Every year in the CET-4 and CET-6 tests in colleges and universities, there will be listening test content. Before the test starts, the test room will turn on the cell phone jammer to interfere with the mobile phone signal in the test room to prevent candidates from using communication tools to cheat in the test. Many schools responded that after turning on the mobile phone signal jammer, it interfered with the campus broadcast to a certain extent. In some areas, the broadcast signal interference was serious. After turning off the mobile phone signal jammer, the interference will disappear. Let's talk about the cause of this The reason for the situation, and how to fix it.
First of all, campus radio is a kind of low-power FM radio. Many colleges and universities, middle schools and even Xiaoxue have now adopted a large number of campus FM radios to broadcast English programs or other programs, and the frequency range is usually between 76-88MHz. The signal emitted by the mobile phone signal jammer is a white noise interference signal with the same frequency as that used by the mobile phone. The lowest frequency band is the 700M radio and television 5G frequency band, which is not the same as the signal frequency of the campus broadcast, and it can even be said to be very different. The reason for the interference to the campus broadcast signal is likely to be that after the mobile phone signal jammer is turned on, the bottom noise in the test room is increased in some areas. This bottom noise drowns the campus broadcast signal, so the broadcast signal is disturbed. So how to solve it?
1. Adjust the transmission frequency of campus radio, and conduct interference test to find out the use of campus radio frequency band with the least interference.
2. If it is not possible to find the campus broadcast frequency band with the least interference, the mobile phone signal jammer should not be turned on during the listening test, and the signal jammer should be turned on after the listening test.