GM24k Searching
22 Garrett Metal Detectors
Field Use & Tuning Tips
(cont.)
Overload:
The
GM24k
will overload when the coil is over
a large object or extremely heavy iron minerali-
zation. Lowering the SENSITIVITY will usually
cure a mineralized area, but will not do much to
eliminate a real target. With a little practice you
will figure it out. If the overload seems every-
where it is probably mineralization and lowering
SENSITIVITY is essential.
Target ID:
The
GM24k
has three different target identifica-
tion systems. First and foremost is the audio re-
sponse. In the All-Metal (or ZIP) audio mode, the
detector sounds off with a scaled pitch and vol-
ume raise over targets. In Beep mode, the detec-
tor will give a high tone for mostly good targets
like gold, silver, brass, and aluminum, and a lower
tone for targets more likely to be iron junk. It also
displays a Target ID number, using a scale from
0-99. You might think of this as a “dig percentage”
meter, with higher numbers being more likely to
be a good target to dig. There is also a Target ID
Bar, which gives you a block in the Iron, Gold, or
Alloy ranges. Segments farther on the right of the
screen are more likely to represent good targets.
Even with all of this information presented by
the
GM24k
, it is generally a good practice to dig
everything in gold country. Very small gold nug-
gets can fool any discrimination system, especial-
ly where the gold is encased in host rock. Still, in
challenging areas like mining camps the Target ID
system can give you more information about tar-
gets—it’s up to you to dig it or leave it.
Misclassifying Iron:
The Target ID will consistently identify some
types of Iron and Steel objects as non-ferrous,
particularly flat thin steel such as a can lid, very
large pieces of iron, and small solid pieces of iron
like heavy washers. Because this is a gold detector,
it was essential to design it so that it would tend
to call doubtful targets “non-ferrous” or “possible
gold”. In this way, eliminating the possibility of
mistaking gold for iron.
Ground Scan mode tips:
Prospecting takes patience. With a metal detec-
tor, it requires even more. There are certain areas
where the gold is so fine that metal detecting is
not an efficient recovery technique. For these are-
as you can use the
GM24k
’s Ground Scan mode to
track mineral deposits.
This feature is excellent for dry washes, creek
beds, and old channels where you might want to
process the dirt using a sluice, dry washer, or even
just a simple gold pan.
Hold the Padlock button on your
GM24k
and the
screen will show you the ground phase (two digit
number) and strength (top Target ID bar). Find
an area likely to contain black sand (and therefore
more likely to have gold) and sweep the coil over
the stream bed normally. Wherever the concen-
tration of minerals are the strongest (Target ID
bar fullest), drop a marker.
As you continue down your path you will end up
mapping the pay streak with your markers, giving
you a lane to work with your recovery equipment.
The sensitivity control works in this mode as well.
If there is no ground present, the first Target ID
segment will flash
Frequency Shift:
If you find yourself detecting with others, or under-
neath power lines, you may encounter EMI (elec-
tro-magnetic interference). Turn your
GM24k
off
and hold the Iron Cancel button while powering it
back on. Select a different frequency, using the
and
buttons. Select the frequency with the least
interference. To beging hunting again, simply
press the crosshairs (pinpoint) button to exit the
settings selection. Your new frequency selection
will be retained when the GM24k is powered off.
