11
disappears
when
the
locator
is
held
higher
or
when
the
gain
is
decreased
is
likely
coming
from
a
smaller
target.
The
signal
from
a
rusty
bolt
or
other
small
item
(see
Figure
14)
is
much
weaker
than
the
signal
from
a
larger
target,
such
as
an
18
‐
inch
length
of
3/4
inch
rebar
which
can
be
located
at
depths
up
to
7
feet.
Figure
14:
Decreasing
gain
Eliminates
Unwanted
Signals
Strongly
Magnetized
Markers
A
strongly
magnetized
marker
that
is
at
or
near
the
surface
will
provide
a
weaker
indication
on
both
sides
of
the
marker,
and
that
could
be
mistaken
for
the
marker.
The
heavy
line
in
Figure
15
represents
the
increase
and
decrease
in
the
audio
and
bar
graph
indications
as
you
move
the
locator
over
a
marker.
Between
points
A
and
B,
the
signals
increase
slightly
and
then
decrease.
Just
beyond
B,
the
signals
increase
rapidly,
peak
directly
over
the
marker
and
then
decrease
at
point
C.
From
C
to
D,
the
signals
increase
and
decrease
again.
Therefore,
if
you
do
not
move
the
locator
completely
across
the
marker,
you
might
assume
that
the
weaker
indication
on
either
side
of
the
marker
is
its
location.
The
two
weaker
indications
occur
because
the
locator
is
extremely
sensitive
to
the
magnetic
field
components
that
are
parallel
to
its
long
axis.
At
points
B
and
C,
the
field
is
perpendicular
to
the
locator;
therefore,
no
significant
audio
or
bar
graph
indications
are
produced
at
these
points.
Figure
15:
Signal
Pattern
from
a
Strongly
Magnetized
Marker
Summary of Contents for GA-92 XTd
Page 20: ...20 SECTION X PARTS DIAGRAM ...