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Re: [TowerTalk] Crappy LMR600

To: towertalk@contesting.com
Subject: Re: [TowerTalk] Crappy LMR600
From: "Roger (K8RI) on TT" <K8RI-on-TowerTalk@tm.net>
Date: Sat, 26 Aug 2017 02:55:34 -0400
List-post: <mailto:towertalk@contesting.com>
Coax in water? My back yard! Normally, from the spring thaw until early to mid summer (varies) the water table is at, or just below the surface so the BuryFlex to the AV640 is laying in water for 3 to 4 months ea year. (Makes spring mowing a real PITA). By Mid August the water table is 5' down. This year I went to BuryFlex. None of the runs are long enough to justify the larger coax for HF. 75' rig to tower, 100' to pigtails at the top of the tower. The array used 28' pigtails including rotator loops. Now it's just short links. Regular LMR600 works fine 160 - 10.

The only maintenance requiring trips up the tower was the 9913, broken antennas due to Cormorants roosting on the antennas, and water getting into the rotator bearings.

The only lightning damage was pre LMR cables (with one exception). Belden 9913 was like a water hose after a direct hit removed all the weatherproofing and silver plating from the connectors. It matters not what you use for coax. Nothing gives 100% protection from direct strikes. The installation here has taken 17 visually verified direct strikes (according to neighbors) with no damage.

The exception was my fault for taking a short cut because the 144/440 antenna was side mounted at 50'. I only had the jacket grounded at the junction box at the base of the tower. A nearby strike took out the PS fuse to the 144/440 rig.

This area is WET! Basements here require weep tile and a sump. My sump pump failed early this summer and within 12 hours we had a foot of water in the basement. Cost 5 grand, took a week to get it cleaned up and dried out (About half the basement is finished and carpeted.) This past winter there was enough snow cover that there was at most, one inch of frost. Much of the time there was none. Both conditions leave the coax in water. Most of the hams around here don't even bother with conduit, DB, or even BuryFlex. They just stick plain old RG-8 of all types in the ground and I've heard no complaints.

73, Roger (K8RI)

On 8/25/2017 Friday 7:59 AM, Clay Autery wrote:
"That's why they make vanilla and chocolate."  -- Pearl Autery

I'll pay the extra $10 per 100 feet for -DB.  Not just talking about
buried cable.  Also, see my earlier/related comments on subterranean
conduit. Apparently, you've never run a sub-t cable run in a place where
the water table is inches below the surface.

Peace of mind is not overkill.  Neither is avoided trips up towers,
re-trenching, re-pulling, etc. <smile>

______________________
Clay Autery, KY5G
MONTAC Enterprises
(318) 518-1389

On 8/25/2017 1:18 AM, Roger (K8RI) on TT wrote:
Yes, overkill.  If your installation has water problems, then by all
means use the DB versions, but I've not heard of many who do.  With
LMR 400 and 600, I have never had water ingress and no maintenance
issues..  The only coax that has required maintenance was The UF
versions of the LMR cables and Belden 9913 that works like a hose. I
never had problems with pre 9913 Belden cables.
My yard doesn't have problems with stones in the dirt, so I use
buryflex which has a tough jacket but no gel fill. Otherwise I'd use
DB cables if I had stones in the dirt.  Main cables from rigs to
towers here are run in conduit.

Wet cable? Again, The only cables I've had a problem with were 9913
and the UF versions of the LMR cables. I've had some of those cables
in use for over 20 years.

73, Roger (K8RI)
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73

Roger (K8RI)


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