|[AMRadio] Seeking advice on "wires in trees"|
bguyger at sbcglobal.net
Wed Apr 29 12:46:00 EDT 2009
The johnny ball idea is a very good idea, but if you use a pulley, go to a marine supply house and get one designed for sail boat rigging. They're expensive, but also bullet proof. They just work.
----- Original Message ----
From: D. Chester <k4kyv at charter.net>
To: amradio at mailman.qth.net
Sent: Wednesday, April 29, 2009 11:35:54 AM
Subject: Re: [AMRadio] Seeking advice on "wires in trees"
I would never use a pulley, springs or weights. Use some good, heavy duty
UV-resistant rope. Instead of a pulley, use a medium size "johnny ball"
strain insulator, like you would use on guy wires. Don't use the smallest
size. Attach the insulator to the rope that goes across the limb, just as
you would a guy wire, and securely tie the rope. Then run the rope that is
attached to the end of the antenna through the hole. Pull the first rope
until the insulator is just a few inches over the limb and firmly tie it
down. Now pull the antenna rope, letting it slip through the hole in the
insulator until the antenna is as tight as you can get it. If you leave
too much slack and sag, it will bounce all over the place and likely shake
itself apart in a windstorm, and sometimes the feedline can manage to tangle
itself up with anything else it can.
The insulator has no moving parts, and if the ropes are inserted properly,
about the only thing that could go wrong would be to break the insulator,
which is unlikely since they are designed to handle at least 3000 lbs.
The rope just slips through the hole over the glazed porcelain. Pulleys
have a bad habit of freezing up over time, or the rope derails off the
groove at the edge of the wheel and manages to bind between the side of the
wheel and the frame of the pulley. Or the whole thing rusts over time and
The spring is even a worse idea. If it doesn't stretch out in a windstorm,
it will very quickly rust in two and break.
The rope over the limb should not be able to slip back and forth. That will
wear the rope in two and cause chronic damage to the tree as well. Better
to let the tree limb grow over the rope with time, and use the insulator for
the antenna rope to slip through.
Generally, it is a bad idea to tie the rope or wire round a tree limb if
that can possibly be avoided. This may eventually cause rot to set in and
you lose the entire limb or even the tree. If you can climb up to the
point of attachment, a better idea is to get a hot-dipped galvanised (not
zinc-plated) threaded eyelet with about a 1/2" diameter threaded rod and
about 3" longer than the diameter of the limb, drill a slightly larger hole
all way through the limb, insert the eyelet through the hole, and secure it
in place with galvanised washer and two nuts. Use the first nut to hold the
eyelet, and use the second nut as a "pal nut", torqued down tightly against
the first one, to avoid the possibility of the first nut managing to unscrew
itself from the eyelet.
They also make eyelets with a shank like a wood screw, which will work if
you can get them screwed most of the way through the limb, but that may be
easier said than done. I have found it easier to pierce a hole with a
cordless drill and use the nuts and washer method of attachment, especially
while hanging onto a tree limb at 40-50 ft. in the air. A good climbing
belt is highly recommended.
When I had my antenna in a tree, I could climb to where it was attached, at
both ends. I had better luck using #10 copperweld wire for the antenna,
good *heavy duty* insulators, and attaching the antenna rope directly to the
tree, pulling it as tight as I could, and permanently fastening each end so
nothing was slipping through anything or over limbs. During windstorms, the
antenna would actually hold the limb stationary and the feedline would
bounce around less. That antenna stayed up at least 5 years before I had to
re-do it. With rope looped through the insulator or over the limb, I could
count on putting the antenna back up after every heavy windstorm, at least 2
or 3 times a year. But flimsy wire and/or antenna rope will break.
This message was typed using the DVORAK keyboard layout.
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