Well, this friendly thread got active rather quickly. I don't know who said what. I'll consolidate my responses best I can. If I've missed some earlier posts and opinions, I'll come back and address them.
Auto AM/FM antennas are disguised many times, but REQUIRED, for any terrestrial radio, completely separate from GPS , Phone/Internet and satellite to make that clear.
Changing from an original whip antenna to aftermarket, changing length, or removing a whip basically disables your terrestrial radio. They're designed to "resonate" on certain frequencies, replacing with different equipment will reduce effectiveness on BOTH bands. Smaller antennas for looks may be great for your next "show off" meeting of vehicle enthusiasts, but it won't help you hear local stations on the road. They're simply not made for reception, they're made for owner's vanity in their vehicles.
31" Whips are the VERY BEST for FM and tuned perfectly for that band, and perform well for AM. HOWEVER, for many years, antennas for terrestrial radio have been disugised like rear windshield defoggers, small panels in side glass, often separate AM and FM with some kind of "amplifier/combiner" in the back of the vehicle which then feeds in one cable to the front.... and in the case of FM, a small squiggly wire inside the shark fin, which does very LITTLE for AM reception except make it ineffective. Amplifiers are sometimes employed to help, but..they seldom do. Digital Signal Processing to remove static or fade only serves to squelch the sound of AM and reduce the quality of sound if not the impression listeners get of AM.
As far as,
"So basically it's safe because other types of users wouldn't put up with its quirks and do the engineering to be able to use it well." I'd say you're slapping an entire industry. AM may be the oldest mass communications, but...it offers a wide range of terrestrial coverage. Any "Quirks" you refer to (such as "going away under a bridge" I assume ) also happen to XM/Sirius. Satellite also disappears when you go into a town with tall buildings on two sides of a street....As far as sound quality, don't blame the AM band, blame the owners of the stations. AM can sound excellent, with a wide stereo soundstage, and excellent detail in music... and can be just as impressive when owners care enough to process properly and pay attention to their source audio. Want to hear it? Visit my station's website. It's streaming AM in full stereo right now, and if WE can do it, any station could. We've updated old analog equipment and use all of the allowed bandwidth an AM can legally have. (
www.i1430.com or any device, but make sure you listen IN STEREO!)
AM is not going anywhere, Anyone who says it is has no idea how things work. The FCC rakes in MILLIONS of dollars every year from AM operators, small and large. Even when they reduce the yearly regulatory fees we pay to keep our 8-year license, they STILL make money. It's not going anywhere. Is it effective for other uses? No, but...there's plenty of good AM's in this country that are the lifeblood of a town, very much involved with listeners, and there's "quirks" in everything. Big cities often have AM stations if not in the top slot of ratings, at least a few of the top 10! In an age where consumers will listen to "music" on the speakers in a phone, AM can hold it's own and sound better than many digitally compressed audio sources.