Very High Frequency
Very high frequency (VHF) is the ITU-designated range of radio frequency electromagnetic waves from 30 MHz to 300 MHz. Frequencies immediately below VHF are denoted high frequency (HF), and the next higher frequencies are known as ultra high frequency (UHF).
These names referring to frequency usage originate from the early 20th century, when regular radio service used the terms LF (low frequencies), MF (medium frequencies), and HF (high frequencies). These names were standardized by the International Telecommunications Union (ITU) and extended to higher frequency ranges.
Common uses for VHF are FM radio broadcasting, television broadcasting, land mobile stations (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.
Read more about Very High Frequency: Propagation Characteristics, Line-of-sight Calculation, Universal Use, Unlicensed Operation
Famous quotes containing the words high and/or frequency:
“From low to high doth dissolution climb,
And sink from high to low, along a scale
Of awful notes, whose concord shall not fail;”
—William Wordsworth (1770–1850)
“One is apt to be discouraged by the frequency with which Mr. Hardy has persuaded himself that a macabre subject is a poem in itself; that, if there be enough of death and the tomb in one’s theme, it needs no translation into art, the bold statement of it being sufficient.”
—Rebecca West (1892–1983)