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A call sign (also a station identifier ) is used to identify a radio station according to the regulations of the International Telecommunication Union (ITU) . In the radio services in which a call sign is used, the call sign must be named in international radio communications in accordance with the radio service regulations according to the international spelling table specified there in Appendix 14 .


A callsign consists of a sequence of letters and numbers that are formed according to certain schemes. The first characters, the ITU prefix , are used to identify the nationality of the radio station. These prefixes are determined by the ITU and assigned to the states in one or more blocks . They usually consist of two characters, at least one of which is a letter. Some major countries use one-character prefixes and, in exceptional cases, three characters are used.

For better differentiation and easier handling during the allocation, the radio stations of the various radio services are allocated call signs according to certain schemes:

Call sign formation for various radio services (selection)
Radio service Possible callsigns
Fixed radio service NNA, NNA9, NNA99, NNA999
Mobile maritime service NNAA, NNAA9, NNAA99, NNA999, NNA9999
Mobile aeronautical service NNAAA, NAAAA, N9999 (other callsigns possible)
Land mobile service NA9999, NNA9999, NNAA9999
Amateur radio service NN9A, NN9NA, NN9NNA, NN9NNNA, A9A, A9NA, A9NNA, A9NNNA
(N = letter or number, A = letter, 9 = number). At least one of the first two characters is a letter; in most cases the digits 0 and 1 cannot follow a letter

Historical development of the prefixes

The historical development of the prefixes for the German-speaking countries is shown in the following table:

ITU prefixes in German states, Austria and Switzerland
country Prefixes Remarks
German Empire D. 1935 to 1945
Saarland 9S 1949 to 1957
German Democratic Republic DM-DT, Y2-Y9 DM-DT 1949 to 1979, Y from 1980 to 1990
Federal Republic of Germany DA-DR, Y2-Y9 Until 1979 only DA-DL. In 1979, the ITU assigned the call sign block DM-DR given by the GDR to the Federal Republic of Germany. The Y-prefixes were used in the Federal Republic for a transitional period until December 31, 1992, but are no longer used (an exception was 70 temporary Y8 competition callsigns for the WRTC radio sport world championship in July 2018).
Austria OE First amateur radio licenses after the Second World War from June 1954
Switzerland HB, HE The prefixes HB0 and HE0 are used by Liechtenstein . HB2 is awarded to contest stations , HB3 for the entry-level license and HB4 for amateur radio stations of the army and organizations close to the army. For the normal amateur radio license, callsigns with HB9 are assigned. Swiss ocean yachts receive callsigns starting with HBY.

The call signs are assigned accordingly by the national administrative authorities, taking into account the given prefixes. Not all options for call sign formation are used. In Germany, callsigns are issued by the Federal Network Agency for Electricity, Gas, Telecommunications, Post and Railways (BNetzA).

In the United States , television and radio stations traditionally use their call sign instead of their name to answer.

Call sign in the amateur radio service

In the United States, radio amateurs also use their callsigns for their license plates

Callsigns are generally transmitted regularly in the amateur radio service. The allocation of the call signs to the individual radio stations or license holders takes place according to certain schemes that take into account, for example, the license classes, the geographical location or the use of the radio station (for example as a club station or relay radio station).

Call signs in aviation

In aviation, a distinction is made between ground radio stations and air radio stations .

Call signs from ground stations

The call sign of a ground radio station is made up of a place name or the name of a ground radio station and one of the function names listed below.

Radio communications in English
CONTROL District control without radar
RADAR Air traffic control with radar
APPROACH Approach and departure control without radar
ARRIVAL Approach control with radar
DEPARTURE Departure control with radar
TOWER Airport control
GROUND Air traffic control on the tarmac
DELIVERY Transmission of route clearances
PRECISION Final approach control with precision radar
HOMER Bearing station
INFORMATION Flight information service (in Germany the DFS )
APRON Movement control on the apron
DISPATCH Transmission of flight operations reports from an airline
RADIO remaining radio station
Radio communication in German (partly specific to Germany)
TOWER Airport control
ROLL CONTROL Air traffic control on the tarmac
INFORMATION Flight information service
START or SCHOOL Aviation training
INFO Aerodrome information service provided by aerial supervisors or flight controllers
FOREFIELD Movement control on the apron
GLIDING Glider operations
RETURNERS Glider escort and return service
PURSUERS Free balloon escort and return service
COMPETITION Competitive events

Air station call signs

Cessna 172 with clearly visible callsign N61848 'N' in this case stands for the USA and '61848' is the registration symbol
Rescue helicopter Christoph 13 with call sign D-HZSG at the rear, 'D' stands for Germany, 'H' for helicopter and 'ZSG' the individual identification of the helicopter, the call sign 'Christoph 13' is only used in BOS and aeronautical radio, when the helicopter is in the air rescue service.

Air station call signs must be one of the following types:

Type a)
  1. Nationality and registration mark of the aircraft
  2. Name of the aircraft manufacturer, nationality and registration number of the aircraft
  3. Name of the aircraft type, nationality and registration number of the aircraft
Type b)
The designation † of the air carrier used in radiotelephony , followed by the four characters of the registration mark
Type c)
The designation † of the air carrier used in radiotelephony , followed by the flight number
Type d)
A call sign with a maximum of seven digits for military aircraft and for aircraft used for special public purposes.

The call signs of air stations may not be changed during the flight, unless the ground station has expressly assigned a different call sign to avoid confusion. The use of shortened callsigns is permitted under certain conditions.

The designation used in radiotelephony is mostly derived directly from the airline's name (e.g. " Delta " or " Lufthansa "), but sometimes a completely different word (e.g. "Cactus" in America West or later US Airways) ). These designations are given in the articles on the airlines in the respective info box under "callsigns" and in summary in the list of airlines .


  • The tower in Munich (ground radio station) is called in English as Munich Tower or in German Munich Tower according to the above scheme (place name function) .
  • An Austrian motor glider with the aircraft registration OE-9315 is called Oscar-Echo-Neun-Drei-Eins-Fünf (type a) 1.). Abbreviated callsign: Oscar-one-five or Oscar-three-one-five
  • A Lufthansa Boeing with the registration D-ABCD , which flies with the flight number LH-7810 , could be called Delta-Alpha-Bravo-Charlie-Delta ( Delta-Charlie-Delta for short ). However, type c), i.e. Lufthansa-Seven-Eight-One-Zero, is common for scheduled and charter flights .
  • Special call signs type d) are e.g. B.

Radio call signs in seafaring

Cap San Diego marine radio station , callsign DNAI is affixed to the device

In the mobile marine radio service, a distinction is made between coastal radio stations and marine radio stations .

Coast station call signs

For the use of Morse code , a coast station is or has been assigned a call sign, e.g. B. DAN for Norddeich Radio or DHS for Rügen Radio (until the end of 1979, from 1980 Y5M ). When using radiotelephony , coast stations are not called with a call sign but with their name. The name is made up of the place name and the word "radio" or z. B. "Lock". Likewise, in the global distress and safety system ( GMDSS ), a coast radio station is also clearly identified by its mobile maritime radio service number ( MMSI ).

Call signs from marine stations

Each marine radio station has a unique call sign, which is composed of several letters or a combination of letters and numbers. A callsign uniquely identifies a marine radio station; H. each callsign is only given once.

For ships registered in the shipping register, the distinguishing signal is also the call sign, e.g. B. DRAX for the Gorch Fock .

Marine radio stations can also be called with the name of the vehicle on which they are located. Likewise, in the global distress and safety radio system ( GMDSS ), a marine radio station is also clearly identified by its number of the mobile marine radio service ( MMSI ).

Callsign on the radio

"NewsTalkRadio 77" in New York. The callsign WABC is part of the logo. 77 stands for 770 kHz, i.e. medium wave
CBS Radio 1070 kHz Los Angeles. Display of the KNX call sign in the car radio

In North America and individual states in South and Central America, radio and television stations are designated by their call sign. In most European countries, the call signs that were originally mentioned on the radio stations disappeared early; in Germany they were never used.

In the USA, the mandatory use of callsigns goes back to the radio history of the country and from 1930 with the licensing by the Federal Communications Commission . At the beginning of the 20th century, the then International Telegraph Union (ITU) assigned the country codes "W", "K", "N" and "AA" to "AL" to the United States in several steps. While "A" and "N" are used for military and amateur radio services, US broadcasters get callsigns starting with "K" or "W" when licensed by the FCC. Broadcasters located west of the Mississippi receive callsigns beginning with the letter "K"; Transmitter east of the Mississippi with "W". This regulation was introduced in January 1923 and is still in force today. Broadcasters licensed very early received only three letters and did not fall under the "Mississippi Rule".

In the 1940s, the first VHF stations (with frequency modulation ) were added to the original US medium and shortwave stations . The addition "-FM" was added to the call sign , and television stations from the 1970s onwards were given the addition "-TV" . The prefix is an integral part of the callsign. The callsign is also always licensed to a specific frequency. That is why there are, for example, the stations "KCBS" ( San Francisco , medium wave), "KCBS-FM" ( Los Angeles ) on VHF and "KCBS-TV" (Los Angeles), each of which is an independent transmitter.

Radio stations in the USA are perceived even more strongly as "radio stations" with a fixed location than is usual in Europe, for example. It is mandatory that all broadcasters in the USA give their callsign and their location, the “legal ID”, on the hour.

See also

Web links

Individual evidence

  1. Federal Network Agency: Communication No. 220/2018. 2018, accessed March 5, 2020 .
  2. Michael Edward Smith: Re: WRTC and IARU. In: N1MM Logger Plus forum. July 12, 2018, accessed on March 5, 2020 (with photo of the list from the organizer).
  3. ^ ICAO Doc 9432, Manual of Radiotelephony
  4. FEDERAL COMMUNICATIONS COMMISSION - US Regulatory Commission, viewed on January 16, 2016 [1]  ( page no longer available , search in web archivesInfo: The link was automatically marked as defective. Please check the link according to the instructions and then remove this notice.@1@ 2Template: Dead Link /  
  5. FCC query on January 16, 2016 [2]
  6. FCC query on January 16, 2016 [3]
  7. FCC query on January 16, 2016 [4]
  8. Information from "How broadcasters in the USA got their" strange "names" from www.mycberradio, viewed on January 16, 2016 [5]