Cell Jammer Report

7/27/2019 Cell Jammer Report

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A

Project Report on

CELL JAMMER

Submitted in partial fulfillment of the requirement for the award of the degree of

Bachelor of Technology

In

ELECTRONICS & COMMUNICATION ENGINEERING

From

RAJASTHAN TECHNICAL UNIVERSITY, KOTA

Submitted To Submitted By

Mr. Neeraj Jain Yatendra Pradhan (09EMCEC098)

(Project Coordinator) Yogesh Chand Gupta (09EMCEC099)

Dheeraj Sharma (10EMCEC202)

Guided By

Mr. Sachin Jain

Sr. Lecturer (ECE)

DEPARTMENT OF ELECTRONICS & COMMUNICATION

MODERN INSTITUTE OF TECHNOLOGY & RESEARCH CENTRE

ALWAR (RAJ.)

SESSION: 2012-2013


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CERTIFICATE

This is to certify that the project report entitled CELL JAMMER submitted for the award ofDegree of Bachelor of Technology in the Department of Electronics & Communication

Engineering of Modern Institute Of Technology & Research Centre, Alwar, is a record of

authentic work carried out by him under my/our supervision.

The matter embodied in this project report is the original work of the candidate and has not been

submitted for the award of any other degree . It is further certified that he has worked with me/us

for the required period in the Department of Electronics & communication Engineering, Modern

Institute Of Technology & Research Centre, Alwar.

Submitted To Submitted By

Mr. Neeraj Jain Yatendra Pradhan (09EMCEC098)

Project Coordinator (ECE) Yogesh Chand Gupta (09EMCEC099)


Guided ByMr. Sachin Jain

Sr. Lecturer(ECE)


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ACKNOWLEDGEMENT

I take this opportunity to express my profound gratitude and deep regards to my guide Mr. Sachin

Jain for his exemplary guidance, monitoring and constant encouragement throughout the course of

this project.

I also take this opportunity to express a deep sense of gratitude to Mr. Neeraj Jain (Project

Coordinator) for his cordial support, valuable information and guidance, which helped me in

completing this task through various stages.

I am obliged to staff members of for the valuable information provided by them in their respective

fields. I am grateful for their cooperation during the period of my project.

Lastly, I thank almighty, my parents, brother, sisters and friends for their constant encouragement

without which this project would not be possible.

Submitted By

Yatendra Pradhan (09EMCEC098)

Yogesh Chand Gupta (09EMCEC099)



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ABSTRACT

This report presents the design, implementation, and testing of a dual-band cell-phone jammer.

This jammer works at GSM 900 and GSM 1800 simultaneously and thus jams the three well-

known carriers in Jordan (Zain, Orange, and Umniah). This project went through two phases:

Phase one: studying the GSM-system to find the best jamming technique, establishing the system

design and selecting suitable components.

Phase two: buying all the needed components, drawing the overall schematics, fabricating the PCB

layout, assembling the devices, performing some measurements and finally testing the mobile

jammer.

The designed jammer was successful in jamming the three carriers in Jordan as will be shown at

the end of this report.

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 magnified the need

for a more efficient and reliable signal scrambler. This paper deals with the Mobile Jamming

Technology. The concept of jamming technology is studied in a step-by-step approach. The mobile

jammer in the frequency range of 890MHz to 960MHz (GSM) is developed. Its circuit analysis

simulation is performed using Space-spice Software. Antenna simulation is done by using IE3D

software [8]. The jammer circuit is designed with minimum cost and high efficiency. The jammer

jams the signal within five meter effective radius. Index terms Antenna, Jammer, Wide band

frequency.


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TABLE OF CONTENTS

Chapter-1 Introduction 8

1.1Cell Jammer 81.2 Project Objective 13

1.3 Cell Phone Jamming Device 13

1.4 Jamming Basics 15

1.5 Inside A Cell-Phone Jammer 17

1.6 Jamming Technique 18

1.7 System Concept 19

1.8 Block Diagram of Cell Jammer 20

Chapter-2 Design Parameter 21-25

Circuit Diagram of Cell Jammer 22

2.1 System Design 23-25

Chapter-3 Mobile Jammer 26-32

3.1 Definition of Mobile Jammer 26

3.2 Introduction of Mobile Jammer 27-28

3.3 Mobile Jamming Technique 29-31

3.4 Operation 32

Chapter-4 Cell Jammer Requiring Components 33-41

4.1 Noise Generation 33

4.2 Mixer 34

4.3 Clamper 35

4.4 The Rf-Section 36-37
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4.5 Antenna 38-40

4.6 Circuitry 41

4.7 Power Supply 41

Chapter-5 Used Of Cell-Phone Jammers 42-44

5.1 Legal Issues 43

5.2 Alternatives to Jamming 44

Chapter-6 AAddvvaannttaaggeess && DDiissaaddvvaannttaaggeess 4455

11..22AAddvvaannttaaggeess 445511..33

DDiissaaddvvaannttaaggeess 4455

CChhaapptteerr--77Applications 46

7.1 Cell Phone Jammer Applications 46

Chapter-8 Result & Future Developments 47-48

8.1 Result 47

8.2 Future Developments 48

Conclusion 49-50

References 51

Appendix 52


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LIST OF FIGURES

Fig. No. Fig. Name Page No.

Fig. 1.1 Cell Jammer 8

Fig. 1.2 Jammers Types 10

Fig. 1.3 Continuous Jamming Signal 11

Fig. 1.4 Cell Phone Jammer Device 13

Fig. 1.5 Jamming Basic Work 16

Fig, 1.6 Block Diagram of Cell Jammer 20

fig. 2.1 Circuit Diagram of Cell Jammer 22

Fig. 2.2 Jammer Main Blocks 23

Fig. 2.3 Parts of the Power Supply 24

Fig. 2.4 Astable 555 Timer 25

Fig. 3.1 Mobile Jammer Plat 26

Fig. 3.2 Mobile Jammer Working 28

Fig. 3.3 Operation of Mobile Jamming 32

Fig. 4.1 The Noise Generation 33

Fig. 4.2 The Generated Noise Signal 33

Fig. 4.3 OP-AMP Summer Circuit 34

Fig. 4.4 Diode Clamper 35

Fig. 4.5 The VCO IC'S 37

Fig. 4.6 DCS Antenna 39

Fig. 4.7 The GSM 900 Antenna 39

Fig. 4.8 Picture of the RF-Section 40

Fig. 4.9 The Jammer Device 40


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CHAPTER-1

INTRODUCTION

1.1 Cell Jammer

Cell phones are everywhere these days. According to the Cellular Telecommunications and

Internet Association, almost 169 million people in the United States had cell-phone service in

January 2004. And cell phones are even more ubiquitous in Europe.

It's great to be able to call anyone at anytime. Unfortunately, restaurants, movie theaters, concerts,

shopping malls and churches all suffer from the spread of cell phones because not all cell-phone

users know when to stop talking. Who hasn't seethed through one side of a conversation about anincredibly personal situation as the talker shares intimate details with his friend as well as everyone

else in the area? While most of us just grumble and move on, some people are actually going to

extremes to retaliate. Cell phones are basically handheld two-way radios. And like any radio, the

signal can be disrupted, or jammed.

Fig. 1.1 Cell Jammer

The main purpose of a cell phone jammer is to jam a cell phone signal in a designated area. Cell

phone jammer is radio frequency equipment which produces a RF signal to beat the cell phone
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frequency and effectively jam the signal which results no service to any type of cell phone such

as CDMA and GSM in the range of 800MHz to 900MHz.

The jammer described here is for 900MHz range. Once the cell phone jammer is operating, all

mobile phones present within the jamming coverage area are blocked and cellular activity in the

immediate surroundings is jammed. Presently, cell phones are regularly used by millions of

people all over the world. Because we can use a cell phone from just about anywhere to talk to

anybody it is one of the greatest inventions for social and business life today.

Even though cell phones have many advantages it eventually arises problems such as their

potential use to invade privacy, contribute to academic cheating, even aid in industrial espionage.

Its great to call anyone at anytime. Unfortunately, restaurants, concerts and temples all suffer

from the spread of cell phones because not all cell phone users know when to stop talking. Who

hasnt seethed through one side of a conversation about an incredibly personal situation as the

talker shares intimate details with his friend as well as everyone else in the area. While most of us

just grumble and move on, some people are actually going to extremes to retaliate. As mentioned

above, these situations will cause a nuisance, to avoid these problems we need to implement

jammers. Disrupting a cell phone is the same as jamming any other type of radio communication.

A cell phone works by communicating with its service network through a cell tower or base

station.

We've all wanted to strangle them before. There's nothing worse than some jerk blabbing away on

their cell phone while you're trying to enjoy a movie, meal at a restaurant, or a nice quiet nap on

the bus/train ride to work. Actually, only hearing only one side of a stupid conversation makes us

pay more attention than normal. Our brain expects information from both sides of a conversation,

and it will try to fill in the blanks. You can try to send the offending mobile blabbermouth a few

evil looks or the old "courtesy cough" but those passive aggressive gestures rarely work.

If you really want to shut down a dopey chatter box, then you'll need to acquire a cell phone

jammer.


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WHAT IS A "JAMMER"?

Cell phone jammers are devices that create a temporary "dead zone" to all cell phone traffic in their

immediate proximity. Jammers are typically used by the police and military to control or disrupt

communication during hostage situations and bomb threats. Traditionally, jammers were large antennas

mounted on trailers that had to be pulled behind a truck. They now come in a variety of shapes and sizes

including models that are about the size of a cell phone.

Fig. 1.2 Jammers Types

USING A JAMMER

Because jammers now come in much smaller sizes, they are very easy to carry around. Portable

personal jammers will fit into the palm of your hand or easily slip into your coat pocket. So the

next time someone on your commuter bus refuses to shut up, you can just reach into your

backpack and turn on a temporary "dead zone" with your jammer. Then get back to some nice

peace and quiet.

RANGE & FREQUENCY

Most jammers only have a range of about 50 to 80 feet and will only effectively jam your

immediate surroundings. Mobile blabbermouths will just think they've hit a dead spot in their cell

phone company's coverage until they leave your jammers immediate vicinity. Stronger jammers

are available to cover larger structures like office buildings, movie theaters and churches. They

look like a miscellaneous metal boxes with wires sticking out and are usually mounted on walls or

ceilings (see image on right).


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Most cell phone jammers come in 2 versions, one for Europe, North Africa and the Gulf states

GSM networks (900 & 1800) and one for the Americas & Canada (800 & 1900 mhz) networks.

Make sure you get the right version for your location.

FOR THE ULTRA PARANOID..

For those die hard jammers out there who don't want to give out a continuous jamming signal that

attracts the FCC, you can link a cell phone jammer with a cell phone detector. This way the

jammer(s) only activate when they detect a cell phone signal. You can also connect this system to

an alarm if you want to be alerted the next time someone is snooping at your weekly Dungeons&

Dragons meeting.

Fig. 1.3 continuous jamming signal

A jamming device transmits on the same radio frequencies as the cell phone, disrupting the

communication between the phone and the cell phone base station in the tower. This is called a

denial of service attack. The jammer denies service of the radio spectrum to the cell phone users

within the range of the jamming device. As with other radio jamming, cell phone jammers block

cell phone use by sending out radio waves along the same frequencies that cellular phones use.

This causes enough interference with the communication between cell phones and towers to render


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the phones unusable. On most retail phones, the network would simply appear out of range. Most

cell phones use different bands to send and receive communications from towers. Jammers can

work by either disrupting phone to tower frequencies or tower to phone frequencies. The jammers

effect can vary widely based on factors such as proximity to towers, indoor and outdoor settings,

presence of buildings and landscape, even temperature and humidity play a role.

The possible application areas of jamming system are:

Prevent industrial espionage where mobile units are used as bugging devices. Counter terrorism threats such as remotely detonated bombs in high risk areas. Eliminate public nuisance in places like movie theaters, restaurants and temples.

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 sender

(tactical commanders) to the receiver (the army personnel), and vice-versa. Nowadays, mobile (or

cell) phones are becoming essential tools in our daily life. Here in Jordan, for example, with a

rather low population (around 5 million), three main cell phone carries are available; namely; Zain,

Orange, and Umniah The first two use the GSM 900 system, while the third uses the GSM 1800

system. Needless to say, the wide use of mobile phones could create some problems as the sound

of ringing becomes annoying or disrupting.

This could happen in some places like conference rooms, law courts, libraries, lecture rooms and

mosques. One way to stop these disrupting ringing is to install a device in such places which will

inhibit the use of mobiles, i.e., make them obsolete. Such a device is known as cell phone jammer

or "GSM jammer", which is basically some kind of electronic countermeasure device. The

technology behind cell phone jamming is very simple. The jamming device broadcasts an RF

signal in the frequency range reserved for 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 silenced. It should be mentioned that cell phone jammers are

illegal devices in most countries. According to the Federal Communications Commission (FCC) in

the USA: "The manufacture, importation, sale, or offer for sale, of devices designed to block or

jam wireless transmissions is prohibited".


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1.2Project ObjectiveThe project involves the design and development of cell phone jammers to block all the cell

phones within the designated area. This device will disrupt cellular communication with respect

to the following:

Operate in the 900MHz band.It has a two meter effective blocking radius

1.3 Cell Phone Jamming Device

Jamming devices overpower the cell phone by transmitting a signal on the same frequency and at a

high enough power that the two signals collide and cancel each other out. Cell phones are designed

to add power if they experience low-level interference, so the jammer must recognize and match

the power increase from the phone.

Fig. 1.4 Cell Phone Jammer Device

Cell phones are full-duplex devices, which means they use two separate frequencies, one for

talking and one for listening simultaneously. Some jammers block only one of the frequencies used
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by cell phones, which has the effect of blocking both. The phone is tricked into thinking there is no

service because it can receive only one of the frequencies.

Less complex devices block only one group of frequencies, while sophisticated jammers can block

several types of networks at once to head off dual-mode or tri-mode phones that automatically

switch among different network types to find an open signal. Some of the high-end devices block

all frequencies at once, and others can be tuned to specific frequencies.

To jam a cell phone, all you need is a device that broadcasts on the correct frequencies. Although

different cellular systems process signals differently, all cell-phone networks use radio signals that

can be interrupted. GSM, used in digital cellular and PCS-based systems, operates in the 900-MHz

and 1800-MHz bands in Europe and Asia and in the 1900-MHz (sometimes referred to as 1.9-

GHz) band in the United States. Jammers can broadcast on any frequency and are effective against

AMPS, CDMA, TDMA, GSM, PCS, DCS, iDEN and Nextel systems. Old-fashioned analog cell

phones and today's digital devices are equally susceptible to jamming.

The actual range of the jammer depends on its power and the local environment, which may

include hills or walls of a building that block the jamming signal. Low-powered jammers block

calls in a range of about 30 feet (9 m). Higher-powered units create a cell-free zone as large as a

football field. Units used by law enforcement can shut down service up to 1 mile (1.6 km) from thedevice.
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1.4 Jamming Basics

Disrupting a cell phone is the same as jamming any other type of radio communication A cell

phone works by communicating with its service network through a cell tower or base station. Cell

towers divide a city into small areas, or cells. As a cell-phone user drives down the street, the

signal is handed from tower to tower.

How It Works

Jamming devices overpower the cell phone by transmitting a signal on the same frequency and at a

high enough power that the two signals collide and cancel each other out. Cell phones are designed

to add power if they experience low-level interference, so the jammer must recognize and match

the power increase from the phone.

Cell phones are full-duplex devices, which means they use two separate frequencies, one for

talking and one for listening simultaneously. Some jammers block only one of the frequencies used

by cell phones, which has the effect of blocking both. The phone is tricked into thinking there is no

service because it can receive only one of the frequencies.

Less complex devices block only one group of frequencies, while sophisticated jammers can block

several types of networks at once to head off dual-mode or tri-mode phones that automaticallyswitch among different network types to find an open signal. Some of the high-end devices block

all frequencies at once, and others can be tuned to specific frequencies.







phones and today's digital devices are equally susceptible to jamming.

The actual range of the jammer depends on its power and the local environment, which may

include hills or walls of a building that block the jamming signal. Low-powered jammers block


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calls in a range of about 30 feet (9 m). Higher-powered units create a cell-free zone as large as a

football field. Units used by law enforcement can shut down service up to 1 mile (1.6 km) from the

device

Fig. 1.5 Jamming Basic Work


communication between the phone and the cell-phone base station in the tower.

It's a called a denial-of-service attack. The jammer denies service of the radio spectrum to the cell-

phone users within range of the jamming device.


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1.5 Inside A Cell-Phone Jammer

Electronically speaking, cell-phone jammers are very basic devices. The simplest just have an

on/off switch and a light that indicates it's on. More complex devices have switches to activate

jamming at different frequencies. Components of a jammer include:

Antenna

Every jamming device has an antenna to send the signal. Some are contained within an electrical

cabinet. On stronger devices, antennas are external to provide longer range and may be tuned for

individual frequencies.

Circuitry

The main electronic components of a jammer are:

Voltage-controlled oscillator - Generates the radio signal that will interfere with the cellphone signal.

Tuning circuit - Controls the frequency at which the jammer broadcasts its signal bysending a particular voltage to the oscillator.

Noise generator - Produces random electronic output in a specified frequency range to jamthe cell-phone network signal (part of the tuning circuit).

RF amplification (gain stage) - Boosts the power of the radio frequency output to highenough levels to jam a signal.

Power supply

Smaller jamming devices are battery operated. Some look like cell phone and use cell-phone

batteries. Stronger devices can be plugged into a standard outlet or wired into a vehicle's electrical

system.


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1.6 JAMMING TECHNIQUE

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

categorized as follows:

1. Spoofing

In 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).

2. Shielding Attacks

This is known 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 buildings, for example.

3. Denial of Service

This technique is referred to DOS. In this technique, the device transmits a noise signal at the sameoperating 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.


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1.7 System Concept

The heart of the system is the RF oscillator .The frequency of the oscillator is 900 MHz. This is

the carrier frequency of the jammer.

This frequency is modulated by the modulating signal given to the base of the transistor and the

modulated output is obtained across the collector terminal. This modulated output is connected to

the antenna, which converts the electric signal into electromagnetic signal and transmits it into

the space.

The receiver, which is the cell phone in our case, receives the transmitted signal and tries to

demodulate the signal. Since this signal is not within the bandwidth of the cell it displays

"Network Busy" on the LCD panel. Since the power of the transmitter is greater than the original

signal transmitted from the cell phone tower the cell phone will not respond to the original signal.

This project effectively jams the cell signals. The heart of the circuit is formed by the MCU,

which is used to generate a square wave.

This signal is fed to the integrator and it is mixed with noise which is generated by the noise

generator in the active mixer. This low level signal is feed to VCO circuit module, which

generates the equal frequency of RF spectrum to be jammed.

The RF signal is then feed into a critical tuned BPF and is feed to amplifier then the amplified

signal is fed to high power RF module for further amplification and terminated to antenna.

Electronically speaking, cell-phone jammers are very basic devices. The simplest just have an

on/off switch and a light that indicates it's on. More complex devices have switches to activate

jamming at different frequencies.


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1.8 Block Diagram

Fig, 1.6 Block Diagram of Cell Jammer


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CHAPTER-2

DESIGN PARAMETER

Based on the above, our device which is related to the DOS technique is transmitting noise on the

same frequencies of the two bands GSM 900 MHz, and GSM 1.8 GHz (known also as DCS 1800

band). We focused on some design parameters to establish the device specifications. These

parameters are as follows:

1. The distance to be jammed (D)

This parameter is very important in our design, since the amount of the output power of the

jammer depends on the area that we need to jam. Later on we will see the relationship between the

output power and the distance D. Our design is established upon D=10 meters for DCS 1800 band

and D=20

2. The frequency bands

Table 1: Operating frequency bands.

UPLINK

(Handset

transmit)

DOWNLINK

(Handset

receive)

USED IN MOBILE NAME

JORDAN

BY:

GSM 900 890-915 MHz 935-960 MHz Zain + Orange

DCS 1800 1710-1785 MHz 1805-1880 MHz Umniah

In our design, the jamming frequency must be the same as the downlink, because it needs lower

power to do jamming than the uplink range and there is no need to jam the base station itself. So,

our frequency design will be as follows:

GSM 900 935-960 MHz

GSM 1800 1805-1880 MHz


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Fig. 2.1 CIRCUIT DIAGRAM OF CELL JAMMER


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2.1 SYSTEM DESIGN

Power calculations

Here, we need to find the power that is needed to be transmitted to jam any cell phone within a

distance of around 10 meters for DCS. From the above considerations, we can find the required

output power from the device, as follows:

Using SNR=9 dB and the maximum power signal for mobile receiver=-15 dBm, gives J=-24 dBm.

But, our goal is to find the output power from the device, so when we add the free space loss to the

amount of power at the mobile receiver we get our target:

Output power=-24dBm+58dB = 34 dBm

Parts of the jammer device

Figure 1 shows the block diagram for the jammer to be designed

Fig.2.2 Jammer Main Blocks.


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The Power Supply

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

the following main parts:

Transformer: - is used to transform the 220VAC to other levels of voltages.

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

rectification:

A] Half wave-rectification: the output voltage appears only during positive cycles of the input

signal.

B] Full waverectification: 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.

Figure shows the general parts of the power supply.

Fig. 2.3 Parts of the power supply.

In our project we need 12, -12, 5 and 3.5 volts. We found that the PC power supply can provide all

the voltages that we need in the jammer, so we bought one.


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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 saw tooth-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:

1. Triangle wave generator. (To tune the VCO in the RF section)2. Noise generator (provides the output noise).3. Mixer summer(to mix the triangle and the noise).Triangle wave generator: The main use of the triangle wave is to the 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 555 Timer 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.

Fig. 2.4 Astable 555 Timer.


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CHAPTER-3

MOBILE JAMMER

3.1 Definition of Mobile Jammer

A GSM Jammer or cell phone jammer is a device that transmit signal on the same frequency at

which the GSM system operates, the jamming success when the mobile phones in the area where

the jammer is located are disabled. Communication jamming devices were first developed and

used by military. Where tactical commanders use RF communications to exercise control of their

forces, an enemy has interest in those communications. This interest comes from the fundamental

area of denying the successful transport of the information from the sender to the receiver.

Nowadays the mobile jammer devices or cell phone jammer software are becoming civilian

products rather than electronic warfare devices, since with the increasing number of the mobile

phone users the need to disable mobile phones in specific places where the ringing of cell phone

would be disruptive has increased.

A portable cell phone jammer featured by universal and handheld design, could blocking worldwide

cell phone networks within 2-5 meters, including GSM900MHz,

GSM1800MHz,GSM850MHz/CDMA800MHz and also 3G networks (UMTS / W-CDMA)

Fig. 3.1 Mobile Jammer Plat
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3.2 Introduction of Mobile Jammer

Jamming devices overpower the cell phone by transmitting a signal on the same frequency as the

cell phone and at a high enough power that the two signals collide and cancel each other out. Cell

phones are designed to add power if they experience low-level interference, so the jammer must

recognize and match the power increase from the phone. Cell phones are full-duplex devices,

which mean they use two separate frequencies, one for talking and one for listening

simultaneously. Some jammers block only one of the frequencies used by cell phones, which has

the effect of blocking both. The phone is tricked into thinking there is no service because it can

receive only one of the frequencies. Less complex devices block only one group of frequencies,

while sophisticated jammers can block several types of networks at once to head off dual-mode or

tri-mode phones that automatically switch among different network types to find an open signal.Some of the high-end devices block all frequencies at once and others can be tuned to specific

frequencies.







phones and today's digital devices are equally susceptible to jamming. Disrupting a cell phone is

the same as jamming any other type of radio communication. A cell phone works by

communicating with its service network through a cell tower or base station. Cell towers divide a

city into small areas, or cells. As a cell phone user drives down the street, the signal is handed from

tower to tower


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Fig. 3.2 Mobile Jammer Working


communication between the phone and the cell-phone base station in the town

It's a called a denial-of-service attack . The jammer denies service of the radio spectrum to the cell-

phone users within range of the jamming device. Older jammers sometimes were Limited to

working on phones using only analog or older digital mobile phone standards. Newer models such

as the double and triple band jammers can block all widely used systems (AMPS, iDEN, GSM,

etc) and are even very effective against newer phones which hop to different frequencies and

systems when interfered with. As the dominant network technology and frequencies used for

mobile phones vary worldwide, some work only in specific regions such as Europe or North

America.

The power of the jammer's effect can vary widely based on factors such as proximity to towers,

indoor and outdoor settings, presence of buildings and landscape, even temperature and humidity

play a role. There are concerns that crudely designed jammers may disrupt the functioning of

medical devices such as pacemakers. However, like cell phones, most of the devices in commonuse operate at low enough power output (


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3.3 MOBILE JAMMING TECHNIQUE

Type "A" Device: JAMMERS:

In this device we overpower cell phone's signal with a stronger signal, This type of device comes

equipped with several independent oscillators transmitting jamming signals' capable of blocking

frequencies used by paging devices as well as those used by cellular/PCS systems' control channels

for call establishment. When active in a designated area, such devices will (by means of RF

interference) prevent all pagers and mobile phones located in that area from receiving and

transmitting calls. This type of device transmits only a jamming signal and has very poor

frequency selectivity, which leads to interference with a larger amount of communication spectrum

than it was originally intended to target. Technologist Jim Mahan said, There are two types. One

is called brute force jamming, which just blocks everything. The problem is, it's like power-

washing the airwaves and it bleeds over into the public broadcast area. The other puts out a small

amount of interference, and you could potentially confine it within a single cell block. You could

use lots of little pockets of small jamming to keep a facility under control.

Type B Device: INTELLIGENT CELLULAR DISABLERS

Unlike jammers, Type B devices do not transmit an interfering signal on the control channels.

The device, when located in a designated quiet' area, functions as a detector'. It has a unique

identification number for communicating with the cellular base station. When a Type B device

detects the presence of a mobile phone in the quiet room; the filtering' (i.e. the prevention of

authorization of call establishment) is done by the software at the base station.

When the base station sends the signaling transmission to a target user, the device after detecting

simultaneously the presence of that signal and the presence of the target user, signals the base

station that the target user is in a quiet' room; therefore, do not establish the communication.Messages can be routed to the user's voicemail box, if the user subscribes to a voice-mail service.

This process of detection and interruption of call establishment is done during the interval

normally reserved for signaling and handshaking. For emergency users', the intelligent detector

device makes provisions for designated users who have emergency status. These users must pre-

register their phone numbers with the service providers. When an incoming call arrives, the


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detector recognizes that number and the call are established for a specified maximum duration, say

two minutes. The emergency users are also allowed to make out going calls. Similarly, the system

is capable of recognizing and allowing all emergency calls routed to 911.

It should be noted that the Type B detector device being an integral part of the cellular/PCS

systems, would need to be provisioned by the cellular/PCS service providers or provisioned by a

third-party working cooperatively with full support of the cellular/PCS service providers.

Type C Device: INTELLIGENT BEACON DISABLERS

Unlike jammers, Type C devices do not transmit an interfering signal on the control channels. The

device, when located in a designated quiet area, functions as a beacon and any compatible terminal

is instructed to disable its ringer or disable its operation, while within the coverage area of the beacon.

Only terminals which have a compatible receiver would respond and this would typically be built on a

separate technology from cellular/PCS, e.g., cordless wireless, paging, ISM, Bluetooth. On leaving the

coverage area of the beacon, the handset must re-enable its normal function. This technology does not

cause interference and does not require any changes to existing PCS/cellular operators. The technology

does require intelligent handsets with a separate receiver for the beacon system from the cellular/PCS

receiver. It will not prevent normal operation for incompatible legacy terminals within a quiet

coverage area, thus effective deployment will be problematic for many years. While general

uninformed users would lose functionality, pre-designated emergency users could be informed of a

bypass terminal key sequence to inhibit response to the beacon. Assuming the beacon system uses a

technology with its own license (or in the license exempt band), no change to the regulations are

needed to deploy such a system. With this system, it would be extremely difficult to police misuse of

the bypass key sequence by users.

Type D Device: DIRECT RECEIVE & TRANSMIT JAMMERS

This jammer behaves like a small, independent and portable base station, which can directly interact

intelligently or unintelligently with the operation of the local mobile phone. The jammer is

predominantly in receiving mode and will intelligently choose to interact and block the cell phone

directly if it is within close proximity of the jammer. This selective jamming technique uses a


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discriminating receiver to target the jamming transmitter. The benefit of such targeting selectivity is

much less electromagnetic pollution in terms of raw power transmitted and frequency spectrum from

the jammer, and therefore much less disruptive to passing traffic. The jam signal would only stay on as

long as the mobile continues to make a link with the base station, otherwise there would be no

jamming transmission the technique forces the link to break or unhook and then it retreats to a

passive receive mode again. This technique could be implemented without cooperation from

PCS/cellular providers, but could negatively impact PCS/cellular system operation. This technique has

an added advantage over Type B in that no added overhead time or effort is spent negotiating with the

cellular network. As well as Type B, this device could discriminate 911 calls and allow for

breakthroughs during emergencies.

Type E Device: EMI SHIELD - PASSIVE JAMMING

This technique is using EMI suppression techniques to make a room into what is called a Faraday cage.

Although labor intensive to construct, the Faraday cage essentially blocks, or greatly attenuates,

virtually all electromagnetic radiation from entering or leaving the cageor in this case a target room.

With current advances in EMI shielding techniques and commercially available products one could

conceivably implement this into the architecture of newly designed buildings for so-called quiet-

conference rooms. Emergency calls would be blocked unless there was a way to receive and decode

the 911transmissions, pass by coax outside the room and re-transmitted. This passive configuration is

currently legal in Canada for any commercial or residential location insofar as DOC Industry Canada is

concerned, however municipal or provincial building code by- laws may or may not allow this type of

construction.


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3.4 Operation

As with otherradio jamming, cell phone jammers block cell phone use by sending out waves along the

same frequencies that cellular phones use.

This causes enough interference with the communication between cell phones and towers to render the

phones unusable. On most retail phones, the network would simply appear out of range. Most cell

phones use different bands to send and receive communications from towers (called full duplexing).

Jammers can work by either disrupting phone to tower frequencies or tower to phone frequencies.

Smaller handheld models block all bands from 800MHz to 1900MHz within a 16-feet range (5

meters).Small devices tend to use the former method, while larger more expensive models may

interfere directly with the tower.

The radius of cell phone jammers can range from a dozen feet for pocket models to kilometers for

more dedicated units. Actually it needs less energy to disrupt signal from tower to mobile phone, than

the signal from mobile phone to the tower (also called base station), because base station is located at

larger distance from the jammer than the mobile phone and that is why the signal from the tower is not

so strong.

Fig. 3.3 Operation of Mobile Jamming
http://en.wikipedia.org/wiki/Radio_jamminghttp://en.wikipedia.org/wiki/Duplex_%28telecommunications%29http://en.wikipedia.org/wiki/Duplex_%28telecommunications%29http://en.wikipedia.org/wiki/Radio_jamming


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CHAPTER-4

CELL JAMMER REQUIRING COMPONENTS

4.1 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 LM386 IC {Audio amplifier}. This is shown

in Figure 7. The output of this section is clearly seen in

Fig. 4.1 The Noise Generation.

Fig. 4.2 The Generated Noise Signal.


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4.2 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.

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, the resulting RF signal will

"sweep" across the cellular downlink frequencies, and will be Frequency Modulated (FM) with the

noise signal. This noise modulation helps to increase the jammers effectiveness.

Another thing op-amp performs is to provide a DC offset for the VCO's voltage tune pin. What

this does is give the triangle wave a positive DC voltage offset to help "center" the triangle wave

within the required frequency range.

Fig. 4.3 OP-AMP Summer Circuit

Using Rnoise

=1 K, we amplify the noise signal by 2. In this case, the ratio of the noise to the

sweep signal is 2:1.


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4.3 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.

Fig. 4.4 Diode clamper.

Then, the sweep signal that will sweep the RF-section is as shown in Figure 11. The tuning signalis highly noisy as seen in Figure 11. The whole IF-Section is seen in Figure 12. The IF-section

schematic is shown in Figure 13

.


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4.4 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 ICs:-

CVCO55BE; this is for GSM 1800. The output frequency is 1785-1900 MHz and the output power

is up to 5 dBm.

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 ICs 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.


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The VCO IC'S

Fig. 4.5 The VCO IC'S

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 didnt 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 ICs instead of one amplifier. Figure 1 5 shows the twodesigns for the RF-Section.


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4.5 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 input impedance so that the antennas are

matched to the system.

We used monopole antenna since the radiation pattern is omni-directional. Figure 16 shows the

DCS 1800 antenna, while Figure 17 shows the GSM 900antenna.

At this point, we have a transmissible signal ready. Now we need to radiate it into our intended area to

produce the desired jamming effect. Antenna designs are pattern and frequency specific. This means

we needed to select the right antenna that matched:

The correct frequency range (935-960MHz). An Omni directional radiation pattern From among the

various antennas available in the market, the antenna used in the project was a Helical antenna, with a

reflection coefficient of -17dB.It should be noted that the smaller the reflection coefficient, the better.

And this value of -17dB is a very good value.

It is important to note that the RF-Section was implemented on FR-4 printed circuit board (PCB) withthickness of 1/32 inches. Also RF layout issues such as good grounding, transmission lines, and vias

was taken into consideration when designing the layout for the RF-Section.

Antenna is used to radiate transmitting frequency and generates RF energy. Every jamming

device has an antenna to send the signal. Antennas are external to provide longer range and may

be tuned for individual frequency. Antenna used is a unidirectional, which radiates signal

uniformly in all direction and converts electrical signal into electromagnetic waves.


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Fig. 4.6 DCS Antenna

Specifications:

Frequency: 1700-1900MHz Input impedance 50 VSWR


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Figure shows the RF-Section. The traces in the RF-section were designed to get 50 impedance

to insure matching between the ICs and the board.

Fig. 4.8 Picture of the RF-Section.

A picture of the whole jammer device is shown in Figure 19. The dimensions for the

jammer are clearly seen in Figure 20. It is such a cute, small and portable device!

Fig. 4.9 The Jammer Device.


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4.6 Circuitry

The main electronic components of a jammer are:

Voltage-controlled oscillatorGenerates the radio signal that will interfere with the cellphone signal

Tuning circuit Controls the frequency at which the jammer broadcasts its signal bysending a particular voltage to the oscillator

Noise generatorProduces random electronic output in a specified frequency range tojam the cell-phone network signal (part of the tuning circuit)

RF amplification (gain stage) Boosts the power of the radio frequency output to highenough levels to jam a signal

4.7 Power supply

Smaller jamming devices are battery operated. Some look like cellphones and use cellphone

batteries. Stronger devices can be plugged into a standard outlet or wired into a vehicle's electrical

system.

All the electronic components starting from diode to Intel ICs only work with a DC supply

ranging from +5V to +12V. We are utilizing for the same, the cheapest and commonly available

energy source of 230v-50Hz and stepping down, rectifying, filtering and regulating the voltage.

The jammer's effect can vary widely based on factors such as proximity to towers, indoor &

outdoor settings, presence of buildings and landscape, even temperature and humidity play a role.

There are concerns that crudely designed jammers may disrupt the functioning of medical devicessuch as pacemakers.[citation needed]However, like cellphones, most of the devices in common use

operate at low enough power output (


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CHAPTER-5

USED OF CELL-PHONE JAMMERSCell phone jamming devices were originally developed for law enforcement and the military to

interrupt communications by criminals and terrorists. The bombs that blew up commuter trains in

Spain in March 2004, as well as blasts in Bali in October 2002 and Jakarta in August 2003, all

relied on cell phones to trigger explosives.

It has been widely reported that a cell-phone jammer thwarted an assassination attempt on

Pakistani President Musharraf in December 2003. When President Bush visited London in

November 2004, it was reported that British police considered using jammers to protect the

president's motorcade through London.

During a hostage situation, police can control when and where a captor can make a phone call.

Police can block phone calls during a drug raid so suspects can't communicate outside the area.

Cell-phone jammers can be used in areas where radio transmissions are dangerous, such as areas

with a potentially explosive atmosphere, such as chemical storage facilities or grain elevators.

The TRJ-89 jammer from Antenna System & Supplies Inc. carries its own electrical generator and

can block cellular communications in a 5-mile (8-km) radius.

Corporations use jammers to stop corporate espionage by blocking voice transmissions and photo

transmissions from camera phones. On the more questionable end of the legitimacy spectrum,

there are rumors that hotel chains install jammers to block guests' cell-phone usage and force them

to use in-room phones at high rates.


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5.1 Legal Issues

In the United States, United Kingdom, Australia and many other countries, blocking cell-phoneservices (as well as any other electronic transmissions) is against the law. In the United States,

cell-phone jamming is covered under the Communications Act of 1934, which prohibits people

from "willfully or maliciously interfering with the radio communications of any station licensed or

authorized" to operate. In fact, the "manufacture, importation, sale or offer for sale, including

advertising, of devices designed to block or jam wireless transmissions is prohibited" as well.

Jamming is seen as property theft, because a private company has purchased the rights to the radio

spectrum, and jamming the spectrum is akin to stealing the property the company has purchased. It

also represents a safety hazard because jamming blocks all calls in the area, not just the annoying

ones. Jamming a signal could block the call of a babysitter frantically trying to contact a parent or

a someone trying to call for an ambulance.

The Federal Communications Commission is charged with enforcing jamming laws. However, the

agency has not yet prosecuted anyone for cell-phone jamming. Under the U.S. rules, fines for a

first offense can range as high as $11,000 for each violation or imprisonment for up to one year,

and the device used may also be seized and forfeited to the government.

In most countries, it is illegal for private citizens to jam cell-phone transmission, but some

countries are allowing businesses and government organizations to install jammers in areas where

cell-phone use is seen as a public nuisance.

In December 2004, France legalized cell-phone jammers in movie theaters, concert halls and other

places with performances. France is finalizing technology that will let calls to emergency services

go through. India has installed jammers in parliament and some prisons. It has been reported that

universities in Italy have adopted the technology to prevent cheating. Students were taking photos

of tests with their camera phones and sending them to classmates.


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5.2 Alternatives to Jamming

While the law clearly prohibits using a device to actively disrupt a cell-phone signal, there are norules against passive cell-phone blocking. That means using things like wallpaper or building

materials embedded with metal fragments to prevent cell-phone signals from reaching inside or

outside the room. Some buildings have designs that block radio signals by accident due to thick

concrete walls or a steel skeleton.

Companies are working on devices that control a cell phone but do not "jam the signal." One

device sends incoming calls to voicemail and blocks outgoing calls. The argument is that the

phone still works, so it is technically not being jammed. It is a legal gray area that has not been

ruled on by the FCC as of April 2005.

Cell-phone alerter are available that indicate the presence of a cell-phone signal. These have been

used in hospitals where cell-phone signals could interfere with sensitive medical equipment. When

a signal is detected, users are asked to turn off their phones.

For a less technical solution, Caudal Partners, a design firm in Chicago, has launched the SHHH,

the Society for Handheld Hushing. At its Web site, you can download a note to hand to people

conducting annoying cell-phone conversations, expressing your lack of interest in what they're

talking about.


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CCHHAAPPTTEERR--66

AADDVVAANNTTAAGGEESS && DDIISSAADDVVAANNTTAAGGEESS

11..33AADDVVAANNTTAAGGEESS It is very necessary using cell phone jammers in the most divine temples like Tirumala. We can provide security to V.I.Ps from the anti-social elements. By using cell phone jammers we can maintain law and order for maintaining peace. By cell phone jammers we cant disturb other people in the public places like restaurants,

shopping places.

It is very necessary to use cell phone jammers in naxal feared places. This helps theauthorities to work their duty softly.

By using cell phone jammers in the vehicles, we can overcome accidents problem whichis very helpful to the people.

11..44DDIISSAADDVVAANNTTAAGGEESS Cost oriented. Requires special hardware. People feel inconvenience. V.I.P.s may loose some impartant calls.


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CHAPTER-7

APPLICATION

7.1 Cell Phone Jammer Applications

Cell phone jamming devices were originally developed for law enforcement and the military to

interrupt communications by criminals and terrorists. The bombs that blew up commuter trains in

Spain in March 2004, as well as blasts in Bali in October 2002 and Jakarta in August 2003, all

relied on cell phones to trigger explosives. It has been widely reported that a cell-phone jammer

thwarted an assassination attempt on Pakistani President Musharraf in December 2003. When

President Bush visited London in November 2004, it was reported that British police considered

using phone jammers to protect the presidents motorcade through London.

During a hostage situation, police can control when and where a captor can make a phone call.

Police can block phone calls during a drug raid so suspects cant communicate outside the area.

Cell-phone jammers can be used in areas where radio transmissions are dangerous, (areas with a

potentially explosive atmosphere), such as chemical storage facilities or grain elevators. The TRJ-

89 jammer from Antenna System & Supplies Inc. carries its own electrical generator and can block

cellular communications in a 5-mile (8-km) radius.

Corporations use jammers to stop corporate espionage by blocking voice transmissions and photo

transmissions from camera phones. On the more questionable end of the legitimacy spectrum,

there are rumors that hotel chains installjammers to block guests cell-phone usage and force them

to use in-room phones at high rates.

1. To maintain the complete silence in library & lecture hall.2. To avoid fraud in examination hall.3. To avoid disturbance in class room.4. For providing security in business conference, board of directors rooms, seminar, etc.5. For providing calm and peaceful atmosphere in hospital.
http://www.espow.com/wholesale-security-jammer.htmlhttp://www.espow.com/wholesale-security-jammer.html


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6. Church/Mosques/Cathedral/Temple/Religious establishment.CHAPTER-8

RESULT & FUTURE DEVELOPMENTS

8.1 Result

As we tested our jamming device, the result was a full success. The device was able to jam the

three cell phone carriers: Zain, Orange, and Umniah. The effective jamming range was around 30

meters. This is more than what it was designed for.

The reason is that in our calculations, we considered the worst case of having the cell phone close

to the base station.

It is expected that as the distance between the cell phone and the base station increases, the

effective jamming distance will increase. This is due to the fact that the amount of power reaching

the cell phone from the base station decreases as the cell phone moves farther from the base

station. The Figure in the next page shows the results. It can be clearly seen that the signal is "ON"

when the jammer is "OFF", while the signal disappears when the jammer isON.

The module was implemented as per the design considerations. The testing of the module wasdone sequentially beginning with cross-checking of the source code. The PCB was launched only

after careful examination of the source code and the PCB design.

When PCB was obtained the connectivity test was performed on the PCB. Once the PCB was

cleared for further work, all the components were tested individually for their proper working and

were placed onto the PCB.

The source code (Microcontroller) was compiled and debugged using Keil software and the

program was burned or fused onto the microcontroller using Atmel Programmer, the other code for

programming the card was compiled and debugged using Turbo C on the PC.


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8.2 Future Developments

The following modifications can be made to the present circuit, which leads to still smarter project.

One can add many regional frequency bands to the present system without much change in the

hardware. The Microcontroller chips software can be upgraded to handle the entire added

frequency channel with the help of suitable RF Transmitter.

This project is open for developments from all sides. It is the users imagination which limits the

working of this project. One can go on adding the extra, rich features to this project.

While the law clearly prohibits using a device to actively disrupt a cell-phone signal, thereare no rules against passive cell-phone blocking.

Companies are working on devices that control a cell phone but do not jam the signal.MAIN FEATURES OF THE PROJECT

1. 800 MHz and 900 MHz operated handsets can be paralyzed2. Uses very low output power to transmit signal and does NO harm to human health3.

The coverage area is a sphere area with its effective distance measured in the radius

4. Compact size and light weight5. Can be installed and operated easily.


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CONCLUSION

Cell phone jammer effectively jams the operation of cell phone such that providing high security to

mankind. It is flexible for future expansion also.

Cell phone jammer can be effectively used in all area for maintaining security of data. Cell phone

Jammer is an instrument used to prevent cellular phones from receiving signals from or

transmitting signals to base stations. The jamming generator must have all technical parameter

equal to a cell phone and the output power should be more than the signal available in that area.

The task of jamming a cell signal or preventing cell phone from receiving or transmitting signals is

somewhat difficulty. To achieve this task, the jammer must high grade of hopping generator, with

good bandwidth. When used, the Jammer effectively disables cellular phones.

These devices can be used in practically any location, but are found primarily in places where a

phone call would be particularly disruptive because silence is expected.

Cell phone jammers are very useful to the society from the anti-social elements. We can save our

national leaders. we can restrict the communication network between the anti-social elements by

using the cell phone jammers. Cell phone jammers prevent the students from carrying cell phones

to the colleges. As varying goes fine, it is very necessary to implement in all the colleges.

In this project, which turned out to be a full success, we designed a device that stops phone

ringing. This device could be used in places where ringing is not desired at specific times, as these

riggings may disturb people in such places. The designed device works in dual band. It jams both

the GSM 900 and GSM 1800 bands. The device was able to jam the three main cell phone carriers

in Jordan.


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The project was implemented according to the following plan:

We started by studying the jamming techniques, and GSM system to find the best jammingmethod. The system block diagram was also specified in this stage.

We searched for components that are needed for building this device, and specified themain components which were :

o For RF section, we needed two VCOs that operate at the needed bands, two poweramplifier, and two antennas.

o For the IF section, we used 555timer, Zener diode, mixer, PC power supply andsome discrete components (resistors and capacitors).

The schematic was drawn and some simulations for the IF-Section were performed. Then,we started to design the layout using Express PCB and AutoCAD softwares. The PCB was

built using the etching process on copper clad board.

All the IF-components were bought from local companies. Then, the IF-section was builtand tested.

After that, we began to search for the RF-components (VCO and the board) in the localmarket. Since we failed to collect these ICs from the local market, we had to order them

from "Digi-key" US company.

Finally, we assembled and tested the jammer. Fortunately, we got positive results. Bothbands were fully jammed.

We hope that this project will be useful for the community where such jamming devices are

needed.


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REFERENCES

www.google.com www.wikipedia.org www.celljammer.org www.electronics4you www.HowStuffWorks.com www.webopedia.com
http://www.google.com/http://www.wikipedia.org/http://www.celljammer.org/http://www.electronics4you/http://www.howstuffworks.com/http://www.webopedia.com/http://www.webopedia.com/http://www.howstuffworks.com/http://www.electronics4you/http://www.celljammer.org/http://www.wikipedia.org/http://www.google.com/


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APPENDIX

Part &Prices

Part amount Total Price

Power supply Power Supply 24bin 1 10 JD

IF section Resistor 10 0.5 JD

Capacitor 10 1.5 JD

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


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The layout of the jammer

Dimensions are in mm.

Drawing not to scale.

Cell Jammer Report

Documents

Transcript of Cell Jammer Report