Colin is right
Check if the wireless card do support the channel the 5ghz is in.
Most of the wireless card will support non DFS channels
Anyways i recently notice something interesting.. i thought that all the card at least will suppport non DFS channel buts that not true.
I found that a client had a USB wifi adapter that just supported channel 36,40,44, and 48... it didnt support other non dfs channel like 149 ,153,157,161 and 165....
They had a special configuration in which just the 5ghz was on and we noticed that those usb adapters were not able to see the AP, if they were in 5ghz upper channels like 149.
But they could see an ap on lower channels like 36.
It was interesting though..
Cheers
Carlos