无线电通信的最大优点是设备操作使用灵活、方便,而其最大的缺点就是容易受到干扰。人们在日常生活中感受最多的无线电干扰就是听收音机时出现“喀啦”声和看电视时屏幕上出现“雪花”,但这些都是小事。有些无线电干扰还会造成严重的后果,甚至给人民的生命安全带来威胁。去年我国民航机场的通信导航系统多次受到干扰,迫使机场不得不暂时关闭,飞机只能飞到其它机场降落,直接影响到人们的正常生活和工作。事后发现干扰是来自一些选址不当、发射设备不符合国家标准的寻呼台,由于这些寻呼台发射功率过大、天线之间距离过近,形成互调干扰影响了机场的通信导航设备。 1.无线电干扰的种类与等级 无线电干扰发生在无线电频谱内。当接收机收到无用信号 The biggest advantage of radio communication equipment operation and use of flexible, convenient, but its biggest drawback is easily interfered with. The radio interference people feel most in daily life is the “click” sound when listening to the radio and the “snowflake” on the screen when watching TV, but these are trivial matters. Some radio interference can have serious consequences and even threaten the safety of people’s lives. Last year, the communications and navigation system of China’s civil airport was repeatedly disturbed, forcing the airport to temporarily shut down. The aircraft only flew to other airports for landing, which directly affected people’s normal life and work. Afterwards, it was found that the interference came from some paging stations that were not properly located and whose transmitting equipment did not meet the national standards. As the transmitting power of these paging stations is too large and the distance between the antennas is too close, intermodulation interference affects the airport’s communications and navigation equipment. 1. Types and levels of radio interference Radio interference occurs in the radio frequency spectrum. When the receiver receives a useless signal