How to Boost Your Wi-Fi Speed by Choosing the Right Channel

Wireless networks have come a long way in the past couple of decades. And yet, sustained Wi-Fi speeds are still a vexing problem in a lot of situations. A number of subtle factors can come into play, including the way your router is set up, the presence of nearby interference, whether you live in an apartment building or a stand-alone house, where your microwave sits in relation to the rest of your network, and how far your devices are from the router. Fortunately, there's almost always a way to fix slow transfer speeds.

If you've ever messed around with your Wi-Fi router's settings, you've probably seen the word "channel." Most routers have the channel set to Auto. But many of us have looked through that list of a dozen or so channels and wondered what they are, and more importantly, which of the channels are faster than the others. Well, some channels are indeed much faster -- but that doesn't mean you should go ahead and change them just yet.

Channels 1, 6, and 11

First of all, let's talk about 2.4GHz, because even in 2021, the majority of Wi-Fi installations still use the 2.4GHz band in some way. 802.11ac, which debuted in 2013, is driving adoption of 5GHz, helped along by adoption of 2020's 802.11ax / Wi-Fi 6 -- but thanks to backwards compatibility, dual-radio routers and devices, and lower-cost peripherals with less expensive chipsets, 2.4GHz will continue to reign for a while.

All versions of Wi-Fi up to and including 802.11n (a, b, g, n) operate between the frequencies of 2400 and 2500MHz. These 100MHz are separated into 14 channels of 20MHz each. As you've probably worked out, 14 lots of 20MHz is a lot more than 100MHz -- and as a result, every 2.4GHz channel overlaps with at least two, if not four, other channels (see diagram above). And as you can probably imagine, using overlapping channels is bad -- in fact, it's the primary reason for poor throughput on your wireless network.

What channel should you use in a crowded area?

For example, if you're using channel 1, but someone next door is annoyingly using channel 2, then your throughput will plummet. In that situation, you would have to change to channel 11 to completely avoid the interference (though 6 would be pretty good as well). It might be tempting to use a channel other than 1, 6, or 11 -- but remember that you will then be the cause of interference (and everyone on 1, 6, and 11 will stomp on your throughput, anyway).

In an ideal world, you would talk to your neighbors and get every router to use channels 1, 6, or 11. Bear in mind that interior walls do a pretty good job of attenuating (weakening) a signal. If there's a brick wall between you and a neighbor, you could probably both use channel 1 without interfering with each other. But if it's a thin wall (or there's lots of windows), you should use different channels.

There are tools that can help you find the clearest channel, such as Vistumbler(Opens in a new window). But it's probably faster to just switch between channels 1, 6, and 11 until you find one that works well. (If you have two laptops, you can copy a file between them to test the throughput of each channel.)

But what about 5GHz?

The great thing about 5GHz (802.11n, 802.11ac, and Wi-Fi 6) is that because there's much more free space at the higher frequencies, it offers 23 non-overlapping 20MHz channels. 6GHz should continue this trend, with even more frequency space (although with slightly worse propagation characteristics).

Starting with 802.11n and continuing with 802.11ac, wireless technology in general became much more advanced than the prehistoric days of 802.11b and g. If you own at least a decent 802.11n or 802.11ac router (i.e. if you bought a router in the last several years), it likely has some hardware inside that chooses the right channel automatically and modifies the output power to maximize throughput and minimize interference.

If you're using the 5GHz band, and your walls aren't paper-thin, then attenuation and the general lack of 5GHz devices should mean there's little interference in your apartment -- possibly even allowing you to use the fatter 40, 80, and 160MHz channels if you feel like it.

Eventually, as everyone upgrades to newer hardware and moves towards 5GHz, picking the right channel will mostly become a thing of the past. There may still be some cases where it makes sense to fine-tune your router's channel selection. But when you're dealing with MIMO setups (up to eight in 802.11ac), it's generally a better idea to let your router do its own thing. Eventually, of course, 5GHz will fill up as well -- but hopefully by then, we'll have worked out how to use even higher frequencies (60GHz WiGig) or entirely new antenna designs (pCells, infinite capacity vortex beams) to cope with our wireless networking demands.

WiFi 6E will eventually change some of this guidance, but right now the only WiFi 6E devices are poor deals. Once Wi-Fi 6E hardware is available, the 6GHz band is expected to create opportunities for clearer networking since it's unused spectrum at the moment. Total performance of WiFi 6E is not higher than WiFi 6, but it should be easier to hit that throughput in real-world scenarios.

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