For example, A1A is "morse telegraphy by on-off keying". What are the others?

  • 1
    $\begingroup$ These are ITU codes, and thus have scope much greater than the UK. $\endgroup$ Commented Mar 19, 2018 at 0:22
  • $\begingroup$ @PhilFrost-W8II I edited the title and tags to reflect your point. $\endgroup$
    – Glenn W9IQ
    Commented Mar 19, 2018 at 13:44

1 Answer 1


I found the answer in this article in the Wikipedia: types of radio emissions. From that article you can construct the different codes for different modes but there's a list of common examples:

  • A3E: AM speech communication – used for aeronautical communications
  • F3E: FM speech communication – often used for marine radio and many other VHF communications
  • 20K0 F3E: Wide FM, 20.0 kHz width, ±5 kHz deviation, still widely used for Ham Radio, NOAA weather radio, marine, and aviation users and land mobile users below 50 MHz 1
  • 11K2 F3E: Narrow FM, 11.25 kHz bandwidth, ±2.5 kHz deviation – All Part 90 Land Mobile Radio Service (LMRS) users operating above 50 MHz were required to upgrade to narrowband equipment by 2013-01-01. [2] [3] [4]
  • 6K00 F3E: Even Narrower FM, future roadmap for Land Mobile Radio Service (LMRS), already required on 700 MHz public safety band
  • J3E: SSB speech communication, used on HF bands by marine, aeronautical and amateur users
  • R3E: SSB with reduced carrier (AME) speech communication, primarily used on HF bands by the military (a.k.a. compatible sideband)

  • N0N: Continuous, unmodulated carrier, formerly common for radio direction finding (RDF) in marine and aeronautical navigation.

  • A1A: Signalling by keying the carrier directly, a.k.a. Continuous Wave (CW) or On-Off Keying (OOK), currently used in amateur radio. This is often but not necessarily Morse code.
  • A2A: Signalling by transmitting a modulated tone with a carrier, so that it can easily be heard using an ordinary AM receiver. It was formerly widely used for station identification of non-directional beacons, usually but not exclusively Morse code (an example of a modulated continuous wave, as opposed to A1A, above).
  • F1B: Frequency-shift keying (FSK) telegraphy, such as RTTY.[a]
  • F1C: High frequency Radiofax
  • F2D: Data transmission by frequency modulation of a radio frequency carrier with an audio frequency FSK subcarrier. Often called AFSK/FM.
  • J2B: Phase-shift keying such as PSK31 (BPSK31)

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