Tam/WB2TT wrote:
"Boozo" wrote in message
ups.com...
Have a 100 foot roll(approx) of used coax cable which has no markings
printed on it.
Can anyone tell me how I can work out what it might be ? e.g. 75 ohm or
50 ohm or ?
Going by the size it looks similar to 50 ohm but I'm not sure.

Any suggestions would be appreciated.


If it has a solid center conductor, it is almost certainly 75 Ohm. The only
exception I can think of is some weird version of RG58.

Tam

I do have a bunch of older RG-58 with solid center conductor, and
pretty much all the HP BNC patch cables I've seen the insides of have a
solid center. I believe the various semi-official versions (RG-58/U,
RG-58A/U, RG-58B/U and RG-58C/U) tell whether the center is supposed to
be solid or stranded, but that seems to have become *******ized. A
quick Google search for RG58A yields cables with both solid and
stranded centers. How about Belden 9913? Of course, the construction
of that line is "different" enough that it would be hard to mistake it
for something else, and I assume the poster would have mentioned the
strange construction. Also, you're likely to find a solid center in
higher impedance line like RG62/U, and you're likely to find stranded
center on 75 ohm line (like RG-11/U, and others). And of course for
some surplus custom line, all bets are off about both stranding and
impedance!

Cheers,
Tom