The first M.W./F.M. stereo broadcasting

[Telecolor 3007]

When did took place the first M.W. (A.M.) stereo broadcasting and the first F.M. stereo broadcasting?

[Chad Hauris]

In the U.S., The first AM stereo was in the early 1980s, there were competing systems at that time...by the mid-late 1980s the Motorola C-QUAM system was the standard. Stations have been discontinuing AM stereo more in recent years with less music programming on AM and the advent of digital AM broadcasting.

The first FM stereo was in 1963 I believe.

Also in the late 50's/early 60's, some stations did stereo by broadcasting one channel of audio on an AM station and the other on an FM.

[Telecolor 3007]

So there was no stereo broadcasting in the '50's?

[Sandy G]

Prolly not, except maybe for some experimental stuff in the bigger cities, like New york, Chicago or Los Angeles. Stereo burst on the scene in like 1957-58.OK, I consulted "The Bible"- "Behind the Tube-a history of Broadcast Technology & Business", by Andrew Inglis, Focal Press, 1990, & it says "The National Stereophonic Radio Committee was formed in 1959 to examine methods proposed for transmitting stereo sound. After extensive studies the system proposed by GE was recommended & subsequently approved by the FCC in 1961." So there you go.-Sandy G.

[Tom Bavis]

And BEFORE the FM stereo standard was adopted... in the US, AM and FM were "simulcast" with left channel on one station, right on the other. In Japan, same was done with dual FM stations. In Australia, it was done with dual MW statons. You will occasionally find older receivers and tuners with one of these modes.

[wa2ise]

I can't imagine stereo done with one channel on FM and another on AM could have sounded anything but horrible. Unequal frequency response and noise for two things, but more seriously the phasing of the speakers of the two sets would randomly be in phase or in anti-phase. Depending on the speaker connections, the number of inversions in the respective audio amps, the phasing of the AM detector and how the antenna happens to capture the AM signal, and if the IF strip flips the phase or not.

Ever get the speakers on a stereo system out of phase? Gives a strange "pulled apart" effect on the ears.....

[Chad Hauris]

Many of the hi-fi AM/FM tuners of the late 50's early 60's have seperate tuning dials and seperate audio outputs for AM and FM to facilitate stereo with one channel AM and one channel FM. I guess you could test how the system would sound by listening to a station which simulcasts on an AM and and FM station (we still have a few of those here).

[Pete Deksnis]

When the first stereo LP's came out in the fall of 1957, it greatly increased the source material for in-home stereo, which was, up to that time for me, prerecorded tape (played on a VM 710 with 12AX7 tape-head preamp and an in-line stereo record/play head added).

That advent of the stereo record raised the awareness of stereo and so soon in the Philadelphia area WFIL and WFIL-FM began a 30 minute nightly broadcast in stereo -- as I can now frame it, sometime between late 1958 and early 1960.

Sure, all those phasing issues were there. My setup included a Heath FM-3 tuner heading a sorry hi-fi chain and a home-brew octal-tube AA5 modified with a 6AL5 as a voltage-doubler detector (lowered the distortion I had hoped, right wa2ise?).

Anyway, the thrill of the situation for an electronics nerd was the ability to cobble together a system and hear stereo over-the-air.

It didn't last long though. How many listeners could they have had?

BTW: The Fisher 800 had the dual tuning but was replaced with the FM-stereo 800B with just a single tuning knob.

[Tom Bavis]

Minor correction - the 800B still had dual tuning, PLUS an FM demultiplexer, 800C had a single tuning knob. I'm not sure about the earlier TA800, but since the Sams folder is sitting in my "to scan" pile at home, I'm sure I can find out...

[Pete Deksnis]

Back then I had an 800 with the dual tuning; never had the multiplex 'B' version; will be interested to hear what you dig out of the Sams...

Pete