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Q code

The Q code is a standardized collection of three-letter abbreviations, each beginning with the letter "Q", designed as operating signals to facilitate concise radiotelegraph communication by encoding common questions, descriptions, and instructions. Originating from the Radiotelegraph Convention in , where it was instituted by the British Post Office as a system for transmissions between ships and coastal stations, the Q code was primarily developed for services to ensure clarity and efficiency across languages and amid potential signal . Over time, the (ITU) formalized and expanded the codes through recommendations such as M.1172, reserving series like QOA–QQZ for use and extending them to aeronautical and other radiocommunication contexts, with provisions for affirmative ("C"), negative ("NO"), or interrogative ("?") modifications. In , known as Q-signals, these codes were adopted early in the and remain a cornerstone of () operations, as well as voice communications, allowing operators worldwide to exchange operational details succinctly—such as QRM? (Are you being interfered with?) or QSL (I acknowledge receipt). The system encompasses over 100 codes, categorized by service: maritime-focused ones like QRB (What is the approximate distance between our stations?) for , aeronautical variants like QDM (What is my magnetic bearing from you?) defined by the (ICAO), and general signals like CQ (calling all stations) that predate the formal Q code but integrated into it. While digital modes and voice protocols have reduced reliance on Q codes in some areas, they persist in emergency communications, international contests, and as a cultural tradition in radiotelegraphy, underscoring their enduring role in global wireless brevity.

History and Development

Early Development

The Q codes originated in 1909 when the Post Office developed a standardized list of three-letter abbreviations beginning with "Q" specifically for , aimed at improving efficiency in communications between British ships and licensed coast stations. This initiative addressed the challenges of international radiotelegraph exchanges, where operators from diverse linguistic backgrounds needed concise, unambiguous signals to transmit operational queries, responses, and procedural instructions over . The system was initially prepared as a "List of abbreviations ... for the use of British ships and coast stations licensed by the ," marking a pivotal step in formalizing for commercial shipping operations. The codes gained their first international endorsement at the Second International Radiotelegraph Convention held in in 1912, where delegates from multiple nations adopted an initial set of 45 Q codes to establish a uniform framework for global radiotelegraph procedures. This convention, convened shortly after the disaster highlighted the need for reliable signaling, integrated the abbreviations into international regulations, ensuring their applicability across commercial and governmental services. The adopted codes focused on essential functions, such as identifying stations, assessing signal quality, and coordinating transmissions, thereby reducing transmission time and errors in high-stakes environments. During , Q codes underwent practical expansion in military signaling, adapting the maritime framework for wartime radiotelegraph needs in naval and ground operations. Codes like QRA, which inquired about the name of a station ("What is the name of your station?"), and QSL, used to confirm ("I acknowledge "), proved invaluable for secure and rapid coordination amid the chaos of communications. This period saw increased adoption by armed forces, building on the standards to support tactical exchanges in diverse theaters. Pioneering figures contributed to this foundational phase: Admiral Sir Henry Jackson, a key British naval officer, influenced early protocols through his experimental work on shipboard transmissions in the late 1890s and early 1900s, laying groundwork for standardized signaling systems that enabled later developments like the Q codes. Complementing this, the drove practical implementation by equipping merchant and with wireless apparatus.

Standardization and Evolution

The formal international standardization of Q codes took place at the International Radiotelegraph Conference in in , where the annexed Radio Regulations included an appendix defining a comprehensive list of Q abbreviations for use in radiotelegraph communications. This marked an expansion from the initial set established in earlier conventions, resulting in over 100 codes organized by service categories, such as those reserved for maritime mobile (QOA–QQZ) and aeronautical mobile operations. The (ITU), as the successor to earlier international bodies, assumed responsibility for maintaining and periodically revising the Q codes through its radio conferences. Notable updates occurred at the International Radiocommunication Conference in in 1938, which revised the overall Radio Regulations including operating signals, and at the International Radio Conference in Atlantic City in 1947, where specific revisions to the Q code list were debated and incorporated into Appendix 9 of the regulations. These efforts ensured the codes' consistency across global services while adapting to technological and operational needs. During , temporary expansions to the Q codes were introduced to address urgent communication requirements, leading to post-war reviews that integrated select additions into the standardized list without altering the core framework. Originally designed for radiotelegraphy, the codes evolved to support radiotelephony as voice transmission grew dominant in the mid-20th century; by the late 1960s, their mandatory application diminished in many non-safety contexts due to the efficiency of direct voice procedures, though they remained essential in aeronautical services for brevity and clarity.

Structure and Usage Principles

Format and Classification

Q codes consist of three-letter combinations that begin with the letter "Q" followed by two additional letters, forming abbreviations designed for concise communication, particularly in where their brevity reduces transmission time and minimizes errors. This standardized format originated from early 20th-century radio practices and was formalized by international bodies to ensure across services. For instance, codes like QSL or QTH exemplify the structure, allowing operators to convey complex ideas with minimal characters. The codes are classified into distinct ranges based on their intended primary service, as established by the (ITU) and the (ICAO). The range QAA–QNZ is reserved for aeronautical communications, covering procedures related to aviation operations such as altimeter settings and navigation queries. The QOA–QQZ range is allocated to the maritime mobile service, addressing ship-to-ship and ship-to-shore interactions including distress signals and position reporting. Finally, the QRA–QUZ range serves general purposes applicable to all radiocommunication services, including acknowledgments and operational status updates, and is not restricted to a single domain. These classifications prevent overlap and promote specialized usage while allowing cross-service applicability where appropriate. Procedurally, Q codes function as questions, statements, or replies depending on context and . In radiotelegraphy, a followed by a (e.g., QSL?) poses an inquiry, such as "Shall I acknowledge ?"; without the mark, it serves as a statement (e.g., QSL meaning "I acknowledge "). In radiotelephony, questions are indicated by the prosign "RQ" ( ). Replies to questions typically repeat the code affirmatively or use supplementary signals like "C" for yes or "NO" for negative, ensuring clear confirmation. Additional information, such as figures or call signs, may follow the code in parentheses for elaboration, maintaining the system's efficiency in high-stakes transmissions. Times are expressed in UTC unless otherwise specified, and codes may include numbered options (e.g., 0–9) for alternatives. This logical structure supports rapid exchange in , where each code equates to a short sequence of dots and dashes.

Response Protocols

In radiocommunications, Q codes follow standardized response protocols to affirm or negate inquiries, ensuring clarity and efficiency across services such as , aeronautical, and . When a Q code is posed as a question—indicated by a trailing "?" in or "RQ" in voice—the reply adopts the code's statement form for affirmation or a specific negation structure. These protocols, outlined in international standards, allow operators to confirm actions or conditions without lengthy explanations. Affirmative responses commonly use "QSL" to acknowledge receipt of a message or transmission, directly replying to queries like "QSL?" (Can you acknowledge ?). For other codes, affirmation is achieved by restating the code in its declarative sense; for example, responding to "QRT?" (Shall I stop sending?) with "QRT" confirms the station is ceasing . In some contexts, such as maritime mobile service, an affirmative sense can be explicitly added by following the code with "C" (for "," meaning yes). These methods prioritize immediate confirmation to maintain operational flow. Negative responses typically incorporate "NIL" to indicate absence or negation, as in replying to "QRM?" (Is my transmission being interfered with?) with "QRM NIL" (no interference). Alternatively, the code can be followed by "NO" to convey denial, per procedures in ITU Radio Regulations appendices; for instance, a response to "QTH?" (What is your location?) might be "QTH NO" if no fixed position is available. This avoids ambiguity in low-visibility conditions, where partial signals could mislead. Chaining protocols enable combining multiple Q codes for compound replies, appending complementary details without separate transmissions; an example is "QSY 14200 QTH New York," where "QSY 14200" (change to 14200 kHz) is followed by "QTH New York" (my location is ) to simultaneously report a frequency shift and updated . Such sequences must follow the of the codes for logical . Overall, these protocols emphasize brevity, reducing airtime in adverse signal environments like high or , where each character transmitted impacts reliability. Q codes thus facilitate cross-lingual, service-agnostic exchanges by minimizing words to essential signals.

Applications by Communication Service

Maritime Mobile Service

In the Maritime Mobile Service, Q codes serve as standardized operating signals for radiotelegraph communications between ships and shore stations or among vessels, enabling concise transmission of procedural, navigational, and safety-related information across language barriers. Originating in from a British Post Office list for commercial maritime , these codes were formalized internationally at the Second International Radiotelegraph Convention in in , where a set of 45 Q codes was adopted to streamline ship-to-shore and ship-to-ship exchanges. The QOA–QQZ range was specifically allocated for maritime use by the (ITU), supporting efficient operations in transmissions. A primary application of Q codes in this service involves distress signaling and queries, where brevity is critical during emergencies. For instance, QSP ("Will you to...?") is employed to request of distress messages to ensure broader , while navigation-related codes facilitate position reporting and inquiries to aid safe passage. In operational contexts like formations during wartime or routine transits, QTG ("Will you to...?") allows vessels to designate intermediaries for message forwarding, enhancing coordination without lengthy plain-language exchanges. These uses underscore the codes' role in maintaining clear, rapid communication in high-stakes environments. Q codes were integrated with the (INTERCO), a visual and radiotelegraph system for safety and navigation, with select maritime Q codes aligning directly with INTERCO flags or signals for seamless interoperability between radio and flag-based methods; this synergy became a requirement for international vessels in the early under ITU regulations. However, as voice radiotelephony proliferated post-World War II and digital systems emerged, Q codes—tied to —were progressively phased out for commercial maritime operations, culminating in the 1999 implementation of the Global Maritime Distress and Safety System (GMDSS), which eliminated the Morse requirement for ships over 300 gross tons. Today, residual applications of Q codes persist in maritime mobile operations, where licensed radio operators aboard recreational vessels employ them during contacts for brevity and tradition, particularly in remote or where voice may be impractical. This continued use reflects the codes' enduring utility in non-commercial, hobbyist contexts despite their diminished role in professional shipping.

Aeronautical Service

Q codes play a vital role in aeronautical communications, particularly for air-ground and air-air interactions, where they facilitate concise transmission of critical information during flight operations. The (ICAO) standardized aeronautical Q codes in 1949 as part of 10 to the , aiming to enhance international flight safety through uniform radiotelegraph and radiotelephone procedures. These codes, designated in the QAA–QNZ series, were originally allocated by the (ITU) during the 1947 to support aviation-specific needs, such as settings essential for safe navigation. For instance, QNE refers to the standard of 1013.25 used above transition altitudes, ensuring consistent readings among aircraft in (IFR) environments. In and procedures, Q codes enable pilots to report and query vital environmental and situational data succinctly. Codes like QFT are employed to describe ice formation observations, specifying position, type (e.g., or ), accretion rate, and affected altitudes, which is crucial for avoiding hazardous during flight. Similarly, in emergencies, QHH signals an impending , prompting immediate responses, while QUG indicates a forced alightment, integrating seamlessly into distress protocols to prioritize . These applications underscore the codes' utility in high-stakes scenarios, where brevity prevents communication overload. Despite the dominance of GPS and modern digital systems by 2025, Q codes retain relevance in (VFR) and IFR clearances, particularly for settings like QNH (local sea-level pressure) and QFE (aerodrome-level pressure), which ensure accurate altitude awareness and terrain avoidance. Their persistence stems from the need for standardized, language-independent phrasing in diverse international . Historically, Q codes originated in era for efficient but transitioned to voice communications post-World War II, evolving into phonetic abbreviations (e.g., "QNH" pronounced as individual letters) to maintain clarity amid increasing radiotelephony adoption. This adaptation allowed their integration into contemporary aviation phraseology without disrupting established safety norms.

Amateur Radio Service

In the amateur radio service, Q codes were rapidly adopted following their international establishment at the Second International Radiotelegraph Convention in in 1912, providing a concise method for radiotelegraph communication amid the growing hobbyist community. The (ARRL), founded in 1914, integrated Q codes into its early operations for long-distance () contacts and emerging contests, recognizing their efficiency in exchanges where brevity was essential. By 1915, ARRL named its official publication QST after the Q code meaning "general call to all stations," underscoring their foundational role in amateur practices. Common operational uses of Q codes in emphasize streamlined communication during contacts. For instance, QSO denotes an ongoing or completed contact, QRZ? inquires "who is calling me?" to identify stations in busy frequencies, and QRM signals man-made interference affecting reception, allowing operators to adjust accordingly. These codes are particularly prevalent in (CW) modes for and contests, where they reduce transmission time and enable multilingual interactions without full sentences. Q codes also inform etiquette in organized amateur activities, such as nets and communications. In nets, ARRL-introduced QN signals from the late —extensions like QNC ("all net stations copy")—guide control operators in managing check-ins and message relays, promoting orderly and efficient proceedings. For operations under the (ARES), Q codes support procedural discipline in CW nets during disasters, ensuring rapid status reports and coordination while adhering to formal protocols that prioritize clarity over casual abbreviations in voice modes. Their relevance persists in digital modes, where Q codes' legacy endures in logging and terminology. In protocols like , operators record "QSOs" to confirm contacts, maintaining the code's conceptual framework for weak-signal exchanges despite the absence of traditional transmission.

Other Services

In radio communications beyond , Q codes provide standardized brevity for tactical operations among Allied forces. For instance, QTC denotes the number of messages or telegrams to be transmitted, facilitating efficient traffic handling in nets. NATO's Allied Communications Publication 131(F) authorizes Q codes (QAA–QUZ) for use between and civil stations, covering operational queries like readiness (QRV) and frequency changes (QSY), as well as technical assessments such as signal strength (QSA) and interference (QRM). These codes enhance clarity in and voice transmissions, reducing transmission time and detection risks. In services, Q codes support signal reporting in specialized operations like stations. The code QSA, assessing signal strength on a 1–5 scale (1: scarcely perceptible; 5: very strong), enables receivers to evaluate conditions during precise time transmissions. This usage aligns with international standards for radiotelegraphy, ensuring reliable reception of time signals critical for and . Q codes were historically employed in fixed radio services for point-to-point communications but have become obsolete with the evolution to digital systems. The (ICAO) removed specific Q code provisions from its documentation, such as in the 1999 edition of Doc 8400, reflecting a broader decline in Morse-based fixed service operations. Modern applications in satellite communications remain rare, primarily limited to legacy Morse protocols in professional and auxiliary systems where brevity is essential, such as reporting Doppler-induced frequency variations. Post-2000 integrations with have further marginalized Q codes in favor of protocol-specific abbreviations.

Specific Code Listings

Codes for Maritime Use (QOA–QQZ)

The Q codes designated for the Maritime Mobile Service span the range QOA to QQZ and are standardized in Recommendation M.1172 for use in radiocommunications involving ships, coast stations, and related entities. These codes serve as questions, replies, or indicators to streamline exchanges on topics such as communication capabilities, position reporting, weather conditions, distress signals, and operational procedures. They can be modified for affirmative ("C") or negative ("NO") responses and are typically followed by a when used interrogatively. An asterisk (*) denotes codes with meanings akin to those in the . While the full set encompasses over 100 codes, they are functionally grouped, with examples provided below to illustrate key applications; the complete enumeration is detailed in the ITU recommendation. Following the 1960 and subsequent updates, including the 1974 SOLAS adoption of GMDSS, reliance on code-based Q signals has diminished in favor of digital systems, leading to deprecation of some legacy procedures, though the codes remain valid for compatible operations. QO codes focus on vessel location, course, speed, and navigational intent, aiding in collision avoidance and coordination. For instance, QTH asks "What is your position?" with the reply providing coordinates in latitude and longitude (e.g., "Position is 40° N 30° W"). QTI* inquires about the true course, replied as degrees (e.g., "Course is 270°"), while QTJ* seeks speed, answered in knots or km/h (e.g., "Speed is 15 knots"). QRD queries destination and origin, with a reply like "Bound for New York from Southampton." These codes support real-time tracking, as in QRE for estimated time of arrival (e.g., "ETA at Lisbon is 1200 UTC"). Other examples include QRB for approximate distance (e.g., "Distance is 50 nautical miles") and QSH for direction-finding homing (e.g., "I am able to home on your station"). Deprecated post-SOLAS elements include older frequency-specific queries like QOA ("Can you communicate by radiotelegraphy on 500 kHz?"), now largely obsolete due to band reallocations.

Weather Reporting (QP Codes)

QP codes enable concise transmission of meteorological data essential for safe . QPU requests ice accretion details, replied with thickness and location (e.g., "Ice accretion 2 cm on "). QPV asks for sea ice information, such as type and (e.g., "Pack ice 10 miles ahead"). QPZ inquires about floating bergs, with replies specifying numbers and bearings (e.g., "3 bergs, bearing 045°"). These facilitate broadcast warnings, as in QUF for surface and force (e.g., " 220° at 25 knots"). Historical adjustments post-1960s SOLAS emphasized integration with automated systems, reducing manual Q code use for routine reports. Distress-related QR codes prioritize emergency coordination and search-and- (SAR) efforts. QRU signals "Have you anything for me?" in distress contexts, often replied negatively to clear channels. QSF* asks if has been effected, with an affirmative reply detailing casualties (e.g., "Rescue effected, proceeding to base with 5 injured"). QTD* queries recovered items in SAR, replied as "Survivors from vessel ABC recovered." QRV confirms readiness for emergency operations (e.g., "I am ready"). Examples include QOJ for listening on emergency frequencies (e.g., "Listen on 121.5 MHz") and QOK for received beacon signals (e.g., "Received on 406 MHz"). Post-SOLAS , codes like these were adapted for GMDSS integration, with some Morse-only variants deprecated as (DSC) became mandatory for distress alerts.
CategoryExample CodeQuestionReply/IndicatorUsage Context
CommunicationQOCCan you communicate by radiotelephony (channel 16, 156.80 MHz)?I can communicate by radiotelephony (channel 16, 156.80 MHz).Initial contact on VHF safety channel.
Signal QualityQSAWhat is the strength of my signals?The strength of your signals is 5 (loud).Assessing during position reports.
SAR/DistressQSE*What is the estimated drift of the survival craft?The estimated drift is 2 knots eastward.Coordinating drift in lifeboat scenarios.
WeatherQUB*Can you give me information concerning , height of , and at … station? 5 km, 1000 ft, rain.Low- navigation aid.
Up to QQZ, additional codes cover (e.g., QOL for MMSI numbers) and operational queries (e.g., QQZ: "Shall I send my position by …?"), ensuring comprehensive .

Codes for Aeronautical Use (QAA–QNZ)

The Q codes in the range QAA to QNZ are a standardized set of three-letter codes allocated by the (ICAO) for use in aeronautical communications, particularly in radiotelegraphy and radiotelephony within contexts. These codes facilitate efficient and unambiguous exchange of information between pilots and air traffic controllers, covering a variety of operational needs. The range begins with QAA, such as "What is your heading?" and extends to QNZ, with notable examples including QDM (true course to a station) and QNH ( to indicate elevation above mean ). The codes are organized into functional categories that reflect their practical application in . Navigation-related codes, such as those in the QA to QC range, assist with direction and positioning, exemplified by QAB ("What is your heading?"). Altimetry codes, spanning QNE to QNH, provide critical for altitude , with QNH being widely used to set altimeters for at a specific airfield. Communication-focused codes, such as those from QTA to QTZ, enhance operational coordination, ensuring clarity in . In 2025, the ICAO updated its procedures in Document 4444 to integrate Q codes for operations, reflecting the growing role of unmanned aerial vehicles in management. These revisions expand the applicability of certain codes, such as those related to and communication, to accommodate drone-specific requirements while maintaining with traditional aeronautical use. The updates ensure that Q codes remain a vital tool in an evolving landscape.

Codes for General Use (QRA–QUZ)

The QRA–QUZ series of Q codes is designated by the (ITU) for universal application in all radiocommunication services, enabling standardized, concise exchanges on topics such as station details, signal quality, adjustments, and position reporting. These codes originated in the early for radiotelegraphy but have been widely adapted for radiotelephony across services, including , where they are pronounced as abbreviations (e.g., "QSL" as "cue ess el") to confirm receipt or request acknowledgments without full sentences. A key cross-service example is QRM, used universally to query or report levels in any mode, with responses scaled from nil to extreme. Similarly, QRV indicates operational readiness, QTH reports , and QSL verifies message receipt, facilitating efficient communication in diverse contexts like operations or routine contacts. When used as questions, Q codes end with a query mark in telegraphy; in telephony, the interrogative sense is implied by context or intonation. Responses provide affirmative advice, often with numerical scales (e.g., 1–5 for signal strength) or insertable details like frequencies or times in UTC. Some codes marked with an asterisk (*) relate to distress or search-and-rescue scenarios applicable across services. The full enumeration, drawn from ITU standards, is presented below for reference.
CodeQuestionAnswer/Advice
QRAWhat is the name of your vessel (or station)?The name of my vessel (or station) is ...
QRBHow far approximately are you from my station?The approximate distance between our stations is ... nautical miles (or km).
QRCBy what private enterprise (or state administration) are the accounts for charges for your station settled?The accounts for charges of my station are settled by the private enterprise ... (or state administration).
QRDWhere are you bound for and where are you from?I am bound for ... from ...
QREWhat is your estimated time of arrival at ... (or over ...) (place)?My estimated time of arrival at ... (or over ...) (place) is ... hours.
QRFAre you returning to ... (place)?I am returning to ... (place). OR Return to ... (place).
QRGWill you tell me my exact frequency (or that of ...)?Your exact frequency (or that of ...) is ... kHz (or MHz).
QRHDoes my frequency vary?Your frequency varies.
QRIHow is the tone of my transmission?The tone of your transmission is ... (1. good, 2. variable, 3. bad).
QRJHow many radiotelephone calls have you to book?I have ... radiotelephone calls to book.
QRKWhat is the intelligibility of my signals (or those of ...)?The intelligibility of your signals (or those of ...) is ... (1. bad, 2. poor, 3. fair, 4. good, 5. excellent).
QRLAre you busy?I am busy (or I am busy with ...). Please do not interfere.
QRMAre you being interfered with? OR Is my transmission being interfered with?I am being interfered with. OR Your transmission is being interfered with ... (1. nil, 2. slightly, 3. moderately, 4. severely, 5. extremely).
QRNAre you troubled by static?I am troubled by static ... (1. nil, 2. slightly, 3. moderately, 4. severely, 5. extremely).
QROShall I increase transmitter power?Increase transmitter power.
QRPShall I decrease transmitter power?Decrease transmitter power.
QRQShall I send faster?Send faster (... words per minute).
QRRAre you ready for automatic operation?I am ready for automatic operation. Send at ... words per minute.
QRSShall I send more slowly?Send more slowly (... words per minute).
QRTShall I stop sending?Stop sending.
QRUHave you anything for me?I have nothing for you.
QRVAre you ready?I am ready.
QRWShall I inform ... that you are calling him on ... kHz (or MHz)?Please inform ... that I am calling him on ... kHz (or MHz).
QRXWhen will you call me again?I will call you again at ... hours (on ... kHz (or MHz)).
QRYWhat is my turn? (Relates to communication).Your turn is Number ... (or according to any other indication). (Relates to communication).
QRZWho is calling me?You are being called by ... (on ... kHz (or MHz)).
QSAWhat is the strength of my signals (or those of ...)?The strength of your signals (or those of ...) is ... (1. scarcely perceptible, 2. weak, 3. fairly good, 4. good, 5. very good).
QSBAre my signals fading?Your signals are fading.
QSCAre you a low traffic ship station?I am a low traffic ship station.
QSDAre my signals mutilated?Your signals are mutilated.
QSE*What is the estimated drift of the survival craft?The estimated drift of the survival craft is ... (figures and units).
QSF*Have you effected rescue?I have effected rescue and am proceeding to ... base (with ... persons injured requiring ambulance).
QSGShall I send ... telegrams at a time?Send ... telegrams at a time.
QSHAre you able to home with your direction-finding equipment?I am able to home with my direction-finding equipment (on ...).
QSII have been unable to break in on your transmission.Will you inform ... that I have been unable to break in on his transmission (on ... kHz (or MHz)).
QSJWhat is the charge to be collected to ... including your internal charge?The charge to be collected to ... including my internal charge is ... francs.
QSKCan you hear me between your signals and if so may I break in on your transmission?I can hear you between my signals; break in on my transmission.
QSLCan you acknowledge receipt?I am acknowledging receipt.
QSMShall I repeat the last telegram which I sent you?Repeat the last telegram which you sent me (or telegram(s) number(s) ...).
QSNDid you hear me on ... kHz (or MHz)?I did hear you on ... kHz (or MHz).
QSOCan you communicate with ... direct (or by relay)?I can communicate with ... direct (or by relay through ...).
QSPWill you relay to ... free of charge?I will relay to ... free of charge.
QSQHave you a doctor on board (or is ... on board)?I have a doctor on board (or ... is on board).
QSRShall I repeat the call on the calling frequency?Repeat your call on the calling frequency; did not hear you (or have interference).
QSSWhat working frequency will you use?I will use the working frequency ... kHz (or MHz).
QSUShall I send or reply on this frequency (or on ... kHz (or MHz)) (with emissions of class ...)?Send or reply on this frequency (or on ... kHz (or MHz)) (with emissions of class ...).
QSVShall I send a series of Vs for adjustment on this frequency?Send a series of Vs for adjustment on this frequency (or on ... kHz (or MHz)).
QSWWill you send on this frequency (or on ... kHz (or MHz)) (with emissions of class ...)?I am going to send on this frequency (or on ... kHz (or MHz)) (with emissions of class ...).
QSXWill you listen to ... on ... kHz (or MHz)?I am listening to ... on ... kHz (or MHz).
QSYShall I change to transmission on another frequency?Change to transmission on another frequency (or on ... kHz (or MHz)).
QSZShall I send each word or group more than once?Send each word or group twice (or ... times).
QTAShall I cancel telegram (or message) number ...?Cancel telegram (or message) number ...
QTBDo you agree with my counting of words?I do not agree with your counting of words; I will repeat the first letter or digit of each word or group.
QTCHow many telegrams have you to send?I have ... telegrams for you (or for ...).
QTD*What has the rescue vessel or rescue aircraft recovered?... (identification) has recovered ... (1. ... survivors, 2. wreckage, 3. ... bodies).
QTEWhat is my TRUE bearing from you? / What is my TRUE bearing from ... (call sign)? / What is the TRUE bearing of ... (call sign) from ... (call sign)?Your TRUE bearing from me is ... degrees at ... hours. / Your TRUE bearing from ... (call sign) was ... degrees at ... hours. / The TRUE bearing of ... (call sign) from ... (call sign) was ... degrees at ... hours.
QTFWill you give me the position of my station according to the bearings taken by the direction-finding stations which you control?The position of your station according to the bearings taken by the D/F stations which I control was ... latitude, ... longitude (or other indication of position), class ... at ... hours.
QTGWill you send two dashes of ten seconds each followed by your call sign (repeated ... times) (on ... kHz (or MHz))? / Will you request ... to send two dashes of ten seconds followed by his call sign (repeated ... times) on ... kHz (or MHz)?I am going to send two dashes of ten seconds each followed by my call sign (repeated ... times) (on ... kHz (or MHz)). / I have requested ... to send two dashes of ten seconds followed by his call sign (repeated ... times) on ... kHz (or MHz).
QTHWhat is your position in latitude and longitude (or according to any other indication)?My position is ... latitude, ... longitude (or according to any other indication).
QTIWhat is your TRUE course?My TRUE course is ... degrees.
QTJ*What is your speed?My speed is ... knots (or ... kilometres per hour or ... statute miles per hour).
QTK*What is the speed of your aircraft in relation to the surface of the Earth?The speed of my aircraft in relation to the surface of the Earth is ... knots (or ... kilometres per hour or ... statute miles per hour).
QTL*What is your TRUE heading?My TRUE heading is ... degrees.
QTM*What is your MAGNETIC heading?My MAGNETIC heading is ... degrees.
QTNAt what time did you depart from ... (place)?I departed from ... (place) at ... hours.
QTOHave you left dock (or port)? / Are you airborne?I have left dock (or port). / I am airborne.
QTPAre you going to enter dock (or port)? / Are you going to alight (or land)?I am going to enter dock (or port). / I am going to alight (or land).
QTQCan you communicate with my station by means of the International Code of Signals (INTERCO)?I am going to communicate with your station by means of the International Code of Signals (INTERCO).
QTRWhat is the correct time?The correct time is ... hours.
QTSWill you send your call sign (and/or name) for ... seconds?I will send my call sign (and/or name) for ... seconds.
QTT-The identification signal which follows is superimposed on another transmission.
QTUWhat are the hours during which your station is open?My station is open from ... to ... hours.
QTVShall I stand guard for you on the frequency of ... kHz (or MHz) (from ... to ... hours)?Stand guard for me on the frequency of ... kHz (or MHz) (from ... to ... hours).
QTW*What is the condition of survivors?Survivors are in ... condition and urgently need ...
QTXWill you keep your station open for further communication with me until further notice (or until ... hours)?I will keep my station open for further communication with you until further notice (or until ... hours).
QTY*Are you proceeding to the position of incident and if so when do you expect to arrive?I am proceeding to the position of incident and expect to arrive at ... hours (on ... (date)).
QTZ*Are you continuing the search?I am continuing the search for ... (aircraft, ship, survival craft, survivors or wreckage).
QUAHave you news of ... (call sign)?Here is news of ... (call sign).
QUB*Can you give me in the following order information concerning: the direction in degrees TRUE and speed of the surface wind; visibility; present weather; and amount, type and height of base of cloud above surface elevation at ... (place of observation)?Here is the information requested: ... (The units used for speed and distances should be indicated.)
QUCWhat is the number (or other indication) of the last message you received from me (or from ... (call sign))?The number (or other indication) of the last message I received from you (or from ... (call sign)) is ...
QUDHave you received the urgency signal sent by ... (call sign of mobile station)?I have received the urgency signal sent by ... (call sign of mobile station) at ... hours.
QUECan you speak in ... (language), with interpreter if necessary; if so, on what frequencies?I can speak in ... (language) on ... kHz (or MHz).
QUFHave you received the distress signal sent by ... (call sign of mobile station)?I have received the distress signal sent by ... (call sign of mobile station) at ... hours.
QUGWill you be forced to alight (or land)?I am forced to alight (or land) immediately. / I shall be forced to alight (or land) at ... (position or place) at ... hours.
QUH*Will you give me the present barometric pressure at sea level?The present barometric pressure at sea level is ... (units).
QUIAre your navigation lights working?My navigation lights are working.
QUJWill you indicate the TRUE track to reach you (or ...)?The TRUE track to reach me (or ...) is ... degrees at ... hours.
QUKCan you tell me the condition of the sea observed at ... (place or coordinates)?The sea at ... (place or coordinates) is ...
QULCan you tell me the swell observed at ... (place or coordinates)?The swell at ... (place or coordinates) is ...
QUMMay I resume normal working?Normal working may be resumed.
QUNWill vessels in my immediate vicinity (or in the vicinity of ... latitude, ... longitude) please indicate their position, TRUE course and speed? OR Please indicate your position, TRUE course and speed?My position, TRUE course and speed are ...
QUOShall I search for ... (aircraft, ship, survival craft) in the vicinity of ... latitude, ... longitude (or according to any other indication)?Search for ... (aircraft, ship, survival craft) in the vicinity of ... latitude, ... longitude (or according to any other indication).
QUPWill you indicate your position by searchlight, black smoke trail, or pyrotechnic lights?My position is indicated by searchlight, black smoke trail, or pyrotechnic lights.
QUQShall I train my searchlight on a cloud to assist your landing?Train your searchlight on a cloud to assist my landing as described.
QURHave survivors received survival equipment, been picked up by rescue vessel, or reached by ground rescue party?Survivors have received survival equipment from ..., been picked up by rescue vessel, or reached by ground rescue party.
QUSHave you sighted survivors or wreckage? If so, in what position?Sighted ... (survivors in water, on rafts, or wreckage) in position ... latitude, ... longitude.
QUTIs position of incident marked?Position of incident is marked by ... (flame or smoke float, sea marker, dye, or other).
QUUShall I home ship or aircraft to my position?Home ship or aircraft ... (call sign) to my position by ... (transmitting call sign and dashes or TRUE track).
QUWAre you in the search area designated as ...?I am in the ... search area.
QUXDo you have any navigational warnings or gale warnings in force?I have the following navigational or gale warnings in force: ...
QUYIs position of survival craft marked?Position of survival craft marked at ... hours by ... (flame or smoke float, sea marker, dye, or other).
QUZMay I resume restricted working?Distress phase still in force; restricted working may be resumed.

Adaptations and Variations

Historical and Informal Variations

During , German radio operators adapted the international Q code system for their specific operational needs, incorporating unique codes distinct from Allied usage. For instance, the code QEP was added to indicate that a receiver's apparatus was not , facilitating troubleshooting in encrypted communications often paired with machines for secure messaging. This adaptation highlighted the flexibility of Q codes in military contexts, where synchronization errors could compromise signal integrity amid high-stakes transmissions. In the early 20th century, experimental Q codes emerged as part of the system's initial development, with the British General Post Office introducing abbreviations around 1909 to streamline commercial radiotelegraph traffic. These early variants, such as initial RA-RZ and SA-SF series, were tested and refined before international standardization at the 1912 London Radiotelegraph Convention. By the 1920s, subsequent revisions by the International Telecommunication Union (ITU) led to the obsolescence of certain codes; for example, X codes used in European military telegraphy (e.g., X34 for specific procedural signals) were discontinued in 1942 at the insistence of U.S. forces, who favored the Q system for interoperability. Similarly, Z codes for high-speed Morse operations (e.g., ZAA for acknowledgment in rapid transmissions) were phased out post-World War II as radioteletype (RTTY) and facsimile technologies supplanted manual Morse. Informal variations of Q codes have proliferated within communities, often extending beyond official definitions to serve as shorthand slang. The code QRM, formally denoting man-made interference, is commonly used colloquially to describe any operational annoyance, such as overlapping transmissions from other stations during a . Likewise, QSL, which officially confirms receipt of a , has evolved into a cultural staple through QSL cards—physical or digital postcards exchanged as proof of contact and prized as collectibles, particularly those from rare expeditions or historical operators. These cards, akin to philatelic items, are traded and valued for their artwork, rarity, and evidential role in awards programs. Since the 1980s, informal digital evolutions of Q codes have emerged alongside the rise of computer-assisted modes in , adapting the system for text-based communications in protocols like PSK31 and RTTY. Operators embed Q codes as abbreviations in digital streams to query conditions (e.g., QRN for noise levels) or confirm contacts, preserving brevity in automated exchanges where voice or is absent. This shift, accelerated by personal integration, has led to ad-hoc extensions in online ham forums and software interfaces, such as informal Q signals for reports, though these remain non-standardized outside core amateur practices.