Chapter · Wi-Fi
The air
A frame sent through the air to everyone in range, radio waves and the channels of the 2.4 GHz band, and why signal is not a bar count.
- 01A frame without a cable4 minWi-Fi sends the same kind of frame as Ethernet, with the same kind of address, through the air instead of down a cable. Everyone near enough on the channel receives it, and the address decides who keeps it. This course pictures that as a ripple tank, and says where the picture stops.
- 02Radio waves and channels5 minWi-Fi at 2.4 GHz is a radio wave about 12 cm long. The band is cut into channels 5 MHz apart, each about 20 MHz wide, so neighbouring channels overlap, and which ones a board may use depends on the country.
- 03Signal is not a bar count4 minSignal is a number in dBm, and every 10 dB is ten times the power. Distance, walls and reflections change it, and a strong signal still says nothing about how busy the channel is.
Start at 01 and read down — the order is the order things get easier in. Or take the one with your part in it; every article stands on its own, and links back to whatever it needs.