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1992-05-11
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3KB
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88 lines
SUBJECT: Tower Series, part 3
TREES: Trees have been used as antenna supports for years. There
are some problems though. Trees grow, they have leaves or needles,
they sway and are probably the greatest target for lightning than any
man made device.
I have used trees for an antenna support many times. In my CB days,
I cut the top off an oak tree in Connecticut, thrirty-five feet up, and
used chimney straps to hole a mast for a 'Starduster' quarter wave
antenna.
Here in Florida, I use a palm and a sycamore for a DX-A (40, 80,
& 160) and the same sycamore and a small maple for my 40 IVee. Both
are fed from my tower. I have a pulley system to raise the antenna I
need for specific operations.
* sycamore
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* palm
* maple
<--------North
Trees must be cared for when attaching support lines. Too tight and
you can strangle the branch or worse, the tree. Never use a dead tree.
They're an accident in the making.
Beams in trees are not a good idea. Getting them up there is a
pain in the butt to say the least save a crane. Constant upward growth
interfers with the pattern and the ability to turn them thus requiring
pruning. Pray you don't have a problem like bad SWR, bent elements,
or a water soaked trap.
I would suggest keeping trees for verticals or tie off points.
------------------------------------------------------------------
WOODEN TOWERS: These can be interesting. They are heavy, can rot,
and don't stand much for the weather. Wooden towers are subject to
many enemies such as bugs, birds, and rain. The sun can dry on out in
two seasons. A wooden tower creaking in a 50 mph storm can give an
amateur nightmares. They are expensive to build with todays pricing
on wood.
Simple fold-over wooden towers such as a flagpole design, can be done
if the materials are availble at a resonable price.
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||||||<--- pivot point
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||||||<--- Locking pin (bolt)
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This set up can be done in a day with the right materials. The
main pole can be pulled up with a pick-up or car. A stop bar is
recommended so you don't pull the main section over with the vehicle.
Place the stop bar just above the locking pin and bolt it into the
main section but not the supports. It also can be cranked up with
a boat winch from the bottom.
-WS