The two transpolar shortwave time signal circuits,Moscow and Irkutsk to the Great Wall Station in Antarctica, are used to study the fading characters for shortwave long circuit.

为了研究过短波长电路特性，在南长城站收测莫斯科、依尔茨克短波授时台信号，并给出各频对应深度、、平均持续时间等参数统计特征和幅度分布曲线。