The document discusses cell phone jammers, which are devices that create 'dead zones' by preventing cell phones from receiving and transmitting signals. It covers their purpose, legal implications, and the technology behind how they work, including types, size, and effectiveness. Additionally, it addresses the advantages and disadvantages of jammers, highlighting their potential for misuse and the restrictions on their use in many countries.

1. Cell Phone JammerCell Phone Jammer
presented by:-presented by:-
Saumya Ranjan BehuraSaumya Ranjan Behura

2. CONTENTSCONTENTS
1> what is a Jammer ?1> what is a Jammer ?
2> Size of Jammer .2> Size of Jammer .
3> Why are Jammers used ?3> Why are Jammers used ?
4> How Jammers work ?4> How Jammers work ?
5> Inside a Jammer .5> Inside a Jammer .
6> Range of Jammer .6> Range of Jammer .
7> Good or Bad ?7> Good or Bad ?
8>Legal Issues .8>Legal Issues .
9>Conclusion .9>Conclusion .

3. WHAT IS A "JAMMER"?WHAT IS A "JAMMER"?
 Cell phone jammers are devices that create a temporaryCell phone jammers are devices that create a temporary
"dead zone" to all cell phone traffic in their immediate"dead zone" to all cell phone traffic in their immediate
proximity.proximity.
 A cell phone jammer is an instrument used to preventA cell phone jammer is an instrument used to prevent
cellular phones from receiving and transmitting thecellular phones from receiving and transmitting the
mobile signals to a base station. When used, the jammermobile signals to a base station. When used, the jammer
effectively disables cellular phones in the areaeffectively disables cellular phones in the area..
 Other types of jammers include radar jammerOther types of jammers include radar jammer
and radio jammerand radio jammer

4.  Some cell-phone jammers are made to look like actualSome cell-phone jammers are made to look like actual
phones. Others are briefcase-sized or larger. Thephones. Others are briefcase-sized or larger. The
biggest jammers used by police and the military can bebiggest jammers used by police and the military can be
mounted in vehicles for convoy security.mounted in vehicles for convoy security.
SIZE OF ASIZE OF A JAMMERJAMMER
Digital, portable cellphone
jammer designed for
military and police use

5. Cont..Cont..
A big jammer A portable jammer

6. WHY ARE JAMMERS USED?WHY ARE JAMMERS USED?
 A phone jammer provides the ultimate solution in anyA phone jammer provides the ultimate solution in any
area where cellular communications frequently causearea where cellular communications frequently cause
nuisance either by loud incoming call rings or resultingnuisance either by loud incoming call rings or resulting
loud telephone conversations.loud telephone conversations.
 Cell phone jamming devices were originally developedCell phone jamming devices were originally developed
for law enforcement and the military to interruptfor law enforcement and the military to interrupt
communications by criminals and terrorists. Examplescommunications by criminals and terrorists. Examples
include:securityzonespublictransport,include:securityzonespublictransport,,,classrooms,,
temples,tv & radio stations,jails,govt.buildings,militarytemples,tv & radio stations,jails,govt.buildings,military
bases,industries etcbases,industries etc. .

7.  During a hostage situation, police can control when andDuring a hostage situation, police can control when and
where a captor can make a phone call. Police can blockwhere a captor can make a phone call. Police can block
phone calls during a drug raid so suspects can'tphone calls during a drug raid so suspects can't
communicate outside the area.communicate outside the area.
 Corporations use jammers to stop corporate espionageCorporations use jammers to stop corporate espionage
by blocking voice transmissions and photoby blocking voice transmissions and photo
transmissions from camera phones.transmissions from camera phones.
Cont..Cont..

8. HOW JAMMERS WORKHOW JAMMERS WORK
 Jammers block cell phone use by sending out radioJammers block cell phone use by sending out radio
waves along the same frequencies that cellular phoneswaves along the same frequencies that cellular phones
use at a high enough power that the two signals collideuse at a high enough power that the two signals collide
and cancel each other out.and cancel each other out.
 This causes interference with theThis causes interference with the
communication of cell phonescommunication of cell phones
and the towers to render.the phonesand the towers to render.the phones
unusableunusable.. On most phones, theOn most phones, the
network would appear out of range.network would appear out of range.
 SoSo Jammers work by either disruptingJammers work by either disrupting
phone to tower frequencies or towerphone to tower frequencies or tower
to phone frequenciesto phone frequencies..

9. JAMMING BASICSJAMMING BASICS

10. Cont..Cont..
 To jam a cell phone, all you need is a device thatTo jam a cell phone, all you need is a device that
broadcasts on the correct frequencies. Althoughbroadcasts on the correct frequencies. Although
different cellular systems process signals differently, alldifferent cellular systems process signals differently, all
cell-phone networks use radio signals that can becell-phone networks use radio signals that can be
interrupted. GSM, used in digital cellular and PCS-interrupted. GSM, used in digital cellular and PCS-
based systems, operates in the 900-MHz and 1800-based systems, operates in the 900-MHz and 1800-
MHz bands in Europe and Asia and in the 1900-MHzMHz bands in Europe and Asia and in the 1900-MHz
(sometimes referred to as 1.9-GHz) band in the United(sometimes referred to as 1.9-GHz) band in the United
States. Jammers can broadcast on any frequency and areStates. Jammers can broadcast on any frequency and are
effective against AMPS, CDMA, TDMA,GSM andeffective against AMPS, CDMA, TDMA,GSM and
Nextel systems.Nextel systems.

11. INSIDE A JAMMERINSIDE A JAMMER
ANTENNAANTENNA ::
Every jamming device has an antenna toEvery jamming device has an antenna to
send the signal. Some are contained withinsend the signal. Some are contained within
an electrical cabinet. On stronger devices,an electrical cabinet. On stronger devices,
antennas are external to provide longerantennas are external to provide longer
range and may be tuned for individualrange and may be tuned for individual
frequencies.frequencies.

12. Cont..Cont..
 Power supplyPower supply
Smaller jamming devices are battery operated. SomeSmaller jamming devices are battery operated. Some
look like cell phone and use cell-phone batteries.look like cell phone and use cell-phone batteries.
Stronger devices are plugged into a standard outlet orStronger devices are plugged into a standard outlet or
wired into a vehicle's electrical systemwired into a vehicle's electrical system..
 CircuitryCircuitry
The main electronic components of a jammer are:The main electronic components of a jammer are:
 Voltage-controlled oscillatorVoltage-controlled oscillator - Generates the radio- Generates the radio
signal that will interfere with the cell phone signalsignal that will interfere with the cell phone signal
 Tuning circuitTuning circuit - Controls the frequency at which the- Controls the frequency at which the
jammer broadcasts its signal by sending a particularjammer broadcasts its signal by sending a particular
voltage to the oscillator.voltage to the oscillator.

13. RANGE OF A JAMMERRANGE OF A JAMMER
 The actual range of the jammer depends on its powerThe actual range of the jammer depends on its power
and the local environment, which may include hills orand the local environment, which may include hills or
walls of a building that block the jamming signal.Thewalls of a building that block the jamming signal.The
power depends on proximity to towers, indoor andpower depends on proximity to towers, indoor and
outdoor settings, even temperature and humidity play aoutdoor settings, even temperature and humidity play a
role. Most cell phone jammers come in 2 versions, onerole. Most cell phone jammers come in 2 versions, one
for Europe, North Africa and the Gulf states GSMfor Europe, North Africa and the Gulf states GSM
networks (900 & 1800) and one for the Americas &networks (900 & 1800) and one for the Americas &
Canada (800 & 1900 mhz) networksCanada (800 & 1900 mhz) networks
 Most jammers only have a range of about 50 to 80 feetMost jammers only have a range of about 50 to 80 feet
and will only effectively jam your immediateand will only effectively jam your immediate
surroundings. Low-powered jammers block calls in asurroundings. Low-powered jammers block calls in a
range of about 30 feet (9 m).range of about 30 feet (9 m).

14. Cont..Cont..
 Higher-powered units create a cell-free zone as large asHigher-powered units create a cell-free zone as large as
a football field. Units used by law enforcement can shuta football field. Units used by law enforcement can shut
down service up to 1 mile (1.6 km)down service up to 1 mile (1.6 km)
from the device.They are availablefrom the device.They are available
to cover large structures like officeto cover large structures like office
buildings, theaters and churches.buildings, theaters and churches.
They look like a miscellaneous boxThey look like a miscellaneous box
with wires sticking out & are usuallywith wires sticking out & are usually
mounted on walls or ceilings.mounted on walls or ceilings.

15. GOOD OR BADGOOD OR BAD
Along with its advantages jammers can be equally usedAlong with its advantages jammers can be equally used
for the bad.for the bad.
 They can in theory interfere with emergencyThey can in theory interfere with emergency
communications between police and rescue personnelcommunications between police and rescue personnel
 It also represents aIt also represents a safety hazardsafety hazard because jammingbecause jamming
blocks all calls in the area, not just the annoying ones.blocks all calls in the area, not just the annoying ones.
 Jammers can be used by criminals who break intoJammers can be used by criminals who break into
houses.houses.
 There are concerns that crudely designed jammers mayThere are concerns that crudely designed jammers may
disrupt the functioning of medical devices such asdisrupt the functioning of medical devices such as
pacemakers .pacemakers .

16. LEGAL ISSUESLEGAL ISSUES
 With the exception of Asian countries blocking cell-With the exception of Asian countries blocking cell-
phone services by the general public is against the lawphone services by the general public is against the law
in most countries like The United States, Unitedin most countries like The United States, United
Kingdom, Australia.Kingdom, Australia.
 The FCC (Federal Communications Commission) inThe FCC (Federal Communications Commission) in
the United States fines for a first offense ranging verythe United States fines for a first offense ranging very
high for each violation or imprisonment and the devicehigh for each violation or imprisonment and the device
used may also be seized and forfeited to theused may also be seized and forfeited to the
government.government.
 Governments are trying to make the best possible useGovernments are trying to make the best possible use
of jammers and planning to relax their restrictions onof jammers and planning to relax their restrictions on
using them in standard places like churches, movieusing them in standard places like churches, movie
theaters and courthouses.theaters and courthouses.

17. CONCLUSIONCONCLUSION
 Every technology has good aspect as well as bad aspectEvery technology has good aspect as well as bad aspect
the important thing is ,how we are using it.the important thing is ,how we are using it.
 Maybe someday governments will relax theirMaybe someday governments will relax their
restrictions on jammers and they will become standardrestrictions on jammers and they will become standard
in places like churches, movie theaters and courthouses.in places like churches, movie theaters and courthouses.
Until then, only government personnel. and outlawUntil then, only government personnel. and outlaw
jammers will be able to enjoy some peace and quiet atjammers will be able to enjoy some peace and quiet at
the movie theater or the ride via public transportationthe movie theater or the ride via public transportation
to workto work

18. REFERENCESREFERENCES
 [1][1] Cell phones jammers answer prayers of some. 2004Cell phones jammers answer prayers of some. 2004
Associated Press.p. Appeared on Nov. 2, 2004, editions of theAssociated Press.p. Appeared on Nov. 2, 2004, editions of the
Milwaukee Journal Sentinel.Milwaukee Journal Sentinel.
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Zhu; Degang Sun, Digital Society, 2007. ICDS apos;07. FirstZhu; Degang Sun, Digital Society, 2007. ICDS apos;07. First
International Conference on the Volume , Issue , Jan. 2007International Conference on the Volume , Issue , Jan. 2007
Page(s):31 - 31Page(s):31 - 31
 [3][3] Eyrolle, H. and J. Cellier, The effects of interruptions inEyrolle, H. and J. Cellier, The effects of interruptions in
work activity: Field and laboratory results. Applied Ergonomics,work activity: Field and laboratory results. Applied Ergonomics,
2000. 31: p. 537-543.2000. 31: p. 537-543.
 [4][4] Knock on wood [cell-phone jamming device] Bansal,Knock on wood [cell-phone jamming device] Bansal,
R.Microwave Magazine, IEEEVolume 5, Issue 1, Mar 2004R.Microwave Magazine, IEEEVolume 5, Issue 1, Mar 2004
Page(s): 38 - 40.Page(s): 38 - 40.

19. QUERIES ? ? ?QUERIES ? ? ?
Thank YouThank You