[TowerTalk] PL-259 Electrical Joint Compound

[Jim Brown]

On 12/4/2023 5:47 PM, john at 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