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[TowerTalk] Re:

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Subject: [TowerTalk] Re:
From: (Jim White, K4OJ)
Date: Sun, 12 Apr 1998 17:23:44 -0400
easiest fix to this is to go in at the base of the section - taking
advantage of the top and bottom portion of the legs before/after the
bracing stops. 

I have done this, using an inverted rotor shelf (legs of the plate pointing
skywards) on top of the topmost horizontal cross brace of the section
below.  This necessitates a very long mast - but the plus side is that you
end up having a lot of leverage working for you as far as offsetting the
horizontal forces, and their tendency to make the bottom of the mast move
sideways, that the antennas will put on the mast.  The long boom will have
a fish buzzard land on the end of it, creating a situation where the large
fish buzzard is in essence pushing down on the long lever (boom) which in
turn passes its forces through the boom to mast attachment creating that
desire for the bottom end of the mast to want to move sideways......if the
mast is almost as long below the boom to mast as that the distance the bird
is away from the boom to mast mount the amount of resistive sidewats force
needed to offset the fish buzzard is equal to the force of the birds weight
downward.  If the mast is a shorter length the half the boom then it needs
to be a greater force to offset the damn buzzards weight - for example if
the boom is 40 feet and 20 feet of it is either side of the boom to
mast....the bird will sit 20 feet away from the "fulcrum"...if the mast
sticks ten feet down from there to the rotor then that lever is half as
long and the force needed will have to be twice the weight of the

This means a real pain in terms of putting such a long mast in,
yes......this can minimized as reported extensively on this reflector by
placing you mast inside the tower when you erect the FIRST section of the
tower and then doing a vertical lifting of the mast up through the center
of the tower....

If you do choose this location, I still have had to sacrifice one of the
horizontal cross braces.  Since it is at the bottom of the section close to
the joint, and hence somewhat close to the horizontal brace on the top of
the section below I chose the bottom cross brace. This seems the best
choice to me - but, I am just an amateur 

lets see what the other towertalkians and master of ceremonies K7LXC have
to say, now that Sunday dinner is over, it is time to get back to preparing

the Florida QSO Party, now less than two weeks away!

73, see you in the FQP

Jim, K4OJ

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