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6.3 WIRE LINE SCANNING ANALYSER CHANNEL
Select suitable extensions, depending on the line, and connect them to the probes.
Plug the adapter into the socket, and connect the probes to the line. Check if the probes are in proper
contact with the line; two light-emitting diodes in the adapter of the scanning receiver will indicate the
following:
- if both LED’s are lit, the line carries AC power;
- if one LED is lit, the line carries DC power;
- if neither is lit and the contact is secure, the line is de-energised, or the voltage is below 3V.
The brightness of the LED’s depends on the voltage.
Upon activation in this mode, the device takes 2 seconds to estimate the average background signal and
automatically selects the threshold of action that will be shown briefly in the format “SQUELCH= -… dB”.
If this value exceeds –30dB, operation in this mode may be difficult due to strong interference or
noise at the connection spot. In this case it is recommended to connect the attenuator ST131.AWL.
When the threshold of action is selected, the device proceeds to scan the line. During the scanning
sound volume is set to minimum.
Any signal exceeding the threshold will terminate the scanning (the message ‘RUN’ will change to
‘STOP’), and the sound volume will be set to a pre-selected level.
Scanning can also be stopped at any time by manually pressing the "3" button.
After you have audio-monitored the suspect signal scanning can be resumed by pressing button "3".
In this channel it is reasonable to use the function “
SPECTRAL SUBTRACTION
” (pressing the
context button “
DIFF
”). It allows to see the signals that were absent before.
ADDITIONAL RECOMMENDATIONS
Check of availability of the STM in electrical network starting from the outlets. Their internal cavities
are the most probable location of the STM. All electric appliances and apparatus placed in the premises
under check must be switched off for reduction of the noise level.
ST034 must be connected to all outlets and power sockets in the premises because power supply of
the premises (as well as transfer of information from the premises) can be carried out from different
phases. After checking power lines you need to check the T-outlets, extension cords, and other energy-
consuming facilities by sequentially connecting them to the electrical network.
Checking of the wire lines of the security and fire alarm systems as well as the lines of unknown
purpose is similar to check of electrical network lines.
When checking telephone loops it is necessary to solve a task of revealing the fact of use of the line
for transfer of acoustic information from the premises by means of the linear high-frequency imposing.
Indication of the presence of the linear high-frequency imposing is availability of steady unmodulated
probing signal.
6.4 INFRARED RADIATION DETECTOR CHANNEL
Visually (reading the scale) and aurally, estimate the level of infrared radiation.
There are two key options of information leakage using IR radiation. One of these options is created
by application of the STM with transfer of the intercepted information in IR range. The other one is based
on irradiating the window glasses by directed rays of IR radiation source and receiving returned signal
modulated by acoustics of the premises.
Specificity of the IR STM is a need of provision of line of sight between IR transmitter and receiver.
Therefore, in the premises a path of transmitter radiation can go through window openings or from them
(a transmitter installed in window frame directly). Taking into consideration such peculiarities you should
begin search of dangerous signals from the windows of the premises then moving deep into the premises.
When doing so you should use a special support for searching STM installed in the window frames. Mount
IR sensor on the support directing input part of the sensor to the premises.
The sources of the noise in this channel are the following: solar radiation, electroluminescent lamps,
incandescent lamps connected to power mains with presence of high frequency parasitic components.
When checking exclude entry of direct sunbeams into the premises as much as possible and switch off
