In a message dated 12/21/2006 10:41:35 A.M. Pacific Standard Time,
towertalk-request@contesting.com writes:
> Thanks to all for your feedback, both on- and off-list. I have traced the
practice of using a short EHS leader at the tower back to the original
method of attaching the Phillystran to a thimble.
The easiest way to attach any termination to something is to use a
clevis (also called a shackle). It'll handle back-to-back
terminations/thimbles
with no problem.
I can't think of a reason to use steel cable at the top of the tower
before the Phillystran part of the guy.
> In the early days there were no Big Grips, so the Philly was terminated
using four cable clamps. These clamps created a potential snag point for
ropes used to haul items up the tower. Now that Big Grips are available,
the need for this leader has been eliminated.
In the early days was the original Phillystran that used potted end
terminations. The current stuff has a softer PVC jacket that is primarily
for UV and abrasion resistance. There was a couple of year timespan before
Preformed grips were available so the only termination available was cable
clamps. The reason they're not recommended now is that the amarmid fibers of
the
Phillystran would cold flow from the compression of the clamps, creating a
less
than optimal and potentially problematic termination.
There are also little aluminum caps available that go over the end
of the bottom grips (facing up the guy). They are supposed to prevent ice
that's sliding down the Phillystran from unwinding the grips. I've seen tie
wraps
used for the same reason although they could get ripped off in extreme ice
conditions.
Cheers,
Steve K7LXC
TOWER TECH -
Professional tower services for hams
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