Should WiFi routers be set to a channel or choose automatically?

Question

This question is about scenarios where many other independent routers are nearby, like in apartment buildings etc.

There are many articles online (like this one on lifewire) showing how to manually find a channel / frequency for routers to use, and getting a list of networks with channel numbers is simple (iwlist *interface* scan | grep \(Channel).

However, does it make sense to choose the channel manually if most other routers are set to choose automatically? Or will it make things worse after a short while, when other routers change channels?

Answer 1

It really depends on a couple of things:

1. Is it really a nice router? If so, it will probably do proper channel selection based on local usage/interference, and may even recheck when it restarts, in which case you probably want to set it to auto-selection. If it's a cheap router though, 'Auto' is almost always one of a couple predefined channels (for example, in the 2.4 GHz band in the US, 'Auto' usually means channel 1 or channel 8, or on rare occasion channel 6 or 11), and in that case check the next point.
2. How much interference are you actually seeing? Ideally, grab a Wi-Fi signal analyzer app for your phone, and see what channels are being actively used in your area. If your router is auto-selecting a channel that's in active use by just one other AP and that other AP has a weaker signal in the entire area you want covered, you're probably fine. If, on the other hand, you see multiple other APs on that channel or if another AP has a stronger signal than your router does in an area you need covered, you should probably look at manually specifying a channel instead of just letting the router choose one.
3. As a special case, if you're using WoWLAN (Wake on Wireless LAN) on your network, you almost certainly want to go to the trouble of specifying a channel manually regardless, as WoWLAN will stop working if your router changes the channel while a device is offline, and any interference can cause issues with WoWLAN.

Also, just a general tip when choosing a channel manually, try to find one that is as far from any other used channels as possible. With a few special exceptions like channel 14 in the 2.4 GHz band most channels partially overlap at least one other channel, so being as far from other channels that are in-use as possible will help reduce interference:

Image source: Wikipedia.

Answer 2

The answer depends on the router.

If you have a nice, quality router with updated firmware, "Auto" will do a quick scan for what channels have the least interference, and pick from the best option.

If you have a cheap router, it usually defaults to channel 6 or 8 if you choose Auto. Since that's what most people have, you end up with a whole neighborhood living on the same channel and wondering why their internet connection sucks, even though the ISP keeps telling them they're getting full speed when they test from the Modem.

I recommend getting an app for your cell phone that will tell you how many different wifi broadcast signals it detects per channel. I use one on my android device that shows me a graph of each device's strength from my location, and the Network Identifier for the device. Using this, I was able to discover that my neighbor's irritating WiFi speakers in his back yard were single-handedly tanking most of the connections for the surrounding houses on channel 6. I manually set my 2.4ghz bandwidth connection around this until I moved up to a 5ghz router, which put me well outside of locally used frequencies.

Answer 3

My opinion is to have them set up to automatic.

When most modern routers assign a channel, they do so by scanning the band and choosing one with the least interference. Setting yours manually would cause issue if there is already nearby routers on that channel, but when those others reset it will likely choose another channel.

Bear in mind though that here the frequency is more important. If you're running 2.4GHz, there's only three non-overlapping channels, so interference is likely regardless. Stick to the 5GHz and you should be fine.

Answer 4

For home routers I recommend setting them to Auto. In the majority of the cases they will find an open channel. As mentioned, go for the fastest speed your router will support. 5GHz has more options. 2.4 gives you 1, 6, and 11.

If you absolutely must search/set a channel yourself, then it would be quicker/easier if you go into your router settings and then manually set the channel. For 2.5GHz, start at channel 11 -- see how your router performs. If you are getting tanked, then move to 6 and so on. And placing it in a good central area in your home will help you get a solid signal in every room, generally.

Answer 5

I have an Asus RT-AC1900P at home and it rarely auto chooses either 1,6 or 11 in 2.4ghz. It often will choose an "in-between' channel. I'm currently seeing 7 different 2.4ghz AP's (not counting vacuum cleaners, printers, vacuum cleaners and thermostats)...and the routers choice is usually the best, even in-between. I've read all about how sticking to 1,6 or 11 is the best, and in an Enterprise, where you're building a wifi plan that certainly makes sense, but I think in a home environment when the neighbors are all over the place, it's best to just let the router find it's place by itself and call it a day. In my case, my AP is usually at least 30db greater anyway. Just be sure it's set to 20mhz bandwidth in 2.4ghz.

Answer 6

Do not set channels to automatic if you either have a really cheap WiFi transmitter or live in a very densely populated area and are solely using (old/cheap) 2.4ghz transmitters (it barely matters for any router capable of transmitting 5ghz, so don't worry about 2.4ghz or 5ghz channels in these routers. These are usually new routers and they have a lot less of these stability issues related to channels). This mostly has to do with channel saturation.

Just for people that are surrounded by other people (like an old flat with really thin walls), should analyze the channels and set them fixed if they run into stability issues.

The problem in densely populated areas is, when all people set it to auto and all are using a cheap or old transmitter, all of these transmitters will battle for the channels 1 to 8 and you can run into stability issues (cheap routers rarely select the best channel). It is possible they could select a less than optimal channel; like 2,3,4,5,7,8 where already everyone else is sitting. But fortunately, this is more an issue in old or really cheap WiFi routers. Modern routers rarely have issues with auto-channel selection even if it's "in-between" and shouldn't really matter where you live.

Answer 7

Don't use auto. Auto causes havoc with users that have taken the time to pick the best channel. Auto never switches when you are using the wifi. It only switches when you aren't using it. This makes it a game of chance when it comes time to use because who knows what interference there is at the time it's needed. Grab a cell phone or device that looks at the airwaves and pick the best channel with the least amount of users. Also interference from other users won't happen till they use their wifi and devices can drop their channel bandwidth from 80, 40 or 20 if there is interference. People seldom use a lot of bandwidth so if you do VOIP or use other time sensitive data, going with a 20mhz channel can sometimes make more sense over 80mhz. 80mhz is guaranteed to be more interference for bandwidth most people seldom use.