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Very high frequency (VHF) is the ITU designation〔(【引用サイトリンク】url=http://www.itu.int/dms_pubrec/itu-r/rec/v/R-REC-V.431-7-200005-I!!PDF-E.pdf )〕 for the range of radio frequency electromagnetic waves (radio waves) from to , with corresponding wavelengths of ten to one meters. Frequencies immediately below VHF are denoted high frequency (HF), and the next higher frequencies are known as ultra high frequency (UHF). Common uses for VHF are FM radio broadcasting, television broadcasting, two way land mobile radio systems (emergency, business, private use and military), long range data communication up to several tens of kilometres with radio modems, amateur radio, and marine communications. Air traffic control communications and air navigation systems (e.g. VOR, DME & ILS) work at distances of 100 kilometres or more to aircraft at cruising altitude. VHF was used for analog television stations in the US, and continues to be used for digital television. ==Propagation characteristics== VHF propagation characteristics are suited for short-distance terrestrial communication, with a range generally somewhat farther than line-of-sight from the transmitter (see formula below). * VHF waves are restricted to the local radio horizon less than 100 miles. * VHF is less affected by atmospheric noise and interference from electrical equipment than lower frequencies. * While it is blocked by land features such as hills and mountains, it is less affected by buildings and can be received indoors, although multipath television reception due to reflection from buildings can be a problem in urban areas. * Unlike high frequencies (HF), the ionosphere does not usually reflect VHF waves (called skywave propagation). * VHF waves can be aided by tropospheric ducting 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「Very high frequency」の詳細全文を読む スポンサード リンク
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