This paper presents the mobile Jammer for GSM with a fixed range. The jammer broadcast a radio frequency similar to that of the mobile and interferes with the signal of the mobile phone that results “No network available” display on the mobile screen. We have experimented with a lot of frequencies and found after tuning and comparison the best frequency for jamming the mobile phone.

Keywords : Mobile Signal Jammer,NE555 Timer, Cell Phone, Resister, Capacitor.