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Typically, radio stations have a 4-letter identification that goes along with their station number. You may have noticed that most of them either start with a W or K but have you ever bothered to learn why? Well, it all started with telegraphs.


Radio History

In 1912, several countries met for the International Radiotelegraph Convention to establish an agreement for radiotelegraph exchange. The most prominent outcome of the convention was the assignment of specific letters to certain countries allowing for easier identification of radio signals. The United States received the letters W, K, N, and A. Other nations received other unique letters such as Canada’s assignment of C and France’s assignment of F.

Although the United States was granted four letters, two were chosen for the American military radio stations. That left the country with W and K for commercial radio use. A few years later in 1928, the Federal Radio Commission made a few rules that are still in effect today. These rules required all radio names to be four letters in length and stations west of the Mississippi River were required to start their call names with K while stations to the east of the river were required to start with W.


Not Always Correct

However, some locations have stations that start with both K and W. When the federal government initially began labeling radio stations in the early 1920s, they wanted the west to get W and the east to get K, but the labeling got switched. The government also initially used the Texas-New Mexico border to draw the line between East and West. When the border shifted to follow the Mississippi River, some stations were not required to change their name to the correct corresponding letter. Furthermore, for about a year in the mid-1920s, the government decided that all new stations would start with K no matter the location.

Fun Fact: a St. Louis sports station recently changed their radio name to KRAP. They are highly recognized for their name and the fact that they talk Sports Krap 24 hours a day.


While not every station meets the rules, generally radio stations all have a 4-letter identification that starts with K or W, which is dependent on the location according to the Mississippi River.