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How to Identify the Sounds of Digital Ham Radio Communications

While most associate the ham radio operator with the stereotype of a person with headphones taking into a microphone or rapidly tapping away in Morse code, there are many other ways they can communicate. One of these ways is through digital communications, and with an understanding of their different sounds, one can identify what type of transmission it is without even needing to decode it.

Things You'll Need

Shortwave or Ham Radio receiver

Instructions

- 1
  Listen for a rhythmic pattern of what sounds like a series of "dits" and "dahs." If you hear this, the digital transmission is called Morse code, or in ham radio terms 'CW.' Each group of dits and dahs represents a letter, and each group of letters is a word. A trained ham radio operator will be able to decipher this code by ear.
- 2
  Listen for a high pitched, continuous warbling tone. It is called radio-teletype, commonly abbreviated as RTTY. Unlike Morse code, RTTY necessitates a computer program to decode the transmissions.
- 3
  Discern whether the sound has a mid-ranged hum to it with a higher tone which seems to fade in and out. This is known as phased shift keying, or PSK-31. If it has a warbling sound with longer, low tonal periods to it, then it is likely multi-frequency shift keying, of MFSK. A computer program is also required to decode these text transmissions.
- 4
  Listen for a generally high-toned sound with high-pitched clicks. This is the sound of slow-scan television, or SSTV. In this case, images are being transferred between ham radio operators using specialized computer software.
- 5
  Listen for what sounds like a connecting dialup modem. This is the sound of packet, which ham radio operators used to send data files from one station to another.

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