Wireless Interference and Obstacles

Wireless interference is anything that makes a wireless signal less clear. Wireless signals travel as radio waves, so they can be disturbed by other electrical devices, by nearby wireless networks, and by physical objects in the way.

Sources of interference

Common sources include:

• Other electrical devices — a microwave oven, a cordless phone or a faulty power supply can give off radio waves that mix with your signal.
• Nearby wireless networks — in a block of flats, several home Wi-Fi networks and Bluetooth devices may interfere with each other's signals.
• Walls and solid objects — brick, concrete and metal absorb or reflect the signal, so less of it reaches the device.

What interference does

When interference is present, signal quality drops: the signal is less clear and more likely to be corrupted. This can lower the speed at which data is transferred, because devices spend more time checking and resending data. It can also increase latency, the delay between sending and receiving data, and reduce the range — the distance over which the connection still works reliably.

Distance, obstacles and blind spots

Signal strength generally falls as you move further from the access point. A thick wall or a metal cabinet makes this worse, even if the connection does not drop completely. A blind spot is an area where the signal is too weak for a reliable connection. For example, a tablet in a café may stream video smoothly near the access point, but behind a thick brick wall in the back room, the video may pause, files download more slowly and the connection may fail altogether.