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Re: [TowerTalk] 43' vertical mod for true resonance on 80M

To: "Mark Robinson" <markrob@mindspring.com>
Subject: Re: [TowerTalk] 43' vertical mod for true resonance on 80M
From: "Rick Karlquist" <richard@karlquist.com>
Reply-to: richard@karlquist.com
Date: Tue, 17 Feb 2009 18:25:52 -0800 (PST)
List-post: <towertalk@contesting.com">mailto:towertalk@contesting.com>
Mark Robinson wrote:
> So maybe a polyester film capacitor? I imagine that the current is major
> issue in the selection of the capacitor here
>
> Mark N1UK

The only low loss RF plastic dielectrics are teflon, polyethylene,
and polystrene.  Capacitors made from polyester/mylar, polypropylene,
or polycarbonate with have something like 2% dissipation factor.  IOW,
the Q will be only about 50.  Also, they may have substantial inductance,
being rolled up.  Not recommended.

Rick N6RK

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