Preventing Wire Antennas That Are Attached to Trees from Breaking in the Wind
 
         by Daniel A. Grunberg   --   Kensington, Maryland U.S.A


When I was a teen-aged ham, I used to anchor one end of my wire
antenna to a neighbor's tree, and the other to a sturdy fence.
The antenna was made of hard-drawn copper wire.  Hard-drawn wire
is stiffer and not as easy to work with as the more usual
soft-drawn wire, but hard drawn wire is structurally more robust. 
[Actually the recommended wire was Copperweld, a copper plated
steel wire, but I couldn't afford it.]  Sometimes we had strong
sea breezes in Brooklyn, so I had to find a way to allow the tree
to sway without breaking the antenna.  My Radio Amateur's
Handbook suggested two things:  


1.  Instead of tying the insulator directly to the tree, the
Handbook suggested cutting the rope and inserting a reasonably
stout spring.  The antenna would be raised (on a calm day) with
sufficient force to elongate the spring somewhat.  Then as the
tree swayed toward the antenna, the spring would contract, but 
the antenna would remain reasonably taut.  When the tree swayed
away from the antenna, the spring would expand, but the antenna
would not break.  

           R    I           antenna         I   R  Sp  R
       |-------o=o-------------------------o=o-----uu------|
       |                                                   |
    Su |                                                   | Su
       |                                                   |
       |                                                   |

          I is an insulator      Sp is a spring
          R is rope              Su is a support (e.g. building)
 


2.  Instead of tying the insulator directly to the tree, the
Handbook suggested that a pulley should be attached to the tree. 
The antenna would be hoisted (on a calm day) by a rope running 
over the pulley.  The free end of the rope would be weighted
(perhaps with a paint can or cans full of sand).  The weight 
would be tied a few feet above he ground.  Then as the tree 
swayed, the weighted rope would ride along the pulley and keep 
the antenna taut but unbroken.

       |   R    I           antenna         I   R      P /-|
       |-------o=o-------------------------o=o---------(*) |
       |                                                 | |
    Su |                                               R | | Su
       |                                                 W |
       |                                                   |

          I is an insulator        R is rope
          P is a pulley           Su is a support (e.g. building)
                                   W is a weight 


It seems to me that I used both antenna supporting methods at one
time or another, and that both methods worked.  Perhaps one 
method or the other might keep your antenna from breaking in
another high wind.  




This article was last updated on 14 August 1997.

If you have any questions, feel free to Email me ce369@freenet.carleton.ca . I'll do my best to confuse you completely (:-). (Comments or corrections also are welcome.)



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