Interference Issues: Wi-Fi vs. Microwave Ovens

Reader Bob writes: Every time I use my microwave my wireless connection is interrupted. Why does this happen? Is it dangerous?

Microwave ovens and Wi-Fi hardware both emit signals in the same general vicinity of 2.4GHz. In the case of Wi-Fi, it uses those signals to transmit data. In the case of a microwave, it uses those same waves to cook food. Ideally, those waves should be contained entirely within the microwave oven, but invariably some seep out, because microwaves emit those waves at such an incredibly high power. The result: Even though the leak level is very small, it's enough to garble sensitive network equipment, and wireless networks get confused by the extra (gibberish) traffic on the 2.4GHz band. The result is that they either slow down or drop your signal altogether.

There's a lot you can do to help things here. The simplest is to simply separate the microwave from your network by sheer distance. The further the two are apart from one another, the less interference there will be, though that interference does extend a lot farther than you'd think (at least 30 feet and even further in many cases). Of course, this interference will only occur when the microwave is actually running, so if this is just an interruption while you're making popcorn, maybe it's something you'll find you can live with.

The only other solution aside from distance is to upgrade your equipment. Newer microwave ovens leak less radiation, while newer Wi-Fi gear (802.11n, particularly), can better handle that interference. I can use my laptop on the kitchen counter and nuke some Hot Pockets with no problem, for example, as both my microwave and Wi-Fi gear are relatively new.

If that still doesn't help, you can do one foolproof thing to eliminate microwave interference altogether: Switch to 802.11a Wi-Fi equipment. 802.11a is an old standard that works on the 5GHz band. It's considerably slower, but it isn't subject to interference issues like other Wi-Fi equipment is. (Note that microwaves aren't the only thing operating at 2.4GHz. Cordless phones, remote control toys, wireless speakers, and even baby monitors can be found clogging up this radio band.)

To your final question, is all of this dangerous? Well, people have been backing away slowly from their microwaves for years, afraid they're going to be "nuked" in the literal sense. But 2.4GHz radiation isn't anything like nuclear radiation; and no studies have found any serious medical effects from microwave radiation leakage. (And this is now a  technology that's been in mass acceptance in the U.S. for 30 years.) Some studies have found some correlation between microwave exposure and conditions like cataracts, but we use microwaves in such small amounts and the radiation leakage is so incredibly small in human terms that experts say there's nothing to worry about. Think of it as what they used to say about sitting to close to the TV.