[tkfu]

One brand new wifi gotcha I just learned about, specific to 5GHz wifi: in the EU, that frequency band is used by other things, including radar for air traffic control and emergency services aircraft. The solution we decided on for that was to mandate that all 5GHz wifi devices stop broadcasting for a period of 1-10 minutes whenever a "privileged user" demands it.

I discovered this only when I moved to a place that has a higher-than-usual incidence of helicopters flying by and my wifi would randomly disconnect. I eventually solved it by finding the channel within the 5GHz frequency band that was least used by privileged users in my area, and now I only have a drop about once a month. But it used to be 3 or 4 times a day.

[tpolzer]

Unless your 5 GHz spectrum is crowded by other WiFi, you really want to be on channel 36, because that way you do not have DFS at all, see the table on Wikipedia: https://en.wikipedia.org/wiki/List_of_WLAN_channels