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Detecting Basics
Detecting Tips and Techniques
Follow these hints and techniques to maximise your
success with the GPZ 7000 detector.
• Metallic targets will usually give a 'solid' sounding signal
when the coil is swept across the object from any
direction. A metallic target generally produces a short,
sharp and mostly symmetrical signal. Ground noises
usually give a broad uneven signal when the coil is
swept from different directions, and often may only give
a signal from one direction and no signal on the return
sweep.
• If you are not sure if the sound is ground noise or a
target signal you should always investigate. Scrape a
shallow hole about 30mm (1") deep over the suspected
target. Sweep the coil over the hole at the original
ground level. Do not dip the coil into the hole. If the
signal has decreased in volume or is less defined it is
probably ground noise. If the signal remains the same,
or becomes louder, it is likely a metallic target. If you
are still not sure make the hole deeper and repeat the
process.
• A 'halo effect' , which may be built up around a buried
metal object, makes the object appear to be larger to
the detector than it actually is. This will be reduced
once the target is disturbed from its position in the
ground (e.g. a small object, detected at a substantial
depth, may be more difficult to detect once disturbed
from the ground and lying in the loose dirt. If the object
is re-buried the 'halo effect' will not be present).
• Do not try to eliminate what might appear to be a faint,
isolated ground noise by using Quick-Trak over the
target; you may be 'balancing out' the target response
from a deeply buried metallic target. It is better to
Quick-Trak nearby the target, without going across it,
then checking again.
• Dig all target signals, even in previously detected areas.
The GPZ 7000 has superior ground balancing and depth
so it is possible to find new targets in well-worked areas
where other detectors have been unable to cope with
the high degree of mineralisation.
• In some mineralised soils a response may be received
from a concentration of orange/reddish dyke material
or clay. Remember, a metal target will get louder by
moving the coil even centimetres closer.
• Very sudden or large changes in the mineralisation of
an area may produce a signal from the detector. Usually
this signal is very broad and often only present in one
direction.
• If detecting areas of extremely variable mineralisation
detect along the ground contours rather than across
them. This will often reduce false signals from the rapid
change in mineralisation
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