Channels 12+ are perfectly valid for WiFi use in some jurisdictions. In fact, they're useful exactly because they mostly transmit outside the range of normal WiFi channels.
802.11n works perfectly fine with channels 1+5+9+13, letting the guard bands intersect. The 1/6/11 set common to the USA leaves plenty of guard space to prevent overlaps, but wastes bandwidth in jurisdictions where channel 12 and 13 are disallowed.
802.11n works perfectly fine with channels 1+5+9+13, letting the guard bands intersect. The 1/6/11 set common to the USA leaves plenty of guard space to prevent overlaps, but wastes bandwidth in jurisdictions where channel 12 and 13 are disallowed.