Ian White GM3SEK wrote:
Roy Lewallen wrote:
wrote:
. . .
Will a 4:1 current balun transform a random impedance Z1 to Z2 where
|Z2|=|Z1|/4? I know Roy pointed out that this won't work for a voltage
balun...
No, it won't either. The amount of error with any balun type depends
on the balun construction. You'll just have to build one and see what
it does.
It would be interesting to know what your antenna Z looks like on each
band at the input to the existing balun. That is, what do you get when
you connect your antenna to the balun output and the analyzer to the
balun input?
Since the balun is connected to a tuner, inaccurate impedance
transformation won't matter much. The only concern would be if it's a
sign of some other problem in the balun.
Well, yes and no. Good tuner designers go to a lot of trouble to
maximize the Q of the inductors to minimize loss. It's doubtful that the
Q of the balun inductance is nearly as good, so loss is liable to be
higher if the balun is contributing a significant amount of reactance.
Otherwise, I agree, it doesn't make much difference. The balun might
move the impedance to a point where the tuner can't match it, but it's
just as likely that it'll move an otherwise unmatchable impedance to
within the tuner's range.
Roy Lewallen, W7EL