Foundations of Amateur Radio

The thing I think I love most about the hobby of amateur radio is the challenges it represents, not in terms of life or emotional ones, though I will admit that there's some of those .. in no small part due to the variety and complexity associated with being human and a member of the community, more in terms of figuring out how stuff works and then how much stuff there is.

I was first licensed in 2010 and since then I've attempted to document the experience of being an amateur and discovering just what that might mean.

This week has been interesting, if not quite as productive as I was hoping for. I spent a full day working on SoapyAudio, you might recall, it's one of the potential puzzle pieces in my Bald Yak project.

I can report that it compiles fine on a Raspberry Pi 2, and when I get a moment I suspect that it will also work just fine on a Pi Zero.

When I got to the point of packaging it all up, I spent hours trying to get my head around the Debian packaging system. For reasons I don't understand, nobody appears to have written anything that monitors the standard 'make install' step, save for one project called 'checkinstall' which has some serious bugs, like overwriting the system password file, and is not recommended.

While in the middle of that adventure I discovered that SoapySDR and associated modules, utilities and support tools are already packaged in Debian. I'll confess that I emulated a stunned mullet when I noticed that.

While this might mean that I essentially spent three days shaving a Yak for apparently no good reason, it did allow me to discover that SoapyAudio is currently receive only, but adding transmit doesn't look like an unsolvable problem.

I still don't know why I went down the compilation steps but it allowed me to peruse the source-code which helped discover how some of this hangs together and I'll hasten to add that my understanding is currently incomplete at best, but that's par for the course. After discovering the existing packaging I installed 'soapyremote-server' on the Pi and it worked out of the box .. something which I'm happy to say is a regular occurrence with Debian packages, perhaps this is why packaging is so complex, another thing to investigate as time permits.

I then added an external USB sound card with the audio going into the rear DATA socket of my FT-857d, and together with the CT-62 compatible USB CAT cable, that's Computer Assisted Tuning, allowing remote control of the radio, the Pi was ready to be the network interface to my copy of GNU Radio.

Well, not quite.

There's some secret incantations that I have still to divine, but thanks to random forum posts with hints at how to format the command string required, I'm making progress. GNU Radio can see the Soapy Server, has passed the checks to control the radio, which happens behind the scenes thanks to Hamlib, but stumbles on the audio card side of things. If it weren't for other life affirming activities in my diary, I would be reporting success, but I can tell you that I can taste it.

Now, why does this make me excited?

Well, it means that I can now use my FT-857d across the room, technically across the Internet even, to receive and process RF within GNU Radio. You might recall that this is one of the stated aims of this whole endeavour.

In terms of "50 things to do with an SDR", this one will end up in the "Listen to conversations on the 2-meter amateur radio band" pile. While it's not particularly exciting to listen to the local repeater across the room, something which I can do by turning up the volume or getting a long headphone lead, it represents a small milestone in the pursuit of my Bald Yak project which aims to create a modular, bidirectional and distributed signal processing and control system that leverages GNU Radio. It's called Bald Yak because by the time I'm done, the Yak is likely well and truly shaved.

So .. micron by micron I'm getting closer.

Also, "like a stunned mullet" means to be dazed and uncomprehending, feel free to use it in public.

I'm Onno VK6FLAB