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Re: [TowerTalk] "Cables in the woods" or burial

To: Brian Moran <>,
Subject: Re: [TowerTalk] "Cables in the woods" or burial
Date: Mon, 20 Mar 2006 18:22:46 +0000
List-post: <>

     My comments embedded below.

73 de
Gene Smar  AD3F

 -------------- Original message ----------------------
From: Brian Moran <>
> I need some recommendations as to how to run the cables from my tower.... I 
> have 
> fsj4-50b to run, some surplus CATV stuff that's about an inch thick, rotator 
> and 
> antenna control, a cat-5 cable for some antenna switches, and a backup nylon 
> pull cord or two.  
>   I also will be running a 20 amp 120v circuit out there.

As others here have told you and will tell you, keep the electric service out 
of the coax/control cable conduits.  Run a separate conduit or use direct-bury 
(gray jacket) electric cable outside of the conduit.  TO do otherwise violates 
NEC (might not apply to you, though) and is generally unsafe (electric able 
jacket and insulation could tear during installation and eventually contact 
control cables, etc.)

>   The tower is out in the woods; about 250' from the shack. I can go 'direct' 
> with a trench or overland, through woods,  or I can run the cable to a corner 
> of 
> the house and go underneath (crawlspace to garage to shack) (180').  

No question: Go underground the entire length of the run.  Less exposure to 
nature's wrath (lightning, ice, wind, tall four-leged animals with antlers, 
small animals with sharp teeth, etc.)  If you install a large enough conduit 
system (minimum 4 inches, possibly even two of 'em) replacing and adding cable 
will be a snap.  

>   The appealing thing about going in the crawlspace is there is only one 
> buried 
> pipe (septic) to cross (reasonably well known location), while going direct 
> potentially gets into two water supply pipes (exact location unknown).  
> Complete 
> burial is the right thing to do, but I'm unclear on the 
> moisture-sucking-conduit 
> avoidance measures I would have to take, especially here in the pacific NW.

When you install the conduit system, make sure there are a few (two?) low spots 
along the run.  At these spots install PVC T's in the conduit, with the open 
end of the T facing the dirt beneath.  Dig a pit (couple of cubic feet in 
volume) underneath this opening and fill it with gravel a' la Rohn's tower 
bases.  Cover the opening in the T with flower bed cloth (keeps weeds down in 
flower beds) to allow the water to drain but to keep varmints out.  I used 
solid insulated house wire to fasten this cloth in place over the openings in 
my conduit system.  The water that gets in (and it WILL get in) will flow along 
the slope of the conduit to these openings and drain into this gravel-filled 

>   120' of the woods run could be done overland (thereby avoiding trenching) - 
> Has anyone had any experience with conduit held up every 8' with posts? The 
> woods have little human traffic. I would transition to underground once it 
> got 
> near the lawn part of the yard.  
>   Also, having little experience with the air-core hardline stuff (fsj4-50b), 
> what care do I take during the installation, especially on the transition 
> (ells) 
> between conduit and crawlspace? Two separate pieces of hardline, to avoid 
> pulling 1/2 through a bend? 

Don't use an ell (aka elbow) for this transition - the minimum radius you'll 
force the Andrew cable through is too tight.  Instead, use PVC conduit sweeps 
at these points.  These are gentle bends (wasn't he a bear on TV?)  that have a 
larger radius (18 - 24 inches typically) and let you pull stiff cable through a 
ninety with minimal force.  If you can't afford the space for a sweep (they 
stick out 18-24 inches from the house wall, etc.) then consider installing a 
pullbox on your house wall.  You can pull UP to get the coax into this box 
through the conduit system, then pull sideways to get it into the house.  

>   The surplux catv stuff looks like it will survive anything, so I'm not 
> concerned as much about it.
>   Thanks,
>   Brian N9ADG
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