Quote from: WarpTech on 05/12/2015 02:16 pmFrom the thermal and A/m plots from EW, most of the resonance is happening at the big end. I would not put the magnetron in that space because the input there will probably perturb the waves. Shawyer put the input near the small end. I would put it "at" the small end, depending on wave polarization. The walls should do most of the reflecting, not the small end.Todd D.Please take a gander at this Demo Drive by Shawyer: http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=36313.0;attach=829850It seems to have the feed near the big diameter end.
From the thermal and A/m plots from EW, most of the resonance is happening at the big end. I would not put the magnetron in that space because the input there will probably perturb the waves. Shawyer put the input near the small end. I would put it "at" the small end, depending on wave polarization. The walls should do most of the reflecting, not the small end.Todd D.
Quote from: Rodal on 05/12/2015 07:25 pmQuote from: WarpTech on 05/12/2015 02:16 pmFrom the thermal and A/m plots from EW, most of the resonance is happening at the big end. I would not put the magnetron in that space because the input there will probably perturb the waves. Shawyer put the input near the small end. I would put it "at" the small end, depending on wave polarization. The walls should do most of the reflecting, not the small end.Todd D.Please take a gander at this Demo Drive by Shawyer: http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=36313.0;attach=829850It seems to have the feed near the big diameter end.Good call doctor. I find the stub coupler/feed at the larger diameter of the cavity interesting...thinking this was the end with the highest return loss/standing wave at 2.4 GHz...perhaps not. The stepper motor appears to be adjusting the length of a tuning stub centered in the cavity on the narrow end, probably something like this: http://i.stack.imgur.com/Vfdxq.png Its and old tried and true methodology.Regardless, this tuning stub is simply a matching element which can be fixed (non-adjustable) once a center frequency is set and a tuning stub length measurement can be made. Normally, this tuning stub is adjusted for best S parameter match/bandwidth: http://www.antenna-theory.com/definitions/sparameters.php
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Back a ways there existed in woo land something called a "Slepian Drive". Same guy?https://groups.yahoo.com/neo/groups/Stardrive1/conversations/topics/3910
Quote from: rfmwguy on 05/12/2015 07:48 pmQuote from: Rodal on 05/12/2015 07:25 pmQuote from: WarpTech on 05/12/2015 02:16 pmFrom the thermal and A/m plots from EW, most of the resonance is happening at the big end. I would not put the magnetron in that space because the input there will probably perturb the waves. Shawyer put the input near the small end. I would put it "at" the small end, depending on wave polarization. The walls should do most of the reflecting, not the small end.Todd D.Please take a gander at this Demo Drive by Shawyer: http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=36313.0;attach=829850It seems to have the feed near the big diameter end.Good call doctor. I find the stub coupler/feed at the larger diameter of the cavity interesting...thinking this was the end with the highest return loss/standing wave at 2.4 GHz...perhaps not. The stepper motor appears to be adjusting the length of a tuning stub centered in the cavity on the narrow end, probably something like this: http://i.stack.imgur.com/Vfdxq.png Its and old tried and true methodology.Regardless, this tuning stub is simply a matching element which can be fixed (non-adjustable) once a center frequency is set and a tuning stub length measurement can be made. Normally, this tuning stub is adjusted for best S parameter match/bandwidth: http://www.antenna-theory.com/definitions/sparameters.phpThank you. I agree with you
Early on in this thread, there was a lot of discussion of potential spaceflight applications which could be enabled by emdrives if the tech were to be viable. Here is an opportunity to roll some of that discussion into the design of the "challenge criteria" for an XPRIZE.http://forum.nasaspaceflight.com/index.php?topic=37563.0http://www.xprize.org/about/what-is-an-xprize
There's still the issue of drifting off tune with temperature
QUESTION 1: What is responsible for the huge time delay in Shaywer's force signal traces? For NASA Eagleworks this delay represents about ~4*10^9 electromagnetic wave cycles. For Shawyer this represents ~33*10^9 cycles. Clearly, this huge number of cycles has nothing to do with the Quantum Vacuum, or the speed of light, or the time required for a resonant cavity to reach steady state in standing waves. Is this time delay (20 sec) due to a time delay associated with a Q-multiplier effect ? Is the time delay mainly due to the phase shift settling with time ? (due to Shawyer working with a Q multiplier setup having a Q=X times multiplier with feedback, having a phase shift narrow in frequency). (hat tip to @Notsosureofit for the explanatory hint, any misinterpretation of which is mine).QUESTION 2: What is responsible for the time delay in Shaywer's force signal traces after the power is turned off? Note: quotes used to call attention to this message in case they have quotes linked to e-mail message forum notifications.Reference: http://www.emdrive.com/IAC-08-C4-4-7.pdf
Quote from: Mulletron on 05/12/2015 09:17 pmEarly on in this thread, there was a lot of discussion of potential spaceflight applications which could be enabled by emdrives if the tech were to be viable. Here is an opportunity to roll some of that discussion into the design of the "challenge criteria" for an XPRIZE.http://forum.nasaspaceflight.com/index.php?topic=37563.0http://www.xprize.org/about/what-is-an-xprizeI don't think you can begin to design any sort of mission until you know the equation of motion in free space.
Quote from: Rodal on 05/12/2015 07:59 pmQuote from: rfmwguy on 05/12/2015 07:48 pmQuote from: Rodal on 05/12/2015 07:25 pmQuote from: WarpTech on 05/12/2015 02:16 pmFrom the thermal and A/m plots from EW, most of the resonance is happening at the big end. I would not put the magnetron in that space because the input there will probably perturb the waves. Shawyer put the input near the small end. I would put it "at" the small end, depending on wave polarization. The walls should do most of the reflecting, not the small end.Todd D.Please take a gander at this Demo Drive by Shawyer: http://forum.nasaspaceflight.com/index.php?action=dlattach;topic=36313.0;attach=829850It seems to have the feed near the big diameter end.Good call doctor. I find the stub coupler/feed at the larger diameter of the cavity interesting...thinking this was the end with the highest return loss/standing wave at 2.4 GHz...perhaps not. The stepper motor appears to be adjusting the length of a tuning stub centered in the cavity on the narrow end, probably something like this: http://i.stack.imgur.com/Vfdxq.png Its and old tried and true methodology.Regardless, this tuning stub is simply a matching element which can be fixed (non-adjustable) once a center frequency is set and a tuning stub length measurement can be made. Normally, this tuning stub is adjusted for best S parameter match/bandwidth: http://www.antenna-theory.com/definitions/sparameters.phpThank you. I agree with you If that stub extends inside the frustum, that would explain why he put the input at the big end. I still say, it should be at the small end to avoid perturbing the harmonics.Todd
Quote from: deltaMass on 05/12/2015 09:04 pmThere's still the issue of drifting off tune with temperature... and acceleration. That is why I believe now that it should be pulsed, not steady state operation.Todd
Quote from: WarpTech on 05/12/2015 09:39 pmQuote from: deltaMass on 05/12/2015 09:04 pmThere's still the issue of drifting off tune with temperature... and acceleration. That is why I believe now that it should be pulsed, not steady state operation.ToddThat also makes sense to me. Separately, but interestingly the Serrano field effect device tested by Dr. White displayed the highest thrust/InputPower of any device, yet it only showed very short time impulses (like Dirac Delta Functions) instead of steady state operation (although to me its principle of operation is very different from the EM Drive, Dr. White classified this device also as a Q-thuster).