Smart RF is switching of the 2.4Ghz radio because it belive there is to much RF in the 2.4Ghz band
following lines configure this feature
select-shutdown
select-shutdown cci-high-threshold -80
select-shutdown cci-low-threshold -100
select-shutdown frequency-limiter 10
select-shutdown frequency 60
to disable
no select-shutdown
I would state this is a very good feature,and i would not recommend disabling it