M17 project

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SP5WWP

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Hello!

I'd like to introduce you to my digital radio project. I have started it about a year ago. The aim is to create a fully functional, truly open-source and open-hardware system for digital radio communication. Something like DMR, but with open hardware. I have already built a working radio prototype (called TR-9). At the moment I'm working on a repeater. I have made a one way QSO with it. The voice packets were transmitted on the RX freq from a TR-9 radio to my repeater, then were sent via UDP to a remote location and decoded there. Here are some photos:

M17_repeater.jpegTR-9_v1.2.jpeg

There is a blog about M17 here. GitHub repos are here. I know the description of this project is very tentative, so please feel free to ask me about it.
 

RFI-EMI-GUY

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Since you are designing from ground up, how difficult would it be to implement TDMA in the sense that a repeater could receive one portable on one slot and re transmit to others on another timeslot. This would permit single frequency repeater saving the complexity of a duplexer. Also if you can provide an IP interface you can link many repeaters together.
 

SP5WWP

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Your TDMA concept wouldn't actually reduce complexity, as it would require at least 1 RF switch.

The software on Raspberry already sends packets via UDP. All there is to do, is to transmit them too (upon receive).
 

RFI-EMI-GUY

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Your TDMA concept wouldn't actually reduce complexity, as it would require at least 1 RF switch.

The software on Raspberry already sends packets via UDP. All there is to do, is to transmit them too (upon receive).
True, but it is surprising how expensive and difficult FDMA duplex can be for some to implement properly. There are pros and cons to both schemes, but for a small repeater the TDD approach is simpler. Having both capabilities would be great.
 

SP5WWP

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Do you know any place where I could tell people about M17? QRZ forums, maybe? I guess a short demonstration video and a presentation would help a lot.
 

kb9mwr

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Personally I find a lot of good discussion on reddit these days.

They have an area for developers here:
 
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