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Re: Topband: Homebrew capacitors

To: topband@contesting.com
Subject: Re: Topband: Homebrew capacitors
From: Richard Karlquist <richard@karlquist.com>
Date: Sun, 29 Sep 2013 19:12:12 -0700
List-post: <topband@contesting.com">mailto:topband@contesting.com>

On 09/29/2013 07:42 PM, Jim GM wrote:
Could have saved more money with a Piece of RF-9913 or RG8 coax cable about
25pF per foot plenty voltage rating.


Only thing can some one please help me on this, do I connect the center conductor on one end of the cable and use the shield on the other end? Or just use the center conductor and shield on one end, while the other end
are floating not used and not tied together?

Neither.  Instead fold the coax and connect to both ends in parallel.
IOW, connect the center conductors in parallel and the shields in parallel. This will greatly reduce the loss due to the resistance of the conductors. Constructing a capacitor out of coax is a suboptimal topology, but folding it
and connecting the ends in parallel at least mitigates the loss.

Rick N6RK
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