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Re: Homebrew Rotator Question



Paul,

Having tried the "pot with weighted arm" technique shown in the Handbook, 
I'd recommend a bit of a modification.  Attach the arm to something fixed, 
or somehow keep it from swinging freely.  There are two problems with the 
Handbook's design.  First, the friction in the pot gives the arm some 
histerisis, so the pointing accuracy suffers.  Also, wind can play an 
unwanted role in moving the arm.  Go for something where the the pot has a 
solid mount.

Or, use the clickity-clickity interface on the Alliance rotor as it was 
intended, by building a controller that simply counts the contact closures 
as the motor moves.  You get a 10 degree accuracy; not real great, but it 
works.  If you're interested in doing this, I have some design notes at:  
http://home.jps.net/~gregd/hamsite.htm

Good luck,

Greg  KO6TH




----Original Message Follows----
From: "George Henry" <ka3hsw@earthlink.net>
To: "amsat bb" <amsat-bb@amsat.org>
Subject: Re: [amsat-bb] Homebrew Rotator Question
Date: Sat, 11 Mar 2006 20:27:38 -0600

Check whether your local library has "The Satellite Experimenter's 
Handbook"...  if not, they can probably get it for you thru interlibrary 
loan.  There was an article in there detailing a couple of techniques for 
adding position pots to that type of rotor.  The simplest is the bracket and 
weighted arm that you mentioned.  Another possibility would be belt-driven, 
off the crossboom.  Adding something to the gear train internally would be 
much more complex...

George, KA3HSW


----- Original Message ----- From: "Paul Proefrock" <paul@proefrock.net>
To: <amsat-bb@amsat.org>
Sent: Saturday, March 11, 2006 4:44 PM
Subject: [amsat-bb] Homebrew Rotator Question


>I have been looking for any article or information on adding potentiometer
>control to an Alliance U-100 or U-110 type rotator - the type that can be
>configured on its side and allow a cross-boom to go thru it.
>
>
>
>Does anyone have any information on this? I have just about burnt up Google
>and can only find manual type systems, not any potentiometer / servo type
>setups
>
>
>
>Some have added an external Pot with a weighted arm. How about an internal
>modification to add a pot to the gear train?
>
>
>
>Thanks
>
>
>
>Paul P
>
>K0PRP
>----
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----
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