With only four more sections to stack on my new 110' Rohn 55 tower, it's
time to start thinking about how I'm going to install the antenna and rotor
at the top.
I'll have a 40-2CD on the mast just above the top plate. The top plate will
have a TB-3 thrust bearings, and there will be another TB-3 thrust bearing
on a shelf between the top plate and rotor shelf. As is common practice, the
second bearing is there to facilitate removal/replacement of the rotor, so
its screws won't be tightened against the mast during normal operation. The
rotor will be a Tailtwister.
My question is this: should the full weight of the mast and antenna be place
on the rotor or top thrust bearing? If I put the weight on the rotor, then
I'll have to jack the mast up a bit to remove the rotor, whereas if I put
the weight on the thrust bearing I can remove the rotor without raising the
mast. But it seems to me that it may not be such a great idea to have the
weight of the antenna and mast supported only by the three screws in the top
thrust bearing. What's the general consensus on this?
If the answer is to put the weight on the rotor, then it seems to me that
I'll have to do the final adjustment of the bearing screws after installing
the 40-2CD, not when I install the mast. In other words, after installing
the antenna, I'll have to loosen the bearing screws so that the extra weight
of the antenna is transferred to the rotor. Is that right?
73, Dick WC1M
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