Why NBC’s Chime Changed On D-Day

They may be the most familiar three notes to generations of Americans — the NBC chimes that hit the notes G-E-C. The familiar chime goes back to 1929 when it was first used on the Red and Blue Radio Networks. The network was faced with the problem of how to cue local affiliates to take a station break, so the studio announcer hit the chimes every 30 minutes and listeners would hear station identifications from around the nation, such as “This is WJZ in Baltimore.” Several years after the three-signal chime was first used, a fourth was added, but was only deployed in extraordinary circumstances. The fourth chime was first used when the Hindenburg exploded over Lakehurst, New Jersey, in 1937. It also rang out for the Munich crisis of 1938, the morning of the Japanese attack on Pearl Harbor, then again early in the morning of June 6th, 1944, after Allied forces landed on the northern coast of France. Minutes after the four chimes were sounded, NBC newsman Robert St. John made the announcement: "Men and women of the United States, this is a momentous hour in world history. This is the invasion of Hitler's Europe — the zero hour.” Decades later, the days of using the fourth chime are long gone.