20 21
9 Switch the detector to Disc mode.
10 Turn the Discriminate control to 1.
11 Sweep the coil across the objects, one at a time, and
observe the sounds.
Take note that as the coil is passed over the nail, the
threshold ‘hum’ momentarily disappears (blanks), and
then returns with a lower pitch. This indicates that a
ferrous target is located underneath the coil, but has
been rejected by you.
12 Whilst sweeping the coil across the objects, turn the
Discriminate control progressively clockwise until the
detector rejects the pull-tab.
Take note that as the coil is passed over the pull-tab, the
threshold ‘hum’ momentarily disappears (blanks), and
then returns with a higher pitch. This indicates that a
non-ferrous target is located underneath the coil, but
has been rejected by you.
‘Blanking’ (No Sound)
Threshold
Threshold
Target Response
Before attempting to recover targets, it is important
to understand how to interpret the audio signals of
the detector.
1 Gather a collection of different metal objects, e.g. a
nail, pull-tab, aluminium foil, various coins, gold and
silver jewellery.
2 Remove all jewellery from your hands and wrists.
3 Take the detector outdoors, away from known
electrical interference or metal objects. If you are
getting signals from a clear patch of ground, there
could be buried metal objects. Try finding another area.
4 Lay objects in a line, sufficiently spaced apart to allow
the coil to pass between them, as shown. (pg. 21)
5 Turn the detector on, using the Threshold control.
Turn the Threshold clockwise until it reaches a stable,
audible 'hum'.
6 Switch the detector into Pinpoint/All Metals mode.
7 Turn the Sensitivity control clockwise to 5. The
detector may produce signals with the coil
motionless. These may not be target signals, but
signals caused from the surrounding environment.
You can overcome these false signals by reducing the
Sensitivity. (Sensitivity, pg. 25)
8 Sweep the coil across the objects, one at a time,
and observe the sounds of the detector as it detects
each object.
The Excalibur II should 'beep' on every target. Large
targets or targets close to the ground surface emit a
louder signal.
A Detecting Exercise
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