Say happy 71st birthday to FM radio. The very first commercial FM radio station was W47NV in Nashville, and it began broadcasting on March 1, 1941.

W47NV (soon known as WSM-FM) was owned by the National Life and Accident Insurance Co., which sold the station after about ten years.

Sharing this birthday is the first non-commercial FM station: KALW, San Francisco. It obtained its license in March 1941, began broadcasting in September, and is still in operation today.

KALW is licensed to the San Francisco Unified School District and is the oldest non-commercial FM signal west of the Mississippi.

Electrical engineering genius Edwin Armstrong had proposed what is now called FM (frequency modulation) in 1922, and by 1934 was able to demonstrate how it lacked the static that often plagued AM (amplitude modulation) broadcasts.

Listen here (or download) to Profile America’s program about this anniversary. Profile America is produced by the Public Information Office of the U.S. Census Bureau.

Photo by Flickr user ilovebutter, used under Creative Commons license