joenc project rport

1SMART MOBILE JAMMER

CONTENTS

Abstract………………………………………………………………………………

Introduction………………………………………………………………………….

Block diagram description…………………………………………………………...

Working of the circuit………………………………………………………………..

Circuit description…………………………………………………………………...

Circuit diagram………………………………………………………………………

Product design……………………………………………………………………….

PCB design and layout………………………………………………………………

Product feature……………………………………………………………………….

Result and conclusion………………………………………………………………..

Component list and bill of materials………………………………………………...

Bibliography…………………………………………………………………………

Appendix…………………………………………………………………………….


ABSTRACT

GSM JAMMER

GSM jammer is a product which jams cell phone activity in a region. Such mobile jammer circuits have become a necessity for accomplishing a more cultural society as there is a growing demand for controlling the use of mobile phones in various public places such as religious places, libraries, theatres and others.


The last few years have witnessed a dramatic boom in the wireless communications industry hence increasing the number of users of mobile communication devices. This has magnified the need for a more efficient and reliable jammer

The product is becoming more and more socially relevant due to the wide features that today mobile phones are loaded with. The cell phone can be used as cameras, surveillance device, etc, unnoticeably; various incident of abuse of various features that these smart phones provide have been reported. This shows the need for a ‘smart jammer’.

The design of smart jammer has been conceived keeping in mind the issues of cost, durability and health. The design has tried to reduce the total output power to adhere with the recommendations of many medical societies and other societies regarding the reduction of electromagnetic radiations in atmosphere

Now, one can enjoy a movie in a theatre or read a book in peace in library, thanks to SMART JAMMER.

INTRODUCTION

A GSM jammer is a device that transmits signal on the same frequency at which the GSM system operates. When the mobile phones are disabled jamming is successful. Communication jamming devices were first developed and used by military. This interest comes from the fundamental objective of denying the successful transport of information from the centre (tactical commanders) to the receiver(army personnel), and vice versa.


The technology behind cell phone jamming is very simple. The jamming device broadcast an RF signal in the frequency range reserved for the cell phones that interferes with the cell phone signal, which results in a no network available display on the cell phone screen. All phones within the effective radius of the jammer are silences. It should be mentioned that cell phone jammers are illegal devices in most countries. According to Federal Communications Commission (FCC) in USA: “The manufacture, importation, sale, or offer for sale, of devices designed to block or jam wireless transmissions is prohibited”. However, recently there has been an increasing demand for portable cell phone jammers. We should mention that this project, presented in this report, is solely done for educational purposes.

INTENDED MARKET SEGMENT

The wide application of smart jammer can be understood by the wide reach of mobile phone usage

It can be used in public places where mobile phone conversations can become nuisance. These places include worship places, university lecture rooms, libraries, concert halls, meetings rooms, and other places where silence is appreciated

It can be used in situations and locations where sensitive information area being passed

It can be used in schools and colleges where mobile phones are banned. it can be used to prevent the usage of mobile phones as surveillance device It can be used in aero planes to prevent the interference of the signals with the

cockpit signals.

.

JAMMING TECHNIQUES

There are several ways to jam an RF device. The three most common techniques can be categorized as follows

SPOOFINGIn this kind of jamming, the device forces the mobile to turn off itself. This type is very difficult to be implemented since the jamming device first detects any mobile phone in a specific area, then the device sends the signal to disable the mobile phone. Some types of this technique can detect if a nearby mobile


phone is there and sends a message to tell the user to switch the phone to the silent mode (intelligent beacon disablers).

SHIELDING ATTACKSThis is knows as TEMPEST or EMF shielding. This kind requires closing an area in a faraday cage so that any device inside this cage cannot transmit or receive RF signal from outside of the cage. This area can be as large as building, for example.

DENIAL OF SERVICEThis technique is referred to DOS. In this technique, the device transmits a noise signal at the same operating frequency of the mobile phone in order to decrease the signal-to-noise ratio (SNR) of the mobile under its minimum value. This kind of jamming technique is the simplest one since the device is always on. Our device is of this type.


BLOCK DIAGRAM DESCRIPTION

Triangle wave generator


Noise generator Mixer clamper vco

Power

Amplifier

RF output, antenna

section

NOISE GENERATORThe noise generator is just a standard 6.8 volt zener diode with a small reverse current and a transistor buffer. It has to act as a natural; band pass filter and small signal amplifier. The noise jamming signal is then mixed with the triangle wave input. This will help in masking the jamming transmission. Making it look like random “noise” to an outside observer. Without the noise generator the jamming signal is just a sweeping, unmodulated continuous wave (CW) RF carrier.

MixerThe opamp is configured as a summing amplifier (gain =1), otherwise knows as a mixer. The output of a summing amplifier is the sum of the input voltages. The input to this mixer is a triangle wave and a random noise signal. These signals are mixed to form a new “noisy” triangle waveform. When applied to the VCO, resulting RF signal will “sweep” across the cellular downlink frequencies, and will be frequency modulated with the noise signal. The noise modulation helps to increase the jammer’s effectiveness

Clamper

Input of the vco must be bounded from 0 to 3.5v to get the needed frequency range. So, we need to add a clamper to get our goal.

Voltage controlled oscillator


The vco’s output frequency changes in accordance with the input voltage. The VCO chosen should cover the frequency range of the cellular base station’s down linking frequencies(lower transmit) you wish to jam. You always jam a receiver, so in this case, you would jam the mobile station’s(handset) receive frequencies which are the cellular tower’s transmit frequencies.

Amplifier and transmitter sectionThe preamplifier stage provides the necessary gain to drive the circuit. It isolates the main circuit from the amplifier stage, gives impedance matching to transfer maximum power and provides low input impedance and high output impedance. It lowers distortion and noise and also prevents loading.The power amplifier stage amplifies the signal from the pre amplifier stage. It is the main amplifier with very large gain in the transmitter section of the jammer. The power transmitter used is a high frequency transistor.


WORKING OF THE CIRCUIT


HOW A CELLULAR TELEPHONE CALL IS MADE?

When a cellular phone is turned on but is not yet engaged in a call, it first scans the group of forward control channels to determine the ones with the strongest signal and then monitors that control channel until the signal drops below a usable level. At this point it again scans the control channel in search of the strongest base station signal. For each cellular system the control channels are defined and standardized over the entire geographic area covered. So every phone scans the same channels when ideal.

When a telephonic call is placed to a mobile user. The mobile switching unit dispatches the requests to all base stations in the cellular system. The mobile identification number which is the subscribers telephone number is then transmitted as a packing message over the entire forward control channel throughout the cellular system. The mobile receives the paging message sent by the base station, it monitors and responds by identifying it over the reverse control channel. The base station relays the acknowledgement sent by the mobile and informs MSC of the handshake. Then, the MSC instructs the Base Station to move the call to an unused voice channel within the cell. At this point the base station asks the mobile to change frequencies to an unused forward and reverse voice channel pair , at which point another data message called an alert is transmitted over the forward voice channel to instruct the mobile to ring.

HOW JAMMER WORKS

The jammer transmits signals in the standard frequency channel used by the cell phones, so when a call is originated and the handset searches for the strongest signal it gets locked onto the frequency transmitted by the jammer and so the call cannot be completed, that is it disturbs the chain of events described above and prevent the establishment of a speech channel by transmitting noise in the same frequency of the signal performing the control process.


CIRCUIT DESCRIPTION


PARTS OF THE JAMMER DEVICE

Figure shows the block diagram of the jammer to be designed

THE POWER SUPPLY

This is used to supply the other sections of the needed voltages. Any power supply consists of the following

Transformer is used to transform the 220V AC to other levels of voltages

Rectification:- this part is to convert the AC voltage to a DC one. We have two methods for rectifications

Half wave rectification: the output voltage appears only during positive cycles of the input signal

Full wave rectification: a rectified output voltage occurs during both the positive and negative cycles of the input signal

The filter: used to eliminate the fluctuations in the output of the full wave rectifier “eliminate the noise” so that a constant DC voltage is produced. This filter is just a large capacitor used to minimize the ripple in the output

Regulator: this is used to provide a desired DC voltage

The IF section


The tuning section of the jammer sweeps the VCO through the desired range of frequencies. Basically, it is just a triangle or sawtooth-wave generator; offset at a proper amount so as to sweep the VCO from the minimum desired frequency to a maximum. The tuning signal is generated by a triangular wave mixed with noise. The IF section consists of three main parts:

Triangle wave generator. (To tune the VCO in the RF section)

Noise generator (provides the output noise).

Mixer” summer” (to mix the triangle and the noise waves).

TRIANGLE WAVE GENERATOR

The main use of the triangle wave is to sweep the VCO through the desired frequency range. We want to cover the downlink through our VCO, i.e.,935-960 MHz for VCO66CL, and 1805-1880MHz for VCO55BE.

In our design, we will use 555timer IC operating in the a-stable mode to generate the sweeping signal. The output frequency depends on the charging and discharging of the capacitor, resistors values and the power supply for the IC. Figure 3 shows how we can use the 555timer in the general A-stable mode


The charging time for the capacitor can be found as follows:

For discharging time, the following equation can be used:

The output frequency can be calculated as follows:

In our project, we need to get the duty cycle (D.C.) equal to 50%

which means the time needed for charging equals the discharging time.

This can be done by using Ra=Rb and placing a diode across Rb. The

following equation shows the output frequency:

Figure 4 shows the connection for the A-stable mode with D.C.=50%.


In our project, we used Ra=Rb=750 Ω with C=0.1 µF, then the output frequency is 10 KHz Since we use +12 V (Vcc), the output signal will be bounded from 4 V (Vcc/3) to 8 V (2Vcc/3). Figure 5 shows all the components used to generate the triangular wave. The output

Noise generation

Without noise, the output of the VCO is just an un-modulated sweeping RF carrier. So, we need to mix the triangular signal with noise (FM modulating the RF carrier with noise). To generate noise signal, we used the Zener Diode operated in reverse mode. Operating in the reverse mode causes what is called avalanche effect, which causes wide band noise. This noise is then amplified and used in our system. We use two amplification stages: in the first stage, we use NPN transistor as common emitter, and in the second stage, we use the LM386IC Audio amplifier. This is shown in Figure 7. The output of this section is clearly seen in

Mixer


The mixer here is just an amplifier that operates as a summer. So, the noise and triangular wave will add together before entering the VCO. The LM741 IC was used to achieve this.

Using Rnoise =1 KΩ, we amplify the noise signal by 2. In this case, the ratio of the noise to the sweep signal is 2:1.

Clamper

The input of the VCO must be bounded from 0 to 3.5 V to get the needed frequency range. So, we need to add a clamper to get our goal. The clamper consists of a capacitor connected in series with a resistor and diode, as shown in Figure 10.


The whole IF section is shown below


4.2.3 The RF-Section

This is the most important part of the jammer, since the output of this section will be

interfacing with the mobile. The RF-section consists of three main parts: voltage controlled

oscillator VCO, power amplifier and antenna.

The voltage controlled oscillator (VCO) is the heart of the RF-section. It is the device that

generates the RF signal which will interfere with the cell phone. The output of the VCO has a

frequency which is proportional to the input voltage, thus, we can control the output

frequency by changing the input voltage. When the input voltage is DC, the output is a

specific frequency, while if the input is a triangular waveform, the output will span a specific

frequency range. In our design, we need to find a VCO for GSM 900 and GSM 1800. There

are three selection criteria for selecting a VCO for this application. Most importantly, it

should cover the bands that we need, secondly, it should be readily available at low cost, and

finally, it should run at low power consumption. Moreover, we need to minimize the size of

GSM-jammer. So, we started to search through the internet for VCO's that work for GSM

900 & GSM 1800 bands.

Finally, we found the following VCO IC

.

CVCO55CL; this is for GSM 900. The output frequency is 925-970 MHz and the output

power is up to 8 dBm.

We chose these IC’s for the following reasons:-

[A] Surface mount, which reduces the size of product.

[B] Having large output power that reduces the number of amplification stages that we need.

[C] Having same value of power supply which is typically equal to 5 volt.

[D] Having same noise properties.


The power amplifier: Since 5 dBm output power from the VCO does not achieve the desired

output power of the GSM jammer, we had to add an amplifier with a suitable gain to increase

the VCO output to 34 dBm. We obtained our amplifier IC (PF08109B ) from an old mobile

as it was the most suitable, cheapest and easiest way to get one.

The PF08109B, shown in Figure 15, has high gain of 35 dB. As datasheets illustrated that this

IC is designed to work in dual band GSM & DCS, we firstly designed and built our circuit

using only one power amplifier IC. Upon testing, the jammer didn’t work properly. It was

concluded that amplifier IC does not work at the two bands simultaneously. Such a fact was

not indicated in the datasheets. This result was really a big shock, but easily solved by

changing the whole RF design. The new design uses two power amplifier IC’s instead of one

amplifier. Figure 16 shows the two designs for the RF-Section.

Antenna: A proper antenna is necessary to transmit the jamming signal. In order to have

optimal power transfer, the antenna system must be matched to the transmission system. In

this project, we used two 1/4 wavelength monopole antennas, with 50 Ω input impedance so

that the antennas are matched to the system. We used monopole antenna since the radiation

pattern is omni-directional. Figure 17 shows the DCS 1800 antenna, while Figure 18 shows

the GSM 900 antenna.

Figure 20 RF-section Schematic.


CIRCUIT DIAGRAM


PCB FABRICATION

PCB fabrication is an important step in the manufacturing process of the circuit. The various steps involved in the PCB fabrication are

1. Preparation of layer of the track


2. Transferring the layout on to the copper3. Etching to remove the copper from copper clad wherever it is not required4. Drilling holes for the component mounting

Preparation of layout

The track layout of the electronic circuit must be drawn on a white paper. The layout should be made in such a way that the parts are in easy routes. This enables the PCB more compact and economical

Transferring the layout on to the copper

The layout made on the white paper should be redrawn on the copper clad using paint or nail varnish

Etching

Ferric chloride solution is properly used as etching solution. The ferric chloride powder is made into a solution using water and kept in a plastic tray. Immerse the marked copper clad in this solution for two hours. Due to the reaction, solution becomes weak and it is not recommended for etching purpose. The copper in the unmarked area will be etched out. Take out the etched sheet from the tray and fry it out in sunlight for an hour, later remove the paint or nail varnish turpentine

Drilling

The holes are made by drilling machine for the component insertion

Soldering

Soldering is the process of joining two or more similar metals by melting another metal having low melting point.

In order to make solder accept the solder readily, the component terminals must be free from oxides and other obstructing films. Soldering flux cleans the oxides from the surface of the metal. The leads are cleaned chemically or by scrapping using a blade or a knife, small amount of lead is coated on the leaned portion of the lead and the bit of the soldering iron.

Solder is used for joining two or more metals below their melting point; the solder used is an alloy of tin and lead. Soldering iron is used to melt the solder and apply at the joints in the circuit. It operates at 230 v supply


PRODUCT FEATURE

FUTURE PROSPECTS FOR THE PROJECT

By using VCO IC’s which cover other frequency ranges the project can be used to jam all service providers in GSM and CDMA.

Reducing power consumption

For this we have to detect an increase in power level indicating an exchange between mobile station and base station indicating a phone call or a location update and then turn on the jammer

For implementing this we will have to use a mobile sniffer (detector) circuit in addition to the jammer circuit. In order to ensure minimum power consumption and dissipation while maintaining full efficiency of the transformer has to be stopped after ensuring that no speech channel was established.

Increasing range

Using much powerful amplifier IC’s and also high gain Omni directional antenna the range can be increased to a further extent

Mobile sniffer

If a mobile sniffer (detector) is also used along with the jammer we can also find out the person using the cell phone


RESULT AND CONCLUSION


RESULT

The cell phone activity terminator was found to jam service providers.

It jammed both outgoing and incoming calls and also jammed SMS and GPRS activity.

When the jamming occurred the display showing range in the mobile showed nil or displayed “no service” according to the type of handset.

CONCLUSION

The wide spread use of cell phone in every walk of life will surely enhance the need for cell phone jammers. Soon there will be demand for jammers with varous specifications. Laws will have to be passed regarding the usage of jammers. Soon mobile jammers will be as widespread in market as the cell phones themselves.

Component list and bill of materials


Part amount Total Price

Power supply Power Supply

24bin

1 10 JD

Resistor 10 0.5 JD

Capacitor 10 1.5 JD


IF section

555 timer IC 1 0.5 JD

LM741 1 0.5 JD

LM386 1 1.25 JD

Zener Diode 6.8

v

1 0.15 JD

Diode 2 0.3 JD

RF section

PCB COPPER

CLAD 6*9” 2-

SIDE

1 21.36 USD

OSC VCO 925-

970MHz SMD

.5X.5”

1 29.50 USD

OSC VCO 1785-

1900MHz SMD

.5X.5”

1 28.75 USD

PF08109B Power

Amplifier

2 Old mobile

phones


Bibliography


Linear integrated circuits by Roy chowdary Electronic circuits and devices by JB Gupta Crystek.com Google.com Datasheetcatalog.com

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