The Maritime Mobile Service Q Codes are art of a larger set of
Q Codes
The Q-code is a standardised collection of three-letter codes that each start with the letter "Q". It is an operating signal initially developed for commercial radiotelegraph communication and later adopted by other radio services, especially ...
designated by the
ITU-R
The ITU Radiocommunication Sector (ITU-R) is one of the three sectors (divisions or units) of the International Telecommunication Union (ITU) and is responsible for radio communications.
Its role is to manage the international radio-frequency sp ...
. The QOA–QQZ code range is reserved for the
Maritime Mobile Service A maritime mobile service (also MMS or maritime mobile radiocommunication service) is a mobile service between coast stations and ship stations, or between ship stations, or between associated on-board communication stations. The service may also ...
.
This assignment is specified in RECOMMENDATION ITU-R M.1172.
Q signals are no longer substantially used in the maritime service.
Morse code
Morse code is a method used in telecommunication to encode text characters as standardized sequences of two different signal durations, called ''dots'' and ''dashes'', or ''dits'' and ''dahs''. Morse code is named after Samuel Morse, one of ...
is now very rarely used for maritime communications, but in isolated maritime regions like
Antarctica
Antarctica () is Earth's southernmost and least-populated continent. Situated almost entirely south of the Antarctic Circle and surrounded by the Southern Ocean, it contains the geographic South Pole. Antarctica is the fifth-largest contine ...
and the
South Pacific
The Pacific Ocean is the largest and deepest of Earth's five oceanic divisions. It extends from the Arctic Ocean in the north to the Southern Ocean (or, depending on definition, to Antarctica) in the south, and is bounded by the continen ...
the use of Q Codes continues. Q Codes still work when HF voice circuits are not possible due to
atmospherics
In marketing, the term atmospherics is used to describe the discipline of designing commercial spaces. Atmospherics was coined by Philip Kotler in a 1973 article in the Journal of Retailing.Kotler, P. (1973). Atmospherics as a marketing tool. Jou ...
and the nearest vessel is one
ionospheric
The ionosphere () is the ionized part of the upper atmosphere of Earth, from about to above sea level, a region that includes the thermosphere and parts of the mesosphere and exosphere. The ionosphere is ionized by solar radiation. It plays an im ...
hop away.
From ITU Radio Regulations 1990, Appendix 14: Miscellaneous Abbreviations and Signals to Be Used for Radiocommunications in the Maritime Mobile Service.
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Amateur radio
Operating signals