My story about a 2" - 20 Foot Aluminum Mast = GOOD !
In about 1965, we installed a 60 foot Rohn 25 Tower with 25G-A2 [the 2"
Opening top section]. We used the torque bars at all 3 levels and
insulated the tower . We later loaded the tower as a verticle. From day
one, we used an aluminum 2" OD THICK WALL ALUMINUM CONDUIT Mast. We
engineered this tower with a Top mtg 2 meter beam @ 15 feet [Top], a 6
El 6 meter beam @ 11 feet [Middle] and a Hy Gain TH6DX @ 6 feet {Bottom]
with the balance of 5+ feet inside the tower 25G-A2 top section to the
HAM-M Rotor on a Rotor Shelf about 5 feet down.. No bearing , sleeve or
bushing used. In late 1990's, a tree hit the tower. A high wind burst
broke a large ASH TREE limb and it whammed into the middle of the tower.
Being an avid DX'er, the beam was used a lot. The point is: The 20 foot
mast responded perfectly without any bends or breaks when it fell on the
roof of my home. The 2" mast did not show any wearing from the throat of
the top of the tower . A little scratching was evident however. That is
a mast that was up for over 30+ years,many wind storms and much aging to
remain in good condition. I have many friends that said they were stupid
using steel pipe mast as most of them were bent from slight to about 90
degrees.
The bottom line is: I will always use a 20 foot, 2" Aluminum mast and
not a steel one. Worked for me. The bigger beams are not in my
experience handbook..
Thanks for listening to my opinion,
Dennis, K5AVT
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