Technical description and operating manual ST 167 and ST167W5
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7.3 RECOMENDATIONS FOR ART SEARCH
It is expedient to make primal signal analysis before ART source detection with the aim of excluding benign
signals. Signs of benign signals are: modulation absence, tele and radio audio signals presence, different radio
conversations, which are clearly not related to the exаminee room.
All other signals, having signs of modulation presence, including «digital» ones, should be determined as
dangerous, even if there are no any connection between room and listened sounds.
In general, using of sound control, as Bugging devices identification method currently limited. Classic bugging
devices are designed with using of analog modulation methods (Frequency modulation in most cases) are listened
and identified, but with «digital» modulation correlation between sound background of room and listened signal
is missing.
Frequency band choosing (from 2 to 20MHz available) is done considering the minuteness of analysis. As
wider the range, then faster the analysis, but noise level will be higher (respectively detection ability of small
signals will be lower)
Information about ST167 ART detection abilities is shown on TABLE 7. It contains dependence from the
radio transmission device emitted power, located on a specific distance from ST167 and signal level on ST167
display. This data is for 1000MHz frequency. This table data is estimates and do not pretend on formal
measurements.
Distance, m
0.1mW
1
mW
10
mW
100
mW
1
-50
-40
-30
-20
5
-
-50
-45
-25
7
-
-60
-40
-30
10
-
-70
-60
-35
Frequency range selection is determined by information about DRT frequencies. Due to the features of
radio waves distribution and cost, most widespread DRT are working in frequencies of 100MHz-2GHz.
Frequency range values and band affect on total analysis time: in range of 25-6000MHz and frequency
tuning step of 2MHz it is about 13 sec, in 100-2000MHz – about 5 sec. With frequency tuning step of 20MHz –
less than 1 sec.
7.4 SMS/GPRS DETECTION
This mode is intended, in general, for trackers (devices, designed for vehicles tracking). These devices
receiving information about device location through GPS channel and sending it through GSM or GPRS channel.
SMS transfer is mostly done by trackers user.
For GPRS transfer characteristically data transfer with predetermined time intervals and showing of
vehicle location on a map (on a tracker manufacturers site).
Trackers detection is complicated by:
Shortness of being in radio broadcast of SMS.
Uncertainty of broadcast time. Depending on tracker model possible variants are from periodic data
transfer with fixed time period (easiest for detection) to data transfer on demand.
