"ferrymanr" wrote in message
...

I would guess that you are right Danny and this is a voltage balun. I dug
it out as I have recently moved to a flat in the centre of town 100 yards
from a large telephone exchange and surrounded by noise sources. My old
trusty vertical is giving me so much noise here that I want to put up a
balanced antenna in the hope that this will reduce the interference. To
minimise this noise I need a well balanced system. I already have coax up
to the roof and balanced line would be difficult to route so am planning
to fit a balun either at the dipole centre or a few feet below with a
short balanced feed. I dug this balun out as it looked like it would give
good balance. I have another (current) balun which has a simpler bifilar
winding. I'm not sure which will be best for my application.
Incidentally I only run QRP so efficiency is a major factor. I also
considered a folded dipole using 600 ohm line as that would be less prone
to static noise but would then have to look at a 4:1 design.

73 de Dick G4BBH


Hi Dick,
You might want to try a horizontal loop antenna, they are very quite with
respect to QRM.

http://www.bloomington.in.us/~wh2t/loop.html

If you need a 4:1 balun :
http://www.bloomington.in.us/~wh2t/balun.html

7, Ace - WH2T