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Call sign

A call sign is a unique alphanumeric identifier assigned to a radio transmitting station, consisting of 3 to 7 characters, to facilitate identification during voice or communications. These identifiers are regulated internationally by the (ITU) and nationally by bodies such as the (FCC) in the United States, ensuring distinct recognition for stations in broadcasting, , , , and contexts. In and , call signs are sequentially assigned based on geographic regions and operator classes, using prefixes like "" or "" in the U.S. to denote location and service type. For example, the FCC mandates that broadcast stations transmit their call signs at regular intervals to comply with identification requirements under 47 CFR regulations. In , aircraft call signs derive from nationality and registration marks standardized by the (ICAO), often incorporating the ITU-assigned radio call sign for air-ground and ground-ground communications. Maritime call signs, similarly rooted in ITU allocations, identify ships for Global Maritime Distress and Safety System (GMDSS) operations, including distress alerts via the (MMSI), and are required in international voyages under (IMO) guidelines. In military applications, particularly aviation, call signs often serve as operational nicknames for pilots and units, enhancing brevity and security in while obscuring identities from adversaries. Across these domains, call signs promote efficient spectrum use, regulatory compliance, and safety in global radio communications.

Fundamentals

Definition and Purpose

A call sign is a unique alphanumeric identifier assigned to a transmitting radio , ship, , or , serving as its primary means of identification during radio communications. These identifiers typically consist of 3 to 7 characters, including letters and numerals, and are designed to distinguish one or entity from another in shared spectrum environments. The structure often incorporates prefixes or suffixes that indicate the or the , such as the "W" prefix allocated to operators . The primary purposes of call signs are to ensure clear and unambiguous of transmitting entities, thereby preventing signal and enabling the tracing of unauthorized or harmful transmissions. They facilitate by allowing authorities to monitor compliance with allocations and operational rules, while also supporting responses through rapid location of distress signals or rescue coordination. For instance, in cases of , the call sign acts as a "passport" for the station, aiding regulators in identifying and resolving issues. Call signs are governed internationally by the (ITU) , particularly , which mandates that all transmissions be identifiable by call signs or equivalent means to prohibit false or misleading identifications. National administrations, such as the (FCC) in the United States, adapt these regulations by assigning specific call signs within ITU-allocated series and enforcing their use across services. Variations in format exist by application; for example, often use four-letter codes, while combine a three-letter ICAO aircraft operator designator with the registration number.

History and Evolution

The origins of call signs trace back to early 20th-century , where the need for unique station identification arose amid growing maritime radio use. The sinking of the RMS Titanic in April 1912 highlighted the chaos of unregulated wireless communications, prompting swift regulatory action. In response, the passed the , which empowered the Bureau of Navigation in the Department of Commerce to license radio stations and assign call signs to both ships and land stations, marking the first systematic allocation in the U.S. to prevent interference and ensure distress signals could be properly directed. Internationally, the 1906 Berlin International Radiotelegraph Conference laid foundational groundwork by establishing the use of three-letter call signs for ship and coastal radio stations to standardize recognition in transmissions. Global standardization advanced through the (ITU), originally formed as the International Telegraph Union in 1865 but evolving to encompass radio. The 1912 International Radiotelegraph Conference in established initial prefix allocations, assigning the "G" series to the for its stations, a practice that began implementation in the and persists today. In 1932, the Madrid conferences merged the International Telegraph Union and International Radiotelegraph Union into the modern ITU structure, redrafting regulations to unify telegraph, telephone, and radio principles, including coordinated call sign series for international harmony. Post-World War II, the 1947 Atlantic City International Radio Conference updated these frameworks in the Radio Regulations, refining call sign formations and identification protocols to accommodate expanded radio services while maintaining global interoperability. Technological evolution drove further adaptations in call sign usage. In the 1920s, as voice transmissions supplanted for , the U.S. shifted from sequential numeric assignments to prefix-based systems; by 1923, stations east of the received "W" prefixes, while those west got "K" prefixes, streamlining identification amid the broadcast boom. The 1970s saw expansions in , with the ITU allocating new prefixes to emerging nations post-decolonization, such as "3DA" for Swaziland in 1971 and "5H" for in 1973, reflecting geopolitical changes and increased hobbyist participation. By the 1990s, digital advancements introduced enhancements like the (MMSI), a nine-digit numeric code integrated into the Global Maritime Distress and Safety System (GMDSS), enabling automated for satellite and mobile communications in addition to traditional alphanumeric call signs.

Transportation Applications

Maritime Call Signs

are unique alphanumeric identifiers assigned to ships and other vessels to facilitate identification during radio communications in the maritime mobile service. These call signs are issued by national maritime authorities responsible for radio licensing within their jurisdictions, ensuring compliance with international standards. For instance, in the United States, the (FCC) assigns call signs to ship stations as part of the licensing process for vessels equipped with radio installations. Similarly, in the , handles the assignment of call signs and Maritime Mobile Service Identities (MMSIs) exclusively for UK-flagged ships, including those registered in the Isle of Man or . Internationally, the (ITU) allocates blocks of call sign series to member administrations, while the (IMO) recognizes these identifiers for global vessel recognition and safety protocols. The format of maritime call signs typically consists of four letters, derived from the ITU's Table of International Call Sign Series (Appendix 42 to the ), which designates specific blocks to countries or entities. For example, the prefix C6A through C6Z is allocated to , allowing call signs like C6AB for Bahamian-registered vessels. Commercial vessels generally use these standard alphanumeric formats, often linked to the vessel's MMSI—a nine-digit numeric identifier—for integration in digital systems. In contrast, may receive specialized call signs; for instance, U.S. ships are assigned call signs beginning with "N," such as NAAB, distinguishing them from merchant vessels starting with "W" or "K." These formats ensure unambiguous identification across , with the MMSI serving as a complementary digital equivalent in automated transmissions. In operational use, maritime call signs are essential for voice and digital communications, particularly in safety and distress scenarios. They must be announced at the beginning and end of transmissions to identify the station clearly. For distress calls, the international signal "," repeated three times, is followed by the vessel's name and call sign, also repeated three times, to alert rescuers; for example, a transmission might include " , this is [vessel name] [call sign] [call sign] [call sign]." In voice communications, call signs are spelled using the to avoid misunderstandings, such as pronouncing "C6AB" as "Charlie Six Alfa Bravo." This practice enhances clarity in congested frequencies or adverse conditions. Regulations governing stem from the International Convention for the Safety of Life at Sea (SOLAS), 1974, as amended, which mandates radio installations—including unique identification via call signs—on all passenger ships and cargo ships of 300 and above engaged on voyages. Chapter IV of SOLAS requires these vessels to carry equipment for transmitting and receiving distress alerts, with call signs integral to station identification. Since the adoption of the Automatic Identification System (AIS) in 1998 by the (mandatory for SOLAS vessels from 2002, with development tracing to 1999 standards), call signs have been integrated with AIS transponders, which broadcast MMSI-linked data including the call sign for real-time vessel tracking and collision avoidance. Historically, originated in the pre-GPS era to enable precise position reporting and coordination via radio, a practice critical during emergencies when visual or aids were unavailable. A notable example is the RMS Titanic's call sign MGY, used in its distress transmissions via ("CQD DE MGY"), which alerted nearby ships like the despite the tragedy's scale. This underscores the enduring role of call signs in safety, evolving from manual to modern digital integration while maintaining their core function of unique vessel identification.

Aviation Call Signs

Aviation call signs serve as unique identifiers for aircraft during registration, (ATC) communications, and operational coordination, ensuring clear identification in both visual and radio contexts. Governed by the (ICAO), these call signs align with standards in Annex 7, which specifies nationality and registration marks derived from (ITU) prefixes, and Annex 10, Volume II, which details voice communication procedures for aeronautical mobile services. National aviation authorities, such as the (FAA) in the United States, issue these marks to registered aircraft, with the state of registry responsible for uniqueness and compliance. For instance, the FAA assigns N-numbers consisting of the letter "N" followed by 1 to 5 numerals or letters (e.g., N123AB), excluding formats starting with zero or resembling distress signals, to denote U.S.-registered civil aircraft. These registration marks form the foundation for radio telephony and must be prominently displayed on the aircraft's exterior, with minimum heights of 50 cm on wings for heavier-than-air craft and 30 cm on fuselage or tail surfaces. In operational use, aviation call signs facilitate ATC interactions primarily via very high frequency (VHF) radio, where pilots and controllers exchange instructions for safe navigation. ICAO Annex 10 mandates the use of the phonetic alphabet for spelling call signs during initial contact, with full recitation required to avoid ambiguity; abbreviations are permitted only after mutual acknowledgment. There are three primary types: Type A (pure registration mark, e.g., "Delta Charlie Echo" for DCDE, often prefixed with aircraft type like "Cessna DCDE"); Type B (telephony designator plus last four registration characters, e.g., "United ABCD"); and Type C (telephony designator plus flight identification number, e.g., "Speedbird One Two Three" for British Airways flight BA123, without abbreviation). Commercial operators obtain ICAO telephony designators (three-letter codes) and associated call signs through national authorities like the FAA, which coordinates with ICAO to prevent conflicts. These operational call signs, distinct from registration marks, enhance efficiency in high-traffic environments by linking to flight plans. Complementing call signs, squawk codes—four-digit transponder assignments (e.g., 1200 for VFR flights)—provide secondary radar identification but do not replace verbal call sign usage in voice procedures. Military aviation employs specialized call sign formats to support tactical operations, often deviating from civil standards while adhering to ICAO frameworks for international interoperability. Examples include mission-oriented designations like "Tanker One Two Three" for aerial refueling aircraft or squadron-specific codes (e.g., "Rogue One" for fighter formations), assigned by national defense authorities and notified to ICAO for cross-border flights. The FAA may authorize U.S. special telephony call signs for military or governmental operations of limited duration, ensuring they do not conflict with civil assignments. Temporary or event-specific call signs are also issued for non-routine activities, such as airshow flyovers or commemorative flights, where operators request unique identifiers from the FAA to indicate special ATC handling; for example, a formation team might use a collective callsign like "Thunderbirds One" during demonstrations. In crisis scenarios, call signs have proven vital for tracking; during the September 11, 2001, attacks, ATC used identifiers like "American Eleven" and "United One Seven Five" to monitor hijacked flights, enabling rapid coordination despite communication challenges.

Spaceflight Call Signs

In spaceflight, call signs serve as unique identifiers for spacecraft, satellites, and missions during radio communications, facilitating coordination between ground stations, control centers, and orbital or deep-space assets. These identifiers are assigned by space agencies such as and the (ESA), often in collaboration with regulatory bodies like the (ITU) to ensure global interoperability and avoid interference. For instance, allocates blocks of call signs to its centers and the (JPL) through the (FCC) via its National Spectrum Program Manager, while ESA designates mission-specific call signs, such as "" for the TMA-1 flight carrying ESA's first resident crew member. Call sign formats in spaceflight vary by mission type and purpose. Crewed missions typically use evocative, mission-specific names for spacecraft modules, such as "Columbia" for the Apollo 11 command module, which allowed ground control to address it distinctly during lunar operations. Satellites, particularly those in the amateur radio domain, employ telemetry identifiers like the OSCAR (Orbiting Satellite Carrying Amateur Radio) series, where designations such as AO-91 (AMSAT-OSCAR 91) function as call signs for transponder and beacon signals. The ITU Radio Regulations recommend that space service call signs consist of two characters followed by two or three digits to standardize identification across international operations. Operationally, spaceflight call signs enable voice and data communications from ground stations to spacecraft using frequency bands like S-band (2-4 GHz) for NASA's crewed missions and UHF (300 MHz-3 GHz) for telemetry and tracking in . This protocol originated with NASA's in the early 1960s, where capsules like "Freedom 7" and "Friendship 7" used numerical suffixes to denote the original seven astronauts, establishing a tradition for clear, phonetic addressing during ascent, orbit, and reentry phases. In modern missions, such as those to the (ISS), the call sign "Station" is used for routine ground-to-orbit voice links, supporting international crews and experiments. Regulations governing spaceflight call signs are outlined in ITU Radio Regulations Article 19, which mandates identification for all space stations to prevent interference, and extend to amateur satellites coordinated by the (IARU) for frequency allocations. For deep-space missions, the (COSPAR) assigns international designators, such as sequential alphanumeric IDs (e.g., 1961-001A), to uniquely identify probes and ensure traceability in interplanetary communications. These frameworks support both professional and amateur operations, with the latter relying on IARU-coordinated call signs for satellites like AO-91. Notable milestones highlight the evolution of spaceflight call signs. The Soviet Union's , launched in 1957, transmitted simple beep signals on 20 MHz and 40 MHz frequencies without a formal call sign, yet its rhythmic pulses served as an identifiable beacon detectable by global radio enthusiasts, marking the first artificial satellite's radio presence. The ISS exemplifies contemporary use, with "Station" facilitating daily operations since 1998, while integrations like NA1SS enable educational contacts. Amateur satellites continue this legacy, as seen with AO-91, launched in 2017, which uses its designation for voice repeater and telemetry functions in the 145 MHz band.

Communication Applications

Broadcasting Call Signs

Broadcasting call signs are unique alphanumeric identifiers assigned by national regulatory authorities to radio and television stations operating fixed-location transmitters, ensuring clear identification in public licensing and operations. In the United States, the manages the assignment through its Call Sign Reservation and Authorization System, issuing typically four-letter combinations such as WABC for New York's flagship AM station. International coordination for call signs in border areas occurs via bilateral agreements and ITU guidelines to prevent duplication and interference in cross-border transmissions. Call sign formats for broadcasting consist solely of letters, adhering to ITU-allocated series; in the US (ITU Region 2), prefixes are 'K' for stations west of the Mississippi River and 'W' for those east, a division originating from 1912 Bureau of Navigation regulations to organize early wireless assignments. FM radio and television stations employ the same base call sign formats as AM stations, with optional suffixes like -FM or -TV appended for clarity, as specified in FCC procedures for broadcast licensing. Operationally, broadcasting call signs uniquely identify stations in daily program logs, FCC compliance filings, and regulatory reports. In the , stations must announce their call signs on-air at the start and end of each broadcast day, as well as hourly—positioned as close to the hour as feasible without interrupting programming—to inform listeners of the station's identity and location. These requirements stem from the , which established the FCC and empowered it to regulate radio communications, including the mandatory assignment and use of call signs for licensed broadcasters. further govern Region 2 allocations, reserving specific series like , , and exclusively for the to harmonize international usage. Following the 2009 , when full-power stations ceased analog broadcasts, DTV operations continued using the same established call signs while adopting digital formats. Historically, broadcasting call signs evolved from three-letter formats in the early 1920s—when fewer than 1,000 stations existed—to four letters by 1923, expanding the available combinations amid rapid growth; legacy three-letter calls like WHO remain grandfathered. Internationally, the BBC's exemplifies early adoption, launching daily transmissions from on November 14, 1922, with its numeric-letter call marking the onset of structured public radio. Low-power stations below certain thresholds operate under FCC Part 15 rules as unlicensed devices and are exempt from call sign requirements, allowing community micro-broadcasting without formal assignment.

Amateur Radio Call Signs

Amateur radio call signs are unique identifiers assigned to licensed operators and stations for non-commercial communications, facilitating identification during transmissions worldwide. In the United States, the Federal Communications Commission (FCC) issues these call signs to amateur radio licensees through a sequential system, where each new license receives a unique identifier such as KD2ABC, denoting the operator's region and class. Internationally, the International Telecommunication Union (ITU) allocates prefixes to countries or territories, such as DL for Germany or W for parts of the United States, ensuring global recognition of the station's origin. The standard format consists of a one- or two-letter prefix followed by a numeral indicating the region or country, and a one- to three-letter or numeral suffix, resulting in patterns like 2x3 (e.g., AA1AB) or 1x2 (e.g., K1A). License classes influence available suffixes; for instance, in the US, Extra class operators can access shorter formats such as 1x1 calls (e.g., K4X) or 1x2, while Technician and General classes are limited to 2x3 formats unless upgrading. These formats adhere to ITU guidelines outlined in Appendix 42 of the Radio Regulations, which standardize series allocations to prevent conflicts. Operators must transmit their assigned call sign at short intervals during all emissions to identify the station legally, as mandated by ITU Radio Regulations Article 25, which governs amateur service operations. Club call signs are issued to amateur radio groups, allowing multiple members to operate under a shared identifier like W1AW for the American Radio Relay League (ARRL), provided a designated trustee manages the license. In some countries, including the US, vanity call signs—preferred personal identifiers matching the operator's initials or interests—can be requested through national authorities like the FCC for a fee of $35 per application, subject to availability and eligibility based on license class. The (IARU) supports call sign usage by coordinating band plans that promote efficient spectrum sharing among amateurs, indirectly aiding identification in crowded frequencies. Reciprocal licensing agreements, such as those under the European Conference of Postal and Telecommunications Administrations (CEPT) Recommendation T/R 61-01 adopted in 1985, allow licensed operators from participating countries to operate temporarily abroad using their home call signs without additional permits. The first in the were issued following the , which established federal licensing for private stations and standardized three-letter formats initially. Special event call signs, often in 1x1 formats like N4U, are temporarily assigned for commemorations, disasters, or public demonstrations, such as hurricane relief operations. In amateur satellite operations coordinated by AMSAT, ground station operators use their standard call signs during contacts, while satellites receive designations like (Orbiting Satellite Carrying Amateur Radio) for tracking, ensuring seamless identification in space communications.

Military Call Signs

Military call signs are assigned by individual branches of the armed forces to serve as unique identifiers for units, personnel, , or ships during , often integrating the for clarity in spelling out letters or numbers over radio. For example, the U.S. assigns voice call signs through service-specific instructions, which specify their use for establishing and maintaining communications among specific personnel and activities. These assignments are typically managed at the unit or theater level, with call signs drawn from standardized lists or briefed in operation orders to ensure uniqueness and brevity. To enhance security, especially in wartime, call signs are frequently rotated—often daily or at regular intervals—to prevent enemy interception and monitoring, a practice that originated in for tactical air control to obscure unit identities. Formats for call signs distinguish between procedural , such as "Eagle One" for a lead in a formation, and brevity codes designed to shorten messages without providing . Brevity codes, as outlined in multi-service publications like ATP 1-02.1, are standardized terms for efficient tactical exchanges, such as "DASH [number]" to indicate an 's relative to a reference point or "ANYFACE" for an unknown friendly command agency. In naval operations, procedural call signs like "Red Crown" were used for picket ships providing coverage and air control during the [Vietnam War](/page/Vietnam War), allowing quick identification in environments. These formats prioritize brevity and , with procedural signs often combining letters, numbers, or words (e.g., " Two-Zero-One" for a specific ), while brevity codes focus on condensing complex instructions in air-to-air or surface engagements. In operational contexts, military call signs facilitate unit identification during joint operations, enabling seamless coordination across branches and allies, as seen in U.S. Army usage during the where tactical signs like those of the helped mask locations and confuse adversaries over open radio nets. In secure networks, call signs may be encrypted or combined with procedural words from standards like ACP 125 to maintain operational security while directing actions such as . For instance, joint special operations under codes like "PRAIRIE FIRE" relied on assigned call signs to synchronize ground and air elements in high-risk extractions. Regulations governing call signs emphasize , with NATO's ACP 125 providing procedures that standardize call sign usage across allied forces, including types derived from ACP 135 for net control and identification. U.S. Department of Defense directives, such as those in joint publications and branch-specific instructions, mandate assignment protocols and security rotations to support tactical air control, a system refined since for directing close support missions. These standards ensure consistent application in multinational exercises and conflicts. Notable examples highlight their tactical significance: during the , the call sign "Bat 21" for a downed EB-66 triggered the largest, longest, and most complex search-and-rescue of the , involving multiple services and resulting in significant casualties to extract the sole survivor. In modern s, unmanned aerial vehicles (drones) employ call signs like "Reaper 11" for the MQ-9 to integrate with manned in joint strikes, maintaining the same procedural formats for . Non-combat brevity codes, such as "Thunderbird" for the U.S. Air Force demonstration team's F-16s, underscore their role in public displays while adhering to standardized assignment rules.

Additional Topics

Transmitters Not Requiring Call Signs

In the United States, the permits certain low-power transmitters to operate without individual licenses or assigned call signs under Part 15 of its rules, which covers intentional radiators (devices designed to emit radio frequency energy, such as routers and openers) and unintentional radiators (devices like computers that generate RF energy as a ). These exemptions apply to that adheres to strict limits to prevent with licensed services. Similarly, (CB) radios fall under FCC Part 95, Subpart D, allowing unlicensed operation without required identification or call signs, provided users follow power and frequency rules. The primary reasons for these exemptions are the devices' limited transmit power—often under 1 watt—resulting in short ranges (typically tens to hundreds of meters) and minimal risk of harmful interference to authorized radio services. This low-risk profile eliminates the need for formal licensing, call sign assignments, or international coordination through the (ITU), as operations remain localized and self-regulating. In the , equivalent provisions exist under the Radio Equipment Directive (RED) 2014/53/EU, which harmonizes standards for short-range devices (SRDs) like Bluetooth modules, enabling license-free use across member states if conformity is demonstrated through essential requirements and testing. Operationally, these transmitters face constraints such as mandatory acceptance of any received and prohibitions on modifications that could increase emissions; no periodic identification transmissions are required, unlike licensed services. Violations, including exceeding power limits or causing , can lead to actions like equipment seizure and fines up to $19,639 per violation or per day of continuing violation, with a maximum of $196,392 for any single act or failure to act (as of 2024) in the . The growth of (IoT) applications since the 2010s has amplified reliance on these exemptions, with connected devices surpassing 18 billion globally by 2024 and reaching 21.1 billion as of 2025, many utilizing Part 15-compliant technologies for wireless connectivity. Historically, such exemptions trace back to 1938, when the FCC first permitted unlicensed low-power devices under precursors to Part 15, with post- growth including devices like walkie-talkies, facilitating unlicensed personal and during and after .

Call Sign Databases and Callbooks

Call sign databases and callbooks serve as essential resources for verifying, researching, and managing radio station identifications across various domains, including , , and communications. Historically, these took the form of printed directories known as callbooks, which listed active stations, their operators, and contact details. The world's first callbook, titled the First Annual Official Wireless Blue Book of the Wireless Association of America, was published in 1909, compiling early amateur wireless stations and their call signs to facilitate communication among enthusiasts. In the United States, the (ARRL) began producing its own callbook in the early 1920s, with the inaugural edition of the Radio Amateur Call Book appearing around 1922; these annual publications listed thousands of operators until the print version ended in 1997. The transition from printed callbooks to digital databases accelerated in the late , driven by technological advancements and regulatory needs for efficient licensing management. In the 1990s, the U.S. (FCC) shifted to online systems, launching the Universal Licensing System (ULS) in 1999 as a centralized electronic platform for processing and searching licenses, including call sign assignments for amateur, commercial, and other services. Internationally, the (ITU) maintains the Table of International Call Sign Series (Appendix 42 to the Radio Regulations), an authoritative reference allocating prefix blocks to countries but not a searchable database of individual assignments; individual nations manage their own records. For , third-party platforms like , founded in 1992, evolved into comprehensive online databases, providing public lookups of over 1.5 million call signs worldwide by aggregating data from national regulators. In , the Deutscher Amateur-Radio-Club (DARC) supports access to the official Bundesnetzagentur (Federal Network Agency) call sign search engine, which lists licensed amateur stations and enables verification across . These resources are primarily used for verifying call signs during radio contacts—such as confirming QSL cards in amateur radio for awards and logs—and for historical research into past operators and station activities. Since the early 2000s, many databases have offered APIs for integration into logging software and mobile apps, with QRZ.com's XML Data Service, introduced around 2002, allowing programmatic access to call sign details for automated verification and mapping tools. This digital evolution has improved real-time accuracy but raised privacy concerns, particularly after the European Union's General Data Protection Regulation (GDPR) took effect in 2018; databases now often include opt-out options for personal information like addresses, balancing public access with data protection requirements. For instance, QRZ.com complies with GDPR by allowing users to restrict visibility of sensitive details while maintaining core call sign and licensing data.

References

  1. [1]
    FAQs categorized by Station identifications > Call Sign - ITU
    A Call Sign is a unique alphanumeric identity assigned to a transmitting radio station. It may contain from 3 up to 7 characters.Missing: FCC ICAO
  2. [2]
    Amateur Call Sign Systems | Federal Communications Commission
    Feb 27, 2023 · A unique call sign is assigned to each amateur station during the processing of its license applications. Each new call sign is assigned sequentially.Missing: definition | Show results with:definition
  3. [3]
    47 CFR 97.3 -- Definitions. - eCFR
    The call sign is selected by the FCC from an alphabetized list corresponding to the geographic region of the licensee's mailing address and operator class. The ...
  4. [4]
    Call Signs and Other Forms of Identifying Radio Transmissions - eCFR
    Each station using radio frequencies shall identify its transmissions according to the procedures prescribed by the rules governing the class of station to ...Missing: definition | Show results with:definition
  5. [5]
    [PDF] 1.3.0.12 ECCAIRS Aviation Data Definition Standard - ICAO
    Apr 29, 2013 · Aircraft call sign. Aircraft. Manual Entry. 54. The assigned International Telecommunications Union radio call sign of the aircraft. A group of.
  6. [6]
    Nationality Marks - ICAO
    ICAO nationality marks are standards for aircraft display, selected from ITU radio call signs, and published twice a year. States must notify ICAO of new marks.Missing: definition | Show results with:definition
  7. [7]
    Aviator Call Signs: The History & Naming Rituals - Department of War
    Jan 19, 2022 · These pilot nicknames can quickly identify an aircraft or individual, and they also help to confuse the enemy, who might be listening in on your ...
  8. [8]
    Table of International Call Sign Series (Appendix 42 to the RR) - ITU
    Table of International Call Sign Series (Appendix 42 to the RR) Series Allocated to 2AA - 2AZ 2BA - 2BZ 2CA - 2CZ 2DA - 2DZ 2EA - 2EZ 2FA - 2FZ 2GA -
  9. [9]
    Terrestrial Frequently Asked Questions (FAQ): Browse by categories
    Station identification code may be considered as a “passport” for a radio station. It serves for finding sources of interference, for organizing rescue ...
  10. [10]
    [PDF] ARTICLE 19 Identification of stations - ITU
    Stations can be identified by call signs, maritime mobile service identity, or other means, including name, location, or other distinguishing features.
  11. [11]
    [PDF] List of Call Signs and Numerical Identities of stations used by ... - ITU
    Oct 6, 2010 · Part III. – List of call signs of stations used in the maritime mobile service. Part IV. – List of numerical identities used in the maritime ...
  12. [12]
    ICAO Aircraft Company/Telephony/Three−Letter Designator and ...
    Chapter 3. ICAO Aircraft Company/Telephony/Three−Letter Designator and U.S. Special Telephony/Call Signs. Aircraft Company/Telephony/Three−Letter Designator ...
  13. [13]
    Radio Act of 1912 (1912) | The First Amendment Encyclopedia
    Jul 26, 2023 · The act provided for the licensing of radio operators, a separate frequency for distress calls, absolute priority for distress calls, and 24- ...
  14. [14]
    Titanic, Marconi's “Wireless Telegraphers” and the U. S. Radio Act of ...
    The Titanic disaster led to the U.S. Radio Act of 1912, which mandated 24-hour manning of wireless equipment and regulated wireless communication to improve ...
  15. [15]
    International Radiotelegraph Conference (Berlin, 1906) - ITU
    It was also decided that priority would be given to the SOS distress signal (...---...) and government licensing required to establish and operate ship stations ...Missing: call signs
  16. [16]
    United States Callsign Policies - Early Radio History
    The use of identifying radio callsigns actually had its origins in wire telegraphy, where each station and operator along a telegraph line was assigned a short ...
  17. [17]
    [PDF] The Storied History of the Ham Radio Call sign - W7VO
    The Atlantic City International Telecommunications Union (ITU) Conference of 1947 (the ITU had changed its name in 1932), reallocated some call sign blocks, and ...
  18. [18]
    International Telegraph Conference (Madrid, 1932) - ITU
    In 1932, in Madrid, a plenipotentiary Telegraph Conference and the International Radiotelegraph Conference met simultaneously and decided to merge into a ...
  19. [19]
    International Radio Conference (Atlantic City, 1947) - ITU
    Complete list of Radio Conferences. Outcomes. Radio Regulations and Additional Radio Regulations (Atlantic City, 1947), (English), download PDF PDF (acrobat).
  20. [20]
    K/W Call Letters in the United States - Early Radio History
    The United States federal government began licencing radio stations in late 1912, and from the beginning it has assigned call letters starting with K and W.
  21. [21]
    Call-Sign History - DX Info Centre
    Countries have often deviated from their official call-sign allocations. The prefixes shown here are for use by all classes of stations. The dates shown are ...
  22. [22]
    The evolution of maritime communications - SAFETY4SEA
    Sep 1, 2022 · The Digital selective calling. As part of the GMDSS, Digital Selective Calling (DSC) allowed for greater communication capabilities including ...
  23. [23]
    Ship Radio Stations Licensing - Federal Communications Commission
    Sep 15, 2023 · Licenses are needed for certain ships, like cargo ships over 300 gross tons, and ships traveling to foreign ports. File FCC Form 605 to obtain ...Global Maritime Distress and... · MMSI · Ship Radio Stations · Operations
  24. [24]
    Apply for or vary a maritime radio licence - Ofcom
    Jan 30, 2017 · You are able to apply for and issue this licence immediately online by logging into the Online Licensing System.
  25. [25]
    Maritime Mobile Service Identities - MMSI | Federal Communications ...
    Oct 4, 2022 · MMSIs are nine-digit numbers used to uniquely identify ships or coast radio stations, vital for emergency personnel, and transmitted over radio.Missing: history 1990s
  26. [26]
    [PDF] GMDSS Data Elements - uscg navcen
    Note: The first three digits of the MMSI are Maritime Identification Digits defined by Appendix 43 of the ITU Radio Regulations, identifying the country to ...<|control11|><|separator|>
  27. [27]
    PIONEERS' PAGE - ITU
    It was sent on 15 April 1912 by a ship in distress, which the second group of letters (MGY) specifically identified as “Titanic.” The tragic maiden voyage of ...
  28. [28]
    None
    ### Summary of ICAO Annex 7: Aircraft Nationality and Registration Marks
  29. [29]
    Aircraft Registration | Federal Aviation Administration
    Where do N-numbers come from? The U.S. received the "N" as its nationality designator under the International Air Navigation Convention, held in 1919. The ...
  30. [30]
    Aircraft Call Sign | SKYbrary Aviation Safety
    An aircraft call sign is a group of alphanumeric characters used to identify an aircraft in air-ground communications. There are three types of call signs.
  31. [31]
    How to Get an ICAO Call Sign/Telephony Designator - NBAA
    A traditional call sign consists of a written element, the company designator and a verbal element, the telephony designator. Eligible operators may request an ...
  32. [32]
    [PDF] Advisory Circular - Federal Aviation Administration
    Sep 10, 2018 · This Advisory Circular (AC) describes the Federal Aviation Administration (FAA) Air Traffic. Organization (A TO) requirements and procedures for ...
  33. [33]
    Appendix H. Call Signs - NODIS Library - NASA
    Sep 22, 2014 · Blocks of call signs are allotted to NASA Centers and JPL (an FFRDC) for assignment by the FCC through the NASA National Spectrum Program Manager.
  34. [34]
    ESA - Odissea - European Space Agency
    It is also the first flight of the TMA-class Soyuz spacecraft. MISSION STATISTICS. Mission name: Soyuz TMA-1. Call sign: Yenisey Number of crew members: 3
  35. [35]
    Apollo 11 Flight Journal - Day 5, part 2: Undocking and the Descent ...
    Oct 5, 2023 · It re-emerges as two separate spacecraft with their own call signs, Columbia and Eagle. They make one further lunar orbit, then the Eagle ...
  36. [36]
    AO-91 (Fox-1B) - AMSAT
    Apr 27, 2025 · AO-91 is the second of the Fox-1 generation of AMSAT-NA CubeSats. Due to battery deterioration, it is operating as a Carrier Operated Repeater, ...
  37. [37]
    [PDF] Space shuttle air-to-ground communication is - NASA.gov
    Space shuttle air-to-ground communication is transmitted on one of two designated S-band frequencies. Because the S-Band voice is digitized,.
  38. [38]
    Satellites | International Amateur Radio Union (IARU)
    Mar 11, 2025 · This section contains information about the upcoming IARU Satellite Frequency Coordination Panel meeting, latest news and information about ...
  39. [39]
    Assigning an identification to a satellite, revisited - The Space Review
    Jun 30, 2025 · COSPAR designators tell the sequential number of each launch, each year, and adds alphabetic character (or characters) to distinguish each ...
  40. [40]
    Sputnik - The Beep Heard Round the World.
    Oct 2, 2007 · With those faint beeps from that metal sphere called Sputnik, the Soviet Union was the first country ever to launch a satellite into space.
  41. [41]
    Contact the ISS - ARISS
    The following call signs are available for use on the ISS: Russian: RS0ISS ... Other call signs may come into use as the station and crew change. QSL Cards
  42. [42]
    [PDF] ARTICLE 25 Amateur services - ITU
    2) During the course of their transmissions, amateur stations shall transmit their call sign at short intervals. § 6 The provisions of Section I of this ...
  43. [43]
    Club Stations - Federal Communications Commission
    Aug 28, 2025 · A club station license allows members of an amateur radio club to have a station operating under a club call sign.
  44. [44]
    https://www.arrl.org/vanity-call-signs
  45. [45]
    Band Plans | International Amateur Radio Union (IARU)
    Sep 21, 2022 · The three IARU regional organizations develop band plans to offer guidance to radio amateurs on how the different operating interests and modes ...
  46. [46]
    ECC - Topics - Other spectrum topics - Radio Amateurs - CEPT.org
    Jan 27, 2025 · ITU Radio Regulations, Article 25.9A, encourages administrations to take necessary steps to allow amateur stations to prepare for and meet ...
  47. [47]
    History of the Ham Radio Callsign - eHam.net
    May 20, 2017 · The system between 1912 and 1927 worked on precedent, as the practices used by the major players was to use three-letter coast station calls, ...Missing: Bureau | Show results with:Bureau
  48. [48]
    Special Event Call Signs | Federal Communications Commission
    Oct 4, 2022 · The format of each call sign ("one-by-one") consists of a single letter prefix "K", "N" or "W", followed by a single digit numeral "0" through " ...
  49. [49]
    AMSAT Live OSCAR Satellite Status Page
    This web page was created to give a single global reference point for all users in the Amateur Satellite Service to show the most up-to-date status of all ...So-124 (hades-r) · Hades-icm (so-125) · RS-44 · AO-91 (Fox-1B)
  50. [50]
    The NATO phonetic alphabet – Alfa, Bravo, Charlie..., 20-Oct.
    Oct 20, 2016 · The NATO phonetic alphabet became effective in 1956 and just a few years later became the established universal phonetic alphabet.Missing: assignment | Show results with:assignment
  51. [51]
    [PDF] Air Force Instruction 33-217 Communications and Information Voice ...
    May 27, 1997 · Voice call signs are used to establish and maintain voice communications within the. Air Force. Specific personnel and activities of the ...
  52. [52]
    Military - GlobalSecurity.org
    2) ACP 125(D) Communications Instructions--Radiotelephone Procedures ACP 126 ... Joint Army-Navy-Air Force Publications (JANAP). JANAP 119(J) (CRD) Joint Voice ...<|separator|>
  53. [53]
    None
    Summary of each segment:
  54. [54]
    [PDF] download 3.2 MB pdf - Navy Radio
    Call signs are letters, letter-number com- binations, or one or more pronounceable words used principally to identify a communication activity. This is true in ...
  55. [55]
    PRAIRIE FIRE Mission - Air Force Museum
    PRAIRIE FIRE Mission. A top-secret joint special operations unit called the Military Assistance Command, Vietnam – Studies and Observation Group ...
  56. [56]
    [PDF] Communications Instructions Radiotelephone Procedures
    Nov 28, 2016 · The following diagrams demonstrate verbal callsigns that are used within examples throughout this publication. Examples of Radio Transmissions.
  57. [57]
    Rescue of Bat 21 - Air Force Museum
    Col. Hambleton was the only crewmember to safely eject after his EB-66 (call sign Bat 21) was hit by a surface-to-air missile.
  58. [58]
    11 Military Drone Names, Ranked - Task & Purpose
    May 10, 2017 · 11 Military Drone Names, Ranked · 1. Reaper · 2. Shadow · 3. Global Hawk · 4. Grey Eagle · 5. Sentinel · 6. Fire Scout · 7. Snowgoose · 8. Pioneer.
  59. [59]
    Military Radio Callsign List
    DAVLENIE HF callsign for Russian Air Force 708th Air Transport Regiment, 6958th Air Base, Taganrog ... IRON CROSS Tactical Air Controller, NAS Patuxent River MD
  60. [60]
    47 CFR Part 15 -- Radio Frequency Devices - eCFR
    This part sets out the regulations under which an intentional, unintentional, or incidental radiator may be operated without an individual license.
  61. [61]
    47 CFR Part 95 Subpart D -- CB Radio Service - eCFR
    A mobile and fixed two-way voice communication service for facilitating personal, business or voluntary public service activities.
  62. [62]
    Low Power Radio - General Information
    Jan 11, 2017 · Unlicensed operation on the AM and FM radio broadcast bands is permitted for some extremely low powered devices covered under Part 15 of the FCC's rules.Carrier Current and Campus... · Low Power FM (LPFM) Service...
  63. [63]
    Short Range Devices - ETSI
    As a general principle, a user is licence free to operate such equipment, some specific cases may require an individual licence. However, like all radio ...<|control11|><|separator|>
  64. [64]
    Uses of radio spectrum | Shaping Europe's digital future
    Right to use spectrum in licence-exempt frequency bands are granted to devices that meet certain technical conditions to share the spectrum. However, individual ...Missing: no | Show results with:no
  65. [65]
    Enforcement Actions | Federal Communications Commission
    September 15, 2025. Order. FCC Removes chase tech llc from Robocall Mitigation ... FCC Affirms $40,000 Fine for PIRATE Act Violations. September 10, 2025.
  66. [66]
    Number of connected IoT devices growing 14% to 21.1 billion globally
    Oct 28, 2025 · The number of connected IoT devices reached 18.5 billion in 2024, representing a 12% growth over 2023, according to IoT Analytics' ongoing ...Missing: FCC | Show results with:FCC
  67. [67]
    A Selective History of Part 15 of the FCC Rules: An Engineering ...
    Aug 1, 2025 · Part 15 of FCC rules, first mentioned in 1938, regulates low-power devices and is an important part of the FCC rules, allowing unlicensed ...
  68. [68]
    Radio Story - Callbook History - Jerry Proc
    The first edition of the callbook appeared some time around 1920 or 1922 until it was discontinued in 1997 by the publisher Watson-Guptil of New York. Watson- ...
  69. [69]
    Universal Licensing System - Federal Communications Commission
    Aug 26, 2021 · Consistent with Public Notice DA 20-361 released on March 31, 2020, all requests for confidential treatment associated with ULS filings may ...ULS Electronic Batch Filing · Routine Downtime Schedule · Wireless Services
  70. [70]
    About QRZ
    Jun 24, 2024 · QRZ was founded in 1992 by Fred Lloyd, AA7BQ as a spinoff of what was once called the Callsign Project, a cooperative effort designed to obtain and distribute ...
  71. [71]
    Visitors to DL - DARC
    You can apply for a permanent German Amateur Radio license with call sign. ... If you know his call sign, you can visit the callsign search engine of the BNetzA.
  72. [72]
    The QRZ XML Interface Specification
    This document describes the interface specification for access to QRZ's XML subscription data service. This service provides real-time access to information ...
  73. [73]
    QRZ.com and GDPR : r/amateurradio - Reddit
    Apr 27, 2022 · The general basics of GDPR are that anyone can store your data and use it. BUT they can only store it and use it with your permission and only ...Amateur Radio Clubs - protecting members' personal data, privacy ...GDPR and ham radio : r/amateurradio - RedditMore results from www.reddit.comMissing: impact | Show results with:impact