We all know that during the college entrance examination every year, the school will have problems with mobile phones dropping, mobile phones can not access the Internet, and the network speed near the test center is slow. This is because the school has opened a wifi jammer. If we think of the phone as a handheld two-way radio, the radio can be disturbed, then the phone is no exception, and the signal of the phone will be disturbed.
Interfering with a mobile phone is just like interfering with other types of radio communication. The mobile phone is connected to its service network through the base station. When the mobile phone user drives along the street, the mobile phone signal will be switched from one base station to another. That is to say, in the course of our daily movement, the mobile phone we carry with us is constantly switching to connect with ourselves. Base station.
Wireless communication uses electromagnetic waves for communication. Its functional characteristics are determined by its frequency. Therefore, if our telephone is to be connected to the network smoothly and communicates normally, it must send out the required electromagnetic waves to connect to our communication carrier base station. . Of course, different communication systems use different frequencies so that everyone does not interfere with each other.
The mobile interference device works by transmitting the same radio wave signal as the mobile phone. Because the frequency is the same, the mobile phone can't distinguish which signal is the regular base station signal, thus achieving the "interference signal". When the base station tries to connect to the phone, it will emit a lot of "noise", which causes the signal of the mobile phone to be unrecognizable, so we can't use it normally. Mobile communication.
In the early days, the jammer only blocked a set of frequencies, such as GSM, which is what we usually call 2G networks, and complex jammers can block several types of networks at the same time, such as 2G 3G 4G WIFI Bluetooth GPS signals, that is to say The interference band corresponding to these signals is repeated in a cyclical manner, and the interval of this cycle is so small that the mobile phone has no chance to speak and can only sit down.
According to extensive reports, in December 2003, a wifi jammer thwarted the assassination attempt of Pakistani President Pervez Musharraf. The British police have considered using jammers to protect the president's team in London. In the anti-drug operation, the police can intercept the phone so that the suspect cannot be contacted outside the area.
The main principle of cell phone signal shielding and wifi signal jammer is to emit huge noise in the frequency band used by the mobile phone, which interferes with the reception and transmission of the normal signal of the mobile phone. This small object is not only often used to prevent cheating in exams, but is also used politically and militarily to prevent terrorist attacks. But the signal jammer is not like shopping for food, it is not casually purchased and used, otherwise it may involve illegality.