Author Topic: EM Drive Developments - related to space flight applications - Thread 5  (Read 761700 times)

Offline TheTraveller

Of course resonances can exist in a tapered cavity that have lower frequencies than the size of the smallest end. The energy would just exist within the largest part effectively shortening the cavity. Greg even shows this in a plot.

This is similar to how partially loaded cavities work, which is a common way to back out permitivitty of materials.

If the EM wave can't reach the end plate, as the diameter is well below cutoff, how will the EM wave be able of efficiently propogate to bounce off an end plate it can't reach?

Or do you ignore Roger's advise to ALWAYS operate the small end ABOVE cutoff?

The small end of the cavity is 8.8mm in dia, the big end is 35.2mm in dia and the end plate separation is 75mm.  You really believe that cavity will resonate at 4.1GHz despite the small end cutoff being 40GHz and the big end cutoff being 10GHz.

Even disallowing that both ends are claimed to be happily operating WELL below cutoff, to achieve resonance some whole number of 1/2 waves at the effective overall guide wavelength need to fit between the end plates.

There is no way what can happen.

His resonance model is rubbish.
« Last Edit: 10/29/2015 10:59 AM 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 cl33250

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To detect rotation just add cameras to the top and side of the cubesat. We can watch the stars move and use that to calculate the speed of rotation. Small accelerometers are also available.

Would need a standard cubesat 3 axis mag torquer to obtain stability before firing up the EMDrives. My youngest son was involved in a multi uni project to design a 2U cubesat. He worked on the command and control system which was in 1 cube that supported additional experiments in the other cube. I got a really good idea how to put a cubesat together and how to control it's orientation.
If it ever comes to this, for simplicity, why not put reflectors on the cubesat and track rotation externally from the ground/ISS.  This simplifies the design and lowers weight--it really doesn't matter whether the satellite is stabilized-accelerations can be tracked externally.  No need to worry about worry about failed control systems/reaction wheels/accelerometers/cameras.

Online meberbs

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The most respected labs that have performed this experiment have yielded almost no thrust.

Who are these "Most Respected Labs"? Where is there data, frustum dimensions, excitation modes, VNA resonance freq scans. Force measurement rig designs? I know of no failed EMDrive tests. Such data needs to be analysed as building and testing an EMDrive is not like baking a simple cake recipe. Get one step wrong and there will be no thrust.

So PLEASE SHARE the null data. We might just be able to work out where they went wrong and prevent other builders from making the same mistake.

The only labs I know of that are reasonably respected are Eagleworks, which had very small thrust measurements, enough that that recent paper about the Lorentz force errors actually is significant on that scale. Combined with other potential error sources, their experiment isn't a solid confirmation of the emdrive.

Tajmar is the only other respected scientist I know of working on this. I believve his paper explicitly said that it could neither confirm nor deny the thrust as a real effect.

I am not saying there is no effect, but there isn't a confirmation either way. Unless you know of a respected lab that has measured thrust large enough to be free of any chance of experimental error. I think that would come up more often if there was one, but I could have missed it.

Of course resonances can exist in a tapered cavity that have lower frequencies than the size of the smallest end. The energy would just exist within the largest part effectively shortening the cavity. Greg even shows this in a plot.

This is similar to how partially loaded cavities work, which is a common way to back out permitivitty of materials.

If the EM wave can't reach the end plate, as the diameter is well below cutoff, how will the EM wave be able of efficiently propogate to bounce off an end plate it can't reach?

Or do you ignore Roger's advise to ALWAYS operate the small end ABOVE cutoff?

The small end of the cavity is 8.8mm in dia, the big end is 35.2mm in dia and the end plate separation is 75mm.  You really believe that cavity will resonate at 4.1GHz despite the small end cutoff being 40GHz and the big end cutoff being 10GHz.

Even disallowing that both ends are claimed to be happily operating WELL below cutoff, to achieve resonance some whole number of 1/2 waves at the effective overall guide wavelength need to fit between the end plates.

There is no way what can happen.

His resonance model is rubbish.

According to your logic, no resonances could exist at all in a cone shaped cavity. That is an incorrect claim, easily testable by experiment. If you really think a cone couldn't have resonances, and want to run that experiment, I should be able to modify Greg's results easily enough for a cone shape. Also if you give me a specific case of one of the emdrives that you have designed before with spherical ends, I can rerun his equations for that case so you can see the results.

Please don't try to use intuition to argue against math. Electromagnetism is weird and non-intuitive. If you think there is anything wrong with any of the equations on that page, please point out exactly where you think the math goes wrong.

Offline Notsosureofit

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It would appear Egan used c in decameters/sec rather than cm/sec in his frequency calculation.

Very quick check so please verify.

Second look, still quick, so maybe c is ok.  Wavenumbers are reasonable ? but the frequencies don't make sense.  I'll have to find some time to look deeper. (didn't Rodal look at this some time ago ?)
« Last Edit: 10/29/2015 01:39 PM by Notsosureofit »

Online meberbs

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It would appear Egan used c in decameters/sec rather than cm/sec in his frequency calculation.

Very quick check so please verify.

Good question.

ω = k*c and f = ω / (2*pi) 

For the first TM mode:

f =  0.861947 cm^-1 * 3e10 cm/s / (2*pi) = 4.11549377 gigahertz

The units are all OK. (ω is a frequency in radians per second instead of cycles per second, which he uses in the equations to reduce how many factors of 2*pi are floating around.)

Offline zellerium

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My next questions would be:
How long would it take to create an obvious rotation with 5 W injected into dual opposing frustums? (and what rotation could be deemed proof of concept?)
Can a 5 W Ka band transmitter and two smaller frustums fit on a 6u Cubesat with all other necessary components?
Will the transmitter have the frequency range necessary to power the frustum at the temperature extremes?

Assuming an unloaded Q of 50,000, Df of 0.9 and spherical end plates, 5Ws should generate around 1.5mNs per frustum. Can't share the Rf gen as each frustum will need independent freq tracking. For 2 frustums this project will need 2 duplicate Rf gens and freq tracking.

Thanks for the calculation. I was assuming the frustums would have a waveguide in between and share the same resonant frequency, but on second thought I agree, the frustums could not be identical enough to have identical resonance with a Q that high.

I suppose you could still induce a significant rotation if you had only one frustum away from the cg.

Months ago, maybe in topic-thread 3, the idea of Cubesat was discussed and someone explained that instabilities/unknown environment on these small orbits are too big - quick calculations returned perturbations nearly on scale of N/Kw. Adding the inability to control directly environment or make any changes once the satelite is launched.

I don't agree. You can model the drag in LEO quite well, it'll be on the order of mN (for a CubeSat) but you would just need to prove your frustum is spinning you in direction that drag wouldn't be able to do. As TT mentioned, you can compensate for perturbations with reaction wheels and magnetorquers to desaturate.

Offline zellerium

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According to your logic, no resonances could exist at all in a cone shaped cavity. That is an incorrect claim, easily testable by experiment. ...

I think you missed the key work efficiently in TT's post. Yes of course you can get any shape to resonate, but to resonate with high quality and low losses we want to minimize the evanescent decay. When wave bounces off an opening because its wavelength is too large to fit, some energy will still propagate into the opening and decay exponentially.
I believe what he and Shawyer are getting at is we should have each side of the resonator be above the cutoff, not that we have to. 
« Last Edit: 10/29/2015 02:52 PM by zellerium »

Offline Devilstower

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The small size of the cubesats is why I'm creating a frustum that is made from a series of nesting rings think collapsible camping cup. 

However, I wasn't able to find a microwave source that, based on TT's spreadsheet, would give me the resonance I wanted at a scale that fit a "cheap" cubesat, so I'm building with the usual magnetron and at a size similar to most DIY runs. I'm just considering this a x2 scale of the final design.

Mostly, I'm just concentrating on not boiling my eyeballs. I'm a writer and geologist. My usual engineering limits involve slicing up plywood to make small boats. I think the last time I soldered something, it was a kit from, Tandy.
« Last Edit: 10/29/2015 03:15 PM by Devilstower »

Offline glennfish

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The small size of the cubesats is why I'm creating a frustrum that is made from a series of nesting rings think collapsible camping cup. 

However, I wasn't able to find a microwave source that, based on TT's spreadsheet, would give me the resonance I wanted at a scale that fit a "cheap" cubesat, so I'm building with the usual magnetron and at a size similar to most DIY runs. I'm just considering this a x2 scale of the final design.

Mostly, I'm just concentrating on not boiling my eyeballs. I'm a writer and geologist. My usual engineering limits involve slicing up plywood to make small boats. I think the last time I soldered something, it was a kit from, Tandy.

ah heck, granted the fractional megabuck required for the cubesat stuff, plus the free launch, why not leave out the microwave source and just transmit from an earth location.  See if you can talk someone in NORAD into doing a radar lock while the cubesat is over the horizon.  Better still, see if NORAD will tell you their transmitter frequency in advance so you can design your frustum.  :)

Offline rfmwguy

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According to your logic, no resonances could exist at all in a cone shaped cavity. That is an incorrect claim, easily testable by experiment. ...

I think you missed the key work efficiently in TT's post. Yes of course you can get any shape to resonate, but to resonate with high quality and low losses we want to minimize the evanescent decay. When wave bounces off an opening because its wavelength is too large to fit, some energy will still propagate into the opening and decay exponentially.
I believe what he and Shawyer are getting at is we should have each side of the resonator be above the cutoff, not that we have to.
Cavity resonance is typically measured using S21 and/or S11. Center freqs are a good general indicator on S21, but higher power cavities need the S11 to make sure the most power is in the can as opposed to reflecting back towards the source.

Its a bit of application issue where resonance occurs and how important it is IMHO. If its a receive filter, return loss or S11 is far less important that S21 through line measurements. Where the 3dB points usually are are all thats needed to find the center. Wacky rf engineers like myself want to tune for minumum insertion loss for receiver applications and to heck with return loss or 3dB points.  With receiver noise floors, including preamps, any fractional dB improvement is golden. Yes, I'm a receiver geek, meds have not fixed that yet  8)

Offline rfmwguy

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The small size of the cubesats is why I'm creating a frustrum that is made from a series of nesting rings think collapsible camping cup. 

However, I wasn't able to find a microwave source that, based on TT's spreadsheet, would give me the resonance I wanted at a scale that fit a "cheap" cubesat, so I'm building with the usual magnetron and at a size similar to most DIY runs. I'm just considering this a x2 scale of the final design.

Mostly, I'm just concentrating on not boiling my eyeballs. I'm a writer and geologist. My usual engineering limits involve slicing up plywood to make small boats. I think the last time I soldered something, it was a kit from, Tandy.

ah heck, granted the fractional megabuck required for the cubesat stuff, plus the free launch, why not leave out the microwave source and just transmit from an earth location.  See if you can talk someone in NORAD into doing a radar lock while the cubesat is over the horizon.  Better still, see if NORAD will tell you their transmitter frequency in advance so you can design your frustum.  :)
Wow, thats a long run of coax or waveguide  ::)

Offline rfcavity

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Of course resonances can exist in a tapered cavity that have lower frequencies than the size of the smallest end. The energy would just exist within the largest part effectively shortening the cavity. Greg even shows this in a plot.

This is similar to how partially loaded cavities work, which is a common way to back out permitivitty of materials.

If the EM wave can't reach the end plate, as the diameter is well below cutoff, how will the EM wave be able of efficiently propogate to bounce off an end plate it can't reach?

Or do you ignore Roger's advise to ALWAYS operate the small end ABOVE cutoff?

The small end of the cavity is 8.8mm in dia, the big end is 35.2mm in dia and the end plate separation is 75mm.  You really believe that cavity will resonate at 4.1GHz despite the small end cutoff being 40GHz and the big end cutoff being 10GHz.

Even disallowing that both ends are claimed to be happily operating WELL below cutoff, to achieve resonance some whole number of 1/2 waves at the effective overall guide wavelength need to fit between the end plates.

There is no way what can happen.

His resonance model is rubbish.

Waves don't bounce in a cavity. It's a resonance that has math different from physical bouncing. Bouncing is a way to explain to people without math, but the analogy does not hold 100% and is not perfect.

By the way, the method you use to calculate cut off uses cut offs derived from cylinder cavities. In textbooks, these cutoff equations are derived exactly the same way as Greg derives for the tapered cavity. So if he is wrong, by rule, you are also wrong.

However, checking his work, he is right. I trained in EM. Rodal also says he is right. Please, show what part of his work is wrong, instead of writing paragraphs.

Offline rfmwguy

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Of course resonances can exist in a tapered cavity that have lower frequencies than the size of the smallest end. The energy would just exist within the largest part effectively shortening the cavity. Greg even shows this in a plot.

This is similar to how partially loaded cavities work, which is a common way to back out permitivitty of materials.

If the EM wave can't reach the end plate, as the diameter is well below cutoff, how will the EM wave be able of efficiently propogate to bounce off an end plate it can't reach?

Or do you ignore Roger's advise to ALWAYS operate the small end ABOVE cutoff?

The small end of the cavity is 8.8mm in dia, the big end is 35.2mm in dia and the end plate separation is 75mm.  You really believe that cavity will resonate at 4.1GHz despite the small end cutoff being 40GHz and the big end cutoff being 10GHz.

Even disallowing that both ends are claimed to be happily operating WELL below cutoff, to achieve resonance some whole number of 1/2 waves at the effective overall guide wavelength need to fit between the end plates.

There is no way what can happen.

His resonance model is rubbish.

Waves don't bounce in a cavity. It's a resonance that has math different from physical bouncing. Bouncing is a way to explain to people without math, but the analogy does not hold 100% and is not perfect.

By the way, the method you use to calculate cut off uses cut offs derived from cylinder cavities. In textbooks, these cutoff equations are derived exactly the same way as Greg derives for the tapered cavity. So if he is wrong, by rule, you are also wrong.

However, checking his work, he is right. I trained in EM. Rodal also says he is right. Please, show what part of his work is wrong, instead of writing paragraphs.

Please, show what part of his work is wrong - He never went beyond theory in his scientific method and gave up after the math exercise.

Offline X_RaY

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Of course resonances can exist in a tapered cavity that have lower frequencies than the size of the smallest end. The energy would just exist within the largest part effectively shortening the cavity. Greg even shows this in a plot.

This is similar to how partially loaded cavities work, which is a common way to back out permitivitty of materials.

If the EM wave can't reach the end plate, as the diameter is well below cutoff, how will the EM wave be able of efficiently propogate to bounce off an end plate it can't reach?

Or do you ignore Roger's advise to ALWAYS operate the small end ABOVE cutoff?

The small end of the cavity is 8.8mm in dia, the big end is 35.2mm in dia and the end plate separation is 75mm.  You really believe that cavity will resonate at 4.1GHz despite the small end cutoff being 40GHz and the big end cutoff being 10GHz.

Even disallowing that both ends are claimed to be happily operating WELL below cutoff, to achieve resonance some whole number of 1/2 waves at the effective overall guide wavelength need to fit between the end plates.

There is no way what can happen.

His resonance model is rubbish.

Waves don't bounce in a cavity. It's a resonance that has math different from physical bouncing. Bouncing is a way to explain to people without math, but the analogy does not hold 100% and is not perfect.

By the way, the method you use to calculate cut off uses cut offs derived from cylinder cavities. In textbooks, these cutoff equations are derived exactly the same way as Greg derives for the tapered cavity. So if he is wrong, by rule, you are also wrong.

However, checking his work, he is right. I trained in EM. Rodal also says he is right. Please, show what part of his work is wrong, instead of writing paragraphs.

Please, show what part of his work is wrong - He never went beyond theory in his scientific method and gave up after the math exercise.
The problem is most time this kind of math/formulas is right(leads to useful results). If the EM-Drive effect is real, the formulas have to be expanded to explain the known standard physics/results as well as the EM-Drive effect. Thats the basic problem we have since thread 1. :-\

EDIT: rfmwguy i saw your measurement videos and i am really trying to believe in this effect, but if its its real, however, it has to be calculable anyway, and it have to satisfy the description above.
« Last Edit: 10/29/2015 08:37 PM by X_RaY »

Offline rfcavity

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Of course resonances can exist in a tapered cavity that have lower frequencies than the size of the smallest end. The energy would just exist within the largest part effectively shortening the cavity. Greg even shows this in a plot.

This is similar to how partially loaded cavities work, which is a common way to back out permitivitty of materials.

If the EM wave can't reach the end plate, as the diameter is well below cutoff, how will the EM wave be able of efficiently propogate to bounce off an end plate it can't reach?

Or do you ignore Roger's advise to ALWAYS operate the small end ABOVE cutoff?

The small end of the cavity is 8.8mm in dia, the big end is 35.2mm in dia and the end plate separation is 75mm.  You really believe that cavity will resonate at 4.1GHz despite the small end cutoff being 40GHz and the big end cutoff being 10GHz.

Even disallowing that both ends are claimed to be happily operating WELL below cutoff, to achieve resonance some whole number of 1/2 waves at the effective overall guide wavelength need to fit between the end plates.

There is no way what can happen.

His resonance model is rubbish.

Waves don't bounce in a cavity. It's a resonance that has math different from physical bouncing. Bouncing is a way to explain to people without math, but the analogy does not hold 100% and is not perfect.

By the way, the method you use to calculate cut off uses cut offs derived from cylinder cavities. In textbooks, these cutoff equations are derived exactly the same way as Greg derives for the tapered cavity. So if he is wrong, by rule, you are also wrong.

However, checking his work, he is right. I trained in EM. Rodal also says he is right. Please, show what part of his work is wrong, instead of writing paragraphs.

Please, show what part of his work is wrong - He never went beyond theory in his scientific method and gave up after the math exercise.

Who, traveller? He,s trying to integrate by parts over different sized cylindrical cavities but that doesn't work as it totally ignores the boundary that exists in the decreasing direction which doesn't exist in a cylinder. That's one problem, but there are probably more. I'm on a phone in Cambridge and I'm catching a flight in the morning to Asia so I can't show the math right now but I can try later.

Offline rfmwguy

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Of course resonances can exist in a tapered cavity that have lower frequencies than the size of the smallest end. The energy would just exist within the largest part effectively shortening the cavity. Greg even shows this in a plot.

This is similar to how partially loaded cavities work, which is a common way to back out permitivitty of materials.

If the EM wave can't reach the end plate, as the diameter is well below cutoff, how will the EM wave be able of efficiently propogate to bounce off an end plate it can't reach?

Or do you ignore Roger's advise to ALWAYS operate the small end ABOVE cutoff?

The small end of the cavity is 8.8mm in dia, the big end is 35.2mm in dia and the end plate separation is 75mm.  You really believe that cavity will resonate at 4.1GHz despite the small end cutoff being 40GHz and the big end cutoff being 10GHz.

Even disallowing that both ends are claimed to be happily operating WELL below cutoff, to achieve resonance some whole number of 1/2 waves at the effective overall guide wavelength need to fit between the end plates.

There is no way what can happen.

His resonance model is rubbish.

Waves don't bounce in a cavity. It's a resonance that has math different from physical bouncing. Bouncing is a way to explain to people without math, but the analogy does not hold 100% and is not perfect.

By the way, the method you use to calculate cut off uses cut offs derived from cylinder cavities. In textbooks, these cutoff equations are derived exactly the same way as Greg derives for the tapered cavity. So if he is wrong, by rule, you are also wrong.

However, checking his work, he is right. I trained in EM. Rodal also says he is right. Please, show what part of his work is wrong, instead of writing paragraphs.

Please, show what part of his work is wrong - He never went beyond theory in his scientific method and gave up after the math exercise.

Who, traveller? He,s trying to integrate by parts over different sized cylindrical cavities but that doesn't work as it totally ignores the boundary that exists in the decreasing direction which doesn't exist in a cylinder. That's one problem, but there are probably more. I'm on a phone in Cambridge and I'm catching a flight in the morning to Asia so I can't show the math right now but I can try later.
Safe travels...fly Cathay Pacific whenever you get the chance ;)

Offline SeeShells

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Of course resonances can exist in a tapered cavity that have lower frequencies than the size of the smallest end. The energy would just exist within the largest part effectively shortening the cavity. Greg even shows this in a plot.

This is similar to how partially loaded cavities work, which is a common way to back out permitivitty of materials.

If the EM wave can't reach the end plate, as the diameter is well below cutoff, how will the EM wave be able of efficiently propogate to bounce off an end plate it can't reach?

Or do you ignore Roger's advise to ALWAYS operate the small end ABOVE cutoff?

The small end of the cavity is 8.8mm in dia, the big end is 35.2mm in dia and the end plate separation is 75mm.  You really believe that cavity will resonate at 4.1GHz despite the small end cutoff being 40GHz and the big end cutoff being 10GHz.

Even disallowing that both ends are claimed to be happily operating WELL below cutoff, to achieve resonance some whole number of 1/2 waves at the effective overall guide wavelength need to fit between the end plates.

There is no way what can happen.

His resonance model is rubbish.

Waves don't bounce in a cavity. It's a resonance that has math different from physical bouncing. Bouncing is a way to explain to people without math, but the analogy does not hold 100% and is not perfect.

By the way, the method you use to calculate cut off uses cut offs derived from cylinder cavities. In textbooks, these cutoff equations are derived exactly the same way as Greg derives for the tapered cavity. So if he is wrong, by rule, you are also wrong.

However, checking his work, he is right. I trained in EM. Rodal also says he is right. Please, show what part of his work is wrong, instead of writing paragraphs.

Please, show what part of his work is wrong - He never went beyond theory in his scientific method and gave up after the math exercise.
In for a second then out again.... busy.

Aero and I were working on an extended frustum for the Yang-Shell 6o model. Remember that one? To throw this out there into the pot to speak here is an meep run of that cavity. While not perfect it does show some structure even when it's obvious there is little "bounce" as you call it from the endplates, the cavity still can resonate and even thought he Q is lower it still shows a ok Q.

Shell

Now back to work...

Added remember we are dealing with a 3D cavity that can resonate in all directions X Y and Z the sidewalls reflect as well as the endplates.
« Last Edit: 10/29/2015 08:40 PM by SeeShells »

Offline rfmwguy

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Of course resonances can exist in a tapered cavity that have lower frequencies than the size of the smallest end. The energy would just exist within the largest part effectively shortening the cavity. Greg even shows this in a plot.

This is similar to how partially loaded cavities work, which is a common way to back out permitivitty of materials.

If the EM wave can't reach the end plate, as the diameter is well below cutoff, how will the EM wave be able of efficiently propogate to bounce off an end plate it can't reach?

Or do you ignore Roger's advise to ALWAYS operate the small end ABOVE cutoff?

The small end of the cavity is 8.8mm in dia, the big end is 35.2mm in dia and the end plate separation is 75mm.  You really believe that cavity will resonate at 4.1GHz despite the small end cutoff being 40GHz and the big end cutoff being 10GHz.

Even disallowing that both ends are claimed to be happily operating WELL below cutoff, to achieve resonance some whole number of 1/2 waves at the effective overall guide wavelength need to fit between the end plates.

There is no way what can happen.

His resonance model is rubbish.

Waves don't bounce in a cavity. It's a resonance that has math different from physical bouncing. Bouncing is a way to explain to people without math, but the analogy does not hold 100% and is not perfect.

By the way, the method you use to calculate cut off uses cut offs derived from cylinder cavities. In textbooks, these cutoff equations are derived exactly the same way as Greg derives for the tapered cavity. So if he is wrong, by rule, you are also wrong.

However, checking his work, he is right. I trained in EM. Rodal also says he is right. Please, show what part of his work is wrong, instead of writing paragraphs.

Please, show what part of his work is wrong - He never went beyond theory in his scientific method and gave up after the math exercise.
The problem is most time this kind of math/formulas is right(leads to useful results). If the EM-Drive effect is real, the formulas have to be expanded to explain the known standard physics/results as well as the EM-Drive effect. Thats the basic problem we have since thread 1. :-\
Think thats why I temporarily gave up on the theory end of things as nothing I read or already knew made any sense when trying to apply it to emdrive. So to avoid brain tilt, thought I would build one and see. Now thats done and I might get more dramatic results in Phase II (if that happens) I might stick my toe back into the theory world. I'll then try again to look for anything that references kinetic energy and electromagnetic radiation. Seem to recall I drew a big fat zero as no one, including me, would have ever thought to look for it.

One avenue I wanted to explore someday is geosyncronous sats. The ones that transmit downlinks at fairly high power. What is their station-keepin needs, etc.

Offline X_RaY

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Of course resonances can exist in a tapered cavity that have lower frequencies than the size of the smallest end. The energy would just exist within the largest part effectively shortening the cavity. Greg even shows this in a plot.

This is similar to how partially loaded cavities work, which is a common way to back out permitivitty of materials.

If the EM wave can't reach the end plate, as the diameter is well below cutoff, how will the EM wave be able of efficiently propogate to bounce off an end plate it can't reach?

Or do you ignore Roger's advise to ALWAYS operate the small end ABOVE cutoff?

The small end of the cavity is 8.8mm in dia, the big end is 35.2mm in dia and the end plate separation is 75mm.  You really believe that cavity will resonate at 4.1GHz despite the small end cutoff being 40GHz and the big end cutoff being 10GHz.

Even disallowing that both ends are claimed to be happily operating WELL below cutoff, to achieve resonance some whole number of 1/2 waves at the effective overall guide wavelength need to fit between the end plates.

There is no way what can happen.

His resonance model is rubbish.

Waves don't bounce in a cavity. It's a resonance that has math different from physical bouncing. Bouncing is a way to explain to people without math, but the analogy does not hold 100% and is not perfect.

By the way, the method you use to calculate cut off uses cut offs derived from cylinder cavities. In textbooks, these cutoff equations are derived exactly the same way as Greg derives for the tapered cavity. So if he is wrong, by rule, you are also wrong.

However, checking his work, he is right. I trained in EM. Rodal also says he is right. Please, show what part of his work is wrong, instead of writing paragraphs.

Please, show what part of his work is wrong - He never went beyond theory in his scientific method and gave up after the math exercise.
The problem is most time this kind of math/formulas is right(leads to useful results). If the EM-Drive effect is real, the formulas have to be expanded to explain the known standard physics/results as well as the EM-Drive effect. Thats the basic problem we have since thread 1. :-\
Think thats why I temporarily gave up on the theory end of things as nothing I read or already knew made any sense when trying to apply it to emdrive. So to avoid brain tilt, thought I would build one and see. Now thats done and I might get more dramatic results in Phase II (if that happens) I might stick my toe back into the theory world. I'll then try again to look for anything that references kinetic energy and electromagnetic radiation. Seem to recall I drew a big fat zero as no one, including me, would have ever thought to look for it.

One avenue I wanted to explore someday is geosyncronous sats. The ones that transmit downlinks at fairly high power. What is their station-keepin needs, etc.
Please dont give up, i am looking forward to your (and SheShell's) next results!
I hope sometimes we can explain this effect with the math(More conclusive than the present tries.).
That's possibly the way to the stars. :)
« Last Edit: 10/29/2015 09:16 PM by X_RaY »

Offline rfmwguy

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