Interesting to hear comments on this. This question starts with how much
weight is to be lifted and also what is going to try and pivot if you
release the bottom of the mast from the rotor clamps. Here I have 12 feet
of heavy steel mast above my 2 rotors with large monobanders. For that
reason, I always install the inside tower thrust bearing about halfway down
the 10 ft section that the mast occupies in the tower. I actually let that
thrust bearing float in normal use and only pin it down when doing this type
of work (which also includes dropping the mast for access to the top antenna
- as I am not a mast climber - although I will stand on the top of the tower
to reach something).
So, I believe that unless you only have one antenna on your mast and it is
close to the tower, you should have some way of stopping the pivot of the
mast bottom once it is released from the rotor. If a thrust bearing is not
available in the tower (not on top of the tower), it can be blocked off with
2x4s.
Then I lift the mast up with a come a long securing the steel cable with a
double u bolt. If it's a simple swap then a small lift is enough. If its
dropping the mast down for antenna maintenance, keep in mind the travel of
the steel cable after the rotor is removed. I actually have 2 come alongs
and alternate the 2 as the steel travel becomes a problem during the drop.
Gin poles are for stacking tower sections and putting the mast in the tower.
After that, store your gin pole or lend it to a friend.
Ed N1UR
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