Quote from: dustinthewind on 07/19/2015 06:57 pmMy suspicion is that one of these would provide more propulsion than the other. I have got a question. Are these cavities of a pure dielectrically type (non metallic plates between them)? If not there may be a problem with that idea: If there are metallic plates the penetration depth is only a few µm..Was your idea to transform the SHORT at the end plate to be an OPEN a quarter wavelength away? I think there is a physically short at the end plate of the second cavity because there is a metallic plate also(boundary conditions). The currents are not at the outside of a metallic cavity resonator(for this high frequencies).
My suspicion is that one of these would provide more propulsion than the other.
Quote from: X_RaY on 07/19/2015 07:24 pmQuote from: dustinthewind on 07/19/2015 06:57 pmMy suspicion is that one of these would provide more propulsion than the other. I have got a question. Are these cavities of a pure dielectrically type (non metallic plates between them)? If not there may be a problem with that idea: If there are metallic plates the penetration depth is only a few µm..Was your idea to transform the SHORT at the end plate to be an OPEN a quarter wavelength away? I think there is a physically short at the end plate of the second cavity because there is a metallic plate also(boundary conditions). The currents are not at the outside of a metallic cavity resonator(for this high frequencies).the picture of the 2 cavities is of only space and metal. The reason I think radiation would tunnel is because of interaction of evanescent currents should attenuate current in one cavity and amplify current in the other to bring them both to some happy medium where their currents want to circulate in unison, however, the radiation fights this. Because the currents are now no longer circulating only in response to the radiation and are out of phase with the radiation in the cavities. The cavities can no longer reflect the radiation as effectively. As a result some radiation should tunnel from one cavity to the next but now the radiation I think as it tunnels is also out of phase with radiation inside the new cavity. The radiation from the 1st cavity now in the 2nd cavity traveling and still out of phase may encounter currents in the back plate of the 2nd cavity out of phase with it. As a result a portion of its radiation may escape that cavity altogether. This was my line of thinking but maybe it's flawed or I am not understanding your question. An alternative to this was with a single cavity and two antennas where I was hoping to open up the cavity to transmit radiation (Radio frequency spectrum) that did use dielectrics to slow light but also used metal. Attached the image.
You guys are in luck, as NSF-1701 is easily reconfigurable. Here's what I propose. Assymetrical placement of monopole in both the small base and big base. This will not be frustum side insertion, but parallel to axis, offset from centerline for assymetry. My reccomendation is 1/4 wavelength from frustum sidewall to realize 50 ohm match. It will be more like nasa insertion but not a perpendicular coupling loop. For now, polarity is parallel to frustum length axis...the easiest way to swap ends for insertion tests. I'll start at a large diameter insertion for static temp testing of magnetron core. Now, off to get some more solder...IR thermometer arrives mid week, will video static test. Max core temp is 160°C. Exceeding that typifies poor impedance match according to my research. If matched properly, power-up can exceed 5 minutes.
Even with very modest k (say 10-6 N/W) one can achieve excellent mission performance when lots of power is available. Let's go to Pluto (40 AU, 100 Kg). With 1 MW power it takes 1.1 years and maximum speed is 0.1%c.
Quote from: deltaMass on 07/15/2015 05:55 amEven with very modest k (say 10-6 N/W) one can achieve excellent mission performance when lots of power is available. Let's go to Pluto (40 AU, 100 Kg). With 1 MW power it takes 1.1 years and maximum speed is 0.1%c.Uhh, and how do you fit a 1 MW power plant into 100 kg?
Quote from: Prunesquallor on 07/19/2015 08:52 pmQuote from: deltaMass on 07/15/2015 05:55 amEven with very modest k (say 10-6 N/W) one can achieve excellent mission performance when lots of power is available. Let's go to Pluto (40 AU, 100 Kg). With 1 MW power it takes 1.1 years and maximum speed is 0.1%c.Uhh, and how do you fit a 1 MW power plant into 100 kg?That took long enough Well, of course using an overunity EmDrive power generator! You can have as much power as you like
Quote from: dustinthewind on 07/19/2015 07:42 pmQuote from: X_RaY on 07/19/2015 07:24 pmQuote from: dustinthewind on 07/19/2015 06:57 pmMy suspicion is that one of these would provide more propulsion than the other. I have got a question. Are these cavities of a pure dielectrically type (non metallic plates between them)? If not there may be a problem with that idea: If there are metallic plates the penetration depth is only a few µm..Was your idea to transform the SHORT at the end plate to be an OPEN a quarter wavelength away? I think there is a physically short at the end plate of the second cavity because there is a metallic plate also(boundary conditions). The currents are not at the outside of a metallic cavity resonator(for this high frequencies).the picture of the 2 cavities is of only space and metal. The reason I think radiation would tunnel is because of interaction of evanescent currents should attenuate current in one cavity and amplify current in the other to bring them both to some happy medium where their currents want to circulate in unison, however, the radiation fights this. Because the currents are now no longer circulating only in response to the radiation and are out of phase with the radiation in the cavities. The cavities can no longer reflect the radiation as effectively. As a result some radiation should tunnel from one cavity to the next but now the radiation I think as it tunnels is also out of phase with radiation inside the new cavity. The radiation from the 1st cavity now in the 2nd cavity traveling and still out of phase may encounter currents in the back plate of the 2nd cavity out of phase with it. As a result a portion of its radiation may escape that cavity altogether. This was my line of thinking but maybe it's flawed or I am not understanding your question. An alternative to this was with a single cavity and two antennas where I was hoping to open up the cavity to transmit radiation (Radio frequency spectrum) that did use dielectrics to slow light but also used metal. Attached the image. OK if there are 2 antennas, one inside, one outside the cavity out of phase. Let us think there may be some photons entering the metallic cavity from the outer dielectric (very thin metal film between cavity and dielectric ~1µm) the resonance inside the metal cavity will be degenerate by modification of the second stimulation of some cavity eigenvalue. Its just wave-mixing. If there are in phase at a position there will be constructive interference..I think if the metal in the real is thicker this will not be the case. There is only the effect of a photon rocket based of the antenna outside in the dielectrica...edit: http://arxiv.org/pdf/physics/0311061v7.pdfThere is a diagram of the group velocity at cutoff diameter... IMHO thats for examplethe why evanecent waves are in dicussion for the conical cavity Sorry, the magnetic antenna you've draw doesn't work. The wave will be splitted into two parts and propagate along the wire, at half the way in the loop they will interact to form a maximum (that works like an electrically dipole). A magnetic antenna loop have to be in contact to the opposite potential at the end of the loop, whatever capacitive or galvanic...
Quote from: deltaMass on 07/19/2015 09:14 pmQuote from: Prunesquallor on 07/19/2015 08:52 pmQuote from: deltaMass on 07/15/2015 05:55 amEven with very modest k (say 10-6 N/W) one can achieve excellent mission performance when lots of power is available. Let's go to Pluto (40 AU, 100 Kg). With 1 MW power it takes 1.1 years and maximum speed is 0.1%c.Uhh, and how do you fit a 1 MW power plant into 100 kg?That took long enough Well, of course using an overunity EmDrive power generator! You can have as much power as you like Sorry :-) was off the grid for 1 (one!) week and was trying to catch up on 30 (thirty!) page of posts. BTW I'm working on a write-up of the acceleration one would need from something like a Cubesat to unambiguously see orbital trajectory effects in the presence of drag. Hope to make it available in the next week or so.
Quote from: Prunesquallor on 07/19/2015 10:13 pm...snip...lots...Sorry :-) was off the grid for 1 (one!) week and was trying to catch up on 30 (thirty!) page of posts. BTW I'm working on a write-up of the acceleration one would need from something like a Cubesat to unambiguously see orbital trajectory effects in the presence of drag. Hope to make it available in the next week or so.I have not seen that analysis and would very much welcome it....snip...There are at least two important issues to bear in mind with that:1. Determination of position in realtime2. Determination of perturbation and error sources....even more pruning...
...snip...lots...Sorry :-) was off the grid for 1 (one!) week and was trying to catch up on 30 (thirty!) page of posts. BTW I'm working on a write-up of the acceleration one would need from something like a Cubesat to unambiguously see orbital trajectory effects in the presence of drag. Hope to make it available in the next week or so.
Quote from: deltaMass on 07/19/2015 10:41 pmQuote from: Prunesquallor on 07/19/2015 10:13 pm...snip...lots...Sorry :-) was off the grid for 1 (one!) week and was trying to catch up on 30 (thirty!) page of posts. BTW I'm working on a write-up of the acceleration one would need from something like a Cubesat to unambiguously see orbital trajectory effects in the presence of drag. Hope to make it available in the next week or so.I have not seen that analysis and would very much welcome it....snip...There are at least two important issues to bear in mind with that:1. Determination of position in realtime2. Determination of perturbation and error sources....even more pruning...It can be done way simpler than that. A satellite emitting a carrier on an S-Band omnidirectional antenna. Ground can detect a change in frequency and therefore velocity down to mm/s. We did that on LCROSS showing that the water evaporating off the Centaur upper stage was pushing it and the shepherding spacecraft around. I was kinda dumb-founded that they could detect the delta V to that degree...
Quote from: rfmwguy on 07/19/2015 06:42 pmYou guys are in luck, as NSF-1701 is easily reconfigurable. Here's what I propose. Assymetrical placement of monopole in both the small base and big base. This will not be frustum side insertion, but parallel to axis, offset from centerline for assymetry. My reccomendation is 1/4 wavelength from frustum sidewall to realize 50 ohm match. It will be more like nasa insertion but not a perpendicular coupling loop. For now, polarity is parallel to frustum length axis...the easiest way to swap ends for insertion tests. I'll start at a large diameter insertion for static temp testing of magnetron core. Now, off to get some more solder...IR thermometer arrives mid week, will video static test. Max core temp is 160°C. Exceeding that typifies poor impedance match according to my research. If matched properly, power-up can exceed 5 minutes.So for a meep run of that, would the change be from (set! antSIx (- (/ (* high .0254) 2) (/ (/ csi fsi) 4))) to (set! antSIx (* 0.25 wl_meep) or (set! antSIx 0) ?
Quote from: Prunesquallor on 07/19/2015 10:13 pmQuote from: deltaMass on 07/19/2015 09:14 pmQuote from: Prunesquallor on 07/19/2015 08:52 pmQuote from: deltaMass on 07/15/2015 05:55 amEven with very modest k (say 10-6 N/W) one can achieve excellent mission performance when lots of power is available. Let's go to Pluto (40 AU, 100 Kg). With 1 MW power it takes 1.1 years and maximum speed is 0.1%c.Uhh, and how do you fit a 1 MW power plant into 100 kg?That took long enough Well, of course using an overunity EmDrive power generator! You can have as much power as you like Sorry :-) was off the grid for 1 (one!) week and was trying to catch up on 30 (thirty!) page of posts. BTW I'm working on a write-up of the acceleration one would need from something like a Cubesat to unambiguously see orbital trajectory effects in the presence of drag. Hope to make it available in the next week or so.I have not seen that analysis and would very much welcome it.There are at least two important issues to bear in mind with that:1. Determination of position in realtime2. Determination of perturbation and error sources.It seems to me that much of such designs immediately simplifies out when two identical craft are flown close by one another. The trade-off for "close" isa) not so close that e/m or gravitational perturbations become significant between themb) not so far away that the local environment is significantly changed (gravity, solar wind, solar flux, residual atmosphere, etc.)The craft are outfitted with LIDAR and comms to support that data (one may contain a dummy to get back to "identical"). At predetermined times, one is switched on, and ditto off.I think that's the best that can be done. We've factored out the local environment and are sensing only a difference between a powered and an unpowered module. The question is what sensitivity can be expected?An alternative to LIDAR occurs to me that has a couple of advantages - some sort of instrumented high tech spring equivalent. This is cheaper and occupies less volume (a CubeSat consideration) than LIDAR, and also ensures that unforeseen drift does not occur between them due to an imperfect twin launch. A slight disadvantage accrues with this spring idea in that there will always be a finite almost-perfectly-undamped oscillation in their separation, since the spring operates in both compression and in expansion. Note that a bungee cord equivalent would not be a good idea because it is unable to provide mutual repulsion.An even simpler differencing protocol obtains by equipping both craft with an accelerometer and comms to support its data. Probably the best bet. The flight profile would be:1. both off2. A on, B off3. A off, B on (to catch up)Lather, rinse, repeat.The main problem is going to be rotation. The thrust vector needs to be in a defined direction - somehow.
Quote from: X_RaY on 07/19/2015 08:08 pmQuote from: dustinthewind on 07/19/2015 07:42 pmQuote from: X_RaY on 07/19/2015 07:24 pmQuote from: dustinthewind on 07/19/2015 06:57 pmMy suspicion is that one of these would provide more propulsion than the other. I have got a question. Are these cavities of a pure dielectrically type (non metallic plates between them)? If not there may be a problem with that idea: If there are metallic plates the penetration depth is only a few µm..Was your idea to transform the SHORT at the end plate to be an OPEN a quarter wavelength away? I think there is a physically short at the end plate of the second cavity because there is a metallic plate also(boundary conditions). The currents are not at the outside of a metallic cavity resonator(for this high frequencies).the picture of the 2 cavities is of only space and metal. The reason I think radiation would tunnel is because of interaction of evanescent currents should attenuate current in one cavity and amplify current in the other to bring them both to some happy medium where their currents want to circulate in unison, however, the radiation fights this. Because the currents are now no longer circulating only in response to the radiation and are out of phase with the radiation in the cavities. The cavities can no longer reflect the radiation as effectively. As a result some radiation should tunnel from one cavity to the next but now the radiation I think as it tunnels is also out of phase with radiation inside the new cavity. The radiation from the 1st cavity now in the 2nd cavity traveling and still out of phase may encounter currents in the back plate of the 2nd cavity out of phase with it. As a result a portion of its radiation may escape that cavity altogether. This was my line of thinking but maybe it's flawed or I am not understanding your question. An alternative to this was with a single cavity and two antennas where I was hoping to open up the cavity to transmit radiation (Radio frequency spectrum) that did use dielectrics to slow light but also used metal. Attached the image. OK if there are 2 antennas, one inside, one outside the cavity out of phase. Let us think there may be some photons entering the metallic cavity from the outer dielectric (very thin metal film between cavity and dielectric ~1µm) the resonance inside the metal cavity will be degenerate by modification of the second stimulation of some cavity eigenvalue. Its just wave-mixing. If there are in phase at a position there will be constructive interference..I think if the metal in the real is thicker this will not be the case. There is only the effect of a photon rocket based of the antenna outside in the dielectrica...edit: http://arxiv.org/pdf/physics/0311061v7.pdfThere is a diagram of the group velocity at cutoff diameter... IMHO thats for examplethe why evanecent waves are in dicussion for the conical cavity Sorry, the magnetic antenna you've draw doesn't work. The wave will be splitted into two parts and propagate along the wire, at half the way in the loop they will interact to form a maximum (that works like an electrically dipole). A magnetic antenna loop have to be in contact to the opposite potential at the end of the loop, whatever capacitive or galvanic...One of the reasons stating that the near field propagates faster than light bothers me is because for a single charge the magnetic field decreases by 1/r^2 as given by the Biot-Savart law. By induction then so does the resulting electric field. From the electric field of an accelerating charge can be derived the electric field of light and is done so by Edward Purcell in his book "Electricity and Magnetism" in the appendix. As a result the magnetic field of the charge is directly related to the light. Stating that the near field propagates faster than light while the light only propagates at light speed bothers me as a result because either I am not understanding what the near field is or this understanding of light is flawed. http://www.amazon.com/Electricity-Magnetism-Edward-M-Purcell/dp/1107014026I can understand group velocities being super-luminal as the waves them selves are not super-luminal but for the near-field of a single charge to propagate super-luminal is beyond me at the moment.