Minelab GPX-4000 Quick Start Manual page 25

44 Coil/Rx
Changing the Sensitivity and
Receive (Rx) Fields of the Coil
Coil /
Rx
Double D
M
Cancel
Double D
+
T
Transmit
Double D
Receive
Coil/Rx allows you to change the sensitivity and
search patterns of receive (Rx) fields of the coil.
The GP series or Commander Range of Double-D
coils can change characteristics to suit different
detecting conditions and targets.
Coils not specifically designed for the GPX-4000
may behave erratically or be ineffective in either
Monoloop (M) or Cancel.
It is very important that you always switch off the
detector before changing coils.
You will need to re-Ground Balance every time you
select a new position for the 'Coil' switch.
Double-D
This is the most suitable electromagnetic field for
areas of medium to very high mineralisation. It is
also excellent for pinpointing as the target response
is strongest from the centre of the coil.
The search pattern of this position is the
conventional blade or wedge shaped signal through
the centre of the coil.
+ + +
R T R R T R
Monoloop
Cancel
M
Minelab Monoloop coils
can be used on the
GPX-4000 with excellent
results. We recommend
their use in conjunction
with the Coil/Rx switch in
Monoloop (M).
Cancel
Salty Environments:
In highly saturated salt
conditions such as ocean
beaches or large inland salt
lakes, the use of Cancel may
– give better performance
than Salt. As a general
performance comparison,
R
Cancel will be more
sensitive, but Salt has a
greater depth potential on
larger targets.
Monoloop (M)
This setting may be used in most locations of low to
medium mineralisation. Monoloop is also suitable
for locating small nuggets with Soil/Timings switch
set to Sensitive.
Use of Monoloop will often increase the sensitivity
of the detector but may also be a little more
unstable in heavily mineralised ground. Pinpointing
is not centred in the middle of the coil, but to the left
side and may give a complex signal when the target
is very close to the coil, so it is recommended to use
the left edge of the coil to pinpoint shallow targets.
Cancel
This setting provides a receive field that is
particularly stable in areas of electrical interference.
This position is ideal for detecting close to
neighbourhoods or where the Tune function has
difficulty selecting a quiet operational channel
(e.g. near power lines, phone towers or under poor
atmospheric conditions).
Pinpoint in Cancel will be to the left side of centre
and signals may be complex if the target is close to
the coil. In Cancel, Sensitivity and depth are slightly
reduced.
Tip: You may be able to increase Gain if using Cancel.
(pg. 65)
The detector will not detect targets
if Cancel is used with a Monoloop coil.
45