June 9, 2013
Ever wonder how the call letters for your favorite TV or radio stations became what they are today? Call letters first developed for international purposes beginning with the transmission of ship calls. Pre-1906 radio work was conducted through Morse code. This allowed the abbreviation of the operator’s full name and location to one-to-three character identifiers. These usually included the ship, its personnel and geographic location. The stations “calling” each other were able to connect using the minimum amount of character identifiers.
By 1909, three letter identifiers (instead of one or two) were necessary to make sure ships were using distinct call letters. The United States Coast Guard, which was then referred to as the Revenue Cutter Service, used call letters that began with RC. An example of a typical call letter they would receive would be RC and then a third letter, like RCD.
In 1912, national call prefixes were established. The United States was given the authority to assign call letters beginning with K and W. K was used for Atlantic (East) and gulf-based ships and W was assigned to Pacific (West) based ships. Shortly after, the London International Radiotelegraphic Convention was passed, allotting call signs to many other countries.
Sailing into the roaring twenties, three letter calls were being overused so a fourth character was added. Soon after, the very first four-letter (and very popular) broadcast station WAAB was established on April 4, 1922.
In the 1930’s and 1940’s, the FCC required radio and TV stations to adopt unique call letters. Those call letters turned into large corporations and stations (WABC, WCBS, etc.) still around today.