[TowerTalk] Water in Conduit...

[Jim Thomson]

Date: Wed, 4 Mar 2015 21:34:54 -0600
From: "Perry K4PWO" <k4pwo at comcast.net>
To: <towertalk at contesting.com>
Subject: [TowerTalk] Water in Conduit...

I still don't understand the "French drain" stuff.  I have a 70' run of two
3", one 2.5", and two 11/4" conduits from my tower to my house. At each end,
I have the conduit terminated in metal 18" X 16" X6" NEMA 4 boxes.  The
boxes allow the conduit to breath and in the seven years they have been
installed, all I've found in them is cob webs.  I just pulled some Cat 5E in
one of the 11/4" runs and it was as dry as a bone. 
Like a lot of the Southeast we are currently in the middle of a freezing
lake... flood, then ice, finishing with snow. In other words a lot of
moisture.  If I had used the "French drain" my coax coax would be swimming. 

Perry K4PWO

##  The problem with using that pvc pipe that has the rows  of holes on each side is..
its meant for perimeter drains.... to allow water INTO the pipe.   For ham use, the 
pipe would have to be flipped 90 degs..so the holes are at 12 and 6 oclock...to allow
water out the bottom holes..into some gravel bed etc.  Trbl is.... it will also allow water
in through the top holes!   You would be better off to buy pipe with no holes..then drill
ur own holes..at  6 oclock only. 

##  On a similar note, the telcos, power and cable companies all use pvc pipe..
with no holes at all.    Each end of the pipe is terminated correctly, and the entire 
length can breathe.   Never saw one with water issues in it.   Telcos used to direct bury
a lot of stuff..in residential areas.  That stopped a long time ago.  Cable goes bad, 
and has to be replaced.    That requires ripping up every driveway and boulevard 
up and down the street.   When the replacement cables started to go bad, and a 3rd
was required,  city hall read em the riot act..... no more direct bury.  Everything
has to go into pvc pipe..and big diam stuff too.  

##  a lot of problems with ham installs is..too small a diam pipe is used....and down the
road this  will bite you.  Flip side is.... trying to remove a cable, when several are already
inside the same pipe is a real pita at times, with cable sheaths burning on each other. 
Cables should be  lubed  before install.  How long the lube will last is anybodys guess. 

##  Plan B would be to install several pipes at the same time... at least two.   With coax
in one..and control, misc and any power cables in a 2nd pipe.  Use control cables with plenty
of spare conductors.   You might even want to run spare coax cableS  as well..at the same
time, then cap off the spares at each end.   Its actually easier to run all the intended cables 
at one shot..all at the same time.. vs 1 cable at a time. 


##  if running cables laid on top of the ground, that split loom, corrugated  tubing,
installed over top of the cables will allow for a certain amount of protection. 



Jim   VE7RF