Does your microwave interfere with Bluetooth? Mine does
I can see the Faraday cage in my microwave. It's never cooked anything outside of it. But if I put my phone on one side of it and a Bluetooth speaker on the other, running it interrupts the connection to the speaker. Sound gets through but it's choppy.
Seems bad, right?
You're expecting 1000 watts of RF to be attenuated to less than a few microwatts... as they use the same frequency band.
Try cleaning the mating surfaces around the door thoroughly. If that doesn't work, consider replacing the microwave or relocating the speaker.
Does the sound quality improve if either the phone or speaker are inside the microwave? We must test all possible scenarios.
Yes, sound in my headphones is distorted when I go near a working microwave oven.
My data is anecdotal, but I've observed that Panasonic inverter ovens that I've used interfered in the 2.4GHz range, while models of other brands (e.g. GE) have not.
(This is unfortunate because Panasonic seems to be the only brand that can actually adjust power output, whereas the others simulate lower power levels by cycling on and off.)
Microwaves typically run 2.500GHz, most bluetooth and wifi is from 2.400 to 2.480GHz to keep some space between them (so if you want to minimise WiFi/Microwave issues on 2.4Ghz, use a low WiFi channel).
Bluetooth is adaptive and will hop frequencies to find quiet space in the range above, however microwaves are an intermittent source so when they go on the leakage will kill any bluetooth that's on a nearby frequency.
An easy way to see this is with a BBC microbit; you can measure the signal strength on channels 1 to 100 (2.4 to 2.5GHz in 1MHz steps) and so plot the local RF sources (WiFi, Bluetooth, Microwave, etc.).
What happens when you place your phone in the microwave (don't turn the oven on, obviously) and walk away with your speaker? I'm curious what kind of range you're getting.
For reference: I just tried this with iPhone 13 mini + WH-1000XM3 and the connection dropped after ~5 meters.
They both use 2.4GHz. A tiny bit leaks out of the microwave.
A tiny bit leaking out isn’t bad just like the tiny amount of power used by Bluetooth over 2.4GHz isn’t bad.
Microwaves aren't perfect faraday cages and a little spectrum bleed does happen. Not enough to cook you but definitely enough to make your wifi call or Bluetooth device can get iffy if the microwave is in the path of the sender and receiver.
Depends on both the microwave and the bluetooth device in question. My favorite pair of headphones are rather inexpensive and my microwave is a couple decades old and very high-wattage, and I get interference if I stand within a couple feet of it. I haven't had any other microwave or any other bluetooth device experience noticeable interference.
Around 15 years ago my wireless Magic Mouse's pointer movements would become so choppy as to become unusable not just if my microwave was in use, but also if a neighbor's was.
But upgrading to a new laptop+mouse fixed it, and I've never had a problem since.
Since they're on roughly the same frequency, interference makes sense. Microwave ovens are high-energy, Bluetooth is low-energy, so minor leakage can still have a big effect. But there's no health concerns or anything, precisely because it's still so low-energy. (You can't cook food with Bluetooth!)
But it does seem like some Bluetooth chips/stacks are better at hopping around frequencies to avoid it than others, or that particular devices just develop bugs.
My neighbour's microwave nukes my bluetooth entirely. I have moved to wired everything and life is good finally!
Didn't Wi-Fi originally use 2,4 GHz because it was free to use (without needing a license), because of the noise produced by microwaves on this frequency?
Yep. I've seen Bluetooth be affected by microwaves. Also seen WiFi be affected by Bluetooth.
It doesn't mean your microwave is unsafe.
nope.
Had that happen once, swapped the microwave out and never happened again since.
It did with anything 2.4 GHz (BT, WiFi, Logitech nRF, etc etc). I threw my microwave away. Not really missed it, it was a waste of space, but anyone who wants to do a deauth attack can also get you to disconnect from WiFi.
Right now we got two airfryers, an oven (airfryers are basically mini ovens), and a mini pizza oven. The latter is pretty bad and hard to operate but because our main oven is broken, its as good as it gets. Not much edible comes out of a microwave. The tastes are almost always bland. I'd rather not eat. For my young kids I get to cook plain stuff, they don't enjoy anything complex but like the same stuff like pasta over and over again. We used au bain-marie in past. It requires a little bit more planning but nothing dramatic.
That's inconvenient, but it's definitely expected.
From https://en.wikipedia.org/wiki/ISM_radio_band :
> The ISM radio bands are portions of the radio spectrum reserved internationally for industrial, scientific, and medical (ISM) purposes, excluding applications in telecommunications. Examples of applications for the use of radio frequency (RF) energy in these bands include radio-frequency process heating, microwave ovens, and medical diathermy machines. The powerful emissions of these devices can create electromagnetic interference and disrupt radio communication using the same frequency, so these devices are limited to certain bands of frequencies. In general, communications equipment operating in ISM bands must tolerate any interference generated by ISM applications, and users have no regulatory protection from ISM device operation in these bands.
> Despite the intent of the original allocations, in recent years the fastest-growing use of these bands has been for short-range, low-power wireless communications systems, since these bands are often approved for such devices, which can be used without a government license, as would otherwise be required for transmitters; ISM frequencies are often chosen for this purpose as they already must tolerate interference issues. Cordless phones, Bluetooth devices, near-field communication (NFC) devices, garage door openers, baby monitors, and wireless computer networks (Wi-Fi) may all use the ISM frequencies, although these low-power transmitters are not considered to be ISM devices.
So basically the microwave oven's Faraday cage needs to block enough for safety. There are regulations about the radio spectrum, but they allow it to emit some.
Yes. My work microwave is just at the end of my Bluetooth range for my Airpods Pro.
If the microwave is off, then my signal is basically fine and won't cut out.
Once I turn the microwave on, all are bets off, and it cuts in and out.
I noticed a quirk in my microwave recently if you apply pressure to the door handle it'll turn on the microwave. Kinda spooky.
I had a microwave that interfered with my 2.4 Ghz WiFi signal. If the microwave ran for more than 30 seconds any devices connected to the 2.4 Ghz SSIDs would "stop working". I assume is was due to too much noise caused by the microwave. Devices connected to the 5 Ghz SSIDs worked fine.
Anytime somebody runs the microwave in my office, my headphones start crackling. I'm sitting probably 20 feet from the microwave and my computer (source of the bluetooth signal) is right next to me.
I think microwaves ovens are allowed to emit up to 1W of energy. As mikewarot said - it's amazing Wifi/BT works at all.
Is the interference from leaking microwaves themselves or resonant leakage from the magnetron and/or support circuitry which is desired to be as cheap as possible?
Also you can’t really see the cage: that mesh you see in the window is indeed designed to block emission, but in a cheap one you can often see a gap between the mesh and the bezel, and of course the shell is a cheaply assembled rectangle without tight corner fittings so is probably leaking a small amount here, especially at the back, where they assume a wall will catch any leaks.
My microwave is less than 2 feet from my wifi router :D (but yeah, mostly use 5GHz channels for wifi)
I have no issue listening to podcasts in the kitchen while the microwave is running. I'm using Logitech H800 headphones (modified with wires going to my hearing aids).
If I put my phone in my GE microwave, I have sound breakup issues within 2-3 feet away from the microwave. Sounds like it's better "shielded" than some others mentioned here.
At an old apartment my Chromecast would become unusable whenever I'd use the microwave in the other room. It took me a bit to understand why every now and then it would just take a dump, turns out it was my roommate cooking dinner.
Meanwhile my current microwave I can cook and be on bluetooth headphones paired to my laptop across the house and there's no issue.
Some microwaves are better shielded than others. It might be leakage from the actual cook box, it might be leakage from all the extra circuitry.
Even though the frequency of most microwave's primary element is going to be a little higher than what Bluetooth is supposed to run on, if there's enough energy leaking you'll still potentially drown out the signal. Filters, especially ones made to be kind of cheap, aren't perfect and can't always filter out everything.
And as mentioned you're trying to catch a few milliwatt signal right next to something that's trying to generate and contain a 1,000,000 milliwatt signal.
I used an SDR to check my microwave's emissions. They were pretty narrow and stable-ish. Not stable like an actual radio, but not all over the place wrecking all of the wifi channels.
I've not had it interfere with bluetooth or wifi. Bluetooth frequency hops, and moves away from channels with interference (dropped frames), doesn't it?
I have a couple of illustrations at https://blog.habets.se/2017/06/Microwave.html
Yes. I've wondered about this for a while. Because although the microwave is supposed to be fully shielded, when I take EMF readings on it with my TriField TF2 EMF meter, it's spitting out >100mW/m^2 when it's turned on. And I've seen this happen with just about every microwave I've tried this on. The only ones that haven't seem to be those expensive integrated under-counter ones where the tray slides out rather than opens like a door. Also my phone still works/receives calls when I put it in there, so it can't be as good of a faraday cage as it's supposed to be...
My first microwave absolutely wrecked 2.4 ghz wifi, replaced it after a few years and the new one didn’t. Didn’t have many BT devices back then, but bet it would jam them as well.
My Bluetooth headphones usually experience connectivity issues if I have line of sight with my running microwave. Interestingly it only happens sometimes. Usually audio will stop playing or cut off until there's a wall between me and the microwave.
I have the same interference with the microwaves at work.
There's also a small plaza in what's considered the very center of my city where I get tons of interference (sound basically keeps cutting as if I was losing connection). There's a subway station underground, and some trolley cables suspended in the air, so maybe there's some sort of power converter underground.
It destroys the wifi of whatever phone or tablet is next to it while running.
I used to have to time my gaming around when roommates would be eating. Anything in the microwave was an instant dead connection
My neighbors have something crazy emanating from their house. None of my Bluetooth devices, from Bose to Plantronic to new AirPods Pro, survive signal connectivity when I walk past their house. The connection gets very disrupted and the devices have trouble reconnecting.
So I have to leave everything off when I go for a run and not connect headphones until I make it to the end of the street. It’s weird.
My bluetooth often dies when I'm near tram tracks and their overhead electric lines in my city. Kind of annoying given that there are tram tracks everywhere.
You can demonstrate WiFi interference by putting a laptop next to your microwave and running a ping test to your WiFi router. I can put my laptop about 4 feet from my microwave and the ping test hangs as soon as the microwave starts. The ping test resumes as soon as the microwave stops.
I once had a microwave I called "The WiFi Killer". I work from home, and did then too, and every time one of my kids, or my wife, would use the microwave, I'd get knocked offline. They do work at 2.4Ghz, and this microwave was pretty old. Replaced it and never had another problem.
No, but my reclining chair's motor interferes with the digital signal my TV recieves.
In the early days of Wifi, it was pretty common to have your connection drop out whenever someone used the microwave. Both systems use the same frequency band.
I assume modern Wifi has gotten better at chugging through the interference (and perhaps microwave-makers better at shielding).
> Ask HN: Does your microwave interfere with Bluetooth? Mine does
As far as i know you can make a complain by the FCC.
Bluetooth and WiFi both borrow their spectrum from microwave ovens. It's typical and expected that microwave ovens will cause some interference with other users of the 2.4GHz ISM band that are very nearby. Microwaves operate at very high power levels and are required to be shielded for human safety, but the permissible leakage power is relatively high compared to typical WiFi and Bluetooth devices---there's a simple reason why. From a legal perspective, Bluetooth is essentially pretending to be a microwave oven and making use of the permitted leakage power.
This is the cost of the historical regulatory situation that most of these unlicensed radio services use the ISM bands originally allocated for microwave heating. One of the advantages of newer WiFI standards, particularly WiFi 6E, is that they finally change this situation by using the U-NII bands allocated specifically for unlicensed short-range digital communications, rather than for microwave heating.
Mind that this is all in the context of US spectrum regulations, although other countries have largely harmonized their approach. I have a lengthier treatment of the topic here: https://computer.rip/2022-04-14-unlicensed-radio.html
My bluetooth headphones occasionally drop the connection for a moment when I'm standing to my microwave which is warming up food. 2.4GHz after all. Bluetooth and USB 3 don't play along that well either btw.
There's a particular spot on a local highway that interrupts my wireless CarPlay connection if I spend too long in it (eg when traffic is slow). It's right next to an exit with a bunch of buildings (including a hospital) so I'm sure there is some massive emitter in one of those buildings. I'm still at a loss about what could cause that kind of interference inside a major city and still be legal.
Nope - zero interuptions. Using some cheap ikea microwave.
Tangentially related: knowing they use the same frequency band, I actually used the work microwave oven as a faraday cage for testing our product which used bluetooth. (Close microwave, observe signal drop behavior). I was bemused to note that you could still connect to a device inside the oven, over short distances... Hopefully the attenuation was sufficient for safety when using it to cook!
[ For clarity - the oven wasn't on when I used it as a faraday cage]
Nope, this is completely normal.
Many commenters are saying microwaves are pretty narrowband.
Maybe some are, but I've done spectrum analysis on a few college-dorm-level microwaves in our office with a Wi-Spy and all 3 of these microwaves spam all of the 3 usable 2.4ghz wi-fi channels when cooking.
We see similar fun in iMac labs, when they're all (attempting to) use Bluetooth Apple Magic Keyboards at once.
In a related question, does anyone know why my Bluetooth earbuds frequently experience brief disruptions when crossing the street at intersections? It happens far too reliably to be a coincidence.
microwaves emit RF, heavy concept right?
I once worked for a startup that was trying to stream ads over bluetooth using microwavable foods. It _worked_, but ultimately used too much bandwidth to be practical at the resolutions advertisers wanted.
Yes, my flatmate had a very old 20+ yrs old microwave (the type with a mechanical dial) and when he used it my WiFi would completely drop out until the cooking was done.
I bought him a new microwave because I was sick of dropping zoom calls. The modern LG microwave was much better and has virtually no effect on the WiFi.
An interesting construction detail of the cheap modern microwave is that it only operates on one half of the mains electric waveform: microwaves use a single high-voltage diode which acts both as half-wave rectifier and voltage doubler. Thus the magnetron only operates with a 50% duty cycle.
In theory 2.4 GHz communication protocols can easily time their transmissions to fit in the gaps left by the microwave. 50% bandwidth loss but no other effect.
This obviously isn't foolproof in practice, when 2.4 GHz was a thing I remember my WiFi dropping off whenever somebody was nuking some food. But perhaps this might have been a quirk of my Panasonic inverter microwave - which obviously is not the simple standard circuit.
The 2.4GHz spectrum is shared between Bluetooth and WiFi 802.11b/g. A few years ago, I was doing some work using an Ubertooth-One scanner (https://greatscottgadgets.com/ubertoothone/). It was showing the traffic on different channels.
My wife stuck a burrito to warm up in the microwave a room away (30-40 ft). This was with a brand-name model, so presumably properly shielded, etc.
Nope. The entire spectrum just went white with noise on all channels.
Once the microwave cycle ended, it still took a good 15-30 seconds before the airwaves calmed down and went back to normal traffic.
The microwave became a second class citizen in our kitchen when we got the toaster oven/air fryer combo unit and then was relegated to the garage on top of the fridge. We still use it for popcorn and the occasional hot cocoa and if my coffee gets cold on the weekend I'll wander out there to warm it up. It is almost unneeded.
WiFi is better as a result.
My microwave oven definitely interferes with anything Bluetooth, like headsets etc. Although audio still somewhat works from a laptop upstairs ~30-50 ft away.
Anyways, this is normal. Microwave oven generates a lot of 2400-2500 MHz ISM band noise. You're fine.
I have a waterpik whose motor absolutely obliterates 2.4ghz. I sometimes use it while wearing bluetooth headphones, and music immediately stops. It took me awhile to figure it out (I thought it was my head leaning down and putting a metal pegboard between me and my work machine, but nope).
London Underground announcements in certain stations seem to break Bluetooth really frequently. I suspect that at some point, the message is being transmitted by radio and this must be at a frequency that interferes.
Also seen on platform WiFi messed up in a similar fashion - this causes the most grief when calling over WiFi kicks in, you make a call only to find it get wrecked the moment they start announcing. Luckily in some stations you actually get a better signal over mobile, so simply turning off WiFi resolves the problem.
My waterpik kills bluetooth to my airpods.
Somewhat related, my bluetooth headphones get some static noise when I use my induction oven. On max power ~1900w it disrupts my headphones in a ~2m range haha
There is this very popular night market where I live, and whenever I drive through a corner of this market, the Bluetooth in my car just stops. I always wondered what this was. There is just so much interference on a square meter.
Related question:
I used to be able to use wifi when my microwave was running. Then one day with no apparent change it started interfering, so that I can no longer use wifi if the microwave is roughly between the two devices connecting over wifi.
Of other microwaves I’ve encountered, most haven’t interfered with wifi, but one or two have.
Is this a problem?
Everyone, who see possible interference from microwave, should ask nearest service and make checks, as this could be manufacturer defect or just leakage of old insulation (rust under paint), and it could be dangerous for health.
PS and yes, my friend once found rust hole in old microwave, so this is not very rare thing.
Yes, we had an LG microwave, took it back after 3 weeks because it knocked out both wifi and Bluetooth. The store didn't want to refund. Said it had to go to warranty repair. Repair shop said they cannot decrease RF emissions, store begrudgingly gave credit.