9
Chapter 3 DFX
™
Quick
Start
Search Fundamentals
The loop/search coil must be in motion (sweep-
ing from side-to-side) for this instrument to
respond to metal. Practice a smooth sweep of the
loop from side-to-side keeping the loop close to the
ground throughout the swing. Each pass of the
loop should take approximately two seconds
from right to left, two seconds to return from left
to right.
Walk forward slowly. Take small steps no greater
than half normal strides. Make sure each pass of the
loop overlaps the last by at least half the length of
the loop. Do not lift the loop at the end of each
swing. Keep it close to the ground at all times.
To become comfortable with sweeping the loop
takes some practice. Try to loosen up and find a
comfortable grip on the handle. Premature fatigue
may result from gripping the handle too tightly,
improperly adjusted rod or elbow support, and
limited body movement. Hold the handle loosely.
Adjust the rod and elbow support for comfort and
keep the elbow strap loose. Use your arm, shoulder
and even your back a little to allow a smooth even
sweep of the loop.
Now that you're sweeping the loop smoothly over the
ground, you will notice that the detector starts making
sounds (beeps). Not all sounds are good targets;
some trash targets also make the detector beep.
As the loop is swept over the ground, ignore the
display and concentrate on the sounds the detector
makes.
As the loop is passed over metal that is likely trash,
the sound will be inconsistent. Trash targets typi-
cally produce a shorter, sputter-type sound, that is
often broken or double in nature. Place a steel-pop
bottlecap on the ground. Pass the loop over it
several times to become familiar with this sound at
different loop sweep speeds. Note that an aluminum
twist-off bottlecap cannot be used as it is a differ-
ent type of target. Also note that very old rusty
bottle caps may start reading as quarters due to the
elimination of the iron alloy through deterioration.
Once familiar with the sound typical bottle caps
produce, an operator may pass over such targets and
continue searching without consulting the display
information, saving more time for evaluating
possible good targets.
As the loop passes over metal that is likely a good
target, a more consistent and smooth sound will be
heard. A good target typically produces a longer,
more solid sound. Place a quarter on the ground and
sweep the loop over it several times to become
familiar with the sound of a good target.
Why Air/Ground Balance?
When the display prompts you to AIR BALANCE by
holding the loop at waist level and press ENTER. The
DFX
™
's circuits are being prepared for ground balanc-
ing by measuring temperature and other variables that
affect electronic circuits. The DFX
™
"beeps" and you
lower the search coil to the distance above the ground
that you will be searching. Press ENTER to have the
DFX
™
"cancel/track out" or GROUND BALANCE
the ground mineralization. The DFX
™
then automati-
cally "tracks out" the varying mineralization as you
continue to search.
