Topband: matching elevated vertical

Steve Flood flood at ixi.net
Fri Dec 10 14:44:34 EST 2004


From: "Bob Tellefsen" <n6wg at 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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