[TowerTalk] Coax choice for crank-up - looking for TT experience/recommendations

Roger (K8RI) on TT K8RI-on-TowerTalk at tm.net
Tue Jul 11 01:32:36 EDT 2017

I had somewhere between 1500 and 2000 feet of 9913 on a guyed 45G.  I 
believed that a good weatherproofing would do the trick, that is until 
lightning struck the top of the tower. It not only removed ALL of the 
weatherproofing, but the silver plating as well, leaving the connectors 
looking like sandblasted brass.  Less than 15 minutes later I had water 
running out of the 144/440 rig and on to the desktop.

I replaced all of the 9913 with LMR400 and eventually went to LMR600 for 
VHF and UHF.  With only two exceptions, that was the only time I had 
water in the coax. One other time was also with 9913.  The wind blew the 
coax against the end of the shop roof. The edges of those shingles made 
quick work of the jacket, shield, and dielectric.  The other time was 
from using LMR 400UF outdoors as rotator loops. The jacket is a rubber 
like substance, that is easily abraded and quickly becomes porous. Four 
of the 5 pigtails had braid showing where the jacket had worn off 
completely from just laying on the flat top plate of the 45G. UF is not 
recommended for outdoor use and has a projected life of only 10 years, 
half that of the Non UF versions.

73, Roger (K8RI)

On 7/10/2017 Monday 7:32 PM, Steve Maki wrote:
> Of course any coax that has a spiral shield or spiral dielectric (like 
> traditional 9913), will *really* take on water, fast. A braided shield 
> will wick water surprisingly fast. Corrugated with hollow center 
> conductor will pipe water down to the bottom end and both ends will be 
> corroded.
> Again, they can all be weatherproofed easily.
> -Steve K8LX
> On 7/10/2017 19:06 PM, I wrote:
>> Almost any coax will take "take on" water to some extent if you give 
>> it a chance. The only exception that I've found is smooth wall 
>> hardline, where the closed cell dielectric is *bonded* to both the 
>> smooth shield and the smooth center conductor.
>> Any other style, be it corrugated hardline, braided coax, semi air 
>> line, whatever, will be ruined if you don't weatherproof the 
>> connectorized ends.
>> Apparently there are some folks who don't believe it's possible to 
>> weatherproof connectors. That is a totally false belief.
>> -Steve K8LX
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Roger (K8RI)

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