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#2
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On Sun, 22 Aug 2004 22:15:56 -0400, "J. McLaughlin"
wrote: I shall file in my list of interesting-things-to-think-about-in-a-serious-way the issue of what happens to the behavior a wave antenna having a "wire" on the ground directly under the antenna wire. I do recall dealing with a similar issue where I was verifying a modeling issue by testing the Zo of a very long wire over a conducting plane. Hi Mac, Where the discussion remains technical, it seems to me that both Tom and Yuri are saying the same thing. On the other hand, they may say it differently, but the conclusions seem to agree. Your experience and studies to this point would be instructive. 73's Richard Clark, KB7QHC |
#3
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KB7QHC:
Where the discussion remains technical, it seems to me that both Tom and Yuri are saying the same thing. On the other hand, they may say it differently, but the conclusions seem to agree. Huh? Which "same thing?" Yuri |
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#5
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![]() KB7QHC: Where the discussion remains technical, it seems to me that both Tom and Yuri are saying the same thing. On the other hand, they may say it differently, but the conclusions seem to agree. Huh? Which "same thing?" Yuri Which difference? 73's Richard Clark, KB7QHC What are you refering to? Can you be more specific? Wire laying on the ground "changing" resistance or terminating Beverage in the ocean? Yuri |
#6
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#7
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![]() Hi Yuri, As Mac said, there are many "its" in the quote. However the vague combinations do not resolve to different interpretations as you persist. The extra wire leads to the same conclusion you BOTH describe and that is Beverage-like antenna characteristics. As that is a unique consequence of ground's retarding the wavefront, it necessarily follows that Tom maintains (and directly states) that the extra wire does NOT interfere with that action. He states why - tight coupling. He no where states that metallic copper assumes ohmic loss as the loss is a consequence of proximity to earth. Further, I've seen no statement from you or Tom that maintains the extra wire destroys the Beverage-like antenna characteristic, hence there is not a hair's width difference between you two. 73's Richard Clark, KB7QHC First of all, I have not done experiments to compare single wire Beverages vs. dual wire, with the other wire being laid underneath the Beverage. I had the problem with statement "the wire below the Beverage is the wire couples to the lossy media below it so well it becomes very lossy" as far as I know wire maintains it's conductivity regardless where it is laid. Perhaps more accurate statement would be that wire laying on the ground becomes less significant in its contribution to the performance of the above Beverage. But because the "ground" wire is connected typically at the termination point and at the feedpoint to the Beverage system, I am not sure that it can be "ignored". Some claim this forms the "open wire" parallel system and has significant effect on the Beverage performance. There is dispute as far signal arrival angles are concerned, some signals get subjected to wave tilt due to poor ground, some signals have their own tilt due to propagation and terrain effects. To find out the reality, the exact systems should be compared in various situations. Modeling might not provide fool proof answers due to some programs having hard time to model reality, that can be confused by varying ground characteristics along the Beverage. Yuri, K3BU |
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