ust returned from a business trip to find my 80 meter dipole on the ground.
There has been no severe weather here since last winter. Upon inspection of
the failure mode, I found the rope had broken about half way between the
pulley and the ground.
I use the 770 lb UV jacketed dacron rope for all of my wire antennas. I
inspected the whole length of the rope, plus the two other halyards that hold
up the other wire antennas. This rope is new and has been in the air less than
a year. I offer these observations as another wrinkle in "what can possibly go
wrong."
There are a number of galvanizing "tits" on the bottom section of the Rohn 45
tower. Since they are not in spots that are hazardous to hands or feet, I've
never bothered to knock them off. The jacketed dacron rope has an affinity for
snagging on those tits, however. Until now, I never really paid much attention
to the snagging issue.
It appears that, in each spot where the rope has snagged, the UV jacket has
separated and exposed the inner dacron core to the sunlight. The UV is so
intense here in the mountains, the dacron has deteriorated and broken. I offer
more supporting data in that I used a handful of non-UV resistant ty-wraps
around the coax switch box at the base of the tower and they have deteriorated
and broken in less than 4 months.
Another vote for using UV-resistant coax and rotor cable!
Tom, K5RC/7
Virginia City, NV
www.ConsultPR.com
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