My crank-up(aluminum) has stop blocks that engage at each horizontal brace.
Its spring loaded so going up is hands off, coming down you have to manually
release it by pulling down on a rope. When it is all the way down there are
blocks welded to support each section. I always take the tension off the
cable whether its up or down. I also use pre-lube, so far so good. If I
couldn't have a crank-up I couldn't have a tower.
See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless Weather
Stations", and lot's more. Call Toll Free, 1-800-333-9041 with any questions
and ask for Sherman, W2FLA.
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