Mobile Jammer report

Mobile Jammer

BY

Ranavasiya Mehul

10BIT047

Department Of Computer Science and Engineering

Institute Of Technology

Nirma University

Ahmedabad-382481

April 2013

Mobile Jammer

Seminar

Submitted in partial fulfillment of the requirements

For the degree of

Bachelor of Technology in Information Technology

By

Ranavasiya Mehul

10BIT047

Department Of Computer Science and Engineering

Institute Of Technology

Nirma University

Ahmedabad-382481

April 2013

iii

Certificate

This is to certify that the Seminar entitled ”Mobile Jammer” submitted by Ranavasiya

Mehul(10BIT047), towards the partial fulfillment of the requirements for the degree of

Bachelor of Technology in Information Technology of Nirma University, Ahmedabad

is the record of work carried out by him under my supervision and guidance. In

my opinion, the submitted work has reached a level required for being accepted for

examination. The results embodied in this Seminar, to the best of my knowledge,

haven’t been submitted to any other university or institution for award of any degree

or diploma.

Prof. Jitali Patel Prof. Pimal Khanpara

Assistant Professor, Assistant Professor,

CSE Department , CSE Department,

Institute of Technology, Institute of Technology,

Nirma University, Ahmedabad Nirma University, Ahmedabad

Dr. Sanjay Garg

Head Of Department,

CSE Department,

Institute of Technology,

Nirma University, Ahmedabad

iv

Abstract

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. A mobile Jammer is an instrument which is

used to prevent mobile phones from receiving signals from the base stations.Which

can be used in practically at any location, but are mostly found in places where a

phone call would be particularly disruptive because silence is expected.The concept of

jamming technology is studied in a step-by-step approach. Those steps include Intro-

duction to mobile jammer, Componets of mobile jammer, Mobile jamming techniques,

Design parameters for mobile jammer, Block diagram of mobile jammer and Legal

issues related with mobile jammer along with the Alternatives of mobile jammer.

v

Acknowledgements

I would like to express my special thanks of gratitude to my guide Prof. Pimal

Khanpara who gave me the golden opportunity to give her profound guidance in

this wonderful project on the Mobile jammer , which also helped me in doing a lot

of Research and i came to know about so many new things.I am really thankful to

them.

- Ranavasiya Mehul

10BIT047

Contents

Certificate iii

Abstract iv

Acknowledgements v

1 Introduction 2

1.1 Why mobile jammer is needed? . . . . . . . . . . . . . . . . . . . . . 2

1.2 Cell Phone Jamming Basics . . . . . . . . . . . . . . . . . . . . . . . 2

2 Components of Mobile Jammer 4

2.1 Voltage Controlled Oscillator(VCO) . . . . . . . . . . . . . . . . . . . 4

2.2 Tuning Circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

2.3 Noise generator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

2.4 RF Amplification Unit . . . . . . . . . . . . . . . . . . . . . . . . . . 5

2.5 Transmitting Antenna . . . . . . . . . . . . . . . . . . . . . . . . . . 6

2.6 Power Source . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

3 Mobile Jamming Techniques 8

3.1 Type ”A” Device . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

3.2 Type ”B” Device . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

3.3 Type ”C” Device . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

3.4 Type ”D” Device . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

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CONTENTS 1

3.5 Type ”E” Device . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

4 Design Parameters/ Specification of mobile jammer 10

5 Block Diagram of Mobile Jammer 13

5.1 Power Supply . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

5.2 IF Section . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

5.3 RF Section . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

6 Applications 16

7 Legal Issues and Alternatives of Cell Phone Jamming 18

7.1 Cell Phone Jamming Legal Issues . . . . . . . . . . . . . . . . . . . . 18

7.2 Alternatives to Cell Phone Jamming . . . . . . . . . . . . . . . . . . 19

8 Conclusion 20

8.1 Conclusion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

8.2 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

Chapter 1

Introduction

1.1 Why mobile jammer is needed?

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 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. Cell phones are basically handheld two-way radios. And like

any radio, the signal can be disrupted, or jammed.

A mobile Jammer is an instrument which is used to prevent mobile phones from

receiving signals from the base stations.Which can be used in practically at any

location, but are mostly found in places where a phone call would be particularly

disruptive because silence is expected.

1.2 Cell Phone Jamming Basics

Disrupting a cell phone is the same as jamming any other type of radio commu-

2

CHAPTER 1. INTRODUCTION 3

nication. A cell phoneworks 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.

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

rupting the 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

spectrumto the cell-phone users within range of the jamming device.

Chapter 2

Components of Mobile Jammer

Components of a mobile jammer include:

• Voltage Controlled Oscillator(VCO)

• Tuning Circuit

• Noise Source

• RF Amplification Unit

• Transmitting Antenna

2.1 Voltage Controlled Oscillator(VCO)

VCO is the most important among other parts. It is like a heart of our jammer. VCO’s

can be built using op-amps, resistors and capacitors, but the low cost, availability

and reliability of prefabricated VCO’s make it optimum to just purchase it. VCO

produces RF signal which will interact with the blocked device. Firstly we must select

frequencies which will be used in our signal blocking device. It is also important to

think about its size because we might wish to create a desktop mobile phone jammer

or a portable handheld jamming device.

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CHAPTER 2. COMPONENTS OF MOBILE JAMMER 5

Figure 2.1: Voltage Controlled Oscillator

2.2 Tuning Circuit

Tuning Circuit can be of two types:

• open-loop

• feedback

Open-loop is quite simple and requires just a few op-amps with additional passive

components.It is a sawtooth-wave generator which makes VCO to go from lowest

to highest frequency. The feedback is using PLL to adjust the VCOs frequency

constantly. For this purpose we need to use microcontroller. It is programmed once

and then connected to the VCO, thus it is not adjustable.

2.3 Noise generator

Produces random electronic output in a specified frequency range to jam the cell-

phone network signal (part of the tuning circuit).

2.4 RF Amplification Unit

RF Amplification Unit is what we need when we wish to increase the area covered

by our jammer along with its signal blocking power. The more power has our signal

blocker, the bigger radius it jams. The cost is, as we may guess, battery working

time. More power equals less time for battery to live.


Figure 2.2: Transmitting Antenna

2.5 Transmitting Antenna

Transmitting Antenna is a tool which transmits signals produced by your jammer.

The main characteristic of antenna is VSWR (Voltage Standing Wave Ratio). If your

antenna has VSWR of 3 or lower, then this is what you need, because the return loss

of this antenna is minimal.

VSWR: For example, the VSWR value 2:1 denotes a maximum standing wave

amplitude that is 2 times greater than the minimum standing wave value.

Generally we use SMA antennas due to their ability of being removed or replaced

easily. It is worth to mention that omnidirectional antennas are preferable, unless..

we like to use our cell phone jammer in a TV remote style!!

SMA (SubMiniature version A) connectors are coaxial RF connectors developed in

the 1960s as a minimal connector interface for coaxial cable with a screw type cou-

pling mechanism.

2.6 Power Source

Power Source makes our creation to become alive. Generally mobile phone jammers

use 5VDC to operate. Thus you may use Lithium-ion battery to supply our creation.

In the case of using common power source we will need power adapter. The power


adapter may be of one of two types: switched-capacitor voltage doubler or inductor-

based boost regulator. The first one is simple and efficient yet not regulated solution,

so we will need LDO regulator to fix the voltage. The second one is regulated but it

has bigger cost, more complex and requires precise specification of all components to

work properly

Chapter 3

Mobile Jamming Techniques

There are various types of jamming devices available which are using different jam-

ming techniques.

• Type ”A” Device

• Type ”B” Device

• Type ”C” Device

• Type ”D” Device

• Type ”E” Device

3.1 Type ”A” Device

Type ”A” Devices are simple Jammer.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 systems control channels for

call establishment.

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CHAPTER 3. MOBILE JAMMING TECHNIQUES 9

3.2 Type ”B” Device

Type ”B” Devices are also known as 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 quite area, functions as a detector.

It has a unique identification number for communicating with the cellular base station

3.3 Type ”C” Device

Type ”C” Devices are also known as 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 com-

patible terminal is instructed to disable its ringer or disable its operation, while within

the coverage area of beacon.

3.4 Type ”D” Device

Type ”D” Devices are Direct Receive Transmit Jammers. This jammer behaves like

a small, independent and portable base station, which can directly interact intelli-

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

is predominantly in receive mode and will intelligently choose to interact and block

the cell Phone directly if it is within close proximity of the jammer.

3.5 Type ”E” Device

Type ”E” Devices are used for EMI Shield - Passive Jamming. This technique is

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

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

attenuates, virtually all electromagnetic radiation from entering or leaving the cage -

or in this case a target room.

Chapter 4

Design Parameters/ Specification

of mobile jammer


ming techniques.

• The frequency bands

• Distance to be jammed (D)

• Jamming-to-signal ratio J/S

• Power calculations

• Free space loss

The Jamming Coverage Area for a particular model jammer should be consid-

ered a General or typical area of coverage. The situation may vary and is specific

to the site. Every JAMMING DEVICE outputs a JAMMING SIGNAL on one or

more frequencies at a particular OUTPUT POWER. The OUTPUT POWER of the

JAMMER will typically be stated in WATTS or in some Cases DBM, (decibels per

meter), or both. The OUTPUT POWER correlates generally to the COVERAGE

AREA that the JAMMER will provide an Effective blocking or JAMMING signal.

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CHAPTER 4. DESIGN PARAMETERS/ SPECIFICATIONOFMOBILE JAMMER11

However, because many factors affect both cellular phone Reception and jamming

efficiency the advertised or sated AREA of COVERAGE may be more or less than

What a manufacture states.

In most cases a JAMMER will be easier to implement and more effective indoors.

In urban settings and In high-rise buildings, a jammer will typically be more effective

on lower floors. This is because the Building and surrounding structures diminish

the cellular signal. In some cases a JAMMER will be more Effective when placed

on the side of a room or building which is closest to a cellular tower. And in other

Cases a JAMMER may be more effective when placed by a window or door. The

design of a jammer design begins with a desired area of coverage as it correlates to

a particular Frequency. Jammers like all radio devices operate according to certain

laws of physics and energy. The Jamming objective is to inject an interference signal

into the communications frequency so that the Actual signal is completely submerged

by the interference. It is important to notice that transmission can never be totally

jammed - jamming hinders the reception at the other end. The problem here for

the jammer is that only transmitters can be found using direction finding and the

Location of the target must be a specific location, usually where the jammer is located

and this is Because the jamming power is never infinite.

Jamming is successful when the jamming signal denies the usability of the commu-

nications transmission. In digital communications, the usability is denied when the

error rate of the transmission Cannot be compensated by error correction. Usually a

successful jamming attack requires that the jammer power is roughly equal to signal

power at the receiver. The effects of jamming depend on the, Jamming-to-signal ratio

(J/S) , Modulation scheme, Channel coding and Interleaving of the target system.

Generally Jamming-to-Signal ratio can be measured according to the following Equa-

tion.

Where:

Pj = jammer power

Pt = transmitter power

CHAPTER 4. DESIGN PARAMETERS/ SPECIFICATIONOFMOBILE JAMMER12

Figure 4.1: J/S Ratio

Gjr = antenna gain from jammer to receiver

Grj = antenna gain from receiver to Jammer

Gtr = antenna gain from transmitter to receiver

Grt = antenna gain from receiver to transmitter

Br = communications receiver bandwidth

Bj = jamming transmitter bandwidth

Rtr = range between communications transmitter and receiver

Rjt = range between jammer and communications receiver

Lj = jammer signal loss (including polarization mismatch)

Lr = communication signal loss

The above Equation indicates that the jammer Effective Radiated Power, which is

the product of Antenna gain and output power, should be high if jamming efficiency is

required. On the other hand, in Order to prevent jamming, the antenna gain toward

the communication partner should be as high as Possible while the gain towards

the jammer should be as small as possible. As the equation shows, the Antenna

pattern, the relation between the azimuth and the gain, is a very important aspect in

jamming. Also as we know from Microwave and shown in the equation distance has

a strong influence on the Signal loss. If the distance between jammer and receiver

is doubled, the jammer has to quadruple its Output in order for the jamming to

have the same effect. It must also be noted here that jammer path Loss is often

different from the communications path loss; hence giving the jammer an advantage

over Communication transmitters.

Chapter 5

Block Diagram of Mobile Jammer

There are main 4 sections in the block diagram of mobile jammer.

5.1 Power Supply

The mobile jammer was designed for fixed use, and to take its power from the regular

220V AC wall outlets. The IF RF sections of the jammer require +5, +9, and -9 DC

Voltages. So a dc-dual polarity power supply should be designed. The basic parts for

a power supply are rectifier, filter, and regulator. The rectifier coverts the ac input

voltage to a pulsating dc voltage and can be either half wave rectifier and full wave

rectifier, the one we use is the full wave rectifier which has the advantage that it allows

unidirectional current to the load during the entire cycle of the input voltage and the

Figure 5.1: Block diagram

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CHAPTER 5. BLOCK DIAGRAM OF MOBILE JAMMER 14

Figure 5.2: Power Suppy

Figure 5.3: IF Section

result of the full wave rectification is an output voltage with a frequency twice the

input frequency that pulsated every half-cycle of the input. The second part of the

power supply is the filter which eliminate the fluctuations in the output of the full

wave rectifier so as to produce a constant dc voltage, the filter is simply a capacitor

and its chosen to be as large as possible to minimize voltage ripple in the output. The

final part of the power supply is the regulator and it is used to provide the desired

constant dc output that is basically independent of the input voltage. Single chip

regulators were used to give +5, +9, and -9 dc voltages

CHAPTER 5. BLOCK DIAGRAM OF MOBILE JAMMER 15

Figure 5.4: RF Section

5.2 IF Section

The function of the IF-section of the Mobile jammer is to generate the tuning signal

for the VCO in The RF-Section, which will sweep the VCO through the desired range

of frequencies. This tuning signal is generated by a triangular wave generator along

with noise generator, and then offset by proper amount so as to sweep the VCO

output from the minimum desired frequency to a maximum. The triangle wave and

noise signals are mixed using Op-Amp configured as summer. Then a DC voltage is

added to the resulted signal to obtain the required tuning voltage.

5.3 RF Section

The RF-section is the most important part of the mobile jammer it consist of the

Voltage Controlled Oscillator (VCO), RF Power amplifiers, and the antenna. These

components were selected according to the desired specification of the jammer such

as the frequency range and the coverage range.

Chapter 6

Applications


ming techniques.

• To maintain the complete silence in library and lecture hall.

• To avoid fraud in examination hall.

• To avoid disturbance in class room.

• For providing security in business conference, board of directors rooms, semi-

nars, etc.

• For providing calm and peaceful atmosphere in Hospitals.

• Church/Mosques/Cathedral/Temple/Religious establishment

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 Lon-

don in November 2004, it was reported that British police considered using jammers

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CHAPTER 6. APPLICATIONS 17

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, (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 transmis-

sions 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.

Chapter 7

Legal Issues and Alternatives of

Cell Phone Jamming

7.1 Cell Phone Jamming Legal Issues

In the United States, United Kingdom, Australia and many other countries, blocking

cell-phone services (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

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CHAPTER 7. LEGAL ISSUES ANDALTERNATIVES OF CELL PHONE JAMMING19

jamming.

7.2 Alternatives to Cell Phone Jamming

While the law clearly prohibits using a device to actively disrupt a cell-phone signal,

there are no rules 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 Apr-+il 2005. Cell-phone

alerters 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, Coudal 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.

Chapter 8

Conclusion

8.1 Conclusion

At last we can say every device is acts as good aspects as well as bad aspects. In

many place cell phone jammer is useful but at many place it is a problem .for this we

can take a example that if at any place cell phone jammer is on than anybody wants

to use than there creates some problems. But its overall performance is very good

and helpful in our life.

8.2 References

• www.HowStuffWork.com

• wikipedia.org/wiki/Mobilephonejammer

• Mobile Personal Communications Committee of the Radio Advisory Board of

Canada, Use of jammer and disabler Devices for blocking PCS, Cellular Related

Services

• http://whatisacellphonejammer.com

• http://blog.jammer-store.com/2009/11/how-mobile-jammers-work

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