*Article by Charles Greene, W1CG*

My 4:1 current-type balun is wound on a FT-114-43 core. The FT-140-43 is a little easier to

work with, and maybe the FT-140-77 would cover 160-10. This one is reasonably flat from 4.5

to 35 MHz but drops off a little at 3.5, 40-ohms with a 200 ohm resistor on the high side instead

of the 50-ohms I get on the higher bands.

The reason I used the R/S speaker wire is that last summer Wayne (N6KR) reported his

double Zepp with a R/S speaker wire feed line, and someone at ARRL lab measured the

impedance and came up with around 120 ohms. You are supposed to use something that has

an impedance of approximately 2X the input impedance, and this was close.

Now, to the construction instructions:

Refer to the schematic (or figure 2-1A on page 18 of Jerry Sevick’s book “Building and Using

Baluns and Ununs”).