Cell Jammer.docx - 123SeminarsOnly

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
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Cell Phone Jammers
Seminar Report’ 06
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
Dept of ECE
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Cell Phone Jammers
Seminar Report’ 06
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
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Cell Phone Jammers
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.
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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Cell Phone Jammers
Seminar Report’ 06
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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Cell Phone Jammers
Seminar Report’ 06
• 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’ 06
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
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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.
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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
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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
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Cell Phone Jammers
Seminar Report’ 06
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 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.
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Cell Phone Jammers
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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.
to tower.
As a cell-phone user drives down the street, the signal is handed from 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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Cell Phone Jammers
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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
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Cell Phone Jammers
Seminar Report’ 06
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 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.
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Network before jamming Network after jamming
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Cell Phone Jammers
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INSIDE A CELL-PHONE JAMMER
Photo courtesy Netline Communications
Technologies (NCT) Ltd.
Cell-phone jammer
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Cell Phone Jammers
Seminar Report’ 06
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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Cell Phone Jammers
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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.
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BLOCK DIAGRAM
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Cell Phone Jammers
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WORKING
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Cell Phone Jammers
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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 .
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SPECIMEN OF CELL-PHONE JAMMERS
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Cell Phone Jammers
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• What is Cellular phone-call Blocker?
This is an instrument to stop using cellular phone by shielding the electric-wave
from base station.
• Specifications
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Cell Phone Jammers
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Cell Phone Jammers
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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.
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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
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Cell Phone Jammers
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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
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Cell Phone Jammers
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• 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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REFERENCE
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