Editing Q code (section)

{{short description|Type of Morse code operating signal}}
{{distinguish|QR code|Wikidata#Main parts}}
{{redirect|QRO|the airport in Mexico|Querétaro International Airport}}
{{engvarB|date=April 2021}}{{use dmy dates|date=May 2023}}

The '''Q-code''' is a standardised collection of three-letter codes that each start with the letter "Q". It is an [[Operating signals|operating signal]] initially developed for commercial [[radiotelegraphy|radiotelegraph]] communication and later adopted by other radio services, especially [[amateur radio]]. To distinguish the use of a Q-code transmitted as a question from the same Q-code transmitted as a statement, operators either prefixed it with the military network question marker "{{overline|INT}}" ({{morse|dot|dot|dash|dot|dash}}) or suffixed it with the standard Morse question mark {{overline|UD}} ({{morse|dot|dot|dash|dash|dot|dot}}).

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 sign]]s are restricted; countries can be issued unused Q-Codes as their [[ITU prefix]] e.g. [[List of ITU letter codes|Qatar is QAT]].

Codes in the range QAA–QNZ are reserved for aeronautical use; QOA–QQZ for maritime use and QRA–QUZ for all services.

"Q" has no official meaning, but it is sometimes assigned a word with [[mnemonic]] value, such as "question" or "query", for example in QFE: "query field elevation".<ref>{{cite web |url=http://www.boeing.com/commercial/aeromagazine/aero_16/polar_story.html |title=Aero 16 – Polar Route Operations|first=277808-Elizabeth A. |last=Franklin |access-date=5 September 2016 |url-status=dead |archive-url=https://web.archive.org/web/20011113093037/https://www.boeing.com/commercial/aeromagazine/aero_16/polar_story.html |archive-date=13 November 2001}}</ref>