I got to get in here,,, this answer is as to how to get the string, rope, etc
through the conduit to pull the cable...
*** Before you pull the Cable through the conduit
First,, if your going to pull cable, always start with at least two
pull ropes in
the conduit. Then when you pull the cable through tie off one of the ropes
at both ends (this is for the possible screw-up), and tie the cable
on the other
rope. I always feed the pull wire down the conduit sections as I
20' at a time, without any problems. Also, keep a little tension on
the ropes as
you pull them through the conduit AND don't twist the ropes, the easiest way
to do this is use a fiberglass "fishrod" and watch what you are doing.
These rods are commonly available at wholesale electrical suppliers and are
the same thing the telco, cable and electrical contractors use to fish wire
through walls, etc.
Feeding 2 wires always gives you a fall back and doing it at the time of
the install saves all the grief of trying the vaccum cleaner sucking,
etc when the conduit is in the ground.
*** Now, when you get ready to pull the cable through the conduit,
AT THE SAME TIME, tie another rope to the cable being pulled through
the conduit, this way you pull the cable AND another pull rope through the
cable at the same time. When your finished you have 2 pull ropes
in the conduit for the next pull.
When pulling the cable through the conduit lube the cable and rope with
"wire pulling lube" like IDEAL YELLOW 77 (ideal pn # 31-358). or if you
want to go expensive, use their teflon additive or auga-gell 2.
hope this helps someone because I've had to follow up someone who
has screwed-up the order and it's a real PITA to do all this after the fact.
Robert Smith Consulting
Wireless ISP's , Government & Commercial Installations
Date: Wed, 13 Sep 2006 21:35:52 -0400
From: Alan NV8A <firstname.lastname@example.org>
Subject: [TowerTalk] Conduit for cables to the tower?
To: towertalk reflector <email@example.com>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
I have questions about the best way to get cables (coax, AC, and
control) from the shack to the tower.
Here are the things I have read or observed and am trying to take into
account. Please correct me if I am wrong on any point.
1. Low-voltage wiring (e.g., for rotor and other control functions)
cannot be run in the same conduit as regular power wiring.
2. All cables should run in grounded metal conduit for effective
lightning protection, according to Polyphaser.
3. The bends in the conduit for a single run of cable may not exceed 360
degrees or it becomes too difficult to pull the wires through.
4. EMT is not buriable. This suggests that RMC must be used, but can it
be bent? Or can liquid-tight flexible metallic conduit be buried, and
does it provide sufficient protection? Is there a means of grounding the
metal in such conduit?
It looks as though I will need three separate runs of conduit: one for
the feedlines, one for power for the crank-up, one for the control
cables and rotator power.
The conduit run for 120V power looks like needing six 90-degree bends
(two too many), and the other cables eight (double the permitted number).
How have others handled their cabling?
TowerTalk mailing list