前言自四十年代以来,短波通信一直是远距离通信的主要工具之一。它具有通信距离远、设备简单、成本低等优点,因而它在通信技术中一直占有极为重要的地位,成为一种十分重要的通信手段。但是,卫星通信问世以后,不少短波通信业务为卫星通信所代替,因此,人们对它的作用和发展前途曾展开了长时间的争论,似乎短波通信可完全由 Preface Since the 1940s, shortwave communications have been one of the major tools for long-distance communications. It has the advantages of long distance communication, simple equipment and low cost. Therefore, it has always occupied a very important position in communication technology and has become a very important means of communication. However, after the advent of satellite communications, many shortwave communications services have been replaced by satellite communications. As a result, people have been debating their role and future development for a long time. It seems that shortwave communications can be completely