"Jim Lux" wrote in message
...
RG-213 and RG-8 (both of which standards are actually obsolete, so you're
buying RG-213 "type" cables) are basically the same.. roughly 0.4" in
diameter, solid polyethylene dielectric, AWG13 inner conductor.

RG-8X is a smaller diameter foam dielectric cable which will have higher
loss (because the conductors are physically smaller, so IR losses are
higher).

Then of the three I mentioned, the RG-8/U would be best?

There are tons and tons of other cables that may be better or worse for
your application.

Are you looking for something for VHF and up? In that case, the foam
dielectrics tend to be lower loss than the solid dielectric. foam
dielectric 75 ohm coax (as used in cable TV systems) is pretty good from a
loss standpoint at VHF and UHF, although you need to check the exact type
(there are some pretty bad 75 ohm coaxes out there, too).

Yes, I am mostly interested in 2m, 1.25m, amd 70cm at the moment. Most
cables I've seen - in my admittedly brief exposure - have been 50 ohm.
Wouldn't 75 ohm cause more loss?

Do you care about exposure to the elements?

Yes, as it will be running from a roof antenna to the house. It is on the
north side of the building though, so the majority of it would not be
exposed to the sun.

Does it need to be flexible?

Somewhat. Once in place it won't be moved around much, if at all.

Are you transmitting through it (e.g. is power handling important?)

I hope to be ;-) I'm taking the Technician Class test Saturday! As for power
handling, all I have at the moment is a 5 watt max handheld. I am interested
in building a 50-100 watt power amp for it, though. You wouldn't happen to
know where I could find a schematic for such an animal, would you? Thanks so
much for your reply Jim!