Lornet - NLJD. Owner`s manual.

1. Introduction
The non-linear junction detector “LORNET” (further NLJD) is used for search and location of electronic devices both in active and switch-off state. The detector operation is based on the property of semiconductor components to generate a response
at the 2d and 3d harmonics when radiated by an RF probing signal. Semiconductor
components of artificial origin will have a higher level second harmonic while semiconductor components of natural origin (e.g. oxide films) will have a higher level third
harmonic respectively. An NLJD analyzes the 2d and 3d harmonics response of the
radiated objects, which enables a quick and reliable identification of electronic devices and natural oxide semiconductors.
The NLJD “LORNET” automatically finds the best receiving frequency channel free
of noise and distortion providing flawless operation even in the complicated electromagnetic environment. The frequency tuning algorithm implemented in “LORNET”
automatically selects the RF probing signal frequency such that the noise level in 2d
harmonic receiving channel is held minimal, while digital processing of a demodulated signal gives maximum sensitivity.
There are two types of radiated signals:
- continuous wave carrier (CW);
- pulse modulated carrier with a duty cycle of 1% (pulse).
This enables to combine wide detection range and reliable identification of the devices found.
Output power automatic control mode significantly simplifies operator’s work. “LORNET” simultaneously displays the 2d and 3d harmonics levels at its LED panel. Besides, the 2d and 3d harmonics levels can be estimated in turn aurally by click repetition rate reproduced through a built-in loudspeaker or wireless earphones.
1. Specifications:
2.1. Radiated signal types:
- continuous wave carrier;
- pulse modulated carrier with a duty cycle 1%.
2.2. Carrier frequency step 0.2MHz within a tuning range of (890 … 891)MHz.
Automatic frequency selection. Possibility of radiation at the carrier frequency with a
minimum noise level in the 2d harmonic receiver path.
2.3. Maximum radiated power in the CW mode ≤2W
2.4. Peak radiated power in the pulse mode ≤10W.
2.5. Manual or automatic control of the radiated power level.
Dynamic control range of 30dB down from the maximum output power value with 11
level gradations.
2.6. Receivers sensitivity better than –150dBW given a 10dB signal to noise ratio.
2.7. Receivers tuning frequencies equal to the transmitter double and triple
2.8. Receiving path dynamic range ≥ 70dB.
2.9. Time of continuous operation with a lithium-Ion battery at the maximum radiated
- ≥3 hours in the pulse mode;
- ≥1,5 hours in the CW mode.
- unlimited operation time from 220V mains with a power adapter connected
2.10. Equipped device weight ≤1kg.
2.11. Operating conditions:
- ambient temperature 5…40C.
pressure  450mm of mercury
2. Delivery set and accessories
No. Description
Transceiver antenna assembly with an arm and control panel and a
built-in battery with a charger
Power adapter
Wireless phones including:
receiving device and earphones
User manual, certificate
The device appearance is shown in Fig. 1, where:
1- LED indicator;
2- Transceiver antenna unit combined with an indicator;
3- Telescopic arm;
4- Control panel with a power section and a battery (fixed
Wireless earphones, chargers and additional batteries are not
shown in the figure.
4. Purpose of the Detector Basic Units
4.1. The transceiver antenna unit with built-in LED indicators
(shown in Fig. 2) is used for:
 Analysis of distortion and interference in the instrument receiving path, which is made each time the transmitter is
switched on. Therefore, if an interfering signal appears during
operation (in a complicated electromagnetic environment) it is
necessary to turn the detector transmitter off and on from
time to time thus selecting an optimal frequency automatically, providing the best sensitivity and detection range of semiconductor components.
 Generation of CW or pulsed RF signal.
 Reception and digital processing of the 2nd and the 3rd freFig. 1
quency harmonics. Simultaneous display of the 2 nd and the
3rd harmonics levels gives the opportunity to distinguish with
a high reliability between signals of artificial semiconductors integrated in electronic
devices and natural corrosive ones which appear at oxidation of connecting points of
various metals.
 Demodulation of the 2nd and 3rd harmonics response, their amplification to the level
required for tapping both to earphones and a built-in loudspeaker. The amplification
is adjustable within a 20 dB range. The operator can listen to demodulated signals of
the 2nd and 3rd harmonics in turn.
 Indication of the probing signal levels (1) as well as of the 2 nd (2) and 3rd (3) harmonics levels (Fig. 2).
4.2. Hinge joint of the transceiver antenna unit with a knob is designed to transform the unit into transportation position.
(see Fig.3). Besides, it helps the operator
to fix antenna in a position convenient for
search work. Fig. 3: 1- Fixing device; 2 Hinge joint.
4.3. The control panel is used to control
operation of the detector. It consists of a
case combined with a battery and fixed
on the arm. Control board, buttons for
operation modes control and display LEDs are placed in the package. Control buttons
are divided into two groups by their function: «AUDIO» placed in the upper half of the
panel and «POWER RF» in the lower half. Control panel is shown in Fig.4 The following buttons refer to «AUDIO» group:
1- LEDs and LSTN button for switching of acoustic indication to the output of the 2 nd
or 3rd harmonics.
2- LEDs and OUT button for switching acoustic output to earphones or
a built-in loudspeaker.
3- LEDs and RF button for switching between types of the radiated
signal (CW – continuous, PULSE –
The following buttons are referred to
«POWER RF» group:
4- LEDs and PWR button to switch
on/off the probing signal transmitter.
When the instrument is switched on
Fig. 3
the automatic mode of output power
control (AUTO) is set by default. To switch over to a manual mode of output power
control (MNL) press one of the LEVEL buttons
3 a transmitter is turned on. To return to the
automatic mode turn the transmitter off and then
turn it on.
5,6 - LED and a button for receiving unit atten2
uator control.
7,8 - LEVEL buttons for control of radiated signal power in MNL and AUTO modes ( - high, 
- low). It is possible to set the maximum power
level by pressing LEVEL button ( - high,  7
low) in AUTO mode before the probing signal
transmitter is turned on.
9,10 - Volume buttons for volume control ( 6
high,  - low). Functions of control panel indicators: continuous light of any indicator correFig. 4
sponds to “on” position, absence of light – to
“off” position. Simultaneous flickering of all indicators on the panel shows that the
battery is discharged and needs to be replaced.
4.4. On the side surface of the control panel (see 1 in Fig. 5) a slide-type power
switch is placed. A slide position corresponding to «ON» is marked by a contrast
point. The device operates only when a charged battery is connected to it. A battery is
screwed on the back side of the control
panel. The appearance of a battery is
shown in Fig.6. While a battery is being
screwed on, the positive battery lead
must not be short-circuited with a case
(see 1 in Fig.5).
Attention! If the instrument has not
been in operation for a long period, it is
recommended to remove the battery
from the device and keep it separately.
4.5. Battery charging is to be made
with a power adapter and a battery
charger supplied with the instrument
Fig. 5
only. Using other chargers is not allowed.
For charging it is necessary to connect a low-voltage connector of the power adapter to
the socket placed underneath the front side of the control panel. (see 1 in Fig.6).
A red LED (see 2 in Fig.6) is lighting while charging (see 2 in Fig.6). When a battery is
completely charged, a red LED goes out, and a green LED lights up (see 3 in Fig.6).
Charging time of a fully discharged battery does
not exceed 5 hours (typical value is 3.5 h). In case
of a failure (charging is not complete within five
hours) a charger switches off automatically, both
LEDs will go out.
Рис. 6
Fig. 7
Fig. 6
4.6. Wireless telephones consist of a receiving device and earphones. Appearance of the receiving
device and position of control units are shown in
Receiving device operation order:
 Using a power adapter supplied with the instrument make sure with a help of the
charge indicator that the battery is completely charged.
 Connect head phones to a corresponding socket of a receiving device.
 Turn the receiving device on by a slide-type switch (control by the turn-on indicator).
 Using volume control set a comfortable volume level.
 If the receiving device is turned on when the detector is off, then there is only a noise
signal in the head phones at higher volume. After turning on acoustic indicator signals
corresponding to the operating mode of the detector appear in the earphones.
5. Safety Measures
5.1. By requirements of electric safety the detector corresponds to protection class 1
(according to the Russian standard).
5.2. The instrument is to be operated only by persons who have been duly instructed
“ON” indicator (lights at
Socket for phones
Socket for power adapter
Volume control
Charge indicator (lights
during charging)
Slide-type switch
Fig. 7
for safety measures while working with electric and measuring devices with open RF
energy radiators.
6. Operation Order
6.1. Remove the detector from the package, and the battery from a protective case,
connect the battery to the detector. After device transportation at negative temperatures
it is necessary to keep the device in the switch-off state at room temperature at least for
30 minutes.
6.2. To start operation set the battery and turn «LORNET» on by the power switch
placed on the control panel (Fig.5). The 2nd and 3rd indicators on the control panel will
light up, indicating that the detector has been powered on.
One yellow LED should be lighting on the antenna unit (a circle scale of the probing
signal power indicator). Its initial position corresponds to the maximum power of the
probing signal. The probing signal transmitter is off (it is turned on after pressing PWR
button only).
The 2nd and 3rd harmonics indicators should not light (flashing of the first LEDs of the 2 nd
and 3rd scales is permitted).
Turn on the probing signal transmitter pressing PWR button. This will switch on the
transmitter pulse mode and the automatic mode of signal power control. The power of a
radiated signal will change depending on a signal level at the 2 nd harmonic receiver input. In this mode sound information of the 2nd harmonic response is applied to the loadspeaker or head phones. When switching on mode 3-RD by pressing LSTN on the control unit, output power of the transmitter is adjusted automatically depending on a signal
level at the 3rd harmonic receiver input. Sound information of the 3rd harmonic response
is applied to the loudspeaker or head phones.
To switch over to the manual mode of the probing signal power control (MNL indicator
lights up) press one of LEVEL buttons after the probing signal transmitter has been
turned on. Turn the probing signal transmitter off and then turn it on for a reverse switch
If it is necessary to tap the third harmonic response turn on mode 3–RD using LSTN
button on the control panel.
During operation in premises with a lot of electronic devices, you will normally have to
decrease the level of the probing signal by 2-4 points counterclockwise from the initial
The optimum level of the probing signal is reached experimentally.
6.3. Simultaneous flashing of all indicators on the control panel indicates that the battery
is discharged and needs to be replaced urgently. In this case the power should be
turned off and the battery - replaced.
6.4. If a response signal is to be tapped by phones, switch over acoustic indication to
the head phones mode pressing the corresponding button on the control panel (see 2 in
Fig.4) and turning wireless phones on (according to their User Manual).
1) Do not direct the antenna towards the operator and people nearby.
2) While operating the device constantly monitor batteries state replacing them in-time
(by the indicators signal). The batteries must be kept fully charged.
3) Charging should be done with a charger supplied with the instrument only.
4) Self – assembling or - disassembling and use of undue chargers is forbidden.
5) When the operation is finished, or during long operation breaks, it is recommended to
remove the battery from the detector.
6) To avoid short-circuiting of leads (see 1 in Fig.6) batteries are to be kept in an isolated case when not used.
7. Search Recommendation
7.1. If possible remove electronic devices from the room examined. If it is impossible,
examination should be done at a decreased radiated power.
7.2. Set maximum radiated power level and one of the operation modes of the receiver.
7.3. In the CW mode it is recommended to use manual operation mode “Man” only.
7.4. Place the antenna unit parallel to the surface examined at the distance not exceeding 10cm.
7.5. Slowly moving the antenna unit parallel to the surface examined and changing orientation of antennas, analyze changes in the signal received at the 2 nd and 3rd harmonics visually by the indicator (aurally the click repetition rate should be maximum).
7.6. Analysis of the received 2nd and 3rd harmonics levels is made by number of LEDs
lighting on the corresponding indicator scale.
7.7. Remove the antenna unit from the surface examined or decrease output power and
repeat measurements stated in 7.5. of the present manual. For a more accurate location as well as for protection of receiving devices from overload it is possible to decrease the signal level using attenuators.
7.8. When an artificial р-n transition is found you will normally see stable lighting of the
2nd harmonic indicator LEDs. While rapping at the suspected place of a p-n transition,
readings of LEDs do not change.
7.9. When a natural р-n transition is found, you will observe stable lighting of the 3rd
harmonic indicator LEDs. While rapping at the examined surface intensively, readings
of indicators by the 3rd harmonic will change, as a rule.
The search technique offered does not reflect all nuances which may appear in each
exact case, and represents a recommendation only.
1. General
1.1. Before operation thoroughly study User Manual for «LORNET».
1.2. The Certificate is included in the delivery set and should be always kept with the
1.3. If the device is sent for repair or to a different place during operation the Certificate
is to be shipped with the instrument.
1.4. Marks in the Certificate should be done in-time.
1.5. All records in the Certificate should be made by ink only, distinctly and carefully. All
unauthorized erasures, blots and corrections are not permissible.
1.6. It is forbidden to make any notes or records in the fields and on the cover of the
2. Delivery set
Transceiver antenna assembly with
an arm and control panel and a builtin battery with a charger
Power adapter
Wireless phones
included: a receiver and earphones
User manual
Serial No
In one piece
3. Warranty
3.1. Warranty period for «LORNET» is 12 months upon supply to the customer.
3.2. Life time is 6 years.
3.3. If the device fails during warranty period provided the customer has followed all the
operation, transportation and storage rules, the manufacturer is to make the repair free
of charge or replace the device.
3.4. Warranty does not cover power elements.
4. Acceptance Certificate
Non-linear Junction
Detector «LORNET»
No ________
serial number
is manufactured and accepted according to obligatory requirements of state
standards, current technical documentation and is fit for service.
Technical inspection
date, month, year
5. Package Certificate
Non-linear Junction
Detector «LORNET»
No _____________
serial number
according to the requirements stated in the given technical documentation.
date, month, year
6. Claims Data
In case of a package damage during transportation claims are applied to the transportation organization according to the respective regulations.
If the delivery set is not complete or the NLJD is damaged, provided that its package is
not damaged, an Act is made together with a representative of the manufacturer.
If a defect appears during the warranty period, the customer is to send the NLJD to the
manufacturer with an accompanying letter, stating the reason of the claim.
All claims with a brief description of encountered problems and measures taken are
recorded in Table 1.
Table 1
Claim content
Reason, measures taken
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