[TowerTalk] Underground conduit question

Wed Feb 9 05:09:46 PST 2011

Hi Guys,

I used standard-issue-variety black pvc pipe that allowed me to bury some
15' - 20' of feedline & rotator cable from the base of my tower, to the
shack window in the basement...

I specifically did NOT use the pipe with the leaching holes in it---and in
order to keep water from gaining entry at either end, I used elbow joints
there, such that the cables are actually facing the ground when they enter &
exit the pipline "tunnel."

After some 3 years, I can honestly say, "So far, so good." And I no longer
have to worry about nicked lines when I cut the grass in the area come
summer...

~73~ de Eddy VE3CUI - VE3XZ

******************************************

----- Original Message ----- 
From: "Al Kozakiewicz" <akozak at hourglass.com>
To: <towertalk at contesting.com>
Sent: Tuesday, February 08, 2011 8:58 PM
Subject: Re: [TowerTalk] Underground conduit question

> I've seen countless posts in various forums regarding the perforation of
perfectly watertight pipe to aid "drainage".  Do people get that much
airflow through their buried and sealed pipe that condensation is a major
problem?
>
> I can tell you that where I live in upstate NY, if you bury perforated
pipe below the frost line or, for that matter, more than a couple of feet
deep, it will fill with water and stay that way forever.  I'm no expert, but
I kinda think that's worse than some condensation!
>
> Al
> AB2ZY
>
> -----Original Message-----
> From: towertalk-bounces at contesting.com
[mailto:towertalk-bounces at contesting.com] On Behalf Of Daryll Webb
> Sent: Tuesday, February 08, 2011 1:27 PM
> To: towertalk at contesting.com
> Subject: Re: [TowerTalk] Underground conduit question
>
> Howdy   I like this group!  Good stuff all around.
> Hr is what I plan to do with my install.
> As the feed line will be direct bury, not submersible! I plan to use the
plastic pipe that is used for leach beads, it has drain holes in it.
> That way if any water gets into it I think it will drain as it is suppose
to. A thin layer of sand or pea gravel should make it work.
> It will only need to be 12" deep or less jest to keep it from coming up
after a few years.
> If I need to change cable I hope to hook the new one to the old one and
pull it in as the old is pulled out.
> In theory it should work. Wish me luck  Daryll kg9nd
>
>
>
>
>
> ________________________________
> From: Peter Dougherty <w2irt at verizon.net>
> To: towertalk at contesting.com
> Sent: Tue, February 8, 2011 12:10:14 PM
> Subject: Re: [TowerTalk] Underground conduit question
>
> On 2/7/2011 1:55 PM, Peter Dougherty wrote:
> > Hi all,
> > Several years ago I had a run of 4" solid white PVC tubing run on a
> downward
>
> Very important...How long is this run and how deep.
> It's roughly 41 or 42' long, buried about 18" down at the deep end and 12"
> on the shallow end. It was installed when an electrician put in a 120 VAC
outlet for our nearby pond. These three pictures can describe it better than
my words can:
> http://s291.photobucket.com/albums/ll290/W2IRT/Towers%20and%20Antennas/
>
> Snow won't hurt, it's just a nuisance.
>
> >>IF the conduit maintains a grade all the way it won't fill up with
> >>water and freeze. This part I'm afraid to ask. What did you use to
> >>block the end
> in the
> >>yard to prevent "critters" from turning it into a ready made home?
>
> I used 1/2" wire-mesh (hardware cloth) fastened by a hose clamp. The
cables run through the squares.
>
> > After the lines emerge from the conduit they just run over top of the
> ground
> > to their respective antennae. After a coax failure to my loop, I tried
> > pushing a fish-tape through the conduit in hopes of running a new
> > length
> of
> > cable but it became obvious that the inside of this conduit had gotten
> > ice or muck inside, so I need to wait until spring to try and remedy
things.
>
> >> If there are more than a few cables in the conduit and/or it's a long
> >> run it'll be very difficult to push a fish tape through it once it
> >> has cables in place.
>
> If you look at the pictures referenced above, I have a number of cables
that exit the house and then go up to the vertical section just a few feet
away (which now has a 180-degree cap on it) and to an antenna switch box
mounted on the side of the tower. One line (the 160 antenna) comes back down
that riser and along the full length of the conduit. I have 3 or 4 other
cables that run the full length of that conduit (the failed K9AY coax, the
control line and a run of RG-6 for a noise sense antenna, which has just now
been repurposed as the K9AY coax).
>
>
> > This now leads to a few much broader questions.
> > 1) Can I do anything to improve the drainage of the existing 4"
> > conduit (remember, it's already on a downward angle)? Digging up the
> > back yard is NOT an option.
> How deep is it. With cables in the answer is probably not. If the conduit
is "always" on a grade with no low spots it should not need any more
drainage.
>
> I'm *pretty sure* it's on a constant albeit shallow angle down away from
the house.
>
> >> You could build a box for the cables to exit into at the end of the
> >> conduit.  Put some plastic mesh in it along with a few mothballs to
> >> discourage critters.
>
> I think this is the way I'll go, similar to what our sprinkler-system
installers did for their junction boxes and valves, etc.
>
> > 2) The coax/control-cables lying on the ground will need to be buried.
> Do you mean the ones coming out of the current conduit?
>
> Yes, the lines to the K9AY loop specifically, although I'd like to bury
the 160 TX antenna feedline as well. It, however, traverses a lot of very
inaccessible terrain (behind rocks, beside an embankment, through a narrow
gap between the garage and a concrete fixture, etc, making that job far more
difficult. That ground rises and falls considerably, too.
>
> >> Have you considered "direct bury" cables?  Or something rugged like
> >> Davis BuryFlex(TM) and just leave it on the surface or buried shallow?
>
> I guess this is the way to go for the 160 TX, and maybe for the K9AY. I'm
using direct-bury sprinkler control cable for the K9AY directionality
control and remote power so no worries there. I'm not really a fan of
direct-bury, though, since if there is a failure I'd rather just pull a new
run in minutes rather than either a) dig out the old one or b) dig a new
trench for the new one. I'm definitely interested in a conduit solution.
>
> [pjd] -pjd
>
>
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