Charles David Herrold of San Jose, California is a relatively unknown broadcasting pioneer whos work began around 1912. He may have been the first to broadcast radio entertainment and information for an audience on a regularly scheduled, pre-announced basis. Over the years he used the call letters FN, 6XE, 6XF and SJN. None of these were formal, legal calls as there was no governing body to assign them. His early broadcasts were very innovative with a great number of "firsts."
Herrod broadcasted using a spark gap transmitter with a carbon element microphone. These elements burned out almost hourly making long form programming very difficult. Through experimentation he invented the "Arc Fone" Basicly it was six arc lights in series which produced a high frequency carrier signal. This unit required 500 volts. So he tapped the san Jose streetcar wires. Then he invented a water cooled microphone, the power of the device burned out the others. The Arc Fone was patented on December 21, 1915. http://users.adams.net/~jfs/herrold3.htm
in 1910 Herrold, published an ad for wireless equipment in the catalogue of the Electro-Importing Company "We have been giving wireless phonograph concerts to amateur men in the Santa Clara Valley." While his 1910 listeners were radio hobbyists, they still listened. he then went on to broadcast to much larger public audiences daily during the 1915 San Francisco World's Fair.
The real significance of Herrold was that between 1912 and 1917 he operated a radio station, programming on a regular schedule. A shceulde that was even announced in the newspapers. It is also noteworthy that the first woman to broadcast was his wife, Sybil. Among the firsts by Herrold was the radio give-away. He awarded weekly prizes to regular listeners. He was also one of the first time brokers, buying time from stations, and then re-selling it to others. At the start of WWI Herrod like almost everyone else was ordered off the air. After the war, Herrold had to rebuild his station to conform with the new standard of broadcasting. In 1921, the Department of Commerce assigned KQW as calls, the station is known today as KCBS-AM, San Francisco.
He died penniless, with almost no recognition; last working as a janitor at a naval facility.
KTEH-TV filmed a documentary of his life. You can order it here: http://www.kteh.org/productions/docs/docherrold.html I plan to.