Velleman CS4MX-I - Manual (Page 10)

Sensitivity, ground effect & discrimination
CIGARETTE
PACKET
5p COIN
RING
PULL
SCREW
CAP
NAIL
HORSESHOE
MILK
BOTTLE
TOP
IGNORE (NO SOUND) POSITIVE SIGNAL (SOUND)
1 10
Effect of discriminate control position
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 CS4MX 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.
The CS4MX can be set to ignore signals from certain categories of metal
target. Small iron objects in the ground are a problem on many farmland sites.
These signals can be ignored by setting the discriminate control to 2 or 3 on
the discriminate scale. As the control is turned clockwise the signals from more
types of metal likely to be worthless can be eliminated.
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.
10