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Current through coils
Dave wrote:
I thought there is/was a restriction that "Everything" must include "a significant portion of a wavelength". :-) A lumped-circuit inductance is *NEVER* a significant portion of a wavelength, by definition and presupposition. That's the argument being put forth by the lumped-circuit gurus. :-) -- 73, Cecil http://www.qsl.net/w5dxp |
Current through coils
Tom Donaly wrote:
You're right, not strange at all. In his posting, Richard C. proved he doesn't know how to turn on the 'Current Phase' option in EZNEC, proved he cannot use a formula to extract a valid calculation, proved he doesn't know how to add phase angles, and you are agreeing with him? And you accuse me of not understanding what I read? -- 73, Cecil http://www.qsl.net/w5dxp |
Current through coils
Richard Clark wrote:
Cecil Moore wrote: I said something about +/- 50% accuracy. The linear delay calculation is off by 59%, not too far from my 50% rough estimate. error is growing faster than the national debt. ;-) Now, that is certainly a lie. :-) Remember, W8JI said that any answer is better than no answer. That presumably includes his wrong answers. :-) Stretching your tolerance for error to fit your argument can lead to any conclusion. It's not a tolerance for error. It's a recognition that the answer is, so far, unknown. I've said it befo The delay through the coil is what it is and we don't know exactly what it is. That it is difficult to estimate or measure has absolutely no effect on its value in reality. What we know for sure is that the presuppositions of the lumped-circuit model indeed do violate the laws of physics. Faster than light propagation through a coil comes to mind. I am admittedly surprised to see the velocity factor fall so rapidly with frequency. My surprise has absolutely no effect on reality. I just use the scientific method to adjust my concepts and move on. However, to paraphrase an old TV commercial, "It's not nice to fool Father Guru". The earth may reduce to a quantum singularity when the r.r.a.a gurus recognize their errors. :-) -- 73, Cecil http://www.qsl.net/w5dxp |
Current through coils
John Popelish wrote:
Not if the lumped inductor model includes lumps of capacitance that represent the strays to ground. Lumped LC networks exhibit phase shift, also. But please remember the original assertions by the gurus. There is ZERO phase shift through an inductor. There is ZERO amplitude change through an inductor. This can easily be proven by observing the lumped inductances in EZNEC. W7EL shot down those arguments by installing the helix feature in EZNEC. :-) Never blame malice when ignorance will suffice. If this person has to confess between ignorance and malicious behavior, I am sure he would go to jail rather than admit any ignorance. -- 73, Cecil http://www.qsl.net/w5dxp |
Current through coils
I thought there is/was a restriction that "Everything" must include "a significant portion of a wavelength". =================================== There are no problems. A very short coil behaves as a very short transmission line. ---- Reg. |
Current through coils
Reg is correct. Even a very short structure, much shorter than a
wavelength, acts like a transmission line. A short structure just acts like a short transmission line. It's just that if it's short, there are simpler ways to analyze it which will get us essentially the same answer. But we can use full blown transmission line analysis on any structure if we choose, and should get the correct answer. Roy Lewallen, W7EL Dave wrote: EVERYTHING???? I thought there is/was a restriction that "Everything" must include "a significant portion of a wavelength". :-) Reg Edwards wrote: EVERYTHING has Inductance, Capacitance and Resistance, and therefore behaves as a transmission line. ---- Reg, G4FGQ |
Current through coils
Cecil Moore wrote:
5.5 MHz: 14.1 deg, 5.89 MHz: 15.7 deg, 6 MHz: 16.2 deg, 7 MHz: 21.4 deg, 8 MHz: 29.5 deg, 9 MHz: 45.9 deg, 10 MHz: 89 deg, 11 MHz: 141.4 deg, 12 MHz: 163.0 deg, 13 MHz: 172.3 deg, 13.7 MHz: 183.82 deg. I just bought Mathcad and am trying to learn to use it. The graph of the above data is really interesting. Somewhat like a sine function, this curve has an inflection point around 10 MHz where the phase shift is changing most rapidly. On either side of 10 MHz, it doesn't change as rapidly. 10 MHz appears to be the 1/8 wavelength point where |Z0| = |XL|. -- 73, Cecil http://www.qsl.net/w5dxp |
Current through coils
Reg Edwards wrote:
I thought there is/was a restriction that "Everything" must include "a significant portion of a wavelength". =================================== There are no problems. A very short coil behaves as a very short transmission line. ---- Reg. I'm glad to know that I can substitute a coil of wire every time I need a transmission line. So tell me, Reg, what are the specs on the coil I'd need to make a transmission line transformer to match 75 ohms to 325.33 ohms? 73, Tom Donaly, KA6RUH |
Current through coils
Cecil Moore wrote:
Tom Donaly wrote: You're right, not strange at all. In his posting, Richard C. proved he doesn't know how to turn on the 'Current Phase' option in EZNEC, proved he cannot use a formula to extract a valid calculation, proved he doesn't know how to add phase angles, and you are agreeing with him? And you accuse me of not understanding what I read? What about figure 2, Cecil? 73, Tom Donaly, KA6RUH |
Current through coils
Roy Lewallen wrote:
Reg is correct. Even a very short structure, much shorter than a wavelength, acts like a transmission line. A short structure just acts like a short transmission line. It's just that if it's short, there are simpler ways to analyze it which will get us essentially the same answer. But we can use full blown transmission line analysis on any structure if we choose, and should get the correct answer. Seems that you agree that the distributed network model works for all common problems. That makes sense since the distributed network model is a superset of the lumped-circuit model. Using Dr. Corum's rule that models should be switched at 15 degrees, 15 degrees of a 450 ohm transmission line will transform 50+j0 ohms to 54+j120 ohms. The difference in 50 ohm SWR is 7:1 Vs 1:1. That seems like a pretty large error to me just to be able to stick with the lumped-circuit model. -- 73, Cecil http://www.qsl.net/w5dxp |
Current through coils
Reg Edwards wrote:
I thought there is/was a restriction that "Everything" must include "a significant portion of a wavelength". =================================== There are no problems. A very short coil behaves as a very short transmission line. ---- Reg. C'mon Reg! We both know that a 1/4 inch diameter loop is NOT a transmission line at 0.1 MHz. :-0 |
Current through coils
Tom Donaly wrote:
I'm glad to know that I can substitute a coil of wire every time I need a transmission line. So tell me, Reg, what are the specs on the coil I'd need to make a transmission line transformer to match 75 ohms to 325.33 ohms? How about at least tell Reg the frequency? -- 73, Cecil http://www.qsl.net/w5dxp |
Current through coils
Tom Donaly wrote:
What about figure 2, Cecil? Figure 2 suggests that any coil with a delay over 15 degrees should be analyzed by discarding the lumped circuit model and instead using the distributed network model. Every coil I have talked about on this thread has a delay greater than 15 degrees. 15 degrees of impedance transformation will transform 50 ohms into 54+j120 ohms with a difference in SWRs of 7 to one. Does that really sound like a reasonable reason for keeping the lumped-circuit model? Roy just said in another posting that the reflection model will solve all the problems that the lumped circuit model will solve. It just gets clumsy as far as the math goes. It is interesting to watch the gurus retreat into fantasy where they were only ever talking about tiny point inductances to start with. Anyone who has been following this argument over the years knows otherwise. -- 73, Cecil http://www.qsl.net/w5dxp |
Current through coils
Cecil Moore wrote:
Tom Donaly wrote: I'm glad to know that I can substitute a coil of wire every time I need a transmission line. So tell me, Reg, what are the specs on the coil I'd need to make a transmission line transformer to match 75 ohms to 325.33 ohms? How about at least tell Reg the frequency? Reg is old enough to pick his own frequency. 73, Tom Donaly, KA6RUH |
Current through coils
I'm glad to know that I can substitute a coil of wire every time I need a transmission line. So tell me, Reg, what are the specs on the coil I'd need to make a transmission line transformer to match 75 ohms to 325.33 ohms? 73, Tom Donaly, KA6RUH ======================================= Every coil is a transmission line. But not every transmission line is a coil. ---- Reg. |
Current through coils
Cecil Moore wrote:
Tom Donaly wrote: What about figure 2, Cecil? Figure 2 suggests that any coil with a delay over 15 degrees should be analyzed by discarding the lumped circuit model and instead using the distributed network model. Every coil I have talked about on this thread has a delay greater than 15 degrees. 15 degrees of impedance transformation will transform 50 ohms into 54+j120 ohms with a difference in SWRs of 7 to one. Does that really sound like a reasonable reason for keeping the lumped-circuit model? Roy just said in another posting that the reflection model will solve all the problems that the lumped circuit model will solve. It just gets clumsy as far as the math goes. It is interesting to watch the gurus retreat into fantasy where they were only ever talking about tiny point inductances to start with. Anyone who has been following this argument over the years knows otherwise. Figure 2 shows that the authors considered their model to be that of a shorted stub to replace the inductance of their Tesla coil. They didn't say that a coil of wire is a shorted stub, only that it performs the same function as one in the calculations. You're waffling and trying to slick your way out of an embarrassing situation again, Cecil. O.k., I'll accept the shorted stub substitution. Heck, I'll even accept a solution involving op-amps, (provided you don't use it in transmit mode). What I won't accept is pretending a long hank of transmission line with a load at one end performs the same impedance transformation in the same way as a coil of wire. 73, Tom Donaly, KA6RUH |
Current through coils
Roy Lewallen wrote:
Reg is correct. Even a very short structure, much shorter than a wavelength, acts like a transmission line. A short structure just acts like a short transmission line. It's just that if it's short, there are simpler ways to analyze it which will get us essentially the same answer. But we can use full blown transmission line analysis on any structure if we choose, and should get the correct answer. Roy Lewallen, W7EL Dave wrote: EVERYTHING???? I thought there is/was a restriction that "Everything" must include "a significant portion of a wavelength". :-) Reg Edwards wrote: EVERYTHING has Inductance, Capacitance and Resistance, and therefore behaves as a transmission line. ---- Reg, G4FGQ If we do, we're going to have our work cut out for us. When the fundamental quantities L, R, C, and G are unknown functions instead of constants, analysis gets tricky. If it didn't get tricky, we could solve for currents on conductors with simple equations instead of having to use moment methods to numerically solve intractible integral equations. 73, Tom Donaly, KA6RUH |
Current through coils
Tom Donaly wrote:
You're waffling and trying to slick your way out of an embarrassing situation again, Cecil. I sincerely do not know what you are babbling about. I'm not aware that I am in an embarrassing situation and if I were aware, I would ask someone to enlighten me. I have read Dr. Corum's articles multiple times and understand more and more each time I read them. I am using the scientific method to correct my mistakes and move on. What are you doing? Mounting ad hominem waffling and slicking attacks. -- 73, Cecil http://www.qsl.net/w5dxp |
Current through coils
Tom Donaly wrote:
Cecil Moore wrote: Roy just said in another posting that the reflection model will solve all the problems that the lumped circuit model will solve. It just gets clumsy as far as the math goes. . . . I said "transmission line" model, not "reflection" model. I want to clarify this because I don't want what I said to be interpreted as an endorsement of Cecil's alternate theories involving traveling waves. Implicit in what I said is also that the transmission line model or equations must be used correctly. Roy Lewallen, W7EL |
Current through coils
Roy Lewallen wrote:
Cecil Moore wrote: Roy just said in another posting that the reflection model will solve all the problems that the lumped circuit model will solve. It just gets clumsy as far as the math goes. I said "transmission line" model, not "reflection" model. I want to clarify this because I don't want what I said to be interpreted as an endorsement of Cecil's alternate theories involving traveling waves. Implicit in what I said is also that the transmission line model or equations must be used correctly. What's the difference between the transmission line model and the reflection model? -- 73, Cecil http://www.qsl.net/w5dxp |
Current through coils
What's the difference between the transmission line model and
the reflection model? -- 73, Cecil ======================================= No difference whatsoever - except that Cecil is obsessed with reflections and he worships some guy named Corum. ;o) ---- Reg. |
Current through coils
On Sun, 26 Mar 2006 18:03:26 GMT, Cecil Moore
wrote: Don't you know how to turn on the 'Current Phase' option when displaying EZNEC results. Do you need a tutorial? This is YOUR work, not mine, thus it is YOUR problem, not mine. Trying to add those phases shows a lot of ignorance. Ah! Leading with your chin again. 3. The coil Vf shown on the web is 0.1375 is different than eq (32) = 0.0078 Sorry, you're wrong. eq(32) for this coil yields a VF of ~0.033 Can't do the math? Twice? which Dr. Corum claims to be accurate within about 10%. 10% 50% 59%? and now we're down to "pick a number, any number" 4. refuting your own references (Corum²). Dr. Corum's equation for the coil VF is at its *SELF-RESONANT* frequency, not anywhere else. Using it anywhere else is only a *VERY ROUGH* estimate. At the self resonant frequency reported by EZNEC, the VF calculates out to be ~0.055. Thank you for making my point. and the answer remains: Strange? No, 4 out of 4 stand as an amusing footnote. |
Current through coils
On Sun, 26 Mar 2006 18:04:56 GMT, "Tom Donaly"
wrote: Cecil never actually reads his references Hi Tom, The legacy of conducting research by Xerox. 73's Richard Clark, KB7QHC |
Current through coils
Reg Edwards wrote:
I'm glad to know that I can substitute a coil of wire every time I need a transmission line. So tell me, Reg, what are the specs on the coil I'd need to make a transmission line transformer to match 75 ohms to 325.33 ohms? 73, Tom Donaly, KA6RUH ======================================= Every coil is a transmission line. But not every transmission line is a coil. ---- Reg. An answer worthy of a zen master. If you keep this up, Reg, we'll all be cursed with enlightenment. 73, Tom Donaly, KA6RUH |
Current through coils
On Sun, 26 Mar 2006 19:14:36 GMT, Cecil Moore
wrote: I've said it befo The delay through the coil is what it is and we don't know exactly what it is. Is Popeye Descartes your latest personality? |
Current through coils
On Sun, 26 Mar 2006 22:16:57 +0100, "Reg Edwards"
wrote: Every coil is a transmission line. But not every transmission line is a coil. Looks like a zen worm has spam infected newsgroupspace. |
Current through coils
Tom Donaly wrote:
An answer worthy of a zen master. If you keep this up, Reg, we'll all be cursed with enlightenment. 73, Tom Donaly, KA6RUH Funny you should say that. Made me think of the (not really correct) "zen archery" philosophy of defining the target as being wherever the arrow strikes. So the arrow always hits the target. In reading this thread I find that line of reasoning familiar. Roy Lewallen, W7EL |
Current through coils
Richard Clark wrote:
Cecil Moore wrote: Don't you know how to turn on the 'Current Phase' option when displaying EZNEC results. Do you need a tutorial? This is YOUR work, not mine, thus it is YOUR problem, not mine. It's my problem that you don't know how to turn on the 'Current Phase' option in EZNEC??? Just how do you propose that I gain control over your computer? It states on the graphic that the 'Current Phase' option is 'ON'. Trying to add those phases shows a lot of ignorance. Ah! Leading with your chin again. If you are really into adding up phase angles, then add them up every inch. You will approach infinity as the sum. Your approach is a lot like adding up power every inch and declaring the transmission lines contains eighteen gigawatts of power. -- 73, Cecil http://www.qsl.net/w5dxp |
Current through coils
It appears that Cecil is back with many postings, but he seems to be
ignoring answering my question. Perhaps he's unable to do so. Just so the lurkers understand that indeed it is possible to work through the phasor math, here goes. Here's exactly the scenario Cecil set up, quoted from his posting: ========== "So to be perfectly clear, here is my statement re-worded using a 45 degree phase shift through the coil. The forward current magnitude is equal at both ends of the coil. The reflected current magnitude is equal at both ends of the coil. At the bottom of the coil, the forward current is 1 amp at zero deg. At the bottom of the coil, the reflected current is 1 amp at zero deg. At the bottom of the coil, the standing wave current is 2 amps at zero deg. At the top of the coil, the forward current is 1 amp at -45 deg. At the top of the coil, the reflected current is 1 amp at +45 deg. At the bottom of the coil, the standing wave current is 1.4 amp at zero deg." ========== OK, so the difference in "FORWARD" current from the bottom to the top is: fwd.bottom.current - fwd.top.current = 1A at 0 degrees - 1 amp at -45 degrees = 1+j0 - sqrt(.5)-j*sqrt(.5) = 1-sqrt(.5) + j*sqrt(.5) (about 0.765 at 67.5 degrees) The difference in "REFLECTED" current from the bottom to the top is: refl.bottom.current - refl.top.current = 1A at 0 degrees - 1 amp at +45 degrees = 1+j0 - sqrt(.5)-j*sqrt(.5) = 1-sqrt(.5) - j*sqrt(.5) The SUM of these two differences is: [1-sqrt(.5) + j*sqrt(.5)] + [1-sqrt(.5) - j*sqrt(.5)] = 2 - 2*sqrt(.5) + j0 = 2 - sqrt(2) + j0 = 2 - sqrt(2) at zero degrees The standing wave current at the bottom of the coil is 2 amps just as Cecil suggests at one point: It's the sum of the "forward" and "reflected": net current at the bottom = sw.bottom.current = 1+j0 + 1+j0 = 2+j0 = 2 at zero degrees Presumably Cecil meant that the standing wave current at the TOP (not the BOTTOM) of the coil is 1.4 amps at 0 degrees. That's close, but more exactly, it's net current at the top = sw.top.current = sqrt(.5)-j*sqrt(.5) = sqrt(.5)+j*sqrt(.5) = 2*sqrt(.5) = sqrt(2) = sqrt(2) at zero degrees. So the difference in net current (that is, the difference in the standing wave current) between the top and the bottom of the coil in this example is exactly: sw.bottom.current - sw.top.current = 2 at zero degrees - sqrt(2) at zero degrees = 2 - sqrt(2) at zero degrees So, we see that the difference in current between the bottom and the top is exactly the same, independent of whether we just use the standing-wave currents, or the currents in the "forward" travelling wave plus the currents in the "reflected" wave. That it's also exactly the same answer you get by looking at a full cycle of instantaneous currents is left as an exercise (fairly simple) for the reader. Either way, there is a difference, and that current must go somewhere. It should be pretty easy to account for it. In fact, it's not even very hard to predict fairly accurately in the case of a loading coil in an antenna perpendicular to a ground plane or equivalently in a symmetrical doublet. Cheers, Tom |
Current through coils
Cecil Moore wrote:
(snip) Here's what EZNEC reports as the phase shift through the coil in the traveling wave antenna previously tested at 5.89 MHz. 5.5 MHz: 14.1 deg, 5.89 MHz: 15.7 deg, 6 MHz: 16.2 deg, 7 MHz: 21.4 deg, 8 MHz: 29.5 deg, 9 MHz: 45.9 deg, 10 MHz: 89 deg, 11 MHz: 141.4 deg, 12 MHz: 163.0 deg, 13 MHz: 172.3 deg, 13.7 MHz: 183.82 deg. Here is that list repeated in units of time, instead of degrees: MHz ns delay 5.5 7.1 5.89 7.4 6 7.5 7 8.5 8 10.2 9 14.2 10 24.7 11 35.7 12 37.7 13 36.8 13.7 37.3 I would have to graph this on a log frequency plot to see the frequency breakpoints, but I think this looks a lot like a short piece of transmission line below about 6 MHz and like a resonator above that. I expect the delay to start to fall at higher frequencies as the turn-to-turn capacitance takes over. What do you see? |
Current through coils
K7ITM wrote:
OK, so the difference in "FORWARD" current from the bottom to the top is: fwd.bottom.current - fwd.top.current = 1A at 0 degrees - 1 amp at -45 degrees = 1+j0 - sqrt(.5)-j*sqrt(.5) = 1-sqrt(.5) + j*sqrt(.5) (about 0.765 at 67.5 degrees) That is truly magic. Someone must have slept through class that day. Good grief! You can't subtract two currents that are a foot apart from each other. Currents superpose at a point. Currents from each end of the coil a foot apart don't superpose. They don't even know each other exist. Good Grief! Ifor=1A at 0 deg Ifor=1A at -45 deg -----------------X-/////////-Y------------------ Iref=1A at 0 deg Iref=1A at +45 deg The forward current superposes with the reflected current at the bottom of the coil to get 2 amps at zero degrees. The forward current superposes with the reflected current at the top of the coil to get 1.4 amps at zero degrees. The delay through the coil is 45 degrees. Neglecting losses: The energy in the forward wave is the same at the top and bottom of the coil. The energy in the reflected wave is the same at the top and bottom of the coil. There is zero net steady-state energy storage between the top and bottom of the coil. There's no RF battery there. -- 73, Cecil http://www.qsl.net/w5dxp |
Current through coils
On Sun, 26 Mar 2006 23:46:00 GMT, Cecil Moore
wrote: Trying to add those phases shows a lot of ignorance. Ah! Leading with your chin again. If you are really into adding up phase angles, then add them up every inch. Still leading with your chin? Amazing how you dismiss the "important" stuff with ±59% but want to add every inch. Why would ANYONE do what you suggest in the face of your outright sloppy work? |
Current through coils
John Popelish wrote:
I would have to graph this on a log frequency plot to see the frequency breakpoints, but I think this looks a lot like a short piece of transmission line below about 6 MHz and like a resonator above that. I expect the delay to start to fall at higher frequencies as the turn-to-turn capacitance takes over. What do you see? I see something that resembles part of a sine wave with a point of inflection (resembling a zero crossing) around 10 MHz. The phase shift around 10 MHz is 60 degrees per MHz. The phase shift above and below 10 Mhz is lower. I sure can see why the lumped circuit model is a total and complete failure when applied at 10 MHz. I also can see why Dr. Corum chose 15 degrees as his cutoff point. -- 73, Cecil http://www.qsl.net/w5dxp |
Current through coils
On Mon, 27 Mar 2006 01:04:43 GMT, Cecil Moore
wrote: Columbus is famous for missing by 10,000 miles appeal to antiquity to grant 4 orders of magnitude slop, hmmm? Columbus was an Italian huckster who was pitching sloppy math to make himself look authoritative. At least we've found a convergence there. My 60% accuracy is a heck of a lot more accurate than An error of 50, 59 now 60% is not 60% accuracy and given: On Sun, 26 Mar 2006 19:14:36 GMT, Cecil Moore wrote: I've said it befo The delay through the coil is what it is and we don't know exactly what it is. To say the delay is unknown, but you are 60% accurate is one for warranting a dope slap from Lord Kelvinator. |
Current through coils
Sorry you've missed the point, Cecil. I can only hope the lurkers get
it. (Aside: I'm not exactly sure what you mean by "no net steady-state energy storage." If that's true, then there's never ANY current in the inductor, because the energy stored in an inductor's magnetic field is i^2*L/2, and that's always positive for non-zero i.) Cheers, Tom |
Current through coils
You are leading yourselves astray again.
Anything which produces a velocity factor which varies significantly with frequency is INCORRECT. The propagation delay (in nano-seconds) along a coil is a constant and is independent of frequency. It depends only on the physical dimensions of the coil, ie., on L and C, which are fixed in a given situation. This is just the same as on an ordinary transmission line. ---- Reg. |
Current through coils
A bit more on this...
I trust it's an accurate summary to say that Cecil gave us the "forward" and "reflected" currents at both ends of a coil, and correctly deduced the standing-wave currents at each end from those. But given that information, Cecil is unable (and believes it is impossible) to determine the net charge in the volume containing the coil as a function of time (to within a constant, at least), even though the the wires in which we know the currents are the only way for charge to get in and out of that volume. I do hope we can at least agree that current is the rate at which charge passes a point... And I do hope most folk tuned in here don't have so much trouble with it. Farewell, goodbye, auf wiedersehen, adieu... Tom Cecil wrote: "K7ITM wrote: OK, so the difference in "FORWARD" current from the bottom to the top is: fwd.bottom.current - fwd.top.current = 1A at 0 degrees - 1 amp at -45 degrees = 1+j0 - sqrt(.5)-j*sqrt(.5) = 1-sqrt(.5) + j*sqrt(.5) (about 0.765 at 67.5 degrees) That is truly magic. Someone must have slept through class that day. Good grief! You can't subtract two currents that are a foot apart from each other. Currents superpose at a point. Currents from each end of the coil a foot apart don't superpose. They don't even know each other exist. Good Grief! Ifor=1A at 0 deg Ifor=1A at -45 deg -----------------X-/////////-Y------------------ Iref=1A at 0 deg Iref=1A at +45 deg The forward current superposes with the reflected current at the bottom of the coil to get 2 amps at zero degrees. The forward current superposes with the reflected current at the top of the coil to get 1.4 amps at zero degrees. The delay through the coil is 45 degrees. Neglecting losses: The energy in the forward wave is the same at the top and bottom of the coil. The energy in the reflected wave is the same at the top and bottom of the coil. There is zero net steady-state energy storage between the top and bottom of the coil. There's no RF battery there. -- 73, Cecil http://www.qsl.net/w5dxp " |
Current through coils
Reg Edwards wrote:
The propagation delay (in nano-seconds) along a coil is a constant and is independent of frequency. MOM seems to disagree. -- 73, Cecil http://www.qsl.net/w5dxp |
Current through coils
K7ITM wrote:
Sorry you've missed the point, Cecil. I can only hope the lurkers get it. If the lurkers think one can add or subtract the forward current at both ends of the coils, as you did, I feel sorry for them. -- 73, Cecil http://www.qsl.net/w5dxp |
Current through coils
K7ITM wrote:
Cecil is unable (and believes it is impossible) to determine the net charge in the volume containing the coil as a function of time (to within a constant, at least), even though the the wires in which we know the currents are the only way for charge to get in and out of that volume. THERE IS NO RF BATTERY STORING ENERGY! THERE IS ZERO LONG TERM ACCUMULATION OF CHARGE! Neglecting losses, energy in exactly equals energy out over the long term. The fact that 2 amps of standing wave current exists at the bottom of the coil and 1.4 amps of standing wave current exists at the top of the coil doesn't imply any long term accumulation of charge. Long term accumulation of charge in a coil is impossible. -- 73, Cecil http://www.qsl.net/w5dxp |
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