A controversial bill that would require all new cars to be fitted with AM radios looks set to become a law in the near future. Yesterday, Senator Edward Markey (D-Mass) revealed that the “AM Radio for Every Vehicle Act” now has the support of 60 US Senators, as well as 246 co-sponsors in the House of Representatives, making its passage an almost sure thing. Should that happen, the National Highway Traffic Safety Administration would be required to ensure that all new cars sold in the US had AM radios at no extra cost.
You can improvise an AM radio receiver with stuff you have lying around your house.
Not only that, it can be powered by the radio signal itself.
https://en.wikipedia.org/wiki/Crystal_radio
A crystal radio receiver, also called a crystal set, is a simple radio receiver, popular in the early days of radio. It uses only the power of the received radio signal to produce sound, needing no external power. It is named for its most important component, a crystal detector, originally made from a piece of crystalline mineral such as galena.[1] This component is now called a diode.
Crystal radios are the simplest type of radio receiver[2] and can be made with a few inexpensive parts, such as a wire for an antenna, a coil of wire, a capacitor, a crystal detector, and earphones (because a crystal set has insufficient power for a loudspeaker).[3] However they are passive receivers, while other radios use an amplifier powered by current from a battery or wall outlet to make the radio signal louder. Thus, crystal sets produce rather weak sound and must be listened to with sensitive earphones, and can receive stations only within a limited range of the transmitter.[4]
This is just making me think that there should be a fundamentals of modern technology class in high school somewhere between a shop and physics class. It’d be a nerd elective but by fuck am I that nerd
Something between shop class and engineering. Like Technician class. I like it.
Yeah as an engineer I think it would’ve been far more useful than the engineering class I took that was basically how to do autocad and measure things. And it would’ve been useful for everyone.
There are two things at play here. 1) one of the primary purposes of the United States’s education policy is to produce engineers. This is an economic and military strategy. And 2) we live in a world where technology abounds and yet so few people understand it. A robot isn’t a magic person made of metal, it’s the manifestation of the laws of physics as applied for our own desires.
Making a radio receiver and a telegraph and a record and telephone and a basic battery etc makes for more grounded adults. Show the teenagers the way the real world works, clever applications of natural phenomena
100% accurate, thanks for the clear write up. Please stick it up on Wikipedia if you can :)
And I’ll add a bit about Clear Channel AM (unrelated to the billboard advertising company) - there were originally a handful of said stations that broadcast on a few AM band frequencies that are reserved just for them, so their broadcast range is impressive.
One for example is WOR radio in Chicago.
Fun factoid - you can see on very old AM radios those clear channel frequencies marked by a diamond or similar symbol on the dial.
Holy crap, I have an old radio (a few feet from me) for a decade and I had no idea what the diamond symbols on it were for. Thank you!
Tell us about ssb. I also just bought an SDR to get my gas meter readings. Any other cool stuff I should check out?
Single Sideband is basically AM 2.0, so to talk about it in detail, we have to take a closer look at good old fashioned 19th century AM.
The graphic above is from Wikipedia. The top graph, the “baseband” signal, is the audio, aka the signal coming out of the microphone. It’s vaguely what a human voice would look like on a specrograph.
The second graph is what AM looks like. The spike in the middle is called the “carrier.” Let’s say you’re transmitting on 5 MHz with a 10 watt radio. When you push the talk button and then say nothing into the mic, you start broadcasting a 5 MHz wave with a power of 10 watts. A receiver tuned to 5 MHz will hear the background static go away, because you are transmitting a carrier wave that does not modulate much louder than the background noise, you are effectively holding the receiver’s speaker still. A signal coming in strong enough to do that we call “full quieting.”
The carrier carries no information. Another way to look at these graphs is, picture the sine wave. You may have seen something like this before:
That middle waveform represents AM, notice how there’s always some squiggles going through the middle, and it varies toward the top and bottom edges? That’s what the upper graphic is representing, that big center spike is always there for that reason.
You may notice that the two lobes to either side are the same shape as the base band signal; or one of them is, the other is a mirror image. We call these sidebands. That’s actually where the audio is. In the second graphic, you can see how the top and bottom edges of the AM waveform resemble the baseband signal. Turns out, AM radio uses twice as much bandwidth and more than twice as much power to transmit the usable signal.
So what if we built the transmitter to only transmit one of the two sidebands and suppress the carrier and the other sideband? The same audio information goes over the air, and we take up less room on the radio spectrum to do it. What’s more, since we’re transmitting less overall “stuff,” the radio’s power is more focused on the part we do transmit, so a single sideband transmission comes across as “louder” than an equivalent AM transmission.
There are some cool upshots to how SSB works: the first is that the radio uses less power and overall stays cooler. AM (and FM) transmit with their full power all of the time, doesn’t matter if you whisper or scream into the microphone you’re putting whatever power your amplifier is set to out to the feed line. You might be transmitting silence, but it is very loud silence. SSB doesn’t do that; the louder you talk into the mic, the more power goes out the antenna. You aren’t constantly transmitting that carrier, so if your mic goes quiet, so does your antenna. Thus, your transmitter gear takes less power, runs cooler, and if you are on some consumable power source like batteries, you can transmit more effective power for longer.
Even cooler than that is the lack of collisions. If you’ve played with radios much, even listening to music radio stations near the edge of their ranges where you can kind of hear both, you know they interfere with each other. Happens all the time with aviation radios, pilots will transmit on the same frequency at the same time and anyone else listening gets to listen to the psychedelic sounds of two carrier waves interfering with each other. On FM radios usually the louder signal “wins” and the other one just sounds like static or interference under it. SSB doesn’t do this.
If two people transmit at the same time on the same frequency on SSB, a third person listening just hears two voices, just like if two people talked at the same time in a room. Hams hold contests to see who can make contact with the most people from the most places, and folks from somewhere rare will end up asking for contacts, everyone else says their callsigns at once like it’s the floor of the stock exchange, the one station will pick someone he heard to exchange details with, rinse and repeat. It’s 1950’s Discord.
Hams also use this technique to send text back and forth extremely efficiently. If you tune your software defined radio to 14.070 MHz (or use one of several people make available online) you might hear what sounds like several strange warbling whistles that come and go. That is PSK31, a digital text mode designed to use an ordinary PC sound card as a modem, and an ordinary SSB transceiver to send the signals across the air. Using software like FLDigi, you can receive and transmit text over the air, and each text transmission is very narrow in bandwidth. Over a dozen can take place in the same space as a normal voice channel, you leave the radio tuned to 14.070 and choose which transmission to listen to by clicking on them in the waterfall, ie choosing what audio frequency to listen to, which only works using SSB because no carrier collisions.
For all its advantages, there are some disadvantages. You cannot transmit “quiet” with SSB the way you can with AM or FM; so the background static, the “noise floor” is always there. Makes it not so nice for listening to music, which is why you basically only ever see it on communication radios. And it also requires a much more complicated transmitter and receiver while achieving the same or slightly worse audio quality than AM. You don’t see SSB used much in VHF and above because there’s so much room for activities/line of sight limits how far your signal goes so the efficiency advantages of SSB are less important, which is why we tend to use FM (or AM for old shit like airplanes) at wavelengths shorter than 6 meters or so.
Very nice write up. I am curious, is the long wavelength Responsible for the rise and fall in audio quality depending on where you are. I have had this happen as I was driving, the sound quality seemed to pulse.
Also I used to live right at the base of a tall mountain range there was a AM transmitter on the other side less than 100 miles away. During the daytime I could never receive it, at night it would bounce over the mountain and it was pretty clear.
I doubt the wavelength is a factor there; depending on the circumstances it could be anything from atmospheric waves to something in your car causing intermittent interference.
The Earth’s ionosphere exists in several layers. During the day, solar radiation ionizes gas deeper into the ionosphere causing a layer that doesn’t usefully refract most radio waves; you can reach beyond the horizon on some of the higher HF bands, but down in the MF, you’ve basically got ground wave. At night, without the sun around to cook the atmosphere, that lower level dissipates, revealing a higher ever-present layer, and the geometry is right to refract signals for hundreds or even thousands of miles.
Skywave propagation can be really fun to play with.
That truck was a old fucker. It had AM and a 8 track. So I wouldn’t be surprised if the radio shielding was limited and degraded…
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.
I grew up with a dad who listened to Rush Limbaugh or some conservative jockey (Mike Savage was quite bonkers, still cannot believe he got hired by MSNBC for about 2 weeks before he said some insane racist shit and got canned) on AM anytime I was ever in the car with him.
He’s now a QAnon nut.
I absolutely believe 25% of America listens to AM radio, all the christo fascists and qanoners and magatards on their 3 hour daily commute while they are angry that their kids or ex wives don’t talk to them anymore.
He’s now a QAnon nut.
I was just thinking that I hadn’t heard much about Qanon lately, that maybe it had been fading out. No?
Coincidentally, Q posts dried up when John McAfee died. I wonder why that is
Sadly, it has not so much died out as gone more underground, splintered, but still proliferates.
Take a gander at owen morgan’s telltale youtube channel, he actually covers a good deal of this quite well.
He started off as an Ex JW going over online and real world cults, but as QAnon and Covid and MAGA and then Jan 6th all kind of morphed together, he finally dropped his ‘avoid politics’ stance as it was utterly impossible to cover anything related to QAnon without getting political.
Basically, 8kun, Truth Social and other less well known sort of youtube alternative sites and alternative social media sites have just become an alternative reality fantasy land for completely delusional conspiracy theorists and outright fascists and nazis.
Then youve also got a ton of shitty MAGA/QAnon flavored ‘news’ sites (think infowars and breitbart, there are many others) that post absolutely insane nonsense as real, or report on various things leaving out huge details, misrepresenting situations and such.
Their content is then watched and discussed and meme’d and spread on telegram group chats, facebook groups, an increasing number of either online or radio talk show hosts, and by a number of surprisingly popular evangelical preachers, many of whom have basically megachurches as well as their own video streams.
Thats the link that owen came across that kind of led him to be able to figure out how much of the QAnon related mis and disinfo network actually functions, when he discovered a bunch of, again, surprisingly popular evangelical and or charismatic preachers who have decided that basically they are prophets, God literally speaks through them, and Trump is actually the new annointed messiah who is God’s chosen President.
They had made a bunch of prophecies about Trump winning 2020, so when he lost, they basically developed the idea that Trump is actually the President of God’s annointing… as a cope for losing and being failed prophets.
But this idea has stuck, so now anyone opposing God’s President is a demonic force of Satan, blah blah blah.
So… basically QAnon and its derivatives are still going quite strong, they have just largely abandoned platforms that most people know about, or are in largely private groups on more well known means of communications.
I remember seeing one video on one of these youtube alternatives that explained that nuclear weapons are actually fake, dont work, never have, and thus the end of ww2 and the entire cold war and modern day geopolitics are all an elaborate ruse orchestrated to keep us all compliant and afraid… blah blah blah, somehow, its always liberals, democrats, jews and socialists, or secret versions of those, that have been orchestrating a mass conspiracy for a hundred years or something.
We have also had a number of right wing mass shooters, guys that tried to kidnap the governor of Minnesota, and the person who immolated himself outside Trump’s trial… all with QAnon related or derived beliefs.
We now also have certain preachers just outright calling for a christian nationalist government, and they all can be connected to this wider movement stemming from QAnon.
Just because Q has not posted in a while doesnt mean the movement that was sparked and coalesced by and around his garbage has died out.
Same, though my dad was liberal. He just kind of rage listened to these guys. Needless to say, I was young and impressionable and picked up some of their extreme views in my youth, but later got straightened out when I went to college. Fuck AM radio. It is responsible for radicalizing people who spend a lot of time in their vehicles. We should not require it in vehicles. I feel the damage done outweighs the potential benefits from emergency messaging. Everyone has a phone for that these days anyway.
And now you’ve figured it out. This probably has nothing to do with emergency preparedness and everything to do with keeping a propaganda pipeline open. Maybe the D votes are secured by arguing about emergencies, but I just don’t see it.
Recommend people get an AM radio for emergency use, but it doesn’t need to be required for every vehicle.
I have seen the movie, and it is extremely hard for me to watch.
After years of debunking insane nonsense from my Dad, only for him to come up with some new insane thing, then declare he is done with politics, then mention off hand something he could only have possibly heard from some insane QAnon type nonsense, I finally realized he’s an egomaniac incapable of being wrong, doing any self reflecting, who has no problem knowingly lying to those around him, about himself and those around him.
It was very hard for me to realize that though he says he loves me and has attempted to demonstrate this, interacting with him in any way other than coddling his feelings, entertaining his nonsense … just results in him being classic narcissistic asshole.
Better off without him in my life. So, so much less stressful.
I know that back in the early 00s I was traveling cross country and was surprised when I reached the prairies and realized there were way more AM than FM stations, but it’s because AM travels much farther even though the fidelity is lower.
even though the fidelity is lower.
That’s the trade off you make with AM. With just about all wireless transmission techs, really. There seems to be an inverse relationship between range and bandwidth. If you want one, you sacrifice the other. Compared to FM, AM radio leans more towards max range, so the audio quality isn’t quite as good, but it goes for miles.
And thats how you get all the people living in rural America who listen to AM nonsense talk radio.
Its also much, much cheaper in general to start your own AM talk show because of the relatively lower costs compared to FM broadcasting, so any crazy angry idiot can do it.
l’d think that the Internet (well, systems built on the Internet) has probably been the most-influential system for lowering the bar to transmit ideas in recent years. I mean, it’s really inexpensive and easy to post on social media, and that can reach a whole lot of people.
A lot of EV auto makers have been arguing that the frequencies that some of the electrics in the cars run at interfere with AM radio reception.
Not sure if that’s a legitimate argument or they just don’t want to pay for extra shielding to block out the noise.
Sounds like they are admitting that their cars violate FCC rules about interferance.
A lot of sports radio, npr, and conservative radio stations are on AM. I listen to two of those three, though most the stations I listen to have an app or streaming option I use more often then actual radio.
Found this list, and they’re surprisingly spread out across the county.
(There’s 57 of them on the list for anyone that doesn’t feel like clicking)
The average American is 38.x years old. There are a lot of children, but the olds still run this country. China is around 37, Germany is around 39. I don’t think that 25% of America listens to AM broadcasts on a regular basis, but I do think at least 1/4 of the population thinks it should still exist.
I was referring to a quote from the article where someone stated that 82 million Americans listen to AM radio.
Coincidentally, I am above average, think that AM radio has utility, and am not opposed to requirements that it be made available in car stereos - though I do not actively tune in.
I’m opposed to it, if the argument is basically “for emergencies”… then putting an emergency radio in would be better. At that point, just lump into the spare kit or something.
Nobody in an emergency is going to think to use something that they don’t use in every day life. Having AM radio in cars is… not going ti be useful. (EAS goes out on FM amd say radio, too, and there’s the WEA sent to cell phones for people younger than dirt.)
and if SHTF, powering a car is going to be difficult. You basically can only rely on the gas in your tank and what you keep around for the lawn mower (if that.).
Most emergency radios are designed with minimal power from the get go (ie battery operated, recharged via hand crank or portable solar, etc.) and can usually be set to automatically come on if the EAS sends an alert.
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.
AM radios are also incredibly cheap and simple. It’s just one more source for a digital stereo system connected to a fairly simple circuit. I doubt this costs more than $5 per car to implement.
Oh my god, we’re gonna have to increase the cost of cars and trucks by at least 8000 dollars to cover this egregious and unfair regulation! - Automotive CEO.
AM radio costs nothing to implement, that’s not why it’s absent from me cars. Many modern cars use some form of brushless motor in the power train. The inverters for these motors work at a frequency that interferes with AM radio reception at close range. Manufacturers can add it back to cars (probably by an over the air software update as many radios are SDR), but it’ll just pick up whistling when the car’s moving.
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.
I haven’t been following the situation, but it sounds like we haven’t even really managed to get terrestrial digital broadcast radio functioning all that well for audio. Things have kinda fragmented into three separate standards (HD Radio in the US, and Digital Audio Broadcasting and Digital Radio Mondiale in Europe).
I think that if it’s going to reach the point of mandating inclusion of newer radios, it might be preferable to sit everyone down and come up with some kind of broadly-acceptable single standard before we start baking it into legislation.
Also, if we’re gonna have a way of talking to the car’s computer remotely, for displaying alerts or whatnot, I’d rather that the protocol be cryptographically-secured from the get-go and that the modules be hardened as best we can. I don’t really want to deal with little Jimmy with a $10 USB radio and a laptop dicking up autos at scale.
There isn’t a way to do it, digitally. It’s all radio waves. The lower the frequency, the longer the wavelength, the less information it can carry, but the longer it can travel and get picked up on an antenna. AM operates and can have audio heard/understood at a much lower frequency than a digital signal. AM operates in the KHz range. FM is in Mhz, and digital radio operates in Mhz, as well. Specifically, digital radio is broadcast at around 175Mhz, on the low end; while AM radio is around 1,000 Khz.
Thing is, it takes 1,000Khz to equal 1Mhz. That means that digital radio signal is flinging out data around 175 times more than the AM frequencies could, so it can’t reliably transfer nearly as far. There’s also a hard line on digital signal interpretation. Once there’s a threshold hit for not picking up enough signal to fully interpret it, you drop straight to getting nothing interpreted. It’s like how now that all tv signals are digital, so you either get a picture that looks perfect, or you get nothing. Back in the analog days of television you would often get fuzzy pictures and audio. The TV was able to interpret whatever signal it did manage to get, even if it wasn’t all of the signal.
AM operates and can have audio heard/understood at a much lower frequency than a digital signal.
Specifically, digital radio is broadcast at around 175Mhz, on the low end; while AM radio is around 1,000 Khz.
HD Radio uses the same frequencies; that’s a selling point.
https://en.wikipedia.org/wiki/HD_Radio
HD Radio (HDR) is a trademark for an in-band on-channel (IBOC) digital radio broadcast technology. HD radio generally simulcasts an existing analog radio station in digital format with less noise and with additional text information. HD Radio is used primarily by AM and FM radio stations in the United States, U.S. Virgin Islands, Canada, Mexico and the Philippines, with a few implementations outside North America.
The term “on channel” is a misnomer because the system actually broadcasts on the ordinarily unused channels adjacent to an existing radio station’s allocation. This leaves the original analog signal intact, allowing enabled receivers to switch between digital and analog as required.
There’s no lower limit to a frequency that contains a digital signal. Submarines use the VLF range and do digital communication.
Any frequency that can transmit an analog signal can also contain a digital signal.
The reason you’d want to use a digital encoding is that it can more-efficiently encode the useful information than an analog AM signal.
AM radio uses a really simple encoding. It’s the analog analog (heh) of PCM, which is what a simple WAV file on a PC uses.
But that’s not actually optimized for a human hearing system, and it’s why we don’t usually use that encoding for most audio transmission today.
PCM is good at encoding whether one sample is suddenly high or low. But…we can’t perceive that. Our hearing system doesn’t pick that up well.
A lot of lossy compression we use – JPEG, MP3, and it looks like HD Radio and the other two – represents data using a discrete cosine transformation (DCT) to obtain data in the frequency domain, as a bit of information in the frequency domain buys more information that we can perceive than PCM.
There’s also a hard line on digital signal interpretation. Once there’s a threshold hit for not picking up enough signal to fully interpret it, you drop straight to getting nothing interpreted
That’s not a requirement of a digital encoding. You can create encodings that deal poorly with interference, but you can also create encodings that deal very well with interference.
If I LZMA-compress my data, loss of a single bit in transmission may result in multiple bits not being recoverable.
Raw PCM is pretty resilient to a single bit error. A bit of transmission lost probably isn’t even perceivable to a human, just because PCM isn’t a very efficient encoding for human hearing.
But I can make an encoding arbitrarily-resillient to interference by using forward error correction to provide redundant data that allows reconstruction of the original data if there is an error in transmission.
Now, that requires more bandwidth, which may not be the tradeoff that I want to make…but using an encoding other than PCM for the audio frees up bandwidth. So if I want to, I can use the bandwidth made available to pack more FEC data in. I can come out ahead in terms of interference resillience if the encoding is an efficient representation.
Single-bit errors aren’t the only type of error out there, and if you know something about the type of interference, you can maybe improve on that – like, maybe you’re more likely to have a run of errors, so you don’t store error-correction data near the data that it’s correcting for. Or maybe I can expend more of my redundant data on more-perceptually-important bits in the data; you can permit for gradual degradation via such a route. As you hit some error rate X, you will be less-likely to be able to reconstruct the more-perceptually-important bits.
The TV was able to interpret whatever signal it did manage to get, even if it wasn’t all of the signal.
ATSC will also be able to show a degraded TV feed – it’s not a flat threshold at which it just cuts out. You’ll start having visual and auditory artifacts, see discolored squares and such.
You definitely can make a digital protocol which is less-resillient to interference than a given analog protocol. But that’s just a matter of the tradeoffs you want to make. That includes how much frequency spectrum you want to allocate to it. What’s important to get correct in the reproduced audio – if you want to reproduce audio for a modem rather than a human listener, then encodings designed for the human are going to do poorly. What the characteristics of the interference you expect to see are. What kind of fidelity you want in a low-interference environment.
Now, that doesn’t mean that a given digital protocol has made the tradeoffs that you want for a particular scenario. But it can.
Also, anything cryptographically secure will be reverse engineered in a few years. If the keys have to be cycled, then all old radios will no longer work.
Loads of examples of DRM being broken (iPhone jailbreaks, Nintendo switch emulators).
How long were DVDs around before they were cracked? 2-3 years?
Nintendo switch emulators came out a year or so after the switch was released.
I disabled the emergency alerts on my phone because my provincial govt was using it like their personal Twitter account, and I can’t stand listening to the radio. I guess I’m going to find out when the tsunami just rolls over me.
but what happens if some event has already occurred which disabled large portions of the cellular network
As someone who has worked as a technician in both broadcast and cellular, I can absolutely confirm that cellular networks are a lot more fragile than any type of traditional broadcast, and that AM is much more robust than any other form of broadcast.
The transmitters are so much more simple devices, and are much easier to repair with limited resources than FM or television, should the need arise.
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
The problem isn’t the energy use nor the cost of the am radio, it’s the amount of shielding and other changes that need to be made so the motor and inverter don’t interfere with the am signal. On my bolt there’s an am radio, there’s some ‘stations’ that I can hear the actual sound of the motor.
