----- Original Message -----
From: "Jim Brown" <jim@audiosystemsgroup.com>
To: <amps@contesting.com>
Sent: Monday, July 28, 2008 11:19 AM
Subject: Re: [Amps] Wire
<SNIP>
Further, it has been
> shown (by W8JI, among others) that mismatch is NOT a
> contributor to heating in a choke balun. Heating in a
> current balun is proportional to the square of the common
> mode current. An effective common mode choke (current balun)
> will add a very high resistive impedance in series with that
> common mode circuit, reducing that current to a small value,
> and making dissipation small.
>
> 73,
>
> Jim Brown K9YC
Unfortunately that is not exactly a pratical solution with a balun mounted
in an ATU or at the house end of an open wire feed.
Since the E & I on the open feeders is an unknown at the balun it pays to
use the best materials available. Along with Teflon insulated wire the core
should be wrapped with several turns of Scotch 27 HV tape. Teflon exhibits
cold flow which decreases the voltage rating on the side to the core.
Carl
KM1H
>
>
>
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