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Chapter 5 MXT Controls
Threshold Control
The THRESHOLD control sets the loudness of the
background "hum" or edge of sound. This back-
ground "hum" should normally be maintained
during searching. In order to hear the tiniest and
deepest targets the THRESHOLD "hum" should be
set at the faintest audible level. It can be slightly
scratchy, chatter or static like but it must be con-
stant so as to not miss that small or deep targets. At
this point, we can't recommend too highly the
advantage of using HEADPHONES. With HEAD-
PHONES you can lower THRESHOLD "hum"
levels, you will hear the faintest of target signals
while cancelling out environmental background
noise and improving concentration.
Threshold Adjustment
The MXT has an improved microprocessor driven
THRESHOLD control that is adjusted with a single
turn. It does not, therefore, require a 10 turn pot for
precise adjustment. Digital software provides much
higher resolution, thus you can set the "hum" faster
and more accurately. Set the knob all the way to
the left or counterclockwise and then rotate it
clockwise until the faintest audible level of "hum"
is attained (edge of sound). If the "hum" disappears
for any reason (other than bumping the control) you
may be either swinging the coil too fast or your
GAIN control is set too high, or in the prospecting
MODE you may need to increase the speed of SAT.
Silent Search
With microprocessor driven THRESHOLD controls
arguably skillful operators can "cheat the system"
and use silent search with high performance results.
Once the threshold is found, edge of sound, setting
the Threshold control slightly counterclockwise
achieves silent search where no threshold hum is
heard during searching. By further optimizing Gain
to radical levels, much of that resulting noise can be
hidden under the Threshold and thus good field
results. Best reserved for more experienced opera-
tors, a balancing act between higher Gain V.S. a
stronger response required to surpass the threshold
setting, must be achieved and understood.
THRESHOLD CONTROL
“HUM”
Chapter 5 MXT Controls
