You should only contact us from a telephone outside of
the potentially compromised location! DO NOT call
from your office or home; use your cell telephone only
from a discreet location.
discussing "bugs", the most often thought that comes
to mind is of a miniature transmitter placed behind
a picture frame, in a potted plant, in a desk or
perhaps in a floor lamp. But, have you ever really
considered what a "bug" is, or how it operates? What
frequencies does it operate on?
A "bug", in most instances, is a transmitting
device. It consists generally of a microphone, audio
amplifier circuit, a radio frequency an circuit, an
antenna and a power supply. Size will depend on the
application, ranging from the size of a pack of
cigarettes to as small as a pencil eraser. Commonly,
most are about the size of a quarter which includes
As for the range in frequencies, the "bug" can be
built to operate anywhere from below the standard AM
broadcast radio band to above the commercial
microwave frequencies of 40 GHz. The biggest threat
is from those operating from approximately 70 MHz to
about 300 MHz, simply because it is easier to build
them for these frequencies.
Generally speaking, these frequencies use less power
to operate. The antennas are shorter, component
selection is less critical and better transmitting
range is realized.
One of the things most often asked is, "where is the
greatest threat when looking for a "bug." The
largest percentage of devices are found in the
"amateur spy band" of approximately 70 MHz to 130
MHz. Why? Simply because more devices are
constructed and available which work in these
It takes no sophistication and very little money to
construct these transmitters. Kits can be bought for
$30.00 and up and contain about $5.00 worth of
parts. They and can be constructed in as little time
as a couple of hours (taking time out for a coffee
break) and can transmit a signal in excess of a
mile. A little more sophisticated are those devices
in the 150 MHz to 300 MHz range, only because more
care must be taken in their construction, but they
are equally as effective.
Most signals encountered will be in clear text,
either AM or FM. Where we start running into
problems is when the intelligence on the signal is
"manipulated". This comes about by the various means
of modulating a signal, such as transmitting an AM
carrier with an FM sub-carrier, or an FM signal with
an AM sub-carrier.
Another step up the line is the pulse position or
pulse amplitude method of modulation. the top of the
line is generally considered to be "spread spectrum
signals" in which the signal is spread over a very
wide frequency range versus a very narrow frequency
range for other signals.
The "bugs" sensitivity and transmitting range will
be directly proportional to their size. The smaller
"bugs" will have a limited range. Eavesdroppers have
been known to employ relay transmitters. A relay
transmitter receives the weak signal from the target
area and automatically re-transmits the signal to a
more distant point.
A sophisticated approach to bugging is the remotely
controlled "bug". This type of "bug" is used to foil
detection and to conserve battery life.
If you have any indication that a "bug" has been
planted in your area of responsibility you should
contact a reputable countermeasure firm that has the
expertise and technical equipment to detect and
neutralize a technical attack.