The larger the output power of the cell phone signal jammer, the better the actual effect, I don't think that is the case. For example, an indoor space is about 350-600 square meters, and a mobile phone signal blocker with an area of 700 square meters should also be selected. Not the more power is about. After all, the output power of the mobile phone signal jammer has the scope of safe output power. Some customers expressed why when the video signal is very close, the equipment of most stores will be shielded and the actual effect is poor, while the actual effect of some stores will be very good. I think the data signal is shielded when the video signal is close. The actual effect is poor, I think the proof material, this kind of store is a reasonable and legal store. Is to follow the safety is the output power category. On the contrary, when the video signal is very close, the actual effect of shielding is very good, and the output power is still large. Special attention should be paid to this kind of equipment, because such equipment has already exceeded the safety output power of all normal applications. Not only will it be harmful to the upstream and downstream video signals, but also has security risks, so customers who buy it should pay special attention. Therefore, the output power of the mobile phone signal jammer is not higher and higher.
There are a number of major parameter challenges that contribute to the actual effect of cell phone signal shielding:
1. Power
①The power of the shield
②Characteristics of wireless antenna radiation (gain, specificity, etc. of wireless antenna)
③Other
Second, the method of shielding at work
Nowadays, mobile phones are all analog signals, and the anti-shielding ability of analog signals is very strong. Usually, the technical effect of shielding analog signals with analog signals is weak. Therefore, it is necessary to use analog signals to shield analog signals, and large numbers of the same output power to shield them. The actual effect of shielding the data signal on the mobile phone is completely different from that in the simulation.
3. The difference between indoor and outdoor
The analysis of the generation, attenuation coefficient and reflection surface of the mobile phone signal in the room and the shielded data signal is more complicated.
4. Before being shielded, the compressive strength and quality of mobile phone signals in the local indoor space will cause great harm to shielding. Different mobile phones have different actual effects. Usually, mobile phones with strong ability to accept weak data signals can resist shielding. The effect may not be good.
5. The orientation and spacing of the video signal and the orientation of the mobile phone shielding area also endanger the actual effect of shielding.
6. The characteristics of shielding distance and wireless telephone data signal transmission distance. Now, the attenuation coefficient of wireless telephone data signal transmission in free space is used to easily discuss shielding distance. According to the basic theoretical relationship of transmission, every time the electromagnetic wave transmission distance doubles, the signal The intensity attenuation coefficient is 6db (the output power of the data signal is reduced by 4 times). Then people take a mobile phone signal jammer GSM 800MHZ as an example. If the mobile phone signal strength in a certain area that must be blocked is -60dbm, and the reasonable shielding distance of the jammer is 12 meters, the change of the mobile phone signal strength will immediately harm the shielding. The distance of the distance is mainly shown in the following table:
Note: dbm is the abbreviation of dbmw, which means the unit of output power intensity of wireless telephone equipment or data signal, that is, sound bevel milliwatts
①Usually the signal strength in indoor space is around -65 to -75dbm, the maximum can exceed -50dbm within a few hundred meters of the mobile base station, and the compressive strength range of mobile phones is usually between -45 and -96dbm.
②The higher the compressive strength of the mobile phone signal output power in the indoor space, the less the shielding distance will be.
The above discussion is the basis for calculating the regularity of wireless phone data signal transmission in free space (to put it bluntly, free space is similar to the space shuttle). In reality, there are many obstacles to the transmission of electromagnetic waves on the road. For reference, especially in the room left and right regularity is vastly different from reality. Therefore, this problem cannot be accurately measured for a while, and can only be confirmed according to the specific situation on the spot. Accurate engineering construction projects must carry out early investigations and data signal detection, and then design the main solutions of the plan, and require immediate tracking and detection in the middle and late stages. Doing the necessary relative filling can ensure prevention before it happens, that is to say, it exceeds the strict requirements. The actual effect of masking.