ITWissen.info - Tech know how online

very high frequency (VHF)

Very High Frequency (VHF) is the frequency range between 30 MHz and 300 MHz. These frequencies correspond to wavelengths of 10 m to 1 m. At the International Telecommunication Union( ITU), the VHF band has the band number 8, which is mathematically related to the frequency band.

VHF is used for terrestrial transmissions. For example, for fixed and mobile telephony and, above all, for FM broadcasting and television, Band I between 47 MHz and 68 MHz and Band III between 174 MHz and 230 MHz. In America, Band I occupies the frequency range between 54 MHz and 72 MHz and Band III the frequencies between 174 MHz and 216 MHz. In some countries, the bandwidth is 8 MHz. This is the case for SECAM, which is transmitted in France and in Eastern Europe.

Frequency bands of the ITU

Frequency bands of the ITU

Band III contains the eight 7 MHz channels 5 to 12, which are used for analog television, digital TV and digital radio. For digital audio broadcasting( DAB), the channels can be divided into four subchannels each with a bandwidth of 1.75 MHz. After switching off terrestrial TV, Band III will be used for Digital Video Broadcast.

Channel grid of Band III for analog television, DVB and DAB

Channel grid of Band III for analog television, DVB and DAB

Between the two frequency bands mentioned above lies Band II for FM broadcasting with frequencies between 88 MHz and 108 MHz. This frequency band is divided into channels with 200 kHz bandwidth. The frequencies for the FM and TV bands are identical for terrestrial transmission and in cable distribution networks.

Above the VHF broadcasting band between 108 MHz and 118 MHz are the radio frequencies for air navigation, and above that in the frequency ranges from 118 MHz to 144 MHz and 230 MHz to 400 MHz are the VHF airborne radio frequencies. The frequency range of 174 MHz and 223 MHz is also approved for radio microphones, among other things.

Informations:
Englisch: very high frequency - VHF
Updated at: 11.04.2014
#Words: 285
Links: frequency (f), megahertz (MHz), international telecommunication union (ITU), frequency band, terrestrial
Translations: DE
Sharing:    

All rights reserved DATACOM Buchverlag GmbH © 2022