AOR AR8600 Operating Manual page 40

The distance in kHz which the AR8600 can 'pull' depends upon receive mode, IF bandwidth and signal
strength... the wider the filter and stronger the signal then the further AFC can pull.
Typically AFC will pull in the region of ± 5 kHz to ± 15 kHz, the maximum value for AFC is set to
± 25 kHz so that the receiver does not continually tune across the frequency spectrum looking for
'anything' to centre tune.
The AFC process usually takes a few seconds to 'settle down' after which time it is normal for the
frequency display last couple of digits to flicker up and down in frequency... this looks like 'frequency
drift' but fear not, the frequency tracking is under strict control! Typical accuracy of centre tuning is
around 1.5 kHz. If no signal is present and the squelch is open, the last two digits will randomly flicker
around. When the squelch closes in the absence of a signal, the last two digits will stop flickering but
may display a frequency which does not strictly adhere to the bandplan. If you toggle AFC off, the
frequency display will jump to the nearest increment for the frequency band (appropriate to the tuning
step selected).