Author Topic: EM Drive Developments - related to space flight applications - Thread 3  (Read 1839141 times)

Offline TheTraveller

I asked Martin Tajmar directly by email about cavity dimensions that would be off by a factor 2, and he replied confirming the numbers were indeed internal radii instead of diameters.

He added he already uploaded a revised manuscript altogether with some other typo corrections and some additional clarifications at the AIAA website, but revisions from the conference will appear only after 21st of August.

For now, the updated paper is online on the UD-Dresden website.

In the updated paper the height is still confirmed to be 68.6 mm:
Quote from: Martin Tajmar
Our final tapered cavity design had an internal top radius of 38.5 mm, a bottom radius of 54.1 mm and a height of 68.6 mm

So:
- internal big diameter = 0.1082 m
- internal small diameter = 0.077 m
- height = 0.00686 m

To @Rodal, @TheTraveller and others: can you try to find resonances and modes with your COMSOL and spreadsheets programs with those dimensions?

No resonance found using those revised numbers.
http://forum.nasaspaceflight.com/index.php?topic=37642.msg1410218#msg1410218 ;)

The length/height I used was twice what was quoted. The cavity at 68.6mm  is way too short to resonant at 2.45GHz.

I suggest Tajmar needs some help that knows what they are doing.
"As for me, I am tormented with an everlasting itch for things remote. I love to sail forbidden seas.”
Herman Melville, Moby Dick

Offline TheTraveller

Think of it as horsepower in the cavity world. The bigger the better, right? Over the top pronouncements get attention. When anyone claims super high Qs, its all relative to they test methodology they are using in the real world.

I thought we had settled how Q was measured.

To be very clear, the Chinese, EW, Shawyer and myself are taking unloaded 1 port S11 -3db off the peak return loss dB bandwidths. That is the way the Q is measured for these cavities. It may not be how you would measure the loaded Q but it is the way Q is measured in EMDrives. Shawyers Force equation uses S11 1 port return loss dB driven unloaded Q.

Attached is an example of a 1 port S11 return loss Q measurement Paul March posted on NSF. The cavity did not have a dielectric. Clearly Qs of 50k are possible with a plain hand made copper frustum with flat end plates. Curve the end plates and the Q will go higher. Machine the cavity to 0.05mm accuracy and the Q will go higher. Highly polish all the interior surfaces and the Q will go higher.
"Unloaded" is relative, the port (for S11) measurement have already a 50 Ohm impedance, its design to be almost free of reflections... ???
But i don't know if there's a better way to discover the Q, actually no i think

german file with explanations how to do
http://www-elsa.physik.uni-bonn.de/Lehrveranstaltungen/FP-E106/E106-Erlaeuterungen.pdf

The defacto way to measure unloaded Q in the EMDrive world is via 1 port S11 -3db off the peak return loss dBs.

Like it or not, it is the way the measurement is done.
"As for me, I am tormented with an everlasting itch for things remote. I love to sail forbidden seas.”
Herman Melville, Moby Dick

Offline X_RaY

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Think of it as horsepower in the cavity world. The bigger the better, right? Over the top pronouncements get attention. When anyone claims super high Qs, its all relative to they test methodology they are using in the real world.

I thought we had settled how Q was measured.

To be very clear, the Chinese, EW, Shawyer and myself are taking unloaded 1 port S11 -3db off the peak return loss dB bandwidths. That is the way the Q is measured for these cavities. It may not be how you would measure the loaded Q but it is the way Q is measured in EMDrives. Shawyers Force equation uses S11 1 port return loss dB driven unloaded Q.

Attached is an example of a 1 port S11 return loss Q measurement Paul March posted on NSF. The cavity did not have a dielectric. Clearly Qs of 50k are possible with a plain hand made copper frustum with flat end plates. Curve the end plates and the Q will go higher. Machine the cavity to 0.05mm accuracy and the Q will go higher. Highly polish all the interior surfaces and the Q will go higher.
"Unloaded" is relative, the port (for S11) measurement have already a 50 Ohm impedance, its design to be almost free of reflections... ???
But i don't know if there's a better way to discover the Q, actually no i think

german file with explanations how to do
http://www-elsa.physik.uni-bonn.de/Lehrveranstaltungen/FP-E106/E106-Erlaeuterungen.pdf

The defacto way to measure unloaded Q in the EMDrive world is via 1 port S11 -3db off the peak return loss dBs.

Like it or not, it is the way the measurement is done.
I am with you at this point :)
like i've said
"But i don't know if there's a better way to discover the Q, actually no i think "
« Last Edit: 07/31/2015 05:37 PM by X_RaY »

Offline X_RaY

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I asked Martin Tajmar directly by email about cavity dimensions that would be off by a factor 2, and he replied confirming the numbers were indeed internal radii instead of diameters.

He added he already uploaded a revised manuscript altogether with some other typo corrections and some additional clarifications at the AIAA website, but revisions from the conference will appear only after 21st of August.

For now, the updated paper is online on the UD-Dresden website.

In the updated paper the height is still confirmed to be 68.6 mm:
Quote from: Martin Tajmar
Our final tapered cavity design had an internal top radius of 38.5 mm, a bottom radius of 54.1 mm and a height of 68.6 mm

So:
- internal big diameter = 0.1082 m
- internal small diameter = 0.077 m
- height = 0.00686 m

To @Rodal, @TheTraveller and others: can you try to find resonances and modes with your COMSOL and spreadsheets programs with those dimensions?

No resonance found using those revised numbers.
http://forum.nasaspaceflight.com/index.php?topic=37642.msg1410218#msg1410218 ;)

The length/height I used was twice what was quoted. The cavity at 68.6mm  is way too short to resonant at 2.45GHz.

I suggest Tajmar needs some help that knows what they are doing.
to make it short, Yes ;D
he could ask us
« Last Edit: 07/31/2015 05:42 PM by X_RaY »

Offline TheTraveller

I am with you at this point :)
like i've said
"But i don't know if there's a better way to discover the Q, actually no i think "

Prof Yang has an equation to calc unloaded Q but I have never been able to get it working. It is in the 2010 paper attached.

Quote
The quality factor of this resonator under no load can be calculated by the following equation:

Qu=∫|H|2dv/h/2∫|nxH|2ds+tgd∫|H|2dv = (14)

Where tg is the electric loss within the cavity, n is the normal vector of the wall, s is the cavity surface area, v is the volume of the cavity.

If anyone else can get it to work, please share how you worked it out.
« Last Edit: 07/31/2015 05:43 PM by TheTraveller »
"As for me, I am tormented with an everlasting itch for things remote. I love to sail forbidden seas.”
Herman Melville, Moby Dick

Offline X_RaY

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I am with you at this point :)
like i've said
"But i don't know if there's a better way to discover the Q, actually no i think "

Prof Yang has an equation to calc unloaded Q but I have never been able to get it working. It is in the 2010 paper attached.

Quote
The quality factor of this resonator under no load can be calculated by the following equation:

Qu=∫|H|2dv/h/2∫|nxH|2ds+tgd∫|H|2dv = (14)

Where tg is the electric loss within the cavity, n is the normal vector of the wall, s is the cavity surface area, v is the volume of the cavity.

If anyone else can get it to work, please share how you worked it out.
what is "tgd"? :o
couldn't find a definition in the paper
« Last Edit: 07/31/2015 05:51 PM by X_RaY »

Offline TheTraveller

I am with you at this point :)
like i've said
"But i don't know if there's a better way to discover the Q, actually no i think "

Prof Yang has an equation to calc unloaded Q but I have never been able to get it working. It is in the 2010 paper attached.

Quote
The quality factor of this resonator under no load can be calculated by the following equation:

Qu=∫|H|2dv/h/2∫|nxH|2ds+tgd∫|H|2dv = (14)

Where tg is the electric loss within the cavity, n is the normal vector of the wall, s is the cavity surface area, v is the volume of the cavity.

If anyone else can get it to work, please share how you worked it out.
what is "tgd"? :o
couldn't find a definition in the paper
tg is defined. Equation attached.

Would be really good to get this working as then we can see the Q change as the length and end plate diameters change. So can tune the cavity dimensions for both high Df and high Q. Magic.
"As for me, I am tormented with an everlasting itch for things remote. I love to sail forbidden seas.”
Herman Melville, Moby Dick

Offline Rodal

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I am with you at this point :)
like i've said
"But i don't know if there's a better way to discover the Q, actually no i think "

Prof Yang has an equation to calc unloaded Q but I have never been able to get it working. It is in the 2010 paper attached.

Quote
The quality factor of this resonator under no load can be calculated by the following equation:

Qu=∫|H|2dv/h/2∫|nxH|2ds+tgd∫|H|2dv = (14)

Where tg is the electric loss within the cavity, n is the normal vector of the wall, s is the cavity surface area, v is the volume of the cavity.

If anyone else can get it to work, please share how you worked it out.
what is "tgd"? :o
couldn't find a definition in the paper
tg is defined. Equation attached.

Would be really good to get this working as then we can see the Q change as the length and end plate diameters change. So can tune the cavity dimensions for both high Df and high Q. Magic.

The tg term (tg is the "electric loss within the cavity") is not included in the classic electromagnetic theory of resonant cavities since for standing waves the energy is such that when B is max, E is zero, and vice versa, the energy goes from B to E to B for standing waves. For standing waves all you need to consider is B and the surface losses (eddy currents) due to B.


The inclusion of the term tg is due to her implication that the fields inside the cavity are not standing waves.  She doesn't clarify why except to ask readers to consider ions inside the cavity. 

She NEVER gives an explicit equation for tg, she just gives the words "electric loss within the cavity"

And what is the "d" after tg ?  the other d's are differentials.   It cannot be a differential here otherwise it would negate the integral that follows it. Is that "d" a typo?



The term including tg doesn't make sense to me.   If tg is due to electric losses it should belong in the denominator, with the losses, it should not be added !

Which means that she is probably missing a parenthesis, and the tg term should be added to the denominator of the previous term:

Qu=∫(|H|^2) dv/(2 h∫(|nxH|^2) ds+tgd ∫(|H|^2) dv )

This was published in the Journal of her own University in Xibei "Journal of Northwestern Polytechnical University Vol 28 No 6 Dec 2010".  This journal has zero impact factor - an academic measure of quotations for peer reviewed journals-. Yes, zero, I am not exaggerating , see:  https://www.researchgate.net/journal/1000-2758_Xibei_Gongye_Daxue_Xuebao_Journal_of_Northwestern_Polytechnical_University 

Then this becomes the standard equation to calculate Q, the equation present in Wikipedia:



It is what I used to calculate Q as well.
« Last Edit: 07/31/2015 06:55 PM by Rodal »

Offline Devilstower

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The idea that someone might put their hand on Yang's device and "feel it push" put me in mind of a story from many years ago—the Dean Drive.

In the 1950s, well-known science fiction author and editor John W. Campbell claimed to have encountered a "reactionless drive" created by a man named Dean.

"In particular, Campbell said he had seen this thing sit on a bathroom scale; it weighed, say, nine pounds when it was at rest. When it was turned on -- by plugging in an ordinary quarter-inch electric drill that was incorporated into the gadget -- gears turned, weights whirled, and the scale indicated a weight of perhaps 8.5 pounds! This is an impressive thrust; if you could apply continuously that much thrust (1/18 g!) in free fall you would be able to colonize the solar system. The Dean Drive would be the key to space travel even if it never produced enough thrust to actually lift itself."

The device was later shown to aerospace engineer and author, G. Harry Stine, who swore he felt it push against his hand.

However, Dean was very secretive about his device. He purposely fudged diagrams given to others, even taking out patents that didn't resemble the device he demonstrated. After he died, the device was never found. I've read accounts from Campbell, Stine and Pournelle, and much of their experience with Dean comes to mind when I look at Shawyer.

But I often find myself remembering what Stine said. "I felt it push."

http://www.jerrypournelle.com/science/dean.html


Offline TheTraveller

The idea that someone might put their hand on Yang's device and "feel it push" put me in mind of a story from many years ago—the Dean Drive.

In the 1950s, well-known science fiction author and editor John W. Campbell claimed to have encountered a "reactionless drive" created by a man named Dean.

"In particular, Campbell said he had seen this thing sit on a bathroom scale; it weighed, say, nine pounds when it was at rest. When it was turned on -- by plugging in an ordinary quarter-inch electric drill that was incorporated into the gadget -- gears turned, weights whirled, and the scale indicated a weight of perhaps 8.5 pounds! This is an impressive thrust; if you could apply continuously that much thrust (1/18 g!) in free fall you would be able to colonize the solar system. The Dean Drive would be the key to space travel even if it never produced enough thrust to actually lift itself."

The device was later shown to aerospace engineer and author, G. Harry Stine, who swore he felt it push against his hand.

However, Dean was very secretive about his device. He purposely fudged diagrams given to others, even taking out patents that didn't resemble the device he demonstrated. After he died, the device was never found. I've read accounts from Campbell, Stine and Pournelle, and much of their experience with Dean comes to mind when I look at Shawyer.

But I often find myself remembering what Stine said. "I felt it push."

http://www.jerrypournelle.com/science/dean.html

Once saw a video of a Dean Drive machine hanging from chains from the apex of a tripod stand. It remained stationary as it pulled a load across the floor, toward itself. Think it was on a US tv show called the Dave Garroway Show? Have searched but never found the video. Yes I know how it works by stiction but that demo I saw was hard to explain by stiction as the mass it was drawing toward itself was much bigger than the Dean Drive machine.

BTW one of my goals with the EMDrive is to "Feel It Push" against my hand.
"As for me, I am tormented with an everlasting itch for things remote. I love to sail forbidden seas.”
Herman Melville, Moby Dick

Offline X_RaY

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I am with you at this point :)
like i've said
"But i don't know if there's a better way to discover the Q, actually no i think "

Prof Yang has an equation to calc unloaded Q but I have never been able to get it working. It is in the 2010 paper attached.

Quote
The quality factor of this resonator under no load can be calculated by the following equation:

Qu=∫|H|2dv/h/2∫|nxH|2ds+tgd∫|H|2dv = (14)

Where tg is the electric loss within the cavity, n is the normal vector of the wall, s is the cavity surface area, v is the volume of the cavity.

If anyone else can get it to work, please share how you worked it out.
what is "tgd"? :o
couldn't find a definition in the paper
tg is defined. Equation attached.

Would be really good to get this working as then we can see the Q change as the length and end plate diameters change. So can tune the cavity dimensions for both high Df and high Q. Magic.

The tg term (tg is the "electric loss within the cavity") is not included in the classic electromagnetic theory of resonant cavities since for standing waves the energy is such that when B is max, E is zero, and vice versa, the energy goes from B to E to B for standing waves. For standing waves all you need to consider is B and the surface losses (eddy currents) due to B.


The inclusion of the term tg is due to her implication that the fields inside the cavity are not standing waves.  She doesn't clarify why except to ask readers to consider ions inside the cavity. 

She NEVER gives an explicit equation for tg, she just gives the words "electric loss within the cavity"

And what is the "d" after tg ?  the other d's are differentials.   It cannot be a differential here otherwise it would negate the integral that follows it. Is that "d" a typo?



The term including tg doesn't make sense to me.   If tg is due to electric losses it should belong in the denominator, with the losses, it should not be added !

Which means that she is probably missing a parenthesis, and the tg term should be added to the denominator of the previous term:

Qu=∫(|H|^2) dv/(2 h∫(|nxH|^2) ds+tgd ∫(|H|^2) dv )

This shows a very sloppy paper and very poor "peer review"

Then this becomes the standard equation to calculate Q, the equation present in Wikipedia:



It is what I used to calculate Q as well.
May be the change of the tg if the dimensions are changed so not tgd but dtg?
Don't know if this make much more sense jet...
Would be the loss over the surface or volume integral
« Last Edit: 07/31/2015 06:55 PM by X_RaY »

Offline Rodal

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...
May be the change of the tg if the dimensions are changed so not tgd but dtg?
Don't know if this make much more sense jet...
Would be the loss over the surface or volume integral

No, the translation in the Roger Shawyer EM Drive page butchered this equation.

The equation shown by TheTraveller



 is incorrect: it is not Yang's equation


I attach the correct equation from the original in Chinese.

The tg term is additive to the denominator, as I thought. The "d" is not a d, it is a delta

In the Chinese paper she clearly states that h is the skin depth, so she clearly forgot to include the angular frequency omega in her equation - poor peer review -

In the Chinese paper she clearly states that tgDelta is the dielectric loss in the cavity. tgdelta means: tangent delta, the loss tangent of the dielectric material !!!  In the terrible translation not only they butchered the equation  but they incorrectly translated this as the electric losses within the cavity!!! it is the dielectric loss, NOT the electric loss.  This is very important, it is the first time I see a mention of dielectric in Yang's paper, implying that she used dielectrics, at least initially in 2010

Her equation in Chinese makes perfect sense !!!

Take a gander

it is the standard equation to calculate Q, the equation present in Wikipedia:



« Last Edit: 07/31/2015 08:12 PM by Rodal »

Offline rfmwguy

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Think of it as horsepower in the cavity world. The bigger the better, right? Over the top pronouncements get attention. When anyone claims super high Qs, its all relative to they test methodology they are using in the real world.

I thought we had settled how Q was measured.

To be very clear, the Chinese, EW, Shawyer and myself are taking unloaded 1 port S11 -3db off the peak return loss dB bandwidths. That is the way the Q is measured for these cavities. It may not be how you would measure the loaded Q but it is the way Q is measured in EMDrives. Shawyers Force equation uses S11 1 port return loss dB driven unloaded Q.

Attached is an example of a 1 port S11 return loss Q measurement Paul March posted on NSF. The cavity did not have a dielectric. Clearly Qs of 50k are possible with a plain hand made copper frustum with flat end plates. Curve the end plates and the Q will go higher. Machine the cavity to 0.05mm accuracy and the Q will go higher. Highly polish all the interior surfaces and the Q will go higher.
"Unloaded" is relative, the port (for S11) measurement have already a 50 Ohm impedance, its design to be almost free of reflections... ???
But i don't know if there's a better way to discover the Q, actually no i think

german file with explanations how to do
http://www-elsa.physik.uni-bonn.de/Lehrveranstaltungen/FP-E106/E106-Erlaeuterungen.pdf

The defacto way to measure unloaded Q in the EMDrive world is via 1 port S11 -3db off the peak return loss dBs.

Like it or not, it is the way the measurement is done.
Its an invented technique that any RF engineer will say is nonconformal. An EM drive is an RF device and should be tested with integrity as opposed to unconventional methodology. IOW this is specsmanship. In legitimate RF systems, Qs of 100K+ will be viewed as nonsensical to the engineering community.

Therefore, it is settled, Shawyer and Yang are likely using unconventional methodology to define Q and should consult with the British Standards Institute or other reputable body to resolve their specification claims.
« Last Edit: 07/31/2015 07:02 PM by rfmwguy »

Offline BusterSky

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 Stumbled upon some news about this sort of propulsion recently. Sounds revolutionary but is it serious ?
I have seen scores of BS articles claiming world changing discoveries over the past years and I would like to know if I can  follow this or if I have to put it in the trash can ( I am not an expert in the field ).

Offline birchoff

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Think of it as horsepower in the cavity world. The bigger the better, right? Over the top pronouncements get attention. When anyone claims super high Qs, its all relative to they test methodology they are using in the real world.

I thought we had settled how Q was measured.

To be very clear, the Chinese, EW, Shawyer and myself are taking unloaded 1 port S11 -3db off the peak return loss dB bandwidths. That is the way the Q is measured for these cavities. It may not be how you would measure the loaded Q but it is the way Q is measured in EMDrives. Shawyers Force equation uses S11 1 port return loss dB driven unloaded Q.

Attached is an example of a 1 port S11 return loss Q measurement Paul March posted on NSF. The cavity did not have a dielectric. Clearly Qs of 50k are possible with a plain hand made copper frustum with flat end plates. Curve the end plates and the Q will go higher. Machine the cavity to 0.05mm accuracy and the Q will go higher. Highly polish all the interior surfaces and the Q will go higher.
"Unloaded" is relative, the port (for S11) measurement have already a 50 Ohm impedance, its design to be almost free of reflections... ???
But i don't know if there's a better way to discover the Q, actually no i think

german file with explanations how to do
http://www-elsa.physik.uni-bonn.de/Lehrveranstaltungen/FP-E106/E106-Erlaeuterungen.pdf

The defacto way to measure unloaded Q in the EMDrive world is via 1 port S11 -3db off the peak return loss dBs.

Like it or not, it is the way the measurement is done.
Its an invented technique that any RF engineer will say is nonconformal. An EM drive is an RF device and should be tested with integrity as opposed to unconventional methodology. IOW this is specsmanship. In legitimate RF systems, Qs of 100K+ will be viewed as nonsensical to the engineering community.

Therefore, it is settled, Shawyer and Yang are likely using unconventional methodology to define Q and should consult with the British Standards Institute or other reputable body to resolve their specification claims.

Hmmm, If Shawyer and Yang are using non standard methodology to figure out Q. What does this non standard methodology tell us. For example is there a difference in result between the Shawyer methodology and the standard methodology? If so, with what parameters does the Q result begin to diverge? What is the implication of this divergence?

Also, and most interestingly. Why has Shawyer and Yang opted for this non standard methodology?
« Last Edit: 07/31/2015 07:07 PM by birchoff »

Offline TheTraveller

Think of it as horsepower in the cavity world. The bigger the better, right? Over the top pronouncements get attention. When anyone claims super high Qs, its all relative to they test methodology they are using in the real world.

I thought we had settled how Q was measured.

To be very clear, the Chinese, EW, Shawyer and myself are taking unloaded 1 port S11 -3db off the peak return loss dB bandwidths. That is the way the Q is measured for these cavities. It may not be how you would measure the loaded Q but it is the way Q is measured in EMDrives. Shawyers Force equation uses S11 1 port return loss dB driven unloaded Q.

Attached is an example of a 1 port S11 return loss Q measurement Paul March posted on NSF. The cavity did not have a dielectric. Clearly Qs of 50k are possible with a plain hand made copper frustum with flat end plates. Curve the end plates and the Q will go higher. Machine the cavity to 0.05mm accuracy and the Q will go higher. Highly polish all the interior surfaces and the Q will go higher.
"Unloaded" is relative, the port (for S11) measurement have already a 50 Ohm impedance, its design to be almost free of reflections... ???
But i don't know if there's a better way to discover the Q, actually no i think

german file with explanations how to do
http://www-elsa.physik.uni-bonn.de/Lehrveranstaltungen/FP-E106/E106-Erlaeuterungen.pdf

The defacto way to measure unloaded Q in the EMDrive world is via 1 port S11 -3db off the peak return loss dBs.

Like it or not, it is the way the measurement is done.
Its an invented technique that any RF engineer with say is nonconformal. An EM drive is an RF device and should be tested with integrity as opposed to unconventional methodology. IOW this is specsmanship. In legitimate RF systems, Qs of 100K+ will be viewed as nonsensical to the engineering community.

Therefore, it is settled, Shawyer and Yang are likely using unconventional methodology to define Q and should consult with the British Standards Institute or other reputable body to resolve their specification claims.

This is not a 2 port cavity. Normally there is only one hole in the cavity and the cavity is tested like it is an antenna. Probably because it only has 1 port / hole.

I didn't create the unloaded Q return loss measurement system. I just understand how the measurement is done to get the unloaded Q that Shawyer uses in his Force equation. Tajmar, Shawyer, EWs, Prof Yang and myself all use this method.

Also plan to freq track my 1 port cavity by measuring the reflected power versus forward power, which can be turned into VSWR and return loss. It may not be the conventional way but it will work.
"As for me, I am tormented with an everlasting itch for things remote. I love to sail forbidden seas.”
Herman Melville, Moby Dick

Offline CraigPichach

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More thoughts on getting an experiment that actually provides some useful information and order of magnitude above background.. do we really need to fire the magnetron for 120 seconds if we go to higher power? (i.e. if we get a pulsed magnetron at 1MW, fire it for mili-seconds at resonance (TM010)) we should see something; correct?). This ironically is easier to cool and implement than 100kW for 2 minutes.

Also is there any thought to modelling resonance with ANSYS HFFS vs. COMSOL? Anyone on here any good at ANSYS HFFS?

Offline Rodal

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More thoughts on getting an experiment that actually provides some useful information and order of magnitude above background.. do we really need to fire the magnetron for 120 seconds if we go to higher power? (i.e. if we get a pulsed magnetron at 1MW, fire it for mili-seconds at resonance (TM010)) we should see something; correct?). This ironically is easier to cool and implement than 100kW for 2 minutes.

Also is there any thought to modelling resonance with ANSYS HFFS vs. COMSOL? Anyone on here any good at ANSYS HFFS?

I am good with ANSYS.  Don't see the need to use ANSYS to model resonance when there is an exact solution available for resonance.

Offline CraigPichach

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Is there an exact solution for 915MHz though? Are you able to calculate dimensions for a copper frustrum?
« Last Edit: 07/31/2015 07:23 PM by CraigPichach »

Offline TheTraveller

Hmmm, If Shawyer and Yang are using non standard methodology to figure out Q. What does this non standard methodology tell us. For example is there a difference in result between the Shawyer methodology and the standard methodology? If so, with what parameters does the Q result begin to diverge? What is the implication of this divergence?

Also, and most interestingly. Why has Shawyer and Yang opted for this non standard methodology?

Doing S11 return loss measurements to determine unloaded Q on a 1 port resonant system is NOT non standard. This method is the standard way to measure EMDrive cavities unloaded Q. As used by EWs, Shawyer, Prof Yang, Tajmar and myself.

What others are talking about is doing 2 port loaded Q measurements using S21 methodology. No one in the EMDrive world is interested in loaded Q values or doing 2 port (2 holes in the cavity) S21 measurements.

Here is a paper describing how to do unloaded Q measurements using S11. It is not correct to say using S11 to measure unloaded Q on a 1 port cavity is non standard.

2 documents attached to support that opinion.
« Last Edit: 07/31/2015 07:36 PM by TheTraveller »
"As for me, I am tormented with an everlasting itch for things remote. I love to sail forbidden seas.”
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