There is no possibility for students to cheat in College Entrance Examination by cell phones with the help of 3G mobile phone jammer. If you have the same opinion, then you are wrong. It turns out that mobile phone signal jammer cannot block the signal of 3G cell phone. During the two days of College Entrance Examination, lots of schools send more teachers to invigilate students to prevent them from cheating. 

 

         Why the mobile phone signal jammer cannot block 3G signal? In fact, a mobile phone jammer has limited channels, which means it can only block limited signals. If the school wants to block the signals of all channels, it has to fix more jammers near the exam rooms, which will increase the cost. School can use a mixed jammer to block the signals of all channels, but it will cause a huge problem that the cell phone communication hundreds of meters around school may fail. In that case, the only way to ensure no cheating is to increase the number of teachers to invigilate students.