In addition, here's some info regarding interference:
Sources of interference:
Microwave ovens: Using your microwave oven near your computer, Bluetooth device, or Wi-Fi base station may cause interference.
Direct Satellite Service (DSS) RF leakage: The coax cable and connectors used with certain types of satellite dishes may cause interference. Check the cable for damage and obtain newer cables if you suspect RF leakage.
Certain external electrical sources such as power lines, electrical railroad tracks, and power stations.
2.4 GHz or 5 GHz phones: A cordless telephone that operates in this range may cause interference with wireless devices or networks when used.
Video senders (transmitters/receivers) that operate in the 2.4 GHz or 5 GHz bandwidth.
Wireless speakers that operate in the 2.4 GHz or 5 GHz band.
Certain external monitors and LCD displays: Certain displays may emit harmonic interference, especially in the 2.4GHz band between channels 11 and 14. This interference may be at its worst if you have a portable computer with the lid closed and an external monitor connected to it. Try changing your access point to use 5 Ghz or a lower 2.4 GHz channel.
Any other "wireless" devices that operate in the 2.4 GHz or 5 GHz bandwidth (microwaves, cameras, baby monitors, neighbors wireless devices, and so on).
Note: Some devices may not overtly state that they operate in the 2.4 GHz or 5 GHz bandwidth. The operations manual should indicate the frequencies the device uses to operate. These may be referred to as "Dual Band" or "Wireless" devices.