On 12/4/2023 5:47 PM, john@kk9a.com wrote:
LMR400-Ultraflex
cable I installed about 15 years ago has started to decompose. At the time
of installation, I knew the Ultraflex version has a shorter life span but
wasn't expecting such severe decomposition. The jacket is crumbling due to
its rubber composition.
The only LMR cable I've ever owned was an end length of LMR400-UF that I
bought used at that big hamfest that was on the SW side. This was
probably 20 years ago, when I was getting back on the air. It was not
nice cable.
OTOH, about 15 years ago, I helped N6RZ's widow liquidate his station
and massive stash of stuff. I bought the hard line and a lot of the
other stuff, but took the coax, almost all of which was in pretty good
condition, to an NCCC meeting for the guys to take. They all turned
their noses up at it, so I brought it home and made stubs with it, all
of which measured "like new" (meaning a nice high-Q resonance,
indicating very low loss). Only one or two short pieces that had been
stored in a pretty primitive outbuilding showed any significant
deterioration; opening it up showed a badly oxidized copper shield.
My lesson from that it's a waste of money to replace coax just because
it's old. To replace it with something better, sure. :) The only coax
I've had to replace are a couple of lengths that got water in them from
home-brew center insulators that weren't well enough sealed.
73, Jim K9YC
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