At my last installations I chose option 1), and as I lowered the tower, I
guided the coax bundle into a circle on the ground. I added an angular
support to the topmost stand-off arm so that the weight of the whole bundle
was better supported. I had 6 RG-213 coax cables, rotator, and a control
line for 80/75 relays on a dipole. The coax bundle was taped together about
every two feet.
I saw a really neat installation at N6EK a few years back. Bob had a large
washtub inverted on the ground. He had applied the right twists to the
cable so that it coiled rather naturally around the washtub all by itself
when the tower was lowered.
73 de Dick, K6KR
-----Original Message-----
From: TowerTalk [mailto:towertalk-bounces@contesting.com] On Behalf Of Larry
Loen
Sent: Monday, November 19, 2012 7:22 AM
To: towertalk@contesting.com
Subject: [TowerTalk] How to deal with Coax on a Crankup Tower
Slowly, but surely, my tower project is making progress.
Got a lot in place or will shortly finish. Tower is mounted, grounding in
place, A/C power. It's getting real.
Now it is time to consider a homely little problem I have given no
significant thought to: Routing the coax up and down the tower as I crank
it up and down.
The tower's manual gives me no explanation on the coax stand-off arms that
come with it. It states helpfully that when I install them correctly, they
will line up top to bottom. That was OK and expected. What is not obvious
is exactly how, exactly, the coax ought to "travel" on the tower.
The standoff arms themselves seem to consist of an open loop that has room
for several coax to be in them. Good as far as it goes. But, it seems to
admit to two designs.
1. Let the coax freely fall the whole 60 to 70 feet (this will vary based
on the three coaxes I will be running up the tower). The cable would be
"guided" by the standoffs, at least as far as the tower, proper goes.
2. Fasten, in some manner, the coax to each stand off. There would be a
modest amount of slack when the tower was fully extended and more when it
was not.
At the W0IBM club station, which had basically the same tower, the second
option was chosen. It would be using 9913 F for my runs, so that the coax
would be largely in the air. As at W0IBM, it would simply form a graceful
and natural loop between each standoff when the coax descended (I'm pretty
sure the W0IBM tower used RG8 or something flexible -- no 9913F back then).
I could also attach the DC control wires for the rotor to the coax as well
(I presume).
If I chose the first option, which the design of the stand offs kind of
superficially invites, the coax would have to "pool" at the bottom of the
tower, and it would do so in a place that looks rather unfriendly for the
purpose.
It seems "obvious" to me that the second should be chosen, and yet I don't
remember seeing much discussion about this. Or, details about how to attach
it.
Assuming the W0IBM solution is the right one (it would also help frustrate
the local copper thieves, too), how do I attach the coax to each stand off
and do so in a way that helps fight off the Arizona sun, which does things
like bleach "caution" tape in about a month's time?
Larry Wo0Z
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