Iron Reject - Minelab GPX5000 Instruction Manual

Iron Reject

72
GPX 5000 Range
Off (All Metal), 1–10
GPX 4800 Range Off (All Metal), 1–10
Factory Preset Off (All Metal)
The GPX Series are capable of rejecting many ferrous (iron)
targets while still detecting non-ferrous targets.
While detecting in littered sites, much of the shallow iron
rubbish may be ignored with a high probability that valuable
targets will not be missed.
When Iron Reject is turned off no iron targets will be rejected.
Therefore, all types of metals will produce a target response.
This is known as 'All Metal' and is the preferred setting for
most situations.
In All Metal the detector will give varying volume and pitch
signals. This information does not indicate the type of metal in
the object.
When a target has been located; select an appropriate Iron
Reject setting; switch Ground Balance to Fixed, and sweep
Tip: Pinpointing a target
over the target. The coil should be passed back and forth
prior to recovery is best over the target centre several times. Keep the sweep across
achieved with Iron the target at an even height and as close to the ground
Reject Off.
as possible.
Note: When a target has been
located the coil should be
passed back and forth over
the target centre several times.
Remember to set Ground
Balance to Fixed for this and
Threshold
keep the sweep across the
target at an even height and as Ferrous Target
close to the ground as possible.
Non-Ferrous Target
Target signals when detecting in All Metal.
Audio Signal
Audio Signal
Threshold
Ferrous Target
Non-Ferrous Target
Target signals when detecting in All Metal.
Discrimination is dependent on target signals being strong
enough for the GPX Series to determine if the target is ferrous
or non-ferrous. If the signal is weak the detector will give a
non-ferrous response until the signal becomes stronger, i.e.
due to a hole being dug and the coil getting closer to the
Tip: To improve
target. The Iron Reject function is designed this way to allow
discrimination accuracy
maximum accuracy, while limiting the chances of rejecting a
you should always test the
desirable target.
target from at least two
directions (90˚ from each In some areas, such as mining camps, old building sites
other) so that the detector
or a farmers' field, you may choose less cautious levels
'sees' the target from
of discrimination. This may be because the soil is of low
different profiles.
mineralisation or the targets are large non-ferrous relics
that will not resemble ferrous targets. You may also use less
caution in a goldfield that has high levels of rubbish that
would not be otherwise detectable. Iron Reject allows you
to increase the amount of discrimination while knowingly
accepting more risk.
When Iron Reject is activated the detector rejects ferrous
objects by blanking the normal target signal. You will notice
the Threshold tone goes silent as the coil passes across the
ferrous target.
Caution: Do not attempt
to discriminate by
Blanking Signal
raising and lowering
the coil on a deep or
partially dug target. An
accurate discrimination
Threshold Threshold
requires an even side-
to-side coil motion. It is
Ferrous Target
Ferrous Target
recommended to dig all
Non-Ferrous Target Non-Ferrous Target
targets that do not give an
obvious rejection.
Target signals using Iron Reject. Ferrous target blanked. Target signals using Iron Reject. Ferrous target blanked.
Blanking Signal
Audio Signal Audio Signal
73