Q code

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"QRO" redirects here. For the airport in Mexico, see Querétaro International Airport.

The Q code is a standardised collection of three-letter message encodings, 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 call signs have often been limited to restrict ones starting with "Q" or having an embedded three-letter Q sequence. The codes in the range QAA-QNZ are reserved for aeronautical use; QOA-QOZ for maritime use, and QRA-QUZ for all services.

Contents

[edit] 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 all-services Q codes adopted by the 1912 Convention:

First Twelve Q Codes Listed in the 1912 International Radiotelegraph Convention Regulations

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 send 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.

[edit] Later usage

Over the years, modifications 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 were banned in the United States in the 1920s, rendering the original meaning of those Q codes obsolete. Over a hundred Q codes were listed in the 'Post Office Handbook for Radio Operators' in the 1970's and cover subjects such as meteorology, radio direction finding, radio procedures, search & rescue and so on.

Some Q codes are also used in aviation, in particular QNH and QFE, referring to certain altimeter settings. 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 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. 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?

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.

[edit] Amateur radio

Selected Q codes were soon adopted by amateur radio operators. 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 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. In voice communications, the Q code is commonly used as shorthand nouns, verbs and adjectives making up phrases. For example, an amateur radio operator will complain about QRM (man-made interference), or tell another operator that there is "QSB on the signal"; "to QSY" is to change your operating frequency.

The following table gives the most common Q codes used in amateur radio:

Q Codes Commonly Used by Radio Amateurs

Code Meaning Sample use
QRG Exact frequency HE TX ON QRG 14205 kHz
QRI Tone (T in the RST code) UR QRI 9
QRK Intelligibility (R in the RST code) UR QRK 5
QRL This frequency is busy. QRL? Used almost exclusively with Morse code, usually before transmitting on a new frequency
QRM Man-made interference PSE AGN HR QRM
QRN Natural interference, e.g. static crashes BAND NOISY TODAY LOTS OF QRN
QRO Increase power NEED QRO WHEN PROP POOR
QRP decrease power QRP TO 5 W
QRQ Send faster TIME SHORT PSE QRQ
QRR temporarily unavailable/away, please wait WILL BE QRR 30 MIN = THAT STN IS QRR NW
QRRR Distress Distress call recommended by ARRL
QRS Send slower PSE QRS NEW TO CW
QRT Stop sending ENJOYED TALKING 2 U = MUST QRT FER DINNER NW
QRU Have you anything for me? QRU? ABOUT TO QRT
QRV I am ready WL U BE QRV IN UPCOMING CONTEST?
QRX will call you again QRX 5 MIN
QRZ You are being called by ________. QRZ? (Only someone who has previously called should reply)
QSA Signal strength UR QSA 5
QSB Fading of signal THERE IS QSB ON UR SIG
QSD Your keying is defective QSD CK YR TX
QSK Break-in CQ DE W1AW W1AW QSK CQ DE ... (W1AW indicating that callers can break in at any time)
QSL I Acknowledge receipt QSL UR LAST TX = PSE QSL VIA BURO (i.e. please send me a card confirming this contact).
QSM Repeat last message QRM DROWNED UR LAST MSG OUT = PSE QSM
QSN I heard you QSN YESTERDAY ON 7005 kHz
QSO A conversation TNX QSO 73
QSP Relay PSE QSP THIS MSG TO MY FRIEND
QST General call to all stations QST: QRG ALLOCS HV CHGD
QSX I am listening on ... frequency QSX 14200 TO 14210 kHz
QSY Shift to transmit on ... PSE QSY UP 5 kHz
QTA Disregard last message QTA, DID NOT MEAN THAT
QTC Traffic STN WID EMRG QTC PSE GA
QTH Location QTH SOUTH PARK CO
QTR Exact time QTR 2000Z

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") and QSC ("send cigarettes", not the official meaning of "this is a cargo vessel"). In the question form, QNB?, is supposed to mean "How many buttons does your radio have?" A reply of the form QNB 45/15 means "45, and I know what 15 of them do." QRK is sometimes used to refer to the cost of something - "I would like an FT9000 but it is too much QRK".

QSK - "I can hear you during my transmission" - refers to a particular mode of Morse code operating in which the receiver is enabled during the spaces between dots while transmitting. Some transceivers incorporate this function, sometimes referred to as full break-in as against semi-break-in in which there is a short delay before the transceiver goes to receive.

Some ham operators within the USA, particularly those traveling long distances, will monitor the National 2-meter FM calling frequency of 146.520 MHz while in their vehicles. If you see a vehicle on the road with a bumper-sticker, license plate or other sign that says QRZ 52? and a few extra antennas, that is what's happening. The reason QRZ is used instead of the more correct QSX is that QSX is not normally used in voice communications while QRZ is used extensively.

[edit] Aviation

Although the majority of the Q codes have slipped out of common use, several remain part of the standard ICAO radiotelephony phraseology in aviation.

Altimeter Settings

Code Meaning Sample use
QFE Atmospheric pressure at airfield elevation Runway in use 22 Left, QFE 990
QNE Atmospheric pressure at sea level in the International Standard Atmosphere (1013.25 mbar)
QNH Atmospheric pressure at mean sea level Request QNH

Radio Navigation

Code Meaning Sample use
QDM Magnetic bearing to a station QDM QDM QDM (callsign) request QDM
QDR Magnetic bearing from a station
QFU Runway in use Runway 22 in use, QFU 22
QTE True bearing from a station
QUJ True bearing to a station

Radio Procedures

Code Meaning Sample use
QSY Free-call another frequency (not anymore official part of the standard phraseology, but still regularly heard) Golf Alpha Bravo QSY Doncaster 126.225

[edit] See also

[edit] External links

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International Morse code
Transmission methods
Notable signals
Other writing systems
in Morse code