Prefixes that are used for radio and television are usually allocated by ITU. They also form the basis for, but do not exactly match, aircraft registration identifiers. But in some cases, especially among amateur radio operators other, by ITU unallocated, callsigns are used when operating from disputed areas or countries that are internationally not (yet) recognized. They can be: unofficial - used by individuals without any issued permit temporary - issued by local authority official - recognized internationally by different organisations
Prefixes for those stations are either unallocated or unavailable by ITU definitions.
ITU unallocated and unavailable call sign prefixes
Unallocated: The following call sign prefixes are available for future allocation by the ITU. (x represents any letter; n represents any digit from 2–9.)
E8, E9, H5, J9, On, S4, T9*, Un, V9, Xn, YZ*, Z4–Z7, Z9, 4N*.
(* Indicates a prefix that has recently been returned to the ITU.)
Unavailable: Under present ITU guidelines the following call sign prefixes shall not be allocated. (x represents any letter; n represents any digit from 2–9.) nn, x0, x1, 0x, 1x, Qx (x0 and x1 prefixes remain permitted for callsigns beginning with one of the letters B, F, G, I, K, M, N, R, or W.) no prefixes beginning with Q are used—they may be confused with Q codes. no prefixes with the digits 1 or 0 are used—they may be confused with the letters I or O. two digit prefixes (nn) are not as yet considered by the ITU.
Table of Non-ITU radio prefixes
Call Sign Series State / territory Status Organisation(s)0 0Q Bavaria Official status unknown / unofficial N/A 0S Principality of Seborga Official status unknown / unofficial N/A1 1A Sovereign Military Order of Malta Official, DXCC entity SMOM Sovereign Military Order of Malta 1B Northern Cyprus Official status unknown / unofficial N/A 1B Blenheim Reef Unofficial N/A 1C Chechnya Unofficial - now RA6 N/A 1G Geyser Reef Unofficial N/A 1L Liberland Temporary Liberland Amateur Radio Association 1M Minerva Reefs Unofficial N/A 1S Spratly Islands Unofficial - now 9M0, DX0 or BV9, DXCC entity N/A 1SL, 1S Principality of Sealand Official status unknown / unofficial N/A 1X Chechnya Unofficial - now RA6 N/A 1Z Kayin State Official status unknown / unofficial N/AA A1 Jabal al-Tair Island Unofficial, no longer used - now J2A N/AD D0–D1 Donetsk People's Republic Official status unknown / unofficial UnknownH H5 Bophuthatswana Unofficial, no longer used - now ZS N/AM M1 San Marino Temporary, no longer used - now T7 N/AO O1 South Ossetia Unofficial N/AS S0 Western Sahara Official, DXCC entity Western Sahara's Amateur Radio Society (SØ1WS) S4 Ciskei (South Africa) Unofficial, no longer used - now ZS N/A S8 Transkei Unofficial, no longer used - now ZS N/AT T0 Principality of Seborga Official status unknown / unofficial N/A T1 Transnistria Unofficial N/A T4 Venda (South Africa) Unofficial, no longer used - now ZS Prefix is assigned to Cuba N/A T8 Principality of Seborga Official status unknown / unofficial Prefix is assigned to Palau N/AV V9 Vendaland (South Africa) Unofficial, no longer used - now ZS N/AX X5 Bosnia and Herzegovina Temporary, no longer used - now E7 N/AZ Z6 Kosovo Official in Kosovo, unapproved by ITU DXCC entity SHRAK Shoqata e Radioamatorëve të Kosovës
See also ITU prefix Amateur radio call signs Aircraft registration
References
External links Article: Kosovo - New DXCC entity? Prefix List (by CT2FZI) Northern Cyprus 1B: radio amaterur or radio pirate? Article: 1A: DX Entity with a 900 Year History Operational Bulletin No. 1149 (1.VI.2018)