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SUMMARY: Burial of CATV Hardline

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Subject: SUMMARY: Burial of CATV Hardline
From: (Charlie Ocker)
Date: Thu, 5 Sep 1996 14:58:17 -0500
On the 28th of August, I posted a query to the reflector seeking =
comments on
the best way to bury 3/4" 75 ohm CATV hardline.  I neglected to mention =
in the
original posting that the cable in question does not have any outer =
material over the aluminum.

Thanks to all who responded.  The responses were mixed.  Some said to =
bury it, others said to bury it only if it has a protective jacket, and =
said to put it in some PVC drainage conduit.

Charlie  KD5PJ/9
=46rom KB4LBX:

I am a tech for Prestige Cable TV here in the Atlanta area.  We use =
and "650" feeder and trunk able.  Which is 1/2" and 3/4" and now we use =
trunk!  This cable is very well at home in the ground.  We always bury =
trunk in the sub-divisions here and they are abt 18" deep in red clay =
stones!!  They are good and we run our system at 400 mhz and we have a =
of <1 dB per 100' on channel 52 (391.455 mhz) and <.04 loss per 100' on
channel 2 (54.455mhz)  Again, burying the cable is ok.
=46rom AA7TF:

If you want to bury it, put in inside some PVC/ABS. That is what we did =
at NK7U's place. It actually is not that bad the first time through. =
you do is dig the holes, layout all the coax and control lines you think
you will need, add a couple for unplanned additions if you can afford
it and a pull line. Then, you pull the sections of PVC over all the =
at one time. Tieing a rope or wire to each PVC section sure makes it =
to drag the PVC sections along. Then you glue the sections together, =
them in the hole, fill it in and off you go. If you need to add lines
later the pull rope will do the job. I agree the idea of pulling a half =
lines through 100' of pipe is not appealing. At NK7U we have PVC runs
supporting 4 towers anywhere from 50 to 200'+ from the wiring closet. We
really hope we don't have to pull a bunch of new lines through them. The
key is good planning up front -- like many things in life.
=46rom WA0PUJ:

Bury it.  That is what the cable companies do.  I just buried 660'
of 3/4" CATV to my new 160M vertical last weekend.  We have VERY
rocky soil/sand here.
=46rom K2WK:

My contact within the local cable company who supplies me
with 1/2" & 3/4" CATV hardline says that the bare Aluminum
stuff CAN NOT be buried.  The direct burial stuff has a PVC
(or some such thing) on the outside.  The bare cable will
soon turn to Aluminum dust is exposed to corrosives found
in most soils, and in most rain these days.
=46rom VE1SPC:

I have a simular setup here.
        The tower is about 65 feet behind the house on a hill (up). I =
two lenghts of 1/2" 50 ohm hardline in a pvc conduit and ran an extra =
run of
conduit for rotor feed line and can run another run of hardline or a =
runs of coax. I felt better about the protection of the hardline in the
ground and with the conduit there I am ready for additions or changes
without digging up the yard again.. hihi
        Pulling the hardline through the conduit wasn't easy but was =
worth it.
If you pull it through before you bury the conduit it may be easier, I =
bury the conduit first, with someone pulling a line through the conduit =
someone pushing the hardline it didn't go too bad.
        I hope this helps you, here at my home the soil is simular as =
and the ground freezes in the winter, which was a concren..
=46rom N4ZR:

I have the same stuff Charlie, and hesitated to bury it - mine goes in =
conduit under the lawn, and on the surface across the field to my tower.
I'd be interested in the collective wisdom.
=46rom NO9Z:

I was faced with the same question.  I used 7/8 inch heliax...50 ohm, 2=20
cables and put them inside 4 inch thin wall sewage pipe.  The cost was=20
not a big deal, plus I ran the rotor cables, antenna switch cables and=20
another rg213 as well.  All for the price of 1 conduit.  gl 73 Lynn
=46rom K1VR:

Does the hardline have black PVC cover?  If so, you may bury it.  The
"armored" direct burial hardline is armored because stones migrate and
crimp, crinkle and break hardline.  Your aggregate is a problem, so take
good baseline measurements on loss, so that if you suspect something
someday, you'll have those baseline measurements to refer back to.

Another approach:  Dig the trench by hand and back fill without rocks
(screen them out) or backfill with sand.  Or just buy some cheap white =
and don't even worry about sealing it.  That way, any water that gets in
will seep out.

I have some armored, some direct buried black covered and some in 4" =
They all work.  But I made sure that there were no stones.
=46rom WJ0M:

If your CATV hardline has a vinyl type covering you shouldn't have any
difficulty.  I had the unprotected =BD inch variety buried for over four
years without problems. but let me relate a story told me by the Cable
TV folks.  They had a run that went under the roadway of a bridge over a
swampy river, and used the uncovered stuff.  The corrosive action of the
water etc. caused the shield to break down in less than a year and they
had to replace it with something more impervious. =20

If you have a sufficient amount of hardline, I'd recommend a second run
as a spare.  I did that and, because I hit the hardline with a mower
where it exited the ground to the tower, I ended up using the spare.
=46rom K0SD:

   You didn't tell us if it has black coating on outside, or if it is
bare aluminum?  I've typically suspended mine overhead from a line with =
a post=20
or two along the 100 ft plus run.  I definitely wouldn't bury bare
aluminum.  If I had it to do over, I would probably bury six inch =
sewer pipe just below the surface with T's every so often that let me
reach down in the run and work with things.  Put a cap on when not
working with it to keep out water and animals.
=46rom WB9TIY:

Don't bury it unless it's jacketed and designed for direct bury.  If =
it's not,
you'll be sorry in a few years...

I've got a couple of runs to pull through about 100' of buried pipe, =
before winter.  I'll let you know if it's a disaster - I feel it's going =
to be.
I think I'm going to use 6" corregated PVC drain pipe and pull it in 50' =
BEFORE I bury it, along with a messenger rope.  Then I can pull easier =
like control and rotor lines through any time.

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