Chapter 5 GMT Searching
Pinpointing or “X” ing the target:
In most cases, pinpointing is easily performed
by merely “X-ing” or criss-crossing. You can
also use the new non-motion pinpoint mode on
the GM24k. The loudest part of the target will
be under the center of the coil, just as with any
detector. After the approximate location of the
target is determined, take a handful of soil and
check the hole again. Continue this process
until the target is no longer in the hole, but in the
hand.
Try putting the handful of soil in a plastic
container (pan, tray, cup, or scoop). Passing
the container over the coil will determine if the
target is really in it. If so, a series of separations
will quickly expose the nugget. This is called
“the 50-50” process. You take half the dirt out of
the scoop, and pass it over the coil. If the ma-
chine beeps, it’s in the scoop. Dump the empty
dirt and repeat until you have the nugget in hand.
Handful Of Dirt:
Some prefer to pass the handful of dirt across
the coil directly. Caution must be exercised if
this is done. The GM24k is sensitive enough to
pick up the salt in your hand and respond with a
signal. Try this with nothing in your hand and
you will see how close you can come to the coil
using this method. One way around this salt
sensitivity is to pinch the soil in small amounts
and wave only the fingers over the search-coil.
You will find the way best suited to your needs.
The condition of the soil - dry, wet, fine, coarse,
etc. - will have a lot to do with the best method
for you.
SENSITIVITY and VARIABLE SAT (Self
Adjusting Threshold) Speed:
XGB compensates for common ground minerals
in the area. The V-SAT control compensates for
the consistency of that ground mineralization
(accessed by holding the Music Note button).
The greater the degree of inconsistencies, the
more SAT is needed to quiet ground noise. If the
THRESHOLD becomes too erratic or noisy, it
might be necessary to use the SAT feature and/or
reduce the SENSITIVITY control. This noisy
behavior will make it difficult to recognize a true
target (possible nugget) from pieces of mineral,
commonly referred to as “hot rocks.”
It is not wise to keep a high level of SENSITIV-
ITY if the detector will not operate smoothly.
This is a false sense of security. Recognizing a
true target is the most important part of detect-
ing. This is an example of when less SENSI-
TIVITY will produce more nuggets. You must
be the best judge of just how much noise you
can tolerate and still identify nuggets, as well
as the combination of SAT and SENSITIVITY
which produces the desired results in your area.
Therefore, if you have been operating your G24k
at full sensitivity and you determine that this is
too high because either the threshold is erratic
or the detector is giving false signals; always
begin by reducing the sensitivity to a more stable
range. If this does not correct the problem, start
adding some SAT speed by holding the Music
Note button and using the up arrow. If this does
not correct the problem, go back to the SENSI-
TIVITY and reduce it a little more.
It is sort of like seasoning a pot of soup. Some
salt and some pepper. Remember any drop in
SENSITIVITY below (7-8) will result in some
loss of depth. Any increase in SAT speed above
the default setting of 2 will also reduce overall
depth. However, every ground condition has its
optimum setting.
Overall depth is not the ultimate goal. Finding
nuggets is! Unless your threshold is constant
and as smooth as possible, and free from false
targets which confuse the picture, you will never
be able to tell the ground from the gold. We like
to use the analogy of driving on a straight road
versus a curvy road. The object is to get from
point A to point B. 65 mph might get you there
on a straight road, but you will have to slow to
35 mph if the road is curvy, or you will end up
off the road. The straight road is like low min-
eralized ground and the curvy road is like heavy
mineralization. High SENSITIVITY and slower
SAT will not get you the gold in heavy mineral-
ization.
21
Summary of Contents for GM24k
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