[aprssig] APRS Dish Controller Project Solicitation?

Robert Bruninga bruninga at usna.edu
Wed Apr 30 16:21:56 EDT 2008

This is not APRS related other than we use the dish for tracking
the APRS satelites... And I know there are some good project
type engineers on the APRS SIG...

Subject: Dish Controller Project Solicitation?

We are looking for someone to design a microcontroller for our
Naval Academy 40 foot satellite dish.

The controller will be a small rack mount box with serial input
port suitible for taking AZ/EL commands from any of the popular
Tracking Programs.  The output is an analog voltage from +/- 10
volts to drive the 75 HP hydraulic system as a closed loop PID
controller.  There are a few other discrete TTL signals involved
to get the hydraulics running and to handshake with the various
interlocks.  The device will have front panel LCD readouts and
buttons.  See the web page where I am assembling ideas:


There will be two such boxes.  One at the dish and the other
almost a mile away at the control station.  One is the
controller and the other is just a remote display.  They are
connected by a serial port operating at 9600 baud with the
remote one also connected to whatever tracking program is

This dish is an X/Y dish and not AZ/EL (X goes East and West,
and Y goes North and South), but a few trig conversions can
easily manipulate between the two.  The optical shaft encoders
are 16 bit+ and operate at 9600 baud serial also but at RS422

We have been using the one I built 10 years ago that I
programmed in Qbasic and runs on a PC104 bus DOS card.  All of
the TTL level interfaces are there... But I just don't have the
time or patience any more to do this again...

So we are going to contract it out.  This will be a full blown
Government procurement with all the overhead and other baggage.
So only serious respondents should consider this.  We have not
yet written a formal spec, or procurment package.  But this is
just a heads up that we will be putting this together soon,
since this must be completed this summer.

Nothing in this email or web page in any way obligates the
government to proceed with this project.  It is just a way of
getting out the word that we are looking for a solution to
replacing our aging controller.

Bob Bruninga
US Naval Academy Satellite Lab

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