K5PGW Wrote:
I do have one additional "question of the day" and that is if you
have had any experience in installing a tailtwister rotator near
ground level by running a mast from the top of a Rohn 25 tower about
70 feet tall so that the rotator might be changed or worked on from
near ground level? I know it has often been done, but I am not sure
of the type mast, thickness of the material to use and how much
bellying of the mast might occur. I have large thrust bearings that I
can place near the top and strategically down the tower to prevent
sway and bellying of the long mast. That would also take all weight
off the rotator as well as as control the sway and bellying of the mast.
You may see this as an ambitious project for a 70 year old, but I
DESERVE IT after over 50 years as a HAM. Your support and
encouragement is greatly appreciated. 73, John, K5PGW
-0-
John,
W3GM had six 100' Rohn 25g towers, all of which used a ground mounted
rotor.
Ham 4 and Tailtwister, as well. They were turning things like a 3
element full sized
40m yagi. The "mast" was 2" irrigation pipe. Wasn't particularly
heavy, nor thick
walled. The idea was that the mast would torque, and deflect some,
absorbing the
peak torque loads from the big arrays. I think he had 2 or 3
accessory shelves on
each tower, with thrust bearings for lateral support.
So, it's been done, and it's worked for many, many years.
Jerry Mathis was older than you, and still working on his arrays, and
able to lay over
all his 100 footers using a falling derrick & 4 way guys.
Good luck!
Jim/N2EA
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