Set LWAPP AP to 802.11n Channel Width
When the 40-MHz channel bandwidth is used, channels can be combined only in pairs of
two. For example, of the available channels 36, 40, 44, 48, 52, 56, 60, and 64, only pairs of
36 & 40, 44 & 48, 52 & 56, and 60 & 64 are allowed to be combined. If the current channel
for the 802.11a radio is set to 40 and you want to set the channel bandwidth to 40 MHz with
the ABOVE option, the controller does not allow for this because it would break the pairing.
Only the BELOW option can be used. If you want to use the ABOVE option, then the
802.11a radio must be set to use channel 36.