On Sat,9/24/2016 9:45 AM, Steve Jones wrote:
My full-sized 80M dipole is strung between two Douglas firs. At the end of
the rope over the pulley at one end I use a gallon paint thinner can with
the top cut off and filled with concrete. It rides up and down in the wind
and keeps the dipole taught. Maybe it could use a little more weight, like
a second such paint can.
My 80/40 fan dipoles are up about 140 ft and fed with RG11. Trees
supporting one of the dipoles are about 200 ft apart, the other about
145 ft. It takes a lot of weight to avoid excessive droop. Ropes at both
ends go through a pulley, one end is tied off, the other end has the
weight, which is a 13 gallon water jug filled with dry sand. Weight is
about 90#
The 80M element, which carries the tension, is #10 stranded THHN on one
antenna and #9 hard drawn copper on the other. The 40M element is #12
THHN. The support rope on the longer run is 7/16-in Synthetic Textiles,
the rope on the shorter run is 5/16-in.
These antennas have been up about 9 years. Mechanical connections and
the rope are the weak spots. I've had no failures on the main support,
but did have one side of the 40M element break loose from it's
connection at the center. When I dropped that antenna to repair it, I
rebuilt it to replace the #10 THHN with the hard drawn copper. The other
antenna still has #10 THHN for 80M.
As to mechanical connections. Solder is a VERY BAD idea for wires
outside, especially if the soldered segment of the wire can flex or
vibrate. My electrical and mechanical connections are made using
split-bolt copper connectors. I loop the wire through the mechanical
support at the center insulator, strip enough that it 3-4 inches is
exposed, and use two split bolts to secure it. The split bolt closest to
the center has the wire going to the feedline. At the far end, I use
either two split bolts or two U-clamps (with an egg insulator).
73, Jim K9YC
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