Friday, October 31, 2008

gnuais - AIS decoding on Linux

Lately I've been working on the gnuais source code, improving it so that it could be used to decode AIS and feed using Linux. My changes are in the SVN trunk (not in any released version yet). It's generally working, I just haven't done the actual "feed" part yet. But it's getting closer. The decoder isn't as good as in aismon/shipplotter - if you have DSP coding experience, your help is welcome on this project!

I've also modified some Televa 703-LYVV VHF FM receivers from the cold war era to be used as AIS receivers. "Brand new" (but a bit over 30 years old - like myself) commercial NBFM receivers in their original factory boxes, built to be installed at bomb shelters and such, but (luckily) never needed. Going to install a couple of them here in Helsinki, with directional antennas pointing southeast and southwest on the Gulf of Finland. We installed the antennas and cables during the last couple weeks, they're just waiting for the gnuais feeding code. presentation video

In June I gave a presentation on at the 30th Nordic VHF/UHF/SHF-meeting in Sappee, Finland. You can now view the presentation video on the Internet. The slides are also available in PDF format. I'm not very proud of it, with a little practice and slightly less stuttering the same amount of information could be condensed to maybe 30% of the time. Well, something to improve for the next presentation...

If you'd like me to give a presentation somewhere next summer, let me know (at least 3 months in advance, please). I'll be happy to come, if you can cover the travel expenses, and find me a bunk bed to sleep in.

Thursday, October 9, 2008

iPhone & iPod Touch support greatly enhanced

I went ahead and bought an iPod Touch (Apple's opinion) for debugging my little aprs web project. The Touch is basically an iPhone (Apple propaganda) - without the phone and the camera. It's much cheaper, but it has the same operating system, web browser, and can run the same applications, so it's fine for the purpose. I got the new second generation 16GB model (with external volume controls, speaker, etc), around 300 EUR ($400 USD). It's very pretty, and the user interface is very cool indeed.

I did a little debugging yesterday evening and tonight, and fixed a few rough corners which broke things for iPhone users. The fixes should help other mobile browsers, too. All of the pages should now render properly on the iPhone & Touch. The real-time map now loads new items nicely, and handles panning of the map. The map controls (zoom, satellite/terrain/map buttons) do not work, but that's a bug in Google's code, and they know about it already.

The changes I did in the real-time map code had an interesting side effect which benefits all users. When you pan the map on a normal web browser, targets coming in the view load a bit quicker, and the overall experience is slightly smoother than before. What a nice surprise.

The bad news is that it seems quite hard to make the real-time map work on the S60 browser, at least on my E61i (the static map works fine, of course). It simply blows up, probably runs out of memory. Maybe it could work on Nokia's new Linux-based products. Too bad I don't have one to debug with.

I'll get back to this some another day. A lot of stuff needs to be done (a nicer front page with address search, etc).

Sunday, October 5, 2008

Preferences localisation

I just moved all the strings in the options window in the string database, making it possible to translate that part of the user interface. I also changed the name of that window from Options to Preferences, to match common user interface terminology.

This weekend I've been playing with a lift we rented. Yesterday I installed snow guards on the roof - 2*6m of tube secured near the edge, designed to keep snow and ice from falling down. Makes spring-time access to our front door a bit safer.

The feed of my 40m/20m butterfly dipole is also visible in this photo.