|
On Mon, 02 Feb 2004 14:12:54 -0600, Cecil Moore
wrote: doesn't even come close to answering the original question. It was a ****-ant question in the first place. |
Art Unwin KB9MZ wrote: Jim What is electrically smal and compared to what ?. I'm using the term in the same way one would use it to describe the length of an antenna - i.e. its physical length as opposed to its electrical length. As for the rest: I don't know about Cecil's underpinnings. ;-) 73, Jim AC6XG If one can make a small loop containing a small variable inductance as one would make a variable capacitive form which is what, 1/10 of a wave length and is inserted in Cecils drawing which is more than a wavelength long I would consider that relatively small. Since the circuit generated is purely from the constituents of the original inductance then the relatively small loop can be inserted. Knowing that the radiating surface is the inductance before it was reduced what is to stop inserting the small loop in a black box that has dimensions such that ports can be directly compared.? Cecil has stated that he is is confident that he is correctin his assertions ( and he may well be) he is not interested in counter proposals. Sort of reminds me that Bush also comes from Texas ! We therefore must accept what Cecil says as unreservidly correct.and there is nothing more to be said regarding the technical underpinnings. Either that or attack the man himself which cannot provide resolution. Regards Art "Jim Kelley" wrote in message ... Cecil Moore wrote: 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. It's certainly true that such a coil is not 'electrically' small. 73, Jim AC6XG |
Art Unwin KB9MZ wrote:
Cecil has stated that he is is confident that he is correct in his assertions ( and he may well be) he is not interested in counter proposals. Art, I'm not interested in counter proposals to reality. Reality is just fine the way it is. What I would really be interested in is an explanation of how a physically large coil, like a helical antenna, can cause a phase reversal in the absence of any ground reference, i.e. in free space. -- 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! =----- |
Jim Kelley wrote:
Do you mean physically small coils that are, naturally, also electrically small. Or do you mean physically small coils that are somehow electrically large? A grain of sand is physically large when it is in your eye but physically small under your foot. :-) Likewise, physically/ electrically small depends upon wavelength. -- 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:
wrote: doesn't even come close to answering the original question. It was a ****-ant question in the first place. Let's see - that's either sour grapes or sweet lemons - I can't remember which. -- 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! =----- |
Jim Kelley wrote:
Art Unwin KB9MZ wrote: Jim What is electrically small and compared to what ?. I'm using the term in the same way one would use it to describe the length of an antenna - i.e. its physical length as opposed to its electrical length. As for the rest: I don't know about Cecil's underpinnings. ;-) All I know is that every time there's a calculated or measured current taper through a coil, according to some experts, it's because the coil is not "physically small". :-) So where's the model for "physically large" coils? -- 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: Jim Kelley wrote: Do you mean physically small coils that are, naturally, also electrically small. Or do you mean physically small coils that are somehow electrically large? A grain of sand is physically large when it is in your eye but physically small under your foot. :-) Likewise, physically/ electrically small depends upon wavelength. Actually, that's not quite correct. In this context we are discussing whether something's size is small or large compared to a wavelength. Whether the wavelength is small or large compared to a grain of sand or your eye is irrelevant. :-) 73, Jim AC6XG |
On Mon, 02 Feb 2004 15:40:40 -0600, Cecil Moore
wrote: Richard Clark wrote: wrote: doesn't even come close to answering the original question. It was a ****-ant question in the first place. Let's see - that's either sour grapes or sweet lemons - I can't remember which. See? Even you can't tell the difference. |
Well we will have to be patient
Richard has a way to show it by virtue of the use of Eznec. I might add he is an expert with Eznec Having studied Meterology and microwaves. Tho I am not sure he has recognition of this by an acredited college and may well have got it on E bay, they have advanced degrees on most things on the net these days probably some for Shakespeare Olde English also.. Anyway there is really nothing more to be said on this subject until Richard comes up with the real goods on Eznec and use it where all others have failed.. Facts, all thereal facts. Still the thread had a good run as far as threads go as some one said and probably akin to sweeping up the streets in Pampalona to clean the bull**** left after the exciting run thru town. Yes some casualties among those that run with the bulls but exciting to watch. Best regards Art "Cecil Moore" wrote in message ... Art Unwin KB9MZ wrote: Cecil has stated that he is is confident that he is correct in his assertions ( and he may well be) he is not interested in counter proposals. Art, I'm not interested in counter proposals to reality. Reality is just fine the way it is. What I would really be interested in is an explanation of how a physically large coil, like a helical antenna, can cause a phase reversal in the absence of any ground reference, i.e. in free space. -- 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: All I know is that every time there's a calculated or measured current taper through a coil, according to some experts, it's because the coil is not "physically small". :-) So where's the model for "physically large" coils? I've also noted the use of that qualifier on several occasions in the discussion. There are apparently effects which become measureable as the inductors physical size begins to approach significant fractions of a wavelength. These affects appear to relate more to the impedance and radiation pattern of the antenna - first order affects as far as most here are concerned to be sure. On the other hand, if the coil is not physically small, then its probably not electrically small either. In other words it may comprise a significant fraction of the electrical length of the antenna. For a given inductance, a longer coil will require more turns than a shorter coil. The more turns, the greater the length of wire, and the greater the phase delay through the coil. A coil with shorter physical length, would require less wire and fewer turns to give the same inductance, and would give a shorter phase delay. 73, Jim AC6XG |
Richard Clark wrote:
wrote: Let's see - that's either sour grapes or sweet lemons - I can't remember which. See? Even you can't tell the difference. It depends upon whether you ate the lemons or not. :-) -- 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! =----- |
I can not believe what you are saying!
This thread is initiated by Wes not Yuri I have not read anywhere that Wes, and Roy and Yuri supports your position that Eznec can handle lumped loads in a real world situation. In fact I seem to remember that Yuri in the past stated that computor programs proffered by Tom who was using Eznec, did not reflect reality and was going to prove same with a series of experiments in the near future. Not only that Yuri has been off shore for most of this thread and has participated very little, prior to that he was under the weather. Now we come to the other person who you say supports you., Roy Roy has not participated in this thread started by Wes so where is that statement that his program Eznec can handle all the requirements placed on it by lumped loads. After you dissed him last week on another thread I can hardly believe he communicated privately with you regarding his program? Now we come to Wes...Wes is the originator of this thread which was a debate based on his modelling submission I do not recall him saying anything that supports your assertion. In fact when I looked at what he proffered on this thread I seem to remember that it reflected a radiating member of diameter equal to a real world coil into which was inserted a point, lumped load that was dimensionaless. I am sure he had good reason to do it that way but it certainly does not reflect a real world situation that Yuri, Cecil and I was looking for. Tho I must state firmly that only Wes 'walked the walk' in an effort to resolve a problem and deserves the thanks of all in trying to resolve it in one of many ways So I do not believe what you are saying and you are playing around with the word "truth" So now you have exposed yourself again for what you are, unless you can find in this thread or show that the associations with your statement regarding Eznec is true per private conversation or otherwise. I would be very curious if Roy supported your statement regarding Eznec and lumped loads, as would many of those who purchased his program which provided so many insights to antenna design. In fact I seem to remember a very clear statement by Roy saying his programs had no variable abilities which would be a requirement for real world analysis, however, I will leave him to speak for himself as his knoweledge regarding antennas and modeling is renown world wide. I have also showed all the posts that you made on this thread None of these provided facts , only opinions of yours that you have on other people, sarcastic in the main. Now I see that Cecil has brought up the subject directly with you and I urge every body to read them to ascertain what facts you are offering in return.or show how you avoid the issue as you have done many times in the past. My guess it will be the smear and run tactic that you off times use. So Richard ,gather the supporters you have specifically quoted so they can vouch for your assertions made with regard to Eznec and lumped loads to prove you are not the liar that your posting appear to suggest. Infact, if either Wes or Roy confirmes your "baloney" position statement I will supply a public apology to you since both of them hold my respect with regard to computor modeling. I still have vivid memories of where you argued for ages regarding contact fidelity where you pretty much said that contact pressure was everything and 'wipe' was nothing which is just laughable in industry but not apparently in the expert teaching of meterology in which you claim high education .. Well this time all posters will see what you are unless you can show otherwise.. You should never put people in a situation that they must accept what you say without prior permission. You have forced a burden upon them.by speaking for them knowing that they made no such statement.and have thus caused embarasment to them. Art Unwin KB9MZ....XG "Richard Clark" wrote in message ... On 1 Feb 2004 20:21:26 -0800, (Art Unwin KB9MZ) wrote: how Eznec can be manipulated into tackling the problem of replacing a non dimensional inductance to one that has physical dimensions so that all pertinent questions can be answered Art, It is clear that you write far more than you read. I did this already in a posting, in this thread: This may be found at: http://www.k3bu.us/loadingcoils.htm to which you responded: Obscure posting So clearly, even with the information offered, you lack the capacity to follow the rather simple instructions offered by 1.) Yuri, 2.) Roy, 3.) Myself that must've occupied all of two sentences. So to prove that it is baloney step forward with the facts which up to now you have not divulged. Art seeing it was YOUR claim, it is clearly baloney barring any demonstration from you (we should live so long) of its accuracy, irregardless of how 1.) Yuri, 2.) Roy, 3.) Myself offer solutions. What is more to the issue, is that it doesn't amount to 1dB difference, a fact that is clearly upheld by work outside of EZNEC by Wes. www.qsl.net/n7ws to which you responded: Nothing on that post So there you have it. Two sources, 4 individuals' work, and you have nothing to offer - still. You can at least let us know if you saw your shadow. If you cannot muster the facts to answer this, I see no reason to respond to your whining. 73's Richard Clark, KB7QHC |
On Tue, 03 Feb 2004 01:31:05 GMT, " Art Unwin KB9MZ"
wrote: I have not read anywhere that Wes, and Roy and Yuri That has been for your lack of reading. Thus I keep this to one line. |
Then you are what you have shown your self to be
And all can now see what you really are and can judge for themselves And they can also see how you avoided all things true when you refused to face the truth with Cecil and found a way to run away. Now show us how you can run away from yourself and your concience by hiding behind your own shadow. I am done with you because you represent nothing Art Unwin KB9MZ...XG "Richard Clark" wrote in message ... On Tue, 03 Feb 2004 01:31:05 GMT, " Art Unwin KB9MZ" wrote: I have not read anywhere that Wes, and Roy and Yuri That has been for your lack of reading. Thus I keep this to one line. |
Wes Stewart wrote:
I downloaded a couple of them, but I have a question. I opened them using MultiNEC, which reads all of the popular modeling program file formats. The loads did not import, but when I opened the same files in EZNEC 3 I saw them as R+jX loads with only an 'X' value. You can put in any R and XL value, Wes. The phase of the current will not change. The magnitude decreases and the phase stays the same. I learned from Dan, AC6LA, the author of MultiNEC, that some early EZNEC versions save all loads as Laplace and he doesn't read those into MultiNEC. Opening the files in EZNEC 3 and then just resaving them makes the import into MultiNEC work okay, but this makes me suspect that using your earlier files in my later version might be a problem. The documentaion says otherwise though, but to be sure, what are the actual load parameters. Well, your Laplace files won't run on my EZNEC version 2.0. They all come up as zeros. So I don't know what loads you used either. I don't want to comment further until I know exactly what you are using. You can vary R and XL values from zero to infinity. The phase of the current never changes. I tried values from 1+j300 to 1000+j300000 and it only affected the magnitude, not the phase. -- 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 Tue, 03 Feb 2004 03:39:42 GMT, " Art Unwin KB9MZ"
wrote: Then you are what you have shown your self to be And all can now see what you really are and can judge for themselves And they can also see how you avoided all things true when you refused to face the truth with Cecil and found a way to run away. Now show us how you can run away from yourself and your concience by hiding behind your own shadow. I am done with you because you represent nothing Art Unwin KB9MZ...XG Ah! Art, You are a po8 and don't know8 :-) |
On Mon, 02 Feb 2004 22:28:55 -0600, Cecil Moore
wrote: |Wes Stewart wrote: | I downloaded a couple of them, but I have a question. I opened them | using MultiNEC, which reads all of the popular modeling program file | formats. The loads did not import, but when I opened the same files | in EZNEC 3 I saw them as R+jX loads with only an 'X' value. | |You can put in any R and XL value, Wes. The phase of the current will |not change. The magnitude decreases and the phase stays the same. Okay, I guess that means the answer is: you used R+jX loads. | | I learned from Dan, AC6LA, the author of MultiNEC, that some early | EZNEC versions save all loads as Laplace and he doesn't read those | into MultiNEC. Opening the files in EZNEC 3 and then just resaving | them makes the import into MultiNEC work okay, but this makes me | suspect that using your earlier files in my later version might be a | problem. The documentaion says otherwise though, but to be sure, what | are the actual load parameters. | |Well, your Laplace files won't run on my EZNEC version 2.0. They all |come up as zeros. So I don't know what loads you used either. Mine aren't Laplace loads. There are straight RLC with C=0. | | I don't want to comment further until I know exactly what you are | using. | |You can vary R and XL values from zero to infinity. The phase of the |current never changes. I tried values from 1+j300 to 1000+j300000 |and it only affected the magnitude, not the phase. It remains to be seen in my mind whether you are correct in your assertions; however, I believe that you have stated that in your Kraus reference that he used the self-resonance of the inductors to do the magic. How on Earth can you expect a load consisting of only R and Xl to be self-resonant? |
Wes Stewart wrote:
Mine aren't Laplace loads. There are straight RLC with C=0. The 'LO' display says "Laplace Coefficients", "Select to show values", and the values are all zero. The feedpoint impedance of the antenna is infinite. I believe that you have stated that in your Kraus reference that he used the self-resonance of the inductors to do the magic. No magic - just relatively simple experiments. 1/2WL of a helical antenna reverses the phase of the current just like a 1/2WL wire does, over ground or in free space. How on Earth can you expect a load consisting of only R and Xl to be self-resonant? I *don't* expect such a coil to simulate reality. That's the whole problem. The artificial lumped load software doesn't match reality. It only approaches reality for "physically small" coils. Once again, a 75m Texas Bugcatcher coil is not physically small. -- 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, You might want to look at
http://web.ukonlineco.uk/g3ldo as there is quite a bit of interchange between various hams on measuring coils. It may give you some ideas for when the snow melts Regards Art "Yuri Blanarovich" wrote in message ... 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 |
Yuri, You might want to look at http://web.ukonlineco.uk/g3ldo as there is quite a bit of interchange between various hams on measuring coils. It may give you some ideas for when the snow melts Regards Art that link don't worky |
Cecil Moore wrote in message
I *don't* expect such a coil to simulate reality. That's the whole problem. The artificial lumped load software doesn't match reality. It only approaches reality for "physically small" coils. Once again, a 75m Texas Bugcatcher coil is not physically small. It's physically small enough that any error should be small. IE: 1 db or less. This has been shown a few times. Myself, I don't lose much sleep over the phasing coil dilemma. I don't think it will be much of an issue when modeling simple short loaded whips. Being there is a workaround for phasing antennas, IE: separate sources where you can define the phase angle, the antenna can still be modeled. There is something that keeps bothering me and my beady mind though... You say the current going "one way" will be fairly constant across the coil. Will the coil position effect this? If not, that creates a new problem. If the coil position does not effect the current taper going "one way", I don't see how it would coming back the other way. Regardless of coil position. If the current is constant going one way, seems to me it would also be constant the other way. So in effect, they would cancel each other out, and would still be fairly constant. I guess what I want to see is experiments to test your theory of coil position effecting the current taper. IE: You claim a center load would have constant current, but off center would not. Seems to me, if this is true, there should be a position that places maximum current at the top of the coil, not bottom. If you never see this, I would be suspect. Well, back to my 1 db or less rubber room... MK |
Mark Keith wrote:
Cecil Moore wrote in message I *don't* expect such a coil to simulate reality. That's the whole problem. The artificial lumped load software doesn't match reality. It only approaches reality for "physically small" coils. Once again, a 75m Texas Bugcatcher coil is not physically small. It's physically small enough that any error should be small. IE: 1 db or less. A 13% error is small? The error is even larger than that for the current at the top of the coil. If the coil position does not effect the current taper going "one way", I don't see how it would coming back the other way. Regardless of coil position. The forward current and reflected current phasors rotate in opposite directions. Sometimes they are in phase and sometimes they are out of phase. In a lossless transmission line, the forward current and reflected current are absolutely constant with zero taper. Yet they still result in standing waves with minimum and maximum points. This is explained on my web page. Seems to me, if this is true, there should be a position that places maximum current at the top of the coil, not bottom. I have already said multiple times, depending upon where the coil is placed, the net current into the coil can be less than, equal to, or greater than the net current coming out. It all depends upon the phasor sum of the forward current and reflected current. It can be zero or maximum or anything in between depending upon where the coil is placed. For Kraus' phase-reversing coil, the net current is zero at both ends and maximum in the middle of the coil. -- 73, Cecil http://www.qsl.net/w5dxp/current.htm -----= 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! =----- |
Sorry about that, missed the period before co
http://web.ukonline.co.uk/g3ldo Art "Yuri Blanarovich" wrote in message ... Yuri, You might want to look at http://web.ukonlineco.uk/g3ldo as there is quite a bit of interchange between various hams on measuring coils. It may give you some ideas for when the snow melts Regards Art that link don't worky |
Cecil Moore wrote in message ...
Mark Keith wrote: Cecil Moore wrote in message I *don't* expect such a coil to simulate reality. That's the whole problem. The artificial lumped load software doesn't match reality. It only approaches reality for "physically small" coils. Once again, a 75m Texas Bugcatcher coil is not physically small. It's physically small enough that any error should be small. IE: 1 db or less. A 13% error is small? The error is even larger than that for the current at the top of the coil. I don't know where this 13% comes from, but how many db difference would it make in the modeling results? I bet it's about 1 or less. If you have an 8 ft antenna, with a 1 ft tall coil, no matter what the current taper is across the coil, it will not drastically effect the modeling results. At least 3 or 4 people have shown this. The coil is not a large enough portion of the overall antenna. And any taper of the current along that one foot section is not going to make a difference more than about 1 db. Usually less. Seems to me, if this is true, there should be a position that places maximum current at the top of the coil, not bottom. I have already said multiple times, depending upon where the coil is placed, the net current into the coil can be less than, equal to, or greater than the net current coming out. It all depends upon the phasor sum of the forward current and reflected current. It can be zero or maximum or anything in between depending upon where the coil is placed. For Kraus' phase-reversing coil, the net current is zero at both ends and maximum in the middle of the coil. I know you have said it multiple times, but so far I don't recollect anyone actually measuring a real world coil, and finding max current at the top of the coil. That is what is bothering me. MK |
Cecil Moore wrote: I have already said multiple times, depending upon where the coil is placed, the net current into the coil can be less than, equal to, or greater than the net current coming out. Which end of the coil is the input and which end is the output? 73, Jim AC6XG |
Mark Keith wrote:
Cecil Moore wrote: A 13% error is small? The error is even larger than that for the current at the top of the coil. I don't know where this 13% comes from, but how many db difference would it make in the modeling results? Uh Mark, 1 dB error = 13% error 10^(0.1) = 1.26 2 dB error = 29% error 10^(0.2) = 1.58 3 dB error = 50% error 10^(0.3) = 2.00 I know you have said it multiple times, but so far I don't recollect anyone actually measuring a real world coil, and finding max current at the top of the coil. That is what is bothering me. MK Nobody builds an antenna that way but consider the following monopole. Ground is at the left, top is at the right. Each of the following 1/4WL sections are electrical 1/4WL's. 1/4WL coil Gnd-FP------1/4WL tubing------//////////------1/4WL stinger------ max--*-------------------------------*------------------------- * * * * * * Current min-------------------*----------------------------------* The current at the feedpoint will be high. The current at the bottom of the coil will be low. The current at the top of the coil will be high. The current at the tip of the antenna will be low. -- 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! =----- |
Jim Kelley wrote:
Cecil Moore wrote: I have already said multiple times, depending upon where the coil is placed, the net current into the coil can be less than, equal to, or greater than the net current coming out. Which end of the coil is the input and which end is the output? The DC model strikes again. For AC, current flows out of the coil input just as often as it flows in and into the coil output just as often as it flows out. :-) But by convention the 'input' of the coil is the end closest to the antenna feedpoint. -- 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! =----- |
Mark wrote in reply to Cecil, (snip) I have already said multiple times, depending upon where the coil is placed, the net current into the coil can be less than, equal to, or greater than the net current coming out. It all depends upon the phasor sum of the forward current and reflected current. It can be zero or maximum or anything in between depending upon where the coil is placed. For Kraus' phase-reversing coil, the net current is zero at both ends and maximum in the middle of the coil. I know you have said it multiple times, but so far I don't recollect anyone actually measuring a real world coil, and finding max current at the top of the coil. That is what is bothering me. MK Hi Mark, Cecil doesn't actually have to measure anything, since he's already convinced he's right because his arguments agree with the theory he made up in his head. Yuri is supposed to measure loading coils using fish tank thermometers and such. The real test will be when someone tries to make a new, improved antenna based on the belief that the current taper on the loading coil of a physically short antenna makes a tinker's damn worth of difference in the far field radiation of said antenna. 73, Tom Donaly, KA6RUH |
Cecil Moore wrote: Jim Kelley wrote: Cecil Moore wrote: I have already said multiple times, depending upon where the coil is placed, the net current into the coil can be less than, equal to, or greater than the net current coming out. Which end of the coil is the input and which end is the output? The DC model strikes again. A poor craftsman always blames his tools. But by convention the 'input' of the coil is the end closest to the antenna feedpoint. And so what you're saying is that by convention RF current flows "in" to one end, and then "out" of the other? I must admit I don't like the sound of that one bit. Sounds like you're describing the direction a "wave" is "traveling", when we know that the "wave" is really just "standing" there. :-) 73, Jim AC6XG |
Tdonaly wrote:
Mark wrote in reply to Cecil, I know you have said it multiple times, but so far I don't recollect anyone actually measuring a real world coil, and finding max current at the top of the coil. That is what is bothering me. MK Cecil doesn't actually have to measure anything, since he's already convinced he's right because his arguments agree with the theory he made up in his head. Well, just so you guys can understand what I am talking about, here is an EZNEC file that clearly demonstrates low current at the bottom of the coil and high current at the top of the coil. http://www.qsl.net/w5dxp/sqcoil.ez The real test will be when someone tries to make a new, improved antenna based on the belief that the current taper on the loading coil of a physically short antenna makes a tinker's damn worth of difference in the far field radiation of said antenna. Nice try, but that's just a copout diversion because the far field radiation is irrelevant to the argument over current through a loading 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! =----- |
Jim Kelley wrote:
And so what you're saying is that by convention RF current flows "in" to one end, and then "out" of the other? Yes, that's the DC convention adopted to AC. Just be sure to put a dot on the input side so everyone will know it's the input reference. :-) That convention also applies to baluns and transformers. I must admit I don't like the sound of that one bit. Sounds like you're describing the direction a "wave" is "traveling", when we know that the "wave" is really just "standing" there. :-) I didn't invent the 'AC current flowing away from the source' convention but most of the tools and concepts that I was taught assume such. It would be extremely difficult to introduce a new and different convention. -- 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:
The real test will be when someone tries to make a new, improved antenna based on the belief that the current taper on the loading coil of a physically short antenna makes a tinker's damn worth of difference in the far field radiation of said antenna. That's right. Cavemen didn't need to understand fire in order to make fire. They knew everything they needed to know about it. In fact, fire has not changed one iota with the advent of modern science. |
Cecil Moore wrote: Jim Kelley wrote: And so what you're saying is that by convention RF current flows "in" to one end, and then "out" of the other? Yes, that's the DC convention adopted to AC. Just be sure to put a dot on the input side so everyone will know it's the input reference. :-) That convention also applies to baluns and transformers. The dot indicates phase polarity. I must admit I don't like the sound of that one bit. Sounds like you're describing the direction a "wave" is "traveling", when we know that the "wave" is really just "standing" there. :-) I didn't invent the 'AC current flowing away from the source' convention but most of the tools and concepts that I was taught assume such. Maybe they taught this "convention" in grade school back in the '40's? I don't know what application it might have here. Maybe you could point to somewhere in 95-1 where they make use of this "convention". Or indicate how it might apply to a coil having alternating current going "in" from both ends. 73, Jim AC6XG |
Tdonaly wrote:
Cecil doesn't actually have to measure anything, since he's already convinced he's right because his arguments agree with the theory he made up in his head. Forgot to post the accompanying graphic which is: http://www.qsl.net/w5dxp/sqcoil.gif How do you explain that current distribution with current minimum at the bottom of the coil and current maximum at the top of 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! =----- |
Jim Kelley wrote:
The dot indicates phase polarity. A necessity when using DC models for AC circuits. Hint: Balanced AC has no objective fixed polarity. It is all subjective. (Never mind that current holes flow out of the '+' terminal of a battery. :-) Maybe they taught this "convention" in grade school back in the '40's? I don't know what application it might have here. Maybe you could point to somewhere in 95-1 where they make use of this "convention". Or indicate how it might apply to a coil having alternating current going "in" from both ends. If you want to see current flowing out of both ends of a coil at the same time just run http://www.qsl.net/w5dxp/sqcoil.ez at 29 MHz. Current into the bottom of the coil has a phase angle of -174 degrees, i.e. referenced to the source, it is flowing toward the source. How could it be otherwise? That point is ~1/2WL away from the source. Current out of the top of the coil has a phase angle of -6 degrees, i.e. referenced to the source, it is flowing away from the source. How could it be otherwise? That point is ~1WL away from the source. If you play with the parameters, I'm sure you can shift that -174 degrees to -180 degrees and that -6 degrees to zero 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! =----- |
Cecil,
I was just trying to help keep you from sounding like an idiot. Never mind. I'll stop. Jim Cecil Moore wrote: Jim Kelley wrote: The dot indicates phase polarity. A necessity when using DC models for AC circuits. Hint: Balanced AC has no objective fixed polarity. It is all subjective. (Never mind that current holes flow out of the '+' terminal of a battery. :-) Maybe they taught this "convention" in grade school back in the '40's? I don't know what application it might have here. Maybe you could point to somewhere in 95-1 where they make use of this "convention". Or indicate how it might apply to a coil having alternating current going "in" from both ends. If you want to see current flowing out of both ends of a coil at the same time just run http://www.qsl.net/w5dxp/sqcoil.ez at 29 MHz. Current into the bottom of the coil has a phase angle of -174 degrees, i.e. referenced to the source, it is flowing toward the source. How could it be otherwise? That point is ~1/2WL away from the source. Current out of the top of the coil has a phase angle of -6 degrees, i.e. referenced to the source, it is flowing away from the source. How could it be otherwise? That point is ~1WL away from the source. If you play with the parameters, I'm sure you can shift that -174 degrees to -180 degrees and that -6 degrees to zero 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! =----- |
Cecil wrote,
Tdonaly wrote: Cecil doesn't actually have to measure anything, since he's already convinced he's right because his arguments agree with the theory he made up in his head. Forgot to post the accompanying graphic which is: http://www.qsl.net/w5dxp/sqcoil.gif How do you explain that current distribution with current minimum at the bottom of the coil and current maximum at the top of the coil? -- 73, Cecil http://www.qsl.net/w5dxp That's a neat picture, Cecil. How did you make the picture of the coil? Of course, you can do the same thing with a coil, *or a capacitor* and a couple of identical tank circuits. Actually, why make them either in or out of phase? That's boring. You can make the phase across the inductor/capacitor any value you want between 180 and minus 180 just by varying the frequency. Check out the currents in the tank circuits when they're 90 degrees out of phase with one another. The length of a capacitor is very small, Cecil. How do expect something that small to be able to change the current between two tank circuits 180 degrees? 73, Tom Donaly, KA6RUH |
On Wed, 04 Feb 2004 13:28:38 -0600, Cecil Moore
wrote: the far field radiation is irrelevant to [renders] the argument over current through a loading coil [a ****-ant argument] |
Cecil
Seems like the model is lacking in all the details and frankly I feel I am looking at an intentianal sham for some reason For instance you do not show coupling to ground which is why I am suspicious since resonance is unavoidably affected by nearby objects as well as ground I f you drew your model the same way you portray your G5RV or Zepp type dipole to accomodate the loss of coupling to ground I would feel a lot better. You also have not specified a a frequency of use that is also conspiciuos now I have been moved to a suspicious aproach especially when you interchange wavelength and size of inductance at the same time ignoring the coupling effects of said items which affect phase change..Plus ignors the radiation effect even tho it may be self cancelling since you show it as zero length ! Methinks I have to study the model more for a troubling omission like the addition of a inductance that is dimensionless and large compared to a model that ignores factors such as coupling.and the like. No disrespect intended Regards Art Art "Cecil Moore" wrote in message ... Tdonaly wrote: Mark wrote in reply to Cecil, I know you have said it multiple times, but so far I don't recollect anyone actually measuring a real world coil, and finding max current at the top of the coil. That is what is bothering me. MK Cecil doesn't actually have to measure anything, since he's already convinced he's right because his arguments agree with the theory he made up in his head. Well, just so you guys can understand what I am talking about, here is an EZNEC file that clearly demonstrates low current at the bottom of the coil and high current at the top of the coil. http://www.qsl.net/w5dxp/sqcoil.ez The real test will be when someone tries to make a new, improved antenna based on the belief that the current taper on the loading coil of a physically short antenna makes a tinker's damn worth of difference in the far field radiation of said antenna. Nice try, but that's just a copout diversion because the far field radiation is irrelevant to the argument over current through a loading 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! =----- |
Jim Kelley wrote:
I was just trying to help keep you from sounding like an idiot. The math model seduction is apparently worse than I thought. If you are talking about my assertion that phase and direction of current flow are related, I suggest you demonstrate 0+j0.5 amps of current and tell us which of the two possible directions in a transmission line that imaginary current is flowing. So you disagree that 1 amp at 180 degrees is flowing in the opposite direction to 1 amp at zero degrees? If not, why do you disagree that 1 amp at 170 degrees is flowing in the opposite direction of 1 amp at 10 degrees? The direction of current flow is the cosine of the phase angle. -- 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! =----- |
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