On Wed, 28 Sep 2011 23:26:24 -0700, "Sal" wrote:

"Jeff Liebermann" wrote in message
.. .

... am now a practicing member of the Cult of
75 ohms. The difference is subtle. While worship of the 50 ohm idol
results in the maximum power transfer, the change to 75 ohms results
in minimum coax loss and somewhat easier antenna design. However, the
major benefit is it allows one to minimize the tithe paid to vendors
as CATV coax is cheap and readily available. I suggest you consider a
religious conversion.

Yes. Somebody in this group (you, maybe) previously promoted 75 ohm cable.
This past spring, I was modeling my 20m Field Day dipole, varying size and
height for best pattern shape and minimum VSWR. At optimum, it had almost
exactly 75 ohm feedpoint impedance. Having plenty of TV coax, I didn't
hesitate to go with it. The antenna worked wonderfully well at FD.
Transmitter seemed to like it just fine.

Probably me. I tend to promote the use of 75 ohm coax and systems.
Most of the coax cables to my rooftop antenna farm are 75 ohms. The
justification was convenience and price. I obtained five 1000ft rolls
of RG6a/u mutations (some with messenger wire), and some used hard
line, and couldn't resist using it. The only problems seem to be
getting accurate readings on my test equipment and having enough
F-to-N or F-to-BNC adapters.
http://www.qsl.net/n9zia/wireless/75_ohm_hardline.html

Note that using 75 ohm coax on a VHF/UHF repeater is a really bad
idea. Duplexers, isolators, circulators, cavities, and such are very
sensitive to mismatch. For repeaters, use only 50 ohms.

--
Jeff Liebermann
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558