Saturday, October 2, 2010

P25 Development

It's been a while since I reported on anything P25 related.

Much has been happening with the op25-dev group.

The code is still on the private sedition repo until they are ready to make an initial release and the current re-engineering of the code has been held up by a need to complete a thesis.

Apparently the plan is to re-home the repository on CGRAN or Google Code before the year end and make a public release at the same time.

If you are not familiar with the work going on, simply put; it's a Huge interoperability stride for narrowband digital radio.

An interesting suspected fork of this work is a package called the Digital Speech Decoder.

This already decodes C4FM off a sound card with a discriminator connection, and it error corrects.

If it was possible to take this a pipe it back out a sound card (without passing it to mbelib) to a transmitter in theory you could build a P25 repeater using a computer and a couple sound cards with the appropriate discriminator and varactor connections.

Jonathan Naylor, G4KLX has done this sort of thing with D-Star. And I found it most impressive.

From there the raw IMBE bit stream and headers could be IP encapsulated, sent
over the internet for the purpose of P25 repeater linking.

I don't know how many P25 groups are out there, but I'd encourage them to get the
word out to anyone with the potential programming talent.

And possibly place a bounty to help encourage this type of development.

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