Q code

The Q code is a standardised collection of three-letter message encodings, all starting with the letter "Q", initially developed for commercial radiotelegraph communication, and later adopted by other radio services, especially amateur radio. Although Q codes were created when radio used Morse code exclusively, they continued to be employed after the introduction of voice transmissions. To avoid confusion, transmitter call signs have often been limited to restrict ones starting with "Q" or having an embedded three-letter Q sequence. The codes in the range QAA-QNZ are reserved for aeronautical use; QOA-QOZ for maritime use, and QRA-QUZ for all services.

Early developments

The original Q codes were created, "circa" 1909, by the British government as a "list of abbreviations... prepared for the use of British ships and coast stations licensed by the Postmaster-General". The Q codes facilitated communication between maritime radio operators speaking different languages, so they were soon adopted internationally. A total of forty-five Q codes appeared in the "List of Abbreviations to be used in Radio Communications", which was included in the Service Regulations affixed to the Third International Radiotelegraph Convention. (This Convention, which met in London, was signed on July 5, 1912, and became effective July 1, 1913.)

The following table reviews a sample of the all-services Q codes adopted by the 1912 Convention:

See also

* ACP-131

External links

* [http://www.telegraph-office.com/pages/q-signals-1909.html Handbook for Wireless Telegraph Operators] , October, 1909.
* [http://www.earlyradiohistory.us/1914reg.htm Radio Laws and Regulations of the United States: Edition July 27, 1914] . (Includes the 1912 London Radiotelegraphic Convention)
* [http://www.arrl.org/files/bbs/general/q-sigs ARRL amateur radio Q signals]
* [http://life.itu.ch/radioclub/rr/m1172.htm ITU Q code table for the maritime mobile service]
* [http://www.kloth.net/radio/qcodes.php List of Q codes]