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#900
by
SeeShells
on 30 Dec, 2015 02:39
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Still getting my systems back up, hours of work still to go but TT and rfmwguy wanted to see my blown
Uhhh, methinks you need to finish that sentence shell.... 
I would like to see a picture of her blown antenna ...
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#901
by
Tellmeagain
on 30 Dec, 2015 02:52
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#902
by
graybeardsyseng
on 30 Dec, 2015 02:57
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Still getting my systems back up, hours of work still to go but TT and rfmwguy wanted to see my blown
Uhhh, methinks you need to finish that sentence shell....
I would like to see a picture of her blown antenna ...
WOW - No more magic smoke in that one. 
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#903
by
TheTraveller
on 30 Dec, 2015 03:27
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Still getting my systems back up, hours of work still to go but TT and rfmwguy wanted to see my blown
Uhhh, methinks you need to finish that sentence shell....
I would like to see a picture of her blown antenna ...
To each their own I suppose...
Actually, I asked her for it as well. Did see the mag to N transition pic...center conductor was matchstick as she described. One of the frustum antennas gave way and that imbalance wrecked the source transition.
this complexity is why I put the mag on the frustum. This type of power and balance is verrrry tricky...she's a great engineer and will solve it tho...
This damage highlights why a circulator, with Rf dummy load for the reflected Rf, is important. Protects the Rf generator from load impedance changes that can torch components.
As I see it now, working with a Maggie requires either the maggie antenna is inside the frustum or if external, is protected by a circulator and dummy load.
If using a solid state Rf amp, maybe it can handle massive load impedance, VSWR, changes or not. Need to design high VSWR protection based on amp specs.
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#904
by
rfmwguy
on 30 Dec, 2015 03:29
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Shell said her modified inverter supply is kickin'...think she has dialed up the diy efforts in just that alone. Now to make all the downline stuff more robust...got to love it.
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#905
by
VAXHeadroom
on 30 Dec, 2015 03:42
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*hides eyes in shame*
I'm so embarrassed - I made SUCH a rookie error in rendering the videos I've been doing.
In order to make the development go faster I only output every 10th row and column...and then forgot I had done it. I've only been showing 1% of the data! It really looks like the attached, and will take overnight to render. I can't wait to see this in motion...
P.S. recalculated. At 2.5 min/frame and 560 frames it'll be done in about 23 hours...
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#906
by
TheTraveller
on 30 Dec, 2015 03:44
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Shell said her modified inverter supply is kickin'...think she has dialed up the diy efforts in just that alone. Now to make all the downline stuff more robust...got to love it.
Roger burnt out 2 magnetrons & melted a hole in a waveguide during his 2002 Experimental build.
If Shell arched the stub antenna in the side waveguide extensions, there may be a hole burnt in each of them.
Shell's pathway seems to be similar to Roger's pathway. She is minus 1 maggie, maybe a male & female N connector pair, maybe some coax, maybe a hole or 2 and 2 stub antenna so far.
I'm sure when Shell gets 2 digit mN thrust, it will all be worthwhile.
Go Shell, GO!
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#907
by
graybeardsyseng
on 30 Dec, 2015 04:04
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Seriously - TT you have a very valuable comment about circulator and/or dummy load. And generally the Solid State devices are much more sensitive than Hollow State . Unless the driver/amp has some sort of **FAST ACTING** VSWR rollback safety or ALC type control there can be exploding solid state bits everywhere quite fast. That's why there were a lot of burned out finals on solid state radios when we transitioned from "valves".
Herm
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#908
by
aero
on 30 Dec, 2015 04:14
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@VAXHeadroom - Can you do anything with these csv files? I don't know what to suggest, just that two of the data sets are ~ 1 microsecond long. That is 2048 cycles, 64 times longer that the typical 32 cycle runs.
Each data set contains the final 14 time slices of the run, at 0.1 cycle intervals for all field and view angle, except the z slices of which there are 3, one inside the big end, (small slice number) one at z slice 30 and one at the inside the small end, (big slice number). If you may be able to work with this data and need information, PM me.
aero
...
@Dr. Rodal,
https://drive.google.com/folderview?id=0B1XizxEfB23tRm41bVFtM1pVYlU&usp=sharing
Are you finished with this data set containing 14 sets of csv files for 7 increasingly longer runs, ending with a 1 microsecond run? Runs are for the Yang-Shell 6 degree cavity model with antenna at the big end and at the small end for each run length. That is the same model that you have already post processed data for. If you are finished, or have otherwise secured the data, I would like to remove it so as to recover the Google drive space occupied by the folder. It is a significant percentage of the 15 GB of space available.
Note that the shorter run data sets should be duplicates of data that you have already post processed.
aero
I don't know whether I'm going to get the time to analyze again these data or other Meep data (if my memory is correct there is a very long run, much longer than others, that you had run that I have not had the time to analyze).
You have to be your own judge of what to keep and what to delete. The particular runs that I analyzed (for stress, force and Poynting vector field vs time) may be useful to others that may want to independently calculate stresses, forces and Poynting vector fields vs. time, and if you delete them, they may not be able to do such independent verification.
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#909
by
RFPlumber
on 30 Dec, 2015 05:33
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Seriously - TT you have a very valuable comment about circulator and/or dummy load. And generally the Solid State devices are much more sensitive than Hollow State . Unless the driver/amp has some sort of **FAST ACTING** VSWR rollback safety or ALC type control there can be exploding solid state bits everywhere quite fast. That's why there were a lot of burned out finals on solid state radios when we transitioned from "valves".
Herm
Btw, the above-mentioned 30W amp from ebay comes with a built-in 125W isolator. A very handy protection.
EDIT
Folks tinkering with magnetrons may want to add an off-the-shelf circulator / isolator into their design to avoid accidentally hitting the magnetron with 100% reflected power... Obviously both the circulator and the dummy load on the circulator (the one which makes an isolator out of it) will need to have the corresponding power rating (that of the magnetron).
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#910
by
Mulletron
on 30 Dec, 2015 09:37
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I just wanted to share some of the research I dug up while studying. It might be useful to someone. I feel this paper in particular is significant:
http://arxiv.org/abs/1006.5754The author's claim:
Most calculations of gravitomagnetic near-field (i.e. excluding gravitational radiation)
effects in linearized gravity have assumed steady mass currents. For example, the Lense-
Thirring [6] dragging of inertial frames can be thought of as the effect of a steady gravito-
magnetic field (for a simple derivation, see [7]).
Experimental consequences of Faraday-law (the first expression in equation 2) effects
have been considered in perturbations of orbits [8] and effects of a massive rotating object
rotating moving near a torsional oscillator[9].
Remarkably, however, the simple transcription of an electrical transformer[3] into a grav-
itational one does not seem to have been mentioned explicitly in the literature, so I claim:
There is a gravitational analog of an electrical transformer with the time-varying electrical
currents through wire windings replaced by mass-energy currents through suitable conduits.
Such a transformer can be used to step up or step down the “gravitomotive force” G (the
line integral of ~E defined above by analogy with electromotive force).
Also I believe to be significant:
http://arxiv.org/abs/0906.1281Both of the above provide solutions for time varying fields!
Other interesting information:
http://arxiv.org/abs/1206.0413http://arxiv.org/abs/1504.01763www.chem.utoronto.ca/~lpachon/ppapers/ClassQuantumGrav.23.2395.pdfwww.phys.uconn.edu/~mallett/Mallett2000.pdf (this is the time machine guy)
From Mallett:
The gravitational field of a noncirculating beam of light was studied many years ago by Tolman w1x. This was done by using the weak field approximation to Einstein’s gravitational field equations. Tolman then
determined the acceleration of a stationary particle in the neighborhood of the light beam. He found that
the acceleration experienced by the particle was twice as great as that expected on the basis of Newtonian theory for the gravitational field of a massive rod of similar length and density. This would seem to imply that, in some ways, light may be even more effective
than matter in generating a gravitational field.
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#911
by
SeeShells
on 30 Dec, 2015 10:27
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Seriously - TT you have a very valuable comment about circulator and/or dummy load. And generally the Solid State devices are much more sensitive than Hollow State . Unless the driver/amp has some sort of **FAST ACTING** VSWR rollback safety or ALC type control there can be exploding solid state bits everywhere quite fast. That's why there were a lot of burned out finals on solid state radios when we transitioned from "valves".
Herm
Btw, the above-mentioned 30W amp from ebay comes with a built-in 125W isolator. A very handy protection.
EDIT
Folks tinkering with magnetrons may want to add an off-the-shelf circulator / isolator into their design to avoid accidentally hitting the magnetron with 100% reflected power... Obviously both the circulator and the dummy load on the circulator (the one which makes an isolator out of it) will need to have the corresponding power rating (that of the magnetron).
No doubt it SS amps will need an load circulator or a dump for anything reflected back, that's standard microwave waveguide design. The new SS have gotten much better but still are not as robust and forgiving as the old tubes and a magnetron is a tube. That said, I thought I could get away without one in this first design and save some costs.
I still wonder why my antennas fried. I'm wondering if it wasn't not only the VSWR but the collapsing energy of stored energy in a high Q system? That would explain Shawyer's fried system tests and mine as well. aero had calculated Q's with perfect conductors in the astronomical ranges (we know that was not right) but with the correct Cu ~ 90k ( >120k with my silver platting). Also it has been reported the Panasonic Inverters if left to free wheel without a load can crank out to well over 6KV, that is some serious coronal discharges.
This may change in this next round of tests. I'm waiting for people to get off Christmas/New Years breaks to get some pricing on another way, a more stable way.
Shell
PS: On other news I'm slowly getting back my data into the new system.
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#912
by
MathewOrman
on 30 Dec, 2015 10:32
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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.
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#913
by
Flyby
on 30 Dec, 2015 10:36
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A question...
Both Yang and Shawyer (in his EMdrive2.0) use a microwave coupling window in their design.
I can find some nice texts/illustrations (fe Alesini papers) on all the different aspects and applications of couplers, but non is very clear to why their use in this specific case of the EMdrive makes sense?
To make sure I understand this correctly:
Is a coupler window used to dampen and equalize the EM power output from the magnetron so that a more steady microwave intensity is fed into the resonance cavity ?
And what effect do those adjusting screws have?
(Yang has them in her drawings, and I think I can spot them on Shawyer's rotating rig too)
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#914
by
TheTraveller
on 30 Dec, 2015 10:51
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No doubt it SS amps will need an load circulator or a dump for anything reflected back, that's standard microwave waveguide design. The new SS have gotten much better but still are not as robust and forgiving as the old tubes and a magnetron is a tube. That said, I thought I could get away without one in this first design and save some costs.
I still wonder why my antennas fried. I'm wondering if it wasn't not only the VSWR but the collapsing energy of stored energy in a high Q system? That would explain Shawyer's fried system tests and mine as well. aero had calculated Q's with perfect conductors in the astronomical ranges (we know that was not right) but with the correct Cu ~ 90k ( >120k with my silver platting). Also it has been reported the Panasonic Inverters if left to free wheel without a load can crank out to well over 6KV, that is some serious coronal discharges.
This may change in this next round of tests. I'm waiting for people to get off Christmas/New Years breaks to get some pricing on another way, a more stable way.
Shell
PS: On other news I'm slowly getting back my data into the new system.
When you say dump do you mean a rapid reduction in stored cavity energy?
As I understand it, if the Rf source is not feeding the cavity energy, the cavity energy can feed back to the Rf source. Like powering up a coil and then open circuiting it. Very large back EMF can develop as the coil is now open circuit.
The cavity will follow Qu / (2 Pi Freq) as to discharge TC. However if you stopped the Rf feed and shorted the antenna, the cavity losses per cycle would jump and discharge TC would drop. Sort of like charging a high voltage cap for many seconds and then shorting it.
So it may be possible to quickly dump the stored cavity energy into a shorted Rf feed. Would probably release heaps of magic smoke and maybe make a few holes for good measure.
IF YOU ARE NOT QUALIFIED, MESSING WITH THIS STUFF CAN KILL YOU!!
HIGH Q CAVITIES AMPLIFY THE INPUTTED RF ENERGY UPTO 100,000 TIMES. ALWAYS TREAT YOUR CAVITY LIKE A LETHAL HIGH VOLTAGE CAPACITOR. THEY ARE NOT THAT DIFFERENT.
Phil
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#915
by
TheTraveller
on 30 Dec, 2015 10:55
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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.
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#916
by
SeeShells
on 30 Dec, 2015 11:00
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No doubt it SS amps will need an load circulator or a dump for anything reflected back, that's standard microwave waveguide design. The new SS have gotten much better but still are not as robust and forgiving as the old tubes and a magnetron is a tube. That said, I thought I could get away without one in this first design and save some costs.
I still wonder why my antennas fried. I'm wondering if it wasn't not only the VSWR but the collapsing energy of stored energy in a high Q system? That would explain Shawyer's fried system tests and mine as well. aero had calculated Q's with perfect conductors in the astronomical ranges (we know that was not right) but with the correct Cu ~ 90k ( >120k with my silver platting). Also it has been reported the Panasonic Inverters if left to free wheel without a load can crank out to well over 6KV, that is some serious coronal discharges.
This may change in this next round of tests. I'm waiting for people to get off Christmas/New Years breaks to get some pricing on another way, a more stable way.
Shell
PS: On other news I'm slowly getting back my data into the new system.
When you say dump do you mean a rapid reduction in stored cavity energy?
As I understand it, if the Rf source is not feeding the cavity energy, the cavity energy can feed back to the Rf source. Like powering up a coil and then open circuiting it. Very large back EMF can develop as the coil is now open circuit.
The cavity will follow Qu / (2 Pi Freq) as to discharge TC. However if you stopped the Rf feed and shorted the antenna, the cavity losses per cycle would jump and discharge TC would drop. Sort of like charging a high voltage cap for many seconds and then shorting it.
So it may be possible to quickly dump the stored cavity energy into a shorted Rf feed. Would probably release heaps of magic smoke and maybe make a few holes for good measure.
IF YOU ARE NOT QUALIFIED, MESSING WITH THIS STUFF CAN KILL YOU!!
HIGH Q CAVITIES AMPLIFY THE INPUTTED RF ENERGY UPTO 100,000 TIMES. ALWAYS TREAT YOUR CAVITY LIKE A LETHAL HIGH VOLTAGE CAPACITOR. THEY ARE NOT THAT DIFFERENT.
Phil
This is true for even modest 100w systems Phil, even with a Q in the 10k range that is a lot of power.
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#917
by
TheTraveller
on 30 Dec, 2015 11:01
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A question...
Both Yang and Shawyer (in his EMdrive2.0) use a microwave coupling window in their design.
I can find some nice texts/illustrations (fe Alesini papers) on all the different aspects and applications of couplers, but non is very clear to why their use in this specific case of the EMdrivemakes sense?
To make sure I understand this correctly:
Is a coupler window used to dampen and equalize the EM power output from the magnetron so that a more steady microwave intensity is fed into the resonance cavity ?
And what effect do those adjusting screws have?
(Yang has them in her drawings, and I think I can spot them on Shawyer's rotating rig too)
The adjusting screws allow the VSWR seen by the Rf gen to be adjusted as low as possible.
The slot also effects VSWR and acts to decouple the 2 sections of the wave guide.
Later designs put the slot into the side wall, so the cavity is highly decoupled from the wave guide feed. See attachment.
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#918
by
TheTraveller
on 30 Dec, 2015 11:06
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This is true for even modest 100w systems Phil, even with a Q in the 10k range that is a lot of power.
Trust me I know, 100Ws and a 88k Qu cavity is to be respected. There will be quite a lot of magic smoke in that cavity and I don't want it to get out of control.
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#919
by
Flyby
on 30 Dec, 2015 11:26
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The adjusting screws allow the VSWR seen by the Rf gen to be adjusted as low as possible.
The slot also effects VSWR and acts to decouple the 2 sections of the wave guide.
Later designs put the slot into the side wall, so the cavity is highly decoupled from the wave guide feed. See attachment.
TT, I did notice all that.. but my Question is WHY ? why do you use a coupling window?
To start with, I suppose it isn't for aesthetic reasons ...
euh... VSWR... I'm not an engineer, but might that be "Voltage Standing Wave Ratio" ?
The parameter VSWR is a measure that numerically describes how well the antenna is impedance matched to the radio or transmission line it is connected to.
added:
nevermind on the VSWR. Found a good explanation :
https://www.maximintegrated.com/en/glossary/definitions.mvp/term/VSWR/gpk/815
