I'll just be using a single pulley on each end of the 2 band fans and
one at the 95' level on the 45G, but it'd be easy enough to add more
pulleys so a single rope would tension all bands. OTOH I'm a bit short
on height to match those Redwoods. Still, I don't have to worry have to
worry about that much movement. If it gets that bad the house will be
gone too. I do have to worry about those severe spring ice storms though.
OTOH A tornado only missed us by a few feet less than a decade ago.
Unfortunately it left a big willow tree in our neighbor's yard to the
S. That thing makes a carpet out of half of our back yard. It's huge
for trees around here at maybe 5' - 6' across the base. The wind had it
bent by nearly 45 degrees. The cracking sounded more like a moan turning
into a scream and just as it was starting to break, the wind stopped
abruptly, the tree snapped upright and threw a limb that was over a foot
in diameter over 50 feet up wind into their neighbor's yard to the West.
73
Roger (K8RI)
On 8/12/2016 Friday 2:37 AM, Jim Brown wrote:
On Thu,8/11/2016 10:02 PM, Roger (K8RI) on TT wrote:
5/16ths is over 1700# strength, but a bit more expensive.
FWIW, I use the 5/16-in rope because it's easier to grab hold of to
pull tension on my very high dipoles. 3/16-in (and even 1/8-in) is
plenty strong enough for most antennas that aren't very high.
Wes, N7WS, described a system similar to one I rigged here soon after
I moved here, with help from Ira, K2RD, and others. I replaced it with
the system of pulleys that I now use because it allowed me to get the
antennas higher, and it also allowed me to rig a 20/15/10 fan in line
with the 80/40 fan that had loading coils for 160.
The system that Ira showed me how to rig had a continuous loop of
5/16-in that he launched over a limb with his pneumatic tennis ball
launcher (he cleared the tallest redwood on my property -- about 175
ft -- by at least 10 ft on the first shot). To that loop he attached a
pulley, then pulled the support wire through the pulley, then pulled
the pulley it all the way to the top.
That system survived at least one winter without a weight, because
there was enough "give" in the way the pulley was rigged to allow for
sway, but I'm not confident that the loop rope would have survived
over that limb for 10 years. :) Wes's experience suggests otherwise.
73, Jim K9YC
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73
Roger (K8RI)
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