Callsign

Informal designations are also used for some services, especially broadcast radio, but strictly speaking these are not callsigns and there is no guarantee that they are unique. Tactical designators or identifiers (often called tactical callsigns) also fall into this category.

Each country has a set of alphabetic or numeric International Telecommunication Union-designated prefixes with which their callsigns must begin. For example:

• The U.S.A. uses the prefixes: W, K, N, and AAA to ALZ
• France uses the prefixes: F, TM
• Chad uses the prefix: TT
• Italy uses the prefix: I

Amateur radio callsigns

Amateur radio callsigns normally consist of a one or two character prefix, a number (which sometimes corresponds to a geographic area within the country) and a 1, 2, or 3 character suffix. The number following the prefix is normally a single number (0 to 9). Some prefixes, such as Djibouti's (J2), consist of a letter followed by a number. Hence, in the hypothetical Djibouti callsign, J29DBA, the prefix is "J2", the number is "9", and the suffix is "DBA". In the Italian callsign, IK1TZO, "IK" is the prefix, the number component is "1" and corresponds to the Piemonte region, and TZO is the suffix. Another example is WB3EBO. "WB" is the prefix, the number "3" most often indicates that the station is located in Delaware, Maryland, Pennsylvania, or the District of Columbia. The suffix is "EBO".

Broadcast callsigns

Broadcast stations in the U.S. and Canada are assigned three or four letter callsigns. Many of these, such as Baltimore television station WJZ, have long historical associations. Others are changed frequently as the station changes format. Many stations prefer not to use callsigns at all, since a slogan is more easily remembered by listeners filling in diaries for the Arbitron[?] Company's radio ratings. However, in the U.S., the Federal Communications Commission does require periodic identification using the formal callsign.

In the United States, the vast majority of stations east of the Mississippi River have callsigns beginning with "W". Exceptions include: KDKA (Pittsburgh), the first broadcasting station in the world, and KYW (Philadephia). Callsigns of US stations west of the Mississippi River generally begin with "K". Among the exceptions to this are WDAF (Kansas City) and WTAW (Bryan, Texas).

In Canada, stations of the Canadian Broadcasting Company tend to identify themselves as "CBC Radio One/Two" of a city, although they do have official three and four letter callsigns that usually begin with "CB" and "CF" through "CK". Commercial stations use a four-letter callsign.

In Europe and much of Asia, callsigns are normally not used for broadcast stations. Japan, South Korea and Taiwan are exceptions to this general rule.

Tactical designators

Police units in the United States tend to use a tactical designator consisting of a letter of the police phonetic alphabet followed by one or two numbers. For example, "Mary One" might identify the head of a city's Homicide Division. Police agency radio systems are assigned official callsigns however. Examples are KQY672 and KYX556. The official headquarters callsigns are usually announced at least hourly.

The United States Army uses tactical designators that change daily.

The United States Air Force uses semi-fixed identifiers consisting of a name followed by a two or three digit number. The name is assigned to a unit on a semi-permanent basis. For example, "JAMBO 51" would be assigned to a particular B-52 aircrew of the 5th Bomb Wing, while "NODAK 1" would be an F-16 fighter with the North Dakota Air National Guard.

External Resources

• Extensive information on amateur radio callsigns: http://www.ac6v.com/prefixes.htm