White’s Electronics Goldmaster GMT - Manual (Page 23)

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Chapter 5 GMT Searching
Pinpointing or "X" ing the target:
In most cases, pinpointing is easily performed by
merely "X-ing" or crisscrossing. The loudest part
of the target will be under the center of the coil, just
as with any detector. After the approximate loca-
tion 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.
Handful Of Dirt:
Some prefer to pass the handful of dirt across the
coil directly. Caution must be exercised if this is
done. The GMT 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 searchcoil. 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.
GAIN and VARIABLE SAT (Self Adjusting
Threshold) Speed:
The (-) and (+) Ground Balance pads compensate
for common ground minerals in the area. The V-
SAT control compensates for the consistency of
that ground mineralization. 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 V-
SAT feature and/or reduce the GAIN 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 GAIN if the detector will
not operate smoothly. This is a false sense of
security. Recognizing a true target is the most
important part of detecting. This is an example of
when less GAIN 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 V-SAT and GAIN which produces
the desired results in your area. Therefore, if you
have been operating your GMT at the full level of
GAIN (10) 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
GAIN toward the Initial Setting triangle of (7 to 8).
If this does not correct the problem, start adding
some SAT speed by turning the SAT control slowly
clockwise. If this does not correct the problem, go
back to the GAIN and reduce it a little more and
add a bit of SAT. As I mentioned earlier it is sort of
like seasoning a pot of soup. Some salt and some
pepper. Remember any drop in GAIN below (7-8)
will result in some loss of depth. Any increase in
SAT speed above the Initial Setting of (3-4) 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 pos-
sible. 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 miner-
alized ground and the curvy road is like heavy