How a Cell Phone Blocker Works

How a Cell Phone Blocker Works

cell phone blocker

There are cell phone blocker pouches on the market that work on the principals of a Faraday cage – essentially preventing the signal from reaching the phone via a form of antenna that creates electromagnetic interference. But then there are cell phone jammer devices which send out ‘white noise’ that collides with signals on the frequency and prevents the propagation of the signal between the handset and cell tower.

Phone Blocker Devices Emit White Noise to Break Connections

These cell phone blockers are, in may countries, of questionable legal status when used by those outside the military and law enforcement communities. Care should be used prior to building, purchasing, or utilizing such devices and you should always check your local regulations prior to any such activity.

Cell Phone Jammer Legal Issues

The use of GPS and cell phone jammer equipment has risen significantly in recent years, as more people become aware of the need for privacy, and take active steps to protect it.  While police, prison, and military cell phone jammer use make up the primary consumers, many private companies and citizens are also taking advantage of this equipment where allowed by law.  Legality of cell phone jammer use

The law governing cell phone jammer use differs in many countries, and is very clear in some countries while it is less than direct in others. Below is a list of those countries and their laws as found on the wikkipedia page:
Armenia : illegal
Australia: illegal to operate, supply or possess[3]
Belgium: illegal to sell, possess and operate (licensed part of the spectrum).
Brazil: illegal, but installation in jails have been proposed.[4]
Canada: illegal, except by federal law-enforcement agencies who have obtained approval[5]
People’s Republic of China: Used by the Education government department as a method of thwarting cheating in schools. During major end of year exams, mobile phone jammers are used in areas surrounding high schools to prevent students inside from receiving calls or text messages, which may be used for illicit purposes. In some municipalities however, rather than the use of jammers, mobile signal towers close to schools are temporarily shut down for the duration of the week as exams are in progress.
Czech Republic: illegal.
Denmark: illegal.
Egypt: illegal.
Finland: illegal.
France: France legalized cell-phone jammers in (movie) theaters and other places with performances in 2004. Abandoned due to complaints regarding emergency calls. Still legally used inside jails.
Germany: illegal, but installation in jails has been proposed.
India: legal, Government, Religious Places, Prisons and Educational Institutions use jammers.
Iran: illegal to operate for civilians but allowed for police forces and military. It is however legal to own such units, which can be bought in electronic markets without a licence. In most jails, libraries and university classrooms such jammers are already in use. In the 2009–2010 Iranian election protests, police forces used cellphone and Bluetooth jammers.
Ireland: illegal to operate. Legally used inside prisons by the Irish Prison Service.
Italy: technically not illegal to own, but largely illegal to operate, since the Italian law specifically prohibits the disturbing of radio and telephone communications. GSM jammers are however legal to be used in places like hospitals, churches, movie theatres and other places with performances, and other buildings where and when the use of mobile telephones may result in a leak of sensitive information: on such occasions, jammers are legal as long as their operation doesn’t interfere with electronic medical equipment (such as pace-makers) and allows mobile phones to make emergency calls. Tri-Band Jammers are reserved to, and in use with, the police forces and are being experimented in prisons.
Japan: Illegal to use, but legal to own. Buying of mobile short range versions is allowed. Use of fixed high output jammers with long range is illegal, with fines of up to max $250,000USD and/or 5 years in prison.
Mexico: legal inside jails, often used also in churches and hospitals.
New Zealand: Illegal to sell, manufacture or use.[6] Legal inside jails by Department of Corrections.[7]
Norway: illegal to own and operate. The police and the military can use jammers in situations in which it is necessary.
Pakistan: It’s illegal to operate a jammer without the N.O.C. from Ministry of Interior and Ministry of Telecom. Further State Bank of Pakistan banned the installation of same in Banks, PTA (Pakistan Telecommunication Authority’s Enforcement Division continuously monitors and receives complaints and takes actions to remove jammers which are installed without N.O.C.
Poland: legal to trade and own, while not operational; illegal to use in public (licensed part of the spectrum); illegal to cause interference to 3rd party communication (without notice and permission); legal to use on own property with small power (both above clauses apply).
Slovakia: illegal.
Sweden: illegal. Legal inside jails and for military use.[8]
Switzerland: illegal.
Turkey: illegal. Only the police and the military use jammers.
Ukraine: legal, planned to be used in schools[9]
United Kingdom: illegal to use, but legal to own. Installation in jails has been proposed[10]
United States: Cell phone blocking devices are used by federal officials under certain circumstances.[citation needed] Privacy rights of property owners may affect the policy and application of law within buildings[citation needed]. For radio communications, it is illegal to operate, manufacture, import, or offer for sale, including advertising (Communications Act of 1934).[11] Blocking radio communications in public can carry fines of up to $112,000 and/or imprisonment of up to one year.[12] The Homeland Security Act of 2002 may override the Communications Act of 1934.[13]

Jammer Use for Police and Military

Disruption of communications can be an important and useful tool for military and law enforcement applications.  By limiting the availability of cell phone signals, law enforcement representatives are able to effectively gain control the communication in an area  This can be particularly useful in several scenarios, such as:

Prison Cell Phone Jammers

1>    Prisons: The use of cell phones in prisons has been linked to witness harassment and targeting, smuggling of illegal items into prisons, and escape plans.  By effectively shutting down cell phone service within the prison walls with a prison jammer, officials gain control of the inmate population’s communications by forcing them to use monitored phone lines, effectively stopping any nefarious planning in its early stages.

Police Cell Phone Jammers

2>    Police Raids: Police and SWAT teams serving high risk warrants or searches often use a cell phone jammer in the area prior to the raid.  Deployment of a signal jammer disrupts the ability of the suspect to warn others, communicate, or otherwise make strategic plans which could impede the law enforcement officers’ objectives.

Military Cell Phone Jammers and Bomb Jammers

3>    Military: Uses of a military bomb jammer include scenarios related to those above, as well Use of jammers for militaryas deploying the jammers in forward vehicles for convoys or escorts.  By blocking cell phone signals in an area, cell phone remote detonated IED’s are effectively rendered useless.  Many special forces units are now employing smaller man-pack jammers for patrols, to keep them safer as well.

The civilian market has also taken to use of smaller, less powerful cell phone jammers, which are now used in schools to prevent cheating on examinations, as well as other areas such as funeral homes, theaters, and places of worship, where cell phone disruptions are improper and obtrusive.

Use and Deployment of Mobile Cell Phone Jammers