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Re: "Space Scanner" - Automatic Satellite TV Tracking System



Several hams have played with these for various purposes.  These used to be sold at Allelectronics in Los Angeles where I bought mine.  The individual motors were sold at www.allelectronics.com but I don't see them in their current web site.  The complete actuator assembly is about the size and weight of a bowling ball and is designed to be used on mobile platforms like boats and RVs, so they see a lot more motion than simply changing from one sat to another.  If I remember correctly, the motors ran on 12V and had a 24V brake.  The motors can run on much less voltage if you want them to run slowly.
Tony, KC6QHP has used one for mounting his 10 GHz antenna, formerly a standard Ku band TV dish.  He had planned to control it via a homebrew controller, but I do not know if he completed the project.  Photo of the mounted antenna used in the 2002 Microwave contest is at http://www.ham-radio.com/sbms/02_testpics/02_test_qyr/qhp_1.jpg  This set-up simply had switches to actuate up/down and left/right.
More recently N6CA and others have been playing with these.  He has some notes at http://www.ham-radio.com/n6ca/microwave/trkr/trkr.html.  The motors should work for a small satellite array, but the control will require some tinkering.  I don't know if any sensing of motor position is included in the stock motor set-up, but I don't think so.  N6CA's notes show a potentiometer, but I think that is a modification.  I have been unable to get mine open due to some very stubborn screws.  The motors and gears look to be fairly strong with steel gears etc.  I wouldn't try to mount a big array on one, but I'm sure it could handle a small array for LEO V/U, U/S or L/S especially if BBQ dishes were used to minimize wind loading.
73,
John, KJ6HZ
______________________________________________________-
Hi Mike:

Mike, K4HN wrote:

> I've seen these at the Orlando hamfest the last two years. They are setup
to
> pick out the DISH and DirecTV type geosync sats.  You tell it which one
and
> it points the dish to it.  I looked at the manual in Orlando and couldn't
> see an easy way to make it track a non geosync sat.  It looked to me like
> its logic was set up to track the equatorial geosyncs only".

I read the info on the manufacturer's website.  Yes, it looks like it is
designed to only track the equatorial geosyncs only.  I do not expect to be
able to automatically track any non-equatorial geosync satellites.

I would like to determine if it is reasonable to modify the unit and use it
as an Az/El positioner for a DSS dish connected to a PC controlled antenna
rotor interface.  Since the motors are 12 VDC with 24 VDC brakes, this seems
very reasonable.

However, the motors and gear assemblies would experience a lot more use in
tracking a LEO or HEO satellite as opposed to occasionally changing position
to a different Geo-sync satellite.  I was hoping to find out if anyone had
tried to use one of these units and if the motors and gear assemblies are
heavy enough for Amateur satellite tracking.

73,

Woody
KJ4SO
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