The higher the power of the mobile phone signal jammer, the better the effect. In fact, this is not the case. For example, if a space is about 400-500 square meters, it is necessary to choose a cell phone jammer with a shielding area of about 600 square meters. It is not about the greater power. After all, the power of the mobile phone signal jammer has a safe power range. Some customers expressed why the shielding effect of most merchants' machines is poor when the signal source is very close, while the effect of some merchants is very good. In fact, when the signal source is close, the signal shielding effect is poor, which proves that these The merchant is a legitimate merchant. is the power range in compliance with safety regulations. On the contrary, when the signal source is very close, the shielding effect is very good, and the power is good. These machines are good to pay attention to, because such machines have exceeded the safe power of normal use. Not only will it affect the upstream signal source, but also there are security risks, so customers who buy it should pay attention. Therefore, the power of the mobile phone signal jammer is not the bigger the better.
Several parameter questions that are helpful to the mobile phone signal shielding effect:
1. Output power
①The output power of the shield
②The performance of the antenna radiation (the gain, directivity, etc. of the antenna)
2. How Shielding Works
Nowadays, mobile phones are all digital signals. The anti-shielding ability of digital signals is very strong. Generally, analog signal technology is used to shield digital signals. The shielding effect is very different. The shielding device with digital shielding signal technology has lower power and higher efficiency than the shielding device with analog signal shielding technology.
3. Indoors are different from outdoor
The analysis of synthesis, attenuation and reflection of indoor mobile phone signals and shielded signals is very complicated.
4. Before shielding, the strength and quality of mobile phone signals in the local space 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-shielding effects.
5. The direction and distance of the signal source and the direction of the shielded area of the mobile phone also affect the shielding effect.
6. The characteristics of shielding distance and radio signal transmission distance. Now, the shielding distance is briefly discussed in terms of the attenuation of radio signal transmission in free space. According to the transmission theory formula, every time the radio wave transmission distance doubles, the signal strength is attenuated by 6db (the signal power is reduced by 4 times. ). Then we take a mobile phone signal jammer GSM 900MHZ as an example. If the mobile phone signal strength in a certain area to be shielded is -50dbm, and the effective shielding distance of the jammer is 10 meters, the change of the mobile phone signal strength will directly affect the shielding distance. . Note: dbm is the abbreviation of dbmw, which represents the power strength unit of radio equipment or signal, that is, decibel milliwatts
①Generally, the signal strength in space is about -60 to -70dbm, and the maximum can reach about -40dbm within a few hundred meters of the base station. The mobile phone reception strength range is generally between -35 and -95dbm.
②The higher the power of the mobile phone signal in space, the shorter the shielding distance.
The above discussion is based on the conclusion that radio signals are transmitted in free space (the so-called free space is similar to space). In reality, there are many obstacles affecting the transmission of radio waves on the ground. The above conclusions can only be used as a qualitative reference, especially The above rules are very different from the actual indoors. Therefore, this problem is difficult to calculate accurately at the moment, and can only be determined according to the actual situation on site. Precise construction projects must carry out preliminary research and signal testing, and then design specific solutions. In the later stage, timely follow-up testing is required, and certain corresponding supplements can be made to be foolproof, that is, to achieve the effect of strict shielding.