In a message dated 97-04-11 21:29:10 EDT, k0gug@juno.com (Jerry K. Liley)
writes:
> The weight of a mast is very important if you did not plan ahead and put
> it inside the tower at ground level before building the tower or if you
> decide to change masts after the tower is up.
There are two methods of mast installation. The first is done when the
tower is finished and the mast is pulled up to the top and lowered into the
tower. The challenges are the typical mast weight (GRUNT!) and the length of
the aforementioned piece of metal. A 12 foot Rohn ginpole is not rated for
anything heavier than 45G (70 pounds) and doesn't give you enough headroom
for a 20-24 foot mast. Both problems are solved by using a ginpole such as
the WB0W model. It's a very nice professional-type piece of equipment plus
you can use a 15 foot ginpole mast with it. That way you've got enough
headroom to handle those big masts. Now all you have to do is get over the
large pucker factor when you have a BIG mast dangling over your head as
you're trying to install it. Sword of Damacles, anyone?
The second method is to install the mast after you've put the first two
sections together and then pull it up inside the tower after the tower is
finished.
> The 20' or 24' steel
> masts with .25" or .50" wall thickness will really test your metal.
It'll test your mettle as well.
>
> If you have this problem, three inch foam filled fiberglass highline
> poles 20 feet long works as a ginpole. You must rig a way to fasten it
> to the side of the tower and install a pulley on the end but it works.
> A crane would work also $$$$
While an interesting field solution to the mast raising problem, I
don't encourage anyone to try this. I don't trust most hams to tie a knot
let alone secure and rig a homebrewed mast raising fixture. On the other
hand, I do like cranes.
73, Steve K7LXC
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