The cell phone users has increased in great numbers these days. The count of the cell phone users in the United States alone is over 195 million from October 2005. In Europe, the number is even larger.
People use their cell phones everywhere, do not have the courtesy to look for the bad effect in some areas like Concerts, Movie Theatres, Churches etc. It is very distracting yet embarrassing because people sharing their personal details over the phone and everyone is listening.
Jamming a cell phone signal is similar to disrupting any type of radio communication. A cell phone works on the basis of its service station signals a jamming device transmits similar radio frequencies of the cell phone and generates a denial of service attack. The radio spectrum within its range gets disrupted in this way.
A cell phone jammer operates in the same frequency field as the mobile operators. Like in the GSM mobile network, the frequency is 900MHz and 1800 MHz in Europe and Asia and the 1.9GHz for US. Jammers are also effective against CDMA, AMPS, iDEN, DCS and other communication bands and technologies. The analog and digital cell phone are equally vulnerable to jamming. The range of a jamming device depends on its power source and location. A jammer of different form and sizes starting with the portable one is capable of jamming signals of about 30 Ft range. It can go up to 1 mile for the bigger devices.