I built a 4:1 balun based on an old QST article.
http://www2.arrl.org/members-only/ti...df/9008028.pdf

I used 10 Fair-Rite 2643540002 beads on each of the 2 pieces of
RG-71B/U 93 ohm coax. These are #43 ferrite .562 OD .250 ID and 1.125
inches long.

Is this enough #43 ferrite to be an effective balun on 80 thru 10
meters?

The balanced side is connected to about 30 ft of 450 Ohm window line
that feeds a 135 ft off center fed dipole at 75 ft from one end. The
unbalanced side is connect to the coax output of an AEA ET-1 manual
tuner through 20 ft of Mini 8 coax.

Will this type balun work with the high swr that it will see on some
bands?

I can get a good match on 80 thru 10 meters except for 12 meters. It
seems to work, but I may be converting more RF to heat than radiating.
The external balun is a matter of convenience as it is a lot easier to
bring the coax into the tuner than it is to bring in the window line.
Would it be better to just use a 1:1 balun between the coax and the
window line?

Mike kc9doa