> I'm in a dilemma.
>
> I purchase a used TM-490 90 ft Sky Needle and recently found some of the
> 5/16", 7 X 19 aircraft cable lifting cable strands broken. The tower is
on
> the ground and not been in the vertical position for a number of years.
The
> problem, apparently there was some gas torch cutting done nearby and
> splatter landed on the cable. This molten metal landed on the pull up
cable
> causing it to burn and sever 2 - 3 strands in one area, and another 3 - 4
> strands 6 inches higher up the cable. The cable overall is otherwise in
> very good condx with no wear marks. It might have been replaced prior and
> the tower has been laying on the ground ever since?
Actually the more basic question is: is the cable out of spec?
Industry standards allow up to 6 broken strands in one bundle so you're in
that
ballpark. Since it's 7x19 (133 strands) steel rope, chances are that the
broken strands are in different bundles so the cable is probably okay. Since
the specs are for more commercial applications where the cable might be
working dozens or hundreds of times a day, a ham tower that gets little up and
down exercise puts much less stress on the cable.
If it were my tower, I'd leave it - too much work and expense involved
for the marginal reliability improvement.
Cheers,
Steve K7LXC
TOWER TECH -
Professional tower services for amateurs
Cell: 206-890-4188
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