RADAR was detected on channel [Wi-Fi channel]; channel switched automatically because of higher-privileged user.

This is an event message from the "Wireless" area.

In accordance with the European rules for using Wi-Fi in the 5-GHz frequency range, the FRITZ!Box checks whether the 5-GHz Wi-Fi channel it uses is also used by a higher priority radar source, like, for instance, weather or flight radar. If so, the FRITZ!Box automatically switches channels (Dynamic Frequency Selection, DFS).

The status message informs you that a radar device, and thus a higher priority user, was detected on the specified Wi-Fi channel. As a consequence the FRITZ!Box set a different channel for the 5-GHz Wi-Fi network.

You can prevent channel changes forced by DFS by selecting in the FRITZ!Box a channel for the 5-GHz frequency band that does not use DFS (channels 36, 40, 44, 48).