GENERAL HINTS
Beach Mode
On a wet salt beach it is best to reduce the SENSITIVITY to mid range and operate in a
Discrimination Mode all the time (i.e. G
D1
or G
D2
then press the DISCRIMINATE push button
and release).This is because the salt water makes the ground conductive, and to Ground Exclude
in these conditions the detector needs to be set at a point where iron is rejected. This is a useful
coincidence because it means that Ground Exclusion and Discrimination against iron are possible
at the same setting on wet sand with the CS1220XD.
The Ground Exclude setting for beaches will vary significantly and in practice it is possible to
reject silver paper and ground exclude on a severe beach. G
D1
is the recommended mode setting
and Discriminate level can be adjusted to suit the particular conditions.
It is essential when operating on a beach that the Search head is kept at a constant height above
the surface. It may also be necessary to reduce the SENSITIVITY further because of variation in
the salt content over the area searched.
Lower the search head to the ground. Keep it at a steady height above the ground and ensure the
Tuning Level is set correctly by operating the RETUNE button on the Meter Console and then
release it.
If however, the detector is being operated in the Discriminate Mode on an inland site, it will be
necessary to balance the sensitivity level to reduce the ground effect. In practice this means
setting it to the highest level possible, which of course will depend on the degree of
mineralisation, and how capable the operator is at keeping the search head level with the ground.
A sacrifice in sensitivity level will drastically reduce the ground effect, but will not reduce the
depth penetration to the same degree. For example, by reducing the sensitivity level from full to
midway, ground effect will be reduced by 80%, but depth penetration will only be reduced by
about 20%.
Discriminating
When used in the Ground Mode the CS1220XD will detect all metals and will not discriminate.
However, in the Meter Disc and Meter Audio Disc Modes the CS1220XD has been programmed
to operate at a fixed discriminate setting.
It is recommended that all objects that are not rejected should be recovered, i.e. if the meter
needle does not dip or the audio pitch is inconclusive, then find the object.
Iron, unlike a coin, occurs in a multitude of shapes and sizes and as a result it is possible that
large pieces of iron may give a positive reading. Iron in the shape of nails or pieces of wire also
may be present on the surface of a site. In this case anomalies in discrimination may occur.
Anomalies or confusing signals can occur in the first few inches away from the search head, and
are typically characterised by a double signal from the same object, usually iron, which often
ranges from a strong positive to a strong negative signal. To overcome these problems simply
raise the search head, retuning if necessary, and rescan until a clear signal of rejection or
acceptance is obtained.
13
