Real-time Hellschreiber decoder. Feld-Hell signals via your iPhone microphone — the oldest digital mode still in use, where your own eyes do the decoding.
Hellschreiber decoder app for iPhone. Decode Feld-Hell signals from shortwave radio using your microphone with real-time FFT, waterfall, and AFC tone tracking. The oldest digital mode still in use — no character codes, no error correction, your eye does the decoding. Essential for ham radio operators and shortwave listeners.