Ground Balance Procedure For Tracking - Minelab GPX-4000 Quick Start Manual

40 Ground Balance Procedure
for Tracking
(For Ground Balance Type – General)
1 Find a clear area of ground without any targets.
2 Change the Ground Balance switch to Fixed.
Fixed
3 Whilst keeping the coil parallel to the ground, lower
and raise the coil between 25mm and 100mm
(1" and 4") over the ground. Try to lower the coil as
close to the ground as possible without touching it.
4 While moving the coil
Balance switch to Tracking and continue moving the
coil up and down until the audio has stabilised and
any ground noise has stopped.
Tracking
A persistent signal may indicate a target in the ground.
If this occurs, then move the coil to a new location and
repeat the procedure.
5 When there is no longer a change in the Threshold,
the detector is 'Ground Balanced', and you can
commence detecting.
Note: When changing the Ground Balance switch from
Fixed to Tracking, a very fast auto-Ground Balance is
initiated prior to returning to a normal Tracking speed.
This fast Ground Balance only lasts a short time, so it is
important to be moving the coil before attempting to
ground-balance.
(see note), change the Ground
100mm (4")
Ground Balance re-set in Tracking
Whilst sweeping the coil, you can test if you are still
in harmony with the ground by stopping, and raising
and lowering the coil – if the Threshold remains
stable then you are still Ground Balanced. If there is a
change in the Threshold, then you need to re-set the
Ground Balance setting.
While moving the coil, press and release the
Quick-Trak button. A short 'beep' will be heard
which lets you know that a 3 second fast auto-
Ground Balance is initiated prior to returning to
Tracking. Once the audio has stabilised, you can
continue searching.
If you find that the Ground Balance needs to be
re-set quite regularly, you can select a Faster
Tracking speed. (pg. 54)
As Tracking continually updates the Ground
Balance setting automatically, repeated passes
over a target may result in the detector balancing
to the target instead of the ground, diminishing
the target signal and increasing ground noise.
Therefore, it is important to use Fixed when
pinpointing or when investigating a potential faint
signal with repeated sweeps.
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