[ARC5] Why BFO's

[Robert Eleazer]

I believe that the SC-608/628 receivers like the BC-683 had a BFO.  Given that they are FM, that makes little sense.  But it seems that the BFO (called an IF oscillator) was used during the tuning process for preset channels, and to aid in alignment.

So perhaps that was the reason for it's use in the BC-639. Or maybe for zero beating with the transmitter?  The very similar BC-624 does not seem to have a BFO.

Wayne