I have the Mast Raising Fixture from US Tower for my HDK-589. You might be
able to use that if you rather not homebrew a solution. It mounts on two
holes in the lower top plate, and the cable runs down a third hole, where it
attaches to a collar around the mast. The collar is loosened and
repositioned as required when the mast is raised or lowered. It's shown on
page 7 of http://www.ustower.com/uploads/pdf_file/HAM%20CATALOG.pdf.
Jim N7US
-----Original Message-----
I am thinking about possible rotor maintenance on my new tower. I will be
lifting a 22 foot mast and antenna stack onto the tower with a crane and
nesting it 4 feet or so into my Rohn 45 tower. I will have a thrust bearing
on the top and an Orion 2800 rotor 4 feet below the top thrust bearing.
I am thinking of setting a second bearing plate just above the rotor which
will be about 4 feet below the top thrust bearing. I will have a TB3 bearing
on it. I may well lift this bearing off the plate and clamp it to the mast a
few inches above the plate so that I don't have alignment issues. The
bearing just sits in the air above the plate. When I want to remove the
rotor I should be able to lower the bearing, bolt it to the plate and add a
clamp to the mast so that the mast rests on this bearing or will the bearing
stop the mast sliding down. Some sort of u
bolt or a saddle clamp should work. The stack and mast will weight about 220
pounds.. I should be able to remove the rotor
then with the mast held in place. Yes it's more money but it makes it
possible to remove the rotor and repair it without dealing with the stack.
I am still thinking this out but I want all the pieces fabricated and
checked out with the tower on the ground first
Mark N1UK
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