Tag Archives: rpi

Digital Hotspot

I started collecting stuff to put together a digital radio tinkering platform a while ago. MMDVM is a digital modem impelemntation by Jonathan Naylor G4KLX that runs on the Arduino Due and other 32-bit ARM platforms, not only does it do DMR, it also does Icom’s DSTAR and Yaesu’s C4FM. I’ve been nagged by some users of GB3NM to put a C4FM facility on there so maybe this could be the start of that implementation, who knows?…

Hucknall Rolls-Royce ARC hosted a talk by Jonathan on Friday 2nd June which I attended – well worth the trip, excellent presentation! So now I feel a bit more confident about how it all fits together maybe I can make some progress.

I ordered a ZUM interface board from Bruce VE2GZI via the MMDVM website back in March, and apart from plugging it into the board no progress until today. After chatting with Dominic G7NPW he suggested it was possible to build a hotspot with only one radio so let’s see what I can get working so far (no radio at this point).

At this point I don’t have a decent radio to set up the RF side, athough I try getting it to work with Yaesu radios that have a 9600baud data connection (FT-817ND, FT-8900 might work).

Well so far I’ve managed to get it connected to the Brandmeister network. Dominic recommended a Rasperry Pi image that has a pre-configured hotspot, Pi-Star. I’ll investigate this just as soon as I find where I left my Pi Zero and spare SD cards…

Direwolf Pi

Direwolf Screenshot

Direwolf Screenshot

I am now evaluating Direwolf for HF packet reception on 10.1476MHz. It’s running on a Rasperry Pi 2 with the cheapo Cmedia sound card and the performance looks extremely good. I just need to figure out why I’m getting broken pipe errors though.

I haven’t yet decided whether to run it as stand-alone igate or use it as a TNC in conjunction with Xastir as it provides either AGWPE or KISS type interfaces to external programs.

Update 13th May – I reduced the number of parallel modems from 7 to 3 and this seems to have cured the broken pipe errors. I’m now gating received traffic to APRS-IS using the built-in client. Traffic reported can be seen on aprs.link.