In the January Automobile, Jamie Kitman bewails the current (sub)standard for AM radio in cars:
I have to be careful lest I start sounding like the guy who rhapsodizes on the wonders of vacuum tubes over solid-state circuits and vinyl versus streamed MP3 files, but AM car radios in their heyday sounded pretty good, and — counterintuitively — their reception was much, much better than in most new cars today. New cars all seem to retain an AM radio function — presumably for the day the nuclear weapons go off — but almost all of them suck. I kid you not. I get dramatically better reception in my 1962 MGA and my 1963 Jaguar Mark II than in the $127,000 BMW M6 convertible I drove last week. The BMW is not alone.
We will stipulate that vinyl is by design better than streamed MP3 files, but it’s hard to get vinyl to work in the center stack of a car.
The manufacturers, OEM and aftermarket, have pretty much decided that AM is a talk-only medium now, and they provide only enough frequency response to reproduce something resembling voice. There are only two AM stations I’d bother with for music around here, and one of them, a daytimer, has a 24-hour FM translator with 99 watts.