Jammer

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What Does Jammer Mean?

In mobile computing, a jammer is a mobile communications device that transmits on the same frequency range as a cellphone to create strong cell tower interference and block cellphone signals and call transmission.

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Jammers are usually undetectable, and users may experience minimal effects such as poor signal reception. Jamming devices may be used in any location but are typically deployed where cellphone use may be disruptive, such as in libraries and restaurants.

Techopedia Explains Jammer

A working cellphone must be in constant communication with its network provider via a cell tower or base station. By sending out radio waves in cellphone frequencies, jammers launch denial-of-service attacks (DoS), causing mobile devices to lose base station communication.

Jammers come in a variety of shapes and sizes, including:

  • Portable and compact devices, like mobile phones
  • Box-shaped units that are similar to routers
  • Larger and far-reaching briefcase-style format

All jamming device types have three main parts, as follows:

  • An antenna to connect the device
  • A power supply or battery
  • Circuitry, which includes a voltage-controlled oscillator, tuning circuit, noise generator and radio frequency (RF) amplification

Handheld jammers are capable of disrupting signals within nine to 30 meters, while more powerful jammers create a huge bubble stretching as far as a mile or 1.6 kilometers.

In many countries, jammers are illegal, except in the military, law enforcement and other government agencies, where jammers are largely used to prevent bomb detonation or to isolate suspects in hostage situations.

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Margaret Rouse
Technology Expert
Margaret Rouse
Technology Expert

Margaret is an award-winning technical writer and teacher known for her ability to explain complex technical subjects to a non-technical business audience. Over the past twenty years, her IT definitions have been published by Que in an encyclopedia of technology terms and cited in articles by the New York Times, Time Magazine, USA Today, ZDNet, PC Magazine, and Discovery Magazine. She joined Techopedia in 2011. Margaret's idea of a fun day is helping IT and business professionals learn to speak each other’s highly specialized languages.