[TowerTalk] Bundling of tower coax and control lines

[Roger (K8RI) on TT]

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 at ivanshapiro.com
>
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