For 80m I use 20 feet of Rohn 25 which sits on 3 plastic insulators
(poly rod, turned down to fit inside the Rohn 25 legs at the bottom).
The Rohn is
guyed with poly rope, and serves as a gin pole to lift 48 feet of 2-inch
.058 wall tubing. The 12-foot tubing sections are spliced together with
6-foot sections of 1-7/8 inch tubing slipped inside (3 feet overlap
above and below the joint). When the 48-foot section is upright I use
brackets and U-bolts to attach it to the Rohn tower sections loosely.
Then I push up the tubing 12 feet or so and tighten the U-bolts. The
tubing itself is guyed in 3 places above the Rohn tower.
This is about 60 feet high and I actually slip another 3 feet or so
of 1-7/8 into the top to gain a bit more (call it 63 feet). This works
well for me even though its a little shorter than you might prefer. It
would be a cinch to add another 10-foot Rohn section and make the gin
pole 30 feet. Then you could probably lift a 60-foot section of 2-inch
tubing and push it up to 80 feet, but I have never bothered to try (of
course the guys would get a little steep on a small lot!).
The whole thing can be put up and taken down by yourself. By the
way, I tried using telescoping sections of smaller sizes but they kept
falling down (5 times in one winter). The 2-inch system I am using now
(for 3 winters) has never come down, even in some really high winds.
But I
take it down in the summer as a concession to the neighbors!
GL.
de Randy, W7HR <hamradio@emerald.oz.net>
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