Coast to coast broadcast of the Mutual Broadcasting System

The Mutual Broadcasting System (MBS) first broadcast coast-to-coast in September 1936. The network was able to achieve this by affiliating with Don Lee Network, which added California stations to Mutual’s existing network. The expanded network began operations on December 30, 1936.
MBS was a commercial radio network that operated from 1934 to 1999. It was known for being the original network home of The Lone Ranger and The Adventures of Superman, and for its long-running radio coverage of The Shadow. MBS also broadcast Major League Baseball, the National Football League, and Notre Dame Fighting Irish football.

Mutual Broadcasting System Pacific coast debut December 30, 1936