In a message dated 98-05-22 15:08:59 EDT, BILL.MADDOCK@fluordaniel.com writes:
<< I will be trying to raise a 24 ft long mast 2" OD 1/4" wall to the top
of my tower Rohn 45. The mast is already inside the tower it will just
need to be raised up! I have a Rohn 25/45 ginpole, will this be strong
enough for the job or should I look for another means? The mast weighs
about 130 pounds. >>
The easiest thing to do is to hang a pulley on a horizontal rung at the
top of the tower and run the haul rope through it and then run it down the
inside of the tower. Attach the haul rope to the mast about 1/3 down from the
top of the mast with a sling choker. Wrap it around the mast 2 or 3 times and
pull it through itself and it'll never slip.
Attach a pulley at the bottom of the tower and run the haul rope through
it. This is called a snatch block and changes the direction of the haul rope
run from vertical to horizontal. Since you will need 260 pounds of pull to
hoist the mast (130 pounds up the rope inside the tower and 130 pounds down
the rope on the outside of the tower), you'll need a lawn tractor, winch or a
bunch of friends to pull it up.
When the mast reaches the thrust bearing, guide it in and through until
you run out of haul rope. Tighten the TB bolts to capture the mast. Now you
can move the choker down the mast (all you have to do is take tension off the
choker and it'll slide). Have the ground crew put tension on the haul line,
loosen the TB bolts and they can continue lifting the mast up. Keep going
until you can slide the rotator in under the mast. Install the rotator, lower
the mast into the rotator and then tighten the rotator mast clamp. You're
done.
If you want to install antennas on the mast before you hoist it up fully,
feel free. Mount the antenna and feedline pigtail, hoist the mast up, mount
the next antenna, etc.
The other option is to install the naked mast and then climb the mast
with angle iron or aluminum steps pushing the antenna(s) up as you go. (This
is an advanced technique.)
Cheers and GL, Steve K7LXC
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