FW: [Towertalk] AR-22 Rotor Control Box Question

Thu, 2 Jan 2003 12:56:07 -0800



> 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.
> 
> [Steve Katz]  Yes, that's true.  But with a 3L 20m beam, you probably
> don't need to adjust it in 6-12 degree increments at all, since the
> beamwidth is probably 50-60 degrees.  When using UHF satellite antennas,
> real 6-12 degree incremental adjustments can actually be necessary, so the
> "recalibration" process, which indeed takes 60 seconds, might need to be
> performed several times per hour.  -WB2WIK/6
> 
> 
> 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 ?
> 
> [Steve Katz]  Surely.  I think simply trading up to a CD-45 or equivalent,
> which can be turned even 3 degrees at a time without upsetting calibration
> (and has a quiet controller!) is a far better choice.  As for torque, you
> may be lucky or have a well-balanced load, but I've never seen the AR-22
> that I could not stop with my hands.  I can't stop a HAM-M series, at
> least not without a very large lever....  -WB2WIK/6
> 
> 
> 73/Peter SM2CEW
> 
> 
> 
> 
> 
> 
> At 15:42 2003-01-02 , you wrote:
> >Jon,
> >
> >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
> >together.
> >
> >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.
> >
> >WB2WIK/6
> >
> >"If everything seems under control, you're just not going fast enough." -
> >Mario Andretti
> >
> >> -----Original Message-----
> >> From:	Jon Ogden [SMTP:na9d@speakeasy.net]
> >> Sent:	Wednesday, January 01, 2003 4:17 PM
> >> To:	Randy Wing; towertalk@contesting.com
> >> Subject:	Re: [Towertalk] AR-22 Rotor Control Box Question
> >> 
> >> on 1/1/03 4:30 PM, Randy Wing at rwing@southwind.net 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
> >> 
> >> http://www.qsl.net/na9d
> >> 
> >> "A life lived in fear is a life half lived."
> >> 
> >> 
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