SoylentNews is people
SoylentNews
Congress wants to force AM into every new car for emergency alerts.
The fight over the future of AM radio got a little more heated this week as organizations representing the auto and technology industries told Congress that its plan to mandate this mode of radio wave reception is poorly conceived and will hinder progress.
AM radio has seen almost every other in-car entertainment option come and go—vinyl, 8-tracks, cassettes, CDs—and it might predate just about everything other than playing "I Spy," but time is catching up with this old broadcast technology. It is starting to get left behind as new models—many of which are electric vehicles—drive off into the sunset, streaming their audio instead of modulating its amplitude.
[...] "As more and more Americans adopt electric vehicles, we must ensure that they are equipped with AM radio. AM radio is—and will remain—an essential communications channel for emergency alerts and for disseminating news and other important information to residents of our district and communities across our country. I am proud to co-lead this bipartisan legislation which would ensure that EVs continue to be equipped with this basic but critical capability," said Rep. Bob Menendez (D-N.J.), another co-sponsor.
(Score: 3, Interesting) by Beryllium Sphere (r) on Wednesday May 24 2023, @01:52PM (1 child)
Curious -- could it be worse than spark plugs firing nearby? Car AM radios were stuffed with noise filtering when I first read about them.
(Score: 3, Informative) by RS3 on Thursday May 25 2023, @05:10PM
I'm an ee but not total expert. AFAIK, you can't really filter out spark plug noise coming in to the antenna. Tuned RF and IF sections of a receiver should filter out much of the undesired RF noise, but where the noise frequencies hit your desired carrier, you can't really filter it much.
RFI can kind of "ride" on wires, and "leak" into things like sensitive receivers. "Feed-through" capacitive connections which do a pretty good job of blocking RF in and out of a chassis, but they're for high-end super sensitive receivers, lab equipment, etc.
You can certainly filter the +12V power, and there have been simple filters available (LC) for that purpose. Car radios often had them built in (pretty big "choke" (inductor (L)) and capacitors. They still have filtering, but for very long EE explanations the filtering isn't as much of an issue (I'll explain if you really wanna know...)
The main fix was resistor spark plugs and plug wires. The resistors damp out much of the higher frequency (RF) energy. Of course you lose some electrical spark energy, so racers and hot rodders often use non-resistor plugs and wires to get a "hotter" spark.
Metal car bodies do a lot of shielding. I've seen ground straps going from the hood (bonnet) to chassis to ensure good hood grounding (earthing).
Corvettes often had fully shielded ignition systems because the fiberglass body doesn't block the RFI.
HAM radio people often use copper braid shielding over ignition wires.
All that said, AFAIK all newer spark ignition engines use COP- Coil On Plug ignition, where there is no distributor nor wires. There is one coil (high voltage spark transformer) per spark plug. The wire from the coil to the plug terminal is very short, and almost always down into the engine (through the valve cover) and is pretty well shielded. Plastic valve covers of course don't shield, but there's usually a metal tube into which the spark plug and coil to plug connection are inserted.
Here's a company selling an aftermarket "hotter" ignition with better RFI shielding (random search- I have no connection): https://www.promracing.com/coil-on-plug [promracing.com]
Purely speculating here, but AFAIK, spark ignition RFI is pretty well solved, but electric motor RFI is not yet, and companies don't want to spend the money to correct it. It's not just AM radio, but HAM, CB, and potentially many other forms of radio communications will be affected. The problem is solvable, and IMHO FCC needs to do their job and force the RFI reduction.
(notice I didn't get into the realm of people who are afraid of cell phones, microwave ovens, power lines, etc., due to electromagnetic radiation? Wait until they hear about EV "radiation"!!)