翻訳と辞書 Words near each other ・ Medoc Mountain State Park ・ Medoc noir ・ Medoc Trail Marathon ・ Medochemie ・ Medog ・ Medog frog ・ Medog horned toad ・ Medohar ・ Medoid ・ Medojevac ・ Medium Term Development Framework ・ Medium term note ・ Medium theory ・ Medium Transport Helicopter Regiment 25 ・ Medium tree finch ・ Medium wave ・ Medium, Rare & Remastered ・ Medium-altitude long-endurance unmanned aerial vehicle ・ Medium-capacity rail transport system ・ Medium-chain acyl-CoA dehydrogenase ・ Medium-chain acyl-coenzyme A dehydrogenase deficiency ・ Medium-chain triglyceride ・ Medium-density fibreboard ・ Medium-density housing ・ Medium-density polyethylene ・ Medium-dependent interface ・ Medium-power talker ・ Medium-range ballistic missile ・ Medium-speed vehicle ・ Medium-tailed brush-furred rat Dictionary Lists mini英和辞書 mini和英辞書 Webster 1913 Latin-English FOLDOC Wikipedia English ウィキペディア

翻訳と辞書　辞書検索 [ 開発暫定版 ] スポンサード リンク Medium wave ： ウィキペディア英語版 Medium wave (詳細はmedium frequency (MF) radio band used mainly for AM radio broadcasting. For Europe the MW band ranges from 526.5 kHz to 1606.5 kHz, using channels spaced every 9 kHz, and in North America an extended MW broadcast band goes from 535 kHz to 1705 kHz, using 10 kHz spaced channels. == Propagation characteristics == Wavelengths in this band are long enough that radio waves are not blocked by buildings and hills and can propagate beyond the horizon following the curvature of the Earth; this is called the groundwave. Practical groundwave reception typically extends to 200–300 miles, with longer distances over terrain with higher ground conductivity, and greatest distances over salt water. Most broadcast stations use groundwave to cover their listening area. Medium waves can also reflect off charged particle layers in the ionosphere and return to Earth at much greater distances; this is called the skywave. At night, especially in winter months and at times of low solar activity, the ionospheric D layer virtually disappears. When this happens, MF radio waves can easily be received many hundreds or even thousands of miles away as the signal will be reflected by the higher F layer. This can allow very long-distance broadcasting, but can also interfere with distant local stations. Due to the limited number of available channels in the MW broadcast band, the same frequencies are re-allocated to different broadcasting stations several hundred miles apart. On nights of good skywave propagation, the skywave signals of distant station may interfere with the signals of local stations on the same frequency. In North America, the North American Radio Broadcasting Agreement (NARBA) sets aside certain channels for nighttime use over extended service areas via skywave by a few specially licensed AM broadcasting stations. These channels are called clear channels, and they are required to broadcast at higher powers of 10 to 50 kW. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Medium wave」の詳細全文を読む スポンサード リンク 翻訳と辞書 : 翻訳のためのインターネットリソース Copyright(C) kotoba.ne.jp 1997-2016. All Rights Reserved.