subject: How Cell Phone Jammers Work [print this page] How Cell Phone Jammers Work How Cell Phone Jammers Work
Disrupting a mobile phone is the same as jamming any other type of radio communication. A mobile phone works by communicating with its service network through a cell tower or base station. Cell towers divide a city in to small areas, or cells. As a cell-phone user drives down the street, the signal is handed from tower to tower.
A jamming gizmo transmits on the same radio frequencies as the mobile phone, disrupting the communication between the phone and the cell-phone base station in the tower.
It's a called a denial-of-service assault. The cell phone jammer denies service of the radio spectrum to the cell-phone users within range of the jamming device.
Jamming devices overpower the cell phone by transmitting a signal on the same frequency & at a high power that the signals collide & cancel each other out. Cell rings are designed to add power in the event that they experience low-level interference, so the jammer must recognize & match the power increase from the phone.
Cell rings are full-duplex devices, which means they use separate frequencies, for speaking & for listening simultaneously. Some jammers block of the frequencies used by cell rings, which has the effect of blocking both. The phone is tricked in to thinking there is no service because it can receive of the frequencies.
To jam a cell phone, all you require is a tool that broadcasts on the correct frequencies. Although different cellular systems method signals differently, all cell-phone networks use radio signals that can be interrupted. GSM, used in digital cellular & PCS-based systems, operates in the 900-MHz & 1800-MHz bands in Europe & Asia & in the 1900-MHz (sometimes often called one.9-GHz) band in the United States. Jammers can broadcast on any frequency & are effective against AMPS, CDMA, TDMA, GSM, PCS, DCS, iDEN & Nextel systems. Elderly style analog cell rings & today's digital devices are equally susceptible to jamming.
Less complex devices block group of frequencies, while sophisticated jammers can block several types of networks without delay to head off dual-mode or tri-mode rings that automatically switch among different network types to find an open signal. A quantity of the high-end devices block all frequencies without delay, & others can be tuned to specific frequencies.
The actual range of the jammer depends on its power & the local surroundings, which may include hills or walls of a building that block the jamming signal. Low-powered jammers block calls in a range of about 30 feet (9 m). Higher-powered units generate a cell-free zone as massive as a footy field. Units used by law enforcement can shutdown service up to one mile (one.6 km) from the tool.
