Forcing on 40MHz in nv2

Hi

When we using MIMO(nv2) and 802.11n-Only and selecting 20/40 MHZ Channel bandwidth, We do not able to forceing the Bitrate on 40MHz only, when the link established on the Registration tab the bitrate change between 20&40MHz .
Is a way to forcing the Channel bandwidth on 40MHz ?
Thanks

G00DLUCK

Select datarates manually. Select only those which need 40mhz

select rate-selection=advanced and leave rates unchanged, it is not safe to turn off some rates as you can encounter problems to connect to the AP with rates changed. RotuerOS will choose one rate that is most suitable for transmit/receive power at the current situation. In 5.11 default value for wireless interface is advanced instead of legacy.