Quote from: SeeShells on 08/02/2015 01:07 amQuote from: Rodal on 08/02/2015 12:31 amThe Yang/Shell dimensions with cone half angle at 6 degrees had TM113 and TE012 both resonate at near 2.45 GHz.This geometry (now officially entered into the World Book Of Paranormal EM Drive Phenomena) resonates with TE012 at 2.45 GHz but the TM11 modes are further apart:TM112= 2.23227 GHzTM113= 2.64095 GHz So aero will have to model it in Meep with a loop antenna or we have no resonance at 2.45 GHzGo ahead make me feel bad Jose', I'm about ready to take a brick to the first frustum I'm so frustrumed. Just as long as you don't throw the brick at me
Quote from: Rodal on 08/02/2015 12:31 amThe Yang/Shell dimensions with cone half angle at 6 degrees had TM113 and TE012 both resonate at near 2.45 GHz.This geometry (now officially entered into the World Book Of Paranormal EM Drive Phenomena) resonates with TE012 at 2.45 GHz but the TM11 modes are further apart:TM112= 2.23227 GHzTM113= 2.64095 GHz So aero will have to model it in Meep with a loop antenna or we have no resonance at 2.45 GHzGo ahead make me feel bad Jose', I'm about ready to take a brick to the first frustum I'm so frustrumed.
The Yang/Shell dimensions with cone half angle at 6 degrees had TM113 and TE012 both resonate at near 2.45 GHz.This geometry (now officially entered into the World Book Of Paranormal EM Drive Phenomena) resonates with TE012 at 2.45 GHz but the TM11 modes are further apart:TM112= 2.23227 GHzTM113= 2.64095 GHz So aero will have to model it in Meep with a loop antenna or we have no resonance at 2.45 GHz
Quote from: Rodal on 08/02/2015 01:12 amQuote from: SeeShells on 08/02/2015 01:07 amQuote from: Rodal on 08/02/2015 12:31 amThe Yang/Shell dimensions with cone half angle at 6 degrees had TM113 and TE012 both resonate at near 2.45 GHz.This geometry (now officially entered into the World Book Of Paranormal EM Drive Phenomena) resonates with TE012 at 2.45 GHz but the TM11 modes are further apart:TM112= 2.23227 GHzTM113= 2.64095 GHz So aero will have to model it in Meep with a loop antenna or we have no resonance at 2.45 GHzGo ahead make me feel bad Jose', I'm about ready to take a brick to the first frustum I'm so frustrumed. Just as long as you don't throw the brick at me Like I said, I don't build anything until I understand what it is I'm building. I don't wing-it, I'm a tinker-er. I'll build a prototype of something I can predict and then tinker with it until it works or I understand why it doesn't. Although, I must admit it's a lot easier simulating a printed circuit board than it is building mechanical models. Don't get too frustrated Shell, it's a journey.Todd
When I looked at the design equations, I reckoned that the big/small diameter ratio should be as big as possible, which means maximising the half-angle. No idea if this has any effect.
Quote from: deltaMass on 08/02/2015 01:32 amWhen I looked at the design equations, I reckoned that the big/small diameter ratio should be as big as possible, which means maximising the half-angle. No idea if this has any effect.True, but if you look at the impedance plots from Z&F, there is very little room along k*r to operate on a slope for any angle over 15 deg, (pi/12). More than that and it starts to look like a flat plate. IMO, Shell's 6 deg frustum is probably not a bad design if she can get the k*r at the small end around 18 and the k*r at the big end around 30. Todd
Quote from: WarpTech on 08/02/2015 01:48 amQuote from: deltaMass on 08/02/2015 01:32 amWhen I looked at the design equations, I reckoned that the big/small diameter ratio should be as big as possible, which means maximising the half-angle. No idea if this has any effect.True, but if you look at the impedance plots from Z&F, there is very little room along k*r to operate on a slope for any angle over 15 deg, (pi/12). More than that and it starts to look like a flat plate. IMO, Shell's 6 deg frustum is probably not a bad design if she can get the k*r at the small end around 18 and the k*r at the big end around 30. Todd Shawyer and McCulloch both have (for different reasons) a constraint on length: the length cannot be too long. Independently, that's what the calculations show. If you have a cone with a low angle (6 degrees) and you extend it, you end up with a large region near the small base that is just sitting there not resonating. It becomes useless volume. Like you said: you want to get to the point where the force at the small base is zero, not much further, any further is wasted. Too low angle == bad. If not extended, looks like a cylinder. If extended to the apex, it is an extremely long cone with a large portion of the volume sitting there doing nothing good: no Q resonance near the apex. Modes persist but they become evanescent way before reaching the small base. So the ending portion just sits there doing no good.
Quote from: Rodal on 08/02/2015 02:01 amQuote from: WarpTech on 08/02/2015 01:48 amQuote from: deltaMass on 08/02/2015 01:32 amWhen I looked at the design equations, I reckoned that the big/small diameter ratio should be as big as possible, which means maximising the half-angle. No idea if this has any effect.True, but if you look at the impedance plots from Z&F, there is very little room along k*r to operate on a slope for any angle over 15 deg, (pi/12). More than that and it starts to look like a flat plate. IMO, Shell's 6 deg frustum is probably not a bad design if she can get the k*r at the small end around 18 and the k*r at the big end around 30. Todd Shawyer and McCulloch both have (for different reasons) a constraint on length: the length cannot be too long. Independently, that's what the calculations show. If you have a cone with a low angle (6 degrees) and you extend it, you end up with a large region near the small base that is just sitting there not resonating. It becomes useless volume. Like you said: you want to get to the point where the force at the small base is zero, not much further, any further is wasted. Too low angle == bad. If not extended, looks like a cylinder. If extended to the apex, it is an extremely long cone with a large portion of the volume sitting there doing nothing good: no Q resonance near the apex. Modes persist but they become evanescent way before reaching the small base. So the ending portion just sits there doing no good.Understood, so at Shell's cone angle what is the shortest section that can be made to resonate at 2.45GHz? And how small does the small end need to be, such that nothing reaches the small end?Todd
Quote from: WarpTech on 08/02/2015 01:20 amQuote from: Rodal on 08/02/2015 01:12 amQuote from: SeeShells on 08/02/2015 01:07 amQuote from: Rodal on 08/02/2015 12:31 amThe Yang/Shell dimensions with cone half angle at 6 degrees had TM113 and TE012 both resonate at near 2.45 GHz.This geometry (now officially entered into the World Book Of Paranormal EM Drive Phenomena) resonates with TE012 at 2.45 GHz but the TM11 modes are further apart:TM112= 2.23227 GHzTM113= 2.64095 GHz So aero will have to model it in Meep with a loop antenna or we have no resonance at 2.45 GHzGo ahead make me feel bad Jose', I'm about ready to take a brick to the first frustum I'm so frustrumed. Just as long as you don't throw the brick at me Like I said, I don't build anything until I understand what it is I'm building. I don't wing-it, I'm a tinker-er. I'll build a prototype of something I can predict and then tinker with it until it works or I understand why it doesn't. Although, I must admit it's a lot easier simulating a printed circuit board than it is building mechanical models. Don't get too frustrated Shell, it's a journey.ToddMicrowave cavities are not my forte, I can design a heck of a test rig but the old math is taking so much longer than it did the first time. sigh. Thanks...Shell
I made what I hope is a loop antenna out of 20 gauge perfect metal wire. The loop outside diameter is 14 mm, and 20 gauge wire diameter is 0.814 mm. I proceeded by making a hollow cylinder 14 mm diameter, with 0.814 mm thick sidewalls and 0.814 mm long. I then cut a section 0.814 mm long from the cylindar side. I placed a current source across this gap 1.628 mm long.I placed this “thing” in the center of the lattice with absorbing boundary layers on all 6 sides and excited it with an ez current source at 1.93 GHz. The lattice is 1.8 wavelengths on a side and the boundary layer is 0.5 wavelengths thick.I made a meep run and made images of all 3 field views of all 6 EM field components.Only I don't know what the field pattern should look like. Do the images look like they were generated by a loop antenna?Views are here as is my control file (its also attached):https://drive.google.com/folderview?id=0B1XizxEfB23tfk9TOE9HV29EeGJDQkVucm9RY2Fxb3RxaGI0RDFuMzh6MXhoSWN2aU9Lanc&usp=sharing
Quote from: aero on 08/02/2015 02:42 amI made what I hope is a loop antenna out of 20 gauge perfect metal wire. The loop outside diameter is 14 mm, and 20 gauge wire diameter is 0.814 mm. I proceeded by making a hollow cylinder 14 mm diameter, with 0.814 mm thick sidewalls and 0.814 mm long. I then cut a section 0.814 mm long from the cylindar side. I placed a current source across this gap 1.628 mm long.I placed this “thing” in the center of the lattice with absorbing boundary layers on all 6 sides and excited it with an ez current source at 1.93 GHz. The lattice is 1.8 wavelengths on a side and the boundary layer is 0.5 wavelengths thick.I made a meep run and made images of all 3 field views of all 6 EM field components.Only I don't know what the field pattern should look like. Do the images look like they were generated by a loop antenna?Views are here as is my control file (its also attached):https://drive.google.com/folderview?id=0B1XizxEfB23tfk9TOE9HV29EeGJDQkVucm9RY2Fxb3RxaGI0RDFuMzh6MXhoSWN2aU9Lanc&usp=sharingSorry I cannot give you any feedback without examining all the usual csv files because to understand the mode shapes I need to have access to numerical data. The Meep image output do not have numerical data associated with the contour levels, and color contours get repeated and hence not way for me to understand what is going on.
Quote from: Rodal on 08/02/2015 02:58 amQuote from: aero on 08/02/2015 02:42 amI made what I hope is a loop antenna out of 20 gauge perfect metal wire. The loop outside diameter is 14 mm, and 20 gauge wire diameter is 0.814 mm. I proceeded by making a hollow cylinder 14 mm diameter, with 0.814 mm thick sidewalls and 0.814 mm long. I then cut a section 0.814 mm long from the cylindar side. I placed a current source across this gap 1.628 mm long.I placed this “thing” in the center of the lattice with absorbing boundary layers on all 6 sides and excited it with an ez current source at 1.93 GHz. The lattice is 1.8 wavelengths on a side and the boundary layer is 0.5 wavelengths thick.I made a meep run and made images of all 3 field views of all 6 EM field components.Only I don't know what the field pattern should look like. Do the images look like they were generated by a loop antenna?Views are here as is my control file (its also attached):https://drive.google.com/folderview?id=0B1XizxEfB23tfk9TOE9HV29EeGJDQkVucm9RY2Fxb3RxaGI0RDFuMzh6MXhoSWN2aU9Lanc&usp=sharingSorry I cannot give you any feedback without examining all the usual csv files because to understand the mode shapes I need to have access to numerical data. The Meep image output do not have numerical data associated with the contour levels, and color contours get repeated and hence not way for me to understand what is going on.Well, I copied the EW antenna geometry so I could put it into the Brady model, but before I do that I was hoping for some little confirmation or guidance from the forum. I'll give it some time.
Shawyer and McCulloch both have (for different reasons) a constraint on length: the length cannot be too long. Independently, that's what the calculations show. If you have a cone with a low angle (6 degrees) and you extend it, you end up with a large region near the small base that is just sitting there not resonating. It becomes useless volume. Like you said: you want to get to the point where the force at the small base is zero.But hold it, at that point, not much further, any further is wasted. Too low angle == bad. If not extended, looks like a cylinder. If extended to the apex, it is an extremely long cone with a large portion of the volume sitting there doing nothing good: no Q resonance near the apex. Modes persist but they become evanescent way before reaching the small base. So the ending portion just sits there doing no good.Here is the insectoid overlord again. The useful part are the eyes and the brain. The resonance takes place there. Too long a pointy chin (too much purple) is wasted volume:
NSF-1701 3rd static temp test video. I learned the IR gun is not useful at 3 feet. Also the quick drop of temp when mag cycles off is false reading. Regardless, saw some interesting arcing at full power at 1 minute duration. Frustum itself remained at low temp. Mag went to about 160°C.
Yang's frustum has the following dimensions:- cavity length (m): 0.24- big diameter (m): 0.201- small diameter (m): 0.1492In particular, the big end is smaller than the height, not larger.
Pardon me but if the long end of an optimal frustrum is twice the size of the short end then doesn't that imply that the the inverse square law dictates the optimal design of the frustrum?