AM radio law opposed by tech and auto industries is close to passing | Ars Technica

Amateur radio operator here, I see some things in this thread that are kinda correct in this case but not technically accurate, and I'd like to provide the actual details:

I see folks asserting that "AM goes farther than FM." This is only accidentally true in this case. The stations that your car radio's AM setting can pick up are transmitting in the Medium Frequency (MF) spectrum, around 500 to 1600 kHz. The wavelengths here are around 200 meters. Radio waves with these wavelengths can refract around the Earth's surface, or at night bounce off the higher layers of the ionosphere, to be heard hundreds or thousands of miles away (respectively).

By contrast, commercial FM broadcasts are done right in the middle of the VHF band, from 88 to 107 MHz in the US. These waves don't refract off the ground or sky, and only travel in straight lines, so you have to be fairly close (within 75 miles depending on the height of the antenna) to hear them.

The terms "AM" and "FM" refer to how the audio signal is encoded on the radio wave; the short answer is Amplitude Modulation gets brighter/dimmer, FM gets redder/bluer. This is very little to do with how far the signal will travel, though it can have ramifications for how easy it is to hear near the edge of range and rising above the noise floor, etc. Both modes are relatively inefficient with power and bandwidth for different reasons; AM is primitive and FM is fancy.

AM radio is kept deliberately simple. Like, pre WWII simple. You can improvise an AM radio receiver with stuff you have lying around your house. I've seen a diode made out of a rusty razor blade and a pencil. It doesn't have the best audio quality, it's a bit of a waste of bandwidth compared to something like Single Sideband (which is cool but beyond the scope of this comment. Ask me about SSB if you want to hear about some cool radio shit) but it's easy to find or make a working AM radio. There's nothing that says you have to use AM on lower frequencies; aviation communication radios are AM (because we started using radios in planes before FM was invented) and they're in the VHF spectrum just above the FM broadcast band and just below the amateur 2 meter band.

FM is fancier, it chews up even more bandwidth depending on the exact implementation and is less power efficient, but it offers the potential for less natural interference, better audio quality, and they even broadcast it in stereo. There's just so narrow in terms of bandwidth you can make FM, which is why you don't find it in use below 10 meters (about 28 MHz); there's just no room for it. FM radios are more complicated, compared to a smart phone or PC they're pretty basic but you're not as likely to successfully improvise one out of shit you find in a tool shed.

In terms of sources for emergency information? I want both and more. AM broadcasting is the very definition of "good old" and relatively few stations can reach a national audience fairly easily, though FM stations typically take a LOT less power to run so I think they'd plausibly be up and running in a partial grid failure, and they're more localized. So for a national emergency I might tune into AM, for a local emergency I'm going to tune into my town's FM station that is 6 miles from my house.

I would also want a WX band radio. For those who aren't familiar, the National Weather Service operates a network of transmitters that broadcast continuous weather information on one of a dozen channels in the 160 MHz range, narrow band FM. If you've had a "weather radio" that's what that is. I know of very few car stereos that are equipped to receive WX band broadcasts and now that I think about it I can't imagine why it hasn't been mandatory for decades.

I have a hard time believing that ¼ of all Americans actively listen to AM broadcasts.

That being said, it's indispensable for emergency transmissions, and honestly not that complex a component to enable in modern radio systems.

AM is used for traffic advisory and weather conditions by state dots. A car without an AM radio cannot receive those safety critical broadcasts. An AM radio should be required equipment on every vehicle.

The argument for AM appears to be: the vast majority of adults will receive an emergency broadcast through their cellphone, but what happens if some event has already occurred which disabled large portions of the cellular network (which itself is an obvious target to create havoc)?

I'm fine with using AM as a redundant system for alerts.

Maybe make it more useful though for people in the car? I don't need an AM button I'm never going to touch. Instead have it monitor whatever the emergency broadcast frequencies are automatically, and put something on screen when there is an alert. That would make it a useful "modern" feature as opposed to appearing as a legacy holdover.

Requiring the installation of analog AM radios in automobiles is an unnecessary action that would impact EV range, efficiency and affordability (says the lobbyist)

Oh no the vehicle when driving at speed now uses 10001 watts with radio on instead of 10000 watts. Efficiency and range is ruined.

Also the $60k luxury vehicle is now unaffordable when a $1 am receiver is added in the infotainment

Lol. "Proponents claim it will reduce electric vehicle range". What a fucking joke.

Here's the thing about AM. Especially during any disaster. Damned near everything can get knocked out, power wise within 50 miles of you. At that point, you have no cell service, no data, and no FM radio. But AM? AM operates at a lower/longer frequency band. It can reach over double what FM can, and much further still, at night when it's signal can actually reflect off the ionosphere. Hundreds of miles.

So if shit ever REALLY goes down, AM radio is the most usable form of spreading information across the country. Bombs, freak accidents, mad scientist doomsday device, war, floods, tornados, etc. Anything that knocks a city out on power, AM will give you that information you'll need about where to go and what to look out for.

The right-wing hate talk radio protection act.

If they oppose it then I'm generally for it, sounds like AM Radio is used to broadcast safety messages on some roads in the USA so it makes sense. Plus, Radios are run of the mill common so it's not like it's any sort of barrier to entry.

Til am radio is still a thing? I know lots of fm radio stations but always wondered why every radio has an am setting, while there is no am stations available.

I don't think I've ever heard an AM transmission in my life, is there a benefit relative to FM or digital radio?

i thought all cars already have am

When did they stop?

What if, instead, we eventually phase out AM radio broadcasts and reclaim the frequency for other purposes?

Glad they have their fucking priorities straight. Cars are growing at an insane rate and becoming more dangerous to operate but at least they will have garbage AM radio.

Fuck congress