well its official

[Jeffhs]

Originally Posted by amptramp

Jeffhs, if you are looking for AM stereo, this was mainly used in car radios. I have found several of these from the late '80's and they did give some stereo separation and it was free of the multipath that you get on FM near large skyscrapers. But there were four formats vying for supremacy and by the time Motorola C-Quam won, there was no market. ESPN and talk radio does not need it. The biggest local station that went stereo used Khan-Hazeltine independent sideband modulation which few people built receivers for.

The only local AM station worth listening to is 1150 CKOC in Hamilton. It features mainly late 50's to early 70's pop and rock.

Ah! So that's why I never saw many (or any) AM stereo receivers during what was supposed to have been the system's heyday. Thanks for the info. I was thinking of home stereo systems that might have had tuners equipped for AM and FM stereo reception; there were few if any of these ever produced, that I was aware of at the time.

BTW, before the present U.S. stereo FM system was approved, there was a quasi-stereo broadcasting system known as "AM-FM stereo" in the late 1950s and early sixties. Under this system, two radio stations, one AM and one FM (usually operated by the same media group, but there may have been exceptions), broadcast both channels of a stereo music source--records, mostly. The system, from what I have read about it, worked, considering the state of the art at the time, but not very well. AM-FM stereo had major drawbacks, the worst of which being that listeners would lose fully one half of the stereo program if they were out of range of or could not receive, for any reason, the AM or FM stations carrying the broadcast. Another attempt at "stereo" broadcasting of television sound, before the advent of stereo television as we know it today, was to carry one channel on the TV station's own sound carrier, with the other being carried by a local FM station.

I understand, from reading a recent post by another AK member, that the above-mentioned method of quasi-stereo broadcasting was used, possibly on an experimental basis, to simulate stereo sound during NBC's "Friday Night Videos" music-video program in the mid-1980s. However, the show went off the air a few years later, and NBC's stereo experiments ended with it.

Television stations and networks began broadcasting true stereo sound, however, about 1986, the year NBC began stereo transmission; CBS and ABC followed suit shortly afterward. The NBC station in Cleveland began carrying stereo audio that year and has been doing so ever since, although it was not the first TV station in this area to broadcast in stereo; the first Cleveland station to transmit full stereo sound was the then FOX affiliate in Cleveland on channel 19, which was carrying stereo sound (and was probably the first television station in northeastern Ohio to broadcast in stereo) since it first signed on in 1985.

The state of the art continued to evolve, until it reached where it is now--5.1-channel Dolby digital surround sound which, as I understand it (I have a bookshelf stereo system that will work as a surround sound system, but I presently don't have and probably cannot get, because of the system's age [nine years], the extra two surround speakers), adds realism to TV programming heretofore unheard of. In other words, if you think (for example) a bomb going off on a TV program or movie sounds scary on a standard TV with its dinky little 5" (or smaller) transistor-radio speaker, it may well scare you out of your wits if you were to hear the same bomb going off in 5.1-channel Dolby digital surround, especially if the sound system has a 100-watt-plus amplifier.