Ultraviolet from the sun is what degrades PVC I believe... ?
And yes Steve, I have observed the same thing with PVC vs Polyethylene.
73, Jim W7RY
On 2/14/2023 6:25 PM, Steve Jones wrote:
Art,
I have gone to Davis Bury Flex for outdoor use. The jacket is polyethylene
instead of PVC. I have lots of polyethylene water pipes that have stood up
to 40 years of hot sun and cold freezes. My rigid PVC water pipes all need
to be inside a heated pump house or they get brittle and crack!
73,
Steve
N6SJ
-----Original Message-----
From: TowerTalk <towertalk-bounces@contesting.com> On Behalf Of Art
Greenberg
Sent: Tuesday, February 14, 2023 12:50 PM
To: TowerTalk@contesting.com
Subject: [TowerTalk] Coax Life Expectancy
I just had to take about 250 feet of "brand X" coax out of service because
the outer jacket is cracking. Three runs up my 50 foot crank-up tower
hanging from a support at the top, and three runs from the top of the tower
through the rotor loop and up to the antennas on the mast. The cable had
been in service for about 2-1/2 years here in north-central Florida (near
Gainesville).
The cracking occurred in places where the cable moved (the rotor loop) and
where it did not (taped to the mast or boom). Where the coax was protected
from the sun in a length of split loom, it didn't crack.
In some places the braid was easily visible behind the cracking. I did
observe water exit the cable when I applied pressure to the cable in a
horizontal run.
I have both "brand X" and "brand Y" cable running in underground conduit
from my entrance panel to the base of the tower. Where the cables exit the
conduit and make the short run to the tower, I can see the cracking in
"brand X" but not in "brand Y". In fact, "brand Y" still looks new. I am
putting off replacing the cables in the conduit. It will need to be done
eventually.
I'm relatively new to this location, having moved from New Jersey 12 years
ago. This is my first experience with coax failing in this manner, and my
first experience with "brand X." Is this to be expected in my location? Is
"brand X" exhibiting expected service life?
Note that "brand X" claims to be suitable for outdoor use.
TIA.
--
Art Greenberg
WA2LLN
art@artg.tv
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Thanks and 73, Jim W7RY
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