How does Wi-Fi work?

Wi-Fi is radio. Your router and your phone talk to each other using invisible radio waves, the same family of waves that carry FM music, only at a higher frequency.

Your phone turns the data it wants to send — a message, a video request — into a pattern of radio waves and beams it out. The router catches the pattern, turns it back into data, and sends it down the cable to the internet. The reply comes back the same way.

Wi-Fi waves are weak, by design, so they travel only 30 to 50 metres and are stopped by thick walls and water. That is why the signal drops in the back bedroom, and why a full water tank between you and the router is a problem.

The name does not stand for ‘wireless fidelity’; it was invented by a marketing company because ‘IEEE 802.11b’ was impossible to sell.