Never use knots for Phillystran! And the Delrin block is "just OK"
for a top boom guy--but NEVER should be used to structurally
hold up a tower.
For such a small tower (40ft of aluminum) if you really want to
use knots--then go to a Dacron rope--ideally a braided rope
such as these ropes--
Certainly more stretch than Philly--but not a problem. I had
a 40 ft aluminum tower with a triband quad up for many years
with this kind of rope. And this was in Colorado with lots of
100+ mph winds. I would suggest going to 3/8 inch as a
minimum--just better to work with.
>During a recent installation of an M2 10 meter 7 element monobander, my
>ham friend who was helping, began attaching the Phillystran from the
>mast bracket to the outer ends of the boom. We used Phillystran instead
>of the nylon twine M2 provides. He brought with him a handful of black
>delrin discs each with 5 or 6 holes in them. By weaving the Phillystran
>a certain way thru the holes, the delrin disc became a clamp without the
>traditional mechanical clamping hardware. And, no rust issues. We
>adjusted the boom to horizontal by use of in line turnbuckles. I can
>get the sketch for these discs if you're interested.
>[mailto:email@example.com] On Behalf Of Jerry Keller
>Sent: Sunday, January 05, 2003 10:38 PM
>To: (Reflector) TowerTalk
>Subject: [Towertalk] Knots for Guys
>There was a lot of discussion recently about knots, particularly the
>bowline for making loops and using when the knot would remain under
>tension. I want to use Phillystran to guy a 40 foot aluminum tower that
>I bought, and I'm wondering if I can use bowline knots to secure the
>line around the thimbles. I would definitely secure the line ends to the
>main line (maybe tape them?) and the guys would be under constant
>tension so the bowlines shouldn't slip.
>Secondly, with Phillystran, would I still include a turnbuckle in each
>guy to allow for adjustment, tightening, etc?
>Last, would I have to use an aluminum thimble at the tower so it would
>not be disimilar metals?
>Advice appreciated.... Jerry