Richard,

I may well be barking up the wrong tree, but I seem to remember that current baluns can only be in the ratio 1:N^2, where N is the number of wires making up the transmission line. Hence, because 2 is not a perfect square it will not be possible to make a current balun with ratio 1: 2.

If I'm right, then that would explain why baluns are only made as 1;1, 1:4, 1: 9 etc.

The name Guanella comes to mind as the person who "invented" the current balun, but again I cant be sure.

cheers

Tim R