How Amateur Radio Call Signs Are Built: Prefix, Type Letter, Zone Number, and Suffix
One string, four pieces of information
After passing the exam and receiving your license, the first thing most people memorize is not a frequency chart. It is their own call sign. Mine is BI4OAE. Six characters that look machine-generated, yet every segment has a documented origin. Learn the four parts and you can read a stranger’s call sign like a return address: which country, what kind of station, roughly which region, and often which province issued it.
The international frame: ITU Article 19
Call signs are not invented from scratch by each country. Since 1927 the ITU has allocated international call sign series, and amateur call signs follow Article 19 of the Radio Regulations (specifically provisions 19.68 and 19.69). The framework is simple: a prefix of one to three characters, chosen by the country from its assigned block; a separating numeral; and a suffix of one to four characters, usually letters. The prefix identifies the country or territory, the numeral and the rest are completed by the national administration.
The ITU assigns China the B block (BAA–BZZ), along with series such as VR–VRZ for Hong Kong and XSA–XSZ / XXA–XXZ for Macao. Because China holds the entire B block, every mainland Chinese amateur station begins with B. The prefix does double duty as a country code.
The Chinese structure: four segments
Under China’s rules for compiling and issuing amateur call signs, a domestic amateur call sign has exactly four parts: prefix, station-type letter, zone number, and suffix.
The first letter is always B. This is the ITU-assigned prefix for China, uniform nationwide, with no exceptions.
The second letter indicates the station series. General amateur stations use G, H, I, D, A, B, C, E, F, K, or L. Space amateur stations use J. Amateur repeaters and beacons use R. Letters S, T, Y, Z and some other series are reserved by the national regulator. Provinces may subdivide further: in Jiangxi, for instance, stations operated by organizations are placed in the A series — call signs beginning BA5 — to distinguish them from individual stations.
A widely circulated myth deserves killing here. Under the old four-tier certificate system, BA, BD, BG, and BI corresponded to the first through fourth operator classes, and many people still guess someone’s level from the second letter. That mapping is obsolete. In the current system the second letter is assigned by block and batch and carries no class information at all. The only way to know an operator’s level is to look at the operator certificate itself.
The third character is the zone digit, 0 through 9. It maps to a domestic region:
- 1: Beijing
- 2: Heilongjiang, Jilin, Liaoning
- 3: Tianjin, Inner Mongolia, Hebei, Shanxi
- 4: Shanghai, Shandong, Jiangsu
- 5: Zhejiang, Jiangxi, Fujian
- 6: Henan, Hubei, Anhui
- 7: Hunan, Guangdong, Guangxi, Hainan
- 8: Sichuan, Chongqing, Guizhou, Yunnan
- 9: Shaanxi, Gansu, Ningxia, Qinghai
- 0: Xinjiang, Tibet
The 4 in BI4OAE places the station in Zone 4 — Shandong, in my case. (Space amateur stations always carry zone number 1 regardless of location.) The zone digit is genuinely useful on the air. When you hear an unfamiliar call sign, the digit tells you roughly which direction the signal is coming from, which helps when judging propagation or sanity-checking an antenna pattern.
The suffix is one to four characters, letters or a mix of letters and digits. One-character suffixes, four-character suffixes, and suffixes containing digits are reserved by the national regulator; provincial regulators normally issue two- or three-letter suffixes. Certain blocks are off-limits: QOA through QUZ cannot be used, and combinations such as SOS, XXX, and TTT are excluded to avoid confusion with distress or similar signals. Within a zone, each province receives a distinct, non-overlapping block of two- and three-letter suffixes — in Zone 4, Shanghai, Shandong, and Jiangsu each have their own ranges — so the suffix can also hint at which province issued the license.
One person, one call sign
China follows a strict one-person-one-call-sign rule. When a regulator issues a station license it also issues a call sign, but if the applicant already holds one — repeaters and beacons excepted — no new one is issued. Operate from another province and you keep the same call sign; moving around does not get you a new one.
Repeaters and beacons follow a separate track: prefix B, second letter R, then the zone digit. Shandong’s repeaters use BR4, Jiangxi’s BR5, Guangxi’s BR7. When you hear a BR prefix you are listening to infrastructure, not an individual, and you should not read it like a personal call sign.
How other countries do it
The ITU pattern — prefix, numeral, suffix — is universal, but what the numeral means varies by country:
- United States: the K, N, W, and A prefixes cover the whole country, and the numeral indicates the district where the license was first issued. Before 1978, moving out of your district meant applying for a new call sign. Vanity call signs are available.
- United Kingdom: G and M prefixes, with regional letters appended when operating away from the home region (GW and MW for Scotland, GI and MI for Northern Ireland, and so on), plus 2-prefix series for the Intermediate licence.
- Canada: VA, VE, VY, VO, and CY prefixes with a region numeral — VA1/VE1 for Nova Scotia, VE3 for Ontario, VE7 for British Columbia.
- South Africa: in ZS1NAT, ZS is the prefix, 1 denotes the Western Cape, and NAT is unique to the holder.
And some countries let you choose. The US and UK both offer vanity call signs within their own rules. China does not: call signs are assigned by block, no one may request a specific call sign, and landing a pleasant suffix is pure queue luck.
Don’t overthink the suffix
Since you cannot pick it anyway, the healthy attitude is to stop caring. Whether the other station copies you depends on signal strength and operating practice, not on how your suffix sounds. Get the antenna up first; the call sign will take care of itself.
References
- ITU, Radio Regulations, Edition of 2024 — Article 19 (call signs, provisions 19.68–19.69) and the Table of Allocation of International Call Sign Series; in force 1 January 2025.
- ITU-R, Handbook on the Amateur and Amateur-Satellite Services, 2014 — call sign series and mutual recognition overview.
- MIIT (China), Measures for the Administration of Amateur Radio Stations (Order No. 67), in force 1 March 2024 — Articles 10, 18, and 24.
- MIIT (China), Requirements for the Compilation and Issuance of Amateur Radio Call Signs (annex to the Measures), 2024.
- CRAC (China Radio Association Amateur Radio Committee), How to Determine the CQ Zone of Your QTH, 2011.
- Jiangxi Provincial Department of Industry and Information Technology, Public Consultation Notice on the Jiangxi Amateur Repeater Plan and Amateur Call Sign Plan, n.d.