Wi-Fi networks interfere with each other. Older Wi-Fi standards are even worse about this, so your old Wi-Fi hardware isn’t just hurting your network — it’s interfering with your neighbors, too.
All that interference is bad for everyone’s network, even yours. Unless you live out in the country with no one else around, this is something you need to think about.
Wi-Fi Channel Interference
All routers must operate their Wi-Fi network on one of several “channels” — different ranges of frequencies the wireless network can operate on. If you have multiple Wi-Fi networks near each other — and you probably do unless you don’t live near anyone else — they should ideally be on different channels to reduce interference.
Modern routers often try to automatically choose the best Wi-Fi channel for the least interference, but you can get some benefit from analyzing the airwaves around you and choosing the least congested Wi-Fi channel. If you and your neighbors are using the same Wi-Fi channel — especially if their wireless router is very close to yours — your Wi-Fi networks are making each other’s worse. Follow our guide to choosing the best Wi-Fi channel for instructions.
2.4 GHz vs. 5 GHz
Older 802.11b/g/n networks use the 2.4 GHz range. These networks in common use are not ideal for Wi-Fi channel interference. While there are 14 different available wireless channels designated for use in this range, they actually overlap quite a bit. Channels 1, 6, and 11 are most frequently used so Wi-Fi networks on adjacent channels don’t interfere with each other. If you have more than three wireless networks in an area — and you probably do — they’re just interfering with each other. You can’t really do anything about that unless you want to coat the walls of your house or apartment with tinfoil to ensure your neighbors’ Wi-Fi signals don’t interfere with yours.
Modern Wi-Fi standards operate on 5 GHz instead of 2.4 GHz. 802.11ac operates on only 5 GHz. 802.11n routers can operate on either 2.4 GHz or 5 GHz, but not both — and they’ll typically be set up to operate on 2.4 GHz. (Note: Single-radio 802.11n routers can only operate on the 5 GHz or 2.4 GHz range. However, there are multiple-radio 802.11n and 802.11ac routers that can create both 2.4 GHz interfaces for your older devices and 5 GHz ones for your newer devices.)
Where 2.4 GHz Wi-Fi offers only three non-overlapping channels, 5 GHz Wi-Fi offers 23 non-overlapping channels. This doesn’t mean interference is eliminated — if you’re sharing one of those channels with another 5 GHz WI-Fi network nearby, there will be interference — but it’s a much less congested range with more room for various Wi-Fi networks to spread out and not interfere with each other. If you and a bunch of your neighbors are all using 2.4 GHz Wi-Fi, you’re all getting a lot less interference if you upgrade to 5 GHz Wi-Fi networks.
Devices Interfering on 2.4 GHz
A variety of reasonably common devices also interfere on the 2.4 GHz Wi-Fi spectrum. These are an obstacle to having a fast, reliable Wi-Fi network. Even if you don’t have any of these devices, your neighbors might have them — although the interference will be worst when they’re closest.
Many cordless phones operate on the 2.4 GHz range, as do a variety of wireless “baby monitors.” Microwave ovens can also add interference here. Not all phones or baby monitors will interfere — only the 2.4 GHz ones. But, while you might be able to avoid these devices in your own apartment or house, your neighbors might have other ideas. There’s less interference on the 5 GHz range, which is another good reason to upgrade.
802.11b Devices Slow Down Newer Networks
Just having a device running an older wireless standard nearby won’t slow down your network, despite rumors otherwise. If your neighbor is using an ancient 802.11b device on their network, your network won’t see any slow-downs because of that — assuming they’re on a different wireless channel
Using an old 802.11b device on a modern 802.11g or 802.11n network will slow down the network as modern devices have to resort to dirty hacks to avoid breaking the old 802.11b device. If you have an 802.11b device on the same network, that’ll slow things down for everyone on that network. If there are multiple networks on the same wireless channel, the 802.11b device can also slow down networks on the same channel.
On the other hand, using an 802.11g device on a faster 802.11n network won’t slow things down in the same way. More modern wireless network standards handle this in a more sane way, so you only really need to worry about replacing those ancient 802.11b devices. And yes, those devices are quite ancient in consumer technology terms — 802.11b came out back in 1999, and it was replaced by 802.11g back in 2003.
Your neighbors can use 802.11b devices all they like without bothering you — assuming your Wi-Fi network isn’t sharing a channel with theirs. This is yet another reason to switch to 5 GHz Wi-Fi, where those 802.11b devices can’t go.
No, you probably won’t upgrade just to help your neighbors. But that interference isn’t just bad for your neighbors — it’s two-sided, and it means your neighbors’ Wi-Fi is also interfering with yours. Upgrading helps everyone.