On Sat, 29 Jul 2006 23:40:55 -0400, "Tom Coates"
wrote:

I'm seeking a 4:1 balun design that could handle 10 watts efficiently on
20M and would be easy to reproduce without purchasing special ferrite cores,
etc.

There's an old design that puts an electrical half wave of coax between the
two connectors on the balanced side.

What drawbacks does this old design have compared with more modern ones?
Suggestions would be appreciated.

You asked for a balun for one band.

Your proposed solution works fine. It is a narrowband solution, which
is fine if you only want to work 20m.

Very widely used on VHF Yagis which are narrowband applications.

Some have written that the loss in feed to one side of the balanced
load (~0.2dB for RG213 at 20m) causes significant pattern distortion.
However, most baluns are not perfectly balanced.

Owen
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