Tim wrote:
>I think that the kindest way (to the tree) to fasten an antenna support is
>not to wrap rope or wire around it, but instead to use a 4" or 6" coachbolt
>screwed into the trunk, at 90 degrees to the direction of pull.
>A 'coachbolt' is a large wood screw with a 4 or 6 sided bolt-head rather
>than a slotted head for a screwdriver.
>73s Tim EI8IC
Undoubtedly true, Tim, but very hard to implement at height.
I like w9gtc/1's approach with cinderblocks as counterweights, and pulleys
as high as you can go. Unfortunately, when I commissioned the arborist to
install the pulleys as high as he could in my 120' white pines in VT, he
wussed out at 70'.
That system was good enough for backup, and was used with .250 braided
dacron
line, with 3-5% stretch, and a flattop made of #12 superweave (radioworks
has it)
wire. Lasted 3 VT winters, and now up in MD.
The BETTER antenna, however, was produced by simply flying an arrow over
the tops of the 120 footers, and pulling the rope up. Same system, no
counterbalance, was up for 6 years with no failures. Striking it on
relocation, however, required use of a jeep to pull the rope out of the
pine sap on one end.
While pulleys are undoubtedly better, I have yet to find a method for flying
a pulley haliard, and dropping the antenna haliard down along the trunk of
the tree.
Here in MD, I put up the carolina windom at 75', and replaced the .250 rope
with .125 dacron for reduced visibility. Until I can improve on that hoist
system, if the rope breaks, I'll just shoot another arrow.
Jim, n2ea
_______________________________________________
See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless Weather
Stations", and lot's more. Call Toll Free, 1-800-333-9041 with any questions
and ask for Sherman, W2FLA.
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