(LCA) 2013

Last week I attended 2013, my sixth LCA. It was a very well organised and enjoyable conference for me. After a few days back I miss it. I have made some good friends at LCA over the years, and catching up with them is as important for me as the conference talks. It also leads to some fascinating “hallway track” talks and lots of bright ideas for new projects.

Codec 2 and FreeDV

This year because of my Codec 2 & FreeDV work I met many people who were involved with Amateur (Ham) Radio. Mark VK5QI, and Josh VK3XJM, set up portable antennas and worked some FreeDV from various sites around the conference. Although I am an author of FreeDV I don’t have an operational HF station to test it on, so it’s an eye opener for me to see it in action.

There is a lot in common between the Open Source and Ham Radio communities, for example experimentation, communication, sharing information, open hardware and software, and the way new comers are welcomed and helped. There are also some contrasts – the average age of Hams and Linux users are several decades apart and the majority of Hams use Windows.

I can see a lot of benefit in bringing the two groups together. Linux users are fascinated with radio, and Hams can benefit from open source.

I spoke on Open Source Digital Radio (Open Office slides and OGV video and MP4 video). I had some good feedback on my explanation of Codec 2, which is based on this Octave Script which I run during the presentation. The script has buttons to allow flipping between the time domain, frequency domain, and harmonic sample views. It allows single stepping through frames to create an animated effect. Watch the video to see how it comes together.

As I described last year there is an art to presenting a deeply technical topic (like speech coding) to an audience without specific domain knowledge. I want the talk to be interesting, comprehensible, and to send each member of audience away with 3 pieces of new knowledge. So I vary each presentation, and take care to observe what works and what doesn’t.

I was also involved with a great presentation by Joel Stanley. Joel is running FreeDV on an Android phone, using a homebrew Double Sideband (DSB) receiver.

Several people approached me after Joel’s presentation and commented on how they enjoyed Joel’s simple explanation of how radio receivers work. I noticed that Linux users are naturally interested in radio, and how things work in general. So a good approach for an engaging talk at LCA is to explain how technology used on the periphery of Linux works. Demystify it, make it less of a black box for the smart, but not domain aware LCA audience.

I would like to make a special thank you to Mark, V5KQI, who operated a radio transmitter so Joel and I could demonstrate FreeDV at LCA. Mark has also been very helpful with FreeDV testing and the development of Joel’s FreeDV on Android project.

Given the strong interest in radio topics, a conversation with Tridge lead to the idea of a radio miniconf for LCA 2014. Some possible topics:

  • Get your Foundation license at
  • GNU radio tutorial
  • FreeDV
  • Build (solder) a SDR radio kit for the Ham, CB, or ISM bands.


A very good set of keynotes (available to view on line). They showed some really tough problems where progress were unfortunately being blocked by human nature. For example:

  • Bdale Garbee covered (among other things) the lack of adoption of Linux on the desktop. One of the main reasons is that companies selling Windows PCs in high volume actually get income from Windows and demo-ware. Windows is a profit centre, not a cost. So selling a PC with Linux installed actually loses money!
  • Radia Perlman spoke about networking protocols, and they are standardised. A key take away was that standards we consider to be sacred are often handed down by committees behaving like “drunken sports fans”! A funny and engaging talk.

Here is nice picture I took during the Speakers Dinner at the top of the Telstra Tower overlooking Canberra. LCA really does treat it’s speakers nicely: