山岳回折
http://www.gxk.jp/elec/musen/1ama/H15/html/H1504A22_.html


https://books.google.co.jp/books?id=A8KMBgAAQBAJ&pg=PA230&lpg=PA230&dq=e+30+gp+利得&source=bl&ots=AH5ceOIJBV&sig=ACfU3U0nCoIZe5lWY2FxNElGPKNvRRNumA&hl=en&sa=X&redir_esc=y#v=onepage&q=e%2030%20gp%20利得&f=false