The Q code is a set of three-letter code signals to be used in radiotelegraphy and amateur radio communications. It was developed and instituted in 1912 as a way to facilitate communication between maritime radio operators of different nationalities. For this reason, callsigns never begin with a Q.
Used in their formal "question/answer" sense, their meaning varies depending on whether they are 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 CW traffic networks.
Many militaries and other organizations that use Morse code have their own code they use besides the Q code, such as the Z code that is in use in most European and NATO countries. The Z code contains many commands and questions that are needed in military radio transmissions, that were not included in the Q codes, such as ZBW 2 (change to backup frequency nr. 2) or ZNB abc (my checksum is abc, what is yours).
For instance, in most military Morse code transmissions, any freeform text is strictly forbidden and all communications must be accomplished by the use of three-letter abbreviations, the Q and Z code.
In modern everyday amateur radio practice, the Q codes are more commonly used as shorthand nouns, verbs, or adjectives. For example, one will sometimes hear a ham complaining about QRM or telling another ham that he "has QSB on his signal"; if a ham wants you to change your operating frequency, she will ask you to QSY. Although the Q codes were created for use during Morse code operation, they are now commonly used in voice modes too. The following table gives the most common Q codes used in the amateur service, along with their meaning and sample use.
There are also a few unofficial and humorous codes floating around, such as QLF (try sending with your LEFT foot), QSC (send cigarettes) and QNB.
Q Codes used commonly used in amateur practice
||Is this frequency busy
||Used almost exclusively with Morse code
||There's another QSO up 2 kHz that's causing you a lot of QRM
||The band is noisy today; I'm hearing a lot of QRN
||Increase transmitting power
||I need to QRO when propagation is poor.
||Low(er your) transmitting power
||I'm using a QRP transmitter here, running only 3 watts
||Send your Morse code more slowly
||Please QRS, I'm new to Morse code
||I've enjoyed talking to you, but I have to QRT for dinner now
||Ready to receive
||Will you be QRV in the upcoming contest?
||Hang on a minute, I'll be right back
||Please QRX one
||Who is calling me?
||QRZ? I hear someone calling, but you're very weak
||Fading of signal
||I'm hearing a lot of QSB on your signal
||I QSL your last transmission
||A conversation with another ham
||Thanks very much for the QSO
||Let's QSY up 5 kilohertz
||My QTH is South Park, Colorado
||QTR is 2000 Z
Some of these common usages vary somewhat from their formal, official sense.
Some Q codes are also used in aviation, in particular QNH and QFE, referring to certain air pressures. These codes are used in radio conversations with air traffic control as unambiguous shorthand, where safety and efficiency are of vital importance.
See also: Common Morse code abbreviations in the Morse code article
Last updated: 05-06-2005 14:22:43