[BC] AM Stereo

[Jerry Mathis]

I agree that there were some decent AM radios made for a short time. But Delco went through a major restructuring IIRC, and any improvements were lost. I also seem to remember that Chrysler's radio line had improved AM radios for a while. The demise of AM Stereo probably caused the receiver makers to discontinue the wide bandwidth mode, although AM Stereo is NOT required for that. They could have made it an option, with a switch so the listeners could choose.
 
Audio quality is one of the reasons (not the only reason, by a long shot) that I'm still hoping for the migration of the AM stations to a new FM band, digital or not.

--
Jerry Mathis

On Fri, Nov 26, 2010 at 12:24 AM, Robert Orban <rorban at dslextreme.com> wrote:
> 
>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.