On 11/17/2013 6:47 PM, WK1W Ivan Shapiro wrote:
To all who responded:
In several years I'll report on whether or not my split look surrounding
four LMR400UFs, Siamese white cable (RG59 + 18-s) and cat5-e has survived
both the sunny Northern summers and the cold Northern winters.
After cabling with UF a more experienced ham told me about UF deterioration
in sunlight. He tells me Davis' BURYFLEX is the way to go. Thoughts on
this?
Agreed. Even Times Wire has listed a reduced life for their UF
versions. I had 5 runs of it that served as rotaor loops and pigtails
to the antennas. Several had worn completely through with the shield
showing where they lay on the top tower plate. I had one run that was
protected, so when I took them down I decided to use that 28' to make
jumpers. When I cut the second length, I noticed the shield didn't look
right. When I peeled the jacket back, much of the foil and braid had
disintegrated. The Jacket looked OK other than the surface being dull.
It was porous! Probably from UV as the ends were still good (protected
with heat shrink), so the moisture did not come from there.
Remember, in just 6 years at only 730 feet above sea level, mine became
porous so I'd expect them to need replacing more often than that.
The UF versions have a rubber like jacket that is not UV resistant. It
is soft, easily abraded, and difficult to strip with ordinary strippers.
Strips really easy with the old knife or box cutter approach. The
Jacket does not stick to the braid either,
BTW This was after Just 6 Years at a 100 feet in Michigan with the base
of the tower at 630 feet MSL. It's noticeably more flexible than
BuryFlex(TM) which I purchase on 500' spools. BuryFlex(TM)is rugged,
the jacket is TOUGH, flexible, UV resistant, and it's slippery making it
a good choice for crank-ups and rotator loops.
I had purchased another 600 feet of LMR-600UF before discovering this
problem. I've been using up the UF in conduit where I don't need the
flexibility, but it's protected. The new (to me) LM470 crank up is
getting BuryFlex(TM). UF versions would work fine on crank up if you
plan on replacing the coax every few years. That and it catches easily
instead of sliding.
Remember that UV exposure goes up around 10 to 12% per 1000 feet and
that is compounded! IE You add 10% for the first 1000 feet, then add
10% of that exposure. It's not just a simple 10, 20, 30% of the sea
level exposure, so the exposure doubles around 7000 feet. The rule of
72 works just fine. Divide 72 by the % to find out how often the figure
doubles. Normally used on interest earning accounts to figure out how
often the amount will double..
73
Roger (K8RI)
73
Ivan
WK1W
WK1W@ivanshapiro.com
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