AM Stereo Time Line

Ironically Stereo AM produces higher quality audio than IBOC AM. Yet Am stereo died struggling like Betamax did, in front of everyone and there was nothing we could do to save it. Stereo sound reproduction was first experimented with in the early 1900s, and was put into use in motion pictures around 1930. However, Stereo sound did not gain real market penetration until the introduction of the Stereo LP in 1957. More here.

Early experiments with Stereo radio broadcasting involved two separate stations broadcasting the Left and Right audio channels. Consumers did not accept this This Rube-Goldberg set up as it was just as ridiculous as it sounds.

In the early 1980s four competing AM systems went on air. These were:

1. Motorola (C-QuAM)
2. Magnavox (PMX)
3. Kahn-Hazeltine (ISB)
4. Harris Broadcast (V-CPM)
5. Belar System 

AM Stereo timeline Highlights:

• 1960 - AM Stereo first demonstrated on XETRA-AM, Tijuana, MX, using the Kahn ISB system.
• 1963 - WHAZ runs a stereo program on eight AM stations, four on each channel.
• 1984 - The FCC begins AM Stereo testing with five systems. Initially they select the Magnavox system. Their research is immediately accused of being flawed and incomplete.
• 1993 - FCC makes Motorola's C-QUAM the AM stereo standard. This sets off another series of lawsuits and accusations resulting in the FCC deciding that the marketplace should decide. The marketplace decides to continue fighting like children and this becomes a death blow to the possibility of AM stereo.

There are still over 100 stations still chugging along with stereo broadcast...
one that no one can receive, they are listed here.