Ask HN: Does your microwave interfere with Bluetooth? Mine does

I would contest Wikipedia's description here a bit because I think it confuses the issue of microwave emissions. A number of ISM bands were allocated for RF heating applications originally, 6.78MHz, 13.560MHz, 27.12MHz, 40.68MHz, 915MHz (commonly referred to as 900MHz), 2.45GHz (commonly referred to as 2.4GHz), 61.25GHz, 122.5GHz. These are just examples taken from my NTIA chart which doesn't call all of them out.

The lower ones are largely historic, the very first RF heating experiments used HF and VHF low band which were easier to produce with the radio transmitter technology of the time, but not very efficient at all. The invention of the magnetron changed that, suddenly it was much easier to produce microwave radiation at high power levels, and so the inefficient HF/VHF RF heating devices have all but faded away (there are some specific technical applications that remain exceptions, as usual).

The low frequencies are inefficient and difficult to produce with compact electronics, the high frequencies aren't very attractive for food heating applications because of the limited skin depth. So every microwave oven you're likely to run into operates at 2.4GHz, which is pretty much the sweet spot for food heating among the allocated ISM bands. That band is defined as 2.4GHz through 2.5GHz. So I quibble with describing microwaves as "broad spectrum." Magnetrons do not produce very narrow output, one of the reasons they aren't often used for radio transmitters today, but microwave ovens are required to constrain their meaningful output to within 50MHz of 2.45GHz. 100MHz is a lot of bandwidth from a modern radio communications perspective, but isn't really that wide from a perspective of physical effects.

2.45GHz was chosen as an ISM band in part because it had good properties for heating, but it wasn't put exactly on a resonance frequency for water or anything like that. The exact details of the selection process are obscure but 2.45GHz was already being used for experimental microwave heating before the ISM band was allocated, and I would imagine came out of some combination of ease of magnetron construction and reasonably good heating properties. It is documented, for example, that the EHF bands were never popular for consumer microwave heating because of poor efficacy with food, although they do have industrial applications (especially in welding).

Given the history of the topic there's a decent chance that 2.45GHz came about because it was being used by experimental radar at the time, the main thing that magnetrons were being built for. Microwave heating was basically a byproduct of radar development during its early days of development.

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 had a colleague who "discovered" a pulsar that later turned out to be a radar at San Francisco International Airport. I occasionally still text them photos of the "pulsar" when I have a layover at SFO.

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.

I've read that the way to determine if your microwave is properly sealed is to put a phone inside of it, close the door, and then try calling it. I've been unable to get the phone to ring last time I did this ~12 years ago, though if there's some expected leakage, I suppose proximity to the cell tower is a factor