[TowerTalk] Big Grip Installation

[Grant Saviers]

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
>