Find and fix Wi-Fi problems, extend range and increase internet speed with our complete guide for your wireless network
How to detect and fix Wi-Fi interference
You might not need to buy a new router if you can fix the interference problems you’re suffering. By reconfiguring your router and changing some of its more simple settings, you may find that your Wi-Fi troubles go away. We’ll show you how to set up 2.4GHz and 5GHz networks properly. If you’re still having interference or range problems, you may need some new hardware, but we’ll cover all of that in the next section.
As we mentioned in the intro, positioning can be one of the biggest problems with Wi-Fi speeds. If you put your router in the wrong place, you may be artificially hampering its performance.
For the sake of testing, put your router close to your master phone socket to eliminate any issue of wiring. Take it off a metal shelf, if positioned on one. If it’s wall-mounted on a brick wall, try taking it off. Finally, try repositioning the router and seeing if that improves the signal, and you may be surprised at the results.
Choosing the right Wi-Fi channel
Although your router will run on a frequency band, such as 2.4GHz, underneath it’s actually only using a 20MHz slice of the frequency, called a channel. For example, channel 1 for 2.4GHz networks uses the 20MHz slice between 2,412MHz and 2,432MHz. Unfortunately, most of the 2.4GHz channels overlap, causing interference: channel 2 uses 2,417MHz to 2,437MHz, for example.
The illustration below shows you how the channels stack up. All of the channels coloured the same colour don’t overlap. Typically, people suggest using channels 1, 6 and 11, as these are these channels work everywhere in the world (12 and 13 are restricted in some places, although not the UK) and don’t overlap.
It’s not always that simple, though, as plenty of people don’t follow this simple rule; for example, you may be surrounded by people using Channel 2, which overlaps both Channel 1 and 6. Picking the right channel isn’t just about making the right decision based on technical data, but picking the right channel based on the networks around you, then.
Fortunately, this problem has been fixed with 5GHz networks, which has more channels, none of which overlaps. However, a neighbour maybe running a network on the same channel, causing interference issues. For both 2.4GHz and 5GHz networks, the trick is to set your router to use a channel different (where possible) to other wireless networks within range and one that doesn’t overlap.
This isn’t a perfect science and sometimes the interference or problems are caused by devices that you can’t detect, such as a baby monitor or wireless doorbell. As a result, you may need to change channels a couple of times to see any improvement.
The first place to start is with a Wi-Fi Scanner for your computer. These scan for wireless networks within range and tell you which channel they’re running on, and the base frequency (2.4GHz or 5GHz). WiFi Scanner for Mac (£19.99) is a brilliant and useful tool. For Windows, you can use inSSIDer Home (free). This has been replaced by a newer paid-for version, but the old version still works perfectly well.
Alternatively, Windows users can use WiFi Channel Scanner (free). This only shows you the channel of the network, not the frequency, and has an odd quirk with 5GHz networks, but it’s still possible to work out what’s going on. Channels 1 to 13 are 2.4GHz networks, while channels 36 and above are for 5GHz networks. However, WiFi Channel Scanner doubles the channel number for 5GHz networks, so channel 72 is really channel 36. There are no Wi-Fi scanners for iOS, as Apple had these removed from the App Store. Android is more permissive, so you can use Wifi Analyzer.
Run your chosen tool and let it gather information on nearby wireless networks. You can usually sort by channel, which gives you a better view of what’s going on.
For 2.4GHz networks, look at the most used channels. For example, you may find that most of your neighbours are using channel 1. Using the chart above you can pick an uncongested channel farthest from the one most used. In this example, channel 11 would be ideal, but channel 6 would also work.
There’s nothing to stop you using Channels 7, 8, 9, 10, 12 or 13, as these don’t overlap Channel 1. We don’t recommend that you do this, though. Part of owning a wireless network is being a good neighbour and picking a channel that doesn’t cause too much interference. In other words, look at the channel with the greatest concentration of wireless networks, then use our chart to pick an alternative channel of the same colour; this will make it easier for other people to add or configure their networks, too.
Note that in some areas, there are so many wireless networks using all kinds of channels that it’s impossible to choose a channel that doesn’t overlap any others. You may find, for example, that some routers around you are using channels 2, 3, 4 and 5, as well as 1. In this case, you’ll need to pick a channel that doesn’t overlap the most congested area, so channel 11 in this example. Ultimately, with so many wireless networks around, you may just have to pick the channel that gives you the best result, regardless of the consequences for other people.
For 5GHz networks, overlap’s not a problem, but general congestion could be. Note down which channels are the busiest: you should avoid using these channels on your home network.
Configure your router
Now you understand which other networks might be interfering with your router, it’s time to reconfigure it, to improve speed. Tweaking the settings can make a massive improvement in both speed and reliability. As you’ll be changing wireless settings it might make more sense to connect your computer to your router via an Ethernet cable, so that you don’t experience any dropouts. The navigation below will let you select the type of router you have – dual-band and 802.11ac router owners should follow the instructions for both 2.4GHz and 5GHz network.