Very high frequency (VHF) is the radio frequency range from 30 MHz (wavelength 10 m) to 300 MHz (wavelength 1 m).
Common uses for VHF are FM radio broadcast at 88-108 MHz and television broadcast (together with UHF). VHF is also commonly used for terrestrial navigation systems (VOR in particular) and aircraft communications.
The general description of frequencies immediately below VHF is HF, and the next higher frequencies as known as Ultra high frequency (UHF). UHF and VHF are the most common frequency bands for television.
VHF frequencies' propagation characteristics are ideal for
short-distance terrestrial communication. Unlike high frequencies (HF), the
ionosphere does not usually reflect VHF radio and thus transmissions are restricted to the local area (and can't interfere with transmissions thousands of kilometres away) It is also less affected by atmospheric noise and interference from electrical equipment than low frequencies. Whilst
it is more easily blocked by land features than HF and lower
frequencies, it is less bothered by buildings and other less
substantial objects than higher frequencies. It was also easier to
construct efficient transmitters, receivers, and antennas for it in
the earlier days of radio.
In most countries, the VHF spectrum is used for broadcast audio and
television, as well as commercial two-way radios (such as that
operated by taxis and police), marine two-way audio communications,
and aircraft radios.
The large slice of technically and commercially valuable slice of the
VHF spectrum taken up by television transmission has attracted
the attention of many companies and governments recently, with the
development of more efficient digital television broadcasting
standards. In some countries much of this spectrum will likely
become available (probably for sale) in the next decade or so
(currently scheduled for 2008 in the United States).
In the United Kingdom, the authorities chose to develop colour television exclusively on UHF, beginning in the late 1960s. The last British VHF TV transmitters closed down in 1986. VHF band III is now used in the UK for digital audio broadcasting.
