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#3220
by
zellerium
on 27 Feb, 2016 06:29
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A little like this?
Shell
Added: What are your dims?
top radius: 1.4 in
bottom radius: 4.4 in
height (between top and bottom planes): 8.2 in
top spherical radius: 4.07 in
bottom spherical radius: 12.81 in
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#3221
by
SeeShells
on 27 Feb, 2016 06:52
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A little like this?
Shell
Added: What are your dims?
top radius: 1.4 in
bottom radius: 4.4 in
height (between top and bottom planes): 8.2 in
top spherical radius: 4.07 in
bottom spherical radius: 12.81 in
Thanks for answering. Interesting dims.
What frequency are you planning to excite at? Are you looking for a TE mode?
Shell
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#3222
by
rfmwguy
on 27 Feb, 2016 14:14
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Speaking for myself - I want to wish Phil Wilson (TT) a speedy recovery as he now enters a critical phase of his treatment. His boundless enthusiasm for the emdrive, while perhaps a bother to others, has spirited me through some tough times during my build and testing.
We continue to correspond almost daily about emdrive rumors, developments, possibilities and sometimes just life in general. To my Aussie friend, I wish you the best of luck. Onwards and outwards. Keep in touch.
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#3223
by
SeeShells
on 27 Feb, 2016 15:18
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Speaking for myself - I want to wish Phil Wilson (TT) a speedy recovery as he now enters a critical phase of his treatment. His boundless enthusiasm for the emdrive, while perhaps a bother to others, has spirited me through some tough times during my build and testing.
We continue to correspond almost daily about emdrive rumors, developments, possibilities and sometimes just life in general. To my Aussie friend, I will you the best of luck. Onwards and outwards. Keep in touch.
Well said Dave. I second that.
Get Better Phil and Make it So.
Shell
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#3224
by
zellerium
on 27 Feb, 2016 15:41
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A little like this?
Shell
Added: What are your dims?
top radius: 1.4 in
bottom radius: 4.4 in
height (between top and bottom planes): 8.2 in
top spherical radius: 4.07 in
bottom spherical radius: 12.81 in
Thanks for answering. Interesting dims.
What frequency are you planning to excite at? Are you looking for a TE mode?
Shell
No problem!
Its resonant frequency is 2.46005 GHz.
I had been trying to excite a TE013, but I like the manufacturability of a smaller frustum. Cutting it from a single slug of aluminum will be much more accurate, and a thicker frustum should have less thermal warping.
After all, who knows if a TE013 will thrust better than a TE113? Maybe the theoretical quality of the former is slightly higher...
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#3225
by
SeeShells
on 27 Feb, 2016 16:39
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A little like this?
Shell
Added: What are your dims?
top radius: 1.4 in
bottom radius: 4.4 in
height (between top and bottom planes): 8.2 in
top spherical radius: 4.07 in
bottom spherical radius: 12.81 in
Thanks for answering. Interesting dims.
What frequency are you planning to excite at? Are you looking for a TE mode?
Shell
No problem!
Its resonant frequency is 2.46005 GHz.
I had been trying to excite a TE013, but I like the manufacturability of a smaller frustum. Cutting it from a single slug of aluminum will be much more accurate, and a thicker frustum should have less thermal warping.
After all, who knows if a TE013 will thrust better than a TE113? Maybe the theoretical quality of the former is slightly higher...
It is a beautiful asymmetrical mode I'll give you that.
As far as potential thrust, I simply don't know. Maybe Dr. Rodal has some input here, you know he is a little sharp on this stuff.
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#3226
by
Monomorphic
on 27 Feb, 2016 22:04
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FEKO lets you calculate the modes for different frequencies. It's a request option called Characteristic Modes. On the first test run, I calculated 6 modes for 3Ghz.
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#3227
by
SeeShells
on 28 Feb, 2016 00:25
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FEKO lets you calculate the modes for different frequencies. It's a request option called Characteristic Modes. On the first test run, I calculated 6 modes for 3Ghz.
Six different resonate frequencies for a selected frequency window?
Shell
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#3228
by
spupeng7
on 28 Feb, 2016 00:30
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Ernst Mach was one of Einstein's inspirations, what he said about conservation could be worth review. Not that I have got around to it myself yet
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#3229
by
spupeng7
on 28 Feb, 2016 01:04
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THE OMG moment still fills my thoughts as what I heard was like a 2kg mass dropping several cms inside the small end down frustum (very solid THUD).
That sounds like an extraordinary result. I sincerely hope you can replicate it (and capture it on video - seriously guys, why aren't we recording every experiment on film, just in case? Recording and storage is practically free)!
Yes, an excellent addition to the testing routine...
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#3230
by
spupeng7
on 28 Feb, 2016 01:11
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Been reading a lot of ideas and theories in T1-T6 and would like to pose a question for discussion or future consideration.
Assuming the emdrive is an open system and continues to demonstrate observational results, it may be well beyond the capabilites of any research laboratory to directly measure whatever it might be interacting with outside its confines.
Just wanted to posit this in the minds of some of the theoretical braintrusts here. Not being a theoretical type, not sure where indirect measurements fit into the big scheme of things regarding acceptance in the scientific community.
Right with you there Guy, to us Machians it is the rest of the universe that the emdrive could be gaining a purchase against. The vague possibility does exist however, that we may one day use inertial mass to measure the mass of the observable universe...
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#3231
by
X_RaY
on 28 Feb, 2016 08:06
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FEKO lets you calculate the modes for different frequencies. It's a request option called Characteristic Modes. On the first test run, I calculated 6 modes for 3Ghz.
While looking to your last pics, I have a strong assumption that two flanking mode shapes are only one in real!
Are these resonant frequencies pretty close to each other? I know this phenomena from my work with the EMPro
Eigenmode solver. The program calculate these mode shapes 2 times pendicular to each other because of it solves the problem with port excitation 0° and 90°, consequently there exists two slightly different solutions because of the non symmetrical tetrahedral mesh. The field pattern of the two single frequencies looks identical but rotated by 90°. (In your FEKO pics it seems to be a 45° rotation difference around the central z axis). The calculated resonant frequencies are paired/related and have differences of typical a few MHz due to the mesh size*.
Maybe FEKO use a similar calculation method for Eigenmode requests.
Therefore I think we see three different physically modes only.
*Note that rotation invariant shapes like TE01p are not paired in this sense. There is only a single frequency related to such modes shapes (at least in EMPro).
*Note also this double modes phenomenon was no longer present after the
FEM Solver was used with a specific antenna and coaxial antenna feed.
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#3232
by
Monomorphic
on 28 Feb, 2016 13:25
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Therefore I think we see three different physically modes only.
This is correct. I didn't notice it at first, but it is obvious when scrolling through the modes. Each mode is rotated along the central axis what looks like 90 or 45 degrees. Good catch!
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#3233
by
SeeShells
on 28 Feb, 2016 15:44
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Therefore I think we see three different physically modes only.
This is correct. I didn't notice it at first, but it is obvious when scrolling through the modes. Each mode is rotated along the central axis what looks like 90 or 45 degrees. Good catch!
What is the bandwidth of the RF source?
Shell
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#3234
by
X_RaY
on 28 Feb, 2016 16:22
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Therefore I think we see three different physically modes only.
This is correct. I didn't notice it at first, but it is obvious when scrolling through the modes. Each mode is rotated along the central axis what looks like 90 or 45 degrees. Good catch!
What is the bandwidth of the RF source?
Shell
Eigen Resonance calculations are not related to any RF source. Resonance conditions depends on geometry and material properties of the cavity.
For visualisation the displayed amplitudes are simply scaled i.e. relative to "1" and its only used to find the mode dependent resonant frequency of a system in an inverse way. Therefore the resonant frequency is an absolut value, no BW needed.
In EMPro the Q will also be displayed using the Eigenmode solver.The calculated Q depends on material properties, dimensions and frequency at resonance.
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#3235
by
SeeShells
on 28 Feb, 2016 16:53
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Therefore I think we see three different physically modes only.
This is correct. I didn't notice it at first, but it is obvious when scrolling through the modes. Each mode is rotated along the central axis what looks like 90 or 45 degrees. Good catch!
What is the bandwidth of the RF source?
Shell
Eigen Resonance calculations are not related to any RF source. Resonance conditions depends on geometry and material properties of the cavity.
For visualisation the displayed amplitudes are simply scaled i.e. relative to "1" and its only used to find the mode dependent resonant frequency of a system in an inverse way. Therefore the resonant frequency is an absolut value, no BW needed.
In EMPro the Q will also be displayed using the Eigenmode solver.The calculated Q depends on material properties, dimensions and frequency.
Ok, now this makes sense, I've been trying to figure out what you did. Thanks.
Shell
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#3236
by
X_RaY
on 28 Feb, 2016 17:14
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Therefore I think we see three different physically modes only.
This is correct. I didn't notice it at first, but it is obvious when scrolling through the modes. Each mode is rotated along the central axis what looks like 90 or 45 degrees. Good catch!
What is the bandwidth of the RF source?
Shell
Eigen Resonance calculations are not related to any RF source. Resonance conditions depends on geometry and material properties of the cavity.
For visualisation the displayed amplitudes are simply scaled i.e. relative to "1" and its only used to find the mode dependent resonant frequency of a system in an inverse way. Therefore the resonant frequency is an absolut value, no BW needed.
In EMPro the Q will also be displayed using the Eigenmode solver.The calculated Q depends on material properties, dimensions and frequency.
Ok, now this makes sense, I've been trying to figure out what you did. Thanks.
Shell
It's a fast way to get an idea of the mode frequency in a given cavity,much faster than calculation of the scattering matrices over frequency using FEM or other techniques.
FEKO uses different methods (see pic below).
I am not sure how to add a noise signal or defined BW to the source in FEKO.
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#3237
by
X_RaY
on 28 Feb, 2016 20:32
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OK, we are able to calculate resonant frequencies in any conical cavity using grid based simulation methodes as well as exact solutions and approximative spreadsheets. Thats good news I think.
But all of this is basic microwave engineering stuff and at the end of the day it tells us nothing about the possibilities of thrust generation at all since it is based on standard formula which predicts no thrust using a simple resonator with any shape.
This brings us back to energie and momentum conservation and more complex experimental theory. Lets start there to get some answer. A short review of arxiv alone tells me its hard to get an overview of all the theories and nobody is able to understand or even read all of this. A huge amount of physically papers are available on the internet beside of some great ideas published in this forum like Dr. notsosureofitīs hypothesis and many other.
The best chance to get answers is the collective work of all users of the forum!
We need more reliable experimental results as well as new theories to explain what happens in the frustums which seems to generate thrust!
Therefore
all new ideas of any lurker is needed and very welcome.
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#3238
by
SeeShells
on 28 Feb, 2016 21:25
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#3239
by
ThinkerX
on 28 Feb, 2016 22:21
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OK, we are able to calculate resonant frequencies in any conical cavity using grid based simulation methodes as well as exact solutions and approximative spreadsheets. Thats good news I think.
But all of this is basic microwave engineering stuff and at the end of the day it tells us nothing about the possibilities of thrust generation at all since it is based on standard formula which predicts no thrust using a simple resonator with any shape.
This brings us back to energie and momentum conservation and more complex experimental theory. Lets start there to get some answer. A short review of arxiv alone tells me its hard to get an overview of all the theories and nobody is able to understand or even read all of this. A huge amount of physically papers are available on the internet beside of some great ideas published in this forum like Dr. notsosureofitīs hypothesis and many other.
The best chance to get answers is the collective work of all users of the forum!
We need more reliable experimental results as well as new theories to explain what happens in the frustums which seems to generate thrust!
Therefore all new ideas of any lurker is needed and very welcome.
Theories are simply that and there are a dozzen out there. Maybe trolling those who have reported something and the modes, frequencies will provide better insights.
Since you asked...
Not really a theory. More like half an idea, though it is one I believe Shell and possibly Traveler will be in a position to test. (Maybe Rfmwguy as well.)
Conduct tests with the frustum's interior at different pressures - very low pressure, 'normal' pressure, and high pressure. I suspect the amount of 'thrust' will vary accordingly. And no leaks. And no, it's not a thermal effect I suspect either, though there may be a sort of thermal 'brake.'
