Tom W3TDH skrev 2012-11-25 23:08:
Thanks to the generosity of a fellow radio club member I now have the
use of a Yaesu FT-1000 (no Suffix). Since it has a built in antenna
tuner, that I'm hoping to use, I need to ask what the best way is to
couple the window line that feeds my folded dipole antenna into a
short; say twenty feet; coaxial feeder from the radio. I used an Icom
AH4 antenna coupler with my FT-857D on this antenna with very good
results. I would guess that I need a balun but which type is a
mystery to me.

So is a balun a good solution to this challenge or should I resort to
the two pieces of coax in parallel that I have read of elsewhere?
When you use the two parallel coax leads do you ground and/or bond the
two shields at the transceiver end? Further since the FT-1000 does
not have obvious balanced feed line terminals would I connect a
balanced feed line to the ground terminal and the the center pin of
the SO239 connector by using say a banana plug.

Since I really am asking questions I hope there is already a consensus
answer as I would not be able to sort out the various sides of any
debate. Thank you in advance to all who choose to tackle this
question.

Tom Horne W3TDH


A 4:1 current balun, A.K.A as a 4:1 Guanella balun, does a god job.
Constructions using just 2 coax-lines will have problems to cover all HF
bands. To little inductance at the lower bands and you have to keep the
length less than a quater wave on the higher ones.

Google on 4:1 guanella balun and you will find a lot of sites that shows
how to make one. Just be aware of those who just uses one core, these
designs will degrade the performance (common mode) of the balun.

73 and Good Luck
Ben / SM0KBW