INTRODUCTION
The PULSE 12 is a boat-towed pulse induction metal detector.
Though it was primarily designed to locate large metal objects, it will
detect small targets though not at great distances. Pulse detectors
have been around since the mid 1970's and have had a major
impact on the search and salvage business. Their major claim to
fame is that they are very sensitive and do not generally detect
minerals (extreme concentrations of iron ore may give a modest
reading). This lack to mineral detection is an answered prayer for
salt water divers who have to contend with heavy mineralized
deposits on the ocean floor which produce large false readings on
conventional detectors. Pulse detectors, with small and medium
size coils, ignore these mineral deposits and respond only to metal
targets (ferrous and non-ferrous metal). The Pulse 12, with its very
large coil, has a Sample Pulse Delay Knob which enables the
operator to "tune out" most minerals. Pulse detectors work well on
land and in fresh or salt water.
HOW PULSE DETECTORS WORK
Pulse detectors operate by transmitting a continuous stream of high
energy magnetic pulses (one hundred per second), from the Coil.
After each pulse is transmitted, the unit then "listens" using the Coil
as the receiving antenna.
Figure 1
When a transmitted pulse hits a metal object, a magnetic field is
induced in the object. This causes eddy currents to flow in the metal,
which in turn generates a second magnetic field. This field is picked
up by the Coil, amplified, and then displayed by the meter and heard
in the speaker/earphone.
1
PULSE
COIL
NOTE: The transmitted
pulse covers a much
larger area than shown
above.
EDDY CURRENTS
COIL
COIL
RECEIVE
target
ANALOG OUTPUT OPTION
The analog output option allows the Pulse 12 to be connected to an
external device such as a strip chart recorder or data logger. The
analog output consist of 3 channels (one for each towfish) who's
output is 0 to +4.00vdc. The voltage is a representation of the
detection signal strength.
The analog output uses 4 wires and is wired to a 5 pin DIN connector
on the Pulse 12 as Follows:
LORAN C / GPS WIRING
RS232 WIRING
ANALOG OUTPUT WIRING
FISH 1
FISH 2
FISH 3
AUDIO
POWER
JW FISHERS MFG
1953 County St
E. Taunton, MA 02718
pin 1
Not used
1
2
3
4
5
Enlarged front view of 5 pin
connector . Pin 5 not
used.(PIN END)
fish 1
red
fish 2
green
pin 2
white
fish 3
pin 3
ground
black
pin 4
Analog output (0-4vdc)
Not used
1
2
3
4
5
5 pin socket
in box
5 pin DIN
Connector
in Pulse 12
Control Box
12
1
2
3
( with 0 183 int er face )
LOR A N C/ G PS
Sign al
R etu r n ( shie ld )
R ed
Bla ck an d S hield
N o te: con nect
sh ield t o b lack w ire
a t b oth en ds
(+)
(-)
E nlar ge d f ro nt vie w
o f 3 pin con ne ctor
( PIN E N D)
5 p in D IN
C o nn ec to r
in P uls e 1 2
C o ntro l B ox
L or a n /G P S
5 p in so cket
in b ox
1
2
3
4
5
No t u sed
F
IS
H
1
F
I S
H
2
F
I S
H
3
A
U
D
I O
P
O
W
E
R
J
W
F
I S
H
E
R
S
M
F G
1 9
5
3
C
o
u
n t y
S
t
E
. T
a
u n
t o n
, M
A
0
2 7
1
8
F I S
H
1
F
I S
H
2
F
I S
H
3
A
U
D
I O
P
O
W
E
R
J W
F
I S
H
E
R
S
M
F
G
1 9
5
3 C
o
u
n t y
S
t
E
. T
a u
n
t o n
,
M
A
0 2
7
1 8
5 pin D IN
C onne ctor
in Pulse 12
C ontrol B ox
R S 232
Re d
B la ck a nd Shie ld
R S2 32
Inte rfa ce
9 pin "D"
fe male
connector
pin 2
pin 5
N ot used
5 pin socke t
in box
1
2
3
4
5
3
Enla rged front view
of 3 pin connector
(P IN EN D )
1
2
5
2
EN D V IEW
White
