8
8
1
1
7
7
DD COIL CHARACTERISTICS
A DD coil is superior to a concentric coil, but sometimes requires a
different sweep technique.
Advantages are
1
1
.
.
Better target separation
2
2
.
.
Superior performance in highly mineralized ground
3
3
.
.
Broader Sweep- cover more ground with each sweep
If you experience multiple responses on a shallow target, you can
raise the coil, or narrow the sweep over known targets to only
intersect the center section of the coil.
BOTTLE CAPS
The disadvantage of the DD coil is its propensity to
classify steel bottle caps as coins.
If you hear a high tone in DISC mode and believe
that it is a coin, make sure it is not a bottle cap using
the following method.
1
1
.
.
If a repeatable ID# around 68 to 72, then it
should be a dime or copper penny.
2
2
.
.
If not in the range of 68 to 72, then:
a
a
.
.
Sweep the back end of search coil over
the target. If tone changes from high to a
low tone, it is probably a bottle cap.
b
b
.
.
Sweep search coil fast
across target.
1
1
.
.
If tone and ID-value
drop, it is probably a
bottle cap.
2
2
.
.
If a bottle cap, the
faster you sweep, the
lower the tone.
SWEET SPOT
The “center” of the DD-Coil is elongated (elliptical) from top to
bottom of the coil. With some practice you will find where the center
of this ellipse lies on your coil. Use this center point as a reference in
pinpointing.
Sweep back end
of searchcoil over
suspected bottle cap.
(Low Tone = Bottle Cap)
T
T
h
h
e
e
o
o
p
p
e
e
r
r
a
a
t
t
i
i
n
n
g
g
c
c
o
o
n
n
t
t
r
r
o
o
l
l
s
s
a
a
r
r
e
e
a
a
s
s
f
f
o
o
l
l
l
l
o
o
w
w
s
s
:
:
SENSI AND –
These controls change the detector’s sensitivity;
higher settings enable detection of deeper
targets. At power-up, the detector is pre-set to
75% of maximum sensitivity. At minimum, the
sensitivity is 35% of maximum. With each press of
the + or – touch pads, the sensitivity level is
displayed on the bar graph on the left of the
display. Upon reaching the minimum or maximum
sensitivity setting, the detector will beep twice.
While higher levels of sensitivity enable detection of deeper targets,
operation at high levels of sensitivity make the detector m
m
o
o
r
r
e
e
s
s
u
u
s
s
c
c
e
e
p
p
t
t
i
i
b
b
l
l
e
e
t
t
o
o
e
e
l
l
e
e
c
c
t
t
r
r
o
o
m
m
a
a
g
g
n
n
e
e
t
t
i
i
c
c
i
i
n
n
t
t
e
e
r
r
f
f
e
e
r
r
e
e
n
n
c
c
e
e
.
.
Higher sensitivity settings can also lead
to false signals in difficult ground conditions. Use lower sensitivity settings
to suppress interference or false signals from soil minerals when necessary.
I
I
f
f
t
t
h
h
e
e
d
d
e
e
t
t
e
e
c
c
t
t
o
o
r
r
“
“
C
C
h
h
a
a
t
t
t
t
e
e
r
r
s
s
”
”
,
,
r
r
e
e
d
d
u
u
c
c
e
e
s
s
e
e
n
n
s
s
i
i
t
t
i
i
v
v
i
i
t
t
y
y
.
.
AUTO TUNE (All Metal)
P
P
r
r
e
e
s
s
s
s
t
t
h
h
i
i
s
s
p
p
a
a
d
d
a
a
n
n
d
d
“
“
A
A
L
L
L
L
M
M
E
E
T
T
A
A
L
L
”
”
a
a
p
p
p
p
e
e
a
a
r
r
s
s
o
o
n
n
t
t
h
h
e
e
d
d
i
i
s
s
p
p
l
l
a
a
y
y
This mode is a ground-balanced all-metals
motion search mode. This mode offers the
maximum amount of sensitivity under most
ground conditions. The search coil must be in
motion to detect metal. One monotone sound
is emitted. No discrimination or target
identification is possible in this mode.
Use the S
S
e
e
n
n
s
s
i
i
t
t
i
i
v
v
i
i
t
t
y
y
or T
T
h
h
r
r
e
e
s
s
h
h
o
o
l
l
d
d
controls to change the sensitivity or
background hum. Maximum sensitivity to buried metal objects is
achieved with a slightly audible background hum.
T
T
o
o
a
a
c
c
h
h
i
i
e
e
v
v
e
e
a
a
n
n
a
a
u
u
d
d
i
i
b
b
l
l
e
e
b
b
a
a
c
c
k
k
g
g
r
r
o
o
u
u
n
n
d
d
h
h
u
u
m
m
:
:
1
1
.
.
Press AUTO TUNE pad to enter this mode.
2
2
.
.
Press S
S
e
e
n
n
s
s
i
i
t
t
i
i
v
v
i
i
t
t
y
y
+
+
or
-
-
pads until you reach a desired setting.
This sensitivity setting may be the highest “quiet” setting, or you may
hear a faint background hum.
3
3
.
.
Press T
T
h
h
r
r
e
e
s
s
h
h
o
o
l
l
d
d
+
+
o
o
r
r
-
-
pad until you reach a comfortable volume level.
The Sensitivity control works like a course adjustment in this mode.
The Threshold control works like a fine adjustment in this mode.
The AUTO TUNE mode
must be ground-balanced
to eliminate interfering
signals from soil minerals. See the section on ground balancing for a
description of this procedure.
CONTROL PANEL
F4manual-SPREADS(24pg).qx 4/13/11 8:30 AM Page 8
