Detecting Basics
In order to find targets,
detecting requires the coil
to be swept across the
ground.
Targets
Buried metal objects are referred to as targets. Targets are
comprised of both ferrous and non-ferrous metals.
Threshold (Background sound)
This is the background sound produced by the detector.
When a target is detected, the Threshold changes in volume
(and pitch in Disc mode). Listen to the Threshold carefully.
Concentration is an important part of detecting. A very
deep or small target may only give a minor change to the
Threshold. (pg. 22)
Target Response (Metal Object Response)
This is the term given to the change in the volume (and pitch
in Disc mode) of the Threshold when a target is detected
and not discriminated (rejected).
Electrical Interference
The detector may also produce sounds when the coil is
not over the ground. These signals are caused by nearby
electromagnetic sources such as power lines and phone
towers. (pg. 19)
Ground Noise
The detector may also produce various random signals
caused by different minerals in the ground, sometimes
referred to as false signals. (pg. 19)
Discrimination
Discrimination is the ability of a metal detector to identify
the user’s desired target (e.g. jewellery) and eliminate signals
from undesirable material (e.g. nails). The discriminate
control allows you reject or 'ignore' certain targets. (pg. 28)
Blanking
When sweeping over a rejected target, the Threshold
‘blanks’ (becomes silent) indicating that a target is located
underneath the coil, but has been rejected by you. Blanking
is a useful way of distinguishing between desired and
undesired targets. (pg. 29)
Common Terms
When in Disc mode, the Excalibur II is a ‘motion’ detector.
This means it must be moving over a target to detect it.
When in Pinpoint mode, the Excalibur II does not need
to be moving over a target to detect it. It will still give a
response when held motionless above a target.
The Excalibur II will perform at its best when the coil is
kept close and parallel to the ground, beach, river/sea
bed at all times. This will increase detection depth,
response to small objects and help prevent false signals.
Practise sweeping the coil over the ground in a side-to-
side motion, while walking forward slowly. At the end
of each sweep slightly overlap the previous sweep to
ensure full ground coverage. An average sweep speed
is four seconds from left to right to left. If you sweep too
fast your discrimination accuracy will suffer and you may
miss deep targets.
A variation in coil height at the end of each swing may
cause confusing sounds and reduce detection depth, so
an even, flat sweep is desirable.
