Monday, January 4, 2016

MMDVM Junior

Before I started the MMDVM, I envisaged a project where I had a small-ish box which given a few button pushes, could receive FM, D-Star, DMR, and System Fusion. This would be used in the car while commuting to work and would enable me to listen to all of the repeaters along the route. The callsigns, modes and frequencies would be in a config file, and the buttons would simply cycle through them until I found some activity. I suppose some form of scanning could have been added later.
This project morphed into the MMDVM.
My original idea was to use a Funcube Dongle Pro, a Raspberry Pi, a DV3000 AMBE board on the Pi, and a simple display also attached to the Pi.
Now that I have more experience with the MMDVM and the protocols in question, I am looking at revisiting this project. Instead of the Funcube Dongle I’d now use an AirSpy, but otherwise not much would change. Indeed it could even be used to validate my MMDVM output. I think D-Star and DMR would be simple to get working quickly, System Fusion less so. As far as I know, no one has managed to work out the mapping of the Fusion audio into the format needed for the AMBE3000R chip for all voice modes. I’m sure it will be done soon. For the full MMDVM I only need the details of the FEC for regeneration, but for this project I need to know more.
Don’t hold your breath on this. It is just an idea for now, and most of my effort is on the MMDVM.

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