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Comment by superkuh | Hacker News Reader

This is an important law to pass. Not because of it's intended effects but because of the unintended. I strongly support it.

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.

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While I agree, this bill doesn't appear to put any pressure on automakers to reduce RFI.

Hey HAMs: You thought the noise floor was bad now, wait a few years when huge RFI vehicles are roaming all over the place.

The better to see you with, my dear, said the sky to the fly.

Actually, they really are better than ICE vehicles. Alternators are horrible.

Really? I always thought it was the coils firing for the spark.

I thought it was the spark itself.

I was under the impression that the FCC has mandated spark ignition standards for the better part of a century. Shielded spark plug cables with a return path for one.

Only ones with spark plugs.

Diesel engines don’t produce such electronic noise — hence why they’re used in radio quiet zones.

I wouldn't get your hopes up. Depending on how the final bill is written, simply equipping the vehicle with an AM radio might be enough to satisfy the regulation, even if the reception is so poor as to make it almost unusable.

Software defined malicious compliance. “Sure, it can tune to AM. Ticket closed.”

Just keep kicking the can until the last ~4k AM stations in the US close.

Aren't there also information and emergency stations run by the state DOTs? I've seen signs to tune to AM stations on roadways.

They also do it on FM in some places, I don’t think it matters a great deal what band it is in.

It matters a great deal. While AM quality sucks, the modulation is more robust than FM and the AM band (specifically as opposed to the modulation) can go much further.

> ... can go much further.

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).

On a regular car radio? I think usually the ones coming from other continents are "shortwave", which is also AM.

I was using a car radio. The secondhand stories were also about people using car radios. YMMV, of course, but it seems possible: https://www.reddit.com/r/radio/comments/hmmy8l/farthest_am_s...

Very cool. I didn't think it would get that far.

Ya, AM. The 1Mhz band is insanely long range (under the right conditions, blah blah).

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

AM band frequencies has greater range under the right ionospheric conditions.

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.

Sure. And you reliably get those range boosting conditions daily.

The point is that anything besides line of sight is unpredictable, so the ability for AM to sometimes reach around the world is irrelevant if you need to know how many people it will reach, which is, more or less the same as FM.

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.

If the automakers don't care about reception quality, then why oppose this law? Bad reception in their cars will make their cars look bad, if only by a little, which is why they care.

I'm here, on this website, reading about the ins and outs of AM reception and considering the effects of mandating the continued existence certain kind of modulation. I also bought a new car recently. In the Venn diagram of people, I'm probably right in all of the tiny overlaps (save for, maybe, concern about current baseball scores).

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.

The overlap of people buying an EV and who listen to AM radio regularly enough to care is going to be minuscule. I’d even hazard that once EVs are mandated.

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.

The car manufacturer lobbying evidences them caring.

Do they care about the brand damage or the need to factor it into their product with hardware/software?

I think the latter is significantly more likely.

If they don't care about reception quality then they don't need to factor anything in; the AM radio would be a trivial addition to the FM radios they already have. But they lobbyied against this because they do care, they'd rather have no AM radio than one that works poorly.

The key word is “addition”. That’s extra hardware, software/buttons regardless of how trivial

It's fuck-all hardware, FM and AM radios have been paired together since the 80s as an absolutely trivial expense; it probably costs them more to get FM hardware without the AM than to get both as a package. In fact their hardware is probably AM capable already, merely unexposed in the user interface. And buttons? Who is still making cars with real buttons for the radio?

It's not about the radio in the car. It's about the required FCC testing, specifically radiated emissions. It's about what spectrums they check new devices at during that testing to be sure they don't interfere. If they stop checking at those frequencies because we stop making AM radios then we have the potential to loose the ability for even pre existing AM radios to work because all kinds of things will be unintentionally broadcasting in those spectrums.

You should be a lawyer.

If the car companies are fighting this in this manner, they must be receiving enough complaints from users with the poor reception issues so that this is the maker's solution.

Operates only when car is booted in special mode where all other electronics are shutdown.. Seems reasonable and smart solution.

Wouldn't that technically lemon law the vehicle - repeated service for the same non-correctable issue?

I guess the workaround would be that it only lets you tune AM while stopped. Ridiculous on the surface, but for receiving emergency information, pulling over first isn't entirely out of the question.

"pulling over first isn't entirely out of the question."

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.

> It is entirely possible to minimize and mitigate these conducted and radiated emissions.

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.

so instead of making the silent electric cars make some sort of noise for pedestrians to hear, they should all just carry a device susceptible to the EMI an EV generates to allow for proximity awareness of a silent EV approaching. /s

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?

Simple: motor inverters are switching power in this frequency range.

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.

> It’s already below FCC limits for unintended radiation

When things are brand new and in good condition, yes, probably.

> Where is it being generated

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.

If RFI interference is the actual problem, this is a terrible bill because it does nothing to limit that. Regulate for the actual problem; unintended consequences will always have other unintended consequences.

The law says they need AM radio -- it doesn't say it needs to be good.

If only there was a way to make radio signal clear even with background noise. Maybe one day someone will invent frequency modulation instead of this stupid AM thing

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