Diffraction propagation

...It requires a large antenna with a reflector area of ​​100 to several hundred m2, a high-output transmitter of several kW to 10 kW, and a low-noise diversity receiver, but because of the large propagation loss along the way, it is limited to small-capacity communications with 120 or fewer telephone lines or low-quality television signal transmission. Depending on the propagation mechanism, it is divided into tropospheric scattering propagation and diffraction propagation, in which radio waves are hit by mountain ridges and received by diffraction. The former emits radio waves toward the atmosphere above and receives them through scattering caused by the inhomogeneity of the atmosphere, and is the method used most for non-line-of-sight communications. ...

*Some of the terminology explanations that refer to "diffraction propagation" are listed below.

Source | Heibonsha World Encyclopedia 2nd Edition | Information

…100～数百m2の反射鏡面積を有する大型アンテナ，数kWから10kW程度の大出力送信機，低雑音のダイバーシティ受信機などを必要とするが，途中の伝搬損失が大きいため，電話回線数にして120以下の小容量通信または低品質のテレビジョン信号伝送などに限られる。伝搬の機構により，対流圏散乱伝搬と，山岳の稜線などに電波を当て，回折によって電波を受信する回折伝搬に分かれる。前者は上方の大気に向けて電波を発射し，大気の不均一性による散乱現象により電波を受信するもので，見通し外通信はこの方式が多い。…

※「回折伝搬」について言及している用語解説の一部を掲載しています。

出典｜株式会社平凡社世界大百科事典 第２版について | 情報