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[Towertalk] AR-22 Rotor Control Box Question

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Subject: [Towertalk] AR-22 Rotor Control Box Question
From: (Peter Sundberg)
Date: Thu, 02 Jan 2003 21:01:04 +0000
I would not call the AR22 indication system a servo control system. It is a
solenoid stepper system that is actuated by a switch in the rotor unit.
Very simple. The good thing is that the readout is recalibrated in about 60
seconds, the time it takes to rotate back to one of the end stops.

As for the torque, I find it pretty good for what it is. I have had a 3 el
monobander for 20m on one for years without a problem, no thrust bearing. 

The annoying thing is the loud CLICK the control unit makes, it can wake a
whole household up in the middle of the night.

It would be pretty easy to build a new silent control unit that catches the
pulse and displays the direction in degrees, counting + or - 6 degrees on
every pulse from the rotor.. but that is another story. Isn't that what the
M2 rotor control unit is doing, pulse counting ?

73/Peter SM2CEW

At 15:42 2003-01-02 , you wrote:
>It does sound as though the rotor is binding in one direction.  Make sure
>the load above the rotor is very balanced; any amount of imbalance when an
>AR-22 is used without a thrust bearing will make it practically stop -- it
>doesn't have nearly the torque of a CD-45 or HAM-M type.
>Also, the AR-22 servo control system does not work well if the rotor is used
>for small incremental changes in direction.  Remember, these were
>inexpensive rotors (I bought several brand new in 1966-67 for $39/each,
>complete with the control box) intended to turn TV antennas that were not
>highly directional; it was normal to crank the rotor 45 degrees or more at a
>time, to favor TV signals from another city.  It would have been extremely
>rare for anyone to need to turn their TV antenna only two or three "clicks"
>(12-18 degrees) at a time, as from practically nowhere are cities this close
>If you need to turn the rotor only 12 degrees (two "clicks" worth of
>rotation), it is best to crank it ten clicks forward, then eight clicks
>back.  That accomplishes the 12 degrees of desired rotation without
>stressing the sytem beyond what it can handle.
>It was very common, even with brand new AR-22's, that if you used the rotor
>to make 1-2-3 "click" adjustments, after doing so the indicator would be
>quite far off.  That was normal, and I don't recall any known fix for this
>-- it's inherant in the design.
>The AR-22 is not the greatest choice for highly directional antennas, no
>matter how lightweight they may be.
>"If everything seems under control, you're just not going fast enough." -
>Mario Andretti
>> -----Original Message-----
>> From:        Jon Ogden []
>> Sent:        Wednesday, January 01, 2003 4:17 PM
>> To:  Randy Wing;
>> Subject:     Re: [Towertalk] AR-22 Rotor Control Box Question
>> on 1/1/03 4:30 PM, Randy Wing at wrote:
>> > Jon,
>> > 
>> > I oversimplified.  What I meant to add to this was that there is an
>> > adjustment on the CDE for correcting for incorrect amounts of slew.
>> > 
>> No, I've not done that.  I have no instruction manual.  How do you do
>> that?
>> Also, the rotor seems to turn faster in one direction (clockwise) than in
>> the other (CCW).  The "clicks" come a lot slower.  Is it possible that I
>> am
>> binding a little bit in one direction?
>> Thanks,
>> Jon
>> -------------------------------------
>> Jon Ogden
>> NA9D (ex: KE9NA)
>> Citizen of the People's Democratic Republik of Illinois
>> Life Member: ARRL, NRA
>> Member:  AMSAT, DXCC
>> "A life lived in fear is a life half lived."
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