What a call sign prefix tells you
Every amateur radio station is identified by a call sign, and the first characters of that call sign, the prefix, usually tell you which country or territory the license was issued by. Hear “JA1” on the air and you can reasonably guess Japan. Hear “DL” and you are probably listening to a German station. Learning to read prefixes is one of the quickest ways to make sense of what you hear on the bands.
This page is a starting reference. It explains how a call sign is put together, shows a list of common prefixes, and points to deeper articles on call signs by country, ham radio regions, the US call area map and azimuth maps.
Anatomy of a call sign
Most call signs have three parts:
- Prefix: one or two letters, sometimes a digit and a letter, identifying the country or territory.
- Numeral: a digit that, in many countries, separates the prefix from the suffix and may indicate a district or call area.
- Suffix: typically one to three letters that identify the individual station.
Take the US call sign W1AW. “W” is the prefix, “1” is the numeral, and “AW” is the suffix. In some countries the digit is part of the prefix itself, for example “3DA0” or “9A”, so the simple three-part model is a rule of thumb rather than a universal law.
Who assigns prefixes
Prefixes come from the International Telecommunication Union (ITU), which allocates blocks of call sign series to member countries. Each country’s national regulator then decides how to hand out call signs from its blocks. The ITU publishes the allocation table, and organizations such as the ARRL and the RSGB reproduce it for amateurs.
Because the blocks are allocated to countries, not to radio services, the same series is used for all kinds of stations. Amateur call signs are generally drawn from a subset of a country’s blocks, and the exact rules differ from one country to the next.
Common prefixes list
The table below shows some widely heard prefixes. Many countries hold several blocks, so treat it as a sample, not a complete list. For the official allocations, consult the ITU table or the ARRL copy of it.
| Prefix | Country or region |
|---|---|
| K, N, W, AA-AL | United States |
| VE, VA, VY, VO | Canada |
| XE | Mexico |
| G, M, 2 | United Kingdom |
| EI | Ireland |
| F | France |
| DA-DR | Germany |
| I | Italy |
| EA | Spain |
| CT | Portugal |
| PA-PI | Netherlands |
| ON | Belgium |
| OZ | Denmark |
| SM | Sweden |
| LA | Norway |
| OH | Finland |
| SP | Poland |
| R, UA | Russia |
| JA | Japan |
| VK | Australia |
| ZL | New Zealand |
| BY, BA | China |
| VU | India |
| PY | Brazil |
| LU | Argentina |
| ZS | South Africa |
Note that some of these, such as VA or EI, only cover part of a longer series. See the call signs by country article for how those blocks are divided.
Prefixes that are not what they seem
A few things trip up newcomers:
- One country, many blocks. The United States uses K, N, W and the AA-AL range. The United Kingdom uses G, M and 2. Russia, Japan and Canada also use several.
- Territories have their own prefixes. Hawaii is often heard as KH6 and Alaska as KL7, even though both are US states. Puerto Rico commonly uses KP4. Contest and DX operators treat many of these as separate entities.
- The number may not match where someone lives. In the United States the digit originally pointed to a call area, but operators can keep their call sign after moving, and vanity call signs let people pick one. See the call area map for what the digits mean.
- A prefix is not a guarantee of location. It tells you who issued the license, not where the operator is sitting right now.
Prefixes when operating away from home
When operating abroad or from another call area, operators often add a prefix or suffix to their regular call sign. A visiting operator might sign something like “DL/W1AW” to show a US call sign operating in Germany, and a “/P” suffix commonly indicates portable operation. Whether you may operate abroad, and what you must sign, depends on the rules of the country you are visiting and any agreements between countries, so check with the local regulator before you travel.
Looking up a call sign
You can look up most call signs in public databases. In the United States the FCC maintains a license search, and sites such as QRZ.com and HamCall provide worldwide lookups, usually with more detail for those who have chosen to publish it. Other countries often have their own regulator or association lookup. Not every country publishes its license data, so a lookup can come back empty.
Choosing a call sign
In the US, a newly licensed operator is normally assigned the next available call sign in sequence. Operators who want something specific can apply for a vanity call sign through the FCC program, subject to eligibility rules and a fee. Many people choose initials, a memorable suffix, or something that is easy to send in Morse code and say clearly in phonetics. Before deciding, read the current FCC rules and consider how the call will sound on voice and in CW. Other countries have their own processes, and some do not offer choice at all.
Related numbers and phrases
A few questions come up alongside prefixes:
- 73 means “best regards” and is a common sign-off in CW and voice.
- 72 is sometimes used by operators running very low power as a variation on 73.
- 59 is a signal report: readability 5 and signal strength 9.
- The “3-3-3 rule” is not a standard amateur radio licensing or operating rule that I can point to. If you saw it mentioned, it was likely a survival or local net convention, so check the source it came from.
Where to go next
- For how prefix blocks map to nations, read ham radio call signs by country.
- To understand ITU regions and zones, see ham radio regions and ITU zones.
- For the digits in US call signs, see the US call area map.
- To point an antenna at a prefix you just heard, try an azimuth map.