Well, 50 feet of RG-58 has about 3/4 dB loss at 14 MHz. And when it's
old. . . I've got RG-58 that's well over 20 years old, and can't measure
the difference in loss between it and new cable. If it's damaged, it
might create an impedance bump, which you might or might not notice. But
that's true of larger diameter cable, too.

I'm bemused to find that today's hams have somehow gotten convinced they
all need BIG cable for a BIG signal. Maybe they've been listening to the
same ads that sell people on monster audio cables and SUVs. But I sure
hate to see this misleading concept being passed along to newcomers.
They'll fall for the ads soon enough without help.

Roy Lewallen, W7EL

Mark Keith wrote:
Roy Lewallen wrote in message ...

Mark Keith wrote:

. . .
Also, I suspect excess loss if the noise and signals drop compared to
any other antenna. If the coax is not bad, old or waterlogged, or thin
stuff like rg-58, then I'd suspect excess loss in the autotuner. . . .

Out of curiosity, just how much loss do you think "thin stuff like
RG-58", say 50 feet of it, has on 20 meters?

Roy Lewallen, W7EL


Normally it shouldn't be too much. But if the "thin" stuff is old, or
has been damaged , it might be more than usual. MK

Roy Lewallen wrote in message ...
Well, 50 feet of RG-58 has about 3/4 dB loss at 14 MHz. And when it's
old. . . I've got RG-58 that's well over 20 years old, and can't measure
the difference in loss between it and new cable. If it's damaged, it
might create an impedance bump, which you might or might not notice. But
that's true of larger diameter cable, too.

I'm bemused to find that today's hams have somehow gotten convinced they
all need BIG cable for a BIG signal. Maybe they've been listening to the
same ads that sell people on monster audio cables and SUVs. But I sure
hate to see this misleading concept being passed along to newcomers.
They'll fall for the ads soon enough without help.

Roy Lewallen, W7EL

I don't think I've really promoted the cause of excess loss in thin
coax, but it is worse than thick cable. By damaged, I mean waterlogged
generally. There are not too many other ways to damage it to make it
overly lossy. I've seen some old thin coax that was pretty bad as far
as loss. Quite noticable on 10m anyway...Maybe not 20m as much. I do
prefer larger coax any day of the week, but thats mainly to reduce the
losses when I have a fairly large mismatch. IE: warc band use with
tuner, etc. Also less loss on higher freq's. In this case, I only
mentioned it in case the tuner ends up not being the problem. The coax
needs to at least be considered. But I think the tuner is the likely
culprit. MK