[BC] AM Stereo

[Robert Orban]

At 09:22 PM 11/25/2010, Jerry Mathis wrote:
>I understand and I agree with what you say, but we were talking 
>about sound quality, and not content.
>
>FWIW, I don't listen to Rush, and while I have nothing against it, I 
>don't listen to Coast to Coast either.
>
>Perhaps age has affected my memory, but I DISTINCTLY remember that 
>the advertised purpose of NRSC was not only to lessen interference 
>between stations, but to bring back high fidelity AM broadcasting, 
>with receivers again having close to 10 kHz bandwidth. Does anyone 
>remember a campaign (albeit weakly pushed) called AMAX?
>
>What's gotten my tighty-whiteys in a knot is that I'm now being told 
>that the whole purpose of NRSC was to benefit car manufacturers who 
>didn't want to deal with auto radio complaints. IOW, the AM 
>BROADCAST INDUSTRY bore the costs of benefitting the car makers--and 
>we got NOT ONE DAMN THING in return. Sorry for the profanity here, 
>but I think it's warranted.

Delco was the main receiver participant in the NRSC working group, 
and in fact, after the NRSC standards were implemented on the 
broadcasters' side, Delco created a line of radios that opened up to 
about 6 or 7 kHz (compared to about 2.5 kHz for their earlier 
radios), although IIRC this was only when they were receiving an AM 
stereo station. Motorola also offered variable bandwidth as part of 
the feature set in their CQUAM AM stereo decoder and Motorola was a 
major participant in the NRSC working group. (Motorola's Greg 
Buchwald was the person who first suggested the "modified 75us curve" 
that became the NRSC recommended pre-emphasis.)

So it's really unfair to accuse the receiver manufacturers of not 
following through. At the time, at least Delco considerably increased 
its radios' bandwidths as a result of the NRSC deliberations. 
However, I don't think that this survived the upheaval that Delco 
went through later.

As you pointed out, the AMAX campaign was created to tout the 
advantages of AM stereo and wider audio bandwidth. Ultimately, the 
whole effort slowly faded away, more because of consumer indifference 
than anything else. (Radio can also blame itself for not promoting 
AMAX more aggressively on the air.) It was too late to market AM as a 
high fidelity medium when consumers already believed that FM owned 
that turf. Meanwhile, stereo could not overcome the negative effect 
of the ever-increasing noise on the band, which the wider bandwidth 
radios only made more apparent.