| Following the rapid development of science and technology and modern wireless communication technology, the demand for wireless communication is getting more and more intense. Moreover, further importance is being attached to the electromagnetic radiation created by the radio communication during a transmission launch. This article brings to light the influence of electromagnetic radiation pollution on the surrounding facilities, as well as the state administration of radio, wireless radio administration specific construction projects, depending on actual use in various transmitter and the characteristics of all kinds of antenna as the starting point. Using the theory of electromagnetic waves and electromagnetic fields, the calculation method of short wave antenna, medium wave antenna can be established, and the feasibility and effectiveness of the calculation can be verified with testing. The paper studies the frequency, electrical conductivity and other factors that effect electric field intensity. Finally, the paper, combined with the actual situation, analyzes the electromagnetic interference phenomenon while the transmitting antenna is functioning.Using the two methods of the theoretical calculation and practical testing, we found that the electric field strength or power density around the middle, short wave antenna is changing constantly, they both decrease with the increasing of the distance between the actual position and the antenna.At the distance closest to the antenna, the electric field strength or power density decreases rapidly with the increasing of the distance, followed by a slow and stable decrease in speed.When the medium wave works on the multi-tower multi-frequency mode, the electric field strength shows ladder shape attenuation, it decreases quickly at close range, when increasing the distance, the value of the field strength attenuation becomes slowerFurthermore, practical tests and theoretical calculations show that the launch frequency, while the short wave antenna is functioning, the ground conductivity of its area and dielectric constant all have a certain influence to the geographical size and distribution of the electric field strength around the antenna.The higher the frequency, the higher the near-field region of the field strength values, and the faster the rate of decay of the strength of the electric field. Moreover, the smaller the conductivity and dielectric constant, the greater the strength of the electric field.In addition, the actual situation shows that there is a certain degree of interference of the short-wave high-harmonic generation of electromagnetic on the electronic equipments of the launch pad area, as well as TVs and telephones in the homes of nearby residents.What's more, the actual situation shows that there is a certain degree of interference.The interference on electronic equipments is mainly due to the radiation interference of the secondary circuit of the power system, whereas the interference on TVs is the of a low frequency, caused by the higher harmonic. To suppress the interference, we need to take the source of interference, the transmission way, and disturbance of equipment into consideration.The paper, combining with the reality of actual application taking the high power, short wave radio television launching pad as an example, fully analyzes its reasons, coverage and electric field strength.Furthermore, the variation range of the electromagnetic field strength in the transmitting coverage area with different broadcast frequency is analyzed, the surrounding electromagnetic environment effects from the antenna of the medium, short wave launch pad and solutions are found. Moreover, it has a practical significance on electromagnetic environment influence evaluation. |
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