Autotune Mode - Fisher Research Labs F70 User Manual

OPERATING MANUAL

Autotune Mode

The Autotune mode is more sensitive and offers better feel than the Discrimination mode, and
is used to find all metal objects present in the ground. The search coil must be in motion for
objects to be detected. This is a single filter search mode similar to the "fast autotune",
"SAT", or "P4" mode found in other detectors you might already be familiar with.
SENSITIVITY This controls the signal gain, and is
adjustable from 1 to 99. In the presence of electrical
interference, high ground mineralization, or variable ground
mineralization, operation will usually be too noisy (wobbly
and erratic sound) if the sensitivity is set too high. At
settings above 90, the internal circuit noise of the machine
will probably be audible. The sensitivity level setting is
largely a matter of personal preference. However, if you
cannot hear at least some noise, the smallest or deepest
objects will not be detected
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GUIDE TO METAL DETECTING
THRESHOLD
Adjustable from -9 to 9.
At 9, you will hear the loudest background sound.
At -9, you will have the lowest possible level of background
sound.
This is also referred to as audio threshold. For maximum
ability to hear the weakest signals, adjust this audio
threshold high enough so that it is barely audible while the
detector is in use in the field. To eliminate the weakest
signals, adjust the audio threshold level into the negative
region, which will allow the machine to run silently if the
Sensitivity is not set too high.
SPEED
There are two speed
selections, DEFAULT and
SLOW:
dE = default.
dE provides the best target
separation.
SL = slow.
SL provides more sensitivity to
deep targets. SL is more
likely to result in noisy
detector operation at high
sensitivity levels.