Reply:
Motorized up/down. Hand crank to tilt it over.
No pull down. Somewhat staggered positioning on the support arms,
mine are not Wilson made. The "loops" are ty-wrapped and taped so the
coax(s) physically support/appear as one cable.
The tube rotates so the rotator
is at the base and no rotator cables go up the tower.
On raising & lowering the tower is in full view and
the "loops" are carefully watched for any problems
although I don't recall having any snags. It is a problem
to mount a dipole off of! 73 Robert W5AJ
& I see the 9913 does not go up the tower. That run ends at the
switch box at the tower base. The MFJ 259B measures loss on the
140feet run of 9913 and assorted other switches in the shack
at 1.6 dB @ 28mhz to the RCS-8V box.
----------
From: Dick Green <dick.green@valley.net>
To: Robert W5AJ <w5robert@blkbox.com>; towertalk@contesting.com
Subject: Re: [TowerTalk] Coax for crankup
To: <towertalk@contesting.com>
Date: Wednesday, August 12, 1998 12:26 AM
(snip)
I have an old Wilson 77 manual and they recommended dressing the coax in
loops as you did. But U.S. Tower told me not to do that on my 72' rotating
motorized tubular. The current model of my tower has several obstructions
that can snag the coax loops: a set of limit switches mounted at the top of
the bottom section and some guide pulleys for the positive pulldown cable.
They recommend letting the coax drop through the eyes in the coax arms.
Before I talked with them about that, I tried loops with LMR400UF. The coax
twisted all over the place and wandered around the tower. It looked like
the
upper loops could snag on the limit switches, guide pulleys, and even the
other coax arms. I also thought one or more loops could twist enough to
tangle into a knot when the tower was raised. Since I do this remotely,
where I can't see what's happening with the coax, it just seemed too
dangerous. It only took one or two experiments raising and lowering the
tower to be convinced that it wouldn't work. I think it would work better
if
the coax arms could be staggered around the tower, but that would put some
loops right where they could snag on the raising cables or pulleys. The
LMR400UF is very stiff and the jacket isn't very slippery, so it's possible
that loops would work better with RG/213 or 9913F.
Someone with a Tri-Ex triangular crankup told me that the loops generally
work on that tower, but that he had to attach ropes to the coax and
sometimes use them to pull the loops away from each other and the tower
when
cranking up.
I take it that your tower isn't motorized, doesn't have limit switches or
pull-down cable guide pulleys, and that you don't raise and lower it
remotely. True? Are the coax arms staggered? Do you ever have to "help" the
loops to keep them from snagging on something as you raise the tower?
73, Dick, WC1M
-----Original Message-----
From: Robert W5AJ <w5robert@blkbox.com>
To: towertalk@contesting.com <towertalk@contesting.com>
To: <towertalk@contesting.com>
Date: Wednesday, August 12, 1998 12:56 AM
Subject: Re: [TowerTalk] Coax for crankup
>
>I use both RG-213 and Flex 9913 on my crankup tube.
>A Wilson 77 footer.
>My coax is banded the length of the bottom section. It is connected to
>the top of each extension section on coax arm so when it is descoped there
>are coax loops hanging in the air. Nothing on ground level to
>worry about the lawn mower hitting and some coax support along the way.
>
>73 Robert W5AJ
>
>
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