The Case of the Leaking Microwave

One of my hobbies is online gaming. The enjoyment derived from going with a group of friends to accomplish some difficult task in the game is gratifying. There can be some interesting frustrating situations that pop up in this scenario though. One of these is having a party member disconnect at a critical juncture. I had one particular friend, whom we call Tim, who often disconnected for no apparent reason. After a few weeks of observation, Tim realized that he would lose his signal every time one of his roommates would nuke anything in the microwave. This led to a lively discussion about whether or not a microwave should leak enough radiation to cause interference. After a little further research, I noted that this is a fairly common occurrence. Common enough that many related humorous articles and comics can be found including this XKCD comic.

A rather devious way to exploit a leaking microwave

Radiation? Is my microwave radioactive?

When radiation is mentioned, most often the first thought is of glowing green mutants and super heroes. Discounting the Hollywood influence, the next, more realistic, thought is of nuclear bombs and power plants. Radiation is a general term for energy that is emitted or ‘radiated’ from a given source. Microwaves fall into the category of non-ionizing radiation whereas radioactive materials such as uranium or plutonium emit waves that qualify as ionizing radiation. Non-ionizing indicates there is enough energy generated to jostle the electrons in the atoms around but not enough to remove them completely. Cells stay intact even though there is more activity going on internally. When enough energy is generated to push electrons out of stable atoms, this is categorized as ionizing radiation. Even more specifically, the radioactive materials used in power plants and bombs emit gamma rays. The chart from the EPA as pictured below lists several of the more common types of radiation and where they fall in the spectrum. Note that microwaves and gamma rays are a significant distance apart.

Types of radiation as illustrated by the EPA

Practically speaking, any microwaves that escape through the cracks and through the mesh display window won’t harm you any more than if you stood in front of your router. Even if you are concerned about these waves you can step back a few feet from the microwave. The few stray waves don’t travel very far before dissipating. Please note that these waves do transfer their energy to heat as they move through fats, oils, and water. If your microwave is damaged especially around the door, you will want to get it fixed.

Does my microwave leak? 

Most microwaves leak a little bit. If you are curious about whether or not your microwave leaks, one simple test you can perform is a ping test. The supplies you will need are as follows:

• Laptop or tablet with WiFi enabled 
• Microwave 
• Another PC, tablet, or laptop connected to the same network

Disconnect the power to your microwave. Make sure your portable computer is powered on and that the Wi-Fi is allowing proper communication. Place it in your microwave and close the door. Do not turn on the microwave. Proceed to your other device on the same network and run a ping for the laptop’s IP address. If you receive a response, your microwave leaks. If you receive a time-out response, your microwave is fairly well shielded.

Ok, so what do I do if my microwave is interfering with other electronics in my house? 

Most microwaves aside from a few industrial ones run at approximately 2.4 GHz. Because this is an unlicensed ISM (Industrial, Scientific, and Medical) frequency band, many other electronics utilize this band as well. Notably Wi-Fi and some cordless phones use this band as well. Unfortunately you cannot change the frequency your microwave runs at as it a very effective frequency for speeding up the activity of water molecules. However, you can look on the label inside of your microwave to figure out the center frequency that the device uses. (There is a range and microwaves do vary.) Once you have that information, you can adjust your router to operate on a frequency outside of the microwave’s operating range. You can also move your router or microwave even just a few feet. This can alter the paths of the RF waves throughout your environment and possibly reduce the interference.

Sources:
Jim Geier, Wi-Fi Planet, “Dueling with Microwave Ovens” http://www.wi-fiplanet.com/tutorials/article.php/3116531
EPA, Radiation, “Non-Ionizing and Ionizing” http://www.epa.gov/radiation/understand/index.html