Without quoting back the whole thread, here's what I've done so far. The
tape goes in about 3 feet or so and just stops quite suddenly. I'm using
greenlee fish tape, very solid steel and about 1/8" wide. I cut the hook off
to prevent it from catching on anything and just kept poking at various
points around the circumference of the conduit. It managed to go in another
foot or two but that was it. It looks like the blockage is right under the
riser portion of cable. Likely snow got blown in (despite the 180-degree
sweep), melted and froze.
At this juncture I'm not going to do anything until the spring. I had one
run of RG-6 in there for a sense antenna leading to an MFJ-1026. I
disconnected the sense wire, put in an F-barrel, added 35' of RG-6, an
F-female-to-PL-259 adapter, a double-female UHF barrel, soldered on a PL-259
to the short end of the cable from the remote box and it worked good enough
to let me bag the VP8 on 160 last night. I've just used Scotch 130 around
all the hardware but I will go out and double-wrap in Scotch 88 tomorrow if
I'm a little less sore and a bit more flexible!
I think the best solution is to just pull out the bad cable and tie on some
1/4" rope once the better weather arrives. I will definitely replace the
existing coax with BuryFlex and I will also take the occasion to run a new
length of 160m TX coax as well (also will be BuryFlex).
My real concern is how to put in the conduit in the "back-40," from the end
of the existing conduit to the base of the remote box, as described in my
original post. Unlike the run across my back lawn, this continues to slope
downwards on average, but undulates a little in the middle. In other words,
it's not a straight run, and the general course is downward, away from the
house. When the original conduit was put in, that little digger made easy
work of the one-foot-deep trench. I won't have that luxury this time and the
back area has far more sub-surface boulders and tree roots than the existing
conduit. In other words, I wanna do this right the first time and not set
myself up for even more nightmares over the next few winters.
------
- pjd
-----Original Message-----
From: towertalk-bounces@contesting.com
[mailto:towertalk-bounces@contesting.com] On Behalf Of Rroger (K8RI on
TowerTalk)
Sent: Tuesday, February 08, 2011 9:41 PM
To: towertalk@contesting.com
Subject: Re: [TowerTalk] Underground conduit question
On 2/8/2011 12:10 PM, Peter Dougherty wrote:
> 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/
Looks like a neat installation.
A couple of things to try.
Remove the grid from the far end. With some one on both ends, can you
move that piece of coax, or any of the cables in the conduit. If you can
move the bad piece you have a ready made messenger cable. Tie/tape a
piece of 1/4 to 3/8" nylon or Dacron rope to the failed piece of coax
and pull it into the conduit by pulling the bad piece out the other end.
Alternatively: There should be some play in the cable, not much but
maybe a 1/2" to 1".
When you slide the fish tape in, I assume you are going in from the
basement end. When the tap stops going in, does it get steadily more
difficult, or does it stop abruptly? If it get more difficult as it goes
in which it should, you might try having someone take hold of the cables
at the far end while easing the tape in. When the going gets tough move
the cables back and fourth that inch or so while maintaining pressure on
the tape. Conversely you can move the tape back and fourth with the
cables, but add extra force to the tape when the cables move forward.
Often the cables get wrapped around each other forming a spot that will
catch or restrict the movement of the fish tape. there may be a low spot
where water has collected and frozen but it should not fill the entire
conduit. It may OTOH guide the end of the fish tape into a "blind end",
or trap it where cables are caught in the ice.
There are several types of fish tape ends. The one I have is like a
bullet with a slot cut in it and it rotates. The more common kind have
the end bent back to form a kind of clip. Some times I start wrapping
the end with tape to form a double taper, then grease it up "liberally"
with that well known "wire soap" or "wire pulling soap" I may have
mentioned.
IF OTOH the fish tape stops abruptly, note how far in the conduit its
gone. Try rotating the tape and you move it back and fourth about an
inch or two. That would indicate it had caught on something or caught at
the junction of some cables and ice. Try coming in from the other end.
If it stops again note how far in it's gone. The two measurements
should give you and idea as to how long an area is stopped up and
possibly where you *might* have some ice, a nest, or tangle of cables.
IF you suspect ice, borrow a hair dryer and blow warm air though the
conduit for several hours. Be really careful about temperature. That
is why I didn't recommend a heat gun. One is OK, but keep the temp at
120 degrees or lower. You might have to plug off the stub going to the
tower by stuffing a towel or making a foam plug.
IF you can not move the cable, nor get air through the conduit, it
either has a nest in it or it's plugged with ice. and you may have to
wait for warm weather.
If you can pull the one cable out, inspect it thoroughly. If you find
indications of chewing on it, or indications there may be a nest in
there, it'd be a good idea to pull out all the cables for inspection. I
had never had rodent's chewing on the cables in nearly 50 years from
various locations, *until* last winter. They chewed through two RG-6
cables that go to the satellite dish. Those cables were exposed from
the box on the tower down to the grounding block (which is still about a
foot above the ground) They chewed through about half way between the
box and grounding block which was actually a bit under the snow.
> 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.
I'd suggest a finer mesh. If you can get RG8 through, mice can get
through. They can get through unbelievably small spaces. I've seen
them disappear through tiny openings as my big cat was closing in<:-))
73 and good luck,
Roger (K8RI)
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