Fisher Gold Bug 2 Operating Manual page 13

MODE AND MINERALIZATION SWITCH SELECTION
conditions will usually require the HIGH MINERALIZATION setting.
IRON DISCRIMINATION MODE
Don't search in the IRON DISC mode unless the area is heavily
littered with iron trash. This mode is better used by hunting in the
NORMAL or AUDIO BOOST modes and switching to the IRON DISC
mode only to identify a strong target response. Don't trust the
IRON DISC mode to correctly I.D. weak target sounds. Targets
already dug can also be checked for their gold content by using
the IRON DISC mode. Swing the object past the search coil, holding
it in your fingers or in a plastic scoop. If it is a "hot rock" or small
ferrous object, there will be no sound. Some iron objects chirp or
click. If it is nonferrous metal such as gold, your Gold Bug-2 will
give a solid "beep."
Unlike the AUDIO BOOST and NORMAL modes, the IRON DISC
mode is unaffected by the SENSITIVITY control and threshold
settings. Also, unlike the other modes, the IRON DISC mode
operates without an audible threshold hum.
AUDIO BOOST MODE
In this mode, weak signals are louder than in the NORMAL
mode, but maximum loudness of strong signals is the same. The
primary purpose of the AUDIO BOOST mode is to help you hear
weak signals when there is interfering noise from wind, mining
equipment, vehicles, etc. Also, if you prefer using the speaker
(most people use headphones), you may prefer the AUDIO
BOOST mode even in quiet conditions.
Hunting in the AUDIO BOOST mode is best when the area has
few trash items, hot rocks and low ground mineralization. In areas
with many false signals, the AUDIO BOOST mode will amplify them
as well as signals from gold nuggets. The AUDIO BOOST mode
can also be used to recheck a disappearing signal, or to check
a faint signal to see if it sounds like a hot rock in AUDIO BOOST.
NOTE: Some faint static and occasional chatter is
normal in this mode. If you are running your
sensitivity too high for ground conditions (heavy
mineralization, trash and or hot rocks) you may
experience a constant, loud chatter as you sweep.
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