7 ms·
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 litt
by kylehotchkiss 9y ago
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 9y agoThere'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)
- semi-extrinsic 9y agoMaybe stop driving your car through coffee shops? Sounds expensive and cumbersome even without the RF interference.
- blattimwind 9y agoA number of ham radio bands became unusuable due to interference over the years.
- LeoPanthera 9y agoNotably, 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 9y agoThe 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.
- jstanley 9y agoFWIW, I use powerline Ethernet and I can pick up HF just fine.
- kakarot 9y agoThe 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 9y agoSo if users had a small low-pass filter installed at their fuse box it wouldn't be a problem?
- revelation 9y agoA low pass filter that can pass 50 kW isn't exactly a trivial device or small in any sense of the word.
- Dylan16807 9y agoLow pass filters don't have the power go through them. It's a capacitor going across the power supply, with a resistor for damping.
- vvanders 9y agoExcept unless you have some sort of an impedance follower you'll probably just end up attenuating your powerline networking to the point of not working.
- Dylan16807 9y agoMost of the useful signal in the system is going directly from one circuit to another. The signal headed out toward the power meter is mostly dead, and you might even improve the networking by getting rid of those extra echoes. Unless I'm mistaken?
- squarefoot 9y agoRadio 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.
- mark-r 9y agoAny 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.
- kurthr 9y agoMy 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.
- TeMPOraL 9y agoChange "buzz" to "scream" or "whisper", and this would be a great horror story...
- switch007 9y agoWhat'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.
- izacus 9y agoDid you ever have a severe issue with a tyre that TPMS missed?
- logfromblammo 9y agoI consider overly frequent false positives to be a severe issue, so yes, I have.
- chiph 9y agoOn 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.
- toomanybeersies 9y agoThere is always the redundant backup of actually looking at your tyres to see how flat they are.
- dhimes 9y agoHa! you must be drinking..... ah, the username...