[Towertalk] Burying Coax in Conduit Trench

Howard Klein k2hk@arrl.net
Wed, 28 Aug 2002 17:59:37 +0000


Herb Wrote:
From: Herb Rosenberg <kg6ok@pacbell.net>
Subject: [Towertalk] Burying Coax in Conduit Trench

I am considering running a 30 foot trench from the base of my tower to my 
ham shack for my coaxial cables, and would like to here comments /
suggestions from anyone that has done this before, on things to do / not do, 
etc.
All of my cables are 9913, and I have a bundle of about 8 feed lines.
I am thinking about a 4 (four) inch conduit pipe, and wondering about a few 
things:  (BTW,I live in Southern California)
How deep should the trench be below ground?
What kind of pipe is best to use?
Should I drill holes in the bottom side of the pipe so water can drain out?
Should I place some gravel on the top of the trench before I lay the pipe on 
top, and cover it, to help with drainage?

Herb - KG6OK

K2HK Wrote:

Herb,
I do not pretend to be an expert in this but I have just finished burying my 
second conduit. My first has been in the ground for several years. First I 
would recommend rather than a single 4 inch pipe I would use two 2 inch or 3 
inch pipes. My reasoning is the wires tend to tangle when there are too many 
in a single pipe making it difficult to pull new cables even if there is 
space. I use schedule 40 composite electrical conduit. There is no problem 
here with a shallow burial. I have just enough depth to conceal the pipe, 
perhaps 3 inches above the conduit. I would try to have the pipe slowly 
angle down from the midpoint to each end to prevent water accumulation. It 
has not been a problem here. I would use a weather hood at the terminations 
to prevent entry of water. Of course do not forget to leave a pull rope in 
the conduit for future additions. I do not use gravel nor perforate the 
pipes. I suspect our rainfall is greater here (central NY)and weather 
conditions generally more severe than So. Cal.








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