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

Lizeth Norman normanlizeth at gmail.com
Sat Feb 23 20:25:30 PST 2013

It's an interesting question as to how much antenna that can be hung
on those gearhead motors. At 20 bux plus shipping, that's reasonable
for a hobbist budget. need two, the cable and metal (cool how the
worst of the metal work is done for you with KA6PUW's design.) Need to
do a BOM but should work out less than 100$ Probably kit it for less,
particularly the metal bits. Cheaper to buy by the 100's of feet, of

The reference to SolidWorks is that the math needs to be worked out
regarding the shaft torque. Haven't been that far yet.

A thought is to have three build scales. One portable. One for
home/regular sized arrays, and a monster, no expenses spared version.
This is pretty easily doable with the electronics package you suggest,
just a different ,motor drive block, assuming DC motors and some sort
of feedback loop.

Curious to know, but the budding ECE in me wants to know what
development environment / microcontroller product families are in
consideration. The processors keep getting smaller and smaller. What
about a rasberry pi with a display in HD??? Amazing..

Norm n3ykf

On Sat, Feb 23, 2013 at 11:03 PM, Samudra Haque <samudra.haque at gmail.com> wrote:
> hi, thanks for addressing this question. And I invite others to participate,
> or get in touch with me for a phone conversation, and discuss simple steps
> that can be taken IMHO within 50-100 USD. I suggest we adopt AMSAT friendly
> tips:
> http://www.amsat.org/amsat-new/tools/downloads/iROTOR.pdf (will need
> additional interface to PC, any kind)
> (cool idea, but only as concept)
> http://www.amsat.org/amsat-new/echo/Az_El_Pos.pdf
> http://dgg.gotdns.com/doc/XOX_rotor.pdf (Semi professional..)
> http://ka6puw.tripod.com/azimuth1.html <--- what do you think of this style?
> Looks simple enough.
> But I have only done a simple google search here. Any other projects worth
> investigating? Focus on the "mount" only now.
> -samudra
> On Sat, Feb 23, 2013 at 10:41 PM, Lizeth Norman <normanlizeth at gmail.com>
> wrote:
>> Samudra,
>> This is a good question for a first year engineering student like
>> myself: How does one bring home the best bang for the buck out of an
>> engineering dollar?
>> Feel free to ask around. A few on the list have driven unusual devices
>> to get antennas moved.
>> How does a project get into the hands of people who will actually do
>> it? A one off I can do for you in my basement. Probably with parts
>> from radio shack, a grinder and a few hand tools.. A reproducible
>> project 10 years from now? Hardly likely.
>> I submit to you that irrespective of the metalwork this is a simple
>> project as you propose, however it must be reproducible. With a
>> student copy of SolidWorks, a circular saw, drill and the Arduino IDE
>> it could be prototyped by two people in a weekend. Refining it so that
>> a relatively new ham with a smidgin of technical ability could do it
>> might take a little longer. These days with the internet and cad, the
>> real issue is the tooling. How do you design/layout such that it can
>> be done with snips/file/saw/fill in the blunt instrument here..
>> 73 es have fun..
>> Norm n3ykf
>> On Sat, Feb 23, 2013 at 10:19 PM, Samudra Haque <samudra.haque at gmail.com>
>> wrote:
>> > I hope it is evident, I am not focusing on the
>> > controller/microcontroller/computer interface/az-el controller/etc. The
>> > real
>> > issue is how cheaply can an antenna be mounted on a kingpost somewhere
>> > on a
>> > surface, with a view towards the sky, and how conveniently can that
>> > mount be
>> > motorized, with a sensor to give feedback to the ground station.
>> > electronics, seem to be, (apologises to EE friends) a dime a dozen,
>> > cheaper
>> > if made in hundreds, but the key drawback of any design is the
>> > mechanical
>> > and electromechanical (can we use, mechatronics) system that serves as
>> > the
>> > actuators. I am not referring to a hand held antenna assembly, but
>> > rather
>> > something that we can all use in cold/hot weather and that can be put
>> > together by one / two persons on an average post.
>> >
>> > Comments welcome, I think the future holds bright for amsats and edu
>> > based
>> > cubesats.
>> >
>> >
>> > -samudra
>> >
>> >
>> > On Sat, Feb 23, 2013 at 9:50 PM, Lizeth Norman <normanlizeth at gmail.com>
>> > wrote:
>> >>
>> >> Gus and the group:
>> >> Lots of birds going up in the next year. Success rate not 100% as it's
>> >> rocket science oftentimes on a budget. Hopefully we'll get a few out
>> >> of it.
>> >> The Arduino IDE install supports PPM. The nice thing about that
>> >> platform is that configuration is doable for just about all forms of
>> >> hardware that you might drive with it and scaling can be done in
>> >> software for the various different bits of kit.
>> >>
>> >> I am sure that with the appropriate development environment and having
>> >> the hardware on hand IN a well equipped lab, it should be a weekend
>> >> project to get running.
>> >>
>> >> The hard bit in my opinion is how to mount the antennas to the az/el
>> >> clockwork. Will require a little woodwork/metalwork to finish.
>> >>
>> >> Everyone who does this will have a problem with some phase of it.
>> >> Needs to be simple and repeatable.
>> >>
>> >> Norm n3ykf
>> >> _______________________________________________
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>> >> author.
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>> >

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