Discriminate Rejecting Unwanted Targets - Minelab Excalibur II Instruction Manual

Discriminate
28
Rejecting Unwanted Targets
In Disc mode, the Discriminate control becomes active.
Discriminate allows you to reject or 'ignore' certain
target signals while detecting.
Low setting
With the Discriminate control set to 1, the Excalibur II will
reject or 'blank' the threshold on ferrous metal objects
while still accepting non-ferrous metal objects.
High Setting
As you turn the Discriminate control further clockwise,
objects with greater conductivity will be ignored, while
objects of higher conductivity are still accepted.
Low Setting
Nail Aluminium Foil
Ferrous
Nail Aluminium Foil
Ferrous
9K Gold Rings Pull-tabs 18K Gold Rings, Brass,
Some Coins Copper, Lead, Some Coins
Non-ferrous
High Setting
9K Gold Rings Pull-tabs 18K Gold Rings, Brass,
Some Coins Copper, Lead, Some Coins
Non-ferrous
You are also able to determine whether a rejected target
was ferrous or non-ferrous by the pitch of the returning
threshold after blanking. A rejected ferrous object will
cause the returning threshold pitch to be a low tone,
while a rejected non-ferrous object will cause the
returning threshold pitch to be higher.
The Discriminate setting must be relative to the types of
objects that you wish to hunt for and the amount of trash
that you are prepared to detect. For example, if you are
hunting for fine white gold rings and set the Discriminate
control to position 4, you may also find some types of
aluminium foil. If you do not want to dig old bottle caps
but do want to dig brass buttons and copper coins, the
Discriminate control should be set higher (approximately
at number 13). Note however, that by doing this, most
fine white gold rings, foil, and some yellow gold rings
will also be ignored.
The two objects treasure hunters most commonly wish
to ignore are aluminium foil and pull-tabs. These objects
both cover a significant range on the Discriminate
control. Setting the Discriminate control 'high' to
eliminate all unwanted items will cause you to ignore
a large range of valuable items. We recommend that
you only discriminate the most common trash items,
accepting the occasional unwanted target.
As pull-tabs are made from various metallic alloys, their
conductivity can vary. Discriminate control positions for
pull-tabs may range between 11 and 15.
If the Excalibur II produces a high-pitched rapidly pulsing sound while
in Disc mode, the detector is being overloaded by a large piece of metal
close to the coil. Raise the coil slightly above the ground and pass it
over the area again to check the target. By lifting the coil away from the
ground, the Excalibur II is able to detect the object accurately.
29
Blanking
Blanking is the silencing
of the threshold when
the coil is passed over a
rejected target. Blanking
is a useful way of
distinguishing between
wanted and unwanted
targets.