The Story Behind Radio and TV Call Letters

Why do radio and television stations use three or four letters to identify their stations, and why do they typically begin with a “W” or “K”? It all started in the days of the telegraph when radio operators began to use a short series of letters to identify a location or shorten a name.

A problem arose, however, because there was no set standard on what call letters would be used based on a specific location. This led to a great amount of confusion, especially for ships, since they needed a unique identifier so two ships wouldn’t be using the same call letters. In 1912, the United States government stepped in and adopted a set standard that would use three letters to denote the location and the name of a particular radio operation station. Ships were assigned a “K” prefix if they were in the Gulf of Mexico or the Atlantic Ocean, and ships in the Pacific Ocean and the Great Lakes were assigned a “W” prefix. The international community also adopted this call sign format in 1912 and established that the first letter of the call sign would denote a particular country, though some were two letters or a letter and a number.

Land stations were a bit different and were assigned a “K” prefix if they were located west of a line that ran along the Texas-New Mexico border north to Canada, and a “W” prefix if they were east of this line. Things changed…