Callsigns for the world’s nations are determined by the International Telecommunications Union (ITU), the United Nations agency that co-ordinates radio activity for all spectrum users.
The prefixes used by a country for both commercial and amateur radio purposes are determined from one or more ITU allocation blocks issued to that country.
The amateur radio callsigns in use for a particular country might use one or a number of combinations derived from the authorised ITU allocation(s) for that country.
The list available on the menu to your right shows callsign prefixes currently in use.
Most are derived from the callsign blocks allocated to administrations by the ITU for use within the countries, territories and dependencies for which a country is responsible.
Also shown are some unauthorized prefixes which may be heard and which may not be recognised as a DXCC entity.
Examples are 1S Spratly Archipelago and 1A0 SMOM.
Both of these are DXCC countries although the prefixes used are unofficial.
1B the Turkish area of North Cyprus and 1Z Karea State (Myanmar) are unofficial and are not recognised for DXCC purposes.
Full information on prefixes can be found in the RSGB Prefix Guide, which is available from the RSGB Shop.