[Antennas] Old Coax
Cletus W Whitaker
[email protected]
2002年9月12日 17:32:51 -0400
de WB2CPN South Central Pennsylvania 2002年09月12日
It's best to generalize about coax aging. The specifics will depend more
upon the maker and the quality of the materials that are used. Some of
the worse cases I've encountered since 1946 revolve around the oxidation
of the braid, and chemical reaction between the braid and the plastic
jacket. On occasion I've seen where the center conductor had reacted
with the dielectric material. I've found that high quality coax, using
a well tinned or silvered braid, will last for years and years. On the
other hand, some military RG-13 I installed in 1954 got full of water and
didn't last two years. One common fault with coax is that if a sharp
bend is made, the center conductor will migrate toward the braid. A hidden
fault with running high power is SWR current peaks keep wearing away at
one spot. Same thing for voltage peaks. The bottom line: If your
coax tests good, then use it, but always keep an Ace in the Hole.
73 Clete