John wrote:
Having re-entered ham radio after a 30 year hiatus, I would like to ask
about RG/8U versus other cable types for use in a simple dipole or G5RV
installation with 100W max. transmitter output. In the "good old days"
Low loss "8U" was sort of the standard. There are some newer cable
designations now.

Is there a better "standard" cable for the above use than RG/8U
(specifically Belden 9913 low loss)?

John
AB8O

Hi John,

Some useful information and history is he
http://en.wikipedia.org/wiki/Coaxial_cable. For a given type, you'll find
quality all over the map, from decent to downright crummy. That said, I
recommend a looking at a prospective manufacturer's datasheet before buying.
If there are no specifications available, keep looking!

When it comes to loss/length (for a given cable type), foamed polyethylene
dielectric will be better. Percentage of shielding is probably the next
determining factor. An aluminum foil shield of course will be 100%, but
won't take much flexing before fracturing. Save it for long runs that are
secured in place, and use braided copper or braided copper + foil for other
uses. You'll find most all manufacturers make cables with as much as 97%
braided copper shielding. The last item of concern will be the outer
jacket. PVC is the most common. Some are "non contaminating" or "UV
resistant" types that degrade much slower in sunlight. Use a UV-resistant
type for outdoor applications.

Belden 9913 has a "Semi-Solid Polyethylene" dielectric and can't handle
tight-radius bend. It also has a solid center conductor, which doesn't like
repeated flexing. The shield is "100% coverage Duobond tape" (foil), which
also doesn't like repeated flexing.

RG-58 types are rated to 250W (under matched conditions) safely. If you
plan on running higher power and/or longer runs and/or high standing waves
on the feedline, you should consider something larger. Many hams have used
RG-8X (also called "mini RG-8") with good success. If you're
cost-conscious, this might be a good choice.

Ralph mentioned LMR400 as having a copper coated aluminum center conductor.
It's made by Times Microwave Systems (http://www.timesmicrowave.com/) and is
a solid conductor. Their Ultraflex version (LMR400UF) has a stranded bare
copper inner conductor. He also mentioned Davis RF
(http://www.davisrf.com/) having Buryflex available. As far as I can see,
it's LMR400UF with a different brand name on it. By the way, I've dealt
with them once... very good folks.

Vy 73,
Bryan WA7PRC