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[TowerTalk] Coax in Conduit and WATER!

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Subject: [TowerTalk] Coax in Conduit and WATER!
From: (Patrick Lynd)
Date: Sun, 06 Jul 1997 13:08:50 -0700
Joe E. Mesh wrote:
> Some time ago...   I read an Andrews publication about burial of coaxial
> transmission lines.
> In the publication they reccommended ONLY direct ground burial where
> burial was planned. Specifically they advised excavation to ten inches
> or more below the frost line.   Six inches of small porous stones with
> rounded corners line the base of the bed.   Four inches of fine sand
> follow.  The cables are then to be laid in the hole and covered by two
> to three inches of fine sand followed by the backfill.
> The purpose of all this is to provide a "french drain" and remove the
> build up of water in the coax.
> They specifically advised not to ever use conduit.   A local friend who
> services commercial radio stations antenna sites, pager sites, and cell
> sites, also recommended against using conduit.   He states that when he
> pulls the coax for replacement after problems develop or a lightning hit
> -- he has never found the conduit encased coax dry.  It is always wet.
> He is adamant that regardless of how the conduit joints have been sealed
> they leak.   Similarly the direct buried conduit splice done with
> connectors always leaks without regard to the manner or amount of
> sealing performed.
> The man has twentyfive years of experience directing five crews of tower
> and antenna workers performing installations and repairs five days a
> week.   I have to listen to him.
> What is your point of view on these issues?
> Joe / W8SS
> --
> Thanks....Joe E. Mesh, D.M.D.,C.A.G.S.(Prosthodontics)
> from Beautiful Downtown HELL, Michigan USA
> 07/06/97      15:15
> _______________________________________


Even seamless and joint less conduit gets wet on the inside. Water will
always find a way in. Assuming that one could even find a way to prevent
water from entering the conduit condensation will form inside the pipe
and create moisture in underground applications.

Conduit was never meant to be moisture protection it was meant to keep
critters from chewing on the wiring and as a means of pulling lots of
wire through the same route.

Patrick Lynd (AC6YD) 

HELL, Michigan? I know about St. George Utah, where it's said that
because of the heat all the people have two homes, one in HELL and one 
in St. George. They rent out the house in St. George and live in HELL.

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