Several small knowledge about mobile communication base stations and electromagnetic radiation
Electromagnetic radiation is a phenomenon in which electromagnetic energy propagates through space in the form of electromagnetic waves. The earth in which human beings live is itself a large magnetic field, and its surface heat radiation and lightning can generate electromagnetic radiation, and the sun and other planets also continuously generate electromagnetic radiation from outer space. Electromagnetic radiation is a phenomenon in which electromagnetic energy propagates through space in the form of electromagnetic waves. The earth in which human beings live is itself a large magnetic field, and its surface heat radiation and lightning can generate electromagnetic radiation, and the sun and other planets also continuously generate electromagnetic radiation from outer space. The artificial electromagnetic radiation mainly comes from various types of electrical equipment, such as radio and television transmitters, microwaves, radars, mobile phones, wireless walkie-talkies, mobile communication base stations, microwave ovens, magnetic resonance equipment, televisions, computers and so on. When the electromagnetic radiation energy exceeds a certain limit, negative biological effects will gradually appear, which may affect people's physical health. Therefore, it becomes what everyone calls electromagnetic radiation pollution, that is, excessive electromagnetic radiation becomes "electromagnetic pollution." "Electromagnetic radiation" and "electromagnetic pollution" are two different concepts. From the concept of electromagnetic radiation, electromagnetic radiation is actually an energy. Its influence on the environment mainly depends on the strength of energy. The dimensional units of its strength mainly include power density, electric field strength and magnetic induction intensity: Power density: refers to the high-frequency electromagnetic energy received or emitted per unit area and unit area, in watts/meter 2 (W/m2). In the high-frequency electromagnetic radiation environment assessment, the power density is usually microwatts per square centimeter (μW). /cm2) indicates. Magnetic Intensity: Represents the magnetic flux per unit volume and area. It is used to describe the intensity of the energy of a magnetic field. The unit is Tesla or Gauss (T or Gs). The biological effects caused by the electromagnetic radiation energy are related to the intensity of the electromagnetic radiation, the irradiation time, the frequency of the radiation wave, and the physical length of the biological exposure. In order to control electromagnetic pollution to the environment, protect people's health, and promote the development of electromagnetic technology, China has formulated the "National Standard Environmental Electromagnetic Wave Sanitation Standard" and "GB9175-88". The electric field strength V/m and the power density μW/cm2 are usually used as a unit. The Chinese government has always attached importance to the public safety of the public, and has promulgated the "Electromagnetic Radiation Protection Regulations" (GB8702-88). The prescribed electromagnetic radiation limit standard is much stricter than the international standard (see Table 1, usually for the RF section), and the standard limit is determined to be 40 μW/cm2. Internationally, the radiation limit value of the working frequency band (ie, frequency 50 Hz) is usually taken as 0.4 micro Tesla (μT). It can be seen from Table 1 that the public radiation limit standard in China is only 40μW/cm2, which is more than 10 times stricter than the International Non-Ionizing Radiation Committee and EU national standards, and 5 times stricter than the Australian standard. Often, common household appliances have corresponding safety standards. For products that pass the standard test, you can use it with confidence. It can be seen from Table 2 that the electromagnetic radiation value of the indoor radio router at 0.3 meters is roughly equivalent to the electromagnetic radiation value of the mobile base station 10 meters away. Microwave ovens, hair dryers, and mobile phones have large electromagnetic radiation values ​​within the distance of use. The microwave oven has a typical radiation value of 0.3μm/cm2 at a door gap of 0.3μm, which is greater than the first-class standard area limit; the upper limit of the typical value of the radiation at the 0.1m of the hair dryer tuyere is 8.0μT, which is greater than the standard limit [0.4 micro Tesla (μT)]. Is the biological effect caused by the use of hair dryer greater than other electrical appliances? Not necessarily, because the working frequency of the hair dryer is lower than the working frequency of the microwave oven and the mobile phone, it is not necessary to exaggerate the influence of the electromagnetic radiation value of the hair dryer on the human body, and refuse to use the hair dryer. The microwave oven should be at least 1 meter away after opening. Pregnant women and children should try to stay away from the microwave oven. When using the mobile phone, try to make the distance between the head and the mobile phone antenna farther. It is best to use separate headphones and microphones to answer the phone. Do not place household appliances too concentrated, or use them together frequently to avoid exposing yourself to the dangers of overdose radiation. Especially TVs, computers, refrigerators and other appliances should not be placed in the bedroom. When the appliances are suspended, it is best not to leave them in standby mode, because a weaker electromagnetic field can be generated at this time, and radiation accumulation will occur for a long time. From the perspective of meeting the needs of more mobile communication users, telecom operators need to focus on solving the problem of network communication capacity. The more base stations are expanded in the mobile communication network, the smaller the single base station transmission power is, the smaller the coverage is, and the smaller the electromagnetic radiation is. In a certain area, the smaller and denser the cell, the larger the call capacity. The higher the density of the base station, the smaller the power transmitted by the base station. At the same time, the closer to the base station, the lower the mobile phone's transmission power. That is to say, the more the base station is built, the smaller the radiation of the person is affected by the communication device. Ningbo Xingchuangzhi Electric Appliance Co.,Ltd. , https://www.xingchuangzhi.com
Table 1 Public radiation limit standards for some countries and organizations 
Table 2 Electromagnetic radiation values ​​of common household appliances and base stations