I use an Apple Time Capsule, you can separate the 2.4ghz network and 5ghz into 2 separate networks on a time capsule that is how I know the 5ghz is working because it sees the 5ghz network this time round. instead of just the 2.4ghz
I have 2 networks mainly because I only want devices running 5ghz to access the 5ghz band and the rest just 2.4ghz.
fortuatly there aren't many 2.4ghz devices left on my network so I may kill off my 2.4ghz network completely and just have a 5ghz network.
network is a 802.11AC only network I disables all other options N and below because there is no need all my devices support AC.