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.
> slope from my basement, under the finished portion of my back lawn then
> opening out into an un-maintained part of the yard in which my receive loop
> and 160 TX antennae are located. All was thought to be well until I realized
> that the lower portion (at the base of a large tree and a small embankment)
> gets swallowed up by snow and ice after the first storm and stays like that
> until spring.
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?
Critters that just love to chew on coax and rotator cables. If you use
foam you need to put in a small drain hose so condensation will not
collect. Steel wool works great where it stays dry, but not out in the
elements. Fiberglass insulation works for some, but some mice appear to
not be bothered by it.
> 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 did not include a pull or messenger cable in the conduit you may
have a problem. You did say that one coax failed so you could use that
as a messenger or pull cable to pull in a real messenger. When you
finish make sure there is a cable in there that you can use to pull in
additional cables if needed. I use a cable/rope length a bit more than
twice the length of the run. That lets me make a pull and then pull the
rope back for another one while always having a messenger in the conduit.
Here are a few of the methods I've used to a tower. You could mount a
box on a wood fence post just as well.
the conduit has some small (1/8") holes drilled in the bottom near the
base of the tower and near where it turns up to go into the box on the
house. http://www.rogerhalstead.com/ham_files/cablebox.htm
> 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.
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. BTW Yellowjackets (Nasty tempered little members
of the wasp family) also like places like that conduit or a box at the end.
> 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?
> That
> ground doesn't slope at all, and it fact undulates slightly. How can I put
> in conduit for this run that drains properly and won't allow ice buildup?
Have you considered "direct bury" cables? Or something rugged like
Davis BuryFlex(TM) and just leave it on the surface or buried shallow?
> 3) Does it matter if I use white drainage PVC pipe or grey electric conduit
> (all low-voltage)?
Not really.
> 4) Anything that I haven't mentioned here that I should consider doing, or
> potential gotchas?
Critters using the conduit for a home and a messenger cable!
> Thanks in advance!
>
Good luck es 73.
Roger (K8RI)
> ---------------------------------------------
> 73 and Good DX
>
> Peter,
> W2IRT
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