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.
Bill AD5OL ----- Original Message ---- From: D. Chester <[email protected]> To: [email protected] 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 falls apart. 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. Don k4kyv _______________________________________________________________ This message was typed using the DVORAK keyboard layout. http://www.mwbrooks.com/dvorak/ http://gigliwood.com/abcd/ ______________________________________________________________ Our Main Website: http://www.amfone.net AMRadio mailing list Searchable Archives: http://www.mail-archive.com/[email protected]/ List Rules (must read!): http://w5ami.net/amradiofaq.html List Home: http://mailman.qth.net/mailman/listinfo/amradio Post: [email protected] To unsubscribe, send an email to [email protected] with the word unsubscribe in the message body. 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