And drink the Scotch alone, don't mix it with this stuff
-
#1417 by rfmwguy on 07 Jan, 2016 18:40
-
Well...hope this is not a duplicate post...but have you read Harold "Sonny" White, et al, April 2, 2015 Technical Report available on the public Nasa Server (NTRS)? If not, dig in...if its a dupe post, let me know...I couldn't find it...
Dynamics of the Vacuum and Casimir Analogs to the Hydrogen Atom
Abstract: This paper will discuss the current viewpoint of the vacuum state and explore the idea of a "natural" vacuum as opposed to immutable, non-degradable vacuum. This concept will be explored for all primary quantum numbers to show consistency with observation at the level of Bohr theory. A comparison with the Casimir force per unit area will be made, and an explicit function for the spatial variation of the vacuum density around the atomic nucleus will be derived. This explicit function will be numerically modeled using the industry multi-physics tool, COMSOL(trademark), and the eigenfrequencies for the n = 1 to n = 7 states will be found and compared to expectation.
http://ntrs.nasa.gov/search.jsp?R=20150006842
(edit - url shortened)
p.s. This MIGHT be a "foundation" Report for a peer-reviewed paper rumored to be coming out soon. I have no idea, just a thought. -
#1418 by RFPlumber on 07 Jan, 2016 19:18
-
JFYI, Attached are COMSOL simulations for the frustum (with coax coupling) I am going to build. It is now time for some sheet metal cutting and torch soldering... And then there will be the moment of truth.
D_big: 264 mm
D_small: 158 mm
L_center: 204 mm
TE012 freq: 2,323,xxx kHz COMSOL (vs. 2,402,xxx spreadsheet)
Hi RfPlumber,
Thanks for the data on your test setup and VERY LOW COST quasi VNA. Have ordered that unit as I have built a Forward & Reflected power monitor that should have almost zero insertion loss and should work well with that unit. If it works as expected, using it and this unit will make really low cost frustum resonance monitoring a reality. By low cost I mean like around $150.
Can you please confirm the frustum built length is 204 mm and not 240 mm?
...
Based on the frustum length being 240 mm (TE012 resonance at 2.324 GHz), the prediction is 4mN at unloaded Q of 50k (25k loaded Q) and 30W Rf forward power.
Hi TT,
You're welcome. I am glad this info ends up useful. Yes, all dimensions above are correct, and the center length is 204 mm (and the actual frustum as-built ended up within 1mm of that length). Spreadsheet does produce a different value for TE012 frequency (2,402 MHz) vs. 2,323 MHz per COMSOL, and unfortunately the COMSOL value ends up being much closer to reality.
...4 mN of thrust would send my poor pendulum into an orbitDo you have a link for your 30W Rf amp and can the freq gen you have drive it enough power to obtain the 30Ws at output?
Yes, it is the same unit someone else has recently pointed to. http://www.ebay.com/itm/30W-Class-A-Linear-RF-amplifier-2-3-2-45-GHz-2304-ATV-/221981664579?hash=item33af236543:g:Ro4AAOSw1S9WhALo
Note that it has a rather narrow band (2.30-2.35 GHz) where it can deliver 30W, hence all my trouble to make a frustum with a mode in this range.
No, my freq generator does not have enough power to directly drive this amp (just a few dBm short), so I am using a pre-amp. This one: http://www.ebay.com/itm/Mini-Circuits-Wideband-RF-Amplifier-ZX60-6013E-S-50-20-MHz-to-6-GHz-NOS-/261994189569?hash=item3d00121301:g:2jEAAOSwyQtVwsdG
The same guy www.windfreaktech.com has other generator models which do provide enough power to avoid the pre-amp, but they cost (way) more and are heavier. Note that I need a generator with EEPROM so it could fire at pre-programmed freq at power-up as I do not have an intelligent controller on the test platform to program it on the fly. You do, so can likely use any other synthesizer, even the one from that pseudo-VNA unit.BTW what is the bandwidth and loaded Q if you measure 3dB up from the max rtn loss dB point, instead of 3dB down from the reference level.
Roger's Force equation works from unloaded Q, being twice the loaded Q, measured 3dB up from the max rtn loss dB point on a S11 VNA scan. This is how you measure power bandwidth as the max power xfer level becomes 0dB and you measure the point where the power xfer is 3dB down from the peak power xfer dB level.
Not trying to trigger an argument here. Just stating how Roger's Force equation works and what Q measurement technique it is based on.
That "Q" value (calculating UP from the _minimum_ of S11) would be around 10,000. It is what the scanner software calculates by default, but this value has very little sense, and so I didn't event include it in my screenshots. It is somewhat strange that this is what Roger is using... Think about it, assuming the minimum on S11 plot is say -20 dBm, this implies 99% of power goes into the cavity. Now take a +3 dBm up point, this will be S11 of -17 dBm, that is 98% of power going into the cavity. So moving from -20 dBm to -17 dBm of S11 changes the amount of power in the cavity by... 1%.
Apparently even the "3 dBm down" method is rather gross for S11 measurements, and they usually recommend calculating Q factor from complex S11 values (via Smith chart or otherwise). But since I don't have a vector NA... no complex S11 values for me.Good luck with your tests.
Phil
Thank you, I will need it
-
#1419 by rfmwguy on 07 Jan, 2016 19:18
-
Now, if you're into more theory (than I am right now) here are 2 January 2016 Annals of Physics papers that MAY have a relationship with emdrive theory:
Perturbative vacuum wavefunctional for gauge theories in the Milne space:
http://www.sciencedirect.com/science/article/pii/S0003491615003851
Reformulations of Yang–Mills theories with space–time tensor fields: http://www.sciencedirect.com/science/article/pii/S0003491615004145
Actually, the 2nd one was mentioned in the Russian Emdrive forum, surprisingly.
.
