There's a diagram of how to do this on page 10-21 of my book. You
should have removable trailing lines on each end of the beam, so it
won't rotate as it goes up and foul the guys. Also, you should be
sure that the antenna center of gravity is below the boom, so it
won't tend to turn over as it goes up.
There's a great pulley you can get at REI, which is about 4" diameter.
It has two independent side plates that are held together with a
caribiner when installed, so you can get it over the tram catenary.
I also build the antenna hanging from the tram, as it gets it up
out of the walking way. And it is easy to pull it part way up to
check everything, and you can also bring it near the tower so you can
reach the element ends to tune the match (I tune the rest of the
elements with a hacksaw at assembly, now that the modelling software
has come good, with good scaling and tapering models, etc.).
Yeah, I use my own taper and element mount models :)
I don't like to use a power winch or truck to pull up anything, as you
can pull the whole mess apart if anything hangs up. Also, I don't like
using hand pulling, because you can drop the works if someone lets
go. So we use hand-cranked ratchet winches (I haven't found a worm-
drive winch yet) with great sensitivity to hangups. When you get the
antenna to the mast, it's easier to release the far end of the tram so
the antenna drops down right next to the mast. Be sure you get the
tram and pulling cable on the right side of the boom for removing or
installing!
I use a sailing snatch block at the base of the tower so the winch is
located at the same point as the ground end of the catenary cable, which
is tensioned with a come-along (be sure you know how to release it, so
you don't get caught with too much load at the middle).
Good luck, happy and safe climbing! I go up after the antenna has
arrived at the top, but sometimes you need to guide it.
73 de Dave, W6QHS
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