6 ms·

TFA mentions AM causing interference in EVs. More accurately, it's hard to isolate an AM antenna from a transformer system. AM reception in EVs is a feat of eng

TFA mentions AM causing interference in EVs. More accurately, it's hard to isolate an AM antenna from a transformer system. AM reception in EVs is a feat of engineering. FM and others still require care but are comparatively easier. 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.

gnicholas 2y ago
Would it suffice to require either AM or satellite radio? We never buy satellite radio subscriptions, but our decade old car has an antenna, and I assume many newer cars do as well. As long as people know how to use them to tune into emergency channels (I don’t!), it might suffice for EVs.
- thsksbd 2y ago
  Satellites are nowhere near as reliable as AM. Tree cover will block your satellite signal
  - criddell 2y ago
    But if the radio is in a car, it can be moved. I wonder if the car manufacturers could get around this by offering free handheld AM radios? In bulk, they probably cost less than $10.
    - thsksbd 2y ago
      And then there are clouds.
gugagore 2y ago
Maybe someone can explain why the modulation scheme matters, instead of the frequency range. AM less sensitive to phase noise? Or is it that AM radio typically means some frequency range?
- 9659 2y ago
  modulation does not matter for range. however FM requires a greater signal strength to convey the information. if you are trying for distance, AM works with less recovered signal. exclusive of digital modes, the most distance effective signal is CW. unmodulated signal, on or off.
  - akira2501 2y ago
    FM uses 10 times the bandwidth and conveys more audio frequency range within it's signal than an AM one. FM has the benefit that building antenna gain is relatively easy so the Total Power Output of FM transmitters is often lower than for AM transmitters. You can generally expect to get 100kW Effective Radiated Power with only 20kW of input. 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.
- toast0 2y ago
  AM and FM radio at least in the US refer to both the modulation and the frequency bands. 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)
  - pcl 2y ago
    > especially if it's an EV; I'm not taking that into the mountains, probably Why not?
    - mauvehaus 2y ago
      Because being in a remote and sparsely served area is exactly the kind of place where it's vastly easier to ride your thumb to the nearest gas station and get a couple gallons of gas in an emergency than to arrange charging or a tow? 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.
ummonk 2y ago
It’s not AM causing interference in EVs. It’s EVs causing interference in their AM radios.
- sigmoid10 2y ago
  Only if you buy a car to listen to radio rather than driving.
  - Spivak 2y ago
    The interference is still coming from the car regardless of which function you think is more important. AM radio waves aren't messing with the car, it's the other way around.
  - krisoft 2y ago
    No. “AM causing interference in EVs” would be that you turn on an AM transmitter and the EV motor starts to shutter or loses power. But that is not what we are talking about. It is that you turn the EVs motor on and the AM reception becomes noisy, isn’t it? It is not about who has been around sooner, or who is more important, but what degrades in the presence of what.
    - sigmoid10 2y ago
      Wrong. If you really want to get pedantic, EM forces affect everything the same way (in line with Newton's third law). So you can have an argument for both sides. But preferring one will always be wrong. Especially if you disregard outcomes that can be felt by humans as you did.
- phkahler 2y ago
  We've been batting that since forever. Having a 3 phase inverter switching 500 Volts at a few kHz does tend to radiate a bit. But it can be controlled and has been so far.
- beerandt 2y ago
  And deleting the AM radio wouldn't delete the interference, just make you more ignorant of/ oblivious to it.
hilbert42 2y ago
"AM reception in EVs is a feat of engineering." 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.
SkyPuncher 2y ago
I just have trouble believing that this isn’t a solvable problem. Surely, the type of interference is relatively predictable.
- BeetleB 2y ago
  Electromagnetic Compatibility is always a hard problem.

gnicholas 2y ago

Would it suffice to require either AM or satellite radio? We never buy satellite radio subscriptions, but our decade old car has an antenna, and I assume many newer cars do as well. As long as people know how to use them to tune into emergency channels (I don’t!), it might suffice for EVs.

thsksbd 2y ago
Satellites are nowhere near as reliable as AM. Tree cover will block your satellite signal
- criddell 2y ago
  But if the radio is in a car, it can be moved. I wonder if the car manufacturers could get around this by offering free handheld AM radios? In bulk, they probably cost less than $10.
  - thsksbd 2y ago
    And then there are clouds.

gugagore 2y ago

Maybe someone can explain why the modulation scheme matters, instead of the frequency range. AM less sensitive to phase noise? Or is it that AM radio typically means some frequency range?

9659 2y ago
modulation does not matter for range. however FM requires a greater signal strength to convey the information. if you are trying for distance, AM works with less recovered signal. exclusive of digital modes, the most distance effective signal is CW. unmodulated signal, on or off.
- akira2501 2y ago
  FM uses 10 times the bandwidth and conveys more audio frequency range within it's signal than an AM one. FM has the benefit that building antenna gain is relatively easy so the Total Power Output of FM transmitters is often lower than for AM transmitters. You can generally expect to get 100kW Effective Radiated Power with only 20kW of input. 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.
toast0 2y ago
AM and FM radio at least in the US refer to both the modulation and the frequency bands. 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)
- pcl 2y ago
  > especially if it's an EV; I'm not taking that into the mountains, probably Why not?
  - mauvehaus 2y ago
    Because being in a remote and sparsely served area is exactly the kind of place where it's vastly easier to ride your thumb to the nearest gas station and get a couple gallons of gas in an emergency than to arrange charging or a tow? 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.

ummonk 2y ago

It’s not AM causing interference in EVs. It’s EVs causing interference in their AM radios.

sigmoid10 2y ago
Only if you buy a car to listen to radio rather than driving.
- Spivak 2y ago
  The interference is still coming from the car regardless of which function you think is more important. AM radio waves aren't messing with the car, it's the other way around.
- krisoft 2y ago
  No. “AM causing interference in EVs” would be that you turn on an AM transmitter and the EV motor starts to shutter or loses power. But that is not what we are talking about. It is that you turn the EVs motor on and the AM reception becomes noisy, isn’t it? It is not about who has been around sooner, or who is more important, but what degrades in the presence of what.
  - sigmoid10 2y ago
    Wrong. If you really want to get pedantic, EM forces affect everything the same way (in line with Newton's third law). So you can have an argument for both sides. But preferring one will always be wrong. Especially if you disregard outcomes that can be felt by humans as you did.
phkahler 2y ago
We've been batting that since forever. Having a 3 phase inverter switching 500 Volts at a few kHz does tend to radiate a bit. But it can be controlled and has been so far.
beerandt 2y ago
And deleting the AM radio wouldn't delete the interference, just make you more ignorant of/ oblivious to it.

hilbert42 2y ago

"AM reception in EVs is a feat of engineering." 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.

SkyPuncher 2y ago

I just have trouble believing that this isn’t a solvable problem. Surely, the type of interference is relatively predictable.

BeetleB 2y ago
Electromagnetic Compatibility is always a hard problem.