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On Fri, 30 Jan 2004 14:06:27 -0600, Cecil Moore
wrote: |Wes Stewart wrote: | If you would actually read the paper *before* beginning | to argue, you would see that all of the modeling can be done in EZNEC | and I also supplied the .ez files so you don't have to create the coil | models yourself. | |I just looked at the paper again and I don't see any files to download. |Where are the files? I only have DOS-based EZNEC. Will it still work? Not sure. I tried installing EZNEC 2.0 on this machine and it would not take. I tried EZNEC 1.0 and it installed but doesn't want to run on Win-XP and I not going to waste time trying. It did open the files however. My XYL has the dual boot machine with Win98 tied up and I'm not going to ask her to give it up. Not when she's just authorized the purchase of a new $2K table saw. :-D | | Now, I showed you mine why don't you show us yours. Stop asking | whether we would like to see your model files and just put them on | your web page where we can take them or leave them. | |Don't know how. But assuming I can learn how to do that in HTML, I'll |try to post those files tomorrow. As you can see from my home page I'm not, nor do I want to be, a web page designer. But even I know that you can just ftp your files to your web page. You don't need to create a link on a page, just tell us the file name. I do it all the time. |
Dave wrote,
Tdonaly wrote: SNIP O.k., Cecil, let's suppose you're right. Since there's more current going into a coil than coming out, then the coil must be storing charge, somewhere. Charge is conserved, Cecil. You can't create it or destroy it. If the coil is storing charge somewhere it must be acting like a capacitor, which is famous for doing just that. Where does the coil store its charge? 73, Tom Donaly, KA6RUH Two possibilities exist: 1) Charge is stored in the interwinding capacitance; or, 2) EM radiation is occurring in the coil i.e. the winding length is a significant portion of a wavelength!! What's your Physics say? It says you can radiate energy, but radiating charge is another proposition. Also, charge has to be stored on the surface of the conductor, not in it's own field. Energy can be stored there, though. 73, Tom Donaly, KA6RUH |
Tdonaly wrote:
This is vintage Moore. I know you're never going to admit that you don't understand this stuff. That's fine. I'm going to leave the field to you and your pal, Jim, until the next time you start trying to pawn off your simple ideas as The Truth. Vintage Donaly. When you lose the argument, mount an ad hominem attack. Why don't you respond to the questions? True or False? It is possible to measure zero net amps in a transmission line while measuring 100 net amps 1/4WL away. ___________ That violates the principle of conservation of charge. _________ Hint: The net current can have a different magnitude at two ends of a transmission line without violating the conservation of charge principle. The net current can have a different magnitude at two ends of a coil without violating the conservation of charge principle. The difference in current is possible because of the standing waves. -- 73, Cecil http://www.qsl.net/w5dxp -----= Posted via Newsfeeds.Com, Uncensored Usenet News =----- http://www.newsfeeds.com - The #1 Newsgroup Service in the World! -----== Over 100,000 Newsgroups - 19 Different Servers! =----- |
Wes Stewart wrote:
As you can see from my home page I'm not, nor do I want to be, a web page designer. But even I know that you can just ftp your files to your web page. You don't need to create a link on a page, just tell us the file name. I do it all the time. Wow, that's news to me. I knew that one could access .htm and .gif files with a browser, but .ez files? That's pretty neat. Wes, I took a brief look at your coil .ez files. There seems to be a current taper through the coil. -- 73, Cecil http://www.qsl.net/w5dxp -----= Posted via Newsfeeds.Com, Uncensored Usenet News =----- http://www.newsfeeds.com - The #1 Newsgroup Service in the World! -----== Over 100,000 Newsgroups - 19 Different Servers! =----- |
Tdonaly wrote:
It says you can radiate energy, but radiating charge is another proposition. Also, charge has to be stored on the surface of the conductor, not in it's own field. Energy can be stored there, though. An unterminated transmission line reads zero net current at one point. Does that mean there is no charge on the entire line? Do you understand how net charge can clump together for standing waves between the two zero current points? -- 73, Cecil http://www.qsl.net/w5dxp -----= Posted via Newsfeeds.Com, Uncensored Usenet News =----- http://www.newsfeeds.com - The #1 Newsgroup Service in the World! -----== Over 100,000 Newsgroups - 19 Different Servers! =----- |
Tdonaly wrote:
"In order to show that an inductor can be treated as a transmission line, in the way that you want to do it, you have to show that your inductor has an exponential potential gradient along its length when terminated in a certain impedance." Inductors are used to replace a missing length of an antenna which often would be located at the inductor. The coil is an antenna length surrogate. Its delay and impedance characteristics match that of the missing length of straight wire. The logic is simple. Natural growth or decline is a change based upon a certain fraction of the available energy. One segment of of a radiator or a line extracts a certain energy fraction. The next similar segment extracts the same percentage, but the extraction is larger or smaller because the remaining energy it has to work with is is larger or smaller. It`s a natural law of growth or decline. It is "exponential" because that`s the name given to change "as a percentage of the energy of the energy involved". It`s growth or shrinkage at the "natural rate". It is exactly due to agreement in the amplitude and phase behaviors of antennas and transmission lines that Terman refers his readers to his transmission line section to explain antennas. Best regards, Richard Harrson, KB5WZ |
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On Fri, 30 Jan 2004 19:22:03 -0700, Wes Stewart
wrote: But even I know that you can just ftp your files to your web page. You don't need to create a link on a page, just tell us the file name. I do it all the time. This is the up and coming thing of pre-schoolers now. 45% are making their own web sites. They also know EM theory better. 73's Richard Clark, KB7QHC |
Richard Harrison wrote:
Inductors are used to replace a missing length of an antenna which often would be located at the inductor. The coil is an antenna length surrogate. Its delay and impedance characteristics match that of the missing length of straight wire. Hi Richard, I know what you mean and it is not an *exact* match. (And you did not say or imply that it was an exact match.) From a 1/4WL monopole to a loaded mobile antenna, the feedpoint impedance can drop from about 35 ohms to about 12 ohms. That probably means that the in-phase reflected current has increased from one configuration to the other and the out-of-phase reflected voltage has also increased. In other words, the antenna reflection coefficient is higher for the loaded monopole which would make it less efficient. We know that, at resonance, the net feedpoint voltage is in phase with the net feedpoint current. But the component forward and reflected currents do not have to be in phase. And the component forward and reflected voltages do not have to be 180 degrees out of phase. In fact, there is a considerable amount of interference going on at the feedpoint of a standing-wave antenna. If one calculates or measures the s11 reflection coefficient s-parameter at the feedpoint of a dipole, it will have a magnitude in the ballpark of about 0.85 -- 73, Cecil http://www.qsl.net/w5dxp -----= Posted via Newsfeeds.Com, Uncensored Usenet News =----- http://www.newsfeeds.com - The #1 Newsgroup Service in the World! -----== Over 100,000 Newsgroups - 19 Different Servers! =----- |
Cecil Moore wrote:
Dave Shrader wrote: Two possibilities exist: 1) Charge is stored in the interwinding capacitance; or, 2) EM radiation is occurring in the coil i.e. the winding length is a significant portion of a wavelength!! What's your Physics say? Don't know about Tom's physics, but mine says the net current in an unterminated transmission line can be zero at one point and 100 amps 1/4 WL away. Tom (apparently) thinks that is a violation of the conservation of charge principle. Hey Cecil, What's this 'conservation of charge'? I'm aware of the 'Conservation of Energy', 'Conservation of Momentum', 'conservation of our wetlands', etc. For your example: Conservation of Energy yields: 1/2*L*I^2 = 1/2*C*V^2 at the high current end and the high voltage end respectively. My Physics and my brain must be getting old!! |
Dave Shrader wrote:
Hey Cecil, What's this 'conservation of charge'? From _University_Physics_ 9th edition by Young and Freedman: "principle of conservation of charge: The algebraic sum of all the electric charges in any closed system is constant." Example: If one combines a proton (+1) and an electron (-1) one gets a neutron (0) which will often decay back into a proton (+1) and an electron (-1). In practice, it means that if N electrons flow into both ends of a coil during 1/2 cycle, N electrons will flow out of both ends of the same coil during the next 1/2 cycle. Thus, current flowing into both ends of a phase-reversing coil at the same time does NOT violate the conservation of charge principle when averaged over an entire cycle. -- 73, Cecil http://www.qsl.net/w5dxp -----= Posted via Newsfeeds.Com, Uncensored Usenet News =----- http://www.newsfeeds.com - The #1 Newsgroup Service in the World! -----== Over 100,000 Newsgroups - 19 Different Servers! =----- |
Wes Stewart wrote:
wrote: |Don't know how. But assuming I can learn how to do that in HTML, I'll |try to post those files tomorrow. As you can see from my home page I'm not, nor do I want to be, a web page designer. But even I know that you can just ftp your files to your web page. You don't need to create a link on a page, just tell us the file name. I do it all the time. Thanks for the tips, Wes, and it does work. The names of the .EZ files are on the .gif graphic that I prepared which illustrates the current magnitudes and phases for 3/2WL phased arrays. http://www.qsl.net/w5dxp/phasesbw.gif -- 73, Cecil, W5DXP -----= Posted via Newsfeeds.Com, Uncensored Usenet News =----- http://www.newsfeeds.com - The #1 Newsgroup Service in the World! -----== Over 100,000 Newsgroups - 19 Different Servers! =----- |
Cecil,
This has become unusually entertaining. You have declared experimentation to be unnecessary, e.g., your Diamond antenna story. You have declared math models to be unnecessary and incorrect on numerous occasions. I have worked with a lot of scientists in my career; some were experimentally biased, some were theoretically biased, and many understood that both approaches were useful. However, I do not believe I have ever encountered a "scientist" who rejected both experimental and mathematical approaches at the same time. 73, Gene W4SZ Cecil Moore wrote: snip If your math disagrees with reality, it is simply wrong and has turned into a religious belief. You are free to worship at the alter of mathematics but please don't expect the rest of us scientists to join you there. |
Cecil
Regarding inductance and computor programs and the drawings shown in your post addition May I suggest the following Since a straight line radiator contains the elements of resistance, capacitance and inductance it can also be shown as a loop radiator ( many books show it that way ) If you replace some or all of the center portion by a loop circuit it will clearly show a phase change. This method serves as a substitute for the insertion of a lumped load and changing it from a dimensionaless object to one of dimensions.that can radiate. If one shows this change it would add insight to the the drawings where inductor physical length can be portrayed. Regards Art "Cecil Moore" wrote in message ... Wes Stewart wrote: wrote: |Don't know how. But assuming I can learn how to do that in HTML, I'll |try to post those files tomorrow. As you can see from my home page I'm not, nor do I want to be, a web page designer. But even I know that you can just ftp your files to your web page. You don't need to create a link on a page, just tell us the file name. I do it all the time. Thanks for the tips, Wes, and it does work. The names of the .EZ files are on the .gif graphic that I prepared which illustrates the current magnitudes and phases for 3/2WL phased arrays. http://www.qsl.net/w5dxp/phasesbw.gif -- 73, Cecil, W5DXP -----= Posted via Newsfeeds.Com, Uncensored Usenet News =----- http://www.newsfeeds.com - The #1 Newsgroup Service in the World! -----== Over 100,000 Newsgroups - 19 Different Servers! =----- |
Gene Fuller wrote:
However, I do not believe I have ever encountered a "scientist" who rejected both experimental and mathematical approaches at the same time. Gene, experimenting with photocells to prove that day follows night would be a waste of my time. I don't reject the concept of experimenting, just experiments that waste my time for no benefit. If a math model says that day doesn't follow night, it should be rejected. A 3/4WL monopole is not a good UHF antenna. However, if the bottom 1/4WL is separated from the top 1/2WL by a phase-reversing coil, the antenna has gain over a quarterwave monopole. The Diamond antenna engineers don't care about your sacred cows. -- 73, Cecil http://www.qsl.net/w5dxp -----= Posted via Newsfeeds.Com, Uncensored Usenet News =----- http://www.newsfeeds.com - The #1 Newsgroup Service in the World! -----== Over 100,000 Newsgroups - 19 Different Servers! =----- |
Cecil Moore wrote:
Thanks for the tips, Wes, and it does work. The names of the .EZ files are on the .gif graphic that I prepared which illustrates the current magnitudes and phases for 3/2WL phased arrays. http://www.qsl.net/w5dxp/phasesbw.gif For anyone who wants to download those EZNEC files, be sure the file names are capitalized - UNIX strikes again. -- 73, Cecil http://www.qsl.net/w5dxp -----= Posted via Newsfeeds.Com, Uncensored Usenet News =----- http://www.newsfeeds.com - The #1 Newsgroup Service in the World! -----== Over 100,000 Newsgroups - 19 Different Servers! =----- |
This has become unusually entertaining.
....... snipydyduda However, I do not believe I have ever encountered a "scientist" who rejected both experimental and mathematical approaches at the same time. 73, Gene W4SZ Hey, this is getting off on the tangent, away from the original "problem". I and Barry W9UCW found, measured differences in the typical loading coil currents in order of 40 - 60%. See article and pictures on my web www.K3BU.us. W8JI and flat earth society proclaimed it can't be so. They argued and "calculated" that current at both ends of a loading coil in quarter wave loaded radiator has to be the same. W5DXP explained why the current is different, other sources and past publications affirm that. As I mentioned, time permitting, I will put together article explaining what is happening, describe experiments that can be replicated by non-believers and elaborate on the significance of the effect on the design of shortened (loaded) antennas. Nobody has argued the seven points I raised earlier, and those who measured, including W8JI found that current IS different (but still says it is NOT). The reality is that current is different, Eznec can't model it, you can speculate and theorize all you want, it will not revert the Earth to be flat. Big men will admit they were wrong, thank the enlighteners and RF life goes on. Yuri, K3BU.us |
Yuri Blanarovich wrote:
Nobody has argued the seven points I raised earlier, and those who measured, including W8JI found that current IS different (but still says it is NOT). The reality is that current is different, Eznec can't model it, ... Yuri, have you read Wes's article? Using wire segments, he modeled a loading coil in EZNEC. His segmented wire model of a coil shows a current taper through the coil. It's on his web page at: http://www.qsl.net/n7ws You can also download Wes's zipped EZNEC files. -- 73, Cecil http://www.qsl.net/w5dxp -----= Posted via Newsfeeds.Com, Uncensored Usenet News =----- http://www.newsfeeds.com - The #1 Newsgroup Service in the World! -----== Over 100,000 Newsgroups - 19 Different Servers! =----- |
Richard Clark wrote,
On 31 Jan 2004 02:18:33 GMT, (Tdonaly) wrote: This is vintage Moore. You were expecting chopped liver? Tom, you and Wes and.... know better. 73's Richard Clark, KB7QHC Hi Richard, yes, we do, but you can't get the monkeys to perform unless you rattle their cage. 73, Tom Donaly |
Yuri,
You are absolutely correct; this thread has drifted beyond recognition. Please note that I have never questioned your experiment or your data. I am merely commenting on the highly unscientific handwaving approach taken RRAA's most prolific "scientist". 73, Gene W4SZ Yuri Blanarovich wrote: This has become unusually entertaining. ....... snipydyduda However, I do not believe I have ever encountered a "scientist" who rejected both experimental and mathematical approaches at the same time. 73, Gene W4SZ Hey, this is getting off on the tangent, away from the original "problem". I and Barry W9UCW found, measured differences in the typical loading coil currents in order of 40 - 60%. See article and pictures on my web www.K3BU.us. W8JI and flat earth society proclaimed it can't be so. They argued and "calculated" that current at both ends of a loading coil in quarter wave loaded radiator has to be the same. W5DXP explained why the current is different, other sources and past publications affirm that. As I mentioned, time permitting, I will put together article explaining what is happening, describe experiments that can be replicated by non-believers and elaborate on the significance of the effect on the design of shortened (loaded) antennas. Nobody has argued the seven points I raised earlier, and those who measured, including W8JI found that current IS different (but still says it is NOT). The reality is that current is different, Eznec can't model it, you can speculate and theorize all you want, it will not revert the Earth to be flat. Big men will admit they were wrong, thank the enlighteners and RF life goes on. Yuri, K3BU.us |
Cecil wrote,
Tdonaly wrote: O.k., Cecil, let's suppose you're right. Since there's more current going into a coil than coming out, then the coil must be storing charge, somewhere. Tom, Tom, Tom, we are talking about *net* current. The net current in an unterminated transmission line can be zero while 1/4WL away, it is 100 amps. Are you asserting that transmission lines don't conserve charge? Would you please put your brain in gear? -- 73, Cecil http://www.qsl.net/w5dxp That's a pretty incoherent post, Cecil. It's tough to have a good argument with you if you won't take the time to understand what I write. Maybe you're trying to sucker me into another 500 post marathon. Forget it, my doctor says I have to eschew effort. I'll attack your ideas again sometime when something else interesting comes up. Otherwise, I'll just be chewing muh cabbage twice. 73, Tom Donaly, KA6RUH |
Tdonaly wrote:
yes, we do, but you can't get the monkeys to perform unless you rattle their cage. Last time I checked, it was the monkeys who believe that a two wavelength helical antenna doesn't have any phase changes. -- 73, Cecil http://www.qsl.net/w5dxp -----= Posted via Newsfeeds.Com, Uncensored Usenet News =----- http://www.newsfeeds.com - The #1 Newsgroup Service in the World! -----== Over 100,000 Newsgroups - 19 Different Servers! =----- |
Gene Fuller wrote:
I am merely commenting on the highly unscientific handwaving approach taken RRAA's most prolific "scientist". Quoting an accepted expert author is handwaving????????????? Do you also believe that there are no phase changes in a two wavelength long helical antenna? -- 73, Cecil http://www.qsl.net/w5dxp -----= Posted via Newsfeeds.Com, Uncensored Usenet News =----- http://www.newsfeeds.com - The #1 Newsgroup Service in the World! -----== Over 100,000 Newsgroups - 19 Different Servers! =----- |
On 31 Jan 2004 19:32:18 GMT, (Tdonaly) wrote:
I have to eschew Gesundheit |
Gene wrote,
Cecil, This has become unusually entertaining. You have declared experimentation to be unnecessary, e.g., your Diamond antenna story. You have declared math models to be unnecessary and incorrect on numerous occasions. I have worked with a lot of scientists in my career; some were experimentally biased, some were theoretically biased, and many understood that both approaches were useful. However, I do not believe I have ever encountered a "scientist" who rejected both experimental and mathematical approaches at the same time. 73, Gene W4SZ Gene, people who come up with simple "my easy-to-understand, the-scientists-think- they-know-everything-but-don't" theories usually don't have much use for either mathematics or experimentation. Indeed, why should they? Since the theories they've thought up in their heads already explain everything, mathematics and experimentation are merely redundant. It's the same logic that was used to burn what was left of the library at Alexandria (after the Christians had destroyed most of it, already): everything you need to know is in the Koran, so these books are useless. 73, Tom Donaly, KA6RUH |
Tdonaly wrote:
Cecil wrote, Tdonaly wrote: O.k., Cecil, let's suppose you're right. Since there's more current going into a coil than coming out, then the coil must be storing charge, somewhere. It's tough to have a good argument with you if you won't take the time to understand what I write. At the point in the cycle where the voltage on the capacitor is zero, all of the charge is *stored in the coil*. At the point in the cycle where the current through the coil is zero, all the charge is stored in the capacitor. I assumed you already knew that. -- 73, Cecil http://www.qsl.net/w5dxp -----= Posted via Newsfeeds.Com, Uncensored Usenet News =----- http://www.newsfeeds.com - The #1 Newsgroup Service in the World! -----== Over 100,000 Newsgroups - 19 Different Servers! =----- |
Tdonaly wrote:
Gene, people who come up with simple "my easy-to-understand, the-scientists-think-they-know-everything-but-don't" theories ... More hand-waving ad hominem attacks instead of one iota of scientific evidence that Kraus is wrong? Tom, how many electrical degrees does an electrical 1/2WL helical antenna occupy? Could it be that there is a 180 degree phase shift in the current from end to end? -- 73, Cecil http://www.qsl.net/w5dxp -----= Posted via Newsfeeds.Com, Uncensored Usenet News =----- http://www.newsfeeds.com - The #1 Newsgroup Service in the World! -----== Over 100,000 Newsgroups - 19 Different Servers! =----- |
The reality is that current is different, Eznec can't model it, ...
Yuri, have you read Wes's article? Using wire segments, he modeled a loading coil in EZNEC. His segmented wire model of a coil shows a current taper through the coil. It's on his web page at: http://www.qsl.net/n7ws You can also download Wes's zipped EZNEC files. -- 73, Cecil http://www.qsl.net/w5dxp Sorry! OK, I will be more precise: Eznec can't model current through zero physical size, but certain value inductance inserted in the antenna element. (As W8JI shows on his web page modeling his mobile antenna, "proving" that current is the same :-) If the inductance is modeled as coiled wire with numerous segments and proper physical dimensions, then the current is modeled and reflects the reality. (Tough to do modeling typical loading coils.) How's that? Sorry I got pulled into the simplificity :-) LB Cebik on his web site also has an example of coil modeled using segments and it shows current drop. I hope it warms up, so I can get out, dig the car from the snow and do some experimenting. First experiment will be with 80m Hustler coil in order to use "standard" (lousy) typical coil. I will paste LCD strip thermometers on the coil to measure temperature changes at various positions, ends, middle. Experiment #1: I will drive DC current through the coil in order to generate heat and observe the temperatures across the coil. I predict that thermometers will be tracking each other very closely or be identical (ideal case). Experiment #2: I will insert the same coil in the Hustler mobile antenna, tune to resonance and fire 100W to it. I will observe temperatures between the end and center and between two ends. I expect difference indicating difference in current at various points. This will be the least disturbing measurement setup, no conductive nothing disturbing the coil or antenna. I am assuming LCD thermometer is RF transparent and I will verify that it does not detune the antenna/coil. Perhaps not very accurate, but sufficient to demonstrate the debated differences. The next measurements will be with current probes and RF ammeters. This will give more accurate values. Any problems with that? Yuri, K3BU.us |
Cecil
Did you find something wrong with my suggestion above? I might also add that when considering coupling to a inductance the multiple placement of inductors does not help a bit since the coupling distance has no real reference points even tho one may decide the radiating member is the same diameter of the coil. This is why I suggested the new aproach. I would be very interested in any errors that you may spot in any part of the above where a dimensionless inductance is changed to one with actual dimensions. Regards Art "Cecil Moore" wrote in message ... Cecil Moore wrote: I just looked at the paper again and I don't see any files to download. Where are the files? I only have DOS-based EZNEC. Will it still work? Sorry Wes, the combination of a small screen, color-blindness, and cataracts causes me to miss a lot of things. I have successfully downloaded your zip files now. -- 73, Cecil http://www.qsl.net/w5dxp -----= Posted via Newsfeeds.Com, Uncensored Usenet News =----- http://www.newsfeeds.com - The #1 Newsgroup Service in the World! -----== Over 100,000 Newsgroups - 19 Different Servers! =----- |
Yuri Blanarovich wrote:
Experiment #1: I will drive DC current through the coil in order to generate heat and observe the temperatures across the coil. Any problems with that? Of course there's a problem with that, Yuri. You absolutely must use a "physically small" coil so the gurus will be right. :-) -- 73, Cecil http://www.qsl.net/w5dxp -----= Posted via Newsfeeds.Com, Uncensored Usenet News =----- http://www.newsfeeds.com - The #1 Newsgroup Service in the World! -----== Over 100,000 Newsgroups - 19 Different Servers! =----- |
While I normally can see your point, even if I disagree with your
conclusions. In this case Cecil, your just plain wrong! "Cecil Moore" wrote in message Thanks for the tips, Wes, and it does work. The names of the .EZ files are on the .gif graphic that I prepared which illustrates the current magnitudes and phases for 3/2WL phased arrays. http://www.qsl.net/w5dxp/phasesbw.gif -- 73, Cecil, W5DXP -----= Posted via Newsfeeds.Com, Uncensored Usenet News =----- http://www.newsfeeds.com - The #1 Newsgroup Service in the World! -----== Over 100,000 Newsgroups - 19 Different Servers! =----- |
Art Unwin KB9MZ wrote:
Did you find something wrong with my suggestion above? Nope, nothing "wrong". I just avoid making assertions when I'm not 95% certain that I am correct. Thus, most of the time, I am unresponsive. I am 95% certain that the average humongous mobile loading coil is not "physically small" and is more like a certain percentage of a helical antenna which indeed does obviously demonstrate a net current gradient. -- 73, Cecil http://www.qsl.net/w5dxp -----= Posted via Newsfeeds.Com, Uncensored Usenet News =----- http://www.newsfeeds.com - The #1 Newsgroup Service in the World! -----== Over 100,000 Newsgroups - 19 Different Servers! =----- |
Wes Stewart wrote:
wrote: |A quick scan of your article produces nothing new. Fine. Then this thread is closed. I apologize, Wes. After closer inspection, I have to disagree with myself. Imax is the reference zero degree point for the "cosine rule". If that point occurs inside the loading coil, then the number of degrees occupied by the loading coil becomes ArcCos(Iin/Imax) + ArcCos(Iout/Imax) This helps to resolve the problem I was having with ArcCos(Iout/Iin). If, as you say, the current maximum point occurs inside the coil, then the forward current and reflected current are in-phase inside the coil and the coil occupies much more of the antenna than ArcCos(Iout/Imax) I do believe a "Thank you very much" is in order. For your antenna, the calculated degrees that the coil occupies is within 1.5 degrees of the estimated degrees. -- 73, Cecil http://www.qsl.net/w5dxp -----= Posted via Newsfeeds.Com, Uncensored Usenet News =----- http://www.newsfeeds.com - The #1 Newsgroup Service in the World! -----== Over 100,000 Newsgroups - 19 Different Servers! =----- |
W4JLE wrote:
While I normally can see your point, even if I disagree with your conclusions. In this case Cecil, your just plain wrong! Would you mind telling me what I am wrong about? I presently have no clue. I freely admit to being wrong about what the stock market has done this year. Is that what you are talking about? -- 73, Cecil http://www.qsl.net/w5dxp -----= Posted via Newsfeeds.Com, Uncensored Usenet News =----- http://www.newsfeeds.com - The #1 Newsgroup Service in the World! -----== Over 100,000 Newsgroups - 19 Different Servers! =----- |
Richard Clark wrote,
On 31 Jan 2004 19:32:18 GMT, (Tdonaly) wrote: I have to eschew Gesundheit Thank you. |
Where do I begin...
To limit the universe, I disagree with the data referenced on your web page purporting to show how EZNEC got it wrong. Your just plain wrong. "Cecil Moore" wrote in message ... W4JLE wrote: While I normally can see your point, even if I disagree with your conclusions. In this case Cecil, your just plain wrong! Would you mind telling me what I am wrong about? I presently have no clue. I freely admit to being wrong about what the stock market has done this year. Is that what you are talking about? -- 73, Cecil http://www.qsl.net/w5dxp -----= Posted via Newsfeeds.Com, Uncensored Usenet News =----- http://www.newsfeeds.com - The #1 Newsgroup Service in the World! -----== Over 100,000 Newsgroups - 19 Different Servers! =----- |
W4JLE wrote:
Where do I begin... To limit the universe, I disagree with the data referenced on your web page purporting to show how EZNEC got it wrong. Your just plain wrong. I am not trying to be hardnosed about this. I am actually trying to be gentle about challenging someone's religion. If an inductive stub is properly modeled by EZNEC, why is an equivalent inductive coil not properly modeled? By properly modeled, I mean in agreement with reality. EZNEC assumes that the current travels through the lumped inductive reactance at faster than the speed of light. Why is it surprising to find out that doesn't match reality? What am I missing, besides religion based on math models? -- 73, Cecil http://www.qsl.net/w5dxp -----= Posted via Newsfeeds.Com, Uncensored Usenet News =----- http://www.newsfeeds.com - The #1 Newsgroup Service in the World! -----== Over 100,000 Newsgroups - 19 Different Servers! =----- |
Here's a post of mine from the thread titled 'colinear connundrum'
from a few years ago. Perhaps it will shed some light on the subject : Gray Frierson Haertig wrote: "One of the classic implementations of the collinear uses parallel resonant circuits as the phase inverting means between separate elements---." I`ve discussed the if and how a parallel resonant circuit can replace a short-circuit 1/4-wave stub as a phase inverter, and never been satisfied either. If considered as two terminal devices, a 1/4 wl stub, parallel resonant LC circuit and an insulator are equivalent, at least for steady state AC. Understanding the difference requires a slightly more elaborate model for the stub or LC circuit. The model must account for charge accumulation, or common mode current on the device. Classic network theory can be used if a third, or 'common mode center tap' is added to the device model. Consider the parallel resonant LC circuit with the center of the inductor (or capacitor) grounded. The impedance between the two 'hot' terminals will be very high as in the two terminal case. The ground connection introduces a new constraint. The voltage on a 'hot' terminal is now constrained to be equal in magnitude and of opposite polarity from the other 'hot' terminal. This is not the case for the two terminal device model. The three terminal device (center tap grounded) can be used as a polarity reversing 1:1 transformer by connecting one 'hot' terminal to a ground referenced source and driving a load with the other terminal. Of course the same effect could be accomplished without the capacitor if the center tapped inductor (autotransformer) had suitable properties. Note that if the two 'hot' terminals are shorted the impedance (common mode) to ground is zero. Observe: The differential mode impedance between 'hot' terminals is very high (ideally infinite). The common mode impedance to ground is zero. The voltage on the 'hot' terminals respect to ground is of equal magnitude and opposite polarity. But, as Gray noted, a perfect parallel resonant circuit is an insulator. So is the perfect short-circuit 1/4-wave stub. Now look at a 1/4 wl shorted stub far removed from ground. Viewed as a two terminal device it behaves similar to a parallel resonant LC circuit. If the two open 'hot' wires are shorted, the stub looks like a 1/4 wl long wire. The impedance with respect to ground is approximately 36 ohms, which is very small compared to the nearly infinite differential impedance. Think of it as a single 1/4 wl counterpoise; adding a second colinear 'radial' results in an even lower ( 36/2 ohms) 'virtual ground' impedance. Thus the 1/4 wl stub behaves similar to the parallel resonant LC circuit with the grounded center tap. The common mode behavior of the freespace 1/4 wl stub provides the low impedance 'virtual ground'. Of course suppressing the common mode resonance by coiling the transmission line or applying a common mode choke has the effect of inserting a high impedance in series with the 'ground' connection. In reality, the common mode impedance to ground of an isolated LC circuit is not infinite. Both the inductor and capacitor have capacitance to space which will provide some 'grounding' effect. At MF through VHF, the components would generally need to be physically very large to have a usefully low common mode impedance to ground however. The opposite terminals of the parallel resonant circuit and the opposite terminals of the short-circuit stub are out of phase, in either case. They are equivalent. Coupling between the elements exists in an ordinary dipole, even though the elements are end-to-end. There must be enough coupling to complete the transmission circuit, else the antenna wouldn`t work. Turns out the mutual impedance between two isolated colinear dipole elements is of the wrong polarity for parasitic operation as a broadside array. As you might expect, the mutual impedance between elements is dominated by end to end capacitance which is wrong for broadside gain. The Yagi configuration has a natural tendency to provide broadside gain, while the colinear does not. I think equivalence is the key. If one works, the other must work too. As long as they are truly equivalent for the case being considered. Failing to consider common mode impedances is unfortunately a very common practice and will often lead to incorrect conclusions. The devil is often in the details. bart wb6hqk |
Bart
I am just not smart enough to follow all of your post. But in between the lines I see a correlation to what I suggested that Cecil does to modify his collinear dipoles in the center portion a replacement circuit for a dimensionless inductance to a circuit that have dimensions in every sense and is its equal. However he has rejected this aproach. I would also add that if he imposed a parallel circuit that over lapped the dipole at each side then he has achieved an increased radiation efficiency per unit length since the parallel circuit radiation is additive to the dipole radiation.. That would replace a large portion of the center of a extended zepp and also eliminate the stub portion.which are basically inefficient. ( Cecil has also rejected this notion in the past prefering his multi stub length arrangement as shown on his page.) However, the idea of a combination loop dipole in this circle just apears to bring gasps of horror.as does the replacement of inefficient parts ( low efficiency portions or same that has counter phase radiation.) Since your post is laced with technical stuff that I don't understand but deals with the advantages of a loop over a stub, perhaps those that are more enlightened than I of which their are many, will discuss further your contribution so that education will replace the frustration that unfortunately now abounds Regards Art "Bart Rowlett" wrote in message om... Here's a post of mine from the thread titled 'colinear connundrum' from a few years ago. Perhaps it will shed some light on the subject : Gray Frierson Haertig wrote: "One of the classic implementations of the collinear uses parallel resonant circuits as the phase inverting means between separate elements---." I`ve discussed the if and how a parallel resonant circuit can replace a short-circuit 1/4-wave stub as a phase inverter, and never been satisfied either. If considered as two terminal devices, a 1/4 wl stub, parallel resonant LC circuit and an insulator are equivalent, at least for steady state AC. Understanding the difference requires a slightly more elaborate model for the stub or LC circuit. The model must account for charge accumulation, or common mode current on the device. Classic network theory can be used if a third, or 'common mode center tap' is added to the device model. Consider the parallel resonant LC circuit with the center of the inductor (or capacitor) grounded. The impedance between the two 'hot' terminals will be very high as in the two terminal case. The ground connection introduces a new constraint. The voltage on a 'hot' terminal is now constrained to be equal in magnitude and of opposite polarity from the other 'hot' terminal. This is not the case for the two terminal device model. The three terminal device (center tap grounded) can be used as a polarity reversing 1:1 transformer by connecting one 'hot' terminal to a ground referenced source and driving a load with the other terminal. Of course the same effect could be accomplished without the capacitor if the center tapped inductor (autotransformer) had suitable properties. Note that if the two 'hot' terminals are shorted the impedance (common mode) to ground is zero. Observe: The differential mode impedance between 'hot' terminals is very high (ideally infinite). The common mode impedance to ground is zero. The voltage on the 'hot' terminals respect to ground is of equal magnitude and opposite polarity. But, as Gray noted, a perfect parallel resonant circuit is an insulator. So is the perfect short-circuit 1/4-wave stub. Now look at a 1/4 wl shorted stub far removed from ground. Viewed as a two terminal device it behaves similar to a parallel resonant LC circuit. If the two open 'hot' wires are shorted, the stub looks like a 1/4 wl long wire. The impedance with respect to ground is approximately 36 ohms, which is very small compared to the nearly infinite differential impedance. Think of it as a single 1/4 wl counterpoise; adding a second colinear 'radial' results in an even lower ( 36/2 ohms) 'virtual ground' impedance. Thus the 1/4 wl stub behaves similar to the parallel resonant LC circuit with the grounded center tap. The common mode behavior of the freespace 1/4 wl stub provides the low impedance 'virtual ground'. Of course suppressing the common mode resonance by coiling the transmission line or applying a common mode choke has the effect of inserting a high impedance in series with the 'ground' connection. In reality, the common mode impedance to ground of an isolated LC circuit is not infinite. Both the inductor and capacitor have capacitance to space which will provide some 'grounding' effect. At MF through VHF, the components would generally need to be physically very large to have a usefully low common mode impedance to ground however. The opposite terminals of the parallel resonant circuit and the opposite terminals of the short-circuit stub are out of phase, in either case. They are equivalent. Coupling between the elements exists in an ordinary dipole, even though the elements are end-to-end. There must be enough coupling to complete the transmission circuit, else the antenna wouldn`t work. Turns out the mutual impedance between two isolated colinear dipole elements is of the wrong polarity for parasitic operation as a broadside array. As you might expect, the mutual impedance between elements is dominated by end to end capacitance which is wrong for broadside gain. The Yagi configuration has a natural tendency to provide broadside gain, while the colinear does not. I think equivalence is the key. If one works, the other must work too. As long as they are truly equivalent for the case being considered. Failing to consider common mode impedances is unfortunately a very common practice and will often lead to incorrect conclusions. The devil is often in the details. bart wb6hqk |
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