cell phone jammers seminar report’ 06 … phone jammers seminar report’ 06 acknowledgement ......

Cell Phone Jammers Seminar Report’ 06

ACKNOWLEDGEMENT

I express my sincere gratitude to Mr.Shiju P.P,Head of Department for

rendering me all facilities and guiding me right through the end for the successful

completion and presentation of the seminar.

I also express my gratitude to my seminar guide Mr. Rajesh Kumar lecturer

ECE Department for the support and encouragement given for the successful

completion and presentation of the seminar.

I am also obliged to the faculty of ECE Department for having given me their

timely suggestions in my venture.

I would also want to express my sincere thanks to my friends for the help

extended by them.

Dept of ECE LBSCE, Kasaragod

1


ABSTRACT

Radiation in cell phones is generated in the transmitter and emitted through

the antenna. Cell phones have low-power transmitters in them.

The radio waves that send the encoded signal are made up of electromagnetic

radiation propagated by the antenna. 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.

Technology that blocks cellular signals could impose etiquette in public.

Little book-sized devices called cell jammers may be as ubiquitous as cells some day.

The jammers emit low-level radiofrequencies that thwart mobile phone signals within

a pre-set radius, making a cell out of network reach for the cell-user. The most

successful range of jammers are manufactured in Israel, the U.S. and the U.K. and

cost around Rs. 2 lakhs each or more.

Jammers work in one of two ways. Some devices set their signal to the same

frequency as pagers and mobile phones, cutting off communication between handsets

and base stations. Others work as electronic filters that fool mobile phones into

thinking there are no frequencies available to make or receive calls.

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


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interference, so the jammer must recognize and match the power increase from the

phone.

CONTENTS

1. INTRODUCTION 01

2. INSIDE A CELL PHONE 02

3. SOURCE OF RADIATION 06

4. WHY TO USE JAMMER 08

5. JAMMING BASICS 09

6. HOW IT WORKS 10

7. INSIDE A CELL-PHONE JAMMER 12

8. BLOCK DIAGRAM 14

9. WORKING 15

10. SPECIMEN OF CELL-PHONE JAMMERS 16

11. LIMITATIONS 19

12. CONCLUSION 20

13. REFERENCE 21


3


INTRODUCTION.

Cell phone jamming devices were originally developed for law enforcement

and the military to interrupt communications by criminals and terrorist .The bombs

that blew up commuter trains in Spain in march 2004,as well as blast in Bali in

October 2002,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 Musharraff in December 2003

During hostage situation police can control when and where a capture can

make a call. Police can block calls during drug raid so suspects can’t communicate

outside area .Corporations use jammers to stop corporate espionage by blocking

voice transmissions and photo transmissions from camera phones


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INSIDE A CELL PHONE

On a "complexity per cubic inch" scale, cell phones are some of the most

intricate devices people use on a daily basis. Modern digital cell phones can process

millions of calculations per second in order to compress and decompress the voice

stream.

If you take a cell phone apart, you find that it contains just a few individual parts:

• An amazing circuit board containing the brains of the phone

• An antenna

• A liquid crystal display (LCD)


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• A keyboard (not unlike the one you find in a TV remote control)

• A microphone

• A speaker

• A battery

The circuit board is the heart of the system. Here is one from a typical Nokia digital

phone:

The front and back of the circuit board

In the photos above, you see several computer chips. Let's talk about what

some of the individual chips do. The analog-to-digital and digital-to-analog

conversion chips translate the outgoing audio signal from analog to digital and the

incoming signal from digital back to analog. The digital signal processor (DSP) is


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Cell Phone Jammers Seminar Report’ 06a highly customized processor designed to perform signal-manipulation calculations

at high speed.

The microprocessor handles all of the housekeeping chores for the keyboard

and display, deals with command and control signaling with the base station and

also coordinates the rest of the functions on the board.

The microprocessor

The ROM and Flash memory chips provide storage for the phone's operating

system and customizable features, such as the phone directory. The radio frequency

(RF) and power section handles power management and recharging, and also deals

with the hundreds of FM channels. Finally, the RF amplifiers handle signals

traveling to and from the antenna

Transmission


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Cell phones have low-power transmitters in them. Many cell phones have

two signal strengths: 0.6 watts and 3 watts (for comparison, most CB radios transmit

at 4 watts). The base station is also transmitting at low power. Low-power

transmitters have two advantages:

• The transmissions of a base station and the phones within its cell do not

make it very far outside that cell. Therefore, in the figure above, both of the

purple cells can reuse the same 56 frequencies. The same frequencies can

be reused extensively across the city.

• The power consumption of the cell phone, which is normally

batteryoperated, is relatively low. Low power means small batteries, and this

is what has made handheld cellular phones possible. The cellular approach

requires a large number of base stations in a city of any size.

A typical large city can have hundreds of towers. But because so many people

are using cell phones, costs remain low per user. Each carrier in each city also

runs one central office called the Mobile Telephone Switching Office

(MTSO). This office handles all of the phone connections to the normal land-

based phone system, and controls all of the base stations in the region.


8


SOURCE OF RADIATION

Electromagnetic radiation is made up of waves of electric and magnetic

energy moving at the speed of light, according to the Federal Communications

Commission (FCC). All electromagnetic energy falls somewhere on the

electromagnetic spectrum, which ranges from extremely low frequency (ELF)

radiation to X-rays and gamma rays.

When talking on a cell phone, a transmitter takes the sound of your voice and

encodes it onto a continuous sine wave. A sine wave is just a type of continuously

varying wave that radiates out from the antenna and fluctuates evenly through space.

Sine waves are measured in terms of frequency, which is the number of times a


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Cell Phone Jammers Seminar Report’ 06wave oscillates up and down per second. Once the encoded sound has been placed

on the sine wave, the transmitter sends the signal to the antenna, which then sends

the signal out.

Radiation in cell phones is generated in the transmitter and emitted through the antenna.

Cell phones have low-power transmitters in them. A handheld cell phone

operates on about 0.75 to 1 watt of power. The position of a transmitter inside a

phone varies depending on the manufacturer, but it is usually in close proximity to

the phone's antenna. The radio waves that send the encoded signal are made up of


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Cell Phone Jammers Seminar Report’ 06electromagnetic radiation propagated by the antenna. The function of an antenna

in any radio transmitter is to launch the radio waves into space; in the case of cell

phones, these waves are picked up by a receiver in the cell-phone tower.

WHY TO USE JAMMER

Cell phones are everywhere these days. According to the Cellular

Telecommunications and Internet Association, almost 195 million people in the

United States had cell-phone service in October 2005. 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. It is also

observed that teenagers where cheeting on exams by sending text messages or

taking pictures of tests .in such circumstances cell phones have become

disturbance .So it is important to avoid cell phones Cell jammers are employed in

places where silence is preffered, like religious places, exam halls and libraries

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.


11


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.

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.


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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.

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, 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


13

Cell Phone Jammers Seminar Report’ 06both. 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 trimode 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

cellphone 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. Oldfashioned

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

Network before jamming Network after jamming


14


INSIDE A CELL-PHONE JAMMER

Photo courtesy Netline CommunicationsTechnologies (NCT) Ltd.

Cell-phone jammer


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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

ithin 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 cell phone signal

• Tuning circuit - Controls the frequency at which the jammer broadcasts its

signal by sending a particular voltage to the oscillator .

• Noise generator - Produces random electronic output in a specified

frequency range to jam the cell-phone network signal (part of the tuning

circuit).

• RF amplification (gain stage) - Boosts the power of the radio frequency

output to high enough levels to jam a signal .


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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.

BLOCK DIAGRAM


17


WORKING


18


Noise generator produces random electronic output in a specified

frequency range to jam the cell-phone network signal (part of the tuning

circuit).This output is given as input for the phase detector and VCO the output is

also given as another input. The phase detector compares the input frequency with

VCO frequency and generates a dc voltage . this dc voltage proportional to the

phase difference between the two input frequencies .This voltage is often reffered

to as error voltage. The output of phase detector is applied to the low pass filter,

which removes the high frequency noise and produce dc level. This dc level, in

turn, is the input to the voltage controlled oscillator (VCO).The VCO frequency is

compared with the input frequencies and adjusted until it is equal to the input

frequencies .VCO output is radio signal that will interfere with the cell phone

signal. This is given to RF power amplifier stage to- boost the power of the radio

frequency output to high enough levels to jam a signal .

SPECIMEN OF CELL-PHONE JAMMERS


19


• What is Cellular phone-call Blocker?

This is an instrument to stop using cellular phone by shielding the electric-wave

from base station.

• Specifications


20



21


SH066 GSM CELL PHONE JAMMER

A new GSM cell phone jammer, the SH066 that is designed to look like

another cell phone has been launched. The jammer has an output power of about

20mW and an effective range of up to 10 – 15 meters radius in optimum conditions,

depending on the type and location of cellular system.


22


LIMITATIONS

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 a signal could block the call of a babysitter frantically trying to contact a

parent or a someone trying to call for an ambulance.

However, in some “high risk” areas, such as hospitals where mobile phone

interferes with medical equipment, jamming technology, which creates radiation of its

own, intensifies the problem


23


CONCLUSION

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

signal, there are no rules against passive cell-phone blocking. 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.

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.

In most of the countries, it is illegal for private citizens to jam cell phone

transmission, but some countries are allowing business and government

organizations to install jammers in areas where cell phones use is seen as a public

nuisance. The leaders of India's parliament revealed they had already installed the

devices to avoid interruptions during sessions.

However, in some “high risk” areas, such as hospitals where mobile phone

interferes with medical equipment, jamming technology, which creates radiation of its

own, intensifies the problem


24


REFERENCE

• www.howstuffworks.com

• www.globalgadgetuk.com

• www.vlsibank.com

• www.bsnl.in

• www.cellular.co.za

• www.techtv.com

• www.zdnet.com.au

• www.google.com


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http://www.google.com/

http://www.zdnet.com.au/

http://www.techtv.com/

http://www.cellular.co.za/

http://www.bsnl.in/

http://www.vlsibank.com/

http://www.globalgadgetuk.com/

http://www.howstuffworks.com/

cell phone jammers seminar report’ 06 … phone jammers seminar report’ 06 acknowledgement ......

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