My old Wilson rotatable has two small bolts that serve as set screws to clamp
the mast in
the tube.
Tighten the two bolts is SUPPOSED to stop mast slippage.
But I was always reluctant to really crank down on them for fear of breaking
them off or
stripping them out.
I really didn't want to drill out the chrome moly mast either.
The recent 40 mph+ winds in Chicagoland had me 'correcting' for windage
frequently.
So I finally came up with a design that was cheap, easy to install, and seems
to have
solved the problem of misalignment.
I got two small 'clip angles' from work.
These are 4" long 4X4 wide angle irons, about 1/4" thick.
I drilled two sets of holes for 2 1/2" U bolts in one and two sets of 2" U
bolts in the
other.
The 2 1/2" clamp piece was put on the mast insertion tube.
The 2" clamp piece goes around the mast.
There will be a slight difference in position due to the 'insertion tube on the
tower'
being a larger size than the mast, but the two clips angles should line up in
the
horizontal plane.
I then clamped them together and drilled two 3/8" holes through the horizontal
plates.
Make sure the antenna is properly oriented and bolt the two plates together and
tighten
all the U bolts.
Fortunately for me, my Wilson tower is right next to the large chimney on my
roof so I
could stand on the chimney and easily do the final drilling and tightening.
Hope this gives someone an idea on solving a similar problem.
In my case, where the rotor is mounted at the bottom of the Wilson tower, this
does not
add appreciable strain on the rotor.
In the case of a top mounted rotor, you may want to consider the slippage vs.
rotor damage
before adding my clamp system.