66
67
Motion
Adjusting Sweep Speed
The speed at which you sweep the coil has an
effect on target response time and Ground Balance
adjustment. Matching your preferred coil sweep
speed with the corresponding Motion setting can
reduce noise and improve target signal responses.
Very Slow and Slow
When carefully detecting a small area a Slow Motion
setting will allow for maximum stability; ensuring
good depth and sensitivity to small targets. For
maximum performance a very slow and steady coil
sweep needs to be employed when using the slow
motion options. Very Slow Motion can be used in
combination with a higher Gain and Deep or Boost
Audio Type to achieve maximum performance.
Medium
This motion setting is ideal for general detecting
when normal 'slow & low’ techniques are being used.
Medium will improve sensitivity to small targets
while detecting with a moderate sweep speed.
Fast
Fast Motion is useful when using a fast sweep speed
to cover ground quickly. In these circumstances,
a quick sharp target response is used to alert the
operator to a target. Fast will allow you to cover
more ground in a shorter amount of time.
Note: The Motion speed also effects how susceptible
the detector is to external interference. Basically, the
slower the Motion speed the less interference you will
get; resulting in a smoother Threshold.
If you are using a Fast Motion and the Threshold is too
unstable you can either select Quiet Audio Type
(pg. 68) or reduce Rx Gain (pg. 67).
Range
Very Slow, Slow, Medium, Fast
Rx Gain
Adjusting the Sensitivity
of the Detector
The Rx Gain function allows the GPX-4500 to be
optimised for differing conditions; controlling the
sensitivity of the detector to its environment
and targets.
With a high Rx Gain setting the detector will pick
up smaller and deeper targets, but may respond to
unwanted noise and ground signals. A high Rx Gain
setting is recommended for mild soil conditions and
areas of low interference.
With a low Rx Gain setting the detector will pick
up less unwanted noise and ground signals, but
may miss deep targets. A lower Rx Gain setting is
preferable for variable, ‘noisy’ conditions or high
interference areas.
The Rx Gain control should be adjusted to suit the
soil conditions and the coil being used. For example,
if you have found some nuggets in an area and wish
to detect the same spot with a larger Monoloop coil
it may be necessary to reduce the Rx Gain setting.
Always ensure the detector is properly ground
balanced, and tuned, before making any changes to
the Rx Gain setting.
Tip: Try using a slower Motion setting (pg. 66) to allow
a higher Rx Gain setting.
When using the Coil/Rx switch in Cancel (pg. 44)
a higher Rx Gain setting may be possible.
Range
1–20
Note: Be prepared to reduce
the Rx Gain setting if the
background threshold is
erratic. A smooth threshold
is preferred, as a lot of noise
will drown out a soft signal.
Summary of Contents for GPX-4500
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