front controls
– continued
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4 controls and operation
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page 36
GP 3500
After completing the Auto-tune, pick the detector up and with the coil rotated flat, into the
search position, listen to see if it is stable. If a slight interference is still present, you can use
the manual control to fine tune the selected band.
Manual Control
Manual tuning can now be used by the operator to fine tune after the Auto tuning is
completed. In areas where there is no interference being experienced, the Manual control
can be used to select a personal search band.
After completing the auto-tune, to fine tune the band, start turning the manual control quite
slowly in one direction, listening if the threshold becomes more stable or flaky. If this direction
does not improve it, try the opposite direction. It is quite important that you turn the control
slowly to make very fine adjustments.
If the interference persists after tuning, consider using the Coil switch set to Cancel position
and retune again
Hint:
If detecting in a benign area of no interference, you may find that you can select a band
at one end of the scale or the other. Frequency bands in the counter-clockwise ‘start’ direction
are lower frequency bands and higher frequency bands are toward the clockwise end. Turn
the control in the desired direction until the one beep or two beep signal is heard. Then using
slow turns in the reverse direction find a band which is stable. This will not make much
difference but low frequency bands can give a little more depth to larger targets and high
frequency bands can give slightly more sensitivity to smaller targets close to the surface.
Important: The manual control will signal when you have moved to the end of the
range of frequency bands. When you arrive at the counter clockwise starting point
you will hear a single beep to denote that this is the start, moving clockwise to the
other end, you will hear two beeps to denote that it is the finish.
Note – When turning the control rapidly to move to the desired
end you want, you will notice noise caused by the rapid
movement through the frequencies. This is normal and
will not be present when the control is turned slowly.
There are 14 turns of the control from start to finish.
Hints and techniques for better detecting and happy prospecting that will help you to
utilise the power of your GP 3500
Some user tips:
•
Always ensure that the battery is at full charge so that your detector is working at
optimum performance. A worthwhile recommendation is to own a spare battery which
you can swap half-way through the day thus making sure that you are always working
with full power.
•
The battery should be worn in the backpack harness supplied. This places the battery
at the furthest practical distance from the coil.
•
Ensure that you do not set the shaft length too short. If the coil is too close to your
body it might detect your pick, the battery or any other metal which you are carrying.
Steel toe boots can obviously cause a problem with false signals. If false signals are
occurring as you sweep the coil, check that they are not produced by any metal that you
are carrying. Move the coil closer, and then further away from your body, in order to
check if the signals are coming from items such as your pick, boots or battery. If they are,
you must increase the distance between the coil and these items.
•
Take the time to experiment with the different settings, to fully understand how to get the
most out of your detector in different locations.
Motion detection
The GP 3500 is a 'motion' detector. Therefore the detector must be moving
over a target to detect it.
Parallel Sweeping Procedure
•
The coil should be swept over the ground in
a side-to-side sweeping motion.
•
While sweeping the coil, it is important to
keep it parallel to, and at the same height
from, the ground at all times. Lightly skidding
the coil across the ground can sometimes
help in this, depending on mineralization.
•
Do not raise the coil at the ends of each
sweep as this will reduce the detection depth
and may cause false signals.
Figure 5.1
- Parallel Sweeping
GP 3500
www.minelab.com
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detecting techniques
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5 detecting
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