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As an engineer, I have taken all the courses to make me as smart as I need
to be, right? No, not a chance. Here I sit, stupified, not even knowing which variables to put in a formula. To be found: How far will I get into a newsgroup thread before it degenerates into name calling, circular reasoning, begging the question, etc. Maxwell never dreamed of this. |
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Sal M. Onella wrote:
[...] plonk ... JS |
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I find that there are many anomalies in RF theory. For example, Maxwells
Equations show reflection at a boundary where current flows in the metal surface down to the skin depth. Books then state that this boundary condition applies to waves guided by two wires. The wires therefore sort of reflect the wave and guide it. Power flows as the Poynting vector. Current can be a flow of electrons or holes. If the current in a P type semiconductor is holes, it is a flow of emptiness or nothing. Current is normally said to be the flow of electrons. The electrons actually move very slowly with a drift velocity of a few mm per second. The signal part of the current that flows near speed of light is the electromagnetic wave that flows in the area outside the conductor. There seem to be a number of disputes in RF e.g. about the effectiveness of conjugate matching with Walter Maxwell refuting articles in his book "Reflections". RF seems to be a black art e.g. when it comes to S parameters, network analysers, phase matching and batch matching of cables. Little seems to be written down. |
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The problems you're encountering are the result of trying to
oversimplify electromagnetic theory by reducing it to conceptual models which are far from adequate. Your basic conceptual models are faulty, so any conclusions you draw from using these models will eventually lead to contradictions. That same problem has, in fact, been the cause of a huge number of argumentative postings on this newsgroup. You have a great deal of curiosity about electromagnetic phenomena, so you'd benefit a great deal from a bit of education. To fully understand electromagnetics, you need a solid background in mathematics. Without the solid background of math and electromagnetic theory, you'll always find it necessary to use oversimplified models, and those will always lead to contradictions. It takes considerable time and effort to gain the necessary background, but if you truly want the answers to your questions, it's the only way. Roy Lewallen, W7EL David wrote: I find that there are many anomalies in RF theory. For example, Maxwells Equations show reflection at a boundary where current flows in the metal surface down to the skin depth. Books then state that this boundary condition applies to waves guided by two wires. The wires therefore sort of reflect the wave and guide it. Power flows as the Poynting vector. Current can be a flow of electrons or holes. If the current in a P type semiconductor is holes, it is a flow of emptiness or nothing. Current is normally said to be the flow of electrons. The electrons actually move very slowly with a drift velocity of a few mm per second. The signal part of the current that flows near speed of light is the electromagnetic wave that flows in the area outside the conductor. There seem to be a number of disputes in RF e.g. about the effectiveness of conjugate matching with Walter Maxwell refuting articles in his book "Reflections". RF seems to be a black art e.g. when it comes to S parameters, network analysers, phase matching and batch matching of cables. Little seems to be written down. |
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In article , Roy Lewallen
wrote: The problems you're encountering are the result of trying to oversimplify electromagnetic theory by reducing it to conceptual models which are far from adequate. Your basic conceptual models are faulty, so any conclusions you draw from using these models will eventually lead to contradictions. That same problem has, in fact, been the cause of a huge number of argumentative postings on this newsgroup. snip Well stated, Roy. I suspect the majority of hams are not degreed EEs that have delved into elementary electromagnetic theory (It was the least popular EE course when I was an undergrad.) Of course you don't need an in-depth understanding to get on the air. The problem, as you point out, arises when folks start going beyond the "practical" and hobby aspects (e.g. beyond the scope of the ARRL handbooks) by providing explanations of phenomena that are not supported by electromagnetic theory as embodied in Maxell's equations. Then there's a university EE professor who should know the theory and ends up supporting misguided concepts like the crossed-field antenna (CFA). Sincerely, and 73s from N4GGO, John Wood (Code 5550) e-mail: Naval Research Laboratory 4555 Overlook Avenue, SW Washington, DC 20375-5337 |
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Then there's a university EE professor who should know the theory and ends up supporting misguided concepts like the crossed-field antenna (CFA). Sincerely, and 73s from N4GGO, And then there is our fractal boy - who thankfully has morphed into shilling gullible governmental and commercial purchasing agents.. denny |
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J. B. Wood wrote:
Then there's a university EE professor who should know the theory and ends up supporting misguided concepts like the crossed-field antenna (CFA). Then there are the people on this newsgroup who presuppose that the lumped circuit model is adequate for analyzing 75m Texas Bugcatcher coils. -- 73, Cecil http://www.w5dxp.com |
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The Elite rising still aye , as a hobby or not , what i know is if there
is enough spark no matter what , it sparks no matter what...... Quantify that... and that is a sarcastik knock ... Great minds that no know of the Alien... Positive about being Negative P. "J. B. Wood" wrote in message ... In article , Roy Lewallen wrote: The problems you're encountering are the result of trying to oversimplify electromagnetic theory by reducing it to conceptual models which are far from adequate. Your basic conceptual models are faulty, so any conclusions you draw from using these models will eventually lead to contradictions. That same problem has, in fact, been the cause of a huge number of argumentative postings on this newsgroup. snip Well stated, Roy. I suspect the majority of hams are not degreed EEs that have delved into elementary electromagnetic theory (It was the least popular EE course when I was an undergrad.) Of course you don't need an in-depth understanding to get on the air. The problem, as you point out, arises when folks start going beyond the "practical" and hobby aspects (e.g. beyond the scope of the ARRL handbooks) by providing explanations of phenomena that are not supported by electromagnetic theory as embodied in Maxell's equations. Then there's a university EE professor who should know the theory and ends up supporting misguided concepts like the crossed-field antenna (CFA). Sincerely, and 73s from N4GGO, John Wood (Code 5550) e-mail: Naval Research Laboratory 4555 Overlook Avenue, SW Washington, DC 20375-5337 |
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On 2 May, 04:13, (J. B. Wood) wrote:
In article , Roy Lewallen wrote: The problems you're encountering are the result of trying to oversimplify electromagnetic theory by reducing it to conceptual models which are far from adequate. Your basic conceptual models are faulty, so any conclusions you draw from using these models will eventually lead to contradictions. That same problem has, in fact, been the cause of a huge number of argumentative postings on this newsgroup. snip Well stated, Roy. I suspect the majority of hams are not degreed EEs that have delved into elementary electromagnetic theory (It was the least popular EE course when I was an undergrad.) Of course you don't need an in-depth understanding to get on the air. The problem, as you point out, arises when folks start going beyond the "practical" and hobby aspects (e.g. beyond the scope of the ARRL handbooks) by providing explanations of phenomena that are not supported by electromagnetic theory as embodied in Maxell's equations. snip Hmmmmm! Then how do you account for the broad rejection from "EE"s of Gaussian antennas that comply and are supported by electromagnetic theory as embodied in Maxwells equations ? As you put your address as the "Naval Research Laboratory" where would you place the responsability for rejection? Personaly I would place it in the syndrome of " Not invented at my place" which always trumps the pursuit of pure science. You are not alone ofcourse, as even esteemed institutions such as Nasa and Universities follow the same regimen since their concerns are with their own pockets rather than science for itself. I read the other day that antenna design was holding up what appears to be tremendous advances in science especially in the science of communications. Yet derision is placed at the feet of the inventors of many antenna theories for having the temerity of challenging the "all is known" attitudes where curiousity should have always reigned. Art. , John Wood (Code 5550) e-mail: Naval Research Laboratory 4555 Overlook Avenue, SW Washington, DC 20375-5337 |
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On 2 May, 06:23, Cecil Moore wrote:
J. B. Wood wrote: Then there's a university EE professor who should know the theory and ends up supporting misguided concepts like the crossed-field antenna (CFA). Then there are the people on this newsgroup who presuppose that the lumped circuit model is adequate for analyzing 75m Texas Bugcatcher coils. -- 73, Cecil http://www.w5dxp.com Cecil, the interest in this group is what is incorrect not what is correct. There is many a poster you is willing to deride but very few that stand up for reasons why. Why else would one have a thread on a problem that over 300 posts were made that does not finish with an orderly solution.? It is because derision overcomes reasonable thought. I suspect that the CFA situation continues because most are resting on empirical results where as an in depth study using known principles may well provide answers both good and bad but does not take place because of resistance to change and 'all is known' And ofcourse there is that famous fighting cry of the couch potato who states it is not my job demanding solutions must be brought to him. Art .. Art |
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In article om, art
wrote: Hmmmmm! Then how do you account for the broad rejection from "EE"s of Gaussian antennas that comply and are supported by electromagnetic theory as embodied in Maxwells equations ? As you put your address as the "Naval Research Laboratory" where would you place the responsability for rejection? Personaly I would place it in the syndrome of " Not invented at my place" Well, you're entitled to your opinion, Art. I have no experience with "Gaussian antennas." If these antennas have been the subject of, say IEEE papers my guess would be that they are worthy of investigation. In the case of the CFA, cold fusion or anything else for that matter, extraordinary claims require extraordinary evidence. IOW anyone can believe anything they want. The problem is in getting others to believe it. And when it comes to skeptical scientists/physicists/engineers that ain't easy. However, the truth more often than not emerges at some point. Sincerely, John Wood (Code 5550) e-mail: Naval Research Laboratory 4555 Overlook Avenue, SW Washington, DC 20375-5337 |
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On May 2, 5:23 pm, (J. B. Wood) wrote:
In the case of the CFA, cold fusion or anything else for that matter, extraordinary claims require extraordinary evidence. Most of us would be happy with just ordinary evidence: bigfoot - a specimen, or some bones. Just the normal stuff. paranormal - just a repeatable controlled experiment cold fusion - just a repeatable controlled experiment CFA - the same Not anecdote, however. That never counts. ....Keith |
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On 2 May, 15:47, Keith Dysart wrote:
On May 2, 5:23 pm, (J. B. Wood) wrote: In the case of the CFA, cold fusion or anything else for that matter, extraordinary claims require extraordinary evidence. Most of us would be happy with just ordinary evidence: bigfoot - a specimen, or some bones. Just the normal stuff. paranormal - just a repeatable controlled experiment cold fusion - just a repeatable controlled experiment CFA - the same Not anecdote, however. That never counts. ...Keith No Kieth that is not true. A month ago we had a Doctor from MIT who gave a descision on this newsgroup with respect to the Maxwells law. He made an mathematical analysis of an antenna that complied via mathematics. Only one person agreed with his analysis. All others on this newsgroup denied the existance of this analysis as "proof". The Doctor gave an analysis of a conservative field that was transformed to a non concervative field by the addition of a unit of time. In that case it was a Gaussian field that followed Gaussian law and the Doctor showed by the addition of time to a conservative field it complied with Maxwells laws by changing to a non conservative field that allowed for a design of a radiating array of maximum efficiency. I also saw it as an explanational truth of Poyntings Vector. We have many different types of experts on this newsgroup and all but one person dissed the idea of conformaty to Maxwell. So something simple is not want this group wants it is something to diss and degenerate. As J B Wood stated the truth eventually will come out, but it will not be via this newsgroup. By the way, there was nobody except one familiar enough with Maxwells laws to mount a professional response and many who one would have assumed had the required knoweledge either dissed or stayed quiet to stay on the safe side. Art |
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On May 2, 7:23 am, Cecil Moore wrote:
J. B. Wood wrote: Then there's a university EE professor who should know the theory and ends up supporting misguided concepts like the crossed-field antenna (CFA). Then there are the people on this newsgroup who presuppose that the lumped circuit model is adequate for analyzing 75m Texas Bugcatcher coils. -- 73, Cecil http://www.w5dxp.com Well, it is, as far as designing the antenna. What advantage would knowing about any current "taper" give you? None that I can see. The design of the antenna will still end up the same, either way you go about it. The loading coil will still be at the same height, which is more a practical and mechanical problem, rather than considering any taper of current across the coil. To me, this is one of those things that might be handy to consider, maybe more for designing very complex loaded antennas, ?? but not the run of the mill bugcatcher. Even with complex arrays, I'm not sure if it would help you too much. I'd be surprised if any increase of gain from applying this knowledge would exceed 1 db. Than I'd have to ask...How *would* you apply this knowledge. I'm not trying to be a party pooper, but I don't see much advantage in considering current taper across a short lumped coil. I'm still going to mount my coils in the same places, which is generally as high as I can get them. I'm more worried about current distribution across the whole whip, than I am the short coil alone. MK |
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On May 2, 12:06 pm, art wrote:
On 2 May, 04:13, (J. B. Wood) wrote: Then how do you account for the broad rejection from "EE"s of Gaussian antennas that comply and are supported by electromagnetic theory as embodied in Maxwells equations ? It's fairly simple from my point of view.. You talk a bunch of jibber- jabber that really doesn't make a whole lot of sense, and you seem to refuse to want to build and test an actual antenna. Talk is cheap to me. I want to see one in the air, live, and working. Compare it to a known reference like a 1/2 dipole and let the chips fall where they may. Then you have something to actually talk about. MK |
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On 3 May, 10:41, wrote:
On May 2, 12:06 pm, art wrote: On 2 May, 04:13, (J. B. Wood) wrote: Then how do you account for the broad rejection from "EE"s of Gaussian antennas that comply and are supported by electromagnetic theory as embodied in Maxwells equations ? It's fairly simple from my point of view.. You talk a bunch of jibber- jabber that really doesn't make a whole lot of sense, and you seem to refuse to want to build and test an actual antenna. Talk is cheap to me. I want to see one in the air, live, and working. Compare it to a known reference like a 1/2 dipole and let the chips fall where they may. Then you have something to actually talk about. MK I was referring to 'EE's not " HS "graduates ! It is certainly understandable from those who are not familiar with the arts. You can only get so far with a general understanding but it has been said on this newsgroup by others that without a full understanding of the concepts you finish up with lots of misconceptions, and that seems to make makes sense when I read your postings. .. I suggest you keep quiet and wait until you can buy one then you are less likely to screw up. It is not a design for a typical couch expert to expound upon. Suggest you wait until you can quote from a book if you want to impress |
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On 3 May, 11:27, Cecil Moore wrote:
wrote: What advantage would knowing about any current "taper" give you? The advantage of understanding reality. In the following example: Source------------A-//////////-B---------------- wire coil wire The current at A is measured to be zero. The current at B is measured to be one amp. Does it mean that there is an unknown source of energy magically entering the coil from the outside world? Of course not. It just means that we are dealing with standing-wave current and we cannot even tell which way its phasor is rotating. It just means that the forward traveling current and reflected traveling current are of equal magnitude and opposite phase at point A. They are not of opposite phase at point B. The traveling wave phase shift through the coil explains everything. No need for any lumped circuit magic. No need for a magic source of extra energy. A distributed network analysis is all one needs. -- 73, Cecil, w5dxp.com Cecil, can't you make one and send it to him or better still send him a picture ?. Words and sentences are not his forte |
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Cecil Moore wrote:
wrote: What advantage would knowing about any current "taper" give you? The advantage of understanding reality. In the following example: Source------------A-//////////-B---------------- wire coil wire The current at A is measured to be zero. The current at B is measured to be one amp. Does it mean that there is an unknown source of energy magically entering the coil from the outside world? Of course not. It just means that we are dealing with standing-wave current and we cannot even tell which way its phasor is rotating. The only thing GIVEN was the magnitude of the standing wave current. A directional coupler would obviously produce a different reading at those points. It just means that the forward traveling current and reflected traveling current are of equal magnitude and opposite phase at point A. They are not of opposite phase at point B. The traveling wave phase shift through the coil explains everything. So the only thing which remains to be explained is the "traveling wave phase shift through the coil". No need for any lumped circuit magic. No need for a magic source of extra energy. A distributed network analysis is all one needs. The difference between the item marked "coil" in your drawing, and a lump, is that one is marked "coil". 73, Jim AC6XG |
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Roy Lewallen wrote:
wrote: Well, it is, as far as designing the antenna. . . MK And MK takes the bait, hook, line, and sinker. The fight is on, and the fish will be played until he can't so much as wiggle a fin. . . Roy Lewallen, W7EL Do fish have phasors? If so, then we know that they must keep rotating. Of course we can't figure out which direction they are rotating, but at least the spin continues. 73, Gene W4SZ |
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Roy Lewallen wrote:
And MK takes the bait, hook, line, and sinker. Actually, the hook, line, and sinker that was swallowed years ago is that a 360 cubic inch 75m Texas Bugcatcher coil can be magically shrunken down to a dimensionless point inductance that passes current with a zero delay and phase shift, i.e. faster than the speed of light. The technical truth will triumph in the end. A 75m Texas Bugcatcher coil occupies ~30 degrees of a 75m mobile antenna and it takes the forward current (and reflected current) ~21 nS to flow through the coil. -- 73, Cecil http://www.w5dxp.com |
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art wrote: I was referring to 'EE's not " HS "graduates ! It is certainly understandable from those who are not familiar with the arts. You can only get so far with a general understanding but it has been said on this newsgroup by others that without a full understanding of the concepts you finish up with lots of misconceptions, and that seems to make makes sense when I read your postings. Are you an EE? Seems to me you were some type of mechanical engineer. If so, I don't see how your qualifications are a heck of a lot greater than mine. How would you describe your level of understanding? General? High? Massive? Einsteins lost step child? I could guess, but I'll reserve comment.. What misconceptions have I finished up with lately? Can you list them? I'd be glad to go back and review any I'm not aware of. . I suggest you keep quiet and wait until you can buy one then you are less likely to screw up. Why would I want to buy a gaussian antenna? I have no real use for one that I can think of. Besides, I don't generally waste money on antennas. It is not a design for a typical couch expert to expound upon. I've never been able to gather enough coherant details to expound on it, even if I wanted to. Also, I don't sit on a couch. There is one in the other room, but I'm never in there. I sit in a rollaround office chair, which hurts my ass in general. Needs more cushioning. A couch might be more comfortable, but would probably sit too low. I also doubt I have enough room in this clutterhut room to fit a couch... Suggest you wait until you can quote from a book if you want to impress I rarely quote from books. And I'm not here to impress people. Why would I try to do that when many here obviously know quite a bit more than I do? Or you for that matter... Would be like racing a pack of V8 corvettes with a V6 impala. I've never claimed to be any great guru of antennas. I just fart with this stuff to kill time, and maybe erect a bit better antenna than I would if I buried my head in the sand. I don't have any real "guru" ego to try to protect. I just call em as I see em.. I do have a few books, but I'm almost always too lazy to get up and find one to quote whatever it would be I would want to quote. But my comments still stand. I hear about all these new fangled gaussian designs, but I never hear much about you actually trying or using any of them. If I was trying to design a new type of antenna, I would test it in the real world before trying to convince the masses of the internet if it is a workable design or not. Seems to me it would save a lot of time. From what I read of your posts, I'm not even sure if you know if it's workable or not. To me, that strikes me as a weird way to live. MK |
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On May 3, 8:59 pm, Roy Lewallen wrote:
wrote: Well, it is, as far as designing the antenna. . . MK And MK takes the bait, hook, line, and sinker. The fight is on, and the fish will be played until he can't so much as wiggle a fin. . . Roy Lewallen, W7EL I like to stir it. But there is no fight to be fought. I'm not arguing with him. I just fail to see any real advantage of considering coil current "taper", or whatever you would want to call it when designing a typical bugcatcher. From many of his posts, you would think it's a required consideration, or rewards one with super performance not available to a designer using regular ole lumped coil theory. The coil is still going to end up being mounted in the same place either route you take. MK |
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