I've had to do 3 re-cabling jobs. One a 72' UST where one of the cables
was so bad it broke. One a 89' UST where the cables had more than
surface rust and had more than the 6 strands broken rule of thumb. One a
105' Triex that belonged to a cell phone company that was worse than the
89 footer and was just before breaking.
It's not easy but if you take your time you can work your way through
it. I will mention that not all the cables can be pulled through by
attaching them to the just removed cable due to the fact that the Nico
press (sp?) clamps won't pass through the sheaves so they must be
removed. The other thing I've learned is that the tension on the pull
down cable must be set with some weight on the top section of the tower.
Steve would you agree with this?
Julio, W4HY
-----Original Message-----
From: towertalk-bounces@contesting.com
[mailto:towertalk-bounces@contesting.com] On Behalf Of K7LXC@aol.com
Sent: Tuesday, June 06, 2006 9:17 AM
To: towertalk@contesting.com; DrD@2020.com
Subject: Re: [TowerTalk] Help Needed Replacing Crank-Up Cable on US
Tower
In a message dated 6/5/2006 9:02:43 A.M. Pacific Daylight Time,
towertalk-request@contesting.com writes:
> I just purchased and have brought home US Tower, model HDX-572MDPL,
> 72'
Heavy
Duty tower from the estate of a SK.
> It has a motor drive whose design includes a postive pulldown
> feature.
> The tower contains 4 sections, was installed in 1999 and has had
> little
use.
> Where I need help:
> US Tower recommends replacing the cable every 2-3 years, which may
> be an
overkill but is definitely erring on the side of safety. Since my
tower is 7 years old I'd like to start out with fresh cabling.
The UST recommendation is known as a "weasel clause"; that is, if
something happens to your tower and you hadn't changed the cables, they
can weasel
out of any liability. Tower manufacturers are insurance-driven
enterprises so
it's no surprise they are reluctant to provide any helpful information.
The other gotcha is that there isn't anyone around who can do the
cable
change anyway. I spent a couple of days at the factory to learn how to
do it
and what I found out is that it's an involved and semi-complicated
endeavor.
It's not something I would try myself.
I'll bet you a nickel that you don't have to do anything other than
lube
the cables and you'll be good to go. The actual circumstances that
would
require cable replacement are: 1) Excessive broken strands. Industry
standards
allow you to have six broken strands before replacement is necessary.
2)
Excessive rust - not surface rust but real cancerous into the strands
rust. 3)
Damaged cable. This would be kinks or flat spots in the cable. I doubt
that your
cables meet any of the above criteria.
OTOH you should lubricate the cables annually at a minimum. Champion
Radio
Products sells PreLube 6 which is recommended by the wire rope
manufacturers.
You should exercise the tower a couple of times a month by running
it up
and down. You should also park it at different heights rather than just
at
the limit switches all the time. The cables can take a permanent set by
sitting on the pulleys at the same spot for years. By doing these 3
things, you
will prolong the service life of your cables.
BTW I have never personally seen a ham tower that the cables were
so bad
that they had to be replaced. Some were pretty grungy but didn't meet
the
aforementioned criteria.
Lube it and enjoy it and don't worry about replacing the cables.
Cheers,
Steve K7LXC
TOWER TECH -
Professional tower services for hams
Cell: 206-890-4188
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