[kylehotchkiss]

I just saw somebody mention (on an amazon review for an Aukey charger) that their USB-C car charger was interfering with TPMS system on their car. That's a little scary. Hopefully they'll get it ironed out soon.

I realize TPMS is not 2.4gz but thought that was relevant to interference concerns

[vvanders]

There's actually a ton of RF interference out there, just that it doesn't impact enough people on a regular basis for anyone to do anything about it.

The 2 meter radio I have in my car goes crazy with RF(up to S9) when I drive through the local Starbucks. That said bringing it up with anyone will probably get you a couple funny looks and not much else.

(things are even worse on HF and the like)

[blattimwind]

A number of ham radio bands became unusuable due to interference over the years.

[LeoPanthera]

Notably, powerline ethernet destroys nearly the entire HF range, from 3 to 30MHz. This isn't just bad for radio hams, it ruins shortwave and some AM radio too.

[vvanders]

The hell? (just checked youtube and you're right.)

How did that ever make it past FCC certification? I understand unintentional QRM from cheap things but that is something that's spec'd out.

[nikanj]

HAM operators don't have money. Networking equipment makers do have money.

[vvanders]

Oh they do, we just spend it all on our radios ;).

[jstanley]

FWIW, I use powerline Ethernet and I can pick up HF just fine.

[kakarot]

The issue is that as you and others use powerline ethernet, you leak electromagnetic interference patterns back into the powerlines. This buildup of interference from multiple homes creates problems around your area, even if you don't notice it yourself.

[Dylan16807]

So if users had a small low-pass filter installed at their fuse box it wouldn't be a problem?

[semi-extrinsic]

Maybe stop driving your car through coffee shops? Sounds expensive and cumbersome even without the RF interference.

[squarefoot]

Radio interference from switching voltage regulators, power supplies etc. is normal as most of them work from several hundred KHz to above 1 MHz generating PWM square waves whose harmonics fill the spectrum up to hundreds of MHz and beyond. They're circuit-wise very close to RF transmitters, so it's a normal behaviour. The RF junk they produce however can be filtered out both by putting them behind good screening and by filtering both their input and output lines. This cost money though so cheap ones will perform much worse, and some of them don't employ any method at all to reduce interference.

[kurthr]

My favorite source of noise was a Korean fluorescent lamp with power factor correction (makes the inductive lamp load look resistive to prevent parasitic current flow in the power lines). It was square wave chopping the 120-240VAC=175-350Vpp input to the ballast at the plug with a variable frequency (100kHz-1MHZ) based on input voltage phase. A very simple circuit that efficiently coupled >1Wrms into a narrow band (~10kHz fundamental)swept square-wave into a 2m antenna.

I integrated the total power with a spectrum analyzer... but any radio I tested (including GPS, FM, WiFi & GSM maybe due to IF or saturation?) would stop working within 10ft=3m of the lamp. Driving around I could tell if the lamp was on using my AM radio (set to any station) due to the 120Hz buzz from several blocks away.

As far as I could tell it had passed Korean FCC equivalent, several tens of thousands were imported, and sold (at Frys at one point) around the country.

I destroyed ours, but sometimes, just driving around, I think I can hear one when I switch to AM.

[retSava]

Did you report it to the FCC? I understand if you didn't, as a consumer, and this is not an attack on you. But this kind of thing should be punished, and one of the main ways to do this is to bring this to the attention of the regulating authorities.

We can only keep the spectrum in good shape by, as a producer or designer, test and design to comply. As an importer, require and check certifications on what we import. As a consumer, report when we find something being funky. (again, not blaming you)

[TeMPOraL]

Change "buzz" to "scream" or "whisper", and this would be a great horror story...

[mark-r]

Any device operating at those frequencies should have an FCC sticker, meaning they've been tested to make sure radiated RF is below some legal limits. If the cheap devices don't have the sticker or have a fake sticker or were materially changed after passing the tests, they're illegal in the US.

[switch007]

What's scary about TPMS not functioning correctly? Honest question; I've only had a TPMS incorrectly tell me there's an issue so I disable it.

[chiph]

On some vehicles (Honda, IIRC) if the TPMS isn't working (dead sensor battery, interference, etc) the stability control system will assume the tire on that wheel can't be trusted to apply grip when correcting the vehicle's trajectory, so you might not stay on the road in an oversteer/understeer situation.

[izacus]

Did you ever have a severe issue with a tyre that TPMS missed?

[logfromblammo]

I consider overly frequent false positives to be a severe issue, so yes, I have.

[toomanybeersies]

There is always the redundant backup of actually looking at your tyres to see how flat they are.

[dhimes]

Ha! you must be drinking..... ah, the username...