Electromagnetic Interference

What is EMI? : Electromagnetic interference is a common problem for those who use wireless signals, such as wi-fi Internet and/or radio signals. Also known as RFI (Radio frequency Interference), it’s usually caused by an external device that is releasing electromagnetic radiation. There are a variety of devices that can cause EMI, among them include:
Cell phones: The device for the working man on the go, it allows the user to receive a phone call while they are in range of a cellular network. The mild radiation it releases will sometimes cause some static and signal problems, the radiation has also been linked to causing a noticeable drop in a humans ability to suppress his or hers allergies, as well as causing what was previously known as "Tennis Elbow". (Due to the elbow holding the hand in an upright position for prolonged periods of time) It can be reduced in a workplace by having a no cell phone policy, any other way would require either electronic jamming, (which is illegal) or by using special signal-trapping paint (Which is not illegal). However, these both obviously also stop you from using your wireless device, so it’s really a double-edged sword.
Microwaves: One of the more notorious ones. While certainly annoying, it lacks the power to fully cripple a wireless signal. However, due to it’s common use many know of its annoying tendency to create static, especially among wireless home phone users. Keeping a wireless phone receiver in a different room then where the microwave is will definitely help, as a microwaves emissions aren’t nearly powerful to penetrate a wall.
EMPs (Electromagnetic Pulses): A very rare form of EMI, these are usually created when a nuclear bomb is set off. They are also created by what are known as "Pinches", a device that was made to re-create the effects (Usually for studying purposes) of an EMP released with the denotation of a nuke, while avoiding all of the messy destruction and environmental activists complaints. There isn’t much one can do about this, other then make sure they don’t live near a government testing facility, as it is more then powerful enough to thwart most standard EMI protection. In more sensitive electronics, it can even completely fry/destroy the internal parts of the device.
Magnetrons: An extremely powerful magnet, they can completely shut down a small area of sensitive electronic devices. However, they require a current to be running through them in order to create the interference. The more power, the larger and more potent of the electromagnets interference. Depending on the quality of the material, it will be able to create a larger area of interference with less power. They’re usually made of Ferro-magnetic elements such as Iron. By cutting off a magnetrons power supply, you eliminate it’s potential to cause EMI.
Generally, Electromagnetic Interference can be minimized (Or possibly eliminated) by a number of different methods. The most obvious one being just simply not using a EMI causing device near a susceptible wireless signal device. There are also materials and devices that help to reduce EMI emissions, or protect your device from EMI.