[TowerTalk] Long shaft to base mounted rotator

[Roger (K8RI)]

I think we may have beat this subject to death last year, but I'm having 
trouble finding it for reference.
I was looking at a tower a nearby ham is getting ready to install. He 
has built a very nice, sturdy base which holds the PST-71 and the tower 
mounts on top of that base. My concern is the shaft that runs between 
the rotator and the antenna some 80 feet above it.  The shaft is 2" 
steel tube with an 1/8" wall while the antenna is one of the big multi 
band yagis.  I don't remember the make but think the model ends in a 
56.  The thing weighs over 200#.  I think that is a lot of inertia for 
that 80' of tubing to handle and that tubing may end up acting like a 
large spring/torsion bar.  It just doesn't look adequate to me.

Any thoughts?

Roger (K8RI - ARRL Life Member)
www.rogerhalstead.com
N833R (World's oldest Debonair)