ST CAYMAN 401 User manual

PORTABLE
NONLINEAR JUNCTION DETECTOR
ST 401 ‘CAYMAN’
OPERATING MANUAL
English

OPERATING MANUAL
22
CONTENTS
pg.
1. Description
23
1.1. Purpose
23
1.2. Delivery Package
23
1.3. Technical Specifications
24
1.4. Principles of Operation
25
1.5. Operation Modes
25
1.6. Structure
26
1.6.1. Antenna Module
26
1.6.2. Main Unit
28
2. Use
29
2.1. Preparation
29
2.2. Adaptive Mode
30
2.3. Operational check with test dummies
30
2.4. Manual Gain Control
31
2.5. Listening (Audio Mode)
33
3. Power Supply
35
4. Operating Restrictions
36
5. Storage and Transportation
36
6. Warranty
36

ST 401 ‘CAYMAN’ NLJD
23
This operating manual contains important technical information and guidance on proper use
of the product. Please read the manual before using ST 400 Cayman.
1. Description
1.1. Purpose
ST 401 CAYMAN is intended to detect and locate
•eavesdropping electronics
•mobile phones and SIM cards
•any other devices utilising semiconductor technology
ST 401 allows detecting electronic devices, whether active or not, as well as finding
their exact location. It also enables one to distinguish between return signals from real
semiconductors and other kinds of responses, such as those given by corrosion or metal-oxide-
metal structures.
1.2. Delivery package
Item
Quantity
No. in Fig.1
ST 401 ‘Cayman’ NLJD
1
1
Accumulator Battery (type 18650)
4
2
Electric Charger
1
3
Charger Power Adapter
1
4
Headphones
1
5
Semiconductor Imitating Dummy (marked red)
1
6
MOM-Structure Imitating Dummy (marked blue)
1
7
Shockproof Case
1
Operating Manual
1
not shown in figure
Fig. 1

OPERATING MANUAL
24
1.3. Technical Specifications
Range of radiated frequencies
2–3GHz
Max. peak radiated power
< 2W
Antenna polarisation
elliptic
Operation modes
SEARCH, AUDIO, ADAPT
Sensitivity range in manual mode
40dB (5 values with 8dB increment)
Visual indication
three 16-segment gauges
Aural indication
internal speaker or headphones
Power supply
two 3.7V Li-ion batteries (type 18650)
Time of operation on one battery charge
3–4 hours, depending on operation mode
Battery charging time
< 3 hrs
Operating conditions
–working temperature range
+5...+40°С
–relative air humidity
up to 85 percent (at 25°С)
Weight (with batteries)
0,85kg
Dimensions (length×width×height) folded
220х130х100mm
Weight of full set in case
5,1kg

ST 401 ‘CAYMAN’ NLJD
25
1.4. Principles of Operation
ST 401 ‘Cayman’ is a nonlinear junction detector, or NLJD. Instruments of this type employ
active detection, i.e. they emit probing signals and analyse the return. Their primary search targets
are electronic devices, and those typically consist of circuit plates with conductive elements and
various semiconductor parts connected to them, such as diodes, transistors, and microchips.
The probing electromagnetic radiation induces variable electromotive forces in these loops, and
electronic components with a non-linear current-voltage curve transform the initial signal into its
higher frequency harmonics, which come back to the NLJD’s receiver.
Higher harmonics can also be re-radiated by corroded metal or the so-called MOM-diodes,
metal-oxide-metal structures brought about by contacting metal surfaces. However, these
formations return somewhat different spectra than semiconductors.
With ST 401 one can distinguish with high probability between responses given by real
semiconductors, and those ‘faked’ by MOM-structures or corrosion.Another important advantage
is a confident detection of search targets behind partially shielding obstacles, which is achieved
by simultaneously radiating several frequencies within the 2-3GHz band and analysing the
composite picture of the reflection spectrum.
1.5. Operation Modes
The NLJD ST 401 ‘Cayman’ has the following modes of operation:
Primary operation mode: SEARCH
Secondary operation mode: AUDIO
Service mode: ADAPT
The main operation mode named SEARCH is meant for detecting nonlinear targets and
identifying them, based on the response levels as indicated by 16-segment bars.
The auxiliary operation mode named AUDIO allows demodulating the response and listening
to it through the built-in speaker or headphones. Use this mode upon detecting a response in the
SEARCH mode.
The service mode namedADAPT isused tooptimisethe parameters ina givenelectromagnetic
environment and thus maximise the effectiveness of search. Engaging this mode is necessary
every time the device is switched on. It is advisable to pause during searches from time to time,
to repeat this procedure. During adaptation, the antenna must be pointed away from electronics
and large metal objects.

OPERATING MANUAL
26
1.6. Structure
Structurally, the ST 401 ‘Cayman’ NLJD consists of the antenna module and the main unit
connected by way of a hinge joint. The general appearance of ST401 is shown in Fig. 2, the
numbers standing for:
1 –antenna module
2 –main unit
Fig. 2
1.6.1. Antenna module
The antenna module comprises a receiver-transmitter unit, a control-display unit, and an
aerial, all of which are assembled on a single platform and incorporated in a single body.
Fig. 3
The antenna module is connected with the handle through a hinge joint that allows adjusting
the incline within the vertical plane, as shown in Fig. 3. Loosen the hinge screw (2, Fig. 6) to
change the incline, then tighten the screw again.

ST 401 ‘CAYMAN’ NLJD
27
Fig. 4
On the surface of antenna facing operator, there are an indicator panel, a socket for the power-
and-control cable, and a USB port for computer connection (Fig. 4). The numbers in Fig. 4
stand for the following:
No in
Fig. 4
Description
Colour
Subscript on
indicator panel
1
16-segment led gauge of threat-type response
levels
red
1
2
16-segment led gauge of MOM-type
response levels
blue
2
3
16-segment led gauge of reflection levels
white
3
4
Power-on led indicator
red
POWER
5
SEARCH mode indicator
yellow
SEARCH
6
AUDIO mode indicator
yellow
AUDIO
7
5-segment tuning bar*
yellow
TUNING
8
socket for power-and-control cable
CONTROL
9
USB port
USB
* the TUNING segment bar has two functions:
–in the SEARCH mode, it shows the selected sensitivity of the receiver (SEN)
–in the AUDIO mode, it shows the selected frequency combination (CH 1..5)
The boresight directions of the receiving and transmitting antennas are shown in Fig. 5.

OPERATING MANUAL
28
1.6.2. Main Unit
The main unit of ST 401 ‘Cayman’ consists of a battery compartment, a control panel, and
mechanical parts that form the bearing structure. The appearance of the main unit and the location
of its components are shown in Fig. 6.
Fig. 6
The numbers in Fig. 6 stand for:
1 –bracket mount for the antenna module
2 –lever handle of the clamp
3 –power-and-control cable with plug
4 –headphone socket
5 –power and volume knob
6 –battery compartment
7–control panel
8–grid of the built-in speaker
9 –ID plate
10 –battery compartment cap
Fig. 5

ST 401 ‘CAYMAN’ NLJD
29
A three-button control panel is located in
the upper part (Fig. 7).
The MODE button (1, Fig. 7) is used
to set the operation mode of the device. A
short press of this button alternates between
SEARCH and AUDIO; holding it down for a
few seconds will set the device to the ADAPT
mode.
The other two buttons marked with arrows
and (2 and 3, Fig. 7) are for tuning
the device. Depending on the mode, they
allow:
–in the SEARCH mode, increasing
and decreasing the receiver sensitivity,
respectively.
–in the AUDIO mode, setting the desired
frequency combination.
Fig. 7
The main unit has a battery compartment for 2 type 18650 accumulator batteries. Those are
enclosed with a screw cap (10, Fig. 6) that also serves as the negative contact.
Fore of the handle are the headphone socket (4, Fig. 6) and the power and volume knob
(5, Fig. 6). In the lower part there are a speaker grid (8, Fig. 6) and an ID plate (9, Fig. 6) that
indicates:
–product name
–serial number
–logo, and name of the manufacturer company.
2. USE
2.1. Preparation
Take the device and 2 batteries out of the case. Examine the antenna module, handle, cable,
and socket for mechanical damage. Examine the batteries for mechanical damage and electrode
corrosion. Do not use the device if any such defects are found! To replace the batteries, do the
following:
•unscrew the battery compartment cap;
•insert two accumulator batteries as
shown in Fig. 8, making sure you
observe the polarity;
•screw the cap back in place.
Fig. 8

OPERATING MANUAL
30
Make sure the power switch (5, Fig. 6) is in its leftmost position (OFF). Insert the power-and-
control cord plug (3, Fig. 6) into the socket (8, Fig. 4) on the antenna module.Activate the device
by rotating the knob clockwise. The device status will be displayed on the antenna module as
shown in Table 1 below.
Table 1
Legend
Colour
Light indication
Interpretation
POWER
red
continuous
The antenna module is powered
properly.
blinking
The battery is discharged and needs
to be replaced.
TUNING
SEN
yellow
continuous
This displays receiver gain. At
startup the gain is automatically set
to maximum, which is signalled by
all the 5 indicator segments being lit.
SEARCH
yellow
continuous
This displays the operating mode.
The SEARCH mode is selected
automatically at startup.
Upon activation of the device one or more segments of the signal level gauges (1..3, Fig. 4)
may light and go out spontaneously. This would mean that the device should need to be adjusted
to the electromagnetic environment using the adaptive mode.
2.2. Adaptation mode
Toactivate this mode, press and hold for 3-4 sec the MODE button (1, Fig. 7) on the control
panel. The antenna must be directed away from large metal objects and anything that is presumed
to contain nonlinear elements (it is often best to point the antenna at either the floor or ceiling).
The adaptation takes 10–15 seconds, with all the indicators but TUNING lit in the meantime
on the antenna module. The TUNING indicator will be showing a consecutive lighting of
segments. The user can check if any of the indicator LEDs are dead.
Upon adaptation the device status will be displayed in accordance with Table 1.
Upon activation of the device one or more segments of the signal level gauges (1..3, Fig. 4)
may light and go out spontaneously. This would mean that the device should need to be adjusted
to the electromagnetic environment using the adaptive mode.
2.3. Operational check with test dummies
For that purpose, place the dummy that is marked red in an area free of responses from
nonlinear elements or reflecting surfaces.
Press button (3, Fig. 7) repeatedly to set the receiver gain at 3 lit segments of the
TUNING indicator, which corresponds to medium sensitivity.
Point the antenna at the test dummy and find the distance at which all the 16 segments of the
INPUT LEVEL Gauge bar 1 light up. For a device that is in proper working order and has self-
tuned properly, this distance should be no less than 0.8 m.

ST 401 ‘CAYMAN’ NLJD
31
Repeat the procedure using the dummy with the blue marking. In doing so, find the distance
at which all the segments of the INPUT LEVEL gauge bar 2 will be lit. For a properly working
device that has been adjusted to the environment, this distance should be no less than 0.3m.
If either distance is found to be smaller than the respective value above, it is advisable to
engage the self-tuning routine anew (see 2.2) and repeat the checks as described above.
If both distances exceed the required minimums, the device is functional and operation-ready.
2.4. Manual Gain Control
Once ST 401 has been prepared and proven functional as described above in 2.1 –2.3, it
can be put to use. When activated, the device starts up in SEARCH mode, and the receiver gain
is by default set to maximum, which is displayed by 5 lit segments of the TUNING indicator.
The SEARCH mode is the primary operation mode for ST 401. The operator can change the
receiver gain at his discretion, thus increasing or decreasing the detection range.
The gain can be varied discretely with an 8dB increment, over 5 values in a 40dB range;
each increment corresponds to one LED segment of the TUNING indicator. Thus, if all five are
lit, the gain is equal to 40dB, providing maximum detection range. If all are dimmed, the gain is
0dB, with minimum detection range. The gain can be brought a step up or down by a single
pressing of the TUNING buttons or (2 and 3, Fig. 7).
Levels of return signals from a target area are shown in the three INPUT LEVEL multi-
segment LED gauge bars (1-3, Fig. 4).
INPUT LEVEL led gauge bar 1 (16 red LEDs) displays the levels of return signals from
semiconductor material. The indication is accompanied with an alternating sound alarm.
INPUT LEVEL led gauge bar 2 (16 blue LEDs) displays the levels of return signals from
MOM (metal/oxide/metal) structures.
INPUT LEVEL led gauge bar 3 (16 white LEDs) displays the levels of return signals from
reflecting surfaces (most likely, metal).
The greater the response of a certain type, the more LEDs will light up in the corresponding
INPUT LEVEL gauge bar.
Recommendations
With an NLJD one typically probes:
•enclosing structures (walls, ceilings,floors)
•different parts of the interior
•various objects that are not supposed to contain semiconductor material
Items known to contain semiconductor components (electronic instruments, office and home
equipment, communication devices, etc.) are checked by other means.

OPERATING MANUAL
32
When running checks on enclosing structures, it is important to set a suitable receiver gain. If
excessive, it may well cause detection of objects behind the walls, which may be a problem when
there is no access into the adjoining spaces. On the other hand, if the gain is too small, targets of
interest with a weak response may remain undiscovered in the structure under scrutiny.
While scanning walls and other large vertical structures, it is recommendable to move the
antenna from top to bottom in a serpentine fashion, as is shown in Fig. 9.
Fig. 9
The antenna head should be held at a distance of 5-15 cm from the surface.
If a potent response is registered (all LEDs in an multi-segment LED gauge bar light up),
the gain should be decreased in order to establish the exact location of the responding target.
The primary task for an NLJD is the discovery of eavesdropping devices, whose giveaways
are the signals returned by semiconductor-containing electronic components and by MOM-
structures on casings, at junctures, etc. Therefore, particular attention should be paid to scanned
areas where responses have been observed on the red multi-segment LED gauge bar alone, and
on both red and blue INPUT LEVEL gauge bars. The nature of each such response should be
determined and its source identified.
Astrong, off-scale response onone ofthe multi-segment LED gauge bars maybeaccompanied
bya much weaker one on another.As a rule, the former is a true response and the latter a false one;
it is advisable to decrease the gain or move away from the target until there is noscaling-off.
Small-sized objects should be checked at locations where no response is observed on any of
the three INPUT LEVEL multi-segment gauge bars, preferably away from large metal structures,
pillars, cabinets, safes, etc.

ST 401 ‘CAYMAN’ NLJD
33
2.5. Listening (AUDIO mode)
The AUDIO mode is primarily intended for analysing target responses by listening to the
demodulated signal output. This should give the operator ample information to identify the
response type.
To switch from SEARCH to AUDIO, press MODE. The SEARCH led (5, Fig. 4) on the
antenna head will then go off, and AUDIO led will light up (6, Fig. 4).
When the AUDIO mode is on, the device status will be displayed on the antenna module as
described in Table 2 below.
Table 2
Legend
Colour
Light indication
Meaning
POWER
red
continuous
The antenna module is powered properly.
blinking
The battery is discharged and needs to be
replaced.
TUNING
yellow
continuous*
The 5-segment bar displays the selected
probing frequency combination.
AUDIO
yellow
continuous
AUDIO mode on.
INPUT
LEVEL 3
white
varying numbers of
lit LEDs
The 16-segment bar displays the levels
of returned signals. Note: in the AUDIO
mode this gauge bar shows a sum total of
responses, regardless of their type.
*Upon switching to AUDIO, none of the TUNING bar segments are lit, which corresponds
to #0 frequency combination.
The ST 401 allows listening to demodulated signals while probing with six different
frequency combinations. Each combination, indicated by LEDs on the TUNING bar, is suited
to deal with a particular category of nonlinear objects. Upon activation of the AUDIO mode,
frequency combination #0 is set by default; it is meant for probing semiconductor content and,
as a rule, gives good results in identifying active radio-transmitting and sound-recording
devices.
Frequency combination #1 is used to analyse return signals from MOM (metal/oxide/metal)
structures.
The remaining four combinations are auxiliary. Their use is advised when responses have been
observed in the SEARCH mode on the red INPUT LEVEL bar, yet probing with combination #0
has rendered no definitive findings.
Table 3 shows correspondence between frequency combinations and responses observed in
the SEARCH mode.

OPERATING MANUAL
34
Table 3
Indication on TUNING bar
Frequency combination #
0
1
2
3
4
5
Gauge bar # in SEARCH mode
1
2
1
1
1
1
Use buttons and to change probing frequency combinations (2 and 3, Fig. 7).
Table 4 shows typical results of analysing targets with nonlinear properties.
Table 4
Type of probed
target
Optimum frequency
combination
Sounds when
subjected to
mechanical impact
or test sound
Sounds in the
absence of
mechanical impact
or test sound
MOM-structure
1
crackling, creaking
none
active electronic
devices (unencoded
transmission channel)
0 (2–5)
audible response to
tapping or test sound
sounds of the
environment
active electronic
devices (encoded
transmission channel)
0 (2–5)
peculiar signals
caused by the
operation of
the device and
independent of
sounds in the
environment
peculiar signals
caused by the
operation of
the device and
independent of
sounds in the
environment
inactive electronic
devices
0 (2–5)
none
none
active electro-
mechanic or
mechanic appliances
0-5
crackling, creaking
peculiar signals
caused by the
operation of
the device and
independent of
sounds in the
environment
When listening to demodulated signals, it is recommended to use headphones. Sound volume
is adjustable with a variable resistor (5, Fig. 6).

ST 401 ‘CAYMAN’ NLJD
35
RECOMMENDATIONS
Any response observed on the red bar (or on both red and blue bar simultaneously) should be
analysed in the audio mode with the use of a test sound source. If a response has been observed
on the blue bar, it is advisable to perform audio analysis with the frequency combination #1,
subjecting the target area to mechanical impact (tapping). While probing, it is advisable to change
gradually the distance between the antenna and target within 5–100 cm range.
Push the MODE button to switch from the AUDIO mode to SEARCH.
3. POWER SUPPLY
ST 401 Cayman is powered by two Li-ion rechargeable batteries (type 18650). 4 batteries are
included in the delivery package. The total run time on one battery charge is from 3 to 4 hours,
depending on the modes employed; the most demanding in terms of power consumption is the
AUDIO mode.
The batteries is housed in the battery compartment at the back of the main unit. Battery
replacement is described in 2.1 above.
ST 401 Cayman monitors its battery charge status. A continuously lit power-on led (4, Fig.4)
on the antenna head means that the battery charge is sufficient. A low battery charge will be
signalled by blinking of the power-on LED and a warning sound. If the charge goes below the
critical threshold, the device will switch off automatically.
Accumulator batteries can be charged with the charger included in the delivery package. The
charging time of a fully discharged battery is 3 hours.As these batteries are free of memory effect,
incomplete charging is acceptable, but the running time will then be shorter.
The following is not allowed:
–long-term storage of discharged batteries
–long-term storage of batteries at low temperatures
–short-circuiting battery contacts
–subjecting batteries to strong shock
–transportation of the device with installed batteries.

OPERATING MANUAL
36
4. OPERATING RESTRICTIONS
Use of the device is subject to safety regulations for equipment incorporating UHF
transmitters. The following must be observed at all times:
•Avoid long exposure of people to the antenna beam (the main lobe of the polar diagram) at
distances less than 1m.
•Do not point the antenna at people’s eyes at distances less than 1m.
If the device has been transported at temperatures well outside the service temperature range,
make sure to keep the device indoors at service temperature for 2 hours before use.
5. STORAGE AND TRANSPORTATION
The device must be stored in heated storage facilities. The following conditions must be
maintained:
1) ambient temperatures from + 0 to 50°С;
2) relative air humidity 80 percent at 30°С;
3) atmospheric pressure from 630 to 820 mmHg;
4) absence of acidic, alkaline, or other aggressive vapours.
The device can be transported in standard packaging by any suitable means of conveyance
(in a pressurised module, if transported by plane) as long as it is protected from atmospheric
moisture. While transporting the device, avoid dropping or otherwise subjecting it to strong
impacts.
6. WARRANTY
Themanufacturerguaranteescomplianceofeverymanufactureditemwithalltherequirements
as per technical specifications, within 12 months of the date of purchase.
During the warranty period, the manufacturer guarantees free of charge repairs of the device,
its auxiliary components and accessories, up to full replacement.
Free repairs or replacement can only be claimed if the user has observed all the rules of
operation, transportation, and storage of the device, and on condition that the device itself and
its ancillary parts are free from mechanical damage, and upon submission of a properly filled out
warranty coupon.
The warranty does not cover batteries.