How does Wi-Fi actually work?

Wi-Fi transmits data as radio waves between your device and a wireless router, which is connected to the internet through a wired link. The router encodes data by modulating the radio signal, your device decodes it, and the exchange runs in both directions many times per second. The frequencies used are unlicensed bands, principally around 2.4 gigahertz and 5 gigahertz, with newer equipment adding 6 gigahertz. Nothing about the radio link determines your internet speed beyond the router: Wi-Fi is the last few meters, and a fast wireless connection to a slow internet service is still slow, which is why speed tests on a phone measure both together and confuse the diagnosis.

The band tradeoff explains most home Wi-Fi problems. Lower frequencies penetrate walls and travel further, so 2.4 gigahertz reaches the back bedroom while 5 and 6 gigahertz often do not. Higher frequencies carry more data and are less congested, so they are faster where the signal reaches. The 2.4 band is also shared with microwave ovens, cordless phones, Bluetooth devices, and every neighbor's router, which is why it is often crowded in apartment buildings. Modern routers advertise both bands under one network name and move devices between them automatically.

Practical improvements in rough order of return. Position the router centrally, elevated, and away from metal, appliances, and thick walls, since placement in a closet or behind a television is the most common self-inflicted problem. Update the firmware. Change the channel if you are in a dense area, since congestion rather than signal strength is often the limiting factor. Use a wired connection for stationary devices that need reliability. For larger homes, a mesh system with multiple nodes outperforms a single powerful router. On security, use WPA3 where available or WPA2 otherwise, never WEP, set a strong network password, change the router's administrative login from the default, and treat a guest network as the correct place for visitors and smart home devices.