[Antennas] Capacitor Recommendation Needed

Sat, 4 Oct 2003 16:19:49 -0400

There are capacitors with mica dielectric manufactured specifically for that
purpose and are rated in terms of the number of RF amperes flowing through
them. They are known in the trade as "Transmitting Micas". I would try that
company out in Nebraska, or somewhere like that, that sells transmitting
grade components.

Bob Lay (W9DMK) in Dahlgren, VA
http://www.qsl.net/w9dmk
----- Original Message -----
From: "Dennis Ashworth" <[email protected]>
To: <[email protected]>
Sent: Saturday, October 04, 2003 2:07 PM
Subject: [Antennas] Capacitor Recommendation Needed

> I need to insert a 1000pf of capacitance in series with my 80M vertical to
> move the resonant frequency up to the phone band. I have been using a
> vacuum variable, but would like to use it in another project - and change
> to a fixed capacitor. The logical choice would be a fixed 1000 pf vacuum
> capacitor. Failing to locate a vacuum cap, what low loss dielectric
> materials should I be considering given the frequency, voltage and current
> involved. The driving impedance is 40 ohms and I run the legal limit.
> Therefore, currents will be in the 6-8A range ... voltages probably less
> than 500 V.
>
> Thoughts on dielectric materials and sources would be most appreciated.
>
> Dennis, K7FL
>
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