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前言在短波传播中,电波由发射点经电离层反射到达地面。由于地面的地形的不平和电气特性的不均匀,电波在地面上散射,部分散射的能量将循原路径再次经电离层反射到发射点,观测这种后向散射信号的方法,称为斜向返回探测。利用斜向返回探测,可以实时地确定某频率的跳距和一定距离的最高可用频率,这已为大量的实验所证实(见《武汉大学学报》自然科学版1975年第3期)。因此,它在协助通讯人员选择频率方面,是极为有力的工具;同时,
Introduction In the shortwave propagation, the electric wave arrives at the ground from the launch point through ionospheric reflection. Because of uneven terrain and uneven electrical characteristics, radio waves scatter on the ground, and part of the scattered energy will follow the original path and be reflected again by the ionosphere to the emission point. The method of observing this backscattered signal is called oblique Return to probe. The use of oblique return detection, in real time to determine the frequency hopping and a certain distance of the maximum available frequency, which has been confirmed by a large number of experiments (see "Wuhan University, Natural Science Edition, No. 3, 1975). Therefore, it is an extremely powerful tool in assisting communications personnel in selecting frequencies; at the same time,