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
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 /-|
| | |
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 email@example.com
. I'll do my best to confuse you completely (:-). (Comments
or corrections also are welcome.)
This is the hit on this
document since 14 August 1997.
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