WiGLE.net

A nice addition would be to filter on 2.4 or 5 GHz networks in Web Maps, this way I could determine which areas need to be scanned again for 5 GHz networks.

Don't know if the Wigle database can distinguish between 2.4 / 5 GHz networks but this would be a nice new option on Web Maps.

Here Here! Probably the way to do this is to include query by channel number, certainly channels 14 and below are not 5GHz.