RT-AC68U Channel scans since firmware upgrade to 3.0.0.4.384_45713

[RL41]

I have an Asus RT-AC68U router. I am largely (not entirely) using default settings, and am using 5ghz wireless only (2.4ghz is turned off). I have Channel Bandwidth set to 20/40/80, and -- importantly for my question -- Control Channel Select set to Auto. I am not using AiProtection, QoS, or the cloud app.

My question: Since upgrading the firmware a few days ago to 3.0.0.4.384_45713, I see in the log that the router is scanning for a channel every 15 minutes, but *only* when there are no wireless clients connected (which is basically overnight, all night). Fyi it has been choosing channels 153 and 157 about 40% of the time each, and channel 36 the remaining 20% of the time.

At first I thought that this was a problem introduced by the new firmware, but now I am wondering if it is normal and I have simply never noticed it before. (I am definitely not a power user, and rarely check the log, except during my initial setup days about four months ago.)

Any thoughts on whether this is normal, or what I should do if not, would be greatly appreciated.

 

[RL41]

I've been looking this a bit more, and I further fail to understand why the only channels selected by the RT-AC68U during the quarter-hourly searches (when all wireless clients are off) are 36, 153 or 157. I downloaded Nirsoft WiFiInfoview, and see that those are each associated with 10-15 SSIDs, while some other 5G channels available in the Asus firmware appear far less. For example, channel 40 (0 times), 48 (5), 149 (3), and 161 (3).

 

[Grisu]

They changed something in the last release, allowing DFS channels and so they are scanning now.
Better to find your best channel and set it!

 

[RL41]

Thanks for that info. For now I've just set it to channel 40, and all seems well. But I'm still curious as to why autoselect seems to limit the the selections to 36, 153, or 157 -- doubly so since they seem to be rather crowded channels where I'm located. Interestingly, none of these -- or 40 -- are DFS according the the following link. And I also wonder if anyone else has seen the scan-every-15-minutes (when no wireless clients are connected) behavior for autoselect (although I gather from perusing the forum that autoselect is not favored here).

https://netbeez.net/blog/dfs-channels-wifi/

 

[Grisu]

ch 36-48 ar none DFS, but they got only 200mW power while >149 have 1W in US, thats why they can cover much more area and are preferably used in US.

Other thaughts about auto-channel: All your surrounded networks may move to another channel too if your router changes the channel and so all the year they are conflicting each other again and again.
Better to have them on a known fix channel and others will move away from yours, may last some time as they often select a new channel only after a reboot.