Minelab SD2200V2 Instruction Manual page 23

Instruction Manual Page 11
5.2.10 Level Adjust Control
There is usually some overlap between signals from useful targets and
some types of iron junk. Because of this, the operator has to use the Level
Adjust knob to select the amount of discrimination between two extremes:
no useful target missed, but some iron getting through (anti-clockwise)
and unlikely any iron detected but some small non-ferrous targets possibly
missed (clockwise - see page 21)
The Level Adjust gives the operator the ability to select the sensitivity and
likelihood of a target being discriminated as ferrous. The same control
also affects how the detector recognises ground mineralisation as opposed
to metal targets, while operating in Tracking.
Turning the control anti-clockwise increases the strength of a signal required
for iron discrimination to be activated. Turning the control clockwise has
the opposite affect, but non-ferrous targets are more likely to be mistaken
for iron.
The Level Adjust control has exactly the same effect in both
Disc and Disc + ID positions. In the All Metal mode it effects only the
Tracking mode. Set fully clockwise there is little danger of the Tracking
cancelling out genuine targets, however some ground may also give a
false signal. With the Level Adjust control set fully anti-clockwise most
ground signals will be tracked effectively but some faint, weak target signals
may be missed.
Minelab recommends that it is usually best to dig out all targets and only
use the discriminator in areas where the unreasonable abundance of trash
makes the digging of everything impractical.
Note: Discrimination functions will work only on strong, positive signals.
Weak signals will give normal "all metal" type signals. The shape or profile
of the object may also influence the ID tone on occasion. Check by passing
the coil across the target several times and from a variety of directions.