From:
Fred Hopengarten K1VR 617/259-0088
Six Willarch Road
Lincoln, MA 01773-5105
permanent e-mail address: fhopengarten@mba1972.hbs.edu
On Sat, 13 Sep 1997 17:51:56 -0400 "Robert C. Boyd"
<w1vxv@mail.biddeford.com> writes:
>I am about to put the coax cables and rotor cable underground. Has
>anyone used
>schedule 40 PVC for this purpose, and how has it stood up?
I just came in from digging a trench for my next run of Schedule 40 white
PVC, which I am burying just down enough to prevent damage if someone
ever comes along with a rototiller (i.e., I'm digging a trench about 22
inches deep, so that the top of the pipe is 18 inches below grade.
Before you start digging, be sure to buy a tool for cutting roots, and be
sure to have a pick of some sort handy to help loosen the earth and to
dislodge rocks.
I have three other PVC 40's buried, and they have been underground since
1982 without worry.
A few other tips: Place a #14 wire (stranded, insulated) in the pipe (as
a rope could die from moisture related problems). Make the wire two
lengths of the pipe, run it around a pulley, and your life will be easier
forever. As some point the cables in the pipe will get twisted. It's
not your fault. To add the next cable will require that you back out ALL
cables, add your next one and then pull them all through together. At
this point you may consider adding a second pipe. But pipe is cheap, so
you may further choose to put the second pipe in while you put in the
first. Pipe is VERY cheap, and you will be older when the next need
arises.
Figure out a way of sealing the end which is outdoors. I wrap VERY thick
plastic sheet (former waterbed liner or waterbed bag) around the end and
tighten it with wire. Little animals will want to get in and settle for
the winter. A field mouse will pack in chestnuts and leave behind
unspeakable filth. Seal up the field end. This is the voice of
experience speaking.
Also seal up the house end. This prevents a field mouse from getting
inside your house through the pipe. In the winter, it also prevents you
from trying to heat 150' of pipe buried underground.
I don't glue the pieces of pipe together. This allows any water that
gets in to get out. It also makes any subsequent changes (a Y, for
instance), easier to execute. Plus, the pipe is not carrying any liquid.
Why bother?
Last -- do not use 90 degree elbows. They are very hard to pull. Use
22.5 degree or 45 degree turns. And bring up an access to the pipe (a Y
which heads UP, above grade) just before you enter the house, so that if
you have a cable coming from a different direction someday, you'll be
able to get it into your house easily.
Burying feedlines and control lines make the back yard look neat. May
have some lightning benefits. Lessens opportunity for the lawnboy to
damage it, lessens opportunity for the landscaper to damage it. Makes it
hard to move your shack once installed.
Good luck! -- Fred K1VR
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