Why do radio and television station call letters start with ‘K’ west of the Mississippi?
It all started with telegrams. In 1912, several countries attended a conference centered on the subject of “International Radiotelegraphs.” One of the biggest things to come out of this gathering was the assignment of certain letters to certain countries, to identify their radio and television signals—America was given W, K, N, and A.
While N and A were chosen for American military radio stations, W and K were designated specifically for commercial use. Stations were allowed to choose the letters that followed the K or the W, and the combination was allowed to be three or four letters in length.
In 1928, the Federal Radio Commission decided on a few rules that remain in effect to this day:
- All radio/TV call names are required to be four letters in length;
- Stations east of the Mississippi River are required to start their call names with ‘W’; and
- Stations west of the Mississippi River were required to start their call names with ‘K’.
There are exceptions—such as KDKA in Pittsburgh—because existing stations were allowed to keep their old call letters rather than confuse longtime listeners with a new identity.