Feld Hell Decoder

I was tuning around this morning, and caught WA9HCZ, Jerome in Wisconsin, sending Hellschrieber on 10.139Mhz (in the 30m band). It was actually the first “in the wild” Hellschrieber that I had heard, so I quickly fired up cocoaModem to decode it, and also recorded some of the audio in Audacity so I could experiment with decoding it later. A bit more work, and I managed to generate this image using some software of my own devising:

Hellschrieber QSO, decoded with my own software…

Addendum: Tighter filtering around the center frequency results in a somewhat cleaner and possibly more legible decode.


With tighter bandpass filtering, it looks a bit better.