Wi-Fi

Wi-Fi is the wireless networking technology (IEEE 802.11 standard) that connects devices to your router without cables. It transmits data as radio waves at specific frequencies, with devices and access points taking turns transmitting on a shared channel. Wi-Fi adds overhead compared to wired Ethernet — typically 20–40% lower throughput and 5–20 ms higher latency — but is essential for mobile devices.

Wi-Fi standards timeline

2.4 GHz vs 5 GHz vs 6 GHz

2.4 GHz travels further and penetrates walls more easily because lower-frequency radio waves lose less energy passing through solid objects. The trade-off is a crowded spectrum: every nearby router, microwave oven, baby monitor, and Bluetooth device competes for the same 100 MHz of space. Only three non-overlapping 20 MHz channels exist (channels 1, 6, and 11). Using any other channel causes adjacent-channel interference with neighbours.

5 GHz offers significantly more spectrum — up to 500 MHz of usable space across 25 non-overlapping 20 MHz channels in the US — resulting in less congestion and higher throughput. The shorter wavelength attenuates faster through walls, limiting effective range to about 10–15 metres in typical residential construction.

6 GHz (Wi-Fi 6E and Wi-Fi 7) adds another 1,200 MHz of clean spectrum with no legacy devices competing for it. It provides the most channels and lowest interference but has the shortest range of the three bands. Best suited for devices within the same room or adjacent rooms to the access point.

Channel overlap and interference on 2.4 GHz

The 2.4 GHz band spans channels 1–13 (1–11 in the US), each 20 MHz wide but spaced only 5 MHz apart. This means channels overlap heavily — a router on channel 3 interferes with channels 1, 2, 4, and 5. The only channels that do not overlap each other at all are 1, 6, and 11. Always set your 2.4 GHz radio to one of these three. Use a Wi-Fi analyser app to see which channel neighbours are using, then pick the least congested of the three.

Wi-Fi security: WPA2 vs WPA3

WPA2-AES (Wi-Fi Protected Access 2) has been the standard since 2004. It is secure against remote attacks when a strong password is used, but vulnerable to offline dictionary attacks if someone captures the handshake and your password is weak.

WPA3 (2018 onwards) replaces the PSK handshake with SAE (Simultaneous Authentication of Equals), which is resistant to offline dictionary attacks even with weaker passwords. It also provides forward secrecy — past sessions cannot be decrypted even if the password is later compromised. Use WPA3 if all your devices support it; use WPA2/WPA3 mixed mode if you have older devices.

Factors affecting Wi-Fi speed

• Distance — signal strength drops as the inverse square of distance; doubling your distance roughly quarters signal power
• Walls and obstructions — a single concrete or brick wall can reduce 5 GHz signal by 15–20 dB, which may cut throughput by half or more
• Interference — neighbouring networks, microwaves, and cordless phones on 2.4 GHz all compete for airtime
• Client capability — a Wi-Fi 6 router paired with a Wi-Fi 5 device negotiates at Wi-Fi 5 speeds; the bottleneck is always the older device
• Number of active devices — Wi-Fi is a shared medium; all devices on the same band and channel contend for the same airtime

Wi-Fi 6, 6E, and 7 key improvements

OFDMA (Orthogonal Frequency Division Multiple Access) allows a single transmission to serve multiple clients simultaneously by subdividing channels into resource units, dramatically improving efficiency in dense environments (apartments, offices).

MU-MIMO (Multi-User Multiple Input Multiple Output) allows the access point to transmit to multiple clients at once using multiple antenna streams. Wi-Fi 6 supports 8×8 MU-MIMO vs Wi-Fi 5's 4×4 downlink-only MU-MIMO.

BSS Colouring reduces interference from neighbouring networks by tagging transmissions, allowing devices to ignore traffic that belongs to a different network even on the same channel.

Wi-Fi 7's multi-link operation (MLO) allows a device to send and receive simultaneously across multiple bands (e.g., 5 GHz and 6 GHz), reducing latency and increasing reliability — a significant improvement for gaming and video calls.

Frequently Asked Questions

Why is my Wi-Fi slower than my Ethernet?

Wi-Fi is half-duplex (cannot send and receive simultaneously), subject to interference, and adds protocol overhead. A device 3 meters from the router on Wi-Fi 5 typically gets 60–80% of the wired speed. At 10 meters through two walls, expect 30–50%.

Should I use 2.4 GHz or 5 GHz Wi-Fi?

Use 5 GHz for devices within 8–10 meters of the router — it is faster and less congested. Use 2.4 GHz for devices at longer range or through many walls, where the 5 GHz signal cannot reach reliably.