Q code Totally Explained

Everything about Q Codes totally explained

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.

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 .	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 signalizing that callers can break in at any time)
QSL	I Acknowledge receipt	QSL UR LAST TX = PSE QSL VIA BURO (for example 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'm 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's 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's 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's what's happening. The reason QRZ is used instead of the more correct QSX is that QSX isn't normally used in voice communications while QRZ is used extensively.

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

Further Information

Get more info on 'Q Codes'.

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