Originally Posted by Capn Nik
lucky me....i have just aquired a NEW Pearce-Simpson/Gladding Newport
radio set. It not only has the AM, FM, and VHF bands but also MB and LW bands....there is a knob marked AFC and one marked BFO that I have no idea what they are as well.
BFO is indeed beat frequency oscillator and has been correctly described.
AFC stands for Automatic Frequency Control. It's most likely only active on the FM band on your radio. Back in the olden days, the tuning of high frequencies wasn't very stable with temperature changes, so the AFC circuit was added. To use it, with the AFC turned off, tune in an FM station, then turn on the AFC. It acts similarly to an autopilot
as long as the tuning drift is not excessive. It won't hold the station if the radio tuning goes too far away from the proper setting.