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#161
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Tom Donaly wrote:
Kraus was talking about distribution over _length_. Of course, Kraus is talking about the cos(KX) term where 'X' is _length_ and 'K' is the constant that converts that _length_ into degrees. Given 'K', _length_ and degrees are perfectly correlated. -- 73, Cecil http://www.qsl.net/w5dxp |
#162
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#163
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![]() "Richard Clark" wrote in message ... On 19 May 2006 17:09:50 -0700, wrote: Maybe someone can help us here. Hi Glenn, In the half dozen postings that followed this, did you find anything discussed that helped you? Perhaps orthogonal was the wrong word, transverse concepts? 73's Richard Clark, KB7QHC whatever it is, KEEP IT GOING! just got off the tower after pulling up the lifting rope and caught up while my legs are recovering... boy its chilly up there, had to wear my winter coat and hat and gloves! but there are more showers forecast for this afternoon so i'll need some more fresh reading material! FIGHT! FIGHT! FIGHT! |
#164
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Cecil Moore wrote:
Tom Donaly wrote: Cecil Moore wrote: Seems the easiest measurement of nonlinearity would be the harmonics (if any) generated by the antenna that do not appear in the source signal. Which wouldn't tell you a single thing about the current distribution along the length of the dipole. Yes it would. It would be proof that the current distribution along the length of the dipole is sinusoidal no matter what your illusionary perceptions are telling you. For standing wave antennas, if the source is a pure single frequency sine wave and if no harmonics are generated by the antenna system: 1. The forward wave is sinusoidal. 2. The reflected wave is sinusoidal and coherent with the forward wave. 3. Their superposition results in a sinusoidal standing wave with the same angular velocity. Any non-linearity would introduce harmonics. The purpose of most antennas is to radiate electromagnetic waves. That means there is loss. It also means that the current envelope is affected. That's one of the reasons we use EZNEC. I suppose, Cecil, that if you keep repeating the same old tired line, over and over again, you might find someone who will agree with you. Certainly, no antenna measurement would. 73, Tom Donaly, KA6RUH |
#165
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Tom Donaly wrote:
The purpose of most antennas is to radiate electromagnetic waves. That means there is loss. It also means that the current envelope is affected. That's one of the reasons we use EZNEC. The current envelope is affected but remains a linear system function since it is the result of superposition which itself is a linear system function. I suppose, Cecil, that if you keep repeating the same old tired line, over and over again, you might find someone who will agree with you. Certainly, no antenna measurement would. The current envelope is a linear system function. I am repeating the rules and laws of mathematics. Sounds like you need to review the definition of linear systems. You can do that at: http://www.cns.nyu.edu/~david/linear...r-systems.html In particular, quoting: "Systems that satisfy both homogeneity and additivity are considered to be linear systems. These two rules, taken together, are often referred to as the principle of superposition." In general, antennas are linear systems that satisfy the principle of superposition. If they were non-linear, they would not satisfy the principle of superposition. Two linear system functions, like forward waves and reflected waves, cannot superpose to a non-linear function. Therefore, standing waves are linear, not non-linear, functions. To argue otherwise exhibits a certain degree of ignorance. Until the obvious mathematical misconception is corrected, no rational discussion is possible. To the best of my knowledge, Maxwell's equations are also linear system functions so claims of non-linearity also contradict Maxwell's equations. -- 73, Cecil http://www.qsl.net/w5dxp |
#166
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I suppose, Cecil,
that if you keep repeating the same old tired line, over and over again, you might find someone who will agree with you. ========================================= I agreed with Cecil the first time he said it. But I'm only a foreigner. So whatever I say doesn't carry any weight. Or does it? ---- Reg. |
#167
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Reg Edwards wrote:
I suppose, Cecil, that if you keep repeating the same old tired line, over and over again, you might find someone who will agree with you. I agreed with Cecil the first time he said it. But I'm only a foreigner. So whatever I say doesn't carry any weight. Or does it? I dug out my linear network theory book and would like to present a few quotes and comments: "The real world is inherently non-linear." Lightning hitting an antenna can cause arcing and melted wires. "Although nature is non-linear, linear approximations over defined ranges of validity are valid representations of non-linear phenomena." Amateur radio antennas are usually confined to that limited linear range. "The necessary and sufficient conditions for a linear system a (1) validity of the principle of superposition; (2) preservation of scale factor. Does doubling the power input to the antenna ~double the radiated power? Does it ~double the non-radiated losses? "Fortunately for the engineer, however, linear systems are frequently excellent approximations to reality and have a wide range of validity in the real world." Maxwell's equations in particular. Textbook equations for traveling waves and standing waves assume linearity. -- 73, Cecil http://www.qsl.net/w5dxp |
#168
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Reg Edwards wrote:
I suppose, Cecil, that if you keep repeating the same old tired line, over and over again, you might find someone who will agree with you. ========================================= I agreed with Cecil the first time he said it. But I'm only a foreigner. So whatever I say doesn't carry any weight. Or does it? ---- Reg. You're the master of simple approximation, Reg. Cecil thinks your simplified ideas are received wisdom. Knowing you, I find it hard to believe you'd ever agree with anyone. 73, Tom Donaly, KA6RUH |
#169
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On Sat, 20 May 2006 12:14:29 -0000, "Dave" wrote:
KEEP IT GOING! Dave, your trolling effort is rather a poor substitute for the sense of accomplishment. Too many do it far better, with more flair, and offer more entertainment than this pallid use of the CAPS KEYS. |
#170
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Tom Donaly wrote:
Knowing you, I find it hard to believe you'd ever agree with anyone. Reg and I are in perfect agreement on the benefits of a good Cabernet. -- 73, Cecil http://www.qsl.net/w5dxp |
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