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[Antennaware] Model for Trapped tribander with log cellfeed

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Subject: [Antennaware] Model for Trapped tribander with log cellfeed
From: (Pete Smith)
Date: Tue, 04 Jun 2002 13:09:41 -0400
At 06:32 PM 6/2/02 -0400, Guy Olinger, K2AV wrote:
>It is a formidable task for an experienced modeler. Full of
>It's like trying to learn how to hit a baseball starting on major
>league curve balls.

To be a bit more specific, I think the biggest problem is knowing the 
R,L,and C of each trap, as well as accounting for their physical length as 
part of the element.  I don't believe that modeling a classic LP feed is a 
big problem as long as you don't need to know the feedpoint impedance.  I'm 
presuming that you basically want to model the antenna as a guide to 
identifying interaction with other antennas in the vicinity -- if not, then 
back to square 1.

Years ago, I went looking for a model of a TH-7, and N6BV, who knows a 
little about this stuff, shared with me what he used -- three single-band, 
monotaper-element models, which shared the element spacing and feedpoint 
phasing with the real thing, but that was about all.  Those models seemed 
to be quite a fair representation of the TH-7, and perhaps you could do 
something similar with the trapped director of the Cushcraft.  You could 
probably even model individual driven elements placed at approximately the 
right place in the log cell, to avoid that complication.

73, Pete N4ZR

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