As the name goes, Wi-Fi extenders simply piggyback on your existing Wi-Fi connection and rebroadcast it so further away places can get a stronger signal.
They won’t reach as far as wired connections and they won’t improve your overall network speed, but if you simply want to ensure the top floor of your house finally has some signal they’re a really easy option. Generally they’re cheaper and less hassle than any alternative.
Most offer simple automated setup procedures, with them either connecting automatically using WPS or having their own open network to which you connect to then configure them through a browser. Generally you only need to know the SSID of your existing Wi-Fi and its password to get setup.
The main consideration with Wi-Fi extenders is what sort of Wi-Fi standard you need. Now things have become more complicated with two radio frequency bands available – the older 2.4GHz and newer 5GHz – as well as a new standard called AC. On top of that there are different rated speeds for Wi-Fi N and AC, ranging from the basic 300Mbps of N right the way up to routers that claim 1900Mbps.
Aside from speed the next possible extra you might consider is an extender with an in-built Ethernet switch. These models will enable you to connect wired devices to the extender, such as an older network-equipped TV, and potentially help improve overall speed because there will be fewer Wi-Fi signals interfering with each other.
A few models also have USB sockets so you can attach printers or external hard drives to share them on the network. Some even have audio outputs so you can plug them into a remote audio system and stream audio from your phone or tablet.
Most range extenders are fairly simple devices that, like Powerline adapter, are incorporated into a single mains plug/transceiver, though those with more features and external aerials (for greater range and performance) look like routers, with a separate power supply and external aerials.
At the heart of the latest push for speed in Wi-Fi is the introduction of a 5GHz frequency. Its main advantage is that nearly all existing Wi-Fi devices use the 2.4GHz band, which makes it highly congested. By using 5GHz you’re far less likely to get problems with interference from neighbouring Wi-Fi signals.
The 5GHz band actually has a lower theoretical range than 2.4GHz so drop off at distance (and through walls) is much more dramatic. However, the latest AC standard only uses 5GHz, combining it with techniques such as MIMO and beamforming to improve peak performance and range. As such, as shown in our tests, a top-notch 5GHz AC router provides very fast performance, even at long distances. So much so that if you’re thinking of upgrading your router anyway, spending the extra on a top-notch one may well eliminate the need to buy an extender.