Howzit

Just need a little help understanding something

Using i hypothetical N band for an AP i set the frequency to say 5180. knowing also that the N band is going to use 40mhz

the question i'd like to ask, does this 40mhz sit 20mhz on each side of this chosen frequency or is it completely 40mhz above or below the chosen number

Thats correct 5180 is the center freq (or atleast should be!!)