The Wireless 5GHz channel has dropped from 160Hz to 80Hz

[kidd232]

Model: GT-AX6000, Firmware: 3004.388.6 Beta

I've noticed that sometimes my WiFi automatically drops from 160Hz to 80Hz.
I understand that during radar scanning, WiFi automatically switches to 80Hz, but under normal circumstances, should it switch back to 160Hz once the time elapsed countdown is complete?
However, my time elapsed has already counted down, yet it hasn't switched back to 160Hz.

Please refer to the attached settings and status. Is there a problem with my GT-AX6000?

 

[ColinTaylor]

Your router has switched to channel 161 which only supports a maximum bandwidth of 80MHz. AFAIK once it's changed channels it won't switch back again. It will only move if it detects more interference on the current channel.

 

[sfx2000]

Your router has switched to channel 161 which only supports a maximum bandwidth of 80MHz. AFAIK once it's changed channels it won't switch back again. It will only move if it detects more interference on the current channel.

But his control channel in the screen shot is 36, so that's kind of odd that the router would hop up to 161...

 

[ColinTaylor]

But his control channel in the screen shot is 36, so that's kind of odd that the router would hop up to 161...

Yes the inner workings of Broadcom's algorithms is mysterious indeed. When I was running my previous router on a fixed 100/160 it would frequently jump to 56/80 when it detected radar activity. It just seemed to like that channel.

 

[sfx2000]

Yes the inner workings of Broadcom's algorithms is mysterious indeed. When I was running my previous router on a fixed 100/160 it would frequently jump to 56/80 when it detected radar activity. It just seemed to like that channel.

That smells like a bug - I get it that 160MHz channels will go into the DFS zone, and if they get a radar hit, it should vacate the channel for a time, but it shouldn't just jump the control channel away from what the UI has set if the control channel is not a DFS channel.

Very odd...

 

[Tech9]

Is there a problem with my GT-AX6000?

Firmware: 3004.388.6 Beta

You are you testing your router with a 3rd party Beta firmware?

 

[kidd232]

You are you testing your router with a 3rd party Beta firmware?

I have always been using Merlin firmware and running some services.
In fact, this issue has been present in the previous official merlin versions, but it didn't occur frequently.

Perhaps recently, there are more "radar scans" in my area, and it drops to 80Hz every 2 days or so.
Every time, I need to reboot to get back to 160Hz, which is why I posted a query.

 

[RMerlin]

I have always been using Merlin firmware and running some services.
In fact, this issue has been present in the previous official merlin versions, but it didn't occur frequently.

Perhaps recently, there are more "radar scans" in my area, and it drops to 80Hz every 2 days or so.
Every time, I need to reboot to get back to 160Hz, which is why I posted a query.

If in your area you are getting bumped off that channel every two days, then it's probably pointless to continue trying to use that same wide channel, as you will face a high chance of getting constantly disconnected again as radar activity will occur again on a regular basis - it's not just a random occasional event.

160 MHz channel width stability is never guaranteed as it depends on your environment. In my location, my router is rock stable using a 160 MHz channel because my environment never gets any DFS activity.

 

[robinjoo1]

channel 36 is a non-dfs channel so i dont get why it would switch

 

[Tech9]

I have always been using Merlin firmware and running some services.

This is fine, but the firmware you are using is for testing purposes only.

Perhaps recently, there are more "radar scans" in my area, and it drops to 80Hz every 2 days or so.

Your Wi-Fi environment perhaps changed and you can't use DFS range anymore.

 

[RMerlin]

channel 36 is a non-dfs channel so i dont get why it would switch

There is only 80 MHz of space within that band. To reach 160 MHz of channel width, you need to extend into the U-NII-2A band, which is DFS frequency territory.

See the Wikipedia chart: https://en.wikipedia.org/wiki/List_of_WLAN_channels#5_GHz_(802.11a/h/n/ac/ax)

 

[ColinTaylor]

There is only 80 MHz of space within that band. To reach 160 MHz of channel width, you need to extend into the U-NII-2A band, which is DFS frequency territory.

See the Wikipedia chart: https://en.wikipedia.org/wiki/List_of_WLAN_channels#5_GHz_(802.11a/h/n/ac/ax)

True. But I think the issue that @sfx2000 highlighted was: If there's interference detected on DFS channels 52 to 64, and it's going to change the bandwidth to 80MHz anyway, there's no need for it to change the primary channel at all. It might as well stay on channel 36 and drop the bandwidth to 80MHz.

I think the reason might be that (AFAICT) the wireless driver is constantly monitoring the other channels, not just the channels it's using. So when it needs to change the chanspec it thinks that (in the OP's case) channel 161/80 is a better choice than 36/80 and so moves there. Just guessing though.

 

[MDM]

It seam logical to monitor all the Channel's Utilization (and interference), and decide upon that factor...

 

[robinjoo1]

There is only 80 MHz of space within that band. To reach 160 MHz of channel width, you need to extend into the U-NII-2A band, which is DFS frequency territory.

See the Wikipedia chart: https://en.wikipedia.org/wiki/List_of_WLAN_channels#5_GHz_(802.11a/h/n/ac/ax)

ehh i can run 160mhz on non dfs channel just fine , even with standard settings from scratch

 

[MDM]

ehh i can run 160mhz on non dfs channel just fine , even with standard settings from scratch

On 5GHz no you can not.. Only on 6GHz you can.

 

[robinjoo1]

On 5GHz no you can not.. Only on 6GHz you can, or the rare UNII-2-Extended...

 

[MDM]

View attachment 55772

That is DFS too (for 100MHZ of it); did you even look at the diagram..?
The Control channel in itself does not matter if it is in DFS or not, only the entire 160MHz range does!

 

[robinjoo1]

That is DFS too (for 100MHZ of it); did you even look at the diagram..?

sorry i didnt but why it says dfs state idle then will i still switch when radar is detected ?

 

[MDM]

sorry i didnt but why it says dfs state idle then will i still switch when radar is detected ?

Again look at the diagram, DFS channels are not all Radar labeled!
That is, its not the same radar systems (military radar, satellite communication, and weather radar...).

 

[Tech9]

If there's interference detected on DFS channels 52 to 64, and it's going to change the bandwidth to 80MHz anyway, there's no need for it to change the primary channel at all. It might as well stay on channel 36 and drop the bandwidth to 80MHz.

This is exactly the expected behavior with fixed control channel between 36-48. Why did it jump to 149-161 - no idea.

will i still switch when radar is detected ?

Yes, but the expected switch is control channel 40 (if you have it set manually) and 80MHz wide. 36-48 is non-DFS range.