Q code
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Contents |
Overview
The Q code is a standardized collection of three-letter signals, all starting with the letter "Q", initially developed for commercial radiotelegraph communication, and later adopted by other radio services, especially amateur radio. 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 callsigns have often been limited to restrict ones starting with "Q" or having an embedded three-letter Q sequence.
Detailed Review
Early Developments
The original Q Codes were created, circa 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. (This Convention, which met in London, was signed on July 5, 1912, and became effective July 1, 1913.)
The following table reviews a sample of the Q codes adopted by the 1912 Convention:
| Abbre- viation. | Question. | Answer or Notice. |
|---|---|---|
| QRA | What ship or coast station is that? | This is ____. |
| QRB | What is your distance? | My distance is ____. |
| QRC | What is your true bearing? | My true bearing is ____ degrees. |
| QRD | Where are you bound for? | I am bound for ____. |
| QRF | Where are you bound from? | I am bound from ____. |
| QRG | What line do you belong to? | I belong to the ____ Line. |
| QRH | What is your wave length in meters? | My wave length is ____ meters. |
| QRJ | How many words have you to send? | I have ____ words to send. |
| QRK | How do you receive me? | I am receiving well. |
| QRL | Are you receiving badly? Shall I sent 20 ...-. for adjustment? | I am receiving badly. Send 20 ...-. for adjustment. |
| QRM | Are you being interfered with? | I am being interfered with. |
| QRN | Are the atmospherics strong? | Atmospherics are very strong. |
Later Usage
Over the years, modifications and additions were made to the original Q codes to reflect changes in radio practice. (In the original international list, QSW/QSX stood for "Shall I increase/decrease my spark frequency?", however, spark-gap transmitters have now been illegal for over half a century.) Many military and other organizations that use Morse code have adopted additional codes, including the Z code used by most European and NATO countries. (The Z code adds commands and questions adapted for military radio transmissions, for example, "ZBW 2" -- change to backup frequency number 2 -- or "ZNB abc" -- my checksum is abc, what is yours?). In most military Morse code transmissions, freeform text is strictly forbidden, and all communication must be accomplished using three-letter abbreviations, the Q and Z code. Used in their formal "question/answer" sense, the meaning varies depending on whether 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 Continuous Wave (CW) traffic networks.
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.
A subset of Q codes is used by Dade County, Florida law enforcement, one of the few instances where Q codes are used in ground voice communication.
Amateur Radio
Selected Q codes were soon adopted by amateur radio operators -- known informally as "hams". For example, in December, 1915 the American Radio Relay League began publication of a magazine titled QST, named after the Q code for "General call to all stations". In amateur radio, the Q codes are more commonly used as shorthand nouns, verbs, or adjectives. For example, a ham will complain about QRM (man-made interference), or tell another operator that there is "QSB on the signal"; QSY is a request to change your operating frequency.
The following table gives the most common Q codes used in the amateur service:
| Code | Meaning | Sample use |
|---|---|---|
| QRL | Is this frequency busy | Used almost exclusively with Morse code |
| QRM | Man-made interference | There's another QSO up 2 kHz that's causing you a lot of QRM |
| QRN | Static crashes | The band is noisy today; I'm hearing a lot of QRN |
| QRO | Increase transmitting power | I need to QRO when propagation is poor. |
| QRP | Low(er your) transmitting power | I'm using a QRP transmitter here, running only 3 watts |
| QRS | Send your Morse code more slowly | Please QRS, I'm new to Morse code |
| QRT | Stop sending | I've enjoyed talking to you, but I have to QRT for dinner now |
| QRV | Ready to receive | Will you be QRV in the upcoming contest? |
| QRX | Hang on a minute, I'll be right back | Please QRX one |
| QRZ | Who is calling me? | QRZ? I hear someone calling, but you're very weak |
| QSB | Fading of signal | I'm hearing a lot of QSB on your signal |
| QSL | Acknowledge receipt | I QSL your last transmission |
| QSO | A conversation with another ham | Thanks very much for the QSO |
| QSY | Change frequency | Let's QSY up 5 kilohertz |
| QTH | Location | My QTH is South Park, Colorado |
| QTR | Exact time | QTR is 2000 Z |
Some of these common usages vary somewhat from their formal, official sense. There are also a few unofficial and humorous codes in use, such as QLF ("try sending with your LEFT foot"), QSC ("send cigarettes") and QNB.
See Also
Common Morse code abbreviations in the Morse code article.
External Links
- Handbook for Wireless Telegraph Operators, October, 1909.
- Radio Laws and Regulations of the United States: Edition July 27, 1914. (Includes the 1912 London Radiotelegraphic Convention)
- ARRL amateur radio Q signals
- ITU Q code table for the maritime mobile service
- List of Q codes
