On Thu, 16 Nov 2006 05:24:14 -0800, Roy Lewallen
wrote:

Hm, I'll have to think about that one a bit. I checked out the Elecraft
info and it appears that the balun is wound on a single binocular core,
not two separate cores. You could make a 4:1 current balun that way if
you could manage to keep the flux from one pair of windings from
coupling to the other, but I don't know right off how you'd do it. I
suspect that some sort of complex winding scheme might make it work. But
if the one you're trying to measure really has two separate cores, I
suspect that measuring the Elecraft might not be a good test of the method.

Roy Lewallen, W7EL

Don't know. However, the folks at Elecraft have a good reputation for
excellent designs so I banked on that.

Going back the original balun I used (which uses separate cores), you
where concerned about tying the leads together for measurements. I,
for the sake of me, can't see why this would be wrong. After all, we
are talking common mode impedance here and the unit did show excellent
choking impedance at its resonate frequency (about 1.58MHz.). But had
a very narrow range. (dropping from over 6K @ 1.58 MHz. to less than
1K @ 3.5 MHz., 700-ohms @ 7 MHz, less than 300-ohms @ 14 MHZ and the
lowest was 130-ohms @ 30 MHz.

To me, that seemed to be lousy performance for a balun advertized
range of 1-30 MHZ.

Danny, K6MHE