Page
1
SECTION
1
BOOMERANG™
OVERVIEW
The
BOOMERANG™
utilizes
a
known
physical
principle
that
states
that
any
rectifying
junction
with
sufficient
length
of
conductor
attached
to
act
an
antenna
will
not
only
detect
a
radio
signal
and
rectify
it,
but
also
will
create
harmonics
of
that
signal.
A
harmonic
is
a
whole
number
multiple
of
the
original
signal.
Since
the
BOOMERANG™
transmits
on
a
frequency
of
915
MHz,
its
2
nd
harmonic
is
at
1830
MHz
(2
times
915)
and
its
3
rd
harmonic
is
at
2745
MHz
(3
times
915).
Over
the
years
methods
of
detecting
the
presence
or
location
of
objects
have
been
developed
that
use
a
radio
frequency
beam
to
indicate
the
presence
of
targets
that
contain
rectifying
junctions.
The
method
of
detection
involves
detecting
changes
made
to
the
radio
signal
by
the
rectifying
junction
target.
Rectifying
junctions
are
PN
type
semiconductors
and
the
change
that
they
make
is
to
multiply
the
frequency
of
the
signal
beamed
at
them.
Semiconductors
create
harmonics
or
whole
number
multiples.
Targets
are
often
designed
into
tuned
circuits
for
maximum
detection
efficiency.
Applications
have
included
devices
to
locate
skiers
trapped
in
avalanches
and
more
commonly
are
seen
in
electronic
article
surveillance
systems
to
deter
shoplifting.
Detectors
of
this
sort
consist
of
a
transmitter
and
a
receiver
that
is
tuned,
for
instance,
to
the
second
harmonic
of
the
transmitted
frequency.
When
the
detector’s
receiver
detects
a
signal
at
the
harmonic
frequency,
it
can
be
assumed
that
the
target
is
within
the
pattern
and
range
of
the
antenna.
The
BOOMERANG™
utilizes
this
same
harmonic
creation
and
detection
phenomena
to
locate
devices
containing
semiconductors:
transistors,
diodes
and
integrated
circuits
used
in
eavesdropping
devices
and
other
electronic
products.
These
semiconductors
do
not
have
to
be
operating
in
order
to
be
detected.
Target
detection
range
of
the
NJD
‐
5
is
a
function
of
several
things:
the
power
of
the
transmitter,
the
sensitivity
of
the
receiver
including
the
antenna
gain,
and
the
nature
or
design
of
the
devices
being
detected.
The
NJD
‐
5
has
a
transmitter
output
of
500
milliWatts.
Its
receiver
has
a
sensitivity
greater
than
‐
105dB,
meaning
that
it
can
detect
extremely
low
levels
of
second
and
third
harmonic
signals
picked
up
by
its
antenna
The
BOOMERANG™
NJD
‐
5
is
capable
of
detecting
certain
circuits
containing
semiconductors
for
a
distance
of
up
to
20
feet.
An
attenuator
is
built
into
the
NJD
‐
5
to
limit
the
detection
range
when
it
is
too
great.
