5GHz band overlaps with some radar installation. Some channels are required to perform a mechanism called Dynamic Frequency Selection (DFS) to adjust the frequency to avoid colliding with radar signals. DFS can cause a slow down in the start up time and may disrupt normal usage intermittently.

To mitigate DFS events, you can pick channels that are not subjected to DFS scan. You can check out this page for information of DFS channels on different countries: https://en.wikipedia.org/wiki/List_of_WLAN_channels