About this app

ST171 is designed for detection of:
 Cellular jammers (blockers)
 GPS/GLONASS receiver jammers (blockers)
 Ultrasonic and electromagnetic jammers of sound recording devices, dictaphones etc.
This application requires the special hardware device ST171 as a receiving module (RM).

Additional features:
 Detection logging
 Environment snapshot at detection moment
 Location fixation at detection moment
 Base stations signals spectrogram indication in 900 and 1800MHz, sonic and ultrasonic ranges.

Software cellular jammer detectors and ST171 jammer detection comparison
Software cellular jammer detectors
Software cellular jammer detectors are based on hardware capabilities of Android or Apple device itself –
smartphone or tablet (hereinafter smartphone). For using of these it is enough just to download special application (like
«Jammer detector»).
Working principle of these detectors is based on smartphone connection with a base station. Actually, it
corresponds with base station signal level indication condition on smartphone display. Bigger the indication scale –
stronger the signal. When indicator is empty – no connection. This software can show only fact of lost connection with
a base station by vibration or indication on display.
Based on working principle some limitations of effective using of such kind of detectors exist:
 Cant detect all types of jammers
Modern smartphone uses 3 main frequency ranges: 2G, 3G and 4G. In each of them additional ranges exist. In
frequency resources distribution some differences exist depending on region, country. Cellular jammer detector
can’t cover all ranges. In this case smartphone with working jammer nearby will not have connection with a base
station and jammer will not be detected.
 Long detection time
Time between jammer turn-on (entering working zone) and loss of connection with a base station is sufficiently
large (from 1 to few minutes). In this way there is no possibility for jammer detection in moving cars and search of
jammer by smartphone movement is extremely difficult.
 Short detection range
Detection range is equal to jammer suppression zone. For portable models this zone can be about 1 meter.
ST171 jammer detector
 Working in all frequency ranges.
 Detection range is from 0.1 sec., what provides an opportunity of jammer detection in moving cars and search by
smartphone movement. Additionally, it makes expedient to use such built-in functions as photo when alarm and
location fixation.
 Long detection distance. Original algorithm provides jammer detection on distance which is few times bigger then
tis suppression zone.
 Alarm conditions combination ability by using of suppression channels analysis of GPS reeivers and frequencies,
which are nearby from base stations frequency range.
 2 working modes presence: «Office» and «Car» with own presets.
 Ability for «fine» tuning
 Detection of sonic, ultrasonic and radio emitting Dictaphone jammers.

App Permissions

Allows an application to record audio.
Allows access to the vibrator.
Allows applications to connect to paired bluetooth devices.
Allows applications to discover and pair bluetooth devices.
Allows an application to receive the ACTION_BOOT_COMPLETED that is broadcast after the system finishes booting.
Allows using PowerManager WakeLocks to keep processor from sleeping or screen from dimming.
Required to be able to access the camera device.
Allows an application to write to external storage.
Allows an app to access approximate location.
Allows an app to access precise location.
Allows applications to access information about networks.
Allows an application to read from external storage.