What’s the difference between… 2.4 and 5GHZ?

QIn as much as I don’t really know what my dual-band router is doing much of the time, and still less which band my laptop or tablet use to connect, I do often wonder what the practical difference is between the 2.4 and 5GHZ standards? I’m pretty sure my laptop must be 2.4GHZ because it’s quite old, but I can’t say internet stuff feels significantly slower than on my new ipad, which I assume connects via 5GHZ. So, could you explain in simple terms the difference between 2.4 and 5GHZ?

Alan Wright

AWe could write pages on this but space is limited! Fundamentally, they’re different parts of the radio spectrum. As a rule of thumb, the 2.4GHZ band enables greater range at slower speeds, while 5GHZ signals are able to transmit more, and faster, but over shorter distances. That’s because the laws of physics dictate that higher-frequency radio waves aren’t as good at passing through barriers, such as walls or doors.

In addition, there are numerous technical specifications that define the way computer data is sent and received by routers and the devices that connect to them. These are the various standards with 802.11 prefixes that you’ve probably seen referred to in print, online or on packaging.

An ancient 802.11b router, for example, is able to communicate only over the 2.4GHZ band – and at speeds of up to 11Mbps. By contrast, a more modern 802.11n router will be able to use either (or both) bands, and will typically offer speeds of up to a theoretical 600Mbps. The latest 802.11ac routers go faster still (up to 1300Mbps or 1.3Gbps) – though some manufacturers employ tricks to claim even higher speeds. The nextgeneration 802.11ax standard pushes these theoretical baselines even further.

Some people favour the 5GHZ band, simply because it offers more user channels and is considered less congested. Regulator Ofcom maintains an interactive ‘map’ of the UK’S radio- spectrum allocation. You can explore it at www.snipca.com/27717. However, in practice, most of the time most people don’t need to think or worry about any of this. Generally, modern wireless routers and the devices that connect to them find the best way to communicate with each other, be that over 2.4 or 5GHZ radio waves.