Roy,

Take a look at http://home.earthlink.net/~christras...k4to1Balun.pdf
for a supposed 4:1 current balun on a single hole torroid. I have no
first hand experience with this design.

73,
Larry, W0QE



Roy Lewallen wrote:


I don't know of any way to make a 4:1 current balun with a single
one-hole core. I think it's possible with a two-hole (binocular) core if
done right.