[amsat-bb] Re: video: stand-alone tracking and tuning with Arduino

Alexandru Csete alexc at phys.au.dk
Tue Dec 1 08:20:29 PST 2009

Quoting Bruce Robertson <ve9qrp at gmail.com>:
> Gang:
> The following one-minute video shows my breadboarded Arduino
> (ATMega328) tracking two satellites and tuning an FT-817 in response.
> It also shows the chip periodically announcing the location of the
> bird in CW, and, as a bonus, you'll see AO-51 being received with a
> simple dipole directly connected to a low-noise preamp.
> http://www.youtube.com/watch?v=XgNcCGXeRyw
> This is an application of the Arduino FT-817, Plan 13, CW and Tle
> EEPROM storage libraries available at:
> http://code.google.com/p/qrptracker/

Hi Bruce,

Very nice work, I enjoy following your progress with this project.

> ...
> Right now, however, the code only tunes the downlink, and I have to
> spelunk through the code for Instanttune to see how to deal with the
> FT-817 on transmit :-)

You should be aware that the FT-817 frequency can not be controlled  
via CAT during transmission. There are different workarounds  
implemented in different desktop applications, but AFAIK none of them  
enable active tuning while PTT is on.

On the other hand, you can change the frequency using the dial. The  
dial is an optical encoder so it might be possible to hack it that  
way. In my frustration I have actually considered this.


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