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Is there a guide for channel selection for 5 ghz band?

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lepa71

Senior Member
I'm wondering if there is a guide for channel selection for 5 GHz band. I understand that some have 20/40/80/160( in my AX3000) but the question is which one to pick.
As for 2.4, which I don't use much, I just set it to 1 or 6 or 11.

Any suggestions would be much appreciated.
 
I'm wondering if there is a guide for channel selection for 5 GHz band. I understand that some have 20/40/80/160( in my AX3000) but the question is which one to pick.
As for 2.4, which I don't use much, I just set it to 1 or 6 or 11.

Any suggestions would be much appreciated.
You will get a lot of suggestions...

For me I use Dual Band Smart Connect and pretty much leave the rest of the WIFI settings at default. As for specifics I do set the 5 GHz Auto Channel to 20, 40, 80, 160 MHz with WIFI 6 enabled. You can check the Auto select channel including DFS channels but more about this in a bit. For the 2.4 GHz band I set it to Auto Channel at 20 MHz. Authentication Method I set to WPA2/WPA3-Personal but WPA2-Personal works for most clients.

The reason I set the 5 GHz to Auto Channel at 20, 40, 80, 160 MHz is that at the 160 MHz settings the router will use some DFS channels. If the router detects RADAR the 5 GHz band will shut down for up to 10 minutes until the RADAR is cleared. At Auto Channel 20, 40, 80, 160 MHz the router will drop back to 80 MHz on a non-DFS channel and keep working. In fact I have found that the router will run at 80 MHz most of the time until an AX client connects then go to 160 MHz.

Some folks will say my settings do not work. But you spent the big bucks for a good router. Trust it to use the channels and bandwidth that works best for your network.
 
Some of the older hands around here may know better, but here's my understanding:

* Channel numbering in 5GHz is based on 5MHz-wide channels, just like in 2.4GHz. But no equipment uses less than 20MHz-wide channels, thus your choices are always 4 channel numbers apart. Partially-overlapping channels are not a thing here (thank goodness).

* 40MHz or wider channels are made by ganging adjacent channels. For example, if you choose channel 40 as your primary channel, your gear transmits in that channel until it has need for more than 20MHz bandwidth. When it does, it will combine the 36 and 40 channels to make a 40MHz channel. If it needs more than that, it adds channels 44 and 48 to make an 80MHz channel. If it needs more than that, it adds the next 4 channels to make a 160MHz channel.

* If your neighbor is, say, using channel 44 as primary channel, your signals don't interfere as long as both of you need up to 40MHz bandwidth (because his first step up is to 44+48). As soon as either of you need 80MHz, you are transmitting on the same frequencies and only one of you can broadcast at a time.

* I use these particular channel numbers because, depending on where you live, they might be the only ones you can use. There is a second set of 4 available WiFi channels at 149/153/157/161, but not every country allows their use.

* The channels between 48 and 149 are theoretically available to WiFi gear, but with a huge caveat: that is the "DFS range" of frequencies which WiFi gear is only allowed to use if it cannot hear anything else broadcasting on the frequency. In particular, a big chunk of that range is used by aviation radar and weather radar. If you live anywhere near an airport or weather radar station, your gear will see the radar pulses and drop off the channel, probably for minutes at a time. If your primary channel is in this range, what "drop off" means is you've got no WiFi at all. If your primary channel is one of the safe ones I listed above, and your gear is well designed, it will just back down to using at most an 80MHz channel (using the four adjacent safe channels).

* A lot of people have found that that back-off doesn't work so well, so they just set their gear to not use more than 80MHz channel width ever.

* So in short: if you don't have any near neighbors using 5GHz WiFi, just choose any one of the safe channels and be happy. Try letting your gear use 160MHz bandwidth, but if it seems unstable, one of the first things to try is restricting it to 80MHz so it stays out of the DFS range.

* If you do have near WiFi neighbors ("near" being within maybe 100 yards/meters), you want to try to not share channels with them. Most consumer gear has provisions for auto-selecting a lesser-used channel, but it's not unusual for that mode to make stupid choices. You might have to manually choose a channel. Best case is if you're on the low channels and your neighbor's on high or vice versa; then you both can use 80 or even 160 MHz without overlap. Otherwise, at least try not to be sharing the same 40MHz channel pair.
 
BTW, what I said above was intended to be generic. If you're using a tri-band router (i.e. one 2.4GHz radio and two 5GHz radios), then that info applies to each 5GHz radio separately, and the upshot is that if you want 80MHz or wider bandwidth then you've got to have one radio using the lower band of non-DFS channels and the other radio using the higher band. In both the ASUS and Netgear routers that I've had, the software seemed to force use of the lower band for the client-facing 5GHz radio while forcing the backhaul radio to use the upper band. This is fine as long as you don't have to coexist with any nearby neighbors, but if you do then the lack of flexibility is problematic. I'm not sure if it's strictly a software problem or if the radios are actually built with limited tuning range.
 
I use channel 100 with 160mhz width. I’m 7 miles from a major international airport with a weather read station (KDTW). My pixel 6 connects at 160mhz and can use all of my 600mb service at times. Experiment and see what actually works for you
 

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question is which one to pick.
Download a WIFI analyzer app on your phone or laptop and see what's broadcasting around you to make an educated decision on what will work best.

I just downloaded Acrylic because someone else was asking about something similar and it's quite in depth for the info if you choose to be nerdy about things. It does also have a pane at the bottom for 5Ghz info.

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On the phone I can get more granular with channels / SSID's being used. This is a good start though to monitor your RF surroundings and seeing the results of the channel you're choosing.
 
Experiment and see what actually works for you

Can't argue with that, everybody's situation will be a little different.

FWIW, I'm about 25 miles from local airport & radar station, with a couple honkin' big hills in between, so I thought I could get away with using DFS channels. Nope, I got RADAR log entries every few hours. It would have been fine if my XT8s had gracefully backed off to 80MHz as they should, but they were more like total fail. At the time I was a raw newbie and didn't know any of the info sketched upthread, plus I didn't know that some ASUS firmware releases flat-out suck. Maybe if I went back and tried it with what I know now, and a more stable firmware version, I could make it play acceptably... but I'm happy with the setup I've got and don't plan to experiment further until some new gear comes down the pike.
 
Download a WIFI analyzer app on your phone or laptop and see what's broadcasting around you to make an educated decision on what will work best.
+1, if you have to worry about your neighbors at all, a scanner app is invaluable.
I just downloaded Acrylic because someone else was asking about something similar and it's quite in depth for the info if you choose to be nerdy about things.

In the Mac camp, I've had good luck with WiFi Scanner and NetSpot Pro.
 

This one looks familiar for use though they want to tie you to an account for gathering stats. I use a handful of different apps for WIFI / speed testing on my phone alone and not too many on the laptop up until now. With 6E not being on the phone the laptop should cover that aspect with Acrylic for the time being. There's not too many 6E phones out at the moment that seem worthwhile in getting. I'm anti Apple / Samsung when it comes to phones., It adds a bit of delay when trying to keep something in your pocket up to snuff with latest tech when you snuff the top 2 selling device OEM's from the list. 6E doesn't offer much more in terms of speed but, that sexy 6ghz spectrum is a temptress. @ $300 though for a device that gets the extra band of spectrum isn't all that appealing since I already get gigabit plus LAN + WAN. WIFI7 will be a perk though doubling the channels to 320mhz.
 
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