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#1
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The Formula
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. |
#2
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The Formula
Sal M. Onella wrote:
[...] plonk ... JS |
#3
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The Formula
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. |
#4
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The Formula
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. |
#5
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The Formula
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 |
#6
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The Formula
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 |
#7
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The Formula
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 |
#8
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The Formula
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 |
#9
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The Formula
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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