Whites TDI SL Owner's Manual page 8

TDI SL
Owner's Manual
out other minor trash targets at the expense of eliminating
potentially good targets such as jewelry, but this method is very
limited in the range of trash targets that are rejected.
Furthermore, the ground balancing method used by TDI has
a side affect with target responses. Target conductivities below
the ground balance point produce a positive response for which
TDI assigns a high tone. These targets are generally low con-
ductive such as small nuggets, jewelry, and small iron. Target
conductivities above the ground balance point produce a nega-
tive response for which TDI assigns a low tone. These targets
are generally high conductive such as silver coins, relics, and
large iron.
Low-conductive target
No target
High-conductive target
Ground balance point
Differential Response
The Target Conductivity switch can be used to eliminate either
class of targets, or to accept them all. Care should be used with
this feature as it is not always obvious as to how a target might
respond. Testing with known targets is the best way to learn the
responses, both with delay settings and conductivity mode.
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