Ground Balance/Audio Reset Button; Noise Cancel Button - Minelab F3 COMPACT Operation Manual

When detecting minimum metal mines or targets with low metal
signatures, the F3 COMPACT should not be used on a selection
lower than the default setting (Position 4). Where possible,
Free From Explosive targets should be buried at the required
detection depth. Sensitivity options (Positions 4 to 7) should
then be tested to determine the most suitable sensitivity to

3.1.3 Ground Balance/Audio Reset Button

Easily identifiable as the Green Button located on top of the Handle
Assembly, this dual action button carries out the following functions:
a. Ground Balance. A key feature of the F3 COMPACT is its ability
to detect metallic mines in all ground conditions. False alarms due
to mineralised (magnetic/lateritic) soils are automatically removed
through the Ground Balance procedure.
b. Audio Reset. On occasion, the Threshold Tone may become
louder than normal. Holding the coil stationary over a metallic
object or over mineralised ground for an extended period of time
may cause this. Also, if the detector is being used in the kneeling
position (shafts retracted), any movement of the coil relative to the
shaft may cause the Threshold Tone to increase. The Threshold
Tone can be returned to the normal volume level using the Audio
Reset procedure (refer to section 4.3.2).

3.1.4 Noise Cancel Button

Interference from electrical motors, lights, power lines and other
detectors can occasionally cause the Threshold Tone to vary in
pitch and volume. When this occurs, the ability of an operator to
distinguish targets may be degraded.
Using the Noise Cancel function, the operator can initiate an
automatic frequency scanning sequence, as a result the F3
COMPACT will select an operating frequency that minimises the
effects of interference.
F3 COMPACT Operations Manual
* WARNING *
ensure detection of the target.
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