FM Stereo Celebrates 50th Birthday

June 1 marked the golden anniversary of FM stereo broadcasting in the United States.

It was on that date in 1961 that three stations in Schenectady, Chicago and Los Angeles lit up 38 kHz subcarriers at midnight (ending May 31) in their respective time zones, and rolled out the stereo broadcasting with equipment that had been given FCC type approval only hours before.

The three stations — GE’s WGFM in Schenectady; Zenith Radio’s WEFM in Chicago, and Los Angles’ KMLA — became the first implementers of the backwards-compatible multiplex system for transmitting stereo signals, which was based on Zenith and General Electric inventions.

The transmission methodology — in which left and right signals are summed together and sent along the main FM channel, and a left/right difference signal created and carried by a multiplexed subcarrier — had been winnowed down from more than a dozen systems vying for FCC approval.

The early-morning June 1, 1961 FM stereo broadcasts lasted for only a few hours, but paved the way for a stereo transmission system that eventually gained global acceptance and even after 50 years shows no signs of fading away.

— James E. O’Neal

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FM was the best invent in the radio world and the stereo a step ahead. No digita radio can replace the dynamic, coverage of an FM transmission.
By Roy Sandgren on 6/7/2011
There were a handful of stations (fifteen I believe) that had transmitters made by GEL (General Electronics Labs) that were the first to be on the air in stereo. GEL had the first type accepted stereo generator and all stations that had a GEL exciter and stereo generator, were able to be the first FM stereo stations. The GE/Zenith system used in the June 1 broadcasts, was not type accepted. FCC type acceptance came later in 1961 and GEL was the first manufacture to get type acceptance. KFMB in San Diego, WDBN in Medina Ohio and WNOB in Cleveland Ohio were three among the very first stereo stations that employed GEL equipment. Does anyone know who the other GEL equiped stations were ? In the late 60's, the engineer for KFMB knew who the other stations were, I just can't pull that detail out of my head now, Too long ago..... The owner of WNOB, Philip Kerwin, told me that he was waiting for the FCC to issue approval for the GEL system and he flipped the switch the day the FCC issu
By Gary Saber on 6/3/2011

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