On Oct 25, 9:16*pm, tom wrote:


He's right, Cecil. *It's probably becoming an issue by 432, and I'd
really have to question anyone using it above 1296.

tom
K0TAR

At 432 mhz, I had better luck with the 300 ohm TV line,
than I did using mediocre CATV cable and a balun.
This was feeding a UHF TV antenna that I used for ATV
on 70 cm. The 300 ohm line had the lower loss of the two.
Until it rained.. Then it was blackout time until it dried.
I have 300 ohm line feeding a 40 m dipole strung up in
the attic. It's an emergency antenna, and I use the 300
ohm line and a tuner to work any band 40-10m.
Being as it never gets wet, it works out pretty well.
300 ohm TV line is usually pretty good. Until it gets wet.
In the real world, I generally prefer coax. On the HF bands
it's about all I use. But the 70 cm ATV antenna was one
case where it paid to use the TV line vs coax. Or at
least the coax I had on hand.. Which was Beldon duo-shield
RG-6 type 75 ohm CATV cable.
Going by a gut hunch, I'd say the twin lead is probably
better than mediocre coax on 1296 mhz. You would need
some fairly high quality coax to equal the loss performance
of even cheap 300 ohm line on 1296 mhz. Or I would think
anyway, judging by it's use on 70 cm. I would think the
advantage would become more lopsided towards the 300 ohm
line, the higher in frequency you go.
I could look up the appx numbers in a book, but I'm too
lazy to get up out of my chair. :/