Hem SAQ Forum SAQ Transmissions Audio decoding Svar till: Audio decoding

Rabbe Fogelholm

It is sad to hear that the Old Lady is not fit to sing out over the oceans this summer. Let’s hope for a steady and fast recovery.

Analyzing old recordings can be done anytime though! There is now a version 3.0.0 of the gerke-decoder program, where adaptivity against frequency drift and fading has been added.

The program expects input in .wav format and prints out the Morse code message as cleartext. Information about audio frequency, words-per-minute rating, timing of inter-character spaces, etc can be printed too. The signal can be displayed graphically for studying dashes and dots shapes, garbled characters and such.

Recordings in .mp3 format work well also, after converting to .wav format with some tool like Audacity.

By default the program listens for audio in the comfortable audible range, but a different frequency range can be specified – even up at 17200 Hz if a recording of the raw antenna signal has been made.

Find the program here: https://github.com/fowlay/gerke-decoder

Building from source is straightforward on Linux. If you don’t have a Linux box you may instead use this pre-built executable jar: https://privat.bahnhof.se/wb748077/radio/3.0.0/gerke-decoder.jar

Comments and ideas are always welcome.


Be the first to know about upcoming SAQ transmissions by subscribing to our newsletter.

No, thanks!