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[TowerTalk] OLD Hy-Gain Rotator (long!)

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Subject: [TowerTalk] OLD Hy-Gain Rotator (long!)
Date: Fri, 13 Apr 2001 09:08:11 -0500
I have an older Hy-Gain antenna rotator that I bought used
from AES back in 1988. It's a model "RBX-5" and I was
wondering if anyone else is using one of these and has any
information on them?

I'm guessing that the unit was a commercial-type rotator
and it is very large & heavy. It's about 18" x 24" x 14"
high and weighs around 250 lbs, I'm guessing. It uses a
1/3 HP motor which is connected to a worm-type gear
box, the output of which is further reduced in speed via a
couple of sprockets connected w/ 50 pitch chain. The
output shaft is about 1-1/4" dia. solid steel and I use 50
pitch chain to connect it to the antenna mast.

The unit originally came with selsyn motors for use as a
direction-indicating system. My particular unit had a pair
of 115 volt, 400 Hz. selsyn motors. The distance from
the rotator to the control box in the shack is about 250'
and because of that, I was never able to keep the selsyns
in calibration. I tried using larger-gauge but that didn't do
any good. I was told that the reason why they wouldn't
stay in calibration was because they were 400 Hz units
and I was trying to operate them on 60 Hz power.

I had originally used the rotator to turn a KLM 40M-4
with the H.D. boom and also a Hy-Gain 204BA, which
was mounted about 8-1/2' above it on the same mast. I
put a long piece of reflective tape on the boom of the KLM
antenna in front of the boom to mast plate. I would then
get a spot light and shine it up at the antenna at night, to
see where the antennas were pointed!

This got very tiring, to say the least. At my former job, I
noticed that there were a number of NAMCO brand pro-
grammable limit switches that were used for indicating the
position of the 7th axis of robots that moved along a gantry.
These units had a 3-digit readout and I thought that maybe
I could use convert one of them for use as a really precise
system of direction indication for my big Hy-Gain rotator.

I found that these Namco units employed a gear box with
a reduction ratio of something like 29:1 to operate a small
resolver motor, which was used to provide input to the
controller box. I knew that this 29:1 ratio would be of no
use to me, as I needed a 1:1 ratio for my application. I
took the gear box apart and hooked the resolver up to
the Namco unit.

I discovered that one revolution of the resolver motor would allow the Namco
unit to count  from zero through whatever number was chosen for the range that
it was to count through. I then set the "scale" (the number range from 0 to
the highest number that would be indicated) to 359 and
the unit counted up from 0 to 359 with one full revolution
of the resolver motor!

So I went up the tower and removed the 400 Hz selsyn
motor and removed the small bevel gear from it. I then
mounted the bevel gear on the shaft of the resolver mo-
tor and bought some special 3-pair individually-shielded
wire to connect it to the controller box. It worked very
nicely. I finally had a nice digital read-out of the antenna
direction. But my new system caused another problem.

The original Hy-Gain control box used a 3-pole double
throw toggle switch for the CW - CCW movement and
I no longer needed the control box but I needed a way of
moving the antenna CW & CCW.  So I bought some
small Grayhill pushbutton switches and mounted them and
a spst toggle switch to a small piece of circuit board mater-
ial and mounted it alongside my antenna tuner. I used the
toggle switch to turn the AC power on & off to the Namco
controller box and also used it to energize a control relay
down in my basement, where the 110 VAC supply wires
went out to the rotator (I had a relay box up by the rotator with 2 - 3 pole,
double throw relays, for CW & CCW rotation).

I was wondering if anyone else is using one of these old
Hy-Gain rotators, when they were made and what the
original cost of them was? I tried to find out from Telex
Hy-Gain right after I acquired the unit in 1988 but the
person I spoke with told me that the unit was so old,
they didn't have any information on it at all. They sent me
some information on their model "3501DA" rotator, which
looks just like mine, except that they had equipped it with
a fancy control box, complete with a digital read-out and
all the solid-state electronics that went with it. The picture
of the rotator itself looked exactly the same as my unit.

Anyway, if anyone has any info on the Hy-Gain RBX-5
and would like to share it with me, I'd appreciate it!  Good
DX & 73 de Brad

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