The working principle of wireless signal jammers
The working principle of mobile communication is that within a certain frequency range, wireless devices (mobile phones, etc.) and base stations communicate through radio waves to complete data and sound transmission with a certain baud rate and modulation method. When the mobile phone communicates, it contacts the base station through the uplink frequency, and then transfers the signal to the mobile service switching center to realize the call. In the standby state, the mobile phone communicates with the base station through the broadcast control channel. Once there is a need for a call, the mobile phone will first be assigned to the mobile phone business channel according to the specific conditions of the channel near the terminal through the request, so that the mobile phone will jump to the business channel to realize the call and data transmission. . At the same time, wireless communication must ensure sufficient signal-to-noise ratio to effectively receive and complete the communication.
According to the above working principle, the mobile phone signal jammer is generally composed of power supply, electronic scanning control unit, segmented radio frequency module unit, amplifier unit, transmitting antenna unit and other parts. After the signal generator generates the scanning signal, it goes through the inverter, enters the oscillator and modulates it to the mobile communication working frequency band, and then is amplified by the power amplifier and the voltage regulator tube controls the power. The amplified frequency scanning signal is transmitted into the air in the form of radio waves. Because the frequency sweep signal forms garbled interference in the message signal received by the mobile phone, the mobile phone cannot receive the normal data sent by the base station, so that the mobile phone cannot establish a normal connection with the base station, so that the mobile phone is disconnected from the base station communication network. The mobile phone shows the phenomenon that the search network has no signal, no service system, etc., to achieve the blocking effect.
The interference power of the shield is fixed, and the shielding radius of the unobstructed space is determined by the path attenuation and the signal level of the receiving base station. In order to realize the interference of the mobile phone signal jammer to the mobile network, it must be ensured that the signal field emitted by the jammer is stronger than the field strength of the mobile signal in the interference area. The closer the interference location is to the base station, the stronger the field strength and the smaller the effective interference area, and vice versa. , the farther the interference site is from the base station, the weaker the field strength and the larger the effective interference area.
It can be seen that within a certain transmission power, the interference range depends on the field strength in the interference area. No matter how powerful the shield is, as long as the transmission power is constant, as the distance increases, the strength of the interference signal will gradually attenuate, thereby losing Interference ability. The output channel power of the masker, the signal level of the base station, and the gain of the coverage line can determine the theoretical coverage radius with reference value.