This is a special version of CTY.DAT which is more tailored to everyday logging. For more information on what CTY.DAT is, go HERE

Version History

This version of CTY.DAT has callsign data starting with 1 January 2000. This is useful for people who are using contest logging software to log their everyday QSOs, and want somewhat accurate country tracking. Here are the features of this file:

  1. Exception callsigns go back to the starting date shown above. If a callsign was used multiple times, then only the most recent entity is used. For example, TO5M was used from Martinique (FM) in 1993, St. Pierre & Miquelon (FP) in 1995, and Reunion (FR) in 2004. Thus, if you log TO5M using this file, you will get Reunion (FR)
  2. Prefixes do not go back, they are current as of the day the file was released. For example, Montenegro (4O) was added to the DXCC list effective 28 June 2006. If you try to log a QSO with 4O1T in Yugoslavia from 2003, it will come up as Montenegro, because that’s the current entity associated with the 4O prefix. Here is a list of known problems.
  3. This is a complete file, meaning all prefixes that require CQ and/or ITU zone overrides are listed. This is primarily for BY, K, UA9, VE and VK – these entities all span multiple CQ zones. Remember that the normal CTY.DAT has only a subset of these prefixes; many have been implemented in software and therefore don’t need to be listed.
  4. Some software like CT by K1EA doesn’t save the country information in the log with the QSOs. Instead, the country for each QSO is determined when the program is started, based on whatever country file is in use. Thus, it may not be possible to “fix” a QSO that is associated with the wrong country. You could use the override method, like “FO8XYZ=FO0” to assign it to Clipperton Island. However, if/when you over-write your country file with a new one, those customizations will be lost. One known case of this problem is a certain well-known IARU HQ station that uses the same callsign from different DXCC countries, on different bands, at the same time. It’s very hard to get these cases right.
  5. This file comes in only one format: using ‘=’ to distinguish full callsigns from prefixes.

Installation Instructions

The instructions for installing the CTY.DAT file are specific to each logging program. However, the instructions for installing this file are the same as the normal contest country files, so start HERE. Follow the written instructions on that page, but don’t download the file from those links.

Here are some logging experiments to try to see if the larger file is installed in the right place, and is working:

  1. VERSION – should match the VERSION entity in the revision history
  2. OR4TN – should be Antarctica (not Belgium)
  3. MR6TMS – should be Scotland (not England)
  4. LW7DQQ/Y – should be Argentina in ITU Zone 16
  5. UI9XA – should be European Russia (not Asiatic)
  6. ZS85SARL – should be South Africa (not Marion Island)


Because of its size, this file may cause problems with your logging software. Here are some programs that are known to work:

CT 9.92 (DOS) and CT 10.04 (Windows) both work. Once can therefore assume that CT 9.92 (Windows) and CT 10.x (DOS) also work. It’s unknown how old a CT9 version can be and still work.
version 3.2.38 (Linux)
version 0.9.0 and later (Linux, Windows and macOS)
DL8WAA reports no problems.
version 3.1.1h and later
version 2.0.5 (Linux)

Areas for Improvement

Here are some changes that may be coming – stay tuned for details!

  1. The file contains all possible prefix mappings to determine the correct CQ and ITU zones. If people are only tracking countries, this may not be necessary, and would substantially reduce the number of prefixes in the file.