Hi Marshall,
At 12:03 AM 3/28/97 +0000, you wrote:
>The expression "balanced tuners" is kind of intriguing. I presume
>you mean tuners that offer connection for balanced feedline. They do
>that by including a balun, and there is no practical difference
>between having the balun inside the tuner box or outside it.
You are correct that many of todays tuners use a balun to achieve the
balanced state. But 50 or more years ago, there were a lot of truly
Balanced tuners in use. They were balanced in the sense that each side of
the ladder line saw exactly the same circuit.
This was achieved by using a link coupling to the antenna, and by a shunt
inductor which was tapped at both ends. Thus the tap on each side could be
moved, maintaining the balance.
Some tuners using this or similar techiques are still around. Chapter 25 of
the ARRL Antenna Book illustrates several balanced tuning arrangements. The
Johnson Matchboxes are examples that are still in common use.
It is true that these "Transmatches" are in effect baluns. IMHO, however,
some of these circuits are much more efficient than using a separate balun
to force balance into an inherently unbalanced circuit.
CUL,
Bob Kellogg, AE4IC, Greensboro, NC
Prolably, but not nececelery. - Benny Hill
WIMPS: Qs=000 30m=0 17m=0 12m=0 States=00/00/00
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