The humble microwave oven. Its a kitchen appliance that we have all taken for granted for many years, however,  are you aware of what exactly it is doing to you, the surrounding environment and also the food?

The EMF Safety Test

The first test I did was with an EMF meter. It’s a cheap one from the evil online shopping store, named after a rainforest. It does the job. I tested it against some electrical equipment – my desktop computer, speakers, fan, etc and that worked as expected, showing less than 1 microTesla.

Next thing I do, is walk up to my microwave, and the device suddenly glows red and squeals like a pig. Going from a background EMF measurement of 0.00 up to 64.3 μT. I was pretty amazed.

Microwaves are prone to leaking EMF energy and need to be repaired or replaced if they leak too much. So, armed  with this reading I looked up what is deemed a safe level to be exposed to. It seems that everyone works in mGauss. I’m a big fan of Tesla’s works, and as such will stubbornly stick to the unit of measurement.

Thankfully, the maths were quite simple, even I could do it – 1 Gauss is equal to 0.0001 Tesla, or 1 Tesla = 10,000 Gauss, so 64.3*10 (going from μT to mG, so shedding a bunch of zeros) = 643 milliGauss.

A lot of reading up later shows that this is okay as long as I dont keep any part of my body against the side of the microwave for extended periods of time. Seems legit.

The Wifi Test

A drunken purchase a couple of years back yielded me a lovely little device called a WiSpy which lets me visualise the 2.4ghz and 5ghz Wifi spectrums.

So I set my little test laptop up with it on (Its an old I5 EliteBook), and took a baseline scan of the 2.4ghz frequency range.

As you can see, my wifi channel is quite obvious  on the top two views. Next, I emptied a can of rice pudding into a bowl and stuck it in for a couple of minutes. An unhealthy evening meal in the name of science. Once the microwave was running, I monitored.

Immediately everything just went mental. As you can see the noise suddenly has appeared all over the channels, and my somewhat clean channel on the spectral view has disappeared.

Once it had finsihed cooking, and the bowl of hot milky rice stops going around in circles, it’s pretty obvious that if I had anything on Wifi channel 9, it’d be as good as useless.

Next Steps

So this was quite interesting to see what effect the microwave had on the 2.4ghz spectrum. I’m hoping to hunt out my SDR and have a look at some other ranges to see if there’s anything else going on. I may even extend it out to other equipment – see how much noise devices have to radio frequencies.

EDIT: I found my SDR, but it only goes up to 1.7999ghz, nowhere near the 2.4ghz I need 🙁

Categories: Tech

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