VHF - Very High Frequency

VHF, Very High Frequency, represents the spectrum of radio waves that extend from 30MHz to 300 MHz with wavelengths from 1 m to 10 m.

What is meant by VHF?

In the common language, VHF is defined as devices that use this frequency spectrum, which are mainly:

Technically, VHF instead means the spectrum of radio waves that extend from 30MHz to 300 MHz and corresponds to the abbreviation of Very High Frequency, or very high frequency.

VHF Propagation

The VHF band uses a spectrum whose propagation takes place mainly in a straight line (also called optical range), or is able to suffer even small obstacles or the curvature of the earth, so it is commonly used for short-distance communications.

In fact, the VHF frequency usually fails to benefit from the refractions of the upper layers of the atmosphere, with the exception of the lower part of this frequency (approximately below 70 MHz), where it is possible to feel the propagation of the ionosphere, especially in periods of intense solar activity.

It can also be affected by the effects of the Northern Lights, the meteo-scatter (ionization of the atmosphere by meteorites) and EME (where the moon is used as a passive satellite), but in these cases the quality of the signal is poor and of major interest to the amateur radio world only.

The frequencies assigned

The VHF spectrum has been internationally assigned frequencies for specific operations, the following are the most popular:

  • From 50 to 51 MHz and from 144 to 146 MHz to the amateur radio world
  • 88 to 108 MHz for FM radio transmission
  • 108 to 118 MHz to VOR aeronautical systems
  • 118 to 136 MHz to aeronautical communications
  • 156 to 174 MHz to maritime services
  • From 177.5 to 226.5 Mhz (band III) to some channels of digital terrestrial (DVB-T)