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Re: [TowerTalk] 80m dipole with open-sleeve parasitic

To: "" <>
Subject: Re: [TowerTalk] 80m dipole with open-sleeve parasitic
From: "Rick Karlquist" <>
Date: Wed, 19 Jan 2011 14:36:59 -0800
List-post: <">> wrote:
> okay Rick, thanks for the clarification.
> I guess what I'm thinking is that there is no single LC match, even with
> two wires that gives equivalent bandwidth.
> Things that I'm ruling out: switching the LC values for different
> frequencies.
> Spreading the wire ends of the two wires up to 3 feet or more (I think
> that's unwieldy)
> So while what you say sounds right, I don't think there's a pratical,
> single LC value, 80m, antenna that's equal.
> If there is, I'd like to hear the exact dimensions so I can create a NEC
> simulation.
> Again I'm ruling out very wide cage dipoles.

We agree.  We are talking about a fixed lumped element network
connected to a plain wire dipole, no fancy stuff.
Again, I refer you to the QST articles previously cited.

When discussing these designs, loss is relevent because adding
loss, in and of itself, broadens the bandwidth.  If this is
what you want, you can always add loss to any system.

BTW, there is a theoretical broadbanding limit described in a
paper by Fano (see W7ZOI's QST article).  I believe the lumped element
networks approach this limit.  (It's kind of like the Shannon limit.  Fano
givesa limit but doesn't tell you how to get there).

Rick N6RK


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