[TowerTalk] Antenna Rope report

[Jim Brown]

More comments from my experience over a couple of years. 

I bought several thousand feet of the very nice black sheathed 
dacron rope (with a white center) sold by Davis RF (and others). I 
installed about half of it at W6BX, hanging wire dipoles between the 
top of the tower and ground stakes. I also used some of it at home. 
The rest has not been used. My observations are:

1. Moderate sun bleaching over a period of two years. 

2. This rope does not hold up to being run through pulleys or over 
anything that can cause wear. The two biggest wires at W6BX both 
fell to the ground after the rope broke at the top. One fell in less 
than a year, the other six months later. Note that this is a 
mountaintop QTH (see qrz.com) that gets fairly high winds. I note 
similar wear at the home QTH.

3. Generally nice handling characteristics. 

Conclusions:  This is nice rope, but I wouldn't use it anywhere that 
it will be subjected to any form of wear, and I would expect the sun 
to cause failures after 3-5 years, depending on the weight being 
supported. At W6BX, we've replaced the upper rope/pulling rigging 
with Phillystran. We're still using the rope on the bottom ends, 
which are not subject to the wear. 

A parallel observation regarding the super flexible, finely stranded 
copper being sold by Davis RF as antenna wire. While it's "nice," it 
doesn't hold up at all. Some wires at W6BX that used the #12 version 
fell apart in less than 6 months. The strands break at the ends 
where they are tied off. Our wires are now 3-wire parallel dipoles 
built using #10 solid copper for the longest dipole that supports 
the weight and #12 standed THHN for the parallel dipoles. All wire 
was purchased at Home Depot. We "hard drew" the #10 by tying it 
between the towing hook of our truck an a telephone pole. There have 
been no failures of these antennas so far. 

I'm also preparing for a move to CA, where I will be rigging lots of 
wires from lots of redwoods (we'll own 8.5 acres). I would 
appreciate advice from those who have successfully done so, 
especially with respect to the support ropes. I will have access to 
a local guy who climbs the trees and will install pulleys (without 
damaging the trees). I may use the dacron rope for the low end of 
sloping wires, but not at the top where it goes through the pulleys. 

Jim Brown K9YC