Mobile signal jammer / Amzar Adib Muthal’lib, Mohammad Arief Muhd Bakri and Mohd Emil Iskandar Mohd Zulkifli

This report presents the design, implementation, and testing of a dual-band mobile phone jammer. This jammer works at GSM 900 and GSM 1800 simultaneously and will jam the signal at the mobile phone from transmitting or receiving signals.
A mobile signal jammer transmits on the same radio frequencies as the mobile phone, jamming the communication between the phone and the mobile phone base station in the tower. The jammer overpowers the mobile phone by transmitting a signal on the same frequency and at a high enough power that the two signals collide and cancel each other out.
The technology behind mobile signal jammer is very simple. The jamming device broadcasts an RF signal in the frequency range reserved for mobile phones that interferes with the mobile phone signal, which results in a "no network available" display on the mobile phone screen. All phones within the effective radius of the jammer are silenced.