I was very surprised when my simple homemade detector-indicator went off scale next to a working microwave oven in our work canteen. It's all shielded, maybe some kind of malfunction? I decided to check my new oven, it was practically not used. The indicator also deviated to the full scale!

I assemble such a simple indicator in a short time every time I go to field tests of receiving and transmitting equipment. It helps a lot in work, you don’t have to carry a lot of devices with you, it’s always easy to check the transmitter’s performance with a simple homemade product (where the antenna connector is not completely turned on, or you forgot to turn on the power). Customers like this style of retro indicator very much, they have to leave it as a gift.

The advantage is the simplicity of design and lack of power. Eternal device.

It is easy to do, much simpler than exactly the same "Detector from a network extension cord and a bowl for jam" in the medium wave range. Instead of a network extension cord (inductor) - a piece of copper wire, by analogy, you can have several wires in parallel, it will not be worse. The wire itself in the form of a circle 17 cm long, at least 0.5 mm thick (for greater flexibility I use three such wires) is both an oscillatory circuit at the bottom and a loop antenna of the upper part of the range, which ranges from 900 to 2450 MHz (I did not check the performance above ). It is possible to apply a more complex directional antenna and input matching, but such a digression would not be consistent with the title of the topic. A variable, building or just a capacitor (aka a basin) is not needed, on the microwave - two connections are nearby, already a capacitor.

There is no need to look for a germanium diode, it will be replaced by a HSMP PIN diode: 3880, 3802, 3810, 3812, etc., or HSHS 2812, (I used it). If you want to go above the frequency of the microwave oven (2450 MHz), choose diodes with a lower capacitance (0.2 pF), HSMP -3860 - 3864 diodes may work. Do not overheat during installation. It is necessary to solder point-quickly, in 1 second.

Instead of high-impedance headphones, there is an arrow indicator. The magnetoelectric system has the advantage of inertia. The filter capacitor (0.1 uF) helps the needle move smoothly. The higher the resistance of the indicator, the more sensitive the field meter (the resistance of my indicators is from 0.5 to 1.75 kOhm). The information embedded in a deviating or twitching arrow acts magically on those present.

Such an indicator of the field, installed next to the head of a person talking on a mobile phone, will first cause amazement on the face, perhaps bring the person back to reality, and save him from possible diseases.

If you still have strength and health, be sure to click on one of these articles.

Instead of a pointer device, you can use a tester that will measure the DC voltage at the most sensitive limit.

Microwave indicator circuit with LED.

Microwave indicator with LED.

Tried LED as indicator. This design can be made in the form of a keychain using a flat 3-volt battery, or inserted into an empty mobile phone case. The standby current of the device is 0.25 mA, the operating current directly depends on the brightness of the LED and will be about 5 mA. The voltage rectified by the diode is amplified by the operational amplifier, accumulated on the capacitor and opens the switching device on the transistor, which turns on the LED.

If the pointer indicator without a battery deviated within a radius of 0.5 - 1 meter, then the color music on the diode moved away up to 5 meters, both from a cell phone and from a microwave oven. As for the color music, I was not mistaken, see for yourself that the maximum power will be only when talking on a mobile phone and with extraneous loud noise.

Adjustment.

I collected several of these indicators, and they started working right away. But still there are nuances. In the on state, at all pins of the microcircuit, except for the fifth one, the voltage should be equal to 0. If this condition is not met, connect the first pin of the microcircuit through a 39 kΩ resistor to minus (ground). It happens that the configuration of the microwave diodes in the assembly does not match the drawing, so you need to adhere to the electrical diagram, and before installing, I would advise you to ring the diodes for their compliance.

For ease of use, you can degrade the sensitivity by reducing the 1mΩ resistor, or reduce the length of the wire turn. With the above ratings, the microwave fields of base telephone stations feel within a radius of 50 - 100 m.
With this indicator, you can draw up an ecological map of your area and highlight places where you can’t hang out with strollers or sit up with children for a long time.

Be under the base station antennas safer than within a radius of 10 - 100 meters from them.

Thanks to this device, I came to the conclusion which mobile phones are better, that is, they have less radiation. Since this is not an advertisement, I will say it purely confidentially, in a whisper. The best phones are modern, with Internet access, the more expensive, the better.

Analog level indicator.

I decided to try to complicate the microwave indicator a little, for which I added an analog level meter to it. For convenience, I used the same element base. The diagram shows three DC operational amplifiers with different gains. In the layout, I settled on 3 cascades, although you can also plan for the 4th using the LMV 824 chip (4th op amp in one package). Using power from 3, (3.7 telephone battery) and 4.5 volts, I came to the conclusion that it is possible to do without a key cascade on a transistor. Thus, we got one microcircuit, a microwave diode and 4 LEDs. Considering the conditions of strong electromagnetic fields in which the indicator will work, I used blocking and filtering capacitors for all inputs, for feedback circuits and for powering the op-amp.
Adjustment.
In the on state, at all pins of the microcircuit, except for the fifth one, the voltage should be equal to 0. If this condition is not met, connect the first pin of the microcircuit through a 39 kΩ resistor to minus (ground). It happens that the configuration of the microwave diodes in the assembly does not match the drawing, so you need to adhere to the electrical diagram, and before installing, I would advise you to ring the diodes for their compliance.

This design has already been tested.

The interval from 3 LEDs on to completely extinguished is about 20 dB.

Power supply from 3 to 4.5 volts. Standby current from 0.65 to 0.75 mA. The operating current when the 1st LED lights up is from 3 to 5 mA.

This microwave field indicator on a microcircuit with the 4th op-amp was assembled by Nikolai.
Here is his diagram.

Dimensions and marking of pins of the LMV824 chip.

Mounting the microwave indicator on the LMV824 chip.

Similar in parameters chip MC 33174D, which includes four operational amplifiers, made in a dip package, is larger, and therefore more convenient for amateur radio installation. The electrical configuration of the pins completely coincides with the L MV 824 microcircuit. On the MC 33174D microcircuit, I made a prototype of a microwave indicator for four LEDs. A 9.1 kΩ resistor is added between pins 6 and 7 of the microcircuit and a 0.1 uF capacitor is parallel to it. The seventh output of the microcircuit, through a 680 Ohm resistor, is connected to the 4th LED. Part size 06 03. Power supply of the layout from a lithium cell 3.3 - 4.2 volts.

Indicator on the MC33174 chip.

Reverse side.

The original design of the economical field indicator has a souvenir made in China. This inexpensive toy has: a radio, a clock with a date, a thermometer and, finally, a field indicator. A frameless, flooded microcircuit consumes negligibly little energy, since it works in a timing mode, it reacts to the inclusion of a mobile phone from a distance of 1 meter, simulating a few seconds with LED indication of an alarm with headlights. Such circuits are implemented on programmable microprocessors with a minimum number of parts.

Addition to comments.

Selective field meters for the amateur band 430 - 440 MHz
and for the PMR band (446 MHz).

Microwave field indicators for amateur bands from 430 to 446 MHz can be made selective by adding an additional circuit L to Sk, where L to is a coil of wire with a diameter of 0.5 mm and a length of 3 cm, and Sk is a tuning capacitor with a nominal value of 2 - 6 pF . The coil of wire itself, as an option, can be made in the form of a 3-turn coil, with a pitch wound on a mandrel with a diameter of 2 mm with the same wire. It is necessary to connect the antenna to the circuit in the form of a piece of wire 17 cm long through a 3.3 pF coupling capacitor.

Range 430 - 446 MHz. Instead of a coil, a coil with a step winding.

Scheme for ranges 430 - 446 MHz.

Mounting on the frequency range 430 - 446 MHz.

By the way, if you are seriously engaged in microwave measurement of individual frequencies, then you can use SAW selective filters instead of a circuit. In the metropolitan radio stores, their range is currently more than sufficient. It will be necessary to add an RF transformer to the circuit after the filter.

But that's another topic that doesn't fit the title of the post.

This RF detector was made almost from scrap parts in order to determine the presence of RF transmitting devices in the room and find their location.

The manufactured HF detector "responds" to a working mobile phone from 2 meters in talk mode, and from 4 meters in dialing mode, to a portable VHF FM radio station (145 MHz, 1 W) from 5 - 7 meters, 1500 MHz 300 mW transmitter detected at a distance of 6 meters.
The current consumption from the battery in the standby mode is 14 mA, in the indication mode - 20 mA.

Detector circuit

Excluded fragment. Our magazine exists on donations from readers. The full version of this article is only available

The RF detector circuit (Fig. 1) consists of the detector itself on germanium RF diodes VD1 and VD2, which are “supported” by a small current through the resistor R1 to increase the sensitivity, the comparator DA1 on the operational amplifier type KR140UD1208 (UD1208), the threshold of which is set by the resistor R2, and voltage reference stabilizers on the VD3 zener diode, VD4 diode and ST integrated stabilizer.

The decision to stabilize the voltage came during operation, since as the GB1 battery discharged, the switching threshold of the DA1 comparator “floated away”. To the output of the comparator DA1, through an emitter follower on a transistor VT1, an LED VD6 is connected for light and a piezo emitter Q1 with an internal oscillator for sound indication.

Parts and Assembly

Let's dwell on the details: transistor VT1 - low-power n-p-n. Operational amplifier DA1 - any other capable of operating at a supply voltage of 6 V. Diodes VD1 and VD2 - high-frequency germanium, the upper sensitivity limit of the device depends on them. Zener diode VD3 for a stabilization voltage of 3 - 4 V, for example, KS130, KS133, KS139, KS433, KS439. LED VD5 green with a voltage drop of 2 - 2.5 V.

The antenna is made of a piece of coaxial cable 100 mm long. The device is powered by a Krona battery.

Boards do not bully - no patience, unfortunately. This board is divorced with a pencil and a ruler, the copper is cut with a cutter from a hacksaw blade, divided into pads, to which all the elements are soldered.
Wiring and installation requirements - OS input circuits away from output circuits.

Setting

After checking the correct installation, we connect the power and measure the voltages indicated in the diagram. Resistor R2 sets the threshold at which the VD6 LED goes out.

Usage

We set the threshold with resistor R2, when approaching the transmitter installation area, the VD6 LED lights up, again we set the threshold with resistor R2 so that the VD6 LED goes out, etc., it may be somewhat inconvenient, but in 3-4 approaches you can accurately determine the location of the transmitter.

Often there is a need to make a simple check of the health of the RC transmitter, whether it and its antenna are working, whether the transmitter emits electromagnetic waves on the air. In this case, the simplest indicator of the electromagnetic field will be of great help. With it, you can check the operation of the output stage of any transmitter used in modeling in the range from several MHz to 2.5 GHz. They can also check the operation of a cell phone for transmission.

The device is based on a detector with voltage doubling on microwave diodes of the KD514 type of Soviet production. The principle of operation is clear from the circuit diagram. An antenna with a length of 20 ..... 25 cm is connected to the connection point of the diodes from a wire with a diameter of . 1.....2 mm. A filtering capacitor (tubular, ceramic) with a capacity of approximately 2200 pF is connected to the diodes. Diodes with a capacitor are soldered to the terminals of a microammeter, which is a device for indicating the presence of an electromagnetic field. The cathode of the right according to the diode scheme is soldered to the "+" terminal, and the anode of the left according to the diode scheme is soldered to the "-" terminal. The indicator antenna can be located at a distance from a few centimeters (2.4 GHz transmitter or cell phone) to 1 meter,
if the transmitter operates in the range of 27 ......... 40 MHz. Such transmitters have a telescopic antenna.
All details are located on a piece of textolite. The filter capacitor is located at the bottom of the scarf and is not visible in the photo.

circuit diagram

Photos.

ST 033 "Piranha" is designed to carry out operational measures to detect and localize technical means of secretly obtaining information, as well as to identify natural and artificially created information leakage channels.

The product consists of the main control and indication unit, a set of converters and allows you to work in the following modes:

• high-frequency detector-frequency meter;
• Microwave detector (Together with ST03.SHF)
• Wire line analyzer;
• IR radiation detector;
• detector of low-frequency magnetic fields;
• differential low-frequency amplifier (together with ST 03.DA);
• vibroacoustic receiver;
• acoustic receiver

The transition to any of the modes is carried out automatically when the corresponding converter is connected. Information is displayed on a backlit graphic LCD display, acoustic control is carried out through special headphones or through a built-in loudspeaker.

Provides the ability to store in volatile memory up to 99 images.

Indication of incoming low-frequency signals is provided in oscilloscope or spectrum analyzer modes with indication of numerical parameters.

ST 033 "Piranha" provides for the display of contextual help depending on the operating mode. You can choose Russian or English.
ST 033 "Piranha" is made in a wearable version. For its transportation and storage, a special bag is used, adapted for compact and convenient packing of all elements of the kit.

Using ST 033 "Piranha" it is possible to solve the following control and search tasks:

1. Identification of the fact of work (detection) and localization of the location of radio-emitting special technical means that create potentially dangerous, from the point of view of information leakage, radio emission. These tools primarily include:

• radio microphones;
• telephone radio repeaters;
• radio stethoscopes;
• hidden video cameras with a radio channel for transmitting information;
• technical means of systems of spatial high-frequency irradiation in the radio range;
• radio beacons of tracking systems for the movement of objects (people, vehicles, cargo, etc.);
• unauthorized used cell phones of GSM, DECT standards, radio stations, radio telephones.
• devices using data transmission channels using the BLUETOOTH and WLAN standards for data transmission.

2. Detection and localization of the location of special technical means working with radiation in the infrared range. These funds primarily include:

• embedded devices for obtaining acoustic information from premises with its subsequent transmission over a channel in the infrared range;
• technical means of spatial irradiation systems in the infrared range.

3. Detection and localization of the location of special technical means that use wire lines for various purposes for obtaining and transmitting information, as well as technical means of processing information that create pickups of informative signals on nearby wired lines or the flow of these signals into the lines of the power supply network. Such means can be:

• embedded devices that use 220V AC lines to transmit intercepted information and are capable of operating at frequencies up to 15 MHz;
• PC and other technical means of production, reproduction and transmission of information;
• technical means of linear high-frequency imposing systems operating at frequencies above 150 kHz;
• embedded devices that use subscriber telephone lines, lines of fire and security alarm systems with a carrier frequency above 20 kHz to transmit intercepted information.

4. Detection and localization of the location of sources of electromagnetic fields with a predominance (presence) of the magnetic component of the field, routes for laying hidden (unmarked) electrical wiring. potentially suitable for the installation of embedded devices, as well as the study of technical means that process speech information. Among such sources and technical means it is customary to include:

• output transformers of audio frequency amplifiers;
• dynamic loudspeakers of acoustic systems;
• electric motors of tape recorders and voice recorders;

5. Identification of the most vulnerable places in terms of the emergence of vibroacoustic channels of information leakage.

6. Identification of the most vulnerable places in terms of the emergence of acoustic information leakage channels.

High-frequency detector-frequency counter mode

In this mode, the product provides reception of radio signals in the range from 30 to 2500 MHz in the near zone, their detection and output for auditory control and analysis in the form of alternating tone bursts (clicks), or in the form of explicit phonograms when they are listened to both on the built-in loudspeaker and and head phones. With the use of ST033.SHF, the frequency range is increased to 10GHz.

At each specific moment of time, against the background of a real interference environment, the most powerful of all radio signals in the operating range is received and detected. Its level, relative to the set detector threshold, is displayed on a two-line indicator with a 40-segment scale in the upper part of the liquid crystal display.

The difference in the use of the two scales is as follows: the upper scale indicates the average value of the detected signal, and the lower one indicates its peak values. Accordingly, signals with a constant carrier frequency (without modulation, frequency modulation) will prevail in the top line, and signals close to pulsed types of signals (for example, signals with amplitude and pulse modulation) will prevail in the bottom line. The presence of an indication on two scales indicates a mixed signal at the detector input (for example, a television signal).

In case of reliable reception of a signal with known parameters, the inscription of signal identification is displayed under the digital scale of the signal level.

Signal detection indication of the following standards is possible: GSM, DECT, BLUETOOTH and WLAN.

Depending on the conditions and goals of conducting control and search work, it is possible to select and set the required (most rational) threshold of the detector.

At the same time, the current values ​​of the frequency of the received radio signal are measured and its most stable value is determined (for signals with a constant carrier frequency). Both those and other values ​​are explicitly displayed on the display screen.

For a qualitative assessment of the degree of frequency variability of the received radio signal, a special computational procedure is used, the results of which are displayed on the display screen in the form of a thin horizontal line of dynamically changing length directly above the digital symbols of the current values ​​of the frequency of the received signal (the dependence of the line length and frequency stability is inversely proportional, i.e. (the higher the frequency variability of the radio signal, the shorter the length of the indicating line)

Specifications

Scanning Wire Analyzer Mode

In this mode, the product provides reception and display of signal parameters in wired lines for various purposes (electrical network, telephone network, computer networks, fire and security alarms, etc.) both de-energized and energized (DC or AC) up to 600V .

Connection ST 033 "Piranha" to the analyzed line is made through a universal adapter with a set of nozzles like "220", "Crocodile" and "Needle". In addition, the adapter is equipped with an input signal attenuation device, which is activated, if necessary, by a special switch on the adapter case, as well as two LEDs to indicate the presence of AC or DC voltage in the wired line.

Signals are received by automatic or manual scanning in the frequency range up to 15 MHz. The tuning step is fixed and is 5 kHz and 1 kHz for automatic and manual scanning, respectively.

To adapt the product settings to the conditions and tasks of control and search work, it is possible to select the direction and speed of autoscanning, as well as two options for setting the necessary boundaries of the tuning range (setting the initial and final frequency or setting the center tuning frequency and range width). Classification of signals in controlled wire lines is carried out on the basis of analysis of a panorama (diagram) automatically displayed on the display screen, showing the frequency components of the spectrum of the received signal and its level on each of them. When performing manual scanning (fine tuning), the possibility of direct auditory control of the received signal is additionally provided by outputting it to the built-in loudspeaker or headphones.

Specifications

IR detector mode

In this mode, the product, using a remote sensor, ensures the reception of infrared radiation sources in the near zone (within a specific room at the site of special works), their detection and output for auditory monitoring and analysis in the form of either alternating tone bursts (clicks), or in the form of explicit phonograms when listening to them both on the built-in loudspeaker and on headphones.

At each specific moment of time, against the background of a real interference environment, the most powerful of all signals in the operating range is received and detected.

Its level, relative to the set threshold of the product detector, is displayed on the LCD indicator with a 21-segment scale. At the same time, depending on the conditions and objectives of the control and search work, it is possible to select and set the necessary (most rational) threshold of the product detector.

Together, this provides the possibility of prompt preliminary classification of signals and their sources.

Specifications

Low frequency magnetic field detector mode

This mode provides reception on a magnetic antenna and display of signal parameters from sources of low-frequency electromagnetic fields with a predominant (available) magnetic field component in the range from 300 to 5000 Hz.

The classification of signals and their sources is carried out on the basis of an analysis of an oscillogram automatically displayed on the display screen, which displays the shape of the received signal and the current value of its amplitude. Increasing the reliability of the classification of signals and their sources is provided by the possibility of simultaneously analyzing the image on the display screen, listening to the "background" environment using the built-in loudspeaker or headphones.

To work in a difficult interference environment, the so-called differential antenna mode is provided, which is activated by a switch on its body.

Specifications

Vibroacoustic receiver mode

In this mode, the product provides reception from an external vibroacoustic sensor and displays the parameters of low-frequency signals in the range from 300 to 6000 Hz.

The state of vibroacoustic protection of premises is assessed both quantitatively and qualitatively.

Quantitative assessment of the protection status is carried out on the basis of analysis of an oscillogram automatically displayed on the display screen, showing the shape of the received signal and the current value of its amplitude.

A qualitative assessment of the state of protection is based on direct listening to the received low-frequency signal and analysis of its loudness and timbre characteristics. To do this, use either the built-in loudspeaker or headphones.

Specifications

Acoustic receiver mode

In this mode, the product provides reception to an external remote microphone and displays the parameters of acoustic signals in the range from 300 to 6000 Hz.

The state of soundproofing of premises and the presence in them of vulnerable, from the point of view of information leakage, places is determined both quantitatively and qualitatively.

Quantitative assessment of the state of soundproofing of premises and identification of possible information leakage channels are carried out on the basis of an analysis of an oscillogram automatically displayed on the display screen, reflecting the shape of the received signal and the current value of its amplitude.

Qualitative assessment is based on direct listening to the received acoustic signal and analysis of its loudness and timbre characteristics. To do this, use either the built-in loudspeaker or headphones.

Specifications

Differential low-frequency amplifier mode (together with ST033.DA)

This mode provides reception and display of signal parameters in wire lines with voltage up to 70 V, in the audio frequency range (300–6000 Hz). In this mode, it is possible to detect:

• microphones, both active and passive (not having a pre-amplifier);
• "microphone effect" from office equipment, household electrical equipment, security and fire alarms, etc. in the line under study.

ST 033 is connected to the analyzed line through a differential amplifier (ST033.DA) using special nozzles. The balanced input allows you to effectively suppress external interference signals. Detection of dangerous signals in the line is carried out on the basis of analysis of the oscillogram or spectrogram displayed on the screen and listening to the acoustic signal. To do this, use either the built-in loudspeaker or headphones.

General technical characteristics ST 033 "PIRANHA"

High frequency detector-frequency counter
Operating frequency range, MHz	30-2500
Sensitivity, mV	<2 (200МГц-1000МГц) 4 (1000MHz-1600MHz) 8 (1600MHz-2000MHz)
Dynamic range, dB	60
Frequency meter sensitivity, mV	<15 (100МГц-1200МГц)
Frequency measurement accuracy, %	0,01
Scanning Wireline Analyzer
Scan range, MHz	0,01-15
Sensitivity, at s / w 10 dB, mV	<0,5
Scan step, kHz	5(1)
Scanning speed, kHz	50-1500
Bandwidth, kHz	10
Adjacent channel selectivity, dB	30
Detection mode	AM, WCH
Permissible voltage in the network, V	600
IR detector
Spectral range, nm	770-1000
Threshold sensitivity, W/Hz 2	10(-13);
Field of view angle, deg.	30
Frequency band, MHz	5
LF magnetic field detector
Frequency range, kHz	0.3-10
Threshold sensitivity, A / (m x Hz 2)	10(-5)
Vibroacoustic receiver
Sensitivity, V x sec 2 / m	1
Intrinsic noise in the band 300Hz-3000Hz, μV	50
Acoustic receiver
Sensitivity, mV/Pa	>=5
Frequency range, Hz	300-6000
Oscilloscope and spectrum analyzer
Bandwidth, kHz	22
Input sensitivity, mV	10
Measurement error, %	1
Oscillogram output speed, s	0,2
Spectrogram output speed, s	0,3
Indication
LCD graphic display with a resolution of 128x64 dots with adjustable backlight
Supply voltage, V	6(4 batteries or AA batteries)/220
Maximum consumed current, no more than, mA	300
Current consumption in operating mode, no more than, mA	150
Dimensions, mm
Main unit	180x97x47
Packing bag	350x310x160
Weight, kg
Main unit	0.7
Gross	4.5

Completeness of delivery

Name	Quantity, pcs
1. Main control, processing and display unit	1
2. Active RF antenna	1
3. Scanning Wireline Analyzer Adapter	1
4. Nozzle type "220"	2
5. Attachment type "Crocodile"	2
6. Nozzle type "Needle"	2
7. Magnetic sensor	1
8. IR sensor	1
9. Acoustic sensor	1
10. Vibroacoustic sensor	1
11. Telescopic antenna	1
12. Headphones	1
13. AA battery	4
14. Shoulder strap	1
15. Main unit stand	1
16. Power supply	1
17. Bag - packing	1
18. Technical description and operating instructions	1
Optional
1 Microwave detector "ST03.SHF"
2 Differential low-frequency amplifier "ST03.DA"
3 Control device "Test"

Additional equipment for ST 033

Microwave radiation detector "ST 03.SHF"

ST 03.SHF is designed to work together with ST 033 and ST 034 products.

ST03.SHF consists of two units structurally located on the same printed circuit board: a log-periodic antenna-detector and an amplification unit.

Amplitude - frequency response is shown in Figure 1

Specifications

Frequency range, with uneven frequency response ± 8dB, GHz
Threshold sensitivity, W/cm2
Dynamic range, dB
Antenna type	log-periodic
Polarization	Horizontal
Beam width, deg
Dimensions, mm
SHF	230x45x24
Package	265x 125x 0
Weight, no more than, kg
SHF
GROSS

Complete set, piece

"ST 033.DA"

ST 033.DA is designed to work together with ST033 and ST033P products

ST033.DA is used to detect surreptitious information retrieval devices that use wire lines to transmit information in the acoustic frequency range;

Symmetrical input ST033.DA allows you to effectively suppress external interference signals.

Main technical data

ST 033.DA IS NOT INTENDED TO TEST LINES WITH VOLTAGE MORE THAN 70V.

Recommendations for conducting control and search work using the item ST 033 "PIRANHA"

The effectiveness of using the ST 033 "Piranha" product for carrying out control and search work is determined by: the degree of preparedness of the operator to use the product; completeness and quality of preparatory activities; compliance of the operator's actions with the general rules and methods tested in practice.

The operator must have stable skills in preparing, testing and controlling the product in the prescribed modes, as well as skills in analyzing the results of auditory and visual (according to oscillograms and spectrograms) monitoring of the parameters of potentially dangerous signals.

Preparatory measures are usually carried out in two stages. The first of these is the preliminary preparation stage, and the second is the direct preparation stage.

The preliminary stage consists, first of all, in an advance detailed study of the object of the forthcoming control and search work. At the same time, the conditions for the location of the object are studied (the nature of the external territory, the presence and purpose of adjacent, above and below the premises), as well as its design features (size, ceiling height, material and technology for erecting walls and partitions). In addition, important at this stage, the design of the interior of the room (composition, type and placement of furniture) and saturation with technical means (PC, copiers, faxes, telephones, household appliances, etc.) are important. It is considered expedient to record the obtained data in one form or another (up to photographing). At this stage, the presence and routes of wired and other potentially dangerous communications should be identified.

Certainly necessary is their certification or, at least, the presence of scaled schemes of the power supply network, subscriber telephone network, fire and security alarm systems, heat and water supply routes, ventilation. The data obtained during the preliminary stage serve as the basis for preparing the object and the item ST 033 "Piranha" directly to the start of work.

The procedure for carrying out direct training largely depends on the goals and specific tasks of control and search work, on the degree of intended use of the modes and capabilities of the product. Therefore, the content of direct preparatory measures, as well as the basic rules (techniques) for performing control operations, are most conveniently considered in relation to each type of control and search work and the mode of use of the product.

At the same time, there is a general, proven by practice, RULE. It consists in the fact that in all cases it is necessary to EXCLUDE THE PRESENCE ON THE CONTROLLED OBJECT (IN THE CHECKED ROOM) OF PERSONS NOT RELATED TO THE PREPARATION AND CONDUCTION OF THE CHECK.

1 Using the product to identify information leakage channels in the radio frequency range

These channels can be created artificially (intentionally), through the use of special technical means by interested bodies and organizations (radio microphones, telephone radio repeaters, unauthorized radio stations, radio beacons, etc.). They can also arise naturally, due to spurious electromagnetic radiation (SEMI) of technical means of information processing (PC, telexes, faxes, etc.).

In any case, it becomes necessary to classify signals in the radio frequency range according to a set of criteria.

1.1. One of the practical approaches to the classification of radio signals

From the point of view of solving the problems of information security control and using the ST 033 "Piranha" product, all radio signals falling within its operating range can be quite objectively divided into DANGEROUS and NON-DANGEROUS.

Useful for practice is also the classification of radio signals according to the most likely place of their occurrence (INTERNAL and EXTERNAL), relative to the object (premises) being checked.

DANGEROUS radio signals can be generated by both internal and external sources. Moreover, in practice there is a fairly large number of their most diverse combinations.

Typically, purely INTERNAL HAZARDOUS radio signals include:

• "radio bookmark" signals (radio microphones, telephone radio transmitters, etc.).
• radio beacon signals;
• signals of unauthorized radio stations and radiotelephones included in the premises;
• spurious electromagnetic radiation of a PC and other technical means of information processing.
  The category of HAZARDOUS, in the combination "INTERNAL-EXTERNAL", is usually referred to as radio signals, the sources of which can be:
  • radio microphones with an external acoustic microphone;
  • telephone radio repeaters installed on the communication line outside the premises (but near it);
  • radio stethoscopes installed on the outside of the surfaces enclosing the room;
  • remote transmitters of hidden video cameras;
  • devices for external high-frequency irradiation.

Purely EXTERNAL sources of radio emission, as a rule, do not pose a direct DANGER in terms of information leakage. These include broadcast radio stations, television broadcasting stations, radio communications, etc.

As sources of INTERNAL NON-DANGEROUS radio signals, first of all, electrical appliances, office equipment, household appliances, as well as their power supplies can be considered.

Given the variety of sources of potentially dangerous signals when working with the product

ST 033 "Piranha" use two main methods of their search and localization.

1.2. Methods for searching and localizing sources of dangerous radio signals

In practice in general, and when working with the ST 033 "Piranha" product in particular, two main methods of searching and locating sources of dangerous radio signals are used separately or in combination. They are the so-called "Amplitude method" and the "Acoustic tie-in" method.

"Amplitude method" is based on a sharp increase in the level of the received signal when the receiving antenna of the product approaches the location of its source. The radius of the source detection zone depends on the power of the signal emitted by it, the directivity of its antenna and the electric field background level at the location of the receiving antenna of the product.

After fixing the fact of detecting a potentially dangerous radio signal, you should move in the direction of increasing its level. Control over the level of the received signal must be carried out according to the readings of the level indicators on the display screen of the product and the frequency of clicks of the sound signal in the "TONE" mode.

A sign of the occurrence of "acoustic binding" is the appearance of a characteristic "squeak", the tone and intensity of which change when the speaker of the product approaches the microphone of the "radio bookmark".

It should be borne in mind that the presence of a characteristic sound when using this method unmasks the work being done. Therefore, in the case of using "radio bookmarks" with remote control, they can be turned off for the duration of the test.

The rational choice of one or another method largely depends on the characteristics inherent in potentially dangerous radio signals and their sources.

1.3. Features of potentially dangerous radio signals and their sources

As already noted, the sources of potentially dangerous radio signals are radio microphones, telephone radio repeaters, radio stethoscopes, hidden video cameras with a radio channel for transmitting information, radio bookmarks in a PC, spatial high-frequency irradiation, unauthorized communications (radio stations, radio telephones, telephones with radio extension cords).

Due to the wide variety of options for the design and circuit design of radio microphones, they are also characterized by a wide range of features of radio emissions.

1.3.1. radio microphones

Are widespread radio microphones with parametric frequency stabilization transmitter. The main feature is the large limits of carrier frequency change (up to several megahertz). Therefore, for the localization of radio microphones of this type, it is most expedient to use the "acoustic tie-in" method.

Quite widely used radio microphones with quartz frequency stabilization and narrowband frequency modulation. Their main features are in a small range of carrier frequency changes (up to ten kilohertz) and a weak sound signal at the output of the amplitude detector of the product receiver. The latter determines the much smaller size of the zone of occurrence of "acoustic binding". Therefore, to search for and localize sources of this type, it is most expedient to use the amplitude method.

As highly professional means of secretly obtaining information, radio microphones with remote transmitter. Their main feature is the spacing of the microphone installation sites and the radio transmitter itself (up to removal to another room). In this case, a combination of the "acoustic binding" method and the amplitude method is necessary. Moreover, for the localization of the microphone, it is necessary to use the "acoustic binding" method, and the radio transmitter (in the room being checked or outside it) - the amplitude method.

Highly professional means are radio microphones with a closed or masked radio channel. Their main feature is that the received and demodulated signal does not contain information about the acoustic background of the room. This is determined by the use of spectrum inversion methods, digital transmission methods and complex types of modulation to close (mask) the radio channel. Therefore, their detection and localization should be based on the amplitude method, supplemented by the analysis of oscillograms and spectrograms in the "OSC" and "SA" modes, respectively.

For radio microphones intended for installation in cars and other vehicles, there are two main features - increased power of the radio transmitter and a cleaner, without signs of external background, demodulated signal (due to the soundproofing properties of the car body). Other features may appear depending on the methods used to stabilize the carrier frequency and the types of modulation used.

Therefore, the methods for searching and localizing such radio microphones are completely similar to those discussed above.

1.3.2. Telephone repeaters

Despite the variety of options for the execution of telephone radio repeaters, two groups are clearly distinguished according to the method of connecting to telephone line elements - with and without galvanic contact. In this case, the galvanic connection can be carried out both in series (into the break of one of the wires of the telephone line) and in parallel (simultaneously to two wires of the telephone line).

Serial telephone radio repeaters differ in the main feature - the appearance of a modulated signal on the air only when the handset of the telephone is raised. At the same time, PBX signals ("call", "busy"), dialing clicks, conversation of subscribers after the connection is established are clearly listened to. In principle, such a radio repeater can be installed practically on any part of the telephone line (the body of the device, its handset, junction boxes and shields, the wires of the subscriber line itself). Localization of telephone repeaters of this type is most expedient to carry out by the amplitude method.

This is due to the fact that the telephones currently in use have sufficiently sensitive microphones and, often, a speakerphone mode. The use of the "acoustic tie-in" method can lead to false conclusions about the presence of an installed telephone radio repeater.

Parallel telephone radio repeaters may be of two types.

The first of them provides for the implementation of only the relay function. At the same time, in the off-hook mode, at the radio frequency, PBX signals ("call", "busy"), dialing clicks and conversation of subscribers are heard. When the handset is on-hook, there is no modulation of the radio signal, and the carrier frequency itself may be absent. Such a radio repeater can in principle be installed on any section of the telephone line. To localize bookmarks of this type, the amplitude method is preferable with their activation by picking up the handset of the telephone set.

In the second variety, they often combine the functions of a telephone radio repeater and a radio microphone powered by a telephone line and providing room acoustics control in on-hook mode. Such bookmarks are installed on the elements of the telephone line within the premises of interest. For their localization with the handset on-hook, the "acoustic binding" method is used with the use of a test sound signal. In the off-hook mode, the amplitude method is preferable for localizing such bookmarks.

It must be borne in mind that galvanically connected radio repeaters, as a rule, do not have their own antennas, but use telephone line wires instead. In this case, their localization can be carried out only by the amplitude method by identifying the distribution of the high-frequency electromagnetic field level maxima along the telephone line. The maxima alternate after half a wavelength, and the closest one, in relation to the transmitter, is removed from it at a distance of a quarter of a wavelength.

The wavelength is determined in accordance with the value of the frequency "captured" by the frequency counter of the product. For example, at a radiation frequency of 300 MHz, the wavelength is 1 meter. Consequently, the radiation maxima for this case will alternate after 0.5 meters, and the most probable installation sites of such radio repeaters will be at a distance of 25 centimeters from the maximum points.

Telephone radio repeaters without galvanic connection(inductive retrieval of information) can be installed on any section of the telephone line, as a rule, outside the premises of interest on the subscriber wiring without breaking the insulation. They form a modulated radio signal only when the handset of the telephone is picked up. At the same time, PBX signals ("call", "busy"), dialing clicks, conversation of subscribers after the connection is established are listened to. Their localization is carried out by the amplitude method as the telephone line is surveyed throughout its available length.

1.3.3. Other sources of potentially hazardous radio emissions

Here, one should consider, first of all, radio stethoscopes, hidden video cameras with a radio channel for transmitting information, radio bookmarks in a PC, radio beacons, spatial high-frequency irradiation, unauthorized means of communication (radio stations, radio telephones, telephones with radio extension cords).

The main feature of radio stethoscopes consists in the fact that they are installed only on the outside of the surfaces enclosing the controlled room, or on pipes of heating systems, water supply and other communications that go beyond it. To detect their signals, you can use the "AUD" mode and classification "by ear", and to localize sources of radio emission - the amplitude method with the movement of the product to adjacent, above and below located rooms.

Hidden video cameras with a radio channel for transmitting information differ in that the signal emitted in the radio range is similar in structure to the signal of the brightness channel of television broadcast transmitters. This signal, according to the above classification, is INTERNAL (relative to the checked room). It is most expedient to detect such a signal and localize its source using the amplitude method, supplementing this method by listening to the change in the tone of the detected signal in the "AUD" mode and analyzing the change in the signal structure in the "OSC" and "SA" modes.

Radio bookmarks in a PC designed to transmit the monitor image and digital signals of the system unit and other elements of the physical architecture of the computer. Their main feature is that the signal transmitting the monitor image is similar in structure to the signal of the transmitter of a hidden video camera, and in other cases contains all the signs of a digital transmission. The basis for their detection and localization is the amplitude method, supplemented by image analysis in the "OSC" and "SA" modes.

Radio beacons differ in that their radio emission is not modulated by the acoustic background of the room (object), it is continuous or distinctly periodic. It is possible to modulate the tone. Their detection can be carried out by the amplitude method in combination with listening to the signal in the "AUD" mode, and localization - only by the amplitude method.

Means of spatial high-frequency irradiation are EXTERNAL and are used to obtain information from the premises by focusing on it (mainly through window openings) a powerful highly directional beam of high frequency electromagnetic radiation and receiving a re-emitted (already modulated) signal at higher harmonic frequencies. The main features that provide the possibility of their (means) detection and localization are that the probing signal is stable in frequency, its modulation is absent, the level is uneven (higher in the window area, significantly lower in the corridor and other rooms). In addition, the reradiated signal corresponds in frequency to the higher harmonics of the probing signal and is modulated by the acoustic background of the room. Therefore, the detection of such means is carried out by the amplitude method in combination with listening to the signal in the "AUD" mode, and the localization of the irradiation direction is carried out only by the amplitude method.

The main feature of unauthorized transmission radios, radiotelephones and telephones with radio extensions is significantly lower than that of radio microphones, the sensitivity of the built-in microphone. In addition, many of them (especially radiotelephones) use complex types of modulation. This leads to the fact that in the received and detected radio signal, either the acoustic background of the room is not heard, or "acoustic tie" occurs in close proximity to such means. For their search and localization, one should focus on the amplitude method.

1.4 Basic rules for the preparation and conduct of control and search work

Work begins with the preparation of a controlled room (object) and the product itself ST 033 "Piranha".

The initial stage of preparation of the room is to create such conditions under which the minimum possible level of the background of the electric field is provided. This is achieved by turning off potential sources of background increase, which are considered to be office equipment, PCs, converters and power supplies, wireless telephone base stations, fluorescent lighting lamps and other electronic devices and electrical appliances. It is also advisable to close windows and doors, lower (push) curtains or blinds.
PARTICULAR ATTENTION SHOULD BE TURNED OFF TO RADIO TELEPHONES AND OTHER RADIO-TRANSMITTING EQUIPMENT, AS WELL AS ACTIVE RADIO ENGINEERING PROTECTION IF THE ROOM IS CHECKED OR ADJACENT WITH THEM EQUIPPED WITH THEM. THE ST 033 "PIRANHA" PRODUCT IS NOT ALLOWED TO WORK SIMULTANEOUSLY WITH NON-LINEAR LOCATORS.
If the object of the check is a car, then it is necessary to choose the right place of work in terms of reducing the level of electromagnetic background. So, high-voltage power lines, transformer substations, emitting means of communication, television and radio broadcasting, as well as large reflective (re-radiating) surfaces - metal fences, walls of houses, garages, other cars should not be located near it.

The search for potentially dangerous radio signals and their sources is usually carried out sequentially, one by one checking for the presence of:

• autonomous radio microphones and telephone radio repeaters;
• camouflaged radio microphones powered by the mains;
• radio stethoscopes;
• hidden video cameras with a radio channel;
• spatial high-frequency irradiation;
• radio bookmarks in a PC.

To create an acoustic background and to activate radio bookmarks with an acoustic start, a test sound source should be prepared and placed in a controlled room. As such a source, you can use a tape recorder with a well-known musical or speech soundtrack. It is not recommended to use a radio receiver or a TV for this purpose, since the sound signal generated by them, re-emitted by the "radio bookmark", may coincide with the radio signal of the broadcasting station itself. The choice of the volume of the test sound signal is determined both by the size of the room and by the sensitivity of the "radio bookmark" microphone. Typically, such microphones confidently perceive sound of medium volume from a distance of about 10 meters.

The preparation of the ST 033 "Piranha" product itself (after checking its performance in this mode) consists in setting the "zero" threshold of the detector, which is, in fact, decisive for successful work. Understating the threshold will necessarily lead to frequent false alarms of the indication, and its overestimation - to the probable omission of the "radio bookmark" signal. Both greatly complicate the work of the operator, increase the time and reduce the reliability of the test results. Therefore, to set the "zero" threshold, it is necessary to follow a few simple rules.

It is impossible to set the threshold in the room being checked, since when the already placed "radio tab" is functioning in it, the level of its radio emission will be determined by the product as "zero".

When setting the threshold, it is unacceptable to use radio stations, radiotelephones and other radio-emitting means.

Do not bring the antenna of the product closer to the included PC and other office equipment, as sources of PEMI in the range of the product.

Do not allow the product antenna to come into contact with metal objects and wires as sources of re-radiated high-frequency signals.

Therefore, the adjustment of the device should be carried out in one of the rooms closest to the checked room, in which, presumably, the background level does not differ significantly, and the installation of "radio bugs" is either impossible or impractical. As such premises, premises of a different purpose are usually considered, but located on the same floor and with window openings facing the same side of the building.

If the object of the check is a car or other vehicle, then, having ensured the correct choice of the place of work, the setting of the "zero" threshold should be carried out no closer than 10-20 meters from it.

After setting the "zero" threshold, the product is moved to the controlled room (to the controlled object) WITHOUT POWER OFF. For each subsequent inclusion of it leads to the automatic setting of the threshold already in relation to the new conditions of the electromagnetic environment.

Having fulfilled the above rules and restrictions, it is possible to consider the checked room (object) and the ST 033 "Piranha" product prepared for control and search work. It is advisable to search for autonomous radio microphones and telephone radio repeaters by disconnecting the power cords of all authorized consumers from the power outlets and turning off the lighting devices with incandescent lamps. Taking into account the fact that the radio frequency path of the ST 033 "Piranha" product is made according to the combined detector-frequency meter scheme, the same techniques and methods are suitable for its use as for autonomous field detectors, interceptors and radio frequency meters. In general, they are as follows.

If restrictions are not imposed on the secrecy of the work, then the best effect is given by a combination of the amplitude method and the "acoustic tie" method. When conducting a covert search, it is necessary to focus on the amplitude method with listening to the detected signals through headphones.

Particular attention is paid to radio emissions in the range of 60-640 MHz, which is most typical for use by radio microphones and telephone radio repeaters. The search is carried out by systematically bypassing the room (object) with movement along the walls and examining furniture and other objects located in it. In view of the sufficiently high sensitivity of the high-frequency antenna, it is advisable to start the search using a telescopic antenna. When bypassing, the antenna must be oriented in different planes, making smooth, slow turns of the main unit and achieving the maximum signal level. It is advisable to keep the product antenna at a distance of no more than 20-25 cm from the examined surfaces and objects. If there are no restrictions on the use of the "acoustic binding" method, the speaker of the built-in loudspeaker of the product should be oriented towards the surfaces and objects being examined.

When the antenna of the product ST 033 "Piranha" approaches the location of the "radio bookmark", the intensity of the electromagnetic field increases, and the signal level at its input increases accordingly. With the signal level exceeding the set "zero" threshold, depending on the type of signal, the number of colored sectors of one of the lines of the level indicators increases and, starting from the fourth (counting from the zero mark), the frequency of clicks of the sound alarm in the "TONE" mode increases, and when when the "AUD" mode is turned on and the loudspeaker dynamics, an "acoustic tie" occurs.

If a source with a frequency modulated signal is found, the number of colored sectors of the upper signal level indicator will increase. When close enough to the source, the radio frequency meter "captures" the frequency and shows its value in the last line of the screen based on the results of several measurements. By reducing the volume with the "-" button, changing the boundaries of the dynamic range with the "SET" button, manually increasing the detector threshold, constantly monitoring the frequency meter readings, the examination area narrows and, thereby, the location of the "radio bookmark" is localized with an error of 10-15 cm Additional possibilities, first of all, according to the classification of radio emissions, are provided by periodically switching on the "AUD" mode and listening to the demodulated signal.

However, it must be remembered that the effect of "acoustic coupling" and a distinct listening to the demodulated signal are not always observed. For example, if bookmarks have a masked radio channel. Therefore, their search is based on the use of the amplitude method in its purest form. Complementary here can be a simple trick. If you turn off the source of the test soundtrack and create a short sharp sound in the test room (strong bang, hit on the table top or a metal object), then you can fix the characteristic changes in the demodulated signal "by ear" in the "AUD" mode, changes in the oscillogram in the "OSC" mode and spectrograms in "SA" mode.

In the case of using a "radio bookmark" with digital modulation methods, the level increase will be indicated on the lower indicator. Indication of the frequency of the received signal in this case will be random.

In the case of using DECT or GSM phones as a "radio bookmark", in addition to indicating an increase in the signal level in the bottom line, the indicator will display the inscription DECT or GSM.

Similarly to the search for radio microphones, the search for telephone radio repeaters is carried out. At the same time, to activate them, it is necessary to pick up the handsets of all telephone sets. The search itself is carried out in two stages.

First, the telephone sets themselves are checked for the presence of embedded devices. The radio repeater installed in the device appears in the same way as the radio microphone. When the product antenna approaches such a telephone set, the means of sound (in the "TONE" mode) indication, the signal level indicator and the frequency meter react. When switched to "AUD" mode, either a continuous or intermittent telephone exchange tone is heard in the speaker or headphones. In some cases, when the microphone of the handset approaches the speaker of the ST 033 "Piranha", the effect of "acoustic tie-in" may occur. It is not recommended to test telephones in the speakerphone mode (if it is provided), since in this case a false "acoustic link" may occur between the microphone and the speaker of the device itself.

Further, the search for telephone radio repeaters is carried out by bypassing the premises along the subscriber telephone line and identifying places on it with an increase (maximum) of the radio signal level. When bypassing the antenna of the product, it is necessary to orient it in different planes at the minimum possible distance from the line. Almost always there is a need to check the line up to the main switchboard. Particular attention should be paid to junction boxes and places where the line is laid with hidden wiring. Telephone radio repeaters installed on the line are localized mainly by the amplitude method, supplemented by checking for the occurrence of "acoustic coupling".

The search for camouflaged radio microphones powered by the mains, and the localization of their installation site, is carried out by the same methods that were described above. To activate them, you must turn on the test sound source. Turn on existing incandescent lighting fixtures in turn and connect power cords of authorized consumers to power outlets. Consistently conduct a survey of each of the newly connected funds.

The search for radio stethoscopes has certain features due to the way they are used (installation outside the controlled area). Therefore, in order to detect signals from radio stethoscopes, it is necessary to examine all really accessible external surfaces of the structures enclosing the room. Since the propagation medium of vibroacoustic oscillations can be heating and water supply pipes, these communications are also subject to verification.

The vast majority of radio stethoscopes use an open radio channel. This makes it possible to analyze the received signal "by ear" in the "AUD" mode. When checking the enclosing structures, the antenna of the product should be located at the minimum possible distance from the surfaces being examined, since the radius of the signal detection zone from a radio stethoscope is usually less than from radio microphones. When checking pipeline communications, it is necessary to follow the same recommendations, but do not allow the antenna to come into contact with metal surfaces.

Localization of radio stethoscopes is carried out by the amplitude method in adjacent rooms, supplemented, if necessary, by using the "OSC" and "SA" modes.

The search for hidden cameras with a radio channel for transmitting images (often also sound) is fraught with some difficulties, which are determined by the similarity of the video transmitter signal with the brightness signal of television broadcast transmitters and the operation of a significant number of these devices in the range of television stations (from 60 to 500 MHz).

Therefore, in the course of work, when such a signal is detected, the first task is to recognize it according to the "external-internal" criterion. For recognition, it is necessary to close the windows with curtains or blinds, leaving the interior lighting on. Switch artificial lighting on and off several times. When the "AUD" mode is on, distinct changes in the tone of the detected signal should be heard. To improve the reliability of recognition, turn on the "OSC" mode and make sure that the signal structure changes according to the oscillogram when the lighting is turned on and off. The oscillogram of the radio signal for transmitting video information for various values ​​of the horizontal scanning parameters is shown in Figures 7 and 8.

If the results of such a check are positive, then the signal can be confidently classified as internal, created by the transmitter of the video camera, since a change in the illumination of the room does not affect the parameters of the television broadcast signal.

In principle, video camera transmitters can operate at frequencies up to 2300 MHz. The detection of a signal (similar to a luminance signal) at frequencies outside the range of television broadcasting almost unambiguously indicates the operation of a hidden video camera transmitter.

The localization of such means is carried out by the amplitude method.

With regard to spatial high-frequency irradiation, the main task is to identify the fact of creating this artificial channel for obtaining information. Usually it is solved in two stages. At the first stage, the fact of irradiation of the room with a high-frequency signal is revealed. At the second stage, the response to the probing high-frequency signal is monitored. In doing so, it is necessary to focus on the following points.

Based on this, the following workflow can be used.

To identify the fact of high-frequency exposure, one by one examine potentially dangerous window openings. To do this, bring the antenna to the inner glass at a distance of 5-10 cm, fix the level and frequency of the most powerful signal. Turn on the "AUD" mode and "by ear" to determine the presence and features of the demodulated signal. Using the graphical indicator, evaluate the stability of the radiation frequency. Go to any of the neighboring rooms (with windows oriented in the same direction) and repeat the check in the area of ​​each of its window openings. High frequency exposure is likely if:

• the frequency of the received signal lies (or is very close) within the specified range;
• high frequency stability;
• no signal modulation;
• in the adjacent, in relation to the tested, premises, the level of the received signal is significantly lower.

To identify sources of re-radiation, it is necessary to carefully examine each of the potentially dangerous objects, placing the antenna of the product in close proximity to it. The basis for making the final decision about exposure and the presence of re-emitting objects in the room is the readings of the level indicator of the ST 033 "Piranha" product and its frequency meter, as well as the results of listening in the "AUD" mode. In this case, the main features are usually considered fixing the nominal frequency, a multiple of the maximum third harmonic of the irradiating signal, and identifying the sound signal in the "AUD" mode with the acoustic background of the room.

It is advisable to check the PC for the presence of "radio bugs" in them last. This is due to the fact that in the on state they create quite intense spurious radio emissions in the range up to 1000 MHz and higher, that is, they are sources of an increase in the electromagnetic background, which can "mask" the radiation of the previously considered radio bugs. It should be borne in mind that "radio bookmarks" can transmit both signals corresponding to the image on the monitor screen, and signals that carry digital information processed by the elements of the system unit. Both those and other signals have fairly distinct external signs that appear on their oscillograms in the "OSC" mode. The former are similar in structure to the signal of video camera transmitters, while the latter are a clearly marked pulse sequence.

To detect "radio bookmark" signals, it is necessary to move the antenna of the ST 033 "Piranha" product around the monitor and the system unit, fixing the level of the received signal and the frequency meter readings. The presence of a "radio bookmark" in the PC and its operation for transmission correspond to a sharp increase in the level of the received signal and a relatively high frequency stability. In this case, you should fix the position of the antenna, which corresponds to the maximum level, turn on the "OSC" mode and visually evaluate the type of signal. To eliminate erroneous conclusions, compare it with the oscillogram of side electromagnetic radiation of the PC monitor, the view of which is shown in Figure 9.

Fig. 9 PEMI monitor PC

The determination of the installation location of the "radio bookmark" is carried out, in addition, by sequentially turning on and off the monitor and the system unit.

NOTE: The methodology for searching and locating unauthorized radio stations, radiotelephones, telephones with radio extensions and radio beacons is completely similar to the method for searching and locating radio microphones. Moreover, in the vast majority of cases, one should focus on the amplitude method with periodic listening to the demodulated signal in the "AUD" mode.

2. Using the product to detect information leakage channels through wire lines for various purposes

Here we consider methods for identifying artificially created channels of information leakage through wired lines, which are based on the use of special technical means. The main types of wire lines, for the analysis of which the product ST 033 "Piranha" is intended, are power lines (high-potential lines), as well as subscriber telephone lines and lines of fire and security alarm systems (low-potential lines).

In general, the techniques and methods used to test the wire lines of these types are the same. Connection to them is carried out using a single, universal adapter. Scanning analyzes the overall range from 0 to 15 MHz. The output of the scan results is made in the form of a panorama image with the same type of representation (display) of the measured parameters. The functions of the product controls are the same (regardless of the type of line being tested).

The general (for all lines) provisions of the operating procedure are as follows.

The preparation of the controlled premises consists in checking the compliance of the number and purpose of the wire lines actually existing in it with the previously made (presented) schemes for their laying.

The preparation of the ST 033 "Piranha" product itself (after checking its performance in this mode) actually consists only in choosing the most convenient tips for the probes, in relation to the type and features of the existing wire lines.

The greatest attention should be paid to the range of 40-2500 kHz, as the most typical for use by bugs powered by the voltage of wire lines and transmitting intercepted information through their wires. Embedded devices with frequencies of about 7 MHz and higher are much less common. To ensure the guaranteed reliability of not skipping bug signals in frequency, the upper limit of the scanning range into the ST 033 "Piranha" product is defined at the level of 15 MHz.

Turn on the product.

Wait for the start of scanning in the range up to 10.450 MHz and after completion of 2-3 cycles, set the upper limit of the range at the level of 15 MHz. Having carefully studied the most characteristic features of the panorama image, determine the presence of frequency components that exceed the level of the general background.

If necessary, divide the range into separate intervals and scan them in detail, stopping, first of all, at the frequencies of the most intense components.

The boundaries of the intervals are set by successively pressing the "SET", "4" buttons, the buttons with digital markings and the "ENTER" button (or an alternative option with setting the center frequency and bandwidth).

Set the lower threshold for signal level indication to about 10-15%. To do this, press the "SET" button, use the "3" button to display the inscription "3 -> THRESHOLD level", press the "ENTER" button and use the "5" and "6" buttons to set this indication threshold. Subsequently, depending on the nature of the panorama image, choose the most convenient threshold level for analysis.

Scanning is started and stopped by pressing the "RUN/STOP" button.

After passing through several scan cycles, you can reasonably set the "auto-stop" threshold, for which press the "SET" button, select the "SQUELCH LEVEL" mode with the "3" button, confirm the selection with the "ENTER" button and, by manipulating the "5" and "6" buttons, set cursor to the required level. After stopping at the frequency of one or another signal, you should fine-tune using the "3" and "4" buttons, while analyzing the signal "by ear" by turning on the "AM" and "FM" detectors in turn using the "ENTER" button. To analyze weak signals, you can use the "SET", "5" and "ENTER" buttons to select a more convenient amplitude range (0.1-1mV).

If necessary, supplement the capabilities of signal analysis in wired lines by switching the product to the "OSC" and "SA" modes, since the images of oscillograms and spectrograms of signals displayed on the display screen provide a more detailed description of the parameters. This can be verified by comparing the images of the panorama and the oscillogram of the same digital signal for the transmission of speech information (see Fig. 10 and Fig. 11).

NOTE.

If the room is included in the plan of regular periodic inspections, then it is advisable to save a panorama (oscillogram, spectrogram) of the necessary frequency intervals in non-volatile memory.

To save, press the "SAVE" and "ENTER" buttons. To recall the desired panorama (oscillograms, spectrograms) from memory, press the "LOAD" button.
At the same time, it is necessary to take into account some features determined by the specifics of the lines of each type.

It is advisable to start checking the presence in the electrical network of special technical means that receive acoustic signals from the room, are powered by the network and transmit information at a high frequency through its wires, it is advisable to start with network outlets. To reduce the background level, turn off (with a visible disconnection from the sockets) all electrical appliances and equipment located in the controlled room.

Connect the product to the network using any of the sockets for this (as a rule, the energy supply of the room is carried out from one phase or at least from one switchboard).

Analyze the panorama image.

If a signal is detected that contains signs of modulation by the acoustics of the room, then the method of "acoustic tie-in" can be used to localize its source, by connecting in turn to all the outlets in the room being checked.

A similar check should be carried out on the elements of the lines supplying electric lighting devices.

After checking the power lines and lines supplying lighting fixtures, it is necessary to check tees, extension cords and other power-consuming devices by connecting them to the mains in turn.

Checking wired lines of fire and security alarm systems, as well as lines of unknown purpose, is similar to checking power lines, since the technical means used on these communications are similar.

When checking subscriber telephone lines, in addition to searching for the special technical means described above, it is necessary to solve the problem of identifying the fact that the line is used to obtain acoustic information from the premises due to linear high-frequency imposition. A sign of the fact of linear high-frequency imposition is the presence of an unmodulated stable probing signal in the line at frequencies not lower than 150 kHz. At the same time, the procedure for connecting the product and the analysis procedure does not differ from that stated in relation to checking power lines.

3. Using ST 033 to identify channels of information leakage in the infrared range

In principle, two types of such information leakage channels should be considered. One of them is created through the use of special technical means with the transmission of intercepted information in the infrared range. Another channel is based on the irradiation of glass window openings by a directed beam of an infrared radiation source and the reception of a reflected signal modulated by the acoustics of the room.

To identify both channels of leakage, it is necessary to carry out the same preparatory measures. First of all, you should choose the right time for the test, namely, when direct sunlight does not enter the windows of the controlled room. In the room itself, it is necessary to turn off incandescent lamps and sources of intense heat radiation. It is also advisable to turn off the color TV, if available, as the product's sensor may react to "warm" picture tones.

The specificity of infrared bookmarks predetermines the need to provide "line of sight" between the transmitter of the bookmark and the receiver of infrared radiation. Therefore, indoors, the transmitter radiation path to the outside can only pass through window openings. Taking into account these features, the search for dangerous signals should start from the windows of the room, moving deeper into it. Since the transmitter can have a fairly narrow radiation pattern, and the angle of view of the product sensor is 300, it is necessary to smoothly change the spatial orientation of the sensor. A sign of the presence of infrared radiation is the appearance of colored segments of the level indicator scale and clicks of sound indication in the "TONE" mode after coloring the 4th element of the scale. The detected signals can be analyzed "by ear" in the "AUD" mode, as well as visually using the built-in oscilloscope and spectrum analyzer. The localization of sources of infrared radiation is most accurately carried out by a combination of the amplitude method and the method of "acoustic binding". In this case, the procedure is the same as when working in the high-frequency detector-frequency meter mode.

To identify external potentially dangerous infrared radiation, it is necessary to examine each window opening. In this case, the sensor is oriented towards the window. Smoothly changing its spatial position, conduct a survey of the entire area of ​​the window opening. Since the probing signal has no modulation, its presence can only be assessed by readings of the level indicator and tone indication in the "TONE" mode.

4. Using ST 033 to identify channels of information leakage through low-frequency magnetic fields

Such channels are characterized by the fact that they arise when authorized means are used for their intended purpose (PC, intercoms, sound amplification systems, tape recorders, telephones, etc.). Therefore, one of the main tasks should be considered the study of such means for the presence, intensity and range of a low-frequency magnetic field. The tasks of searching for hidden (unauthorized) wiring and detecting working voice recorders can be considered related tasks.

Before carrying out work, it is advisable to turn off the fluorescent lamps in the room, and, if necessary, turn on the antenna of the product in differential mode (set the switch on the antenna housing to the position "toward the white point").

Potential sources of dangerous low-frequency magnetic fields should be checked separately, turning them on one by one.

In the study of technical means, it is necessary to evaluate the range of propagation of magnetic fields and the features of their spectrum. To do this, initially place the magnetic antenna in close proximity to the object under study. Fix the relative level of the field on the oscillogram. Moving away from the investigated means and changing the spatial orientation of the antenna, estimate the range of reliable reception of the low-frequency signal.

With regard to audio frequency amplifiers with an output transformer, it is necessary to estimate the range of confident (intelligible) reception of a speech (test) signal.

Such an assessment can serve as the basis for the correct choice of installation locations for the appropriate means in relation to the outside of the room and the option of their joint location in the room. If necessary, turn on the "SA" mode, analyze the spectrogram and write it to non-volatile memory.

To search for hidden wiring, it is necessary to sequentially go around all the walls of the room, placing the magnetic antenna in close proximity to them. Fix the area of ​​increasing field level and, by moving the antenna horizontally and vertically, determine the passage of the concealed wiring route.

The possibility of detecting working voice recorders is determined both by the level of the magnetic field created by their motors and by the level of the magnetic background of the room. To solve this problem, specialized tools are usually used with preliminary thorough preparation of the premises. Therefore, it is not always possible to achieve a positive result only when using the product ST 033 "Piranha", especially at a distance of 30 cm or more between the recorder and the magnetic antenna.

5. Using ST-033 to evaluate the effectiveness of vibroacoustic protection and soundproofing of premises

The combination of these areas of use of the product is determined by the commonality of sources of information leakage channels (speech signal in the acoustic range), the similarity of control methods and the practical identity of using the capabilities of ST 033 "Piranha".

Firstly, in both cases, when preparing the room, it is necessary to turn off the devices and means that create an additional acoustic background.

Secondly, in both cases, test, and best of all calibrated, sound signal sources should be used.

Thirdly, in adjacent, in relation to the checked, premises, the minimum possible level of acoustic background should be provided.

Fourthly, almost the same methods of signal analysis are used ("by ear", according to oscillograms and spectrograms).

Evaluation of the effectiveness of vibroacoustic protection of a room is usually carried out in two stages. At the first stage, the protection, if any, should be turned off and the actual vibroacoustic properties of the surfaces enclosing the room should be checked. To do this, it is necessary to attach a vibroacoustic sensor in various places of the surfaces being checked (walls, doors, windows, if possible, the floor and ceiling) from the outside, in relation to the controlled room, side.

Turn on the test sound source. It can be placed either in the usual place for conducting confidential conversations, or at a certain distance from the examined surface (for example, as shown in Figure 12).

Fig.12. A variant of the scheme for assessing vibroacoustic
properties and vibroacoustic protection of premises.

The sound level is usually set to correspond to loud speech (74 dB). For calibrated sound sources, the distance "L" is chosen in the range of 1.0-2.0 m. First, at a qualitative level (by direct listening), the vibroacoustic properties of the examined surfaces are evaluated, and then, by switching to the "SA" mode, the amplitudes of the frequency components of the test signal are quantitatively evaluated.

At the second stage, if it is provided, the effectiveness of the vibroacoustic protection system is evaluated. To do this, on each surface, both qualitatively "by ear" and quantitatively according to the spectrogram, the ratio of the levels of the test and masking signal is determined, and "uncovered" components of the spectrum are also revealed. This serves as an objective basis for correcting the amplitude-frequency characteristics of the masking signal sources.

According to generally accepted rules, the intelligibility of speech signals is guaranteed not to be restored if the masking noise (interference) is 4-5 times (16dB) higher than their level. The complete exclusion of speech signs is achieved when the signal level is exceeded by 8 times by the interference created by the active protection system.

It is also expedient to carry out assessment of sound insulation of premises in two stages.

At the first stage, using a test signal source with a sound level corresponding to loud speech, establish a correspondence between this level and the readings of the ST 033 product in the oscilloscope and spectrum analyzer modes. To do this (see Figure 13), place the acoustic emitter of the sound source and the microphone of the ST 033 product at a certain fixed distance. Usually it is chosen within 1.0-2.0 m.

Fig.13. Variant of indicator calibration scheme
the sound level of the ST 033 product.

At the second stage, the soundproofing properties of the surfaces enclosing the room (walls, doors, windows, and if possible, the floor and ceiling), the effectiveness of the active protection system (noise), as well as the possibility of leakage of speech acoustic information through ventilation elements, various kinds of niches, through holes etc.

To assess the soundproofing properties of walls, doors (floor, ceiling), the test sound source can be located either in the usual place for conducting confidential conversations, or at a distance from the surface being examined. For example, in the version shown in Figure 14.

Fig.14. Room soundproofing assessment.

By placing a microphone in different places of adjacent (above and below) rooms, qualitatively "by ear" and quantitatively using a spectrogram, determine the range of interception of speech information from a given room and evaluate the decrease in the level of the sound signal due to the properties of the enclosing surfaces, as well as the presence of the least attenuated components of the spectrum. The latter makes it possible to make an informed decision on the need for additional protection, including active protection, and the choice of characteristics of protective equipment.

If the room is located above the first floor, there are certain difficulties in checking the sound insulation of window structures. In this case, the effect that is sufficient for a qualitative assessment is given by the following frequently used technique. The test sound source is placed according to any of the previously considered options. A vent, transom or other part of the window opens, depending on the features of the window sashes. The microphone is hung out and in this position the level of the test signal received by it from the room is fixed. Then the open part of the window is carefully (so as not to damage the microphone cable), but, if possible, tightly covered. Qualitatively "by ear" and quantitatively according to the oscillogram or spectrogram, the sound-proof properties of window structures are evaluated.

Since the air ducts of ventilation systems are considered to be the most dangerous channels for the leakage of speech acoustic information, they are subject to mandatory verification. To do this, the microphone of the ST 033 device must be inserted into the outlet (inlet) of the air duct of each of the adjacent rooms, and possibly some others. Qualitatively "by ear" evaluate the transmission and intelligibility of the signal from the test source, and according to the readings of the ST 033 device in the oscilloscope or spectrum analyzer mode, its attenuation when passing through the air duct to the location of the microphone. In this case, a correct assessment of the attenuation can only be obtained if a detailed diagram of the ventilation system is available. Its presence makes it possible to take into account the weakening introduced by various structural elements of the air ducts. So, the attenuation of the speech signal is usually:

Broadband amplifiers are an integral part of many radio engineering systems and devices. In some cases, among others, they are required to match with a standard 50- or 75-ohm path. One of the most successful circuit solutions for constructing such

amplifiers is the use of cross feedback (L1, L2, L3), providing input and output matching, a constant value of the upper cut-off frequency with an increase in the number of amplifier stages and high repeatability of their characteristics. In addition, cross-feedback amplifiers require little or no tuning.

Amplifier Specifications:

1. Operating frequency band .. 0.5-70 MHz.
2. Output voltage, not less... 1 V.
3. Gain ..... 20 ± 1 dB.
4. Input/output impedance.. 50 Ohm.
5. Current consumption........ 120mA.
6. Supply voltage..........12V.
7. VSWR at the input, no more than ......... 1.5.
8. Output VSWR, not more than.........3.
9. Overall dimensions..... 70x45 mm.

circuit diagram

On fig. 1 shows a schematic diagram of an amplifier with cross-feedback, in which the output stage is implemented according to the Darlington circuit, that is, series-parallel switching of transistors is used, which allows increasing the output voltage level (L.4). On fig.

2 shows a drawing of a printed circuit board.

The amplifier contains two preliminary stages on transistors ME1 and ME2 and an output stage on transistors ME3 and ME4, connected according to the Darlington circuit.

All amplifier stages operate in class A mode with current consumption of 27 mA, which are set by selecting the values ​​​​of resistors R1, R5, R9, R13. Resistors R3, R7, R10, R14 are local feedback resistors. Resistors R4, R8, R12 are common feedback resistors.

Rice. 1. Schematic diagram of a broadband RF amplifier.

A printed circuit board (Fig. 2) with a size of 70x45 mm is made of fiberglass with a thickness of 2 ... 3 mm foiled on both sides. Dotted lines in fig.

2 marked the places of metallization of the ends, which can be done using metal foil, which is soldered to the bottom and top of the board.

Fig.2. RF amplifier circuit board.

Setting up the amplifier consists of the following steps. First, with the help of resistors R1, R5, R9, R13, the quiescent currents of the amplifier transistors are set. Then, by varying the value of the resistor R4 within small limits, the voltage standing wave ratio at the amplifier input is minimized.

The voltage standing wave ratio at the amplifier output is minimized by resistor R12. By changing the value of the resistor R8, the bandwidth and gain of the amplifier are adjusted.

If necessary, the upper cutoff frequency of the amplifier can be increased. To do this, replace the KT315G transistors with higher-frequency ones. In this case, for the circuit shown in Fig.

1, the upper limiting frequency will be about 0.25 ... 0.3 Ft, where Ft is the limiting frequency of the current transfer coefficient of the base of the transistor (L.5). The use of the circuit design under consideration makes it possible to create amplifiers with an upper cut-off frequency up to 2 GHz (L.2). When constructing them, it should be taken into account that the general feedback circuits, consisting of elements C4, R4; C6, R8; C7, R12, should be as short as possible.

This is due to the need to eliminate excessive phase delay of the signal in these circuits. Otherwise, the amplitude-frequency characteristic of the amplifier in the high-frequency region turns out to be up. With a significant elongation of these circuits, self-excitation of the amplifier is possible.

Titov A. Rk2005, 1.

Literature:

1. Titov A. A. Simplified calculation of a broadband amplifier. Radio engineering, 1979, No. 6, p. 88-90.
2. Avdochenko B.I., Dyachko A.N. and others. Ultrawideband amplifiers on bipolar transistors. Communication technology. Ser. Radio measuring equipment, 1985, Vil. 3, p. 57-60.
3. Abramov F.G., Volkov Yu.A. et al. Matched broadband amplifier. Instruments and technique of experiment. 1984. No. 2, p. 111-112.
4. Titov A.A., Ilyushchenko V.N. Broadband amplifier. Utility model patent No. 35491 Ros. patent and trademark agencies. Published 01/10/2004 Bull. 1.
5. Petukhov V.M. Transistors and their foreign analogues: A reference book in 4 volumes.