Bug Detector
covering a 1 MHz to 8+ GHz bandwidth
Radio
frequency field strength tester with the ability to detect very weak signals
(down to ambient levels of radiation that exist around us. The ambient radiation
level is usually due to local FM and TV broadcasts.) This Bug Detector detects
signals spanning the microwave, UHF, VHF and high frequency spectrum, covering a
1 MHz to 8+ GHz bandwidth. This includes 5.8, 5.2, 4.5, 3.5, 2.4 and 1.2 GHz
covert cameras and bugs, 2.4, 1.8, and 0.9 GHz cell phones and wireless phones;
300-400 MHz walkie-talkies, car keys and garage door openers; 70-150 MHz FM
transmission; 49 MHz bugs and even 27 MHz citizen-band transmissions. Detection
at 2.4 GHz is so sensitive, it will detect an operating “sealed” microwave oven
at 12 meters away and pick-up 2.4 GHz transmitting bugs at 8 meters distance.
The unique feature of this unit is the ability to use
special antennas and band pass filters through a SMA coaxial input connector.
Depending upon the frequency and directionality of the externally connected
antenna, highly directional frequency-specific instrument which is ideal
for counter-surveillance detection and for aligning transmitter/receiver
antennas over far distances.
The 1.8 – 6.4 GHz Log-Periodic Antenna
available with the detector boosts the sensitivity by 3 times. It also
narrows the directional detection characteristics to a longer, thinner scan
pattern directed along the long axis of the antenna. With prior instrumentation
it was necessary to “sweep” a room by moving the detection device from 30 to 70
cm away from the walls, ceiling and floor in a raster scanning mode, similar to
the travel of an electron-beam in a television CRT. That is time consuming and
back-straining work! Using the unit with antenna, the covert device can be
initially detected from 8+ meters away. That is outside the room or at the door.
Then, from the door itself, the walls, ceiling and floor can be scanned by
pointing the directional antenna and hand-sweeping the room. Now we can “SWEEP
THE ROOM FROM THE DOOR”, detecting the direction of the covert transmitter from
a distance.
Once the direction of the covert device is
detected, we move closer to it while decreasing the gain using the sensitivity
controller, keeping the signal measurement within the limits of the meter scale.
When we are so close that the meter reading is constantly at the highest level,
we reset this system to a wider-dynamic-range by switching to the MID
or LOG detection mode. In the LOG mode it is possible to pinpoint the bug up to
a few cm away without overwhelming the instrument by the high signal level at
such close proximity. If the signal is too strong, use the SMA connector to
screw on an external attenuator in series between the antenna and the detector.
Use as many attenuators as necessary to control the signal level for accurate
detection. Now we can identify that tiny hole in the wall as the pinpoint
opening to a covert camera or microphone!
The frequency specificity and
directionality is controlled by the external antenna connected to its SMA input.
The 1.8-6.4 GHz LOG Periodic Antenna works well in this manner. Using a 50 cm
long 2.4 GHz Yagi antenna improves the sensitivity about 7-8 fold at 2.4 GHz and
narrows the detection width to about 5 degrees. The detector unit can
be directly connected to such antennas or connected using a flexible
cable.
Avoid measuring transmitted signals which are directly connected
to the SMA input. The signal levels of such devices can be large enough to
damage the sensitive receiver input of the unit.
Directional antennas
usually have increased sensitivity along their longer axis. Pointing the front
of the antenna towards the transmitting device gives the strongest pickup – but
there is also an enhanced pickup 180 degrees away from that direction to the
rear of the antenna. The differences between the front and rear sensitivities
are usually specified by the front to back ratio in dB. More directional
antennas, (usually longer in length), tend to have higher front to back ratios.
When specifying the direction of the signal source, be aware of the diminished
signal enhancement directed from the rear of the
antenna.
Extremely sensitive instrument which detects
signals that are coupled to it in any manner. In this way is more like a
wideband receiver with an antenna input. The proximity to a metal cabinet, desk,
or automobile can affect the reading. Also, the proximity of your hand or body
may increase the reading, acting as the antenna and coupling a stronger signal
to the input. It is even possible to reflect signals directed toward your body
and redirect them to the detector. Be aware that although an external antenna is
optimized to enhance reception within a particular band of frequencies, it is
also capable of detecting stronger signals from out-of-band
frequencies.
When initially using the unit, it is
often perplexing why detected signals appear so fickle. By moving closer to the
window, the signal strength increases (the walls of the room tend to shield the
outside signals). The walls of the room define a resonant cavity – the room
itself. Radio waves bounce off the walls, ceiling and floor to give enhanced
“hot” spots (where the signals converge) or “cold” spots which are devoid of
signals. Different frequencies have their own hot and cold spots. When
moving it just a few cm the detected signals may change dramatically
due to these intensified and rarefied signal regions.
Polarization effects may also be apparent , especially when an external antenna
is used. Polarization effects are noted when rotating the antenna from a
horizontal to a vertical plane. The change in signal strength gives an
indication of the polarization of the transmitting source. It is even possible
to note changes in signal intensity in outdoor wide-open spaces. Buildings,
trees, people, mountains, etc. all reflect signals that produce variations in
signal strength. It is important to consider these other factors when detecting
and locating weak covert signals. Experience with use will overcome many of the
hurdles.
Speeds up and simplifies the installation of
wireless devices – from security cameras to wireless computer networks. With
wireless installations verifies the signal strength of the transmitting device.
It identifies the hot and cold spots in the region. Hot and cold spots are
usually undesirable as transmitters or receiver sites. It measures the baseline
level of RF at these sites and detects any interfering signals (RFI) that may
occur. Besides detecting the RFI, also can identify its
source.
The directional antenna optimizes the radio
link between a wireless transmitter and receiver. It is also helpful in
selecting a hub site for solid communication with its multiple secondary WLAN
sites. Corporate security officers use it to identify potential hacker-sites
outside their facilities and to help shield and position wireless transmitters
to eliminate those hacker-sites.
This is instrumental in identifying radio frequency interference sources
from coronas and arcing insulators on utility poles. By using a directional
antenna on it an offending insulator can be located from the ground. This
enables utility personnel to quickly and easily identify the problem from a safe
distance (Even bolts of lightning are detected by this instrument).
SPECIFICATIONS
Very High sensitivity – with a
maximum sensitivity of 45 uV (~-75 dBm) at 2.4 GHz
1 MHz to 8 GHz usable frequency spectrum.
Manual/electronic switching between antenna
inputs.
2 internal, fixed antennas that do not
require any adjustments.
A switch-selected SMA
coaxial connector for external antenna inputs - 50 ohm impedance, DC
isolated.
An adjustable sensitivity control – (
20 dB variable attenuator.)
3 detection
modes:
a. Linear – displaying 12 dB of the weakest signals.- For
detecting weak signals.
b. LOG – displaying 60 dB of signal strengths.- For
pinpointing signal sources.
c. MID – intermediate sensitivity and dynamic
range.- For moderate signal readings.
2 Display
Modes – An Analog meter and colored LED’s (which are readable from a distance
and at nighttime).
A switch-enabled silent
vibrator - with vibrations modulated by the signal strength.
A
1.8 – 6.4 GHz Log Periodic Antenna
