Minelab GPX-4500, Instruction Manual

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32 33
Note: Tuning should be
done initially with the
Coil switch in Double-D
or in Monoloop (M). If the
interference is still severe
after completing the tuning
operation change the Coil
switch to Cancel and then
re-tune the detector if
necessary.
Tune
Reducing Electrical Interference
To Perform an Automatic Tune:
1 Hold the detector at waist height, with the coil
vertical, and slowly rotate through a half-circle.
Make sure there are no large targets or obvious
electrical interference sources close by.
2 Face the direction of the most interference and
hold the coil steady.
If you have difficulty holding the detector very still
for 60 seconds, you can place the detector on the
ground with the coil vertical.
3 Press the Auto Tune button. Keep the detector
completely still during the automatic channel
scanning process.
A single beep indicates the beginning of the Auto
Tune. The detector will begin to scan each channel
for the least interference. This may take up to
60 seconds.
The detector will select the quietest operating
channel identified. The end of the Tuning process
will be indicated by three sharp ‘beeps’.
When tuning the detector in close proximity to other
detectors, each operator needs to take turns tuning.
Do not try to tune two detectors at the same time.
Any interference is made more obvious with a faster
Motion setting (pg. 66). Therefore, you can assist
the Auto Tune function in selecting the quietest
frequency band by selecting Fast Motion before
performing the Auto Tune process. When the process
is complete simply return the Motion speed to its
original setting.
The detector may be affected by electrical
interference from powerlines, radio transmitters
electrical equipment or other detectors operating
close by. This interference causes the Threshold to
become erratic.
So that the detector experiences the least
interference for the current environment the search
channel can be changed automatically by the Auto
Tune button on the control panel, or manually in the
Manual Tune
(pg. 63)
setting via the LCD menu.
Auto Tune instructs the detector to automatically
listen to every channel and select the quietest
position. Automatic tuning may take up to 60
seconds.
The Manual Tune setting, via the LCD menu, allows
you to manually select and listen to every channel
for the least interference.
The best channel to select will be the one where the
audio response to electromagnetic disturbances
(e.g. powerlines) is the lowest.
It is best to tune with the coil away from the
ground and as stationary as possible. This gives the
detector the best chance of sensing all surrounding
interference (not associated with the ground or
targets) too select the quietest channel.
Note: Interference in some locations can change
during the course of the day so you may need to re-
tune from time to time to maintain a stable Threshold
as you move around the area.
There is only one Tune setting. Any changes made
manually will override the Auto selection.
Auto Tune
Auto Tune
Tip: If you would like to
know what channel has
been chosen after an
automatic Tune, access
the Manual Tune screen
and check the number
displayed.
500mm (20")