What I've done when lifting 100+ pound antennas is to run the lifting
rope down to a pulley low on the tower, then back up to the top. I then
wrap two slings of smaller rope around the lifting rope with Prusik
knots. One sling goes to the come along, which pulls UP on that section
of rope to lift the antenna. The come along goes where I can reach it
when working on the antenna. The other sling goes above the first one,
attached to the tower with a carabiner, both as a safety and to secure
the rope when it's time to let out the cable on the come along.
Note that the lower pulley sees twice the load on the lifting rope, so
make sure it's secure.
I've used this scheme many times when assembling antennas on the tower.
(Which I have to do due to space limitations.)
73,
Scott K9MA
On 11/14/2019 08:30, Jim Thomson wrote:
Date: Wed, 13 Nov 2019 12:26:10 -0500
From: Dave Sublette <k4to.dave@gmail.com>
To: kj6y--- via TowerTalk <towertalk@contesting.com>
Subject: [TowerTalk] multi-sheave pulley
<The trouble is, at age 77 I no longer have the arm strength that I once
<had. So, I would like to use a multi-sheave system to reduce the force
<necessary to lift it off and reinstall it. I have a two pully system which
<would reduce it to half, but I think I had better go with a three or four
<section system.
<All this to ask what is a good three or four sheave fully? It only need be
<a two inch diameter. Or, a one inch would work also. If you have any
<knowledge which one and where to get it, it would be appreciated. In the
<meantime, I will do my own searching. But, I thought it would be good to
<have the input of someone who has actually used what they recommend.
<As always, I look forward to the excellent advice that comes from this
<group.
<73,
<Dave, K4TO
### Use a ....cumalong. Easy, and much better control vs a lawn tractor.
http://ds-studio.co/cumalong-tool/ The 1st pix, is the version I have.
It has
the 2nd hook option..... so you double up on the cable....so its
only half
as long, but capacity increases from 1 ton to 2 tons. You then also
get
an even finer adjustment for a given amount of lever pull. An 88 lb
rotor
would be a piece of cake.
## I use a multi sheave / rope setup to get a yagi to top of tower,
then the same
cumalong to do the last few inches. Grnd crew lifts yagi up to top
of tower, then I
hook the cumalong to a 2nd quick rls shackle. Grnd crew then goes
home. I lift yagi
the last little bit.... then....using my hb version of the infamous
F12..easy on mounting
scheme, mate the horz boom plate to the already installed vert mast
plate.
Jim VE7RF
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Scott K9MA
k9ma@sdellington.us
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