@dudload 

 

For your information.

 

If a wireless router intends to start using any of the DFS channels in the 5 GHz band, it has to perform a so-called "Channel Availability Check" (CAC) first, which is mandated by the law. 

During this check the router scans the DFS channels it intents to use for the presence of radar signals.

Under European regulations this check has to last for a period of at least 10 minutes on channels 120, 124, 128 (yes, really!) and for at least 60 seconds on all other DFS channels. Only if there was no radar signal detected during the CAC the router is allowed to start broadcasting its wireless signal on the designated channels.

 

Even if you were already using DFS channels, changing some of the settings related to the 5 GHz WiFi will trigger a new Channel Availability Check and you have to wait again for the 5 GHz wireless signal to return.

 

Furthermore, selecting (for example) Channel 100 and Channel Width 160 MHz will also trigger a 10 minutes long CAC, because with this setting the router will actually be using channels 100, 104, 108, 112, 116, 120, 124, 128.

 

thanks - i've still got the issue where it changes back to channel 36 and 80mhz. Unlikely to be near a radar station in central london (zone 1, not near city airport), so not sure what's wrong with this router. Seems to be an issue reported lots elsewhere, so probably time to junk it and get a better one

@dudload 

 

https://community.tp-link.com/en/home/forum/topic/209342