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#1
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Cecil Moore wrote:
Reg Edwards wrote: It may be of interest to antagonists in the "current through coils" civil war. The nature of traveling wave current and standing wave current is different. Does your program take that into account? The "current through coils" argument boils down to the ones who understand standing wave currents in a standing wave antenna and those who refuse to take the time to understand. Quoting "Optics", by Hecht: "E(x,t) = 2Eo*sin(kx)*cos(wt) This is the equation for a STANDING or STATIONARY WAVE, as opposed to a traveling wave (Fig. 7.10). Its profile does not move through space. ... [The phase] doesn't rotate at all, and the resultant wave it represents doesn't progress through space - it's a standing wave." Until the gurus take the time to understand the nature of standing waves in standing waves antennas, they will keep committing the same mental blunders over and over. Hecht forgot to put the phase difference in his formula. It's no wonder there's no phase information in your standing waves, Cecil, Hecht left it out. Not only that, but where did he get the idea that it was sin(kx) instead of cos(kx). I understand Hecht is a good old boy, but I'd like to see his derivations. 73, Tom Donaly, KA6RUH |
#2
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Tom Donaly wrote:
Hecht forgot to put the phase difference in his formula. It's no wonder there's no phase information in your standing waves, Cecil, Hecht left it out. You are mistaken. If Hecht left it out then so did Gene Fuller. I suggest you listen to Gene when he says: Regarding the cos(kz)*cos(wt) terms in the standing wave equation: Gene Fuller, W4SZ wrote: In a standing wave antenna problem, such as the one you describe, there is no remaining phase information. Any specific phase characteristics of the traveling waves died out when the startup transients died out. Phase is gone. Kaput. Vanished. Cannot be recovered. Never to be seen again. The only "phase" remaining is the cos (kz) term, which is really an amplitude description, not a phase. Not only that, but where did he get the idea that it was sin(kx) instead of cos(kx). I understand Hecht is a good old boy, but I'd like to see his derivations. Apparently, you are ignorant of the difference in conventions between optics and RF engineering. In optics, there is no current so there is no current changing phase at an open circuit. In optics, the M-field changes directions but not phase. In RF engineering, a change in direction of the H-field is considered to be a 180 degree phase shift. Both conventions are correct as long as one understands them. Your strange statement about Hecht above just proves your ignorance. -- 73, Cecil http://www.qsl.net/w5dxp |
#3
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Cecil Moore wrote:
Tom Donaly wrote: Hecht forgot to put the phase difference in his formula. It's no wonder there's no phase information in your standing waves, Cecil, Hecht left it out. You are mistaken. If Hecht left it out then so did Gene Fuller. I suggest you listen to Gene when he says: Regarding the cos(kz)*cos(wt) terms in the standing wave equation: Gene Fuller, W4SZ wrote: In a standing wave antenna problem, such as the one you describe, there is no remaining phase information. Any specific phase characteristics of the traveling waves died out when the startup transients died out. Phase is gone. Kaput. Vanished. Cannot be recovered. Never to be seen again. The only "phase" remaining is the cos (kz) term, which is really an amplitude description, not a phase. Not only that, but where did he get the idea that it was sin(kx) instead of cos(kx). I understand Hecht is a good old boy, but I'd like to see his derivations. Apparently, you are ignorant of the difference in conventions between optics and RF engineering. In optics, there is no current so there is no current changing phase at an open circuit. In optics, the M-field changes directions but not phase. In RF engineering, a change in direction of the H-field is considered to be a 180 degree phase shift. Both conventions are correct as long as one understands them. Your strange statement about Hecht above just proves your ignorance. Whatever. I'd still like to see his derivations. In your case, you're using the wrong equation anyway. What you really want is Beta*l, or the radian length of your transmission line. You can get that if you know, or can measure the usual parameters in the transmission line impedance equation, using that equation to solve for Beta*l. That won't prove your theory because you still haven't shown that any one transmission line model is unique in terms of substituting for your coil, but at least it'll give you something to do. 73, Tom Donaly, KA6RUH |
#4
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Tom Donaly wrote:
Whatever. I'd still like to see his derivations. "Optics", by Hecht, 4th edition, page 289. The intensity of a light beam is associated with the E-field so Hecht's equations are in relation to the E-field. Speaking of the light standing wave: "The composite disturbance is then: E = Eo[sin(kt+wt) + sin(kt-wt)] Applying the indentity sin A + sin B = 2 sin 1/2(A+B)*cos 1/2(A-B) E(x,t) = 2*Eo*sin(kx)*cos(wt)" Hecht says the standing wave "profile does not move through space". I have said the RF standing wave current profile does not move through a wire. Hecht says the standing wave phasor "doesn't rotate at all, and the resultant wave it represents doesn't progress through space - it's a standing wave." I have said the same thing about the RF standing wave current phasor. Hecht says the standing wave transfers zero net energy. I have said the same thing about RF standing waves. -- 73, Cecil http://www.qsl.net/w5dxp |
#5
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Cecil Moore wrote:
Tom Donaly wrote: Whatever. I'd still like to see his derivations. "Optics", by Hecht, 4th edition, page 289. The intensity of a light beam is associated with the E-field so Hecht's equations are in relation to the E-field. Speaking of the light standing wave: "The composite disturbance is then: E = Eo[sin(kt+wt) + sin(kt-wt)] Applying the indentity sin A + sin B = 2 sin 1/2(A+B)*cos 1/2(A-B) E(x,t) = 2*Eo*sin(kx)*cos(wt)" Hecht says the standing wave "profile does not move through space". I have said the RF standing wave current profile does not move through a wire. Hecht says the standing wave phasor "doesn't rotate at all, and the resultant wave it represents doesn't progress through space - it's a standing wave." I have said the same thing about the RF standing wave current phasor. Hecht says the standing wave transfers zero net energy. I have said the same thing about RF standing waves. If it's a solution to the wave equation it's o.k., Cecil, but Hecht is still not using the case where there is a phase difference between the two waves. If it isn't in the original equation it won't be in the final version since they're just two ways of saying the same thing. That's fine because it's the wrong equation anyway for what you want, which involves impedances and length, which you probably don't want to deal with because you're probably under the impression they're just virtual and not real, and so not worthy of inclusion in your theory. 73, Tom Donaly, KA6RUH |
#6
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Tom Donaly wrote:
If it's a solution to the wave equation it's o.k., Cecil, but Hecht is still not using the case where there is a phase difference between the two waves. Yes, he is, Tom. The phase *disappears* when you add the two traveling waves. That you don't recognize that fact of physics is the source of your misconception. The forward and reflected wave phasors are rotating in opposite directions at the same angular velocity. That makes their sum a constant phase value for half the cycle and the opposite constant phase value for the other half of the cycle. I and Richard Harrison have already explained that a number of times quoting Kraus and Terman. Here are a number of problems. I(f) is forward current and I(r) is reflected current. Please everybody, perform the following phasor additions where I(f)+I(r) is the *standing wave current*: I(f) I(r) I(f)+I(r) 1 amp at 0 deg 1 amp at 0 deg _________________ 1 amp at -30 deg 1 amp at +30 deg _________________ 1 amp at -60 deg 1 amp at +60 deg _________________ 1 amp at -90 deg 1 amp at +90 deg _________________ 1 amp at -120 deg 1 amp at +120 deg _________________ 1 amp at -150 deg 1 amp at +150 deg _________________ 1 amp at -180 deg 1 amp at +180 deg _________________ If you guys will take pen to paper and fill in those blanks you will uncover the misconception that has haunted this newsgroup for many weeks. If you need help with the math, feel free to ask for help. -- 73, Cecil http://www.qsl.net/w5dxp |
#7
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Cecil Moore wrote:
(snip) Here are a number of problems. I(f) is forward current and I(r) is reflected current. Please everybody, perform the following phasor additions where I(f)+I(r) is the *standing wave current*: I(f) I(r) I(f)+I(r) 1 amp at 0 deg 1 amp at 0 deg 2 A @ 0 deg 1 amp at -30 deg 1 amp at +30 deg 1.72 A @ 0 deg 1 amp at -60 deg 1 amp at +60 deg 1 A @ 0 deg 1 amp at -90 deg 1 amp at +90 deg 0 A @ 0 deg 1 amp at -120 deg 1 amp at +120 deg 1 A @ 180 deg 1 amp at -150 deg 1 amp at +150 deg 1.72 A @ 180 deg 1 amp at -180 deg 1 amp at +180 deg 2 A @ 180 deg If you guys will take pen to paper and fill in those blanks you will uncover the misconception that has haunted this newsgroup for many weeks. If you need help with the math, feel free to ask for help. What misconception? That all current in a standing wave has the same phase, rather than one of two possible phases? |
#8
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Cecil Moore wrote:
Tom Donaly wrote: If it's a solution to the wave equation it's o.k., Cecil, but Hecht is still not using the case where there is a phase difference between the two waves. Yes, he is, Tom. The phase *disappears* when you add the two traveling waves. That you don't recognize that fact of physics is the source of your misconception. The forward and reflected wave phasors are rotating in opposite directions at the same angular velocity. That makes their sum a constant phase value for half the cycle and the opposite constant phase value for the other half of the cycle. I and Richard Harrison have already explained that a number of times quoting Kraus and Terman. Here are a number of problems. I(f) is forward current and I(r) is reflected current. Please everybody, perform the following phasor additions where I(f)+I(r) is the *standing wave current*: I(f) I(r) I(f)+I(r) 1 amp at 0 deg 1 amp at 0 deg _________________ 1 amp at -30 deg 1 amp at +30 deg _________________ 1 amp at -60 deg 1 amp at +60 deg _________________ 1 amp at -90 deg 1 amp at +90 deg _________________ 1 amp at -120 deg 1 amp at +120 deg _________________ 1 amp at -150 deg 1 amp at +150 deg _________________ 1 amp at -180 deg 1 amp at +180 deg _________________ If you guys will take pen to paper and fill in those blanks you will uncover the misconception that has haunted this newsgroup for many weeks. If you need help with the math, feel free to ask for help. Cecil, if you don't put any phase information in your original formula it won't be there when you say the same thing some other way. But if you do put it in there, then it has to affect both formulas. If it disappears, you've done something wrong. If you and Harrison can't figure out how to extract phase information from a standing wave you should return your diplomas to wherever you got them from. 73, Tom Donaly, KA6RUH (P.S. Let me give you a hint: first you have to find out what phase means in a standing wave on a transmission line. You probably already think you know, though, so I don't expect you to bother much about it.) |
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