iPhone/iPad/iPod app to decode NAVTEX marine transmissions
In my earlier post, I introduced a new program that decodes the entire DGPS band at once, from SDR recording files. This allows you to record the band overnight, then process the recordings in the morning, to see what stations were received.
I’ve since re-written the app, with a few additions.
The big change is the ability to decode from regular WAVE audio files, if you do not have an SDR. The app can decode from multiple DGPS channels in the same WAVE file, as many as fit in the bandwidth. So if, for example, your radio is tuned to 300 kHz USB with a bandwidth of 6 kHz, then 301 to 305 kHz fit inside and will be decoded. You could of course tune to say 299.5 kHz and squeeze in another channel. Or make the bandwidth wider. Or both!
The graph window now shows a red graph at the top, which indicates the total number of messages per minute being decoded. It can be handy as a rough guide as to how well band conditions are.
I have also added support for a few other formats of SDR recordings, Studio1, ELAD, and Sdr-Radio, in addition to SdrDx / RF Space and Perseus formats. Note that I do not have all of these programs, so testing was done with files provided by others. I think it is all working correctly, but you never know.
The app is still Mac only, but the changes to this version (which is close to a complete re-write) move me closer to being able to release a Windows version. It can be downloaded here: http://www.blackcatsystems.com/software/dgps_decoding_software_sdr.html