Velleman CS6MX-I - Manual (Page 10)

Sensitivity, ground effect & discrimination
You will be able to get more performance out of your detector if you
understand the relationship between three aspects of detector operation -
sensitivity, ground effect and discrimination.
If you increase the power of a metal detector too much the ground itself is
detected and false signals make the detector difficult to use. The ‘motion’
electronic system of the CS6MX will ignore many ground effect signals
but some types of ground, notably waterlogged or containing salts or
mineralisation require the detector to operate on reduced sensitivity.
However, the discriminate control must be used with care because some
objects, which could be valuable, have similar electrical characteristics to
rubbish items as far as the detector can tell. Higher levels of discrimination
also have the effect of reducing the depth of detection. For these reasons it
is best to keep the discrimination setting as low as possible.
Depending on how the controls are set the CS6MX can be set to ignore signals
from certain types of metal targets. Iron targets are identified by a low pitch
tone, however you can adjust the volume level of this tone so it can be clearly
heard or totally inaudible. The three tone discrimination is futher enhanced
by the Discrimination control in conjunction with the Discrimination Volume
control.
The discrimination control is used to determine the detector’s response to
‘mid range’ targets such as foil, nickel and 9ct gold. with the control set to
minimum, (and the disc volume set to maximum) every target apart from iron
will give a high pitch tone. As the control is turned progressively clockwise,
the response from these metals will then become a mid pitch tone. It is then
possible to reduce the disc volume on these targets so that only targets above
discrimination point are identified. This can be used to ignore the effects of
coke contamination.
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