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[TowerTalk] Phillystran and Pulleys

To: "Tower Talk List" <>
Subject: [TowerTalk] Phillystran and Pulleys
From: "Jim Brown" <>
Date: Mon, 22 Jun 2009 09:57:42 -0700
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I've got some of the smaller 1,200 lb test Phillystran that I bought 
years ago for a wire antenna project that didn't happen. It's too 
small for the 120 ft Rohn 25 that I'm preparing to install, but I'm 
wondering if it would work on my high dipoles that are up 110 ft in 

The existing antennas, 80/40 fans fed with 150 ft of RG11, are held 
up by ropes (the "good" stuff that DX Eng and some other ham vendors 
sell) through good pulleys, but the black UV sheath of these ropes 
gradually abraid from friction as the trees sway, and eventually they 
fail. A 5/16-inch rope holding up my 160M Tee vertical failed after 
two years -- the sheath wore through completely, exposing the inner 
white material. Luckily I discovered it before it rotted in the sun 
and dropped, and was able splice in a new rope and pull it through. 

I'm not worried about the pulling strength, which is certainly 
adequate, but I am concerned as to whether the Phillystran would 
stand up to continuous flexing at the pulleys as the trees sway in a 
storm. Each antenna is counterweighted (about 100#) at one end, 
pulleys at both ends. 

Thoughts? Experience?  


Jim K9YC


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