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Old May 19th 09, 01:27 AM posted to rec.radio.amateur.homebrew
Ralph Mowery Ralph Mowery is offline
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First recorded activity by RadioBanter: Jul 2006
Posts: 702
Default 6 to 1 balun design


"alchazz" wrote in message
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I am looking for a 6 to 1 balun, 300 ohms balanced to 50 ohms coax. I
don't need one that handles transmitter power as I am only using it for a
receiving antenna.

I have on hand several hundred feet of 50 ohm coax, RG58 modified (IEEE
802.3). I want to use it to connect my 300 ohm TV dipole antenna in my
attic to my HDTV in the basement. And, of course, I would need a 50 ohm
to 75 ohm match at the HDTV.

We only watch over-the-air TV. Why? Because I live within 2 miles of
three 1000 ft TV towers. In fact, the dipole in the basement works quite
well. But I do get dropouts during storms; go figure. I get 17 channels
for free, so why go cable or FIOS. Nothing worthwhile there anyway.

So can someone point me to a good site for balun design. I've done the
Google searches, but all that I find seem to be for high power
applications.

Any help would be appreciated.

Al


I would not worry about the balun for TV reception. Just use the 300 to 70
ohm one. I think you will get a lot of loss with the rg 58 coax. Go to the
rg6 type coax for much lower loss.

I have a 2 meter horizontal M2 antenna up 70 feet and when the cable goes
out I connect it to my converter box. It is fed with about 130 feet of low
loss rg 8 type coax and from there I go to about 25 feet of rg-6 type to get
to the TV. I get about 30 channels with this setup. Probably 30 to 50
miles from most of the transmitters.

It is possible the TV signals are overshooting you. Sometimes almost under
a tower can be worse than being out several more miles. As someone
mentioned you may be getting multible and causing dropouts. I had a 2 meter
antenna in the house hooked on the back of a transceiver and people walking
around the room would sometimes cause a dropout and they were not in a
direct line from the rig to the repeater.