Q code

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, later also for TeleTYpe and RadioTeleTYpe and in voice communications. Most Q-codes defined in 1947 are still in use today, date back to the International Telecommunication Convention in Atlantic City, 1947 and are standardized in the ITU International Radio Regulations from 1947.

Early development

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 Second International Radiotelegraph Convention in London
The following table reviews a sample of the all-services Q-codes adopted by the 1912 convention:

Code	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 wavelength in meters?	My wavelength is ____ meters.
QRJ	How many words have you to send?	I have ____ words to send.
QRK	How do you receive me?	I am receiving. is unreadable and is perfect.
QRL	Are you busy?	I am busy.
QRM	Are you being interfered with?	I am being interfered with.
QRN	Are the atmospherics strong?	Atmospherics are very strong.

Later use

Over the years the original Q-codes were modified to reflect changes in radio practice. For example, QSW / QSX originally stood for, "Shall I increase / decrease my spark frequency?", but in the 1920s spark-gap transmitters were gradually being banned from land stations, making that meaning obsolete. By the 1970s, the Post Office Handbook for Radio Operators listed over a hundred Q-codes, covering a wide range of subjects including radio procedures, meteorology, radio direction finding, and search and rescue.
Some Q-codes are also used in aviation, in particular QNE, QNH and QFE, referring to certain altimeter settings. These codes are used in radiotelephone 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.
The QAA–QNZ code range includes phrases applicable primarily to the aeronautical service, as defined by the International Civil Aviation Organization. The QOA–QQZ code range is reserved for the maritime service. The QRA–QUZ code range includes phrases applicable to all services and is allocated to the International Telecommunication Union. QVA–QZZ are not allocated. Many codes have no immediate applicability outside one individual service, such as maritime operation or radioteletype operation.
Many military and other organisations 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", which means "change to backup frequency number 2", and "ZNB abc", which means "my checksum is abc, what is yours?"
Used in their formal question / answer sense, the meaning of a Q-code 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", whereas an unprompted statement "QRP" means "Please decrease your transmitter power". This structured use of Q-codes is fairly rare and now mainly limited to amateur radio and military Morse code traffic networks.
Under U.S. F.C.C. Regulations, CFR 47 97.113, Amateurs are not permitted to 'transmit codes or ciphers', allowing only that 'plain- language communications' may be transmitted. The term 'Q-Signal' has been historically used in that context, not 'Q-Code,' - the use of 'Code' is technically a violation of F.C.C. Regulations. This essentially examples, in the U.S. the historic separation between Amateur and Commercial/Military radio services

Use since the International Telecommunication Convention in Atlantic City, 1947

The Q-code was first specified in ITU International Radio Regulations from 1947, Appendix 9, Section 1' which defines:
While some ranges of the Q-codes are for the use of all services, some bands of Q-codes were assigned specifically for the Aeronautical Mobile and the Maritime Mobile Service, which are:
"1. The series of groups QRA to QUZ listed in this Appendix, is for use by all services."
"2. The QAA to QNZ series are reserved for the aeronautical service and the QOA to QQZ series are reserved for the maritime services. These series are not listed in these regulations."'
ICAO specified the Q-codes for aeronautical purposes initially in COM/504/1 - Doc 6100. Amendment "Communication Codes and Abbreviations. Q Code" published 1952.April.01 While not all Q-codes published in 1952 in Doc-6100 are still in use today, the Q-codes used today are documente in ICAO DOC-8400, "ICAO Abbreviations and Codes"
The Q-codes for the Maritime Mobile Service used today are documented in ITU Recommendation ITU-R M.1172, "Miscellaneous Abbreviations and Signals to be used for Radiocommunications in the Maritime Mobile Service", 1995.
"5. Abbreviations are given the form of a question when followed by a question mark. When an abbreviation is used as a question and is followed by additional or complementary information, the question mark should follow this information."
"3. Certain abbreviations may be given an affirmative or negative sense by sending “C” or “N” respectively, immediately following the “Q” code abbreviation." To distinguish the use of a Q-code transmitted in radiotelegraphy communication as a question from the same Q-code transmitted as a statement, operators either prefixed it with the military network question marker "" or suffixed it with the standard Morse question mark .
"4. The meanings assigned to “Q” code abbreviations may be amplified or completed by the addition of appropriate other groups, call signs, place names, figures, numbers, etc. It is optional to fill in the blanks shown in parentheses. Any data which is filled in where blanks appear should be sent in the same order as shown in the significations." For the Aeronautic Radio Service QNH 1015 identifies "QNH‡ "Altimeter Sub-Scale Setting to obtain Elevation when on the Ground" 1015 hPa.
"‡ ''"When radiotelephony is used, the abbreviations and terms are transmitted using the individual letters in non-phonetic form".
"7. All time should be given in Greenwich mean time unless otherwise indicated in the question or reply."'' GMT was replaced in 1972 by UTC.
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 are restricted; countries can be issued unused Q-Codes as their ITU prefix e.g. Qatar is QAT.
"Q" has no official meaning, but it is sometimes assigned a word with mnemonic value, such as "question" or "query", for example in QFE: "query field elevation".

Listing according to service

QAA to QNZ – Assigned by the International Civil Aviation Organization.
QNA to QNZ – The American Radio Relay League has also developed its own QN Signals for message handling located in this range. Even though they overlap with other signals, the ARRL determined that their exclusive use in NTS nets limits confusion.
QOA to QQZ – For the Maritime Mobile Service.
QRA to QUZ – Assigned by the International Telecommunication Union Radiocommunication Sector.''''

Aeronautical Code signals (QAA–QNZ; ICAO)

First defined in ICAO publication "Doc 6100-COM/504/1" and in "ICAO Procedures for Air Navigation Services, Abbreviations and Codes ", the majority of the Q-codes have fallen out of common use; for example today reports such as QAU and QAZ would be voice or computerised transmissions. But several remain part of the standard ICAO radiotelephony phraseology in aviation. These are also part of ACP131, which lists all ITU-R Q-codes, without grouping them by aeronautical/marine/general use. The currently applicable version of ICAO Doc-8400 has the title "Procedures for Air Navigation Services, ICAO Abbreviations"
and Codes, edition 8, 2010.November.18

	Question?	Answer or advice
QAB	May I have clearance from ____ to ____ at flight level/altitude ____ ?	You are cleared by ____ from ____ to ____ at flight level/altitude ____.
QAF	Will you advise me when you are at ____ ?	I am at ____ at flight level / altitude ____.
QAG		Arrange your flight in order to arrive over ____ at ____ hours. or I am arranging my flight in order to arrive over ____ at ____ hours.
QAH	What is your height above ____ ?	I am at ____ flight level / altitude ____. or Arrange your flight so as to reach flight level / altitude ____ at ____.
QAI	What is the essential traffic respecting my aircraft?	The essential traffic respecting your aircraft is ____.
QAK	Is there any risk of collision?	There is risk of collision.
QAL	Are you going to land at ____ ? or Has aircraft ____ landed at ____ ?	I am going to land at ____. or land at ____. or Aircraft ____ landed at ____.
QAM	What is the latest available meteorological observation for ____ ?	Meteorological observation made at ____ at ____ hours was as follows ____.
QAN	What is the surface wind direction and speed at ____ ?	The surface wind direction and speed at ____ at ____ hours is ____ ____.
QAO	What is the wind direction in degrees TRUE and speed at ____ at each of the ____ ____ levels above ____ ?	The wind direction and speed at at flight level/altitude ____ is: ____ ____ degrees TRUE ____.
QAP	Shall I listen for you on ____ kHz ?	Listen for me on ____ kHz.
QAQ	Am I near a prohibited, restricted, or danger area? or Am I near area ____ ?	You are ____ area ____. 1. near 2. flying within
QAR	May I stop listening on the watch frequency for ____ minutes?	You may stop listening on the watch frequency for ____ minutes.
QAU	Where may I jettison fuel?	I am about to jettison fuel. or Jettison fuel in ____.
QAW		I am about to carry out overshoot procedure.
QAY	Will you advise me when you pass ____ bearing 090 degrees relative to your heading?	I passed ____ bearing ____ degrees relative to my heading at ____ hours.
QAZ	Are you experiencing communication difficulties through flying in a storm?	I am experiencing communication difficulties through flying in a storm.
QBA	What is the horizontal visibility at ____ ?	The horizontal visibility at ____ at ____ hours is ____.
QBB	What is the amount, type and height above official aerodrome elevation of the base of the cloud ?	The amount, type and height above official aerodrome elevation of the base of the cloud at ____ at ____ hours is: ____ eights at ____ height above official aerodrome elevation.
QBC	Report meteorological conditions as observed from your aircraft .	The meteorological conditions as observed from my aircraft at ____ at ____ hours at ____ height above ____ are ____.
QBD	How much fuel have you remaining ?	My fuel will endure for ____.
QBE		I am about to wind in my aerial.
QBF	Are you flying in cloud?	I am flying in cloud at ____ flight level/altitude ____ .
QBG	Are you flying above cloud?	I am flying above cloud and at flight level/altitude ____. or Maintain a vertical distance of ____ above clouds, smoke, haze or fog levels.
QBH	Are you flying below cloud?	I am flying below cloud and at flight level/altitude ____. or Maintain a vertical distance of ____ below cloud.
QBI	Is flight under IFR compulsory at ____ ?	Flight under IFR is compulsory at ____ .
QBJ	What is the amount, type and height above ____ of the top of the cloud ?	At ____ hours at ____ the top of the cloud is: amount ____ eights at ____ height above ____.
QBK	Are you flying with no cloud in your vicinity?	I am flying with no cloud in my vicinity and at flight level/altitude ____.
QBM	Has ____ sent any messages for me?	Here is the message sent by ____ at ____ hours.
QBN	Are you flying between two layers of cloud?	I am flying between two layers of cloud and at flight level / altitude ____.
QBO	What is the nearest aerodrome at which flight under VFR is permissible and which would be suitable for my landing?	Flying under VFR is permissible at ____ which would be suitable for your landing.
QBP	Are you flying in and out of cloud?	I am flying in and out of cloud and at flight level/altitude ____.
QBS		Ascend to ____ height above ____ before encountering instrument meteorological conditions or if visibility falls below ____ and advise.
QBT	What is the runway visual range at ____ ?	The runway visual range at ____ at ____ hours is ____.
QBV	Have you reached flight level/altitude ____ ?	I have reached ____ flight level/altitude ____ . or Report reaching flight level/altitude ____ .
QBX	Have you left ____ flight level/altitude ____ ?	I have left ____ flight level/altitude ____ . or Report leaving flight level/altitude ____ .
QBZ	Report your flying conditions in relation to clouds.	The reply to QBZ ? is given by the appropriate answer form of signals QBF, QBG, QBH, QBK, QBN and QBP.
QCA	May I change my flight level/altitude from ____ to ____ ?	You may change your flight level/altitude from ____ to ____ or I am changing my flight level/altitude from ____ to ____.
QCB		Delay is being caused by ____. 1. you're transmitting out of turn. 2. your slowness in answering. 3. lack of your reply to my ____.
QCE	When may I expect approach clearance?	Expect approach clearance at ____ hours. or No delay expected.
QCF		Delay indefinite. Expect approach clearance not later than ____ hours.
QCH	May I taxi to ____ ?	Cleared to taxi to ____.
QCI		Make a 360-degree turn immediately. or I am making a 360-degree turn immediately.
QCS		My reception on ____ frequency has broken down.
QCX	What is your full call sign?	My full call sign is ____. or Use your full call sign until further notice.
QCY		I am working on a trailing aerial. or Work on a trailing aerial.
QDB	Have you sent message ____ to ____ ?	I have sent message ____ to ____.
QDF	What is your D-Value at ____ ? or What is the D-Value at ____ for the ____ millibar level?	My D-Value at ____ at ____ height above the 1013.2 millibars datum is ____ ____. or The D-Value at ____ at ____ hours for the ____ millibar level is ____.
QDL	Do you intend to ask me for a series of bearings?	I intend to ask you for a series of bearings.
QDM	Will you indicate the magnetic heading for me to steer towards you with no wind?	The magnetic heading for you to steer to reach me with no wind was ____ degrees.
QDP	Will you accept control of ____ now ?	I will accept control of ____ now.
QDR	What is my magnetic bearing from you ?	Your magnetic bearing from me was ____ degrees.
QDT	Are you flying in visual meteorological condition?	I am flying in visual meteorological condition. or You are cleared subject to maintaining own separation and visual meteorological conditions.
QDU		Cancelling my IFR flight. or IFR flight cancelled at ____.
QDV	Are you flying in a flight visibility of less than ____ ?	I am flying in a flight visibility of less than ____ at flight level/altitude ____
QEA	May I cross the runway ahead of me?	You may cross the runway ahead of you.
QEB	May I turn at the intersection?	Taxi as follows at the intersection ____. .
QEC	May I make a 180-degree turn and return down the runway?	You may make a 180-degree turn and return down the runway.
QED	Shall I follow the pilot vehicle?	Follow the pilot vehicle.
QEF	Have I reached my parking area? or Have you reached your parking area?	You have reached your parking area. or I have reached my parking area.
QEG	May I leave the parking area? or Have you left the parking area?	You may leave the parking area. or I have left the parking area.
QEH	May I move to the holding position for runway number ____ ? or Have you moved to the holding position for runway number ____ ?	Cleared to the holding position for runway number ____ or I have moved to the holding position for runway number ____.
QEJ	May I assume position for take-off? or Have you assumed position for take-off?	Cleared to hold at take-off position for runway number ____. or I am assuming take-off position for runway number ____ and am holding.
QEK	Are you ready for immediate take-off?	I am ready for immediate take-off.
QEL	May I take-off ?	You are cleared to take-off.
QEM	What is the condition of the landing surface at ____ ?	The condition of the landing surface at ____ is ____.
QEN	Shall I hold my position?	Hold your position
QEO	Shall I clear the runway ? or Have you cleared the runway ?	Clear the runway. or I have cleared the runway.
QES	Is a right-hand circuit in force at ____ ?	A right-hand circuit is in force at ____.
QFA	What is the meteorological forecast for ____ for the period ____ hours until ____ hours?	The meteorological forecast for ____ approach 2) runway 3) approach and runway lights are out of order.
QFC	What is the amount, the type and the height above ____ of the base of the cloud at ____ ?	At ____ the base of the cloud is ____ eighths ____ type at ____ height above ____.
QFD	1. Is the ____ visual beacon in operation? 2. Will you switch on the ____ visual beacon ? 3. Will you extinguish the aerodrome visual beacon until I have landed?	1. The ____ visual beacon is in operation 2. I will extinguish the aerodrome visual beacon until your landing is completed.
QFE	What should I set on the subscale of my altimeter so that the instrument would indicate its height above the reference elevation being used?	If you set the subscale of your altimeter to read ____ millibars, the instrument would indicate its height above aerodrome elevation.
QFF	what is the present atmospheric pressure converted to mean sea level in accordance with meteorological practice?	At ____ the atmospheric pressure converted to mean sea level in accordance with meteorological practice is ____ millibars.
QFG	Am I overhead?	You are overhead.
QFH	May I descend below the clouds?	You may descend below the clouds.
QFI	Are the aerodrome lights lit?	The aerodrome lights are lit. or Please light the aerodrome lights.
QFL	Will you send up pyrotechnical lights?	I will send up pyrotechnical lights.
QFM	What flight level/altitude ____. 1. should I maintain? 2. are you maintaining? 3. do you intend cruising at?	____ ____. 1. Maintain flight level / altitude ____. 2. I am maintaining flight level / altitude ____ 3. I intend cruising at flight level/altitude ____.
QFO	May I land immediately?	You may land immediately.
QFP	Will you give me the latest information concerning ____ facility ?	The latest information concerning ____ facility is as follows ____.
QFQ	Are the approach and runway lights lit?	The approach and runway lights are lit. or Please light the approach and runway lights.
QFR	Does my landing gear appear damaged?	Your landing gear appears damaged.
QFS	Is the radio facility at ____ in operation?	The radio facility at ____ is in operation. or Please have the ____ radio facility at ____ put in operation.
QFT	Between what heights above ____ has ice formation been observed ?	Ice formation has been observed at ____ in the type of ____ and with an accretion rate of ____ between ____ and ____ heights above ____.
QFU	What is the magnetic direction of the runway to be used?	The magnetic direction of the runway to be used is ____.
QFV	Are the floodlights switched on?	The floodlights are switched on. or Please switch on the floodlights.
QFW	What is the length of the runway in use in ____ ?	The length of runway ____ now in use is ____.
QFX		I am working on a fixed aerial. or Work on a fixed aerial.
QFY	Please report the present meteorological landing conditions .	The present meteorological landing conditions at ____ are ____.
QFZ	What is the aerodrome meteorological forecast for ____ for the period ____ hours until ____ hours?	The aerodrome meteorological forecast for ____ for the period ____ hours until ____ hours is ____.
QGC		There are obstructions to the ____ of ____ runway ____.
QGD	Are there on my track any obstructions whose elevation equals or exceeds my altitude?	There are obstructions on your track ____ height above ____.
QGE	What is my distance to your station ?	Your distance to my station is ____.
QGH	May I land using ____ ?	You may land using ____.
QGK	What track should I make good? or What track are you making good?	Make good a track from ____ on ____ degrees ____. or I am making good a track from ____ on ____ degrees ____.
QGL	May I enter the ____ at ____ ?	You may enter the ____ at ____.
QGM		Leave the ____.
QGN	May I be cleared to land ?	You are cleared to land .
QGO		Landing is prohibited at ____.
QGP	What is my number for landing?	You are number ____ to land.
QGQ	May I hold at ____ ?	Hold at ____ at flight level/altitude ____ and await further clearance.
QGT		Fly for ____ minutes on a heading what will enable you to maintain a track reciprocal to your present one.
QGU		Fly for ____ minutes on a magnetic heading of ____ degrees.
QGV	Do you see me? or Can you see the aerodrome? or Can you see ____ ?	I see you at ____. or I can see the aerodrome. or I can see ____.
QGW	Does my landing gear appear to be down and in place?	Your landing gear appears to be down and in place.
QGZ		Hold on ____ direction of ____ facility.
QHE	Will you inform me when you are on ____ leg of approach?	I am on ____ of approach. 1. cross-wind leg 2. down-wind leg 3. base leg 4. final leg
QHG	May I enter traffic circuit at flight level/altitude ____?	Cleared to enter traffic circuit at flight level/altitude ____.
QHH	Are you making an emergency landing?	I am making an emergency landing. or Emergency landing being made at ____. All aircraft below flight level/altitude ____ and within a distance of ____ leave ____.
QHI	Are you ____. 1. waterborne? 2. on land?	I am ____ at ____ hours. 1. waterborne 2. on land
QHQ	May I make a ____ approach ? or Are you making a ____ approach?	You may make a ____ approach . or I am making a ____ approach.
QHZ	Shall I circle the aerodrome ?	Circle the aerodrome.
QIC	May I establish communication with ____ radio station on ____ kHz ?	Establish communication with ____ radio station on ____ kHz. . or I will establish communication with ____ radio station on ____ kHz .
QIF	What frequency is ____ using?	____ is using ____ kHz.
QJA	Is my ____ reversed? 1. tape 2. mark and space	Your ____ is reversed. 1. tape 2. mark and space
QJB	Will you use ____. 1. radio? 2. cable? 3. telegraph? 4. teletypewriter? 5. telephone? 6. receiver? 7. transmitter? 8. reperforator?	I will use ____. 1. radio. 2. cable. 3. telegraph. 4. teletypewriter. 5. telephone. 6. receiver. 7. transmitter. 8. reperforator.
QJC	Will you check your ____. 1. transmitter distributor? 2. auto-head? 3. perforator? 4. reperforator? 5. printer? 6. printer motor? 7. keyboard? 8. antenna system?	I will check my ____. 1. transmitter distributor. 2. auto-head. 3. perforator. 4. reperforator. 5. printer. 6. printer motor. 7. keyboard. 8. antenna system.
QJD	Am I transmitting ____. 1. in letters? 2. in figures?	You are transmitting ____. 1. in letters 2. in figures.
QJE	Is my frequency shift ____. 1. too wide? 2. too narrow? 3. correct?	Your frequency shift is ____. 1. too wide. 2. too narrow. 3. correct.
QJF		My signal as checked by monitor ____ is satisfactory ____. 1. locally. 2. as radiated.
QJG	Shall I revert to automatic relay?	Revert to automatic relay.
QJH	Shall I run ____ 1. my test tape? 2. a test sentence?	Run ____ 1. your test tape. 2. a test sentence.
QJI	Will you transmit a continuous ____. 1. mark? 2. space?	I am transmitting a continuous ____. 1. mark. 2. space.
QJK	Are you receiving ____. 1. a continuous mark? 2. a continuous space? 3. a mark bias? 4. a space bias?	I am receiving ____. 1. a continuous mark. 2. a continuous space. 3. a mark bias. 4. a space bias.
QKC		The sea conditions ____. 1. permit alighting but not take-off. 2. render alighting extremely hazardous.
QKF	May I be relieved ?	You may expect to be relieved at ____ hours . 1. aircraft ____ 2. and / or .
QKG	Will relief take place when ____ establishes ____. 1. visual, 2. communications, contact with survivors?	Relief will take place when ____ establishes ____. 1. visual, 2. communications, contact with survivors.
QKH	Report details of the parallel sweep search being conducted? or In the parallel sweep search being conducted, what is ____. 1. the direction of sweeps, 2. the separation between sweeps, 3. the flight level/altitude ____ employed in the search pattern?	The parallel sweep search is being conducted ____. 1. with direction of sweeps ____ degrees ____. 2. with ____ separation between sweeps. 3. at flight level/altitude ____.
QKN		Aircraft plotted in position ____ on track ____ degrees at ____ hours.
QKO	What other units are taking part in the operation ?	In the operation, the following units are taking part ____. or ____ unit is taking part in operation as observed from your aircraft.	The vertical distribution of cloud as observed from my aircraft at ____ hours at ____. is : lowest layer observed* ____ eights with base of ____ and tops of ____ height above ____.
QMU	What is the surface temperature at ____ and what is the dew point temperature at that place?	The surface temperature at ____ at ____ hours is ____ degrees and the dew point temperature at that time and place is ____ degrees.
QMW	At ____ what is the flight level/altitude ____ of the zero Celsius isotherm?	At ____ the zero Celsius isotherm is at flight level/altitude ____.
QMX	What is the air temperature at flight level/altitude ____?	At ____ at ____ hours the air temperature is ____ at flight level/altitude ____.
QMZ	Have you any amendments to the flight forecast in respect of section of route yet to be traversed?	The following amendment should be made to the flight forecast ____.
QNE	What indication will my altimeter give on landing at ____ at ____ hours, my sub-scale being set to 1013.2 millibars ?	On landing at ____ at ____ hours, with your sub-scale being set to 1013.2 millibars, your altimeter will indicate ____.
QNH	What should I set on the subscale of my altimeter so that the instrument would indicate its elevation if my aircraft were on the ground at your station?	If you set the subscale of your altimeter to read ____ millibars, the instrument would indicate its elevation if your aircraft were on the ground at my station at ____ hours.
QNI	Between what heights above ____ has turbulence been observed at ____ ?	Turbulence has been observed at ____ with an intensity of ____ between ____ and ____ heights above ____.
QNO		I am not equipped to give the information requested.
QNR		I am approaching my point of no return.
QNT	What is the maximum speed of the surface wind at ____ ?	The maximum speed of the surface wind at ____ at ____ hours is ____.
QNY	What is the present weather and the intensity thereof at ____ ?	The present weather and intensity thereof at ____ at ____ hours is ____.

Maritime Mobile Service (QOA–QQZ)

This assignment is specified in RECOMMENDATION ITU-R M.1172.
Q signals are not substantially used in the maritime service. Morse code is now very rarely used for maritime communications, but in isolated maritime regions like Antarctica and the South Pacific the use of Q-codes continues. Q-codes still work when HF voice circuits are not possible due to atmospherics and the nearest vessel is one ionospheric hop away.

All services (QRA–QUZ)

First defined by the Washington 1927 ITU Radio Regulations. Later defined by ITU-R in Appendix 9 to the Radio Regulations Annex to the International Telecommunications Convention. The current callsign table is found in ITU-R Appendix 42. Current interpretation of the Q-code can be found in ITU-R Appendices 14 and 15.
ITU Radio Regulations 1990, Appendix 13: Miscellaneous Abbreviations and Signals to be Used in Radiotelegraphy Communications Except in the Maritime Mobile Service:

Amateur radio

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 by regulation amateur communications are without charge, this Q-code couldn't 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. They are not used in casual amateur radio communications.
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.
Q-codes are commonly used in voice communications as shorthand nouns, verbs, and adjectives making up phrases. For example, an amateur radio operator will complain about QRM, or tell another operator that there is "QSB on the signal" ; "to QSY" is to change your operating frequency, or to break in on a conversation QSK is often used even on VHF and UHF frequencies.

Q-codes as adapted for use in amateur radio

Code	Question	Answer or statement
QRA	What is the name of your station?	The name of my station is ____
QRG	Will you tell me my exact frequency ?	Your exact frequency is ____ kHz.
QRH	Does my frequency vary?	Your frequency varies.
QRI	How is the tone of my transmission?	The tone of your transmission is
QRJ	How many voice contacts do you want to make?	I want to make ____ voice contacts.
QRK	What is the readability of my signals ?	The readability of your signals is ____.
QRL	Are you busy?	I am busy. Please do not interfere.
QRM	Do you have interference?	I have interference.
QRN	Are you troubled by static?	I am troubled by static.
QRO	Shall I increase power?	Increase power.
QRP	Shall I decrease power?	Decrease power.
QRQ	Shall I send faster?	Send faster.
QRS	Shall I send more slowly?	Send more slowly.
QRT	Shall I stop sending?	Stop sending. Often heard colloquially as: I am suspending operation / shutting off the radio.
QRU	Have you anything for me?	I have ____ messages for you.
QRV	Are you ready?	I am ready.
QRW	Shall I inform ____ that you are calling on ____ kHz ?	Please inform ____ that I am calling on ____ kHz.
QRX	Shall I standby? / When will you call me again?	Please standby / I will call you again at ____ on ____ kHz
QRZ	Who is calling me?	You are being called by ____ on ____ kHz
QSA	What is the strength of my signals ?	The strength of your signals is ____.
QSB	Are my signals fading?	Your signals are fading.
QSD	Is my keying defective?	Your keying is defective.
QSG	Shall I send ____ telegrams at a time?	Send ____ telegrams at a time.
QSK	Can you hear me between your signals?	I can hear you between my signals.
QSL	Can you acknowledge receipt?	I will acknowledge receipt.
QSM	Shall I repeat the last telegram which I sent you, or some previous telegram ?	Repeat the last telegram which you sent me / message numbers.
QSN	Did you hear me on ____ kHz ?	I did hear you on ____ kHz.
QSO	Can you communicate with ____ direct or by relay?	I can communicate with ____ direct.
QSP	Will you relay a message to ____ ?	I will relay a message to ____.
QSR	Do you want me to repeat my call?	Please repeat your call; I did not hear you.
QSS	What working frequency will you use?	I will use the working frequency ____ kHz.
QST	Should I repeat the prior message to all amateurs I contact?	Here follows a broadcast message to all amateurs.
QSU	Shall I send or reply on this frequency ?	Send or reply on this frequency.
QSW	Will you send on this frequency ?	I am going to send on this frequency.
QSX	Will you listen to ____ on ____ kHz )?	I am listening to ____ on ____ kHz )
QSY	Shall I change to transmission on another frequency?	Change to transmission on another frequency.
QSZ	Shall I send each word or group more than once?	Send each word or group twice.
QTA	Shall I cancel telegram number ____ as if it had not been sent?	Cancel telegram number ____ as if it had not been sent.
QTC	How many telegrams have you to send?	I have ____ telegrams for you.
QTH	What is your position in latitude and longitude?	My position is ____ latitude ____ longitude.
QTR	What is the correct time?	The correct time is ____ hours UTC.
QTU	At what times are you operating?	I am operating from ____ to ____ hours.
QTX	Will you keep your station open for further communication with me until further notice ?	I will keep my station open for further communication with you until further notice.
QUA	Have you news of ____ ?	Here is news of ____.
QUC	What is the number of the last message you received from me ?	The number of the last message I received from you is ____.
QUD	Have you received the urgency signal sent by ____ ?	I have received the urgency signal sent by ____ at ____ hours.
QUE	Can you speak in ____ – with interpreter if necessary – if so, on what frequencies?	I can speak in ____ on ____ kHz.
QUF	Have you received the distress signal sent by ____ ?	I have received the distress signal sent by ____ at ____ hours.

Informal usage

Image:International Morse Code.svg|right|thumb|315px|Chart of the Morse code letters and numerals.
QAC - Taken from the Articles of Association of the South Hampshire International Telegraphy Society, para 9: "...and amongst themselves they shall promote the Use of the Code QAC, which shall be taken as implying "All Compliments" and shall include:- VY 73 73 OM CUL BCNU & mni tnx fer nice/FB/rotten QSO GL GB hpe cuagn wid gud/btr/wrse condx mri Xms Hpi Nw Yr mni hpi rtrns gtgs fer Rosh Hoshanah/Id el Fitr/May Day/Tksgvg 88 to XYL/YL/Widow Ciao Cheerio & gud/FB/best DX or any Part or Parts thereof in any Permutation or Combination.
QLF – "Are you sending with your left foot? Try sending with your left foot!" A humorously derogatory comment about the quality of a person's sending.
QNB – QNB? “How many buttons on your radio?” “QNB 100/5” Means there are 100 and I know what 5 of them do.
QSK – "I can hear you during my transmission" – refers to a particular mode of Morse code operating often called QSK operation (full break-in) in which the receiver is quickly enabled during the spaces between the dits and dahs, which allows another operator to interrupt transmissions. Many modern 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.
QSY – "Change to transmission on another frequency"; colloquially, "move ". E.g., "When did QSY from Northolt to Portishead?"
QTH – "My location is ____"; colloquially in voice or writing, "location". E.g., "The OCF ' is an interesting build but at my QTH a disappointing performer."
QTHR – "At the registered location ____"; chiefly British use. Historically, the location in the printed Callbook; modernly, "as given in online government records for my callsign". E.g., "You can contact me QTHR".
QBL''' – “Quit Being a Lid”. QBL is used among amateur radio operators to indicate humor in their CW transmission. While QBL is generally used by a small subsection of operators who can properly decode, it is available to anyone. "Lid" is said to be short for "Literal Idiot". The QBL moniker has been adopted by some radio operators as a term of endearment, like the .

German use during World War II

During World War II, according to Bletchley Park’s General Report on Tunny, German radio teleprinter networks used Q-codes to establish and maintain circuit connections.
In particular: QEP was to indicate the Lorenz cipher machine setting for each message and, QZZ to indicate that the daily key change was about to take place at the sender's station.