I would like to solicit advice from the group.
I have a 124' Rohn 55 tower. Temporarily, for the antenna mast, I
have a Ham IV in place, ONLY AS A PLACEHOLDER, and an additional
steel bracket locking down the mast and prohibiting rotation. The
rotor shelf is at 115 feet (down 9' from the top) and the guy bracket
is at the same location, to transfer most rotational torque directly
to the guy wires. I opted to NOT use a thrust bearing, but instead
have a 1' thick reinforced nylon bushing bolted to the top plate. I
have 2" diam, 1/4 ' wall Chromolly mast that is 24', which gives me
13' above the top of the tower. There is also a 6 element 6 meter
yagi at the top of this mast. I have a 44' boom, six element OWA for
20 meters just above the top plate. The 20 meter antenna is about 11
sq ft of windload, and the 6 meter is about 1.8 sq ft.
My plans were to free up an RD-1800 (made by CATS/Rotor Doctor),
which is currently turning a KT36XA and a 2 el forty on another
tower, and use this to turn the antenna on the mast.
This weekend, I picked up an original Orion 2300 (AC), with
controller. The unit was just rebuilt, cleaned, greased and limit
switched checked. The control box was also checked out, and all
appears to work fine, including the speed control. Apparently this
model still had the pot, rather than the pulse counter, and on the
bench, reads exactly where the rotor is pointing. So far, the only
noticeable shortcoming is there is no automatic speed ramp up/down. I
could adjust the speed as I turn it, or simply run the unit slower.
Yes, there is a question coming. The Orion series seems to be
considered one of the strongest "conventional" rotors on the market.
Is there any reason I should NOT use the old model Orion for turning
the 13 sq ft of aluminum I have at 124' high? This will be the top
antenna in a three stack, so I won't be turning it "every" time I
need a different direction - I can turn the middle OWA on a Tic-Ring,
and actually often point them different directions, anyway, for
diversity and quick direction changes.
If I do use the Orion, would it be wise (or even possible) to
eventually change the AC motor out for the newer DC version (granted
I'd have to change the control box if I did this)?
Any guidance on the pros and cons of this older Orion would be appreciated.
73,
Mark, K5ER
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