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Erecting Long Masts

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Subject: Erecting Long Masts
From: (RobertKing)
Date: Thu, 19 Dec 1996 16:15:44 -0500
Adam, Re: your thread, Eerecting long masts.

I have a HG-70HD crankup here-with a TH7DX at 72' and a home brew 3 el 40
meter yagi
13' above it.  Before raising the tower vertical, I slipped a 2" od 3/8"
thick wall aluminum mast of 6061-T6 into the tower. Yes, I know its only
36,000# strength! In addition, I slid the hy-gain rotor plate down to about
6 feet from the top of the tower.  Another plate was made from 3/8" 6061-T6
aluminum (galv steel would wrk) and installed it 2 feet down from the top
where the original plate was to be. On this plate, I put another thrust
bearing-home brew copy.

At the time, I didn't realize I had done the proper thing to lessen the
lateral forces
on the rotor housing. However getting to your question about inserting the
rotor thru
the nested tower sections where a RCH would "barely" fit, I found it
necessary to
crank the tower to a point where the rotor plate is about 1 foot out of the
last section.  At that time, for safety, I insert 1-1/4" steel pipe between each
of the overlapping tower sections and downcrank until there is just some
on the safety stops. Then I don my safety belt and scale the tower with the
hardware, tools etc. to do the job.

I'm well aware of the danger in climbing crank-up towers, however I have not
the least bit hesitant to do it when the sections are blocked with steel pipe. 
With your shorter 3 section HG-52HD, it should be much easier to do. I use an
extension ladder to get to the over-lapping points.

My homebrew 40 meter yagi weighs about 50# on a 32 foot boom. At 83' its a
decent pile buster! By the way, 3 feet of mast is above the 40 for trussing.
Been up since September 1992 and through some 50-60mph gusts just a month
still straight!!!!!!

By the way, I've had the rotor in and out 3 times in the past four years.
The last
"in" was last Friday. Back to control from the shack and no more running out to
swing the antennas with a rope! The Hy-Gain T2x rotor is going to be replaced by
a Create RC5A-3.

Good luck on your project. Don't know if anything informative has been presented
here but thats the only way I found I could do mine.

Merry Cristmas,


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