The shielding distance of the device has a great relationship with the power of the device and the use environment, and several aspects that are helpful to the shielding effect: one is the output power of the device, the other is the working method of the shield, and the third is the use environment (indoor or outdoor). The fourth is to shield the interference intensity of the surrounding environment.
Nowadays, mobile phones are all digital signals, and the anti-interference ability of digital signals is very strong. Generally, the effect of using analog signal technology to interfere with digital signals is poor. Therefore, digital signals must be used to interfere with digital signals. The interference effect is quite different. The signal jammer using digital jamming signal technology has lower power and higher efficiency than the jammer using analog signal jamming technology.
The synthesis, attenuation, and reflection analysis of indoor mobile phone signals and interference signals is very complicated. Before shielding, the strength and quality of local cell phone signals have a great impact on shielding. Different mobile phones have different effects. Generally, mobile phones with strong ability to receive weak signals may not have good anti-interference effects.
The direction of the base station and the direction of the shielded area of the mobile phone also affect the shielding effect. Generally, the spatial signal strength is about -60 to -70dbm, and the base station can reach about -40dbm within a few hundred meters, and the mobile phone reception strength range is generally between -35 to -95dbm. The higher the signal power of the space mobile phone, the shorter the shielding distance.
The above conclusions are based on the law of radio signal transmission in free space. In reality, there are many obstacles on the ground that affect the transmission of radio waves. The above can only be qualitatively used as a reference, especially indoors. The above law is very different from the actual situation. Therefore, this problem is difficult to calculate accurately at the time, and can only be determined based on the actual situation on site. Precise construction projects must carry out preliminary research and signal testing, and then design specific solutions. In the later period, timely follow-up tests are required, and certain corresponding supplements can be foolproof, that is, to achieve the effect of strict shielding.