ACKNOWLEDGEMENT. I am also obliged to the faculty of ECE Department for having given me their timely suggestions in my venture.

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Barry McKenzie
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1 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. 1

2 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 2

3 interference, so the jammer must recognize and match the power increase from the phone. CONTENTS 1. INTRODUCTION INSIDE A CELL PHONE SOURCE OF RADIATION WHY TO USE JAMMER JAMMING BASICS HOW IT WORKS INSIDE A CELL-PHONE JAMMER BLOCK DIAGRAM WORKING SPECIMEN OF CELL-PHONE JAMMERS LIMITATIONS CONCLUSION REFERENCE 21 3

4 . 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 4

5 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) 5

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

6 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 6

7 a 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 7

8 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 landbased 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).

9 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 9

wave 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.

10 wave 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 10

11 electromagnetic 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 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

12 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. 12

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.

13 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

14 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 dualmode 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

15 INSIDE A CELL-PHONE JAMMER Photo courtesy Netline Communications Technologies (NCT) Ltd. Cell-phone jammer 15

16 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. 16

17 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

18 WORKING 18

19 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

20 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 21

The jammer has an output power of about 20mW and an effective range of up to

22 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 meters radius in optimum conditions, depending on the type and location of cellular system. 22

23 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

24 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 voic 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

25 REFERENCE

CELL PHONE JAMMERS. By Priyanjali (472) A.Divya (466) SPHOORTHY ENGINEERING COLLEGE

CELL PHONE JAMMERS. By Priyanjali (472) A.Divya (466) SPHOORTHY ENGINEERING COLLEGE CELL PHONE JAMMERS By Priyanjali (472) A.Divya (466) SPHOORTHY ENGINEERING COLLEGE CONTENTS What is Jammer? Size of Jammer Why Jammers are used? How Jammer works? What inside the Jammer? Applications of