Bench Testing - Garrett Atx Owner's Manual

BENCH TESTING

You should conduct bench tests to become more familiar with the ATX's
audio signals and operation using different Modes, Discrimination settings,
Iron Check, etc� Suggested test items include:
Various size gold nuggets or gold rings
In the absence of gold nuggets, a U�S� nickel or small bronze coin are
good imitators of the response characteristics of a similar size
�
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nugget
Coins or relics that you expect to find in your search area
Various size iron targets for testing the Iron Check feature
The ideal position for bench testing with the ATX is illustrated below�
Extend the lower stem and lay the searchcoil back on top of the stem� This
allows you to keep one hand near the controls while still reaching the coil
with your test targets�
It is best to test the detector outdoors away from sources of electrical
interference (e�g� power lines, electrical equipment and appliances,
fluorescent lights, transmitters). Tests should be performed with the
searchcoil completely stationary and several feet away from any large
metallic object�
For bench testing, take the ATX outdoors, away from electrical interference and large metallic
Extend the first stem and lay the coil back as shown above�
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objects
Set up: Start with Factory Default settings (in Motion Mode) and run
Frequency Scan to obtain quiet operation� If not sufficiently quiet, move to
a different location away from sources of electrical interference�
Basic testing: Begin passing various metallic targets from side-to-side
across the bottom of the searchcoil� Pass the targets both near and far from
the coil to hear how Proportional Audio works (i�e� loud for strong signals,
faint for weak signals)�
Tone polarity test: Pass various poor conductors (i�e� small nuggets,
( small bronze coins, etc�) and good conductors (i�e� large nuggets,
silver coins, etc�) to hear the tone polarity� Poor conductors will produce a
High/Low tone and good conductors will produce a Low/High tone�
Discriminationtest:Afterconductingthetonepolaritytestabove,increase
Notice how the poor conductors become reduced and
disappear first from detection while the good conductors are less affected�
Test various size iron objects to see the effects of Discrimination levels�
Then return to a zero Discrimination setting (1st LED)�
Iron Check test: Press and hold the IRON CK button and wait for the
double beep before scanning targets� Continue to hold the IRON CK button
while quickly scanning your test targets back and forth across the coil�
Notice which iron targets produce the very low-tone growl/grunt sound
and at what distances� Notice that many iron targets will create a different
response when their orientation is changed� Since the ATX's Iron Check
function is conservative to ensure that small/weak good signals are not
misidentified as iron, small iron targets may not identify as iron�
Test both ferrous and non-ferrous targets at various depths to become
familiar with Iron Check's capabilities and limitations�
Sensitivity test: Increase and decrease Sensitivity to see how detection
depth and noise are affected� (e�g� higher Sensitivity increases depth and
possibly increases noise)�
Pinpoint test: Hold a target to the side away from the coil, then press
and hold PINPOINT and wait for the single beep� While continuing to hold
pass the target side-to-side and front-to-back in a crosshair
pattern and notice the peak response occurs over the center of the coil�
Non-Motion Mode test: Finally, switch to Non-Motion Mode and notice
the differences from Motion Mode� In Non-Motion Mode, targets will not
produce the audio echo and static detection is provided� This mode,
can be noisier than Motion Mode, and more frequent Retunes
may be required�
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nickels
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Discrimination
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PINPOINT
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however
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