The Q-Code is a standardised collection of three-letter message encoding, also known as a Brevity Code, (Brevity Codes are used in amateur radio, maritime, aviation and military communications. The codes are designed to convey complex information with a few words or codes, all of which start with the letter “Q”), initially developed for commercial radiotelegraph communication, and later adopted by other radio services, especially amateur radio. Although QCodes 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 are restricted; while an embedded three-letter Q sequence may occur (for instance when requested by an amateur radio station dedicated to low-power operation), no country is ever issued an ITU prefix starting with “Q”, (The International Telecommunication Union [ITU] allocates call sign prefixes for radio and television stations of all types). The codes in the range QAA–QNZ are reserved for aeronautical use; QOA–QQZ for maritime use and QRA–QUZ for all services.
The original Q-Codes were created, about 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 in London (The Convention was signed on July 5, 1912, and became effective July 1, 1913.)
Over the years, modifications were made to the original Q-Codes to reflect changes in radio practice. Over a hundred Q-Codes were listed in the Post Office Handbook for Radio Operators in the 1970s and cover subjects such as meteorology, radio direction finding, radio procedures, search and rescue, and so on.
Some Q-Codes are also used in aviation and some in maritime. (A subset of Q-Codes is used by the Miami-Dade County, Florida local government for law enforcement and fire rescue communications, one of the few instances where Q-codes are used in ground voice communication.) Many military and other organizations that use Morse Code have adopted additional codes, including the Z-Code used by most European and NATO countries. Used in their formal “question/answer” sense, the meaning of a Q-code varies depending on whether or not the individual Q-code is sent as a question or an answer. For example, the message “QRP?” means “Shall I decrease transmitter power?”, and a reply of “QRP” means “Yes, decrease your transmitter power”. This structured use of Q-codes is fairly rare and now mainly limited to amateur radio and military Morse Code (CW) traffic networks.
Breakdown by Service •
QAA to QNZ – Assigned by the International Civil Aviation Organization (ICAO). •
QOA to QQZ – Reserved for the Maritime Services.
QRA to QUZ – Assigned by the International Telecommunications Union (ITU). •
QVA–QZZ – Are not allocated.
Selected Q-Codes were soon adopted by Amateur Radio Operators. In December, 1915, the American Radio Relay League (ARRL) began publication of a magazine titled “OST”, named after the Q-Code for “General call to all stations”. In Amateur Radio, the Q-Codes were originally used in Morse Code transmissions to shorten lengthy phrases and were followed by a Morse Code question mark (··–··) if the phrase was a question.
Q-Codes are commonly used in voice communications as shorthand nouns, verbs, and adjectives making up phrases. For example, an Amateur Radio Operator will complain about QRM (manmade interference), or tell another operator that there is “QSB on the signal”; “to QSY” is to change your operating frequency.
They can still be heard on HF communications but are not normally used on UHF and VHF communications. The reason is quite simple. Many radio amateurs have become certified purely to be volunteer communicators for their local emergency programs and consequently are not very familiar with the Q-Codes. Recently Q-Codes have again been used more for Morse Code communications than for voice communications.