bf adjusts the frequency of the 10.24Mhz BFO
fd0,4,5,9. What do these control? Hmmm. Bingo! These are for fine tuning! The radio performs fine tuning by adjusting the voltage across a set of varicaps, which affects capacitance and hence the frequency of the oscillator. These must be the limit voltages for .00, .04, .05, .09
lo controls the local oscillator offset.