Applicable to AU/BU with HW revision B and lower
(for units with HW revision C and higher replaced by
brzaccVLAUDefinedFrequencyNew to support a resolution of 0.5 MHz).
For 5.8GHz products with SW version below 2.0 this is the frequency
in MHz of the AU/BU after the next reset.
For units with SW version 2.0 and up this is the frequency in MHz
to use when the DFS Option is disabled.
For 5.8GHz products with SW version below 2.0 the range is
5740 to 5830 MHz using 10MHz resolution.
For units with SW version 2.0 and up the range is as defined
in the selected Sub Band.