Stef wrote:
If I were you, I would remove this 4:1 balun and solder the coax
direct to the twinlead. I would then use good coax right to the
radio.

The reason is: the impedance at the solder point is not 300 ohms and
with your balun, you're inserting more losses .

True, but without a balun, one is introducing common mode effects.
I, personally, would use a 1:1 choke at the balanced to unbalanced
connection point.
--
73, Cecil http://www.qsl.net/w5dxp



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The reason is: the impedance at the solder point is not 300 ohms and
with your balun, you're inserting more losses .

True, but without a balun, one is introducing common mode effects.
I, personally, would use a 1:1 choke at the balanced to unbalanced
connection point.

There sure is RFI coming from the coax . I should try it. I'll
disconnect my coax and try 10 turns of coax as a balun. I'll know for
sure. Or would the "bead baluns" be better ?

Stef wrote:
There sure is RFI coming from the coax . I should try it. I'll
disconnect my coax and try 10 turns of coax as a balun. I'll know for
sure. Or would the "bead baluns" be better ?

Bead baluns would be better but cost more. One could virtually
eliminate common-mode currents with $1000 of bead baluns. :-)

A good engineering rule of thumb is to install a balun whenever
the transmission line changes from unbalanced to balanced.
--
73, Cecil http://www.qsl.net/w5dxp



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Cec, do you own shares in Fairite or Amidon? ;o)

All the enquirer needs to do is buy an HF-grade ferrite ring, about 1.5" or
2" in diameter at a car-boot sale, and wind on about 8 distributed turns of
18 or 20 gauge twin, clear-plastic, stranded, speaker wire.

Insert this choke balun at the junction of the coax and the balanced
feedline. If it is outdoors dunk it in some water-repelling goo.

For multi-band working make the coax as short as possible and make the
balanced feedline long enough for the whole to extend from the antenna to
the tuner, with perhaps a little extra.
----
Reg.