> Gary,
>
> ON4UN describes how he does exactly what you want to do...put the rotor at
> the ground. See any of the last two editions of Low Band Dxing. There are
> many advantages to having the mast go up throught the tower stabilized
> with
> bearings.
>
> As far as installing it, I'd suggest doing it while the tower is going up,
> or alternatively (if the tower is already up) having a mini crane do the
> job
> from the top. That way you could use 20ft sections.
When I installed the 97' 45G I build a Ginpole that is about 22 - 23'. This
allowed me to tie onto the 24' lengths of pipe a bit *Over* half way up. I
added a half hitch near the top of the pipe to keep it straight.
http://www.rogerhalstead.com/ham_files/tower.htm Photo of the ginpole top
about half way down the page.
With me on top and a friend pulling on the rope to the ginpole it was a
relatively easy job to take the 24' lengths of masting (standard pipe and
structural steel lengths are 24', or at least all I've seen) up to the top,
swing them over (ginpole top swivels) and let the pipe down through the top
of the tower. This last part is where you really need to watch fingers and
toes.
BTW, I ran the tope to the ginpole through a pulley at the bottom of the
tower so any workers did not have to get under the load being pulled up. I
also used two pulleys with one on the top and the other floating on a loop
of the rope tied back to the top for increased mechanical advantage. It
makes it a lot easier, but it also takes a *lot* more rope!
Good luck on getting the pole inside the tower.
Roger Halstead (K8RI and ARRL 40 year Life Member)
N833R - World's oldest Debonair CD-2
www.rogerhalstead.com
>
> Remember to have some kind of torque absorber in the system, and a way to
> secure the mast when you service the rotor.
>
> For a rotor I would recommend a small size 90v dc motor, a 2 stage Boston
> Gear worm drive, and the Green Heron controller. Another option would be
> an
> old Prop Pitch...but the equipment is very old now. You can build a
> superstrong rotor from scratch using over-the-counter industrial parts.
>
> 73, Scott W3TX
>
>
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