You are correct, earlier Phillystran had a parallel strand kevlar core
and big grips do not work with it because the cover will easily slip
off. An epoxy filled Spelter (tapered) socket is used to terminate
them. New Philly is constructed like wire rope, twisted lays in a
twisted bundle and the cover won't slip, thus the big grips work.
I don't think there is a big grip for the smallest Phillystran so cable
clips are used, but these must be repeatedly tightened until they cut
through the cover and bear on the kevlar core.
I did come across a Phillystran factory note that shows using swage wire
rope sleeves as an alternative termination to wire rope clips. I have
some boom guys using this technique made by another ham and they look
good, but I don't have any data on yield strength. I'd bet they work
better than wire rope cable clips.
One reason to consider swage sleeve terminations is for yagis that may
be affected by the length of the boom grounded or element connected guy
grip.
The tie wrap provides no strength, just insurance to keep the grip from
unwinding. Ice sliding down a guy can do that.
If you are using wire rope clips then it is nice to terminate the dead
end of the wire rope with a compression sleeve so it doesn't splay out.
Grant KZ1W
On 4/9/2019 18:43 PM, K9MA wrote:
When I put up my tower in 1989, I used 3/16" EHS and big grips. At the
time, I don't think anything was normally placed at the end of the big
grip. Just to be safe, I put a 3/8 inch cable clamp at the end of each
one. That seems to have worked fine. Now I'm replacing the tower, using
the same size EHS and big grips, but I'm seeing inconsistent references
to using "end sleeves". I can't, however, find any explicit instructions
calling for their use. By contrast, the instructions for installing the
big grips on Phillystran specifically call for installation of a nylon
cable tie. (I can see why it might be bad to compress Phillystran with
a cable clamp.)
So my question is: Are the end sleeves mandatory, and, if so, can I use
cable clamps instead. One obvious disadvantage of the cable clamps is
the things can get snagged on them. (Been there, done that.)
FWIW, this time around I'm using Phillystran for the center part of each
guy, with a short length of EHS at the tower end and a longer one near
the ground. I don't think big grips were available for Phillystran in 1989.
Thanks and 73,
Scott K9MA
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