Page
3
SECTION
2
BOOMERANG™
COMPONENTS
ELECTRONICS
PACKAGE
The
NJD
‐
5's
circuitry
is
contained
in
the
electronics
package.
All
aspects
of
operation
are
controlled
here.
There
are
receptacles
for
the
antenna’s
coax
cables,
the
meter
cable,
and
headphones.
Controls
include
power
on/off,
headphone
volume,
and
trip
(threshold
for
the
target
detection
tone).
A
meter
for
battery
charge
level
is
located
next
to
the
on/off
switch.
It
will
indicate
battery
level
only
when
the
NJD
is
turned
on.
There
are
also
two
slide
switches.
One,
marked
“Normal/
Receiver
Only”
turns
the
NJD
‐
5
transmitter
on
and
off.
This
aids
in
determining
if
a
strong
interfering
signal
is
being
created
by
the
NJD
‐
5
interacting
with
some
sort
of
circuitry
in
the
area
being
examined
or
if
the
NJD
‐
5
is
detecting
another
transmitter
operating
on
1830
or
2745
MHz.
The
switch
marked
“Normal/2
nd
Only”
is
used
to
turn
off
the
3
rd
harmonic
receiver.
This
is
useful
when
a
return
needs
to
be
evaluated
in
depth.
The
audio
section
of
the
NJD
‐
5
switches
between
the
2
nd
and
3
rd
harmonic
receivers
at
a
rate
of
about
two
times
per
second.
Sometimes
there
is
clear
(or
at
least
perceptible)
audio
on
the
harmonic
returns
from
listening
devices.
By
listening
to
only
the
second
harmonic
return,
information
regarding
the
nature
of
the
detected
device
can
be
gathered.
The
battery
charger
jack
and
the
fuse
holder
are
located
on
the
back
panel.
The
NJD
‐
5
is
equipped
with
a
dial
attenuator
in
‐
line
with
the
transmitter
output
to
limit
the
strength
of
the
transmitted
signal.
The
attenuator
is
adjustable
in
3
dB
steps
from
0
to
30
dB.
Set
at
9
dB,
the
transmitter
will
put
out
approximately
62.5
milliWatts.
This
is
a
recommended
setting
for
most
uses.
Operation
at
higher
power
levels
increases
the
likelihood
of
detecting
electronic
devices
outside
the
area
being
searched.
