The country file, or CTY.DAT file, is a specially-formatted text file that is used by TR LOG, CT, NA, Writelog, DX4WIN, and many other Amateur Radio logging programs to determine DXCC entity, CQ zone, and other attributes of a callsign based upon the callsign prefix. It also handles exceptional callsigns, such as stations in Antarctica, stations where a callsign prefix does not uniquely identify a DXCC entity (i.e. 3D2, HK0, FO, FT, TO, VP8, ZK1,) stations where a callsign prefix does not uniquely identify a CQ zone (i.e. UA9, VE2,) or where a station is not in its default DXCC entity or CQ Zone (i.e. NL7AU is actually in the United States, CQ Zone 5, not Alaska, CQ zone 1.) Keeping this file up to date will ensure that TR LOG correctly accounts for multipliers worked, and correctly computes your score in DX contests.

Jim Reisert AD1C does a geat service for the Amateur Radio contesting community by keeping the CTY.DAT file updated. Updates are made periodically, often just before a major DX contest or DXpedition. Check the revision history to see if a new update is available. The CTY.DAT file may not display properly in your web browser. Hold the SHIFT key down while clicking on the link below, and your browser will prompt you to save the file to disk.

• Download the most recent file here: CTY.DAT.
• What has changed over time: Revision History.