I've got an AM/FM radio that's 20-30 years old and it still works. At some point it would be nice if we could get back to vendor-agnostic wireless protocols that aren't obsolete every 10 years. Until we have such a thing deprecating AM seems premature.
AM is unique in its propagation. It can travel very far very easily and even bounce off the ionosphere in "shortwave" AM situations. It's hard to imagine any form of broadcast radio beating AM at its own game here.
Satellite radio could work, but satellites are a lot more expensive than a radio tower.
It is not about who has been around sooner, or who is more important, but what degrades in the presence of what.
FM is a phase modulation scheme, so random noise is largely discarded, as instead you have a phase tracker tracking frequency modulation.
Basically AM will always have noise, but because of how simple it is unless the frequency is being totally trampled on you can get * something* from it.
FM by contrast will have almost perfect tracking with very low audible noise in the output… right up until the PLL loses tracking and you lose it all.
AM is 530 kHz – 1700 kHz, using 10 kHz spacing
FM is 87.9 MHz to 107.9 Mhz with 200kHz spacing.
IMHO, there are enough AM driver information stations that I would be upset when I eventually learned I couldn't receive them on a car with no AM radio. But it might take several years for that (especially if it's an EV; I'm not taking that into the mountains, probably)
Why not?
Why would you be out of gas in the mountains in the first place? Because you got snowbound and ran the car every couple hours to get some heat out of it.
Nobody in Bumfuck, Nowhere is going to have the tools or technicians to try to repair an EV. It will likely be a long and expensive tow to somewhere that does.
> Because you got snowbound and ran the car every couple hours to get some heat out of it.
Complete tangent, but how do EVs handle low-traction surfaces? Seems like they might do better on average from the weight, but that’s a wild guess on my part.
The real danger on highways is traction control. It can hide how slippery the road is and allows you to easily outrun your braking ability.
In the northern Midwest, you’ll see car after car in the ditch when it hasn’t snowed in a while.
As for people forgetting how to drive in the snow over the summer? That seems to be universal. Seen it in Ohio, Massachusetts, Vermont, and New Hampshire.
I can take gas cans to enhance range of an ICE, if conditions are marginal. There's no way to enhance the range of an EV.
exclusive of digital modes, the most distance effective signal is CW. unmodulated signal, on or off.
AM uses a significantly lower frequency and ground wave propagation is much more likely which gives AM the benefit of being able to reach "over the horizon" where FM simply cannot.
I wonder if the car manufacturers could get around this by offering free handheld AM radios? In bulk, they probably cost less than $10.
Why? It not ought to be if you know what you are doing!
It seems a great shame that universities don't teach electromagnetic shielding and screening in digital electronics, or if they do they only gloss over it. Once it was a core subject and everyone understood its importance. Moreover, the failure to teach EMR shielding techniques in 101 electrical engineering has been an ongoing saga for decades, it's why digital people end up with little or no concept of the issues that confront engineering in the small-signal analog world.
This lack of training and the failure to emphasize the importance of proper spectrum management, which, in short, is the science of using RF frequencies efficiently without causing interference, is the principal reason why digital people don't seem to give a damn about the RF/EMR pollution and noise emitted from their switching circuits. Now opportunistic EV manufactures have the damned hide to try to sweep away the last vestiges of prudent spectrum management.
Fact: if you cannot listen to a normal broadcast AM radio transmission within its authorized service area on a car radio then the EV's electronics is polluting and radiating noise beyond normal acceptable limits. QED.
One sees crappy almost non-existent shielding everywhere from domestic electronics through to huge Tesla coils that completely block out swathes of radio spectrum for many tens of kilometres. Under ITU and national spectrum management laws such behavior is supposed to unlawful but no one including the FCC does anything of consequence about it (once if you emitted radio noise you'd soon find radio inspectors clambering all over your equipment with RF noise detectors).
Over the past 40 or so years the electromagnetic spectrum, especially HF frequencies, has, in parts, become almost unworkable because of crappy noise from digital electronics and the principal polluters are those in the digital electronics world. Let's be clear what we are talking about here: they are polluters and it's pollution like any other green issue—think of oil spills, chemical residues, nuclear waste, now add to that list electromagnetic pollution.
About 20 years back NATO did a report that indicated the background noise floor on the HF spectrum had been raised by about 6 to 8dB because of unwanted electrical noise. Several years back at a SMPTE engineering exhibition I quoted this figure to the chief engineer of a manufacturer of HF transmitters and he looked at me with surprise and asked where had I been in recent years, he then informed me that the then current noise figure had risen to about 17dB!
That level of EMR pollution is outrageous, it's clear that parts of the RF electromagnetic spectrum are already unusable.
Imagine how bad the EMR pollination will be if these bastard EV manufactures get their way and when there are millions of EVs on the road without adequate EMR suppression. Not only will all long wave, AM and HF bands be unusable but so too will large sections of the VHF band.
For those who don't understand the problem let me put it into perspective. These EMR shielding problems were solved in the 1930s when aircraft used HF radio (≈3-30MHz). Aircraft HF radio receivers have to be about an order of magnitude more sensitive than normal domestic AM radios because the incoming signals are so much weaker. That didn't deter RF engineers of the day, now all aircraft electronics are properly shielded.
So what's wrong with the EV engineers? It seems to me it's a combination of cost-cutting and ignorance.
This law must succeed!
__
A few basic references for the untrained:
MIT Radiation Laboratory Series vol 23 - Microwave Receivers, Ed: S.N. Van Voorhis, 1948.
Noise Reduction Techniques in Electronic Systems, Ott, Henry. W, 1976, Wiley.
Thanks for the history, precedents and references.
Well, back then radio inspectors didn't have to fear getting shot.
Snark aside: it's only getting worse every day. Temu, Wish, Alibaba, Amazon dropshippers - almost none of the stuff they sell has passed any kind of compliance audits, and they aren't even required if the device in question isn't intended to participate in RF communication. That is the real culprit... all these billions upon billions of small devices with high frequency voltage regulators that all act as (very) tiny RF emitters.
And even if you'd begin to teach about shielding and EM suppression in electronics design courses, it would be pretty useless against the infamous magics of "gongkai". Just look at this $12 phone [1] - no RF shielding anywhere despite the thing literally being a cellphone. And yet if I were to order one of these, even an entire batch, chances are high no one would ever stop me.
[1] https://www.bunniestudios.com/blog/the-12-gongkai-phone/
True, but as I just posted to buescher we, as a society, will have to rethink the EMI problem and this will change the whole approach to electrical engineering per se. Protecting the electromagnetic spectrum will need to be considered of paramount importance (as our communications infrastructure depends on protecting it).
Like chemical engineers, considering the effects of EMI pollution levels will have to become the first step in any electrical/electronic project.
This also means tighter regulation and possibly new laws.
I wouldn't be that sure.
Yes, there is a lot of garbage and congestion on the spectrum, but thanks to new approaches to (forward) error correction, higher quality RF parts and especially the explosion of compute power, we can achieve ridiculous communication quality. And it's not new either - GPS is orders of magnitude below the noise floor, and yet, we got "smart collars" for cats and even birds capable of decoding that signal.
Pretty much the only ones who actually have a problem with all the garbage are hams, and to a lesser extent air traffic control (for them, it's mostly people with garbage handheld radios, and dumb pilots not switching from ATC to onboard communications).
Agreed, but that noise can be contained with an effective Faraday screening.
If noise escapes then the shielding isn't working properly.
It seems to me that electrical engineers—especially those working in high speed digital electronics—need to think like chemical engineers who spend much of their time in the containment business. Safely containing dangerous polluting liquids and gasses is a basic premise in chemistry. Most of the engineering infrastructure of large chemical plants is involved with containing chemicals and doing so in ways that are safe and do not pollute the environment.
On the other hand, electrical engineers have a dangerous waste product—EMI—that they'd rather forget about. Well, I suggest that in today's world that thinking is just not good enough.
Put another way, when building electrical/electronic systems start with the foundation which is to ask what pollution or damage will this project cause. The first question is to ask yourselves what are the shielding/EMR requirements for this project. Chemical and civil engineers start with such requirements as a matter of form and good practice. So should electrical engineers (you do this now re electrical safety, so you just have to extend that thinking to RFI).
It's now time electrical engineers started to work in the same way. RF shielding and protecting the electromagnetic spectrum should no longer be considered an inconvenience and afterthought but as a major component of the project.
BTW, by adopting good shielding practices you'll be preparing yourselves for the next Carrington Event. Remember RF shielding works both ways—in and out!
I don’t think car manufacturers are saying they don’t know how to shield, they’re saying it would come at a cost:
"Requiring the installation of analog AM radios in automobiles is an unnecessary action that would impact EV range, efficiency and affordability at a critical moment of accelerating adoption," -the fine article
I smell short-term thinking here and concern over their current problem of falling profits from EVs
Cellular, WiFi, and Bluetooth are vendor-agnostic. The issue is there's finite radio bandwidth and because the radios are vendor-agnostic they all need to built to a specification. Interop between cellular basebands made by a variety of players and base stations made by yet more players is already a minor technological miracle.
Old AMPS phones want to use the bands carriers moved to 4G/5G service. There's no affordance for backwards compatibility because the old technology was just shittier. The bandwidth of a single AMPS phone can now carry many dozens of 5G connections and provide them with full service.
If you want to goof with electronics in your garage the only person you're going to affect is yourself. When you start messing with radios, the emissions are invisible. You don't necessarily realize you just raised the noise floor for your whole neighborhood. It's pretty easy to build a device that barely functions as a radio but works really well as a jamming device.
The analogy to the Internet I'm making is this: yes, the protocols are open and you can theoretically participate with "the Internet" using even a potato, as long as it speaks TCP/IP. This is the decentralized, packet-switching, "routing around censorship" part. It's also not the part that matters - the actual Internet is the application layer, and it's in large part centralized in entities like Meta, Google (and on a different dimension, Cloudflare). Packet switching won't help your Facebook page to "route around censorship" when Meta itself is the censor.
To do anything on cellular bands requires a license. Consumer equipment is locked down to get type licenses. Carriers need their own separate licenses from the FCC or local equivalent. You can build your own basebands but you can't do anything without a license. No carrier, paying for licenses and operating the network, is going to freely connect you to their infrastructure. People have collectively decided cellular networks is more valuable/useful to modern society than being able to goof around with scratch built cellular radios. There's other bands open to experimentation (ISM).
Complaining about Google and Meta is likewise confusing. Meta and Google can censor whatever they like. They don't owe you a bullhorn. But they do not control the whole Internet. If you can get packets routing to you, you can still publish whatever content you want. You can build your own application layer completely ignoring Google and Meta. There's dozens of overlay networks built on top of base Internet routing that work just fine.
I'm just saying as far as service level and amount of data on plans, I personally was content with 3G levels. There's so much advertising pushing us into churning for technolust incrementalist spec-chasing, that I find completely uncompelling as what really defines my devices' capabilities is software freedom.
This is what I think may be the source of confusion, since you can’t say, build your own cellar device and tap into Verizon’s network without their authorization, like you can with AM or FM radio waves
Just because AM is easy to transmit or receive in any band, doesn’t mean you’re allowed to.
The matter reminds me a bit of copyright law about 40 years ago, back then the GP was hardly aware that copyright existed, nowadays it may not be much the wiser but it at least knows one can't just copy works without permission.
EMI and spectrum management is in a similar position to copyright of 40 years ago. It will be a long slow process to bring the GP up to speed. First we have to begin training electrical engineers in the subject as at present only a handful actually understand the subject at any depth.
For now I'm enjoying the free satelite radio trial.
Right, it's really a damn nuisance. I want to change the radio and it's nigh on impossible.
You could make the argument that "physical buttons are safer," but that doesn't mean the UI that accompanied these buttons was that great.
Most vehicles pre-touchscreen had vehicle control functions on shitty jog wheels or arrow buttons on the steering wheel (maybe with a 7 segment display, maybe an LCD.)
Bonus: Zero political anything to worry about. The weather radio is a completely boring readout of the weather and alerts. It’s simple. It’s beautiful.
It would be trivial to support with most existing FM antennas anyways, it already supports national emergency announcements in addition to weather alerts. It even broadcasts a signal telling you where a given alert is targeting. A vehicle could use and correlate its GPS location to notify occupants.
AM would require manually switching the radio mode, tuning to find an appropriate channel, and there’s so much crap to dig around.
Plus, say a nuclear weapon went off anyways and all the FM transmitters died. Is anyone seriously thinking a lone AM transmitter 2000 miles away is going to help? We had all the communication in the world during COVID and that did nothing to stop people from acting foolish.
It's not for me to explain why in detail here but AM radio communications is the best value for money of any communications system outside of telegraphy (wired or wireless). It's cheap, simple, easy to construct, and it's scalable to any size (and transmission distance) that's needed.
AM radio is one of the greatest inventions of the 20th Century and it's far from outdated.
Come the Bomb and or next war and if you have any communications at all then it will almost certainly be AM Radio.
AM Radio can be local or long distance and cover the world depending on frequency. Years ago during a sunspot maxima, I watched a friend of mine located in NSW Australia talk to someone in California on 27MHz AM using only three watts of power (from a handheld CB radio) and using only a whip antenna.
I defy you or anyone to come up with a simper technology that can do that. If you want to cover say the continental US with radio during, say, a national emergency when nothing else works then it'll be AM radio that comes to the rescue. This simply is why AM radios ought to be made mandatory in every vehicle.
This is not even an argument, it's a no-brainer.
The amateur radio operators who are preparing to maintain communications "come the bomb" are moving in droves to modern digital modes, because of the huge advantages in weak signal performance - likewise for military and public safety radio. If you want to get a message through in tough conditions, it's a no-brainer to use a highly efficient modulation scheme with error correction.
AM receivers are widely available for legacy reasons, but that's about the only thing in AM's favour.
Exactly, it seems the present generation is unfamiliar with the way traditional AM radio works. It's really worrying, as it demonstrates how very easily knowledge can be lost across only just a few generations.
The point I was making is that AM is not only simple (a crystal set/germanium diode will demodulate it) but more importantly it is the 100+ years of experience and especially the huge amount of existing AM infrastructure throughout the world including millions of car radios—including those in undeveloped countries which is important—that are key to why there's a push to maintain the service through legislation. I've already made comments to that effect in other posts so I'll leave it at that.
Second, I agree with your point here about digital signals and the ionosphere. Similarly, it's why I'm a great fan of Digital Radio Mondiale (DRM—badly named given its other meaning).
In fact, I'm upset and rather annoyed that it receives so little attention and that it's made so little penetration into HF bands but there's little I can do about it except whinge.
Unfortunately, just because something is good or better doesn't mean it gets adopted (remember VHS won out over Betamax although the latter was better, also Windows versus Linux is another comparable case). If you look at history often technical standards (and improved methods) are adopted after the event. Also, grandfathering technology is commonplace whether we like it or not. I learned this years ago when sitting on several preparatory committees for WARC/WRC and also when involved with television standards for industrial work. Things that make obvious sense technically often don't get up because of political and economic considerations—and stubbornness by those with entrenched views. It's a big problem (arguments over standards are common, are often heated, and invariably messy—and often the outcomes end up overly compromised).
That brings me back to my earlier point about AM, other systems are better but other factors stop them from being universally adopted.
> it's a no-brainer to use a highly efficient modulation scheme with error correction.
And an audio codec with a good ecc scheme on top. You can shove huge amounts of data into the AM spectrum, there's no reason it should be filled with pops and fizzes.
What have said that's factually incorrect (please be specific)?
Why is AM is incredibly inefficient?
People used AM very effectively throughout the 20th Century to communicate around the world. My example of communicating half way around the world on three watts of AM is hardly inefficient. Frankly, it's truly remarkable.
What I was talking about had nothing to do with modulation schemes. It had to do with the ease and practicability of AM radio especially when technical support infrastructure is minimal and that includes expertise/technical personnel (there many no be any in certain emergencies).
Incidentally, digital modes have their place and I've no argument with that, but I'd take issue with your broad statement about "the huge advantages in weak signal performance". Would you explain precisely what you mean? The info in your links isn't helpful here.
BTW, I got my amateur ticket when I was 15 in high school many decades ago, I'm very familiar with how the amateur movement works and with the tech that we use.
This:
"AM radio communications is the best value for money of any communications system outside of telegraphy (wired or wireless). It's cheap, simple, easy to construct, and it's scalable to any size (and transmission distance) that's needed."
AM is technically simple, but it isn't cheap, practically simple or easy to construct. You need to throw an enormous amount of power into the air relative to a more efficient mode, which means big transmitters, big masts, big power bills, big repair costs. AM broadcast stations are being closed down at a rapid rate because they're very expensive to run and maintain. That infrastructure is inherently vulnerable to whatever end-of-the-world scenario you might be worried about.
You can get a very long distance contact on AM, but you need good propagation conditions and a great deal of luck; a suitable digital mode will do that on a long wire hanging out of an apartment window during a solar minimum.
>Why is AM is incredibly inefficient?
The carrier signal and half the sideband is completely wasted power, hence SSB. The majority of the power going into your antenna carries no information whatsoever, it just compensates for the crudeness of the receiver. With AM there is a 1:1 relationship between the SNR at RF and baseband; the only way to overcome noise local to the receiver is to throw a louder signal out of the transmitter.
Even FM has an advantage here, but a digital mode can operate on incredibly tight SNR margins. The modulation scheme can run pretty close to the Shannon-Hartley limit, and (if you need voice) you can drastically reduce your data rate with a good voice codec. If you don't need voice, then you can use a very data rate and work on incredibly low (or even substantially negative) SNR. Spectral efficiency and power efficiency are two sides of the same coin.
As I said in my original comment, AM receivers are commonplace, but that's the only thing going in AM's favour. If we were to design a communications system of last resort today, there are a multitude of better options. Relying on the existing AM broadcast infrastructure for emergency communications is mostly wishful thinking if you compare that to a really serious system like Japan's J-alert.
Thanks, you're correct. And as I've said elsewhere that's why it's being mandated.
https://en.wikipedia.org/wiki/Minot_train_derailment
> The Minot train derailment occurred just west of Minot, North Dakota, United States, on January 18, 2002, when a Canadian Pacific Railway freight train derailed, spreading ammonia gas across the city, delaying rescue operations. The cause was found to be small fatigue cracks in the rails and joint bars, not detectable by the inspection routines then enforced by Canadian Pacific.
[snip]
> Because it was the middle of the night, there were few people at local radio stations, all operated by Clear Channel with mostly automated programming. No formal emergency warnings were issued for several hours while Minot officials located station managers at home. North Dakota's public radio network, Prairie Public Broadcasting, was notified and did broadcast warnings to citizens.
And Minot is one of the bigger cities in North Dakota.
Agreed, it's a serious issue, and the first thing one notices about prerecorded and netwoked programs is the lack of spontaneity and liveliness of the content (personally I don't like stations that are run like this).
This, of course, is a regulatory matter. There's no reason why programs cannot be interrupted by an actual human in such emergencies, even if not a professional announcer, an emergency worker or police perhaps.
I do not, however find that to be a compelling argument for mandating its inclusion in cars. While market forces may be inadequate for driving crash safety, emissions, or fuel economy standards, they seem very well-suited to determining whether cars include AM radios. I suspect the answer will be that most car buyers don't care, and a cheap portable receiver is an adequate solution for many who do.
Even if you never use the AM radio in your car someday someone else may do so to get emergency info (it has a much longer range than FM).
BTW, most of my radio experience has been in FM broadcasting, so I'd naturally choose that as a better quality broadcast medium. But we're not talking about that here, but rather the fact that AM radio is the LCD for a multitude of reasons.
Incidentally, I've also worked on the transmission side of television and I've been involved with spectrum management from a policy perspective. What I've notice in these posts is the tendency to dismiss AM simply because people have become unfamiliar with it given the many media options available today.
What people forget or have never understood is that to get that high quality video and sound on your smartphone, or on your widescreen OLED TV requires a huge amount of very complex infrastructure, and it takes many people and many organizations to do so. Only the slightest thing has to go wrong and the whole edifice will come crashing down. An idiot, terrorist and or natural disaster can kill it in an instant, whereas the low tech widely distributed AM TX network is much, much harder to bring to a halt. We saw this on many occasions in WWII, there were many instances where cities were left in ruins but the AM broadcast from those cities were either left intact or gotten up and running again within only a few hours. Again, that's what this whole discussion is about and why AM car radios are being mandated.
As I mentioned elsewhere, heaven help us come the next Carrington Event (which it will), none of that lovely media infrastructure will be left standing. Similar scenarios can result for certain emergency situations. When all communications fail then AM radio will be by far the easiest to reestablish, and with millions of cars having an AM receiver that will have services up and running much faster.
I know AM is not fashionable but it works and it's easy to establish, same can be said for sewer pipes but we don't chuck them away because they're not fashionable or because they're low tech.
This, simply, isn't the issue.
Honestly, in my 35+ years of driving, I've used CB/FRS way more often than AM.
I'm not sure AM has the same issues
2 MHz 200-400 miles
4 MHz 400-600 miles
6 MHz 600-1,200 miles
8 MHz 800-1,600 miles
12 MHz 1,200-2,400 miles
16 MHz 1,600-3,200 miles
22 MHz 2,200-4,000 miles plus
26 MHz unpredictable during our solar cycle minimumTrue, except when the ionosphere is changing rapidly and phases change across the bandwidth (as in fading). SSB helps and it's really great for narrow band comms but without the carrier the demodulated audio has pitch problems. Not an issue for basic comms but it is if audio has to be on frequency.
SSB reduced carrier and synchronous detection is another solution.
I went out and bought a radio in case that awful day comes.
This example makes me think that these wavelengths will be heavily congested in the event of a major global, or even local, disaster.
I imagine this would depend on who can transmit "louder"? In the case of a disaster, that would likely be emergency services of some kind
This is an interesting assertion. Many, many people acted responsibly during the pandemic, and in a worst case scenario such as what you described, it's even more likely that a sizable population will gravitate to any source of reliable information.
The government is usually the source of last resort for many, many things. Whether it's as a lender (e.g bailouts) or as a source of information (emergency broadcasts), it's at the scope of the nation state where extreme contingencies exist and must be accounted for. I imagine AM radio is perfect for this precisely for worst-cases, e.g where someone might seek to make a crystal radio, but I'd be out of my depth thinking beyond this.
I actually was neutral on this until I read your comment and thought it through far enough to reply, so thanks for that.
Most people I know do not have a short-wave radio, let alone one capable of receiving at 162Mhz.
It was because a chemical truck crashed apparently, on our drive back home it was still there with specialized hazmat emergency vehicles around.
More or less all US car owners already own a VHF radio. Extending it from 88-108MHz up to 162MHz would be fairly trivial.
The modulation scheme is not the reason for propagating around mountains and bouncing off the ionosphere at night. The reason for that behaviour is the low frequency used. 540 Kilo-herz to ~1700 Kilo-herz. (I was told once by a young engineering colleague that 1,000 Khz was not RF. :-))) )
So the question is valid. FM could be used in the "middle-wave" band. It would reduce noise but might suffer more when bouncing off the ionosphere at night. (I have read this but never heard FM bounced)
The reason FM is not used in the middle-wave band is legacy regulation not technology.
Narrow band FM is used for aircraft. police, fire, amateur radio communication and since 2021 it's even legal for CB radio in the USA. It's deviation is limited by law to about +/-2.5KHz, from centre frequency.
Setting up the modulation depth on an a broadcast FM exciter, I have used a spectrum analyzer and Bessel function information to make sure it was legal.
I've alluded to this elsewhere. As I mentioned, RF/RFI and spectrum management subjects have been downgraded or reduced in electrical engineering courses just about everywhere so it's little wonder we've problem.
FM by comparison is effectively line of sight, so with a practical broadcast antenna the upper limit is 40 or 50 miles.
And I should clarify… while it was certainly a cheap “system in a box”, it was a real multi component system with detachable speakers, etc. not a boombox or anything like that.
AM is more spectrally efficient than FM, and with synchronous AM receivers, you can get noise rejection that is near FM.
I live in an area like that as well, and the station broadcasts the same info you see on road signs and web sites. If the lights are flashing it's usually playing "snow tires advised for vehicles..." on loop.
the kind of situations people describe where car AM radio is essential feel like corner cases that involve lack of planning and poor judgment or really bad luck. No cell service, no portable radio in your travel kit, no way to stop and ask anyone, and you can't just turn around when you see a flashing sign? It sounds like the plot of a horror movie.
Thing about corner cases is they do exist and need to be accounted for
This is a problem solved by a $10 Amazon purchase. Why is it such a crisis for you?
Personally I think it’s pretty ridiculous for cars to be removing it and it’s taking a law to force them to keep am radio
But that’s besides my point
Would having each new car come with a portable AM radio in the glove box be an acceptable solution? What if car AM came locked to an emergency government frequency?
From my perspective we're looking at broadcasters cooking up culture war so they don't have to negotiate with the auto industry to keep their business running, and the end result will just be increased car prices for everyone.
AM radio is simple enough to build with makeshift materials (https://en.wikipedia.org/wiki/Foxhole_radio). You don't need batteries or even a power source at all! (the radio waves themselves can bring power)
If civilization had a catastrophic event, I would guess that AM radios would be one of the few surviving technologies
The main problem is that this requires that thousands of radio stations continue to operate, where a single AM station can provide service to multiple metro regions and in many cases cover an entire state.
It would be even better if car radios were required to include shortwave / SSB receivers, but there is little mechanism to support the economic ecosystem that would keep those stations viable, and the radios are necessarily more expensive. The long range of shortwave would also open up US listening populations to potential foreign adversaries.
AM is a good compromise. AM recovers are cheap and simple, transmitters can be made using 1920s tech, and A single AM broadcast station can have ranges of nearly 1000 miles, sometimes more.
On a related note, the Federal government has primary rights to 1710 KHz, but it's rarely used, and available on most radios. I think three or four high power 1710 stations, synchronized in the decentralized way that WWVH and WWVB are, would be an excellent use of a narrow slice of spectrum, particularly as a way to disseminate information after sunset.
The government has took away our (the taxpayers) right to move for the sake of some taxpayer's life. How on Earth is possible for the taxpayer to act foolishly? It is his life, if he considers a death as not that important thing to cancel some party, whether it can be considered as foolish? My opinion is that a human has to have a right to get dead, no matter how much taxes the government is going to not take.
You can receive AM with very simple receivers. The cost of adding one to a car is miniscule, and it works when other more complex systems don't.
Not only emergency broadcasts but things like https://en.wikipedia.org/wiki/Travelers%27_information_stati... make it important to have a working AM radio in your car.
This story was the one that came to mind when I say your comment and the post makes for a quick, interesting read.
https://www.snopes.com/fact-check/lucille-ball-fillings-spie...
The video looks convincing but it could also be faked, and I don't think it's possible. The signal coming into the radio tower (which is basically just a big antenna) would already be modulated to a much higher frequency (702khz or whatever).
I guess there could be some other effect that makes it audible when you hold a blade of grass or a hotdog to the transmitter, but I don't think it would be intuitive.
I don't think it's faked, what's shown here is what you'd expect. I've been on 'live' FM towers and the RF burned holes in my jeans at my knees (my knees were rapped around the metal tower and the induced RF in the tower zapped holes through the material in my jeans and then burned holes in my skin).
On AM the sound that you're hearing is demodulation caused by resistive non-lineararity in the carbon caused by the burning/heating process. This is quite a common phenomenon with high powered AM transmitters.
I thought I was going cracy when turning the volume to zero did not cut it before I realized it was radio hehe.
Maybe there can be accidental demodulation somehow?
AM is just power, its why crystal radios work...
(the wire is optional if the signal is strong, and a 'headphone' is anything you can make vibrate with electricity)
> Whatever the case may be, the available evidence behind this tale appears to be purely anecdotal and not verifiable at this point.
It's sort of like clickbaiting doctors when they read "doctors don't know what causes obesity!".
https://en.wikipedia.org/wiki/Minot_train_derailment
> The Minot train derailment occurred just west of Minot, North Dakota, United States, on January 18, 2002, when a Canadian Pacific Railway freight train derailed, spreading ammonia gas across the city, delaying rescue operations. The cause was found to be small fatigue cracks in the rails and joint bars, not detectable by the inspection routines then enforced by Canadian Pacific.
[snip]
> Because it was the middle of the night, there were few people at local radio stations, all operated by Clear Channel with mostly automated programming. No formal emergency warnings were issued for several hours while Minot officials located station managers at home. North Dakota's public radio network, Prairie Public Broadcasting, was notified and did broadcast warnings to citizens.
And Minot is one of the bigger cities in North Dakota.
[citation needed]
There's a Grand Canyon between putting in an AM radio circuit and putting in a fully functional AM radio, doing over the vehicle's EMF, and then making it last for a vehicle's lifetime.
https://www.markey.senate.gov/imo/media/doc/letters_of_autom...
"Our decision to not support AM radio was primarily linked to our electrification strategy. If Volvo Cars had continued to provide AM radio, our BEVs and PHEVs likely would have experienced EMC disturbances and this could result in poor performance. "
Why must all cars have AM radio?
Then we'll get a bunch of people who are either ignorant of the conditions or who are fumbling with their phones trying to find the information on the internet somehow.
We could phase in a new traveler information system that works in new cars, but that would require an enormous expenditure of resources to roll out the new system and then we'd have to maintain the old one for as long as there are vehicles on the road that don't support the new. It's far more cost effective to just mandate that all vehicles be able to receive signals from our existing system.
Electrical vehicles' switching power supplies are terrible radiators of low frequency radio. As the articles say, this radio interference is why auto-makers were removing AM radio. If this regulation passes to law it will have the unintended effect of making auto makers not pollute the entire world's shared radio spectrum and prevent it's use by all. The FCC should have stepped in to bar production of many of these vehicles but I guess congress has it accidentally covered. We can only hope that other nations pass similar legislation.
It is entirely possible to minimize and mitigate these conducted and radiated emissions. It will just mean hiring RF/Power EEs to know where to put the caps, how to run a controlled impedance line, etc.
Diesel engines don’t produce such electronic noise — hence why they’re used in radio quiet zones.
It seems it would be for most situations. If it's emergency info, everyone would need to hear it. Most roads either don't have a shoulder (rural, semi rural), or have too high of a volume for the shoulder to handle all the traffic (multilane highways, city streets). Even if the stops were temporary, you'd end up with massive traffic jams that would likely make any emergency worse.
But I don't think the lemon law allows for work around anyways - you bought a car that is (will be) required by law to have AM radio, and that feature does not function when driving the car.
Just keep kicking the can until the last ~4k AM stations in the US close.
I've been exploring the AM dial since this issue first arose a year or two ago. So far, the furthest transmission I've knowingly received was a station in Chicago while I was in NW Connecticut. I've also heard of people in the NE US receiving transmissions from Central America and Europe, especially at night (the sun causes some amount of interference).
You may protest that you can FM at 1 Mhz and get the range boost on a much nicer sounding signal but:
- FM isnt as efficient as AM and 1 Mhz isnt a lot of space
- FM "locks in" to a station, partially what makes it sound so good. On AM you hear everything and its "up to you" to figure it out; meaning the intended signal is there and you might be able to squeeze meaning out of it (since you know a lot about it). On FM if the receiver cant "lock in" or locks into another station you cant receive any information.
That last point is also why morse code is so reliable - a human operator can very easily distinguish a sine in noise
In the event of needing to communicate in an emergency you must assume that the right ionospheric conditions will not be present and that you are limited to line of sight.
In other words: you really don't need the ability to sometimes unreliably broadcast icy road conditions, or a tornado alert, to someone three states away.
I can't imagine choosing between two cars and picking one because of its AM radio reception. I wouldn't even make a bet that I know if my car can receive AM.
Between the standard AM radio content and the availability of better options like streamed audio, I just don’t see people caring.
Until and unless an emergency does happen, in which case, they’d have to actively know to tune in (unlikely) and have to not want to pull over to listen.
They’d also have to be in a situation where the other emergency broadcast tools on their phones don’t work.
I just don’t see it being anything that any number of consumers would care about, beyond the standard number of outliers that are usually accounted for.
I think the latter is significantly more likely.
Reducing EMI down at medium wave from motor drives is really, really hard. Filter networks that keep most of the switching frequency out of the motor and motor wiring are big, cost money, and reduce efficiency.
I know nothing about the technicalities of why this specific EMI is hard to eliminate, so I'm asking an honest question. Why? What makes it difficult to block this EMI? Where is it being generated (I'm assuming the motor windings??)? Is there not some sort of cage that can be built around the motors by lining the wheel wells to block the EMI?
It’s already below FCC limits for unintended radiation - it’s not going to block AM activity far from the vehicle, but putting the antenna in the midst of all that radiated noise is challenging.
When things are brand new and in good condition, yes, probably.
The motor controller is turning the motor on and off rapidly in this frequency range to control the power in each winding. The inductance of the motor converts this to a near-constant amount of power.
> cage that can be built around the motors
The motors already have shielding and the wiring does, too. But when every car has peak RF output of hundreds of kilowatts, not too much of a fraction has to leak out to completely jam the AM band.
90% of AM radio stations are owned by ~5 companies pushing a conservative agenda, with a similar disparity in programming (i.e., 90% conservative).
Most of the 10% of non-conservative stations are in progressive markets, where they have little impact. E.g., in San Francisco, the programming split is ~70/30% conservative/liberal.
Here's the (admittedly biased) source, but the numbers would be easily rebutted if untrue:
https://www.americanprogress.org/article/talk-radio-by-the-n...
AM radio licenses are a fixed government monopoly, and it's well within the budget of political organizations to subsidize a radio station, so there will be no change in this disparity driven by market solutions.
Assuming the numbers are true, once government policy results in an enduring political bias in media, does the government have any responsibility to mitigate that bias?
Does the government have any obligation or even mandate to reach into product design and require certain features - features unrelated to safety, pollution, energy, or any other generally accepted social good?
This is a bipartisan bill protecting the government's ability to transmit emergency notices on what is inarguably the best available technology to do it.
Saving lives takes precedence over your political identity, I hope. Thankfully both sides of the Senate think so.
I'm glad you weren't involved in their decision. You seem to have lost sight of what's important.
Why not NOAA? Because existing signage is already in place for the current spectrum arrangement.
Now we have to replace signage across 50 states? No thanks. I don't listen to AM radio. You don't either.
Why do you care?
Calling someone skeptical of Republican motives a mindless zealot is... Zealous.
If it were midnight and a Republican told me the sky was dark, I wouldn't say it's bright out. But I'd take a peek to check. There is not good faith to be had with that party.
Skepticism is fine. Killing people because you "doubt the other party" has no place in society.
That kind of decision making, that ignores safety, should more rightly be met with jail time, not leadership in a democracy.
Thankfully for the rest of us, both parties can see that.
If the Left pushed to rearrange the band and won, then there would be something to criticize. Now we have to redo signage? Or we're all less safe? For what? To silence a handful of people? To give the automaker lobby a win by saving $5 per a car? I doubt they care so much.
The Left has no reason to do anything other than what they did. Approve it.
If I were in Congress, strictly from a technical standpoint, I'd be ambivalent before knowing more about cost.
Your "If the Left" analogy is silly. The "Left" isn't pushing to eliminate AM radio. It was deemed incompatible with EVs and the market was making a decision.
I didn't say they were. You're making a straw man argument. I literally said the opposite, that they agreed with Republicans in protecting the safety of Americans.
> I question your claim that presecing AM radio in EVs costs only $5
I'll double down on that point. The radio retails, shipped, for $9. [1] Those are consumer prices on individual, discrete units, with additional plastics, documentation, packaging, separate warehousing costs, freight, etc.
It's obviously much cheaper than $5. I've grossly overestimated the cost of an AM radio.
[1]. https://www.amazon.com/Portable-Pocket-Compact-Transistor-Ra...
(Especially, the winner should be allowed to run eg better wifi on them, or better mobile phone data.)
And Ed Markey is not exactly a conservative politician.
But that brings up a bigger problem, many many radio stations are essentially on autopilot or run from a distance without the ability to address local situations. Without support for truly local stations, AM radio may be present, but generally without significant value.
What you're saying is that it's a useful backup for a service that remains imperfect. But if you had to pick just one emergency notification technology for the modern world, it would be mobile telephones. There's really no significant argument there.
Definitely disagree. Mobile phones have a million failure modes. The only reason I'd choose them is 2-way communication, not reliability of 1-way communication.
Sorry, there is more to reliability analysis than just analyzing failure modes. Whether or not a technology is productively useful for its intended purpose is important!
What does it mean?
> many users don't know how to use the ones they own.
Who are these people that don't even know how to turn on a radio and turn a knob?
This legislation is absolutely out of touch with reality, and will do nothing but allow the old guard to slow down innovation and force the past on people who have no interest in it and will receive no value from.
AM is the simplest mode of communication and one of the reason air traffic controllers still use AM rather than FM or digital codecs for communications.
AM is great for emergencies so put a wind up in your emergency kit. If, for some reason, you need to take it to your car then go ahead. Want one at home and one in your car? Go nuts.
I say this as someone who generally dislikes cars and wishes our infrastructure was designed to make them less necessary. They are great in emergencies and decreased car ownership does mean having to make up the slack in emergency preparedness in other areas.
If a lot of people having cars is just a convenient place to distribute emergency radios then require they come with said portable radio next to the spare, don't require the car itself to have it.
I absolutely think that having an emergency radio is better preparation that relying on your car. However the inclusion requirement makes sense. It is rare that a group of people will be isolated with without a vehicle and ensuring every vehicle has an AM radio is the best way of ensuring everyone has access to one in an emergency.
If you can get into someone else's functioning vehicle you can also get to the one mandated to be in the trunk instead, where the radio is guaranteed to work without actually being able to start the car too.
Are trying to be silly? I'm much more concerned about drivers having access during a bizzard, earthquake, mudslide, forest fire or any of the other regularly encountered hazards about which AM radio is used to communicate with drivers.
> If you can get into someone else's functioning vehicle you can also get to the one mandated to be in the trunk instead,
An item physically attached to the vehicle is much more likely to be there.
If you think mandating emergency radios is good, then go for it. Let's wait to see how well that plan works before removing a standard piece of safety equipment that has worked well for decades.
The only time AM is relevant is when the _ENTIRE_ radio communication infrastructure except AM is unusable due to the disaster, such as after a hurricane or in nuclear war, and in those cases you don't urgently need the alert while driving down the highway.
If you can't defend new regulation as worthwhile beyond "we, by happenstance, typically had it before so we should keep doing that" then you've failed to defend the new regulation. It either makes sense and should be done properly because of actual safety reasons or it isn't worth doing half assed and inconveniently just because it used to be a possibility.
I'm a huge fan of regulation, especially around safety, but only when it targets the actual goal directly. If the goal is "you must guarantee that a vehicle is sold with a way to receive EAS communications from at least x miles away" then make that the regulation and let manufacturers choose if that's a built in AM radio or not, don't just regulate "all cars must have AM radio" as you've just locked things into being the low quality solution until it becomes a big enough issue to actually go make a whole new federal law about it.
EAS is also much more limited than an AM station as is designed mostly for national level emergencies. It has limited ability to update it's message as the situation evolves and doesn't work at all for low level emergencies. EAS works great for nuclear war but not at all for a landside that makes a road impassable.
> The only time AM is relevant is when the _ENTIRE_ radio communication infrastructure except AM is unusable due to the disaster
This is simply false. I use AM regularly to check driving related alerts.
> If you can't defend new regulation as worthwhile beyond "we, by happenstance, typically had it before so we should keep doing that" then you've failed to defend the new regulation.
We have an existing system of AM emergency information that works well because every car has an station. It won't work in cars don't have AM radios. If you want to change the status quo, you need to demonstrate that you are already solving those issues in a new way. I'm all for findign a better solution here, but it has to be rolled out first.
> If the goal is "you must guarantee that a vehicle is sold with a way to receive EAS communications from at least x miles away"
First off, that isn't the goal. Secondly, that would be a horrible regulation that would be hard to test given how radio waves work with terrain. Generally reception has far more to do with location than it does with hardware ( at the antenna scale under discussion). Thirdly, this approach isn't capable of addressing the hundreds of local areas that would need to update their infrastructure to the new system.
On the other hand, as I don't keep a radio in my house, I guess we're all expected to go turn on the radio in our cars if cell service drops? I'm not sure that'll be a response many people think of...
I'm not sure that's an argument against an AM emergency broadcast system, but I'm also not sure if cars are really the place to mandate them. I wonder if there's regulations requiring government organizations (post offices, libraries, and/or police stations) to keep AM receivers on-hand?
It arrived, I plugged it in, and somewhat familiarized myself with how it worked.
And then two days later it was lit up, blaring as a tornado was making kindling of homes about a mile from where I live (West Omaha, Nebraska).
While the cell phone also kicked off, I like the redundancy and non-reliance on cell.
(Apparently the sound of the tornado warning is already imprinted in the mind of one of my cats. While I was watching tornado videos on YouTube, she crawled under the couch when she heard the familiar sound coming from my laptop.)
Glad you made it out of the tornado intact. I'm in Kansas and I really dislike this time of year.
AM radios are about $10 new, and probably considerably less at your local equivalent of Goodwill. Having one seems like a very cheap and very simple disaster preparedness measure.
[1] https://www.amazon.com/Portable-Shortwave-Operated-Reception...
with some effort you can probably find one under a dollar new
That would be the first thing I would do if the power/cell service was out and the emergency sirens were going for a while.
Not too sure I agree with a mandate to require a radio to be installed in every new vehicle as there are a few reasons I can imagine someone would order a car/truck without one. Maybe they intend to immediately replace the factory system with a full on custom block thumper or a company doesn't want their employees to get any funny ideas by listening to NPR or something.
Once you’re on AM, it works just like FM from a user perspective. Just tune to the station you want, or hunt until you hear words or music instead of static.
Wow, which lobbyists convinced a critical mass of legislators to support a mature, resilient, democratic information delivery platform with content funded by non-invasive advertising, for the benefit of a non-subscribing public?
If you want to hear the most unhinged broadcasts possible, that’s where you go.
Sturgeon's law.. is an adage stating "ninety percent of everything is crap". It was coined by Theodore Sturgeon, an American science fiction author and critic, and was inspired by his observation that, while science fiction was often derided for its low quality by critics, most work in other fields was low-quality too, and so science fiction was no different. Sturgeon deemed Sturgeon's law to mean "nothing is always absolutely so".THe internet network and the mobile phone network has many parts. A breakdown in any of these parts would disrupt/break communications A mobile phone cell (depending on technology) is often only a small size or diameter. A mobile phone base station is reliant on the electricity supply. If the wired electricity supply is down ( during an emergency) the mobile phone base state MAY have batteries that will run it for a while. Where for a while would be measured in hours. During emergencies such as flood or fire such base stations maybe out for many days. Broadcast band AM radio signals , normally 500KHz to 1.6MHz can have a reliable transmission range for typical broadcast transmitter normally several KW power ) of RELIABLE 100 miles during the DAY. AM radio range during night can be 1000s KM. The mobile network is prone to failure during emergencies and is hard to make robust. Opposition to AM network usage for emergencies would be from entities that want a small cost reduction in car manufacture.
It provides high quality digital broadcasts on the same spectrum as AM and with way more power efficiency.
Receivers cost nothing and are immune to EV radio noise.
The cover story is that these stations are needed in cases of emergency. If that was actually what was going on congress would allocate funding to distribute portable AM radios to citizens-- radios that can be used when your car is destroyed or inaccessible like it will be in a hurricane, flood, or blizzard. If you even have a car.
The best part is that the poorer you are, the more likely you are to have an AM radio. The only people congress would need to subsidize AM radios for are upper middle class laptop warriors.
https://en.wikipedia.org/wiki/Minot_train_derailment
> The Minot train derailment occurred just west of Minot, North Dakota, United States, on January 18, 2002, when a Canadian Pacific Railway freight train derailed, spreading ammonia gas across the city, delaying rescue operations. The cause was found to be small fatigue cracks in the rails and joint bars, not detectable by the inspection routines then enforced by Canadian Pacific.
[snip]
> Because it was the middle of the night, there were few people at local radio stations, all operated by Clear Channel with mostly automated programming. No formal emergency warnings were issued for several hours while Minot officials located station managers at home. North Dakota's public radio network, Prairie Public Broadcasting, was notified and did broadcast warnings to citizens.
And Minot is one of the bigger cities in North Dakota.
Hitler basically sort of did this and it was wildly successful for them.
Taiwan is tiny. You need only a few FM towers to cover the whole country.
FM's range is low. AM's range is much, much higher:
"However, during nighttime hours the AM signals can travel over hundreds of miles by reflection from the ionosphere, a phenomenon called "skywave" propagation. (Shortwave stations, which operate using AM modulation on several bands between between 2.3 MHz and 26.1 MHz, also use this phenomenon to broadcast still greater distances, up to thousands of miles.) Because of this change in signal propagation from daytime to nighttime, if every AM station kept its daytime operating power at night, massive interference would result. (For a similar description, see Hours of Daytime-Only AM Broadcast Stations, First Report and Order, BC Docket 82-538, 95 FCC 2d 1032 (1983) [ PDF ] and related [ MO&O ])."
https://www.fcc.gov/media/radio/am-stations-at-night
In the US, it's used for all kinds of stations - mostly junk talk shows and sports. And yes, emergencies. When driving on highways, you'll often see signs with lights telling you to tune into a certain AM frequency if the lights are flashing (e.g. landslide ahead).
AM stations in the USA carry a variety of content while being a bit heaveir on "talk" stations over music when compared to FM.
But why the heck mandate thay we can receive it in every car?? I mean, cars are important in America, but why would you need the wordt-case scenario emergency thing in every car! Mandate home radio equipment makers to support it, or mandate one receiver in every house à la smoke detectors. Cheap and easy. But every car? Crazy stupid.
I think this bull is them telling on themselves, since the cost of adding an AM radio would be practically unmeasurable compared with the cost of the car. So where would this bill impact EV range, or efficiency, or affordability? The only way this is possible is if the EV makers have to make their cars emit less electromagnetic noise, I'm guessing.
They're pretty cheap nowadays even for one-off consumer purchases. I imagine the cost would be minimal on an automaker's scale.
I find that hard to believe. I understand that EV motors cause interference, but this seems like a solvable problem - and even if not, it could still work when the vehicle is parked.
It benefits from comparative simplicity and longer range than FM. It can also be trivially connected to digital modes for even longer ranges and reliable data transmission.
Crude receivers can be made from readily available materials and require no local source of power.
Maintaining a national network of AM broadcasting stations by ensuring economic viability is a low cost method of ensuring communications resiliency for the nation under the worst of circumstances. I can’t say for the difficulty of filtering EMI from EVs, but assuming that a vehicle already will have some kind of audio system, AM radio is a <2$ add to an existing radio receiver.
Think of it as a 2$ per car one time tax to ensure improved worst case CCC capability for the nation in the face of the most acute threats to the population.
And often more reliable and better than just relying on a navigation app to route you around bad traffic.
In the Pacific Northwest you will also get updates on border traffic between Washington and BC, and also WA and BC ferry information.
Our family sat in the minivan in the driveway and tuned to KFWB News 980 AM right as their station returned to air on backup generators.
https://en.wikipedia.org/wiki/KFWB
It no longer broadcasts news, but AM station KNX could/would effectively do the same.
Um, what? I'm not an electrical or automotive engineer, but this doesn't sound true. AM radios can be small, light and cheap, and in terms of power, the important components are already in the sound system, right? IDK what would need to be involved to address the issue of interference from the motor, but I also don't think anyone's saying they have to build anything heavy or power-hungry.
man, if that was my name, I would demand my name to always be printed as Al Gore. Imagine the disappointment people would have when I turned up instead of whatever someone might have thought. That's so me to be the epitome of that disappointment
[0] https://www.politico.com/newsletters/the-long-game/2023/01/1...
Now, running Unreal Engine in the dashboard actually does affect vehicle range. Some infotainment systems are real power hogs.
The great thing about AM radio is that it can receive even if all other infrastructure for hundreds of miles around is down. It's not that you get your initial alert over AM radio. It's that you turn it on after the disaster and get some useful info.
For the record: I love Ed Markey. I’m in his congressional district. (Technically, I’m in his town - his registered congressional address is in Malden, MA!) I’m kind of surprised to see him co sponsor with Ted. But I’m pleased that the two of them are working together.
We need more public examples of this - or more publicity for the examples of this that go down. I’m sure there are lots. They’re just not as cinematic as culture war stories.
That is advanced stupid.
Is this a hard problem to overcome?
https://en.wikipedia.org/wiki/Minot_train_derailment
> The Minot train derailment occurred just west of Minot, North Dakota, United States, on January 18, 2002, when a Canadian Pacific Railway freight train derailed, spreading ammonia gas across the city, delaying rescue operations. The cause was found to be small fatigue cracks in the rails and joint bars, not detectable by the inspection routines then enforced by Canadian Pacific.
[snip]
> Because it was the middle of the night, there were few people at local radio stations, all operated by Clear Channel with mostly automated programming. No formal emergency warnings were issued for several hours while Minot officials located station managers at home. North Dakota's public radio network, Prairie Public Broadcasting, was notified and did broadcast warnings to citizens.
And Minot is one of the bigger cities in North Dakota.
Even in 'merica, most people don't quite spend most of their time in the car. And who has an AM radio at home or with them? Like it or not (I don't), but smartphones is the medium to reach the vast majority of people. And if in a disaster cell phone services is interrupted, that will the be first to be restored (before water and power), by temporary means if necessary. E.g. Cisco has an emergency response team with mobile tech.
Only 1%? Surely we can leave 1% of americans behind in an emergency.