Several parameters useful for the signal jammer effect of mobile phones:
①Screen output power
② Antenna radiation performance (antenna gain, directivity, etc.)
2.Working method of shielding
Nowadays, mobile phones are all digital signals, so the anti-shielding ability of digital signals is very strong. In general, analog signal technology is not very effective in protecting digital signals. Therefore, digital signals should be used to protect digital signals. For mobile phones, use shielded digital signals and shielded analog signals with the same power. The shielding effect is very different. Displays using digital signal shielding technology have lower power consumption and higher efficiency than displays using analog signal wave scramblers.
3.inside and outside are different
The synthesis, attenuation and reflection analysis of the internal signal and the shielding signal of the mobile phone is very complicated.
Before being shielded, the strength and quality of the cell phone’s signal in the local space will have a significant impact on the shielding. Different mobile phones have different effects. In general, cell phones with poor signal reception may not have good anti-shielding effects.
The direction and distance from the signal source and the direction of the cell phone’s shielding area will also affect the shielding effect.
The characteristics of shielding distance and radio signal transmission distance. However, the shielding distance is briefly discussed by the attenuation of the radio signal emitted in free space. According to the transmission theory formula, every time the radio wave transmission distance doubles, the signal strength will be attenuated by 6dB (the signal strength will be reduced by 4 times). Take the example of the 900MHZ GSM cellular signal wifi jammer. If the cell phone signal strength in the protected area is -50 dBm and the effective shielding distance of the jammer is 10 meters, the change in the cell phone signal strength will directly affect the distance, please refer to the following table:
Note: dbm is the abbreviation of dbmw, which stands for the unit of power of radio equipment or signals, namely the decibel milliwatts
① The general spatial signal strength is -60 to -70 dBm, the base station can reach -40 dBm within a few hundred meters, and the receiving power range of the mobile phone is generally -35 to -95 dBm.
② The higher the spatial strength of the mobile phone signal, the shorter the shielding distance.