clearChannelNum

This controls the actual hardware frequency the radio transmits on.
Most users should never need to be exposed to this field/concept.
A channel number between 1 and NUM_CHANNELS (whatever the max is in the current region).
If ZERO then the rule is "use the old channel name hash based
algorithm to derive the channel number")
If using the hash algorithm the channel number will be: hash(channel_name) %
NUM_CHANNELS (Where num channels depends on the regulatory region).