--Original Message Text---
From: W9zr@aol.com
Date: Wed, 14 Nov 2007 17:23:12 EST
I read with interest your comment about running a line between the
tops of 2 tall tress. I would like to do the same but I am not
sure how to mount the support so that the swaying of the trees does
not break it. Can you give me some hints as to how you have
arranged yours?
= = = = = = =
Sure. A VERY old technique in all the ARRL books -- put a pulley at
the top of the tree and rig a weight to the bottom end of the rope
holding up one end of the antenna. You could do that without a
pulley, but the rope would eventually wear where it goes over the
branch and break.
How to get the pulley up there? Throw your fish line or whatever
into the tree using one of the various launching methods, use it to
pull up a heavier pull line, use that to pull up a real rope. Bring
both ends of that rope back to the ground, tie a pulley to it, run
the rope that will support your antenna through that pulley. Now
use the rope HOLDING the pulley to pull the pulley (with the
support rope) to the top of the tree.
I'm sure this technique is as old as the hills, but I learned it
from Ira, K2RD.
For weights -- I went to a good hardware store and bought 6.5
gallon water jugs for about $12 each. Then I went to a contractor
supply yard and bought bags of sand (roughly $3 for 50#). And I
bought a wide-mouth funnel of the type used to put oil in a car. I
used the funnel to help me shove sand into the jug. It's 90-100#
when full, depending on how dry the sand is. Use less sand if you
want less tension. These weights seem about right for my spans and
loads, which are typically 250 ft with a dipole up 110 ft and RG11.
Obviously, you've got to have very good antenna hardware to take
that pull. The cheapie dipole insulators (Radioworks, for example)
won't cut it. The one that DXE sold about 5 years ago but
discontinued was the best I've seen. The one that the Wireman sells
is fairly good, but I don't like the braid nor the way they connect
it. The Unadilla and the Alpha Delta look ok, but I'm not so sure
about moisture.
73,
Jim Brown K9YC
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