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Re: Topband: matching elevated vertical

To: <topband@contesting.com>
Subject: Re: Topband: matching elevated vertical
From: "Steve Flood" <flood@ixi.net>
Date: Fri, 10 Dec 2004 12:44:34 -0700
List-post: <mailto:topband@contesting.com>

From: "Bob Tellefsen" <n6wg@comcast.net>



You didn't say what power level you want to run.
Assuming it isn't too much, you could wind a simple
matching toroid transformer.
You need a turns ratio of "sqr rt (75/50)" which is 1.22.
This can be worked out as 10 turns to the 50 ohm side
and 12 turns to the 75 ohm side.  Then any minor swr
remaining can be adjusted out at the rig.

If you expect to run over 100 watts, you will need one of
larger ferrite cores, perhaps 2" diameter.

Thanks Bob - I'm only running 100 watts.
So this is a just a 1.5:1 balun then? and I can dispense with the idea of a coil and cap at the feepoint? Sounds good to me - I like to keep it simple. Sevick's book even has a couple designs.



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