Minelab SD2200V2 Instruction Manual page 18

Page 6 The Minelab SD2200v2
Ground Balance Procedure
Ground balance both channels at once by setting the Channel switch to
Both. Move the coil up and down between 20mm and 100mm above the
ground, and while moving the coil, set the Balance Mode switch from Fixed
to Tracking. The fast ground balance lasts for only five seconds after
switching to Tracking. Therefore, it is important to be moving the coil as
the switch is thrown.
Figure 5 – Setting Ground Balance
Keep moving the coil until all ground noise has stopped. A persistent signal
probably indicates a target in the ground. In this case, move the coil to a
new location and repeat the procedure.
When there is no longer a change in the threshold while the coil is being
raised and lowered, the detector is said to be "ground balanced".
Once the detector is ground balanced, you can then decide to detect in
either Tracking or Fixed mode. If the ground is mineralised or variable, use
Tracking. If the ground is very mild, use Fixed mode and switch back to
Tracking temporarily if the threshold becomes noisy. Do not test a target
by switching to Tracking when the coil is above it.
5.2.9 Iron Discrimination
Discrimination is the ability of a detector to distinguish between different
types of metal targets and to assist the operator in identifying a target.
Some goldfields are littered with "junk", that is, metal objects which are of
little value and are an annoyance to detector operators. The SD2200v2 is
capable of rejecting a number of iron objects while still detecting
non-ferrous metals. The ability of the SD2200v2 to discriminate ferrous
targets means that while working these goldfields, much of the iron junk
can be ignored with little fear of ignoring valuable targets.