I had a crain come and put a hook with a pulley in the trees about 60 
feet up.  We put twine on the pulley so it would make a loop.  Then I 
tied the rope to the twine and made a loop out of the rope.  when we 
put up the antenna, where the rope was tied together we tied a short 
piece of rope.  we pulled the rope up to the top of the tree, it 
would hit the not and stop.  I have an anchor point at the bottom of 
the tree. We put about 6 inches of slack in the rope, and then put 
milk jugs filled with durt to take up the slack.  If the trees swayed 
in the wind, it would pull on the rope and the weight of the jugs 
would bring it taught.  I did that so that if it was really windy, 
the wire wouldn't break.   Befor you put up the pulley, we bent the 
hook so that the pulley wouldn't come off.  It is kind of like how 
you would put up a close line, so it can move.
If I didn't explain that clear enough write back.  Sometimes I know 
the mechanics of it, but not explain it well.
I hope that helps.
Mike Barnard
KD2CDU