Morse Decoder

Morse Decoder takes audio input from the microphone or audio input on your Mac, decodes Morse Code tones, and displays the results in text form. It includes both automatic decoding of longer clean signals, as well as several manual controls to allow the decoding of more difficult signals in QRM. Decoding parameters that can be manually configured include the audio frequency of an optional narrow-band DSP filter, the WPM dot/dash speed used for detecting characters, the threshold level above background noise, and whether Farnsworth timing is to be used for detecting spaces between individual characters.

If the audio filter is enabled, the filter can be set for frequencies in the range of 400 to 1400 Hz. Click the spectrogram to set the audio filter to the desired frequency of signal. Checkboxes can be used to toggle squelch, AGC, filter and WPM modes.

The Morse code WPM (words per minute) detection speed is automatically adaptive from about 8 to 40 WPM, and can be locked to the current estimated WPM dot speed (WPM lock icon locked). There is a High Speed WPM Mode which may work for code speeds in the range of 30 to 80 WPM, and which also supports higher frequency dot-dash tones.

It may take several initial and immediately preceding characters containing both dots and dashes before the WPM speed estimation starts to get close to the actual WPM. Background sounds and signal fading can interfere with detection and decoding. The quality of decode depends on the signal level, signal to noise ratio, stability of the frequency and WPM speed, keying "fist" quality, and whether you have configured the app properly for the signal.