The most likely explanation is that I have made an error in programming my spreadsheet somewhere. I originally thought the error related to a measuring error in one of the constants. Then I started getting redshift of 0.6 htz, that implies a fairly large measurement error somewhere. Since I'm pulling the photon rocket equations from published literature, the error has to be in how I'm calculating the redshift (possibly in the number of photons). Anyone know what I should be doing to get redshift as an integer?
Good morning. I have been lurking and observing various emdrive communities for quite a long time. Mostly, I wonder and read, hoping people will talk about what I'm wondering about. I tend not to ask questions because my ignorance of the subject matter is profound, but for the last few days, my curiosity has really been a source of frustration.What is the source of the resonance in the resonance cavity? Is the copper acting as a mirror for the microwaves, or is there some mechanism at work other than reflection?If it is acting as a mirror, then I have some questions about an unrelated set of experiments I read about some time ago. A group of researchers apparently made some kind of microwave mirror out of an "electrical short circuit", that they were able to vibrate over a nano-meter at 0.25c. Doing so coaxed virtual photons into becoming actual photons, through some theorized property of the Casimir effect. I do not fully understand what they mean by the vague term in quotes, but it seems curious regardless.Given that the vibrations they reported are 0.25c, does this mean the surface of their microwave mirror is not a physical surface but rather some kind of field?If the surface of their microwave mirror is not a physical surface, would it be possible to create a non-physical microwave mirror surface in an emdrive, and if so, would there be any worthwhile benefits to doing so such as greater control of resonance, a more flexible/dynamic shape, mitigation of thermal deformation, ruling out potential error sources, etc?In either case, if an emdrive's current copper frustum is acting as a microwave mirror, is it possible that resonance is somehow creating a similar nano-scale vibration at relativistic speeds, coaxing virtual particles into becoming real particles? If so, what would be the implications for thrust signals?I am a software developer and not a scientist or engineer, so I am fully aware that these questions are likely quite misguided. Still, I can only contain my curiosity for so long, and I figure there's little harm in wondering aloud once in a while. Thank you for all the great reading over the months.
I have not read any actual papers about it, just a series of articles reporting on it.You can find a lot of links here:https://www.google.com/search?q=mirror+virtual+photon+to+actual+photon
For light, one hertz is one plank constant.
That seems consistent with what I read, yes. :-)
Quote from: DanP on 10/02/2015 06:50 pmThat seems consistent with what I read, yes. :-)OK i am reading the paper...and i find the following:"If we consider the literal experiment of moving a physical mirror near the speed light,we quickly see that this experiment is not feasible. Braggio et al. considered[6] the case of moving a typical microwave mirror in an oscillating motion at a frequency of 2 GHz with a displacement of 1 nm. This produces a velocity ratio of onlyv/c~10^-7 with an expected photon production rate of approximately 1 per day. Nevertheless, it requires an input of mechanical power of 100 MW while, at the same time, the system would need to be cooled to ~20 mK to ensure that the EM feld is in its vacuum state...."The actual experiments (also in vacuum) work at room temperature.Nevertheless its a very interesting paper!
Quote from: SeeShells on 10/02/2015 11:38 amQuote from: R.W. Keyes on 10/01/2015 10:57 pmHi everyone, I've been away for a while, and I have tried to catch up but there's just so much to read.What is that general opinion about a high Q being necessary for the emdrive to work efficiently? I haven't seen much about going to the extremes of high-Q, such as superconducting cavities at cryogenic temperatures. I understand that such a cool temperature makes test conditions more difficult, but if high Q will result in greater efficiency, isn't this worth trying? Also, magnesium diboride shouldn't be too hard to form (type II, cuprate superconductors might be quite a bit more of a chore). One thing, though, that concerns me: with such a high Q, the bandwidth would be very narrow, and that unless the microwave source is extremely well matched to the cavity's resonance, it will require tuning. From my experience with tuning high-Q antennas in amateur radio, I know that it is possible to just slide right past the point of resonance if tuning is too coarse. One solution to the problem might be to temporarily drop the Q, just so it's easier to find the proper range, and then gradually tighten it in fine tuning. Though I have a hunch that the highest-Q, available from superconducting cavities, might create such a shape bandwidth that none of our signal sources are going to be precise and stable enough to stay tuned to it, so we might have to always artificially drop the Q from what a superconducting cavity might be capable of. I haven't put this to the test, nor have I even done any numerical reasoning on the idea, but I think it's worth mentioning.From DYIer perspective.The Thermal Expansion Coefficient for copper is: 0.000017 (m/moC)http://hyperphysics.phy-astr.gsu.edu/hbase/tables/thexp.html#c1This TEC becomes a issue in the changing of the cavity length but also the warping of the hot zones within the copper at the modes points. If we were smarter we could build it of quartz (flashed with silver and gold) which is 28x less or some other 0o TEC material, but that becomes something expensive a DYier can't do.So a DYier can do a couple things, go low power which is tough to get any readings or go higher power and try to negate by design the issue of TEC. I think the best of both worlds would be negating the TEC thru design (I've tried to do) ... and make it superconducting but I'm going for up to 2 KW into the frustum.Right now I'm shooting for design control of the TEC and producing a clean RF through a modified magnetron inverter and removing the hot magnetron away from the frustum and feeding the RF into the frustum via antenna or waveguide. These designs have given a very high Q but it is to be seen if I can keep the higher Qs in a real world operation. Simple thought, lower Qs mean the incoming RF signal is absorbed into the frustum and turned into simply generating heat. Unless I want to drive this with a megawatt(s) klystron turning the frustum into a white hot effervescent accelerating stream of gas, that might give me acceleration but it's outside of the box and a simple rocket then.MgB2 electroplated onto SiC would be pretty stable at low cryogenic temp, though. Still not easy to do. Magnetrons have messy spectrum but you can clean them up with a PLL. It seems to me that a high-Q cavity is necessary for high power, otherwise there's going to be a lot of heat, possibly leading to mechanical failure/explosion. But unless that match is good, Q will be horribly high, leading to heat, and in the case of a superconductor, thermal runaway to disaster. So, a good design might have signal generator of adjustable power and frequency (but a good, clean sine wave), and the cavity be superconducting high-Q but have a tunable Q. At startup, power is low and Q is low. the frequency of the signal generator is tuned to the middle of resonance, then the Q is increased and power increased, and the cycle repeated until emdrive effect is strong.This requires that the adjustment of the Q is stable, and that it be protected against thermal runaway.If some of the about language/thought seems unclear, please excuse me, I haven't yet had my coffee
Quote from: R.W. Keyes on 10/01/2015 10:57 pmHi everyone, I've been away for a while, and I have tried to catch up but there's just so much to read.What is that general opinion about a high Q being necessary for the emdrive to work efficiently? I haven't seen much about going to the extremes of high-Q, such as superconducting cavities at cryogenic temperatures. I understand that such a cool temperature makes test conditions more difficult, but if high Q will result in greater efficiency, isn't this worth trying? Also, magnesium diboride shouldn't be too hard to form (type II, cuprate superconductors might be quite a bit more of a chore). One thing, though, that concerns me: with such a high Q, the bandwidth would be very narrow, and that unless the microwave source is extremely well matched to the cavity's resonance, it will require tuning. From my experience with tuning high-Q antennas in amateur radio, I know that it is possible to just slide right past the point of resonance if tuning is too coarse. One solution to the problem might be to temporarily drop the Q, just so it's easier to find the proper range, and then gradually tighten it in fine tuning. Though I have a hunch that the highest-Q, available from superconducting cavities, might create such a shape bandwidth that none of our signal sources are going to be precise and stable enough to stay tuned to it, so we might have to always artificially drop the Q from what a superconducting cavity might be capable of. I haven't put this to the test, nor have I even done any numerical reasoning on the idea, but I think it's worth mentioning.From DYIer perspective.The Thermal Expansion Coefficient for copper is: 0.000017 (m/moC)http://hyperphysics.phy-astr.gsu.edu/hbase/tables/thexp.html#c1This TEC becomes a issue in the changing of the cavity length but also the warping of the hot zones within the copper at the modes points. If we were smarter we could build it of quartz (flashed with silver and gold) which is 28x less or some other 0o TEC material, but that becomes something expensive a DYier can't do.So a DYier can do a couple things, go low power which is tough to get any readings or go higher power and try to negate by design the issue of TEC. I think the best of both worlds would be negating the TEC thru design (I've tried to do) ... and make it superconducting but I'm going for up to 2 KW into the frustum.Right now I'm shooting for design control of the TEC and producing a clean RF through a modified magnetron inverter and removing the hot magnetron away from the frustum and feeding the RF into the frustum via antenna or waveguide. These designs have given a very high Q but it is to be seen if I can keep the higher Qs in a real world operation. Simple thought, lower Qs mean the incoming RF signal is absorbed into the frustum and turned into simply generating heat. Unless I want to drive this with a megawatt(s) klystron turning the frustum into a white hot effervescent accelerating stream of gas, that might give me acceleration but it's outside of the box and a simple rocket then.
Hi everyone, I've been away for a while, and I have tried to catch up but there's just so much to read.What is that general opinion about a high Q being necessary for the emdrive to work efficiently? I haven't seen much about going to the extremes of high-Q, such as superconducting cavities at cryogenic temperatures. I understand that such a cool temperature makes test conditions more difficult, but if high Q will result in greater efficiency, isn't this worth trying? Also, magnesium diboride shouldn't be too hard to form (type II, cuprate superconductors might be quite a bit more of a chore). One thing, though, that concerns me: with such a high Q, the bandwidth would be very narrow, and that unless the microwave source is extremely well matched to the cavity's resonance, it will require tuning. From my experience with tuning high-Q antennas in amateur radio, I know that it is possible to just slide right past the point of resonance if tuning is too coarse. One solution to the problem might be to temporarily drop the Q, just so it's easier to find the proper range, and then gradually tighten it in fine tuning. Though I have a hunch that the highest-Q, available from superconducting cavities, might create such a shape bandwidth that none of our signal sources are going to be precise and stable enough to stay tuned to it, so we might have to always artificially drop the Q from what a superconducting cavity might be capable of. I haven't put this to the test, nor have I even done any numerical reasoning on the idea, but I think it's worth mentioning.
Quote from: R.W. Keyes on 10/02/2015 03:57 pmQuote from: SeeShells on 10/02/2015 11:38 amQuote from: R.W. Keyes on 10/01/2015 10:57 pmHi everyone, I've been away for a while, and I have tried to catch up but there's just so much to read.What is that general opinion about a high Q being necessary for the emdrive to work efficiently? I haven't seen much about going to the extremes of high-Q, such as superconducting cavities at cryogenic temperatures. I understand that such a cool temperature makes test conditions more difficult, but if high Q will result in greater efficiency, isn't this worth trying? Also, magnesium diboride shouldn't be too hard to form (type II, cuprate superconductors might be quite a bit more of a chore). One thing, though, that concerns me: with such a high Q, the bandwidth would be very narrow, and that unless the microwave source is extremely well matched to the cavity's resonance, it will require tuning. From my experience with tuning high-Q antennas in amateur radio, I know that it is possible to just slide right past the point of resonance if tuning is too coarse. One solution to the problem might be to temporarily drop the Q, just so it's easier to find the proper range, and then gradually tighten it in fine tuning. Though I have a hunch that the highest-Q, available from superconducting cavities, might create such a shape bandwidth that none of our signal sources are going to be precise and stable enough to stay tuned to it, so we might have to always artificially drop the Q from what a superconducting cavity might be capable of. I haven't put this to the test, nor have I even done any numerical reasoning on the idea, but I think it's worth mentioning.From DYIer perspective.The Thermal Expansion Coefficient for copper is: 0.000017 (m/moC)http://hyperphysics.phy-astr.gsu.edu/hbase/tables/thexp.html#c1This TEC becomes a issue in the changing of the cavity length but also the warping of the hot zones within the copper at the modes points. If we were smarter we could build it of quartz (flashed with silver and gold) which is 28x less or some other 0o TEC material, but that becomes something expensive a DYier can't do.So a DYier can do a couple things, go low power which is tough to get any readings or go higher power and try to negate by design the issue of TEC. I think the best of both worlds would be negating the TEC thru design (I've tried to do) ... and make it superconducting but I'm going for up to 2 KW into the frustum.Right now I'm shooting for design control of the TEC and producing a clean RF through a modified magnetron inverter and removing the hot magnetron away from the frustum and feeding the RF into the frustum via antenna or waveguide. These designs have given a very high Q but it is to be seen if I can keep the higher Qs in a real world operation. Simple thought, lower Qs mean the incoming RF signal is absorbed into the frustum and turned into simply generating heat. Unless I want to drive this with a megawatt(s) klystron turning the frustum into a white hot effervescent accelerating stream of gas, that might give me acceleration but it's outside of the box and a simple rocket then.MgB2 electroplated onto SiC would be pretty stable at low cryogenic temp, though. Still not easy to do. Magnetrons have messy spectrum but you can clean them up with a PLL. It seems to me that a high-Q cavity is necessary for high power, otherwise there's going to be a lot of heat, possibly leading to mechanical failure/explosion. But unless that match is good, Q will be horribly high, leading to heat, and in the case of a superconductor, thermal runaway to disaster. So, a good design might have signal generator of adjustable power and frequency (but a good, clean sine wave), and the cavity be superconducting high-Q but have a tunable Q. At startup, power is low and Q is low. the frequency of the signal generator is tuned to the middle of resonance, then the Q is increased and power increased, and the cycle repeated until emdrive effect is strong.This requires that the adjustment of the Q is stable, and that it be protected against thermal runaway.If some of the about language/thought seems unclear, please excuse me, I haven't yet had my coffee"It seems to me that a high-Q cavity is necessary for high power, otherwise there's going to be a lot of heat, possibly leading to mechanical failure/explosion. "Yes, that's what I said. There are three ways one can assure the maintenance of a high Q system and this is true for room temperature drives and superconducting. First, build it out of a nearly 0 degee TEC material. There are plenty of them to choose from. All are expensive and not easy to make but they can be done.Second. As the frustum heats up and deforms changing the resonate window, shift the incoming frequency to center it again. It will still heat up and deform the frustum in the growth of the side walls and in the deformation of heated zones when generated modes are made. It is unavoidable. Third. Knowing the frustum is going to heat up and thermally expand regardless of where you shift the incoming frequency to match. The frustum assures in it's operation that the wave formed modes will collapse and or the different modes will interact with each other. That interaction and or collapse when it happens in a destructive way creates heat. It is in it's design nature to heat up. Design for the thermal expansion.What I've done in this design is realize that the frustum will continue to heat as long as RF is pumped into the chamber, even when the incoming signal is phased locked to Q. I capture the two end plates with a quartz rod between running through the center. Quartz is virtually transparent to microwaves and has a very low TEC for growth. (see pic) The large plate is secured to the sidewall with the quartz rod freely running through it and attaches to the small endplate which the tuning micrometer can change the resonate length by sliding the small plate in and out of the tubular tuning chamber at the top. (see pic).The frustum is going to heat up, the sidewalls are going to expand and the endplates are going to want to deform from mode generation. Capture the endplates setting the resonance distance and secure the copper endplates onto a ceramic plate keeping them from warping. The copper side wall can slide past the small endplate that has a sliding gasket of beryllium copper. Let it expand as its nature to do so but keep the resonance distance between the plates within the magnetron's RF envelope. This can be used at a future date along with a RF locked Q and do it at room temperature.Shell
Quote from: SeeShells on 10/02/2015 07:35 pmQuote from: R.W. Keyes on 10/02/2015 03:57 pmQuote from: SeeShells on 10/02/2015 11:38 amQuote from: R.W. Keyes on 10/01/2015 10:57 pmHeat caused by the MW energy is everywhere in such high power experiments, the question is where it is:@ low Q the power will be reflected and heats the magnetron/source@ matched resonance frequency it will heat the frustumpoint But i think your tunable design is great for this experiments, also the modified loop antenna(my favorite design for the TE01p mode)! You know with kind of antenna think about
Quote from: R.W. Keyes on 10/02/2015 03:57 pmQuote from: SeeShells on 10/02/2015 11:38 amQuote from: R.W. Keyes on 10/01/2015 10:57 pm
Quote from: SeeShells on 10/02/2015 11:38 amQuote from: R.W. Keyes on 10/01/2015 10:57 pm
Quote from: R.W. Keyes on 10/01/2015 10:57 pm
Dual injectors... see meep animation attached.Shell
{snip}Here's the problem, I said that each bounce wants to redshift the light by "about" so many hertz. For light, one hertz is one plank constant. The plank constant is the smallest possible unit of energy in the Universe. It has to be an integer.{snip}
Quote from: SeeShells on 10/02/2015 08:16 pmDual injectors... see meep animation attached.ShellDumb questions as a data miner:1. Does that animated gif show a field propogation from one end to the other?2. If so, is there a thermal gradient that follows that propogation?3. If so, on the outside of the wall, would there be a comparable thermal gradient that also propogates?
Shell:Thinking about your sliding end plate and the effect of uneven heating. Since expansion of copper is linear with change in temperature, if both the small end circumference of the frustum and the diameter of the small end plate are heated equally, the relative change in the diameters will be the same. Unfortunately, if the end plate heats more than the small end circumference of the frustum, won't the end plate diameter expand then bind rather than move? I know you're thorough and so must have considered this. aero