How ITU prefix blocks work
The International Telecommunication Union (ITU) divides the world’s possible call sign beginnings into series and allocates them to countries. A series is a range such as “DAA-DRZ”, meaning every call sign whose first letters fall alphabetically between DAA and DRZ. That particular range is allocated to Germany. Once a country holds a block, its national regulator decides how amateur call signs are issued within it.
That is why you can often identify a country from the start of a call sign. If you are new to the topic, start with the main call sign prefixes list and come back here for the detail.
Reading a block
Blocks are written as three-character start and end points. Some are small and some are large:
- A single letter pair: “EIA-EJZ” covers call signs beginning EI and EJ (Ireland).
- A single digit prefix: “E2A-E2Z” covers E2 (Thailand).
- A wide letter range: “DAA-DRZ” covers D plus A through R as the second character (Germany).
Because the range is alphabetical, a prefix such as “DL” falls inside “DAA-DRZ” even though “DL” is not listed explicitly.
Examples by country
The ranges below come from the ITU allocation table as republished by the ARRL. Allocations can change, and this list is only a sample, so confirm anything important against the current ITU table.
| Country | Example series |
|---|---|
| United States | AAA-ALZ, KAA-KZZ, NAA-NZZ, WAA-WZZ |
| United Kingdom | GAA-GZZ, MAA-MZZ, 2AA-2ZZ |
| Germany | DAA-DRZ |
| France | FAA-FZZ |
| Italy | IAA-IZZ |
| Spain | AMA-AOZ, EAA-EHZ |
| Ireland | EIA-EJZ |
| Japan | JAA-JSZ (plus others) |
| Russia | RAA-RZZ (plus others) |
| Brazil | PPA-PYZ (plus others) |
| China | BAA-BZZ |
Countries with several blocks
Most larger countries hold more than one series. A few examples:
- United States: four main series, which is why you see K, N, W and the AA-AL range. Calls that begin with “A” followed by A through L are US calls.
- United Kingdom: G, M and the digit 2, and a country may issue different prefixes to different license classes or regions.
- Canada: the ITU table lists several ranges, including CFA-CKZ and CYA-CZZ, alongside the VA-VG, VO, VX and VY series. In practice you will most often hear VE, VA, VY and VO.
- Spain: both AM-AO and EA-EH.
Smaller series are sometimes split between two countries. A series such as “SSA-SSM” goes to Egypt while “SSN-STZ” goes to Sudan, so the second and third letters can matter.
Territories and DXCC entities
Operators who chase contacts with distant stations often care about “entities” rather than countries. An entity can be a territory, an island group, or a country, and it frequently has its own prefix. Hawaii (KH6) and Alaska (KL7) are examples within the US. The rules that define entities come from awards programs such as DXCC, which do not always match the ITU’s country list. If you plan to work toward an award, use the program’s own current entity list.
Looking up a call sign by country
To find the holder of a call sign:
- Identify the likely country from the prefix.
- Search that country’s regulator or national society database, if one is published. In the US, use the FCC’s license search.
- Try a worldwide lookup site such as QRZ.com or HamCall, which also cover many countries.
Not every country publishes license data, and personal details may be limited. If a lookup returns nothing, the call may be new, recently changed, or in a country with no public database.
Which country has the most operators
Reliable counts are hard to find because countries count licenses differently, some publish data and some do not, and licenses may lapse without being removed. The United States, Japan and Germany are often mentioned as countries with large amateur populations, but I would not rely on a single ranking without a current source. For the US specifically, the FCC database gives a licensee count.
What does 44 mean
“44” is not a standard code in amateur radio. The numbers that appear regularly are 73 (best regards), 72 (a QRP variation on 73) and signal reports such as 59. In some local conversations or other radio services, “44” may have a meaning of its own, so check the context where you saw it.
Related reading
- Ham radio regions and ITU zones explains the three ITU regions and how countries are grouped.
- The US call area map shows how the single digit in a US call sign relates to location.
- Use an azimuth map to find which way to point your antenna for a country you have identified.