>Rich says:
>
>>The solution is semi-obvious: put the balun where SWR is minimal, and use
a
>>balanced tuner circuit.
>
>Come off it, Rich, it's not semi obvious. It's
>standing-there-shouting-glaring-one-in-the-face obvious!
>
/\ guffaw
>Even with ferrite baluns, it works - and extremely well, too.
/\ Extremely well is hardly the case with large suds. I built an
"Ultimate Transmatch" with the requisite ferrite balun in the output.
40m and 80m worked ok with 1500w. On 15m, the grounded case of the tuner
was unpleasantly hot with RF. With my o'scope, I could see that the
output was a distorted sinewave on 15m. I also saw that the output was
not balanced by c. 40%. 10m was worse. I talked to some friends in
Newington and they were abundantly aware of the ultimate problems with
the "Ultimate Transmatch" and they were looking for something better to
publish in *QST*. The result was the publication of the article on the
balanced tuner in February, 1990
>The technique has
>been around a long, long time - I first saw it over 40 years ago, but I
>suspect the idea of making a balanced tuner puts people off. Not that it's
that
>difficult, as Rich has demonstrated.
>
later, Peter
- R. L. Measures, 805.386.3734, www.vcnet.com/measures.
end
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