In message , Bill M
writes
alchazz wrote:
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

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


Have you tried the 50 ohm cable directly (with a 4:1 xfmr at the
dipole) to see how it works? The 300 ohms for the dipole, etc only
apply at one single frequency and with signals that strong there really
shouldn't be an issue with additional loss. Reflections will not show
up visibly with digital tv.

Part of the issue here is winding the balun and set transformer at UHF
frequencies. Not impossible to do with inexpensive parts (multicore
ferrites) but I wonder if its really necessary?

GL,

Yes, just go ahead and use a normal 4:1 off-the-shelf TV/FM balun. They
are only a couple of dollars. The effects of the incorrect impedance
transformation will be negligible, and there's little to be gained by
trying for 'perfection'. If it doesn't work, you've lost virtually
nothing. [Note that, if it doesn't work, it won't be because the ratio
is wrong, or that the coax isn't 75 ohms.
--
Ian