[amsat-bb] Re: inquiry about homebrew az-el systems

[Samudra Haque]

Thank you Greg and Art for your suggestions. I'm interested to pursue the
standard mechanism (AZ-EL rotors) but also want to inquire about any recent
 robotics work in this area ? A 2-link robot with a rotary joint
manipulator that would point an antenna , could be a candidate solution -
with no problems for normal/flip mode. I have some minor experience to use
in this area - any collaboration possibilities ?


On Sat, Feb 23, 2013 at 7:58 PM, Greg D <ko6th.greg at gmail.com> wrote:

> Hi Samudra,
>
> See: http://home.wavecable.com/~**ko6th <http://home.wavecable.com/~ko6th>Near the top of the page, on the left, are links to the design document and
> code source for what I created. It's not a kit, but rather a discusson of
> the various pieces needed to make such a controller, which you can adapt as
> needed to whatever hardware you can get your hands on. The Alliance U-110
> makes for a great Elevation rotor, and there are many Az rotors that can be
> had for very low cost. Alternatively, as long as you can supply a contact
> closure every 6-10 degrees of rotation, this system can be adapted to a
> variety of mechanical contraptions. Let the students and faculty get
> creative!
>
> Good luck,
>
> Greg KO6TH
>
>
> Samudra Haque wrote:
>
>> Hi, about two years ago, I started a design for a robotics class project
>> of
>> a AZ-EL rotator controller system, and a hardware package for the
>> mechanism
>> for rotating an antenna in any direction subject to mechanical stops. The
>> system would have been able to handle regular and flip modes. I didn't do
>> anything more than calculations, and moved on to building a classroom
>> instructional robot then.
>>
>> Lately, as I am setting up (K3GWU, the George Washington University
>> Amateur
>> Radio Club and Research Station) I find that the price of az-el systems
>> such as G5500 + Yaesu AZ-EL rotors are expensive, and are not typically
>> available on an affordable basis on Ebay or eham.net etc. Well, of
>> course,
>> expensive is a relative term, for a student hobby organization, it's a
>> lot,
>> and I guess for small ham operators it is also moderately expensive.
>>
>> This may be a frequently asked topic: does any one have experienced with
>> (tested) kit designs for AZ-EL rotors that can be made with parts from
>>   current suppliers ? I know there are a number of controller designs,
>> but I
>> am interested to know if there are any options for suppliers of the
>> required gears/motors etc.
>>
>> I have located several large AC motors / DC motors at my university
>> mechanical engineering workshop, but they are not all guaranteed the same
>> specs. I now realize if I do embark on a actual design process with my
>> model/simulation/hardware, it would be nice to build several of these all
>> at once to share the development cost over the production run, and ensure
>> those who want a cheap AZ-EL system can get one. Otherwise the production
>> cost of one heavy duty system is going to be quite high.
>>
>> I hope some of you may have suggestions for me, both (+) and (-) or
>> perhaps
>> (~) in nature. I thought amsat / amateur radio folks have a common need to
>> encourage homebrew activity to keep their brain cells in working
>> condition?
>>
>> I'm opening this question up to the national US audience, and welcome any
>> discussion on the challenges of making the ever-so-important
>> azimuth-elevation rotor. I've studied some of the alternatives: Alliance
>> U100 and Yaesu G-5500. I think we can do better in 2013. But ideally, to
>> allow the wide adoption of AMSAT ground stations, what price point would
>> the system have to be to make it worth building ?
>>
>> 73 de N3RDX
>> George Washington University
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>