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Current across the antenna loading coil - from scratch
K7ITM wrote:
Yes, some time earlier today than that exchange, I posted elsewhere in this thread a specific circuit, complete with values, how the same thing is easily accomplished with the infamous ideal lumped components. No standing waves need apply. But of course if one used distributed reactances, one could easily get the same effect, and the analysis can easily be done w/o any reference to standing or travelling waves. How about the phase shift? -- 73, Cecil http://www.qsl.net/w5dxp |
Current across the antenna loading coil - from scratch
Gene Fuller wrote:
I gave you a very specific reference to demonstrate your supposition was incorrect. You came back with nothing but, "Because I say so." You have not offered one shred of backing for your constant Vf argument. Where the heck have you been? The equation for VF is equation (32) at: http://www.ttr.com/TELSIKS2001-MASTER-1.pdf Just before that equation for VF is a geometry test for the coil in question. A 75m bugcatcher coil passes that test. The velocity factor equation contains helix diameter, turns per unit length, and wavelength. If we keep those three quantities constant, the VF of a coil should remain constant while varying the length of the coil. The problem encountered previously was we kept the coil length constant while varying the frequency. That does change the VF. But this time we are keeping frequency constant. -- 73, Cecil http://www.qsl.net/w5dxp |
Current across the antenna loading coil - from scratch
Cecil,
Why don't you go back and re-read that paper carefully. Pay particular attention to the part where the author says, with emphasis, that the magic formula only works when the coil is near or at resonance. Your extension to arbitrarily lower frequencies is pure nonsense. I guess you did not read my complete message. I pointed out the exact location in the paper where this limitation is explained. 73, Gene W4SZ Cecil Moore wrote: Gene Fuller wrote: I gave you a very specific reference to demonstrate your supposition was incorrect. You came back with nothing but, "Because I say so." You have not offered one shred of backing for your constant Vf argument. Where the heck have you been? The equation for VF is equation (32) at: http://www.ttr.com/TELSIKS2001-MASTER-1.pdf Just before that equation for VF is a geometry test for the coil in question. A 75m bugcatcher coil passes that test. The velocity factor equation contains helix diameter, turns per unit length, and wavelength. If we keep those three quantities constant, the VF of a coil should remain constant while varying the length of the coil. The problem encountered previously was we kept the coil length constant while varying the frequency. That does change the VF. But this time we are keeping frequency constant. |
Current across the antenna loading coil - from scratch
Gene Fuller wrote:
Why don't you go back and re-read that paper carefully. Pay particular attention to the part where the author says, with emphasis, that the magic formula only works when the coil is near or at resonance. A 75m bugcatcher coil is self resonant at 6.6 MHz. That's near 4 MHz. Where is all your irrationality coming from? -- 73, Cecil http://www.qsl.net/w5dxp |
Current across the antenna loading coil - from scratch
Cecil Moore wrote:
Gene Fuller wrote: Why don't you go back and re-read that paper carefully. Pay particular attention to the part where the author says, with emphasis, that the magic formula only works when the coil is near or at resonance. A 75m bugcatcher coil is self resonant at 6.6 MHz. That's near 4 MHz. Where is all your irrationality coming from? 4 Mhz is not 6.6 Mhz. You're stretching the truth again, Cecil. Gene is right. Why not just give up. You're not going to make anything true just by repeating it over and over again. 73, Tom Donaly, KA6RUH |
Current across the antenna loading coil - from scratch
Cecil Moore wrote:
Gene Fuller wrote: Why don't you go back and re-read that paper carefully. Pay particular attention to the part where the author says, with emphasis, that the magic formula only works when the coil is near or at resonance. A 75m bugcatcher coil is self resonant at 6.6 MHz. That's near 4 MHz. Where is all your irrationality coming from? Cecil, I guess you can't keep up with your fairy tales. The exact quote from your message on April 11, at 9:57 am is copied below. I don't see anything about a bugcatcher coil. Instead there is some un-described coil stock that requires 37 extra turns in addition to the starting 32 turns to achieve self-resonance at 4 MHz. Since the Corum paper highlighted the limitation for applicability of the magic formula it is possible he thought that the limitation might be important. However, with your superior intellect it is fully justifiable to go ahead and accept only those portions of his paper that support your preconceived notions. I suppose whatever number you determine will still fall within your 59% standard of precision. 73, Gene W4SZ [quote] ************************************************** * Here's a more valid procedure for determining the delay through a coil. Changing nothing except the number of turns, add turns until the coil is self- resonant at the frequency of use. Frequency doesn't change. Coil diameter doesn't change. Turns per inch doesn't change. The *ONLY* thing that changes is the length of the coil. At self-resonance, we *know* the longer coil is 90 degrees long. ************************************************** * Take that same 32 turn coil and keeping everything the same, add turns to the coil until it is self-resonant. We haven't changed the frequency, the diameter, or the turns per inch. All we have done is add 37 turns to the original 32 turn coil to make the self-resonant frequency equal to 4 MHz with 69 turns. SINCE WE HAVEN'T CHANGED THE FREQUENCY, WE KNOW THAT THE VELOCITY FACTOR OF THE COIL HAS NOT CHANGED. In the velocity factor equation, the only variables are coil diameter, turns per inch, and wavelength. NONE OF THOSE VARIABLES ARE CHANGED ABOVE. So we know that 69 turns makes that coil stock self-resonant at 4 MHz. That would make the phase shift through 32 turns equal to 42 degrees, making our above 10 degree assumption false. 42 degrees is probably fairly close to the actual value. The velocity factor for that coil stock calculates out to be 0.023 on 4 MHz. [end quote] |
Current across the antenna loading coil - from scratch
Tom Donaly wrote:
4 Mhz is not 6.6 Mhz. Nobody said 4 MHz is 6.6 MHz. 4 MHz is 60% of 6.6 MHz and is therefore near 6.6 MHz. Dr. Corum says the lumped constant model fails at 0.04 wavelength. In his other paper, he says if the length of the wire used to wind the coil is 0.06 wavelength, it's time to switch over to the distributed network model. A 75m bugcatcher coil uses more than 0.06 wavelength of wire. Please explain the physics behind the velocity factor of a coil changing radically just because you cut it in half - assuming all other parameters are kept at the same value. Your model is known to fail at a point but you guys have no clue where that failure point is. You just have faith that you will never reach the failure point. But what if you have already reached it? -- 73, Cecil http://www.qsl.net/w5dxp |
Current across the antenna loading coil - from scratch
Gene Fuller wrote:
Cecil Moore wrote: A 75m bugcatcher coil is self resonant at 6.6 MHz. That's near 4 MHz. Where is all your irrationality coming from? The exact quote from your message on April 11, at 9:57 am is copied below. I don't see anything about a bugcatcher coil. The coil being discussed is a bugcatcher coil modeled in EZNEC. Since the Corum paper highlighted the limitation for applicability of the magic formula it is possible he thought that the limitation might be important. The limitation that Dr. Corum highlighted was the failure of the lumped circuit model when the coil is self-resonant. He says that when we are within 17% of self-resonance, the lumped circuit model fails. Have you anything besides faith to prove that your model is valid within 60% of self-resonance? Please describe the physics behind a radical change in velocity factor (at the same frequency) when a coil is cut in half. -- 73, Cecil http://www.qsl.net/w5dxp |
Current across the antenna loading coil - from scratch
Cecil Moore wrote:
Gene Fuller wrote: Cecil Moore wrote: A 75m bugcatcher coil is self resonant at 6.6 MHz. That's near 4 MHz. Where is all your irrationality coming from? The exact quote from your message on April 11, at 9:57 am is copied below. I don't see anything about a bugcatcher coil. The coil being discussed is a bugcatcher coil modeled in EZNEC. Since the Corum paper highlighted the limitation for applicability of the magic formula it is possible he thought that the limitation might be important. The limitation that Dr. Corum highlighted was the failure of the lumped circuit model when the coil is self-resonant. He says that when we are within 17% of self-resonance, the lumped circuit model fails. Have you anything besides faith to prove that your model is valid within 60% of self-resonance? Please describe the physics behind a radical change in velocity factor (at the same frequency) when a coil is cut in half. Cecil, You have really lost it. I gave you the exact quote, and you then proceed to talk about something else. It appears you did not really read and understand the Corum paper either. The portion I referred to you had nothing to say about lumped circuits or distributed circuits. It was merely a step in the mathematical analysis that leads to the magic formula for Vf. If you ignore the important limitations on the math analysis it is likely that any conclusions drawn will be incorrect. So let's throw the topic back to you. A straight wire has a Vf near 1. A resonant coil has a Vf of 0.01 or 0.02. So where and how does the Vf transition occur? For a coil of one turn? For a coil with a length of 15% of the resonant length? At some other coil length? Is the Vf transition abrupt or smooth? You seem to understand everything about coil Vf, so these should be easy questions for you. 73, Gene W4SZ |
Current across the antenna loading coil - from scratch
"Cecil Moore" wrote in message . com... Gene Fuller wrote: Cecil Moore wrote: A 75m bugcatcher coil is self resonant at 6.6 MHz. That's near 4 MHz. Where is all your irrationality coming from? The exact quote from your message on April 11, at 9:57 am is copied below. I don't see anything about a bugcatcher coil. The coil being discussed is a bugcatcher coil modeled in EZNEC. Since the Corum paper highlighted the limitation for applicability of the magic formula it is possible he thought that the limitation might be important. The limitation that Dr. Corum highlighted was the failure of the lumped circuit model when the coil is self-resonant. He says that when we are within 17% of self-resonance, the lumped circuit model fails. Have you anything besides faith to prove that your model is valid within 60% of self-resonance? Please describe the physics behind a radical change in velocity factor (at the same frequency) when a coil is cut in half. -- ======================================== Dear Cec, What is the failure mode? Is it a sudden catastropic failure? Or does it fail very slowly, gradually and gently? What is Dr.Corum a doctor of? From your quotes he sounds like a Quack. Or is he a Witch? What does he have to say about Fractals, E-H and the other wierd contraptions? How many other worshipping followers does he have besides yourself? Or are you just pulling our varicose-veined legs? All rhetorical questions of course. Answers not required. ---- Your old, well-intentioned pal, Reg. |
Current across the antenna loading coil - from scratch
Reg Edwards wrote:
"Cecil Moore" wrote in message . com... Gene Fuller wrote: Cecil Moore wrote: A 75m bugcatcher coil is self resonant at 6.6 MHz. That's near 4 MHz. Where is all your irrationality coming from? The exact quote from your message on April 11, at 9:57 am is copied below. I don't see anything about a bugcatcher coil. The coil being discussed is a bugcatcher coil modeled in EZNEC. Since the Corum paper highlighted the limitation for applicability of the magic formula it is possible he thought that the limitation might be important. The limitation that Dr. Corum highlighted was the failure of the lumped circuit model when the coil is self-resonant. He says that when we are within 17% of self-resonance, the lumped circuit model fails. Have you anything besides faith to prove that your model is valid within 60% of self-resonance? Please describe the physics behind a radical change in velocity factor (at the same frequency) when a coil is cut in half. -- ======================================== Dear Cec, What is the failure mode? Is it a sudden catastropic failure? Or does it fail very slowly, gradually and gently? What is Dr.Corum a doctor of? From your quotes he sounds like a Quack. Or is he a Witch? What does he have to say about Fractals, E-H and the other wierd contraptions? How many other worshipping followers does he have besides yourself? Or are you just pulling our varicose-veined legs? All rhetorical questions of course. Answers not required. ---- Your old, well-intentioned pal, Reg. There are two Drs. Corum. Perhaps they're a husband-husband team. At any rate, they're Cecil clones, manufacturing a controversy out of thin air and fighting valiantly for it. 73, Tom Donaly, KA6RUH |
Current across the antenna loading coil - from scratch
Gene Fuller wrote:
You have really lost it. I gave you the exact quote, and you then proceed to talk about something else. Your quote doesn't mean what you think it means. The velocity factor equation is appropriate for quarterwave resonance *and* any other length at the same frequency. The graph in the next column over shows coils of 10,000 turns per wavelength. It does NOT limit them to any length so your argument is bogus. Their goal was to find a VF equation that worked for quarterwave resonance but it works for a lot more than quarterwave resonance. It holds for any length as can be seen from Fig. 1. So let's throw the topic back to you. Too late, I asked you first. Where are the laws of physics to back up your assertions? Certainly not contained in the Corum papers. Please provide some reference that asserts that the VF of a coil varies with its length while keeping all other parameters constant. The coil being modeled is 48 turns per foot. The wavelength is 246 feet. 48*246 = 11,808 turns per wavelength. That's on the Corum chart. There is NO minimum or maximum length requirement or constraint. According to the paper, the velocity factor is within 10% no matter what the length of the coil. So holding all the variables constant in the velocity factor equation and changing only the length is a valid way to calculate the approximate delay through the coil. It's the best way that we have so far. It is infinitely better than using a signal with unchanging phase to try to measure phase shift. So where and how does the Vf transition occur? Just as in a transmission line, a VF transition occurs at an impedance discontinuity. For a complete helical antenna, there is no impedance discontinuity. For an antenna containing a coil and wire, there is an impedance discontinuity at the coil/wire interface. -- 73, Cecil http://www.qsl.net/w5dxp |
Current across the antenna loading coil - from scratch
Reg Edwards wrote:
What is the failure mode? Is it a sudden catastropic failure? Or does it fail very slowly, gradually and gently? It fails gradually. It fails earlier for phase calculations than it does for magnitude calculations. That's why the phase shifts reported here are completely invalid. Here's how it goes: 1. There is no phase shift through a lumped inductance. 2. The standing wave current with its unchanging phase shows zero phase shift through a loading coil. 3. Therefore, a real world loading shows zero phase shift just like a lumped inductance. The proof was preassumed and invalid measurements support the preassumed proof. Case closed! -- 73, Cecil http://www.qsl.net/w5dxp |
Current across the antenna loading coil - from scratch
Tom Donaly wrote:
There are two Drs. Corum. Perhaps they're a husband-husband team. I believe they are brothers. -- 73, Cecil http://www.qsl.net/w5dxp |
Current across the antenna loading coil - from scratch
Cecil,
The "quote" was from your message, not the Corum paper. It is highly likely that it does not mean what I think it means. It probably does not even mean the same thing to you after a few minutes. As for the Corum paper, would you be so kind as to point out the page where it is written: The velocity factor equation is appropriate for quarterwave resonance *and* any other length at the same frequency. I found the section that says the formula is appropriate at resonance, and I must have missed the part that says the formula works for any length as long as the frequency is maintained. You still have not explained at what point the transition from Vf ~ 1 to Vf 0.02 occurs. 73, Gene W4SZ Cecil Moore wrote: Gene Fuller wrote: You have really lost it. I gave you the exact quote, and you then proceed to talk about something else. Your quote doesn't mean what you think it means. The velocity factor equation is appropriate for quarterwave resonance *and* any other length at the same frequency. The graph in the next column over shows coils of 10,000 turns per wavelength. It does NOT limit them to any length so your argument is bogus. Their goal was to find a VF equation that worked for quarterwave resonance but it works for a lot more than quarterwave resonance. It holds for any length as can be seen from Fig. 1. |
Current across the antenna loading coil - from scratch
Gene Fuller wrote:
As for the Corum paper, would you be so kind as to point out the page where it is written: The velocity factor equation is appropriate for quarterwave resonance *and* any other length at the same frequency. I already told you - same page, Fig. 1 where that VF equation is plotted. There is absolutely no reference to coil length in Fig. 1. The only independent variables are the diameter/wavelength ratio and the turns/wavelength ratio. For any length coil with the above fixed parameters, including frequency, the VF is constant within 10%. I found the section that says the formula is appropriate at resonance, and I must have missed the part that says the formula works for any length as long as the frequency is maintained. "We have found that this expression gives acceptable results (errors less than 10%) for most practical applications that involve wave propagation on helical resonators ..." Absolutely no mention of 14WL self-resonance. You still have not explained at what point the transition from Vf ~ 1 to Vf 0.02 occurs. It is explained perfectly in Fig. 1 where the VF scale goes from 0.0 to 1.0. Come over to my house for a beer and I will teach you how to read that graph. Exactly as would be expected, holding the diameter/wavelength ratio constant, as the helical is wound tighter and tighter, the VF decreases. -- 73, Cecil http://www.qsl.net/w5dxp |
Current across the antenna loading coil - from scratch
Cecil Moore wrote:
"We have found that this expression gives acceptable results (errors less than 10%) for most practical applications that involve wave propagation on helical resonators ..." Absolutely no mention of 14WL self-resonance. Cecil, Oh darn! There's that nasty reference to "resonator" again. You really need to read the paper again and attempt to understand it. Try the left-hand column on the page for the fundamental mathematical limitation that underlies everything else on the page, including Figure 1. Since this is a question of literacy and not technology there is little more to be said here. 73, Gene W4SZ |
Current across the antenna loading coil - from scratch
On Wed, 19 Apr 2006 23:32:53 GMT, Gene Fuller
wrote: Oh darn! There's that nasty reference to "resonator" again. Resonant [6], resonance [11], resonator (the title of the paper)[24] are littered throughout so frequently [41 times in 10 pages] that you would have to get a dispensation from the pope to talk about pure resistance. |
Current across the antenna loading coil - from scratch
Reg Edwards wrote:
"Cecil Moore" wrote in message . com... Gene Fuller wrote: Cecil Moore wrote: A 75m bugcatcher coil is self resonant at 6.6 MHz. That's near 4 MHz. Where is all your irrationality coming from? The exact quote from your message on April 11, at 9:57 am is copied below. I don't see anything about a bugcatcher coil. The coil being discussed is a bugcatcher coil modeled in EZNEC. Since the Corum paper highlighted the limitation for applicability of the magic formula it is possible he thought that the limitation might be important. The limitation that Dr. Corum highlighted was the failure of the lumped circuit model when the coil is self-resonant. He says that when we are within 17% of self-resonance, the lumped circuit model fails. Have you anything besides faith to prove that your model is valid within 60% of self-resonance? Please describe the physics behind a radical change in velocity factor (at the same frequency) when a coil is cut in half. -- ======================================== Dear Cec, What is the failure mode? Is it a sudden catastropic failure? Or does it fail very slowly, gradually and gently? What is Dr.Corum a doctor of? From your quotes he sounds like a Quack. Or is he a Witch? What does he have to say about Fractals, E-H and the other wierd contraptions? How many other worshipping followers does he have besides yourself? Or are you just pulling our varicose-veined legs? All rhetorical questions of course. Answers not required. ---- Your old, well-intentioned pal, Reg. I summoned the spirit of the late Bert Newman G2FIX. Bert thinks Cecil is full of beans. Dave K8MN |
Current across the antenna loading coil - from scratch
Cecil Moore wrote: "We have found that this expression gives acceptable results (errors less than 10%) for most practical applications that involve wave propagation on helical resonators ..." Absolutely no mention of 14WL self-resonance. Gene Fuller wrote: Oh darn! There's that nasty reference to "resonator" again. You really need to read the paper again and attempt to understand it. Try the left-hand column on the page for the fundamental mathematical limitation that underlies everything else on the page, including Figure 1. Since this is a question of literacy and not technology there is little more to be said here. Gene, I can't believe you are still trying to get Cecil to actually read the paper he is misquoting. I've seen his debating style before. It's the last man standing wins, no matter how obviously wrong he is. You'll never win that kind of debate with logic or science Gene. Never. 73 Tom |
Current across the antenna loading coil - from scratch
Gene Fuller wrote:
Oh darn! There's that nasty reference to "resonator" again. You really need to read the paper again and attempt to understand it. Uhhhhh Gene, a 75m bugcatcher coil is a "resonator" that resonates an 8 foot mobile antenna on 75m. Take a look at Figure 2 in Dr. Corum's paper. It looks just like a top- loaded 160m mobile antenna. Try the left-hand column on the page for the fundamental mathematical limitation that underlies everything else on the page, including Figure 1. There is a test equation to see if a particular coil is outside the fundamental mathematicdal limitations. A 75m bugcatcher coil is less than half the limit value. Let me show you how to use Fig. 1. The coil that we have been discussing is 6 inches in diameter and has 4 turns per inch. That makes D/lamda = 2.0 x 10^3. That's just about in the middle of the graphic. The turns per wavelength is 48*246 = 11,808. That's just to the left of the left hand curve. Reading the velocity factor from the graph gives about 0.03 for that coil. It's a piece of cake if you understand the physics involved. -- 73, Cecil http://www.qsl.net/w5dxp |
Current across the antenna loading coil - from scratch
wrote:
I can't believe you are still trying to get Cecil to actually read the paper he is misquoting. Unfortunately for your lumped circuit religion, I am not misquoting anything. Page 4 contains a test to see if a coil falls within the limitations of the velocity factor equation. A 75m bugcatcher coil is less than half the upper limit. Here's the calculation: 5*N*D^2/lamda 1 N is turns per unit length and D is the diameter. 5*48*0.5^2/246 = 0.24 1 Therefore, the graph in Fig. 1 is valid for 75m bugcatcher coils and the velocity factor is around 0.02. The VF equation yields the same value as the graph. The lumped circuit model is known to fail. Dr. Corum knows where it fails. Most people on this newsgroup don't know. And when it does fail, the distributed network model gives valid results. Why would you ever choose a model known to fail without knowing where it fails when you could be using a model known to be valid? -- 73, Cecil http://www.qsl.net/w5dxp |
Current across the antenna loading coil - from scratch
Cecil Moore wrote:
wrote: I can't believe you are still trying to get Cecil to actually read the paper he is misquoting. Unfortunately for your lumped circuit religion, I am not misquoting anything. Page 4 contains a test to see if a coil falls within the limitations of the velocity factor equation. A 75m bugcatcher coil is less than half the upper limit. Here's the calculation: 5*N*D^2/lamda 1 N is turns per unit length and D is the diameter. Cecil, Selective quoting can have the same effect as misquoting. If one goes back a few words in the same long sentence it can be observed that the more complete limitation is stated as: "... an approximation for M has been determined by Kandoian and Sichak which is *appropriate for quarter-wave resonance* and is valid for helices with 5*N*D^2/lambda 1 ..." [emphasis was in the original] You apparently choose to accept the second half of the condition while ignoring the first half. In most cases the "AND" construction means both parts apply. Do you really think the Vf is dependent only on the turn density and not the number of turns? Corum never says such a thing, since the number of turns is dictated by the resonance requirement. How far down does your magic extend? To half the turns needed for resonance? To one turn? To less than one turn? Where is the transition in Vf from the ~1 for zero turns to ~0.02 for a resonant coil? For anyone still reading who is bored (everyone) or confused by this topic (perhaps) the importance to the subject at hand is that Cecil has mis-used this reference paper to "prove" that the 75 meter loading coil replaces approximately 45 degrees of the original unloaded quarter wave antenna. After his long struggle to prove his point with modeling, and achieving only 10 degrees of phase replacement, he abandoned that approach for this latest futile attempt. The "missing" portion of the test antenna is about 75 degrees, so 45 degrees would barely squeak in under the 59% precision rule. 73, Gene W4SZ |
Current across the antenna loading coil - from scratch
"Gene Fuller" wrote: Selective quoting can have the same effect as misquoting. If one goes back a few words in the same long sentence it can be observed that the more complete limitation is stated as: "... an approximation for M has been determined by Kandoian and Sichak which is *appropriate for quarter-wave resonance* and is valid for helices with 5*N*D^2/lambda 1 ..." I have already explained that to you twice now, Gene. This is the third time so listen up. They were looking for a formula "appropriate for quarter-wave resonance" and they found one that works for lengths other than a quarter-wavelength. If it worked *only* for quarter-wave resonance, they would have said so. You are confusing a mutually inclusive statement with a mutually exclusive statement. Do you really think the Vf is dependent only on the turn density and not the number of turns? Corum never says such a thing, ... Already asked and answered. He certainly does imply such a thing in Fig. 1. The VF is dependent only on the turn density and the diameter of the coil. The number of turns affects the length of the coil. The length of the coil is NOT a parameter in the graphic nor does it appear in the equation. Does a 1/4WL transmission line have a different VF when it is increased to 1/2WL? Where is the transition in Vf from the ~1 for zero turns to ~0.02 for a resonant coil? Already asked and answered. If you cannot read Fig 1, then you have a problem. The VF in the graphic goes from 0.0 to 1.0. After his long struggle to prove his point with modeling, and achieving only 10 degrees of phase replacement, he abandoned that approach for this latest futile attempt. The voltage was 67 degrees out of phase with the current so we weren't dealing with traveling waves. That's why I abandoned it - because I was on the verge of making the same mistake that W7EL and W8JI already made - trusting measurements in the presence of standing waves. The "missing" portion of the test antenna is about 75 degrees, so 45 degrees would barely squeak in under the 59% precision rule. Once again, there is no "missing" portion of an antenna. The delay through the loading coil is what it is. There is absolutely no requirement that it be a certain number of degrees. What is required is that (Vfor+Vref)/(Ifor+Iref) be purely resistive at the feedpoint. There is absolutely no requirement for the antenna to be 90 degrees long. That is just another one of your many strawmen. I am trying to zero in on the technical facts. What are you trying to do? -- 73, Cecil, W5DXP |
Current across the antenna loading coil - from scratch
"Gene Fuller" wrote in message: Where is the transition in Vf from the ~1 for zero turns to ~0.02 for a resonant coil? Take the VF=0.02 resonant coil and divide it into two equal coils. Do you really expect the two coils to have VFs of 1.0 while their end-to-end combination results in a VF of 0.02? Please quote the laws of physics that allows such to happen. -- 73, Cecil, W5DXP |
Current across the antenna loading coil - from scratch
Cecil Moore wrote:
"Gene Fuller" wrote: Do you really think the Vf is dependent only on the turn density and not the number of turns? Corum never says such a thing, ... Already asked and answered. He certainly does imply such a thing in Fig. 1. The VF is dependent only on the turn density and the diameter of the coil. The number of turns affects the length of the coil. The length of the coil is NOT a parameter in the graphic nor does it appear in the equation. Does a 1/4WL transmission line have a different VF when it is increased to 1/2WL? Where is the transition in Vf from the ~1 for zero turns to ~0.02 for a resonant coil? Already asked and answered. If you cannot read Fig 1, then you have a problem. The VF in the graphic goes from 0.0 to 1.0. Cecil, You just contradicted yourself. Yes, indeed, Fig.1 shows Vf going from 0.0 to 1.0. But as you pointed out, there is no dependency on the number of turns anywhere in the chart axes or in the plotted data. It would be useful if you looked at the caption on that figure to attempt to understand what is actually being plotted. The vertical scale is Vf and the horizontal scale is D/lambda. The parameter attached to each curve is "N", which is defined as the turns per wavelength. We would expect a very short coil to look like a straight wire, with a Vf near 1.0. How does the Vf transition to 0.02 for a resonant coil occur? That transition is most certainly NOT shown in Fig. 1. 73, Gene W4SZ |
Current across the antenna loading coil - from scratch
On Thu, 20 Apr 2006 15:01:57 GMT, Gene Fuller
wrote: For anyone still reading who is bored Hi Gene, To ask about those still reading, there is one very good reason why the thread persists: topic drift as your post has just raised the opportunity to: 1. argue the original quotation by shifting authors; 2. argue the subquotation in terms of ANDing where his sum of the parts never equal the whole; 3. respond to "do you think the Vf" in terms that diverge from your yes/no; 4. argue no one uses a one turn coil load for 160M (this is all getting too easy to dissemble); 5. discuss transitions when you obviously don't believe they exist (more arguments over inconsequentials); 6. counter-claim old claims (aka correcting what he would call your bad context); 7. argue models (he has already questioned EZNEC's capacity in some form - you will only tread that old ground once again); 8. fight over "missing" portions of the antenna - Cecil can prove he never "exactly" said it did!; 9. ... and more through finer parsing than found here (and it is guaranteed to be found, that has been amply demonstrated when you feed the troll). Those exchanges are like watching someone chase the clown in a revolving door with discarded lines of attack flying out like grass clippings from a lawn mower. Cecil has never been able to hold his ground to one point when I've drilled down instead of following the outrageous. No one want to abandon the only true content, the comedy; but, really, the knots of argument are far more deterministic than the technical issue supposedly being discussed. 73's Richard Clark, KB7QHC |
Current across the antenna loading coil - from scratch
Cecil Moore wrote:
"Gene Fuller" wrote in message: Where is the transition in Vf from the ~1 for zero turns to ~0.02 for a resonant coil? Take the VF=0.02 resonant coil and divide it into two equal coils. Do you really expect the two coils to have VFs of 1.0 while their end-to-end combination results in a VF of 0.02? Please quote the laws of physics that allows such to happen. -- 73, Cecil, W5DXP Cecil, What is the mystery? Have you never seen a response curve for a resonant condition? It is not exactly linear. You are the expert on Vf. You assert without proof that a half-length coil has the same Vf as the full-length resonant coil. OK, even if I accepted that supposition, what happens at a quarter-length or at a tenth-length? I am simply asking how the function changes between the "known" limits of 1.0 and 0.02. You have repeatedly ducked any sort of answer. 73, Gene W4SZ |
Current across the antenna loading coil - from scratch
"Gene Fuller" wrote: We would expect a very short coil to look like a straight wire, ... There you go again. We are not talking about very short coils. We are talking about big honking 75m bugcatcher coils. We are talking about taking a 1/4WL self-resonant coil and cutting it into two equal sized coils. The VF is not likely to change by more than 10%. How does the Vf transition to 0.02 for a resonant coil occur? That transition is most certainly NOT shown in Fig. 1. Of course it is shown. Draw a vertical line at 10^-3. The 10k turns per lamda coil has a VF of 0.07. The 50 turns per lamda has a VF of 0.86. Exactly the same principle applies to your question. -- 73, Cecil, W5DXP |
Current across the antenna loading coil - from scratch
Richard Clark wrote:
On Thu, 20 Apr 2006 15:01:57 GMT, Gene Fuller wrote: For anyone still reading who is bored Hi Gene, To ask about those still reading, there is one very good reason why the thread persists: topic drift as your post has just raised the opportunity to: 1. argue the original quotation by shifting authors; 2. argue the subquotation in terms of ANDing where his sum of the parts never equal the whole; 3. respond to "do you think the Vf" in terms that diverge from your yes/no; 4. argue no one uses a one turn coil load for 160M (this is all getting too easy to dissemble); 5. discuss transitions when you obviously don't believe they exist (more arguments over inconsequentials); 6. counter-claim old claims (aka correcting what he would call your bad context); 7. argue models (he has already questioned EZNEC's capacity in some form - you will only tread that old ground once again); 8. fight over "missing" portions of the antenna - Cecil can prove he never "exactly" said it did!; 9. ... and more through finer parsing than found here (and it is guaranteed to be found, that has been amply demonstrated when you feed the troll). Those exchanges are like watching someone chase the clown in a revolving door with discarded lines of attack flying out like grass clippings from a lawn mower. Cecil has never been able to hold his ground to one point when I've drilled down instead of following the outrageous. No one want to abandon the only true content, the comedy; but, really, the knots of argument are far more deterministic than the technical issue supposedly being discussed. 73's Richard Clark, KB7QHC Richard, I gave up on this thread a couple of weeks ago, largely because it had drifted. However, it came right back to the original topic when the velocity-factor-based 45 degree replacement item came up. Cecil and his friends now deny they ever said anything about coils replacing the "degrees" of missing wire, but they keep coming back to the same position again and again. 73, Gene W4SZ |
Current across the antenna loading coil - from scratch
"Gene Fuller" wrote: I am simply asking how the function changes between the "known" limits of 1.0 and 0.02. You have repeatedly ducked any sort of answer. On the contrary, I just posted the answer for the third time. The Y-axis answers your question. Hold the diameter/lamda ratio constant and vary the turns/lamda to answer your question. Do I have to plot zero turns/lamda for you? -- 73, Cecil, W5DXP |
Current across the antenna loading coil - from scratch
On Thu, 20 Apr 2006 17:46:01 GMT, Gene Fuller
wrote: I gave up on this thread a couple of weeks ago, largely because it had drifted. However, it came right back to the original topic when the velocity-factor-based 45 degree replacement item came up. Cecil and his friends now deny they ever said anything about coils replacing the "degrees" of missing wire, but they keep coming back to the same position again and again. Hi Gene, Well, you will never find a definitive quote to pin to Cecil that the 45 degrees is replaced by a coil. That ain't gonna happen. Cecil doesn't need to say it when so many are ready to interpret this from his crafted comments which lead to no other conclusion. As for Vf, you can argue that 'till you are blue in the face, but given a 59% slop factor that Cecil embraces, any of his computations can transform gold into lead. So, the comedy is the only thing left, and it comes like a wildcat gusher if you simply drill down - on one point - and he is left claiming the most absurd things that are self-negating (you don't even have to argue the point it gets so funny). It doesn't take very long either. 73's Richard Clark, KB7QHC |
Current across the antenna loading coil - from scratch
On Thu, 20 Apr 2006 17:45:39 GMT, "Cecil Moore"
wrote: How does the Vf transition to 0.02 for a resonant coil occur? That transition is most certainly NOT shown in Fig. 1. Of course it is shown. Draw a vertical line at 10^-3. The 10k turns per lamda coil That is for coil A has a VF of 0.07. The 50 turns per lamda That is for coil B has a VF of 0.86. Well, in fact it does not (and nothing shown on the graph along that ordinal line does). Do we now hear the pity card played about poor eyesight? Or the pity card played about poor computational skills (±59%)? Or the pity card played for the confusion of old age when two coils are substituted in the old shell game? |
Current across the antenna loading coil - from scratch
"Richard Clark" wrote:
w5dxp wrote: Of course it is shown. Draw a vertical line at 10^-3. The 10k turns per lamda coil That is for coil A has a VF of 0.07. The 50 turns per lamda That is for coil B has a VF of 0.86. Well, in fact it does not (and nothing shown on the graph along that ordinal line does). What happened should be obvious. I correctly used the 10^-3 vertical line for the first one and accidentally used the 0.01 vertical line for the second one. The first observation is OK. The second should be changed to 500 turns per lamda with a VF of 0.96. The same principle still applies. As the turns/lamda increases, the VF decreases while keeping the diameter and frequency the same. -- 73, Cecil, W5DXP |
Current across the antenna loading coil - from scratch
On Thu, 20 Apr 2006 18:46:09 GMT, "Cecil Moore"
wrote: What happened should be obvious. You played the pity card. It was so obvious that I forecast that immediately. The second should be changed to 500 turns per lamda with a VF of 0.96. Only 1000% off on the turns count - not bad for the first step in a reading comprehension test. Further interpretations suffer equally. |
Current across the antenna loading coil - from scratch
On Thu, 20 Apr 2006 17:45:39 GMT, "Cecil Moore"
wrote: How does the Vf transition to 0.02 for a resonant coil occur? That transition is most certainly NOT shown in Fig. 1. Of course it is shown. Draw a vertical line at 10^-3. The 10k turns per lamda coil That is for coil A has a VF of 0.07. The 50 turns per lamda That is for coil B has a VF of 0.86. Let's review this response for its pity quotient: Asked: At one length, one coil exhibits Vf = 0.02, reduce the coil length, what length for the SAME coil would that be to render Vf = 0.2 for instance? 1. We are not changing frequency; 2. we are not changing diameter/lambda (nor in fact changing diameter OR lambda); 3. we are not changing pitch/lambda (nor in fact changing pitch OR lambda). Answer? Change the coil, change the Vf, and the turns/lamda. ************* W R O N G ! ***************** Draw another pity card and do not pass go. |
Current across the antenna loading coil - from scratch
"Richard Clark" wrote: Asked: At one length, one coil exhibits Vf = 0.02, reduce the coil length, what length for the SAME coil would that be to render Vf = 0.2 for instance? 3. we are not changing pitch/lambda So what is the pitch for one turn? -- 73, Cecil, W5DXP |
Current across the antenna loading coil - from scratch
On Thu, 20 Apr 2006 12:45:15 -0700, Richard Clark
wrote: Asked: At one length, one coil exhibits Vf = 0.02, reduce the coil length, what length for the SAME coil would that be to render Vf = 0.2 for instance? Well, let's help Cecil navigate this with his MENSA walker. First, myopic translations of SAME coil are bound to confuse him into thinking that this means the coil was never shortened. We'll put a bullet into that suffering idea right now - the coil is shorter. Investigating Fig. 1 reveals there is no way to resolve the Vf through shortening a coil. Only Cecil could argue there's a pony in all that horse****, so while he's saddling himself to that mound, let's proceed to see why his dotaged enthusiasm is ill-founded. Fig. 1 is based upon the formula (32). Nowhere in that formula is there a turns. Turns may be found, but the specification, s, is for pitch. Pitch for any coil remains the same irrespective of its length. Frequency does not change, diameter does not change; it then follows that Vf does not change when a coil is shortened. So, the short answer that eludes Cecil is that the question above (or its variants) has no other answer than the one value already provided. By reductio ad absurdum, any kink in a wire that describes an arc of a helix with a large D for a small s; and Cecil would impose his curious theory's delay based on his poor reading skills on Corum². 73's Richard Clark, KB7QHC |
Current across the antenna loading coil - from scratch
On Thu, 20 Apr 2006 19:56:57 GMT, "Cecil Moore"
wrote: So what is the pitch for one turn? The same when there were n turns. It doesn't change with length. When can we take the training wheels off your computer? |
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