[TowerTalk] Clamps and Phillystran

[alsopb]

Your information is old.  The current "best practice" is to use
preformed big grips of the "correct size".  Texas towers sells the
cable and big grips.

Regarding GM use of clamps.  Even their tallest tower (70') only uses
1200# kevlar (phylistrand) with a preload of 120 pounds. Rohn 25 uses
4000# phylistrand and 400 pounds preload.  Screw in anchors are used
as opposed to concrete imbedded ones. The tower base concrete section
is considerably larger than for Rohn 25 (4'X4'X4' for a 70' tower). 
The aluminium tower has a 16" face for the 50 and 70' designs. It's
pay me one way or another.  Personally, I like the ease of
installation (no holes/concrete for the guys) and the skinny, light
phylistrand guys which disappear into the background.  I also like the
tower and base absorbing most of the horizontal load.

GM has done studies showing that for their application cable clamps
are perfectly adequate.

By the way, if you want to be shocked,  cut open the 1200 or 4000#
phylistrand cables and count the number of Kevlar fibers.  You can do
it on two hands.

73 de Brian/K3KO

Henry and Kate wrote:
> 
> All this talk about clamps and Phillystran has me a bit concerned. It was
> my understanding, based on an information sheet I get with my Phillystran
> orders, is that the only ways to terminate the stuff is with potted ends
> (older style) or with Big Grips.
> 
> Any use of clamps with Phillystran is counter indicated and is dangerous.
> 
> To comment on clamp application methods, the manufacturer of the clamps
> will have an application sheet that details the correct orientation,
> spacing, torque and holding force for the product.
> 
> Again, it's a case of the "Prime Directive" being applied.
> 
> end
> 
> Henry and Kate
> KB7RTA and KC7GTU
> kate@rio.com
> 
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