Effect of Microwave Ovens on Wireless Internet
April 16th, 2009
photo: Joshua Davis (jdavis.info)
I noticed something quite odd lately – when the microwave oven in my house was being used, I would lose all connectivity on my wireless internet connection. That lead to the internet dropping out in the whole house – internet radio, game consoles, laptops, etc.
It turns out that the issue is that microwave ovens and wireless internet operate on the same frequencies. My microwave uses a frequency of 2450MHz (check the back of your microwave as yours may be different) and my wireless (802.11g) operated on channel 11 (around 2462MHz). As you can imagine, the microwave oven outputs with a lot more power than the wireless router so totally overwhelms your ability to use wi-fi.
The solution is to change the frequency that your wireless internet operates on.
Firstly, check the back of your microwave oven and find out what frequency it operates on.
Now you’ll want to change the frequency that your wireless internet operates on. As a rule of thumb, you’ll probably want it to be at least 20MHz different from your microwave. As my wireless was operating at 2462MHz, it was well within the frequency range which was susceptible to interference from the microwave.
photo: Un ragazzo chiamato Bi
Here are the wi-fi channels and corresponding frequencies:
| Channel | Frequency (MHz) |
|---|---|
| 1 | 2412 |
| 2 | 2417 |
| 3 | 2422 |
| 4 | 2427 |
| 5 | 2432 |
| 6 | 2437 |
| 7 | 2442 |
| 8 | 2447 |
| 9 | 2452 |
| 10 | 2457 |
| 11 | 2462 |
| 12 | 2467 |
| 13 | 2472 |
| 14 | 2484 |
It’s important to note that these are center frequencies. In other words, your wireless internet will use a range of frequencies around that frequency (e.g. channel 11 is centred on 2462MHz but actually uses all frequencies between 2451MHz and 2473MHz). Hence you need to make sure there is a sufficient gap between the frequency of your wireless internet and the frequency of the microwave. Consult this graph on Wikipedia for more information.
Check local laws too about what frequencies and power levels you are allowed to use. You can use channels 1-13 in most of the world with the exception of channels 12 and 13 in North America.
| About Ken | |
 | My mission is to demystify the world of mobile technology for general audiences and to communicate how mobile technology can enhance every aspect of our daily lives. I've been maintaining the Ken's Tech Tips website since 2004. I have experience communicating mobile technology and presenting new mobile products both online and offline, including at various trade shows and events. You can check out my profile or drop me an e-mail. |
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- Comments(12)
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Dude, this is the clearest, most simply written description of the issues of wifi vs microwave ovens I could find. Bookmarked!
Many many thanks for sharing this
cud this be similar to me losing my kitchen digital tv when i use the microwave ?
What frequency do DECT cordless phones use in the UK? as whenever my wireless router is on and i get a phone call its abit fuzzy.
My wireless router and cordless telephone(with its base) are in separate rooms, so it must be some sort of interference
Also, can a DAB/FM radio cause problems?
Thank you! I know next to nothing about computers (or microwaves for that matter). Following your advice, I changed the channel on my router and was able to use the microwave without losing my connectivity. Your advice has saved my sanity.
Thank you so much Ken for helping me understand why the wi-fi connection disconnects each time my husband runs our microwave oven. We will keep you posted after we change the channel on our router.
Hi Ken,
As other have said, you saved me too, well written.
Thanks !!
Much appreciated. Excellent article and explanation of this common household problem. Cheers mate.
I would strongly advise nobody to mess around with microwave frequencies.
You should not tamper with your microwave oven but there are no risks in changing the frequency channel used by your wireless router.
The problem now is, my router only has channels 1-11. Even the highest channel won't allow for a sufficient gap to overwhelm the 2450 signal from my mircowave…….
Perhaps if your microwave is leaking that much EM radiation, there might be a problem.