CS-770 GB
4
Transmit Coil
Search area
Pick-up area
Receive coil
GROUND EFFECT
The signal of your detector will be affected by the type of terrain you are searching. Normally this
effect produces an increase or decrease in the audio signal when the search head is raised from the
ground. This effect can be controlled in two ways. If the search head is kept at a constant height the
effect of the ground will be constant. The second method should only be used when the effect is
severe. This method is to de-tune the machine so that it is less sensitive to the ground. However this
will have the effect of making the machine less sensitive to coins as well.
USE OF YOUR DETECTOR IN THE FIELD
Detecting
To test for the type of signal you will get, take a coin or metal object and with the detector set up on
a table tuned as previously described, move the metal object towards and across the search head.
You will note that the volume will increase quickly as the metal object passes across the search
head, with the loudest sound occurring when the search head is immediately centred over the metal
object. As the object passes beyond the search head the sound will quickly fade.
The metal detectors employ a Total Response search head which means that the object can be
detected across the full width, back to front, of the search head.
See Diagram 3
Detection Range
Detection ranges will vary depending on the size of the object, the length of time an object has been
buried in. The best ground conditions are dry well compacted soils then coins can be found at the
greatest depths if they have been buried for some time and the coin has interacted with the salts in
the ground, thereby appearing larger to the detector. The worst conditions for detecting are on
loosely compacted or freshly dug ground or when the object has only recently been buried. In these
conditions detection range will be reduced. 90% of all objects are found within 6" (20 cm) of the
surface. Adverse soil conditions can reduce depth of detection by more than half.
