Cell Phone Jammers

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  • Topic: Mobile phone, Base station, GSM
  • Pages : 5 (1541 words )
  • Download(s) : 788
  • Published : May 20, 2011
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Cell Phone Jammers

Who does not have or use cell phones as of today’s 2010? “According to the Cellular Telecommunications and Internet Association, almost 195 million people in the United States had cell-phone service in October 2005.” The statistics shows that cell phones are everywhere these days. It’s great to have cell phones and be able to call anyone anytime in the day whether it’s for socializing or seeking for help if stuck anywhere. However, people have forgotten the purpose of having this wonderful handheld two-way radio and its usage. As a matter fact, cell phones users are becoming ignorant and careless day by day when they forget when to stop talking and if it is in public places, like restaurants, movie theaters, shopping malls etc than the surrounding public suffer the most.

What is a cell phone jammer and how do they work?

Cell phone jammers are devices that create a temporary "dead zone" to all cell phone traffic in their immediate proximity (range). They come in two versions, one for European and the Gulf States GSM networks (900 & 1800) and one for the U.S.A & Canada (800 & 1900 MHz) networks. The range of a personal cell phone jammer can be from 10 meters to 100 meters. Larger cell phone jammers are more powerful and have a range that can be measured in miles. A cell phone jammer has three antennas, one each for GSM, 3G and DCS. The jammer works by broadcasting a white noise signal or a wave bubble. Firstly, the jammer needs to be charged for at least an hour before it can be turned on. Secondly, once they are charged and turned on, cell phones in the proximity will have no service available and all calls will be lost. Some cell phones will switch to searching, which means their signal is knocked out. The signal will be normalize once the jammer is turned off. It is like the concept of on/off switches where if it is high you get output or nothing if it is low.

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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. So disrupting a cell phone is same as jamming any other type of radio communications which is transmitted through the air, often over millions of miles. Below is the picture which demonstrates that.

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Between this 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. Below is the picture which demonstrates the actual process of it.

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Technically, the way this works is that jamming devices cranks up by transmitting a signal on the same frequency at a high power so that the signals collide and cancel each other out. Cell phones uses two separate frequencies, one for talking and one for listening simultaneously. 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 tri-mode phones that automatically switch among different network types to find an open signal. Some cell-phone jammers are made to look like actual phones and others are briefcase-sized or larger. Simply, a cell phone can be jammed by using a device that broadcasts on the correct frequencies.

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Who uses cell phone jammers in the U.S?

Jammers are typically used by the police and military to control or disrupt communication during hostage situations and bomb threats. The US military routinely uses jammers to protect secure military areas from electronic surveillance. It is illegal to own and sell jammers to civilian customers in U.S. However, it is available to purchase from British, Israeli and Asian electronic websites. It is legal to sell in U.K but it is illegal for civilians to use them. The FCC in the United States has outlawed the sale and use of...
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