VFO Abstraction
2021-04-04
Mike Black W9MDB

RX -- The default receive -- we always use RX=VFOA -- we do not support reverse split as of 2021-04-04
TX -- The default transmit -- based on mode could be VFOA, or if in split/satellite VFOB or Sub

Main_A 
    RIG_VFO_A
    RIG_VFO_MAIN
    RIG_VFO_MAIN_A
Main_B
    RIG_VFO_B
    RIG_VFO_SUB -- for single VFO rig or dual VFO not in satmode
    RIG_VFO_MAIN_B
Sub_A
    RIG_VFO_SUB -- for dual VFO when in satmode
    RIG_VFO_SUB_A
Sub_B
    RIG_VFO_SUB_B -- unknown use for this so far but has set/get functions

# Note the IC-910 introduced a 3rd VFO
Main_C
    RIG_VFO_C -- - unknown use for this so far but has set/get functions
    RIG_VFO_MAIN_C -- - unknown use for this so far but has set/get functions
Sub_C
    RIG_VFO_SUB_C -- unknown use for this so far but has set/get functions