Mike's tower sounds like the shaft broke and not a gearbox failure. On
the older MD-750 motor drives, the shaft was 1 inch coming out of the
gearbox. (Tristao and then US Tower). US Tower then went to a larger shaft, 1
or 1 1/2, don't remember which. Have not seen any of the newer ones fail.
There is a lot of tension on that multi groove pulley, especially when
hams have a tendency to overload their tower. It's not just wind load but
weight. Those towers have a weight limit. Add it all up, mast, rotor,
antennas, cables, etc and I'm sure you'll see more weight then you thought.
Regular maintenance and inspections should be done.
Skip, _KJ6Y_ (http://www.kj6y.com/)
_Communications Service Co_ (http://www.communicationsserviceco.com/)
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