Amateur radio call signs are allocated to amateur radio operators around the world. The call signs are used to legally identify the station or operator, with some countries requiring the station call sign to always be used and others allowing the operator call sign instead.
The International Telecommunication Union (ITU) allocates call sign prefixes for radio and television stations of all types. Since 1927 these have been used to uniquely identify operators and locate amateur stations within a geographical region or country of the world. Call signs meant for amateur radio follow the ITU's Article 19, specifically 19.68 and 19.69.
Prefixes are assigned internationally, and a separating numeral plus suffix are added by a national body to produce this unique identifier. These prefixes are agreed upon internationally, and are a form of country code. Each country must only assign call signs to its nationals or operators under its jurisdiction that begin with the characters allocated for use in that country or its territories.
In some countries, an operator may also select their own "vanity" call sign that conforms to local laws. Some jurisdictions require a fee to obtain such a vanity call sign; in others, such as the UK, a fee is not required and the vanity call sign may be selected when the license is applied for. The FCC in the U.S. discontinued its fee for vanity call sign applications in September 2015.
In the US, the Federal Communications Commission's authority to impose and collect fees is mandated by Congress.
Effective April 19, 2022, a $35 application fee applies to new, renewal, rule waiver, and modification applications that request a new vanity call sign.
An amateur operator's call sign is composed of a prefix, a separating numeral and a suffix.
The prefix can be composed of letters or numbers, the separating numeral is between 0 and 9, and a suffix is from one to four characters, usually letters.
Examples of call signs and their constituent parts are as follows:
Call signs begin with a one- two- or three-character prefix chosen from a range assigned by the ITU to the amateur's country of operation or other internationally recognized jurisdiction. This is not necessarily always the amateur's country of citizenship. An individual operator is assigned a unique call sign beginning with this prefix and then completed with a separating numeral and suffix.
Beginning at the left of the call sign block, the country chooses one, two or three characters from within the range assigned by the ITU, enough to distinguish its call signs from other jurisdictions.
A "letter range" always first refers to the first letter of a block, meaning that in the letter range "AAA-ALZ", the "A" is the letter range-designator.
Factors for a country to consider when choosing within its assigned range:
The jurisdiction then assigns a single digit (a numeral to separate prefix from suffix) as well as a suffix of from one to four characters (the last being a letter) and appends them in that order to their assigned prefixes. The resulting call sign must uniquely identify a ham radio operator within that jurisdiction.
Sometimes the prefix plus separating numeral is together referred to as the prefix.
This produces internationally recognized, unique call signs to identify licensed operators.
In general an amateur radio callsign is of one of these forms where:
Call signs almost always have one of the following forms:
Since suffixes can also contain digits, some countries issue suffixes (usually temporarily) beginning with enough digits to produce a number, usually associated with the special event (for example the number of years, see New Zealand below).
In normal call sign assignment, if a call sign has two digits (e.g. S59DSC or 2S4LGR - PPNSSS), the first digit is almost always a prefix character (e.g. S5 indicating Slovenia, or 2M indicating Intermediate License holder in Scotland).
Call signs with two (or more) digits in them can arise a number of ways. When the digits abut one another, it is important to distinguish which digit belongs to the prefix, which is the separating numeral, and which may belong to the suffix.
In every case (Bahamas being an exception), a jurisdiction assigned a letter-digit prefix by the ITU will have a second digit as their internally assigned prefix/suffix separator. An example is A33A, a Tongan call sign; the first '3' is the second character of the prefix and the second '3' is the numeral separating 'A3' from the single-letter suffix 'A'. There are no single letter prefixes allocated by the ITU with an 'A', so the first '3' must be part of the prefix.
Neither New Zealand's nor the Republic of Ireland's prefixes have numerals as prefix-characters. However, both allow a second numeral as the leading character of the suffix and is not to be confused with the sign's separating numeral. As the first character of the suffix, the two digits can be taken together; for instance, to represent a two-digit number of significance to the operator.
A New Zealand amateur who has been active for 30 years and currently is assigned call sign ZL1xxx can operate as ZL30xxx for up to three months. Technically, the '3' is the separating numeral and the '0' is the first character of the suffix.
Similarly a club with call ZL4xxx which has been established for 23 years can operate as ZL23xxx for up to three months.
The New Zealand operator substitutes their identifying separating numeral with another, so long as a second digit is added to the beginning of their normal suffix. This may result in call sign confusion in the rare case of two amateurs in differing numeral-areas also both having the same number of years of operation and suffix.
Ireland also takes advantage of the ITU standard to allow digits as suffix-characters. The Irish Radio Transmitters Society operates as EI75IRTS celebrating 75 Years of incorporation - 1932-2007.
Ofcom in Great Britain also allows numerals in special event call signs. For instance GB75RD was a special event sign for the 75th anniversary of the Reading and District Amateur radio club.
Numerous other cases of multiple numeral prefixes exist. An example occurred in 1987 when the "200" was used in place of district numbers for the many stations that celebrated the bicentennial of the U.S. Constitution.
The 26 letters of the English alphabet and ten digits may be used to form call signs, accented letters excluded.
Letter combinations which can be confused with distress calls or which are reserved as abbreviations for radiocommunications services are excluded (e.g. Q codes). The ITU Article 19 exclusions are those found in ITU-R M.1172. In practice, no prefix begins with the letter 'Q', but 'Q' can be the second letter (eq. Malawi assigned the 7QA-7QZ block).
Double- or single-digit prefixes are excluded. A callsign with a leading digit in the prefix always has a second character which is a letter and in rare cases a third character which is also a letter.
Currently, no allocated prefix has 0 (zero) or 1 (one) as one of its characters as they can be confused with the letters O (Oscar) and I (India).
All ten digits from 0 to 9 are allowed to be used as a separating numeral at the discretion of national allocating bodies.
Ancillary prefixes or suffixes further identify the location and/or operating condition of an amateur operator.
According to the Canada/United States Operating Agreement treaty amateurs from one country operating in the other sign with their home call sign, but attach the call area prefix where they are operating to their call. For instance, an amateur from British Columbia (VE7 in Canada) operating in Washington State (K7 in the USA) would amend their home-call with a trailing /K7 (e.g. VE7xxx becomes VE7xxx/K7).
Radio amateurs from countries that apply the CEPT recommendation T/R 61-01 operating as a visitor in countries that apply the same recommendation are required to use the appropriate host country's prefix before their home call sign (in the case of Peru, after the home call sign) and may use the appropriate operating suffix (see below). For instance a British (English) amateur holding a call of G3xxx operating in France would sign as F/G3xxx, a Swiss amateur operating from a car in Germany as DL/HB9xxx/m. Similar rules apply in cases when bilateral agreements on visitors licenses exist, or a visitor is permitted to operate without being assigned a local call sign.
When a country's separating numeral denotes a geographic area within, an operator from one region operating in another region can affix a secondary suffix indicating so. For instance an amateur from Queensland, Australia, operating in Tasmania can sign as VK4xxx/7 or VK4xxx/VK7.
Other secondary operating suffixes can be attached such as /P (for portable operation), /M (for mobile operation), /AM (aeronautical mobile), /MM (maritime mobile), or /A (for operation from an alternative location that is registered with the licensing authorities). Depending on the jurisdiction, the use of these five suffixes may be required for these types of operation. Occasionally self-assigned operating suffixes such as /QRP for operation at low power are heard.
Some repeaters have automatic call sign transmission at regular intervals and use the secondary suffix /R at the call sign's end. Some jurisdictions discourage this practice on the grounds that it could be confused with an amateur from the repeater's location working portable in Russia. Similarly, some beacon stations use the self-assigned secondary suffix /B.
Each national authority has some options in relation to the form of the prefix, as long as enough characters are selected starting from the left of their assigned block to produce a prefix unique to its jurisdiction.
Each country has authority over which numeral separates the prefix and suffix. The prohibition of the use of the digits 0 and 1 in land mobile stations does not apply to amateur stations. The ITU however does not issue prefixes with either a 0 or 1 as one of the characters.
Bahamas issues call signs without a separating numeral. They are assigned the C6A-C6Z block, and the '6' is part of the prefix. Examples are as found on QRZ.COM (C6AFO, C6AGB, etc.)
INDIA In India the International Telecommunication Union (ITU) has divided all countries into three regions; India is located in ITU Region 3. These regions are further divided into two competing zones, the ITU and the CQ. Mainland India and the Lakshadweep Islands come under ITU Zone 41 and CQ Zone 22, and the Andaman and Nicobar Islands under ITU Zone 49 and CQ Zone 26. The ITU has assigned to India call-sign blocks 8TA to 8YZ, VUA to VWZ, and ATA to AWZ.
VU call-signs are listed according to licence grade: for General (formerly the Advanced Grade and Grade-I) licence holders, the call-sign prefix is VU2; for Restricted (formerly Grade-II and Grade-II Restricted) licence holders, the prefix is VU3. The VU3 prefix has also been granted to foreigners operating in India. As of 2011, call-signs consist of only letters, not numerals, and can be either two or three characters long. Examples of Indian amateur radio call-signs are "VU2XY" and "VU3EGH".
The suffix can be from one to four characters subject to ITU exclusions (above). On special occasions, for temporary use, administrations may authorize use of call signs with more than four suffix-characters.
Whereas for ITU purposes the prefix does not include the separating numeral, for country purposes often the separating numeral is included when the prefix is referred to. Thus for Canada VE6 or VA6 are the prefixes for Alberta, while VE2 or VA2 are the prefixes denoting Quebec.
A country can consist of many DXCC entities depending on its geographical make-up. Some islands which are separate DXCC entities are uninhabited and can only be worked when a DXpedition travels there. The following are countries and/or entities which appear perennially on various listings of rare countries:
Countries which are rarely heard, roughly in this order:
Islands which are rarely heard DXCC entities:
As political boundaries change through treaty or warfare, sometimes call sign prefixes are reassigned by the ITU to the new controlling government, or are reassigned by national governments for other reasons.
Some call sign block ranges are unassigned by the ITU, e.g. the 1AA-1ZZ and QAA-QZZ blocks. Any call sign used by an amateur in these unassigned block ranges usually had it assigned to them by a group with an unrecognized national claim. Unless otherwise noted, they have no value for DXCC awards, nor are they valid under UK license conditions.
In addition, during their period of independence from the Republic of South Africa, which lasted in some cases from 1976 to 1994, the Bantustans had prefixes not recognized by the international community. These were:
Amateur radio call sign prefixes almost always locate an operator within one of the 300+ DXCC entities in the world.
Any country or ITU prefix assignment can have many entities within it. For example, in the United States Hawaii (with 'H' as the second character of the prefix and '6' as the separating numeral) and Alaska (with 'L' as the second letter of the prefix) are considered different DXCC entities, as are Sable Island and St. Paul Island in Canada.
The DX Century Club (DXCC) is an amateur radio operating award given by the American Radio Relay League (ARRL) to operators making contact with 100 or more geographic entities around the world. As such, the ARRL keeps a list of DXCC entities (not necessarily a country) for this purpose. This list includes deleted entries and prefixes and the dates in which contacts with them will be counted towards the award.
The DXCC List is based upon Clinton B. DeSoto's landmark 1935 QST article defining a "country" as a discrete geographical entity. A geographical portion of one country can be a separate DXCC entity if it is an exclave or an island or group of islands significantly distant from the main part of the national entity.
IOTA is a radio amateur abbreviation for "Islands on the Air". It refers to a list of saltwater islands worldwide maintained by the Radio Society of Great Britain, which assigns a unique code to an island or group of islands, like EU-005 for Great Britain, OC-001 for Australia etc. IOTA codes are not part of the callsign, although some callsign blocks correspond uniquely to an IOTA code, like EA6: EU-004 - Balearic Islands, SV5: EU-001 - Dodecanese Islands, etc. In many other cases there is no direct relation between the callsign and the IOTA code.
Individual amateurs may want a callsign with their name or initials embedded, callsigns that had been held by family members or friends, or callsigns that they themselves formerly held (and gave up for whatever reason). Some people want a callsign that is shorter, or easier to pronounce, or just "fits their personality" better. CW (Morse code) operators might want a callsign that "sounds good" or is short when sent in Morse. (This is referred to as "CW weight".)
Radio amateur clubs will sometimes request specific callsigns in memoriam of deceased members (silent keys); G5RV is held by a British club in memory of the inventor of the G5RV antenna. Some request callsigns which reflect specific interests or modes of operation (such as VE3QRP for a low-power radio club in Ontario). The USS Batfish, a museum ship in Muskogee, Oklahoma, has callsign WW2SUB; the USS Oklahoma is commemorated as WW2OK. The Battleship USS Missouri has the call sign KH6BB; VO1TAP is a callsign belonging to the Grassroots Amateur Radio Club, commemorates the anniversary of the USS Truxtun and USS Pollux Naval disaster off the coast of Newfoundland; VO1MCE the callsign of the Irish Loop Amateur Radio Club at the Myrick Wireless Interpretation Centre in Newfoundland, commemorates Cape Race Marconi station MCE as the first point of radio contact in the New World for Titanic. The National World War I Museum and Memorial, at the Liberty Memorial, in Kansas City, Missouri, has the call sign WW1USA.
Various "special event" callsigns are issued for periods ranging from a day to a month, either for individual radio contest days or commemoration of specific current or historic events. GB100MGY commemorated the 100th anniversary of the sinking of Titanic (Marconi station MGY); 2O12 and 2O12L commemorated the 2012 Olympic Games in the United Kingdom.
Occasionally, a radio club will obtain a shorter callsign for a day; the U.S. FCC issues calls as short as 1 × 1 (with "K1D" being a popular choice) for individual events. These callsigns are not permanent and are quickly reassigned to other stations for subsequent events.
A well-known short callsign is JY1, which belonged to Hussein of Jordan, who served as that nation's king.
Ham radio operators in the United States may apply for a specific callsign, including calls from other zones, so long as they have the appropriate license class for the desired callsign format. The callsign must conform to the prefix standard assigned to that area. The U.S. also ties callsigns to license class: an Amateur Extra might have W0OL (which is a "1 × 2" call), but a General-class licensee could not, because 1 × 2 calls are reserved for the Amateur Extra class. Likewise, a ham on the mainland could not get a callsign beginning with the KH6 prefix, which is assigned to Hawaii, although a radio amateur who moves to a different call sign district within the same country is able to keep his or her original callsign.
In Canada, a "2 × 3" call (a format with two letters, a number, three letters, like VE1ZZZ) may be freely requested from a list of available calls; the shorter "2 × 2" call has a waiting period in many provinces.