>I've just completed the transit work for a Rohn 55 rotating tower. I want
>to start pouring concrete for the base and anchors very soon. I have a
>couple of unique situations inherent to my property and wonder if anyone
>could offer me some advice. i.e. has anyone "Been there, done that."?
>
Ralph:
I have a similar situation. I am rotating 140 feet of 55G. I used
the 5 foot concrete base section with 3 feet in concrete. The RTS
bearing and rotater sits a few feet above the ground and I have rings
at 40, 80 and 120 feet. Since I'm on the side of a hill, the lower
guys slope away and the upper one is rather short, but at the correct
angle.
I went with 3x3x6ft (2yds) holes for the guy anchors, with
rebar cages holding a heavy steel pipe that we welded flat steel plate
"loops" to for the guys. These pipes are about 8" dia with 1/2" wall
and are filled with concrete. They stick about four feet out of the
ground. I use steel cable up to about 15-25 feet, then go to Philly.
The steel is to minimize fire and vandalism potential. Unfortunately,
I put the turnbuckles at the joint between the steel and the Philly,
also to avoid vandalism. But its real hard to get to those turnbuckles,
especially on the side of the hill. Wish I had put them at the tower
(don't know of anyone who has done this however) or at the ground
with some kind of locking device. Our property isn't fenced and
there are alot of kids walking through.
The tower has lots of aluminum and has been very reliable since we installed
it in October 1989. In fact, we had just finished putting it up
and were in the process of bringing up the 40 meter beam when the
Loma Prieta earthquake hit. I was at the top of the tower.
The only change I'm making now (although I've made lots of antenna
changes over the years) is the rotater. I bought the tower with an
old Telrex rotator that had been converted for this use. I'm waiting
for my M2 2800P to arrive which will give me presets and programmable
ramp up/ramp down. Without that, I've been turning it at the recommended
1/2 RPM and it TAKES FOREVER!
Hope this helps.
73, Howard WZ6Z
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