FREQOFF gives the increment to the LO sum for the baseband channel in MHz. This will only be used if FREQREF is used. The LO sum for baseband channel i will be set to FREQREF(i) plus FREQOFF(i), and BBSYN will be set to the absolute value of the difference between the LO sum and FIRSTLO. Please see FREQREF for a discussion of required parameters.