Dan's comment is very true of *any* antenna, and most especially tree mounted antennas.
To survive storms at all, it's very important that the antenna wire or the halyards *never* fall under strain from the tree as it moves in the wind. Even small trees can exert tons of pressure on the wire or halyard. I have an Inverted L with the end attached about 50 feet up in a 60 foot high Spruce tree. Two counterweight systems maintain sufficient tension on the antenna to keep it in place while allowing the anchor point in the tree to move at least 15 feet in high winds. One counterweight allows the main antenna end guy rope to change length as needed as the tree moves and the other allows the back stay that loops over the tree to move independently. The counterweights need to be heavy enough to hold the antenna, but not heavier than needed for that. When trees whip in the winds, the inertia of the counterweights can produce shock loads many, many times greater than the weights themselves for a brief moment until the weights begin to move. The heavier the counterweight, the greater its inertia and the shock load. My antenna survived two storms with hurricane-force 100+ MPH winds last winter, although the antenna counterweight did move almost its full travel as the tree swayed more than 10 feet at the 50-foot level. This summer I adjusted the system to allow more movement. Even so, the system needs to come down every couple of years to be inspected for chafing of the lines and to move the lines somewhat if you don't want them to damage the tree. Dan's suggestion is an excellent one. No sense in starting from scratch if the worst does happen! A few feet of extra line can make all the difference in the world. If we humans have learned anything at all, it's that anything human kind can erect nature can knock down! Ron AC7AC -----Original Message----- ... and, HOWEVER you get the ropes over the tree, they will someday fall. If the location is a "good one", you may want to use it again. Rather than trying to hit that perfect branch again, I always include an extra rope, for after the fall. The "extra rope" is a continuous loop that reaches the ground and does not bear any weight. It is used simply to pull a new rope/antenna up after the current one falls. It looks like I have three ropes over the branch, but one holds the antenna and the other two are just both sides of the "backup" loop. I usually do my antenna launching in the winter when foilage is less, but the things come down whenever they please. With a loop over each "good" branch, I can pull up new rope/wire even in the middle of summer. Dan / WG4S / K2 #2456 _______________________________________________ Elecraft mailing list Post to: Elecraft@mailman.qth.net You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
