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 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 "INT" (dit dit dah dit dah) or suffixed it with the standard Morse question mark UD (dit dit dah dah dit dit).
- QAA–QNZ codes are reserved for aeronautical use. (Not in this database)
- QOA–QQZ codes for maritime use. (Not in this database)
- QRA–QUZ codes for all services (and all are included here).
- QVA-QZZ inclusive have not been allocated as of April 2009.
Confusingly, Amateur Radio has adapted two different sets of Q-codes for use in amateur communications. The first set comes from the ITU civil series QRA through QUZ. Most of the meanings are identical to the ITU definitions, however, they must be looked at in the context of amateur communications. For example, QSJ? asks what the charges are for sending the telegraph. Since amateur communications are without charge, this Q-code would not make sense.
The second set is the set of QN Signals, used only in ARRL NTS nets. These operating signals generally have no equivalent in the ACP 131 publication or ITU publications, and are specifically defined only for use in ARRL NTS nets. These QN Signals are defined in ARRL document FSD-218, and are not used in casual amateur radio communications, or in official CCEB ACP 131(F)-compliant communications.
Because these codes are within the Aeronautical Code signals range (QAA–QNZ) and thus conflict with official international Q signals beginning with QN, they are not included
in this searchable database.