Band III is the name of the range of
radio frequencies within the
very high frequency (VHF) part of the
electromagnetic spectrum
The electromagnetic spectrum is the full range of electromagnetic radiation, organized by frequency or wavelength. The spectrum is divided into separate bands, with different names for the electromagnetic waves within each band. From low to high ...
from 174 to 240
megahertz
The hertz (symbol: Hz) is the unit of frequency in the International System of Units (SI), often described as being equivalent to one event (or cycle) per second. The hertz is an SI derived unit whose formal expression in terms of SI base ...
(MHz). It is primarily used for
radio
Radio is the technology of communicating using radio waves. Radio waves are electromagnetic waves of frequency between 3 hertz (Hz) and 300 gigahertz (GHz). They are generated by an electronic device called a transmitter connec ...
and
television
Television (TV) is a telecommunication medium for transmitting moving images and sound. Additionally, the term can refer to a physical television set rather than the medium of transmission. Television is a mass medium for advertising, ...
broadcasting. It is also called high-band VHF, in contrast to Bands
I and
II.
Broadcast Television
North America
The band is subdivided into seven channels for television broadcasting, each occupying 6 MHz.
Europe
European Band III allocations vary from country to country, with channel widths of 7 or 8 MHz.
The standard channel allocations for European countries that use
System B with 7 MHz channel spacing are as follows:
The
Irish (8 MHz) system is shown below.
Oceania
Australia
Australia, officially the Commonwealth of Australia, is a country comprising mainland Australia, the mainland of the Australia (continent), Australian continent, the island of Tasmania and list of islands of Australia, numerous smaller isl ...
has allocated 8 channels in Band III for digital television, each with 7 MHz bandwidth.
Russia and other former members of
OIRT
The International Radio and Television Organisation (official name in French: Organisation Internationale de Radiodiffusion et de Télévision or OIRT (before 1960 International Broadcasting Organization (IBO), official name in French: ''Organ ...
Russian analog television is transmitted using
System D with 8 MHz channel bandwidth.
Radio
The band came into use for radio broadcasting at the turn of the 21st century and is used for ''DAB'' (
Digital Audio Broadcasting
Digital Audio Broadcasting (DAB) is a digital radio international standard, standard for broadcasting digital audio radio services in many countries around the world, defined, supported, marketed and promoted by the WorldDAB organisation. T ...
).
It is subdivided into a number of frequency blocks used for
multiplexes:
Grayed frequencies aren't used for DAB. Furthermore, some countries like Germany don't use channel 13's frequencies to prevent interference with aviation frequencies.
Worldwide usage
Europe
In the UK and part of Ireland, Band III was originally used for
monochrome
A monochrome or monochromatic image, object or palette is composed of one color (or values of one color). Images using only shades of grey are called grayscale (typically digital) or black-and-white (typically analog). In physics, mon ...
405-line television
Television (TV) is a telecommunication medium for transmitting moving images and sound. Additionally, the term can refer to a physical television set rather than the medium of transmission. Television is a mass medium for advertising, ...
; however, this was discontinued by the mid-1980s. Other European countries (including Ireland) continued to use Band III for analogue
625-line colour television.
Digital television in the
DVB-T
DVB-T, short for Digital Video Broadcasting – Terrestrial, is the DVB European-based consortium standard for the broadcast transmission of digital terrestrial television that was first published in 1997 and first broadcast in Singapore in Fe ...
standard can be used in conjunction with VHF Band III and is used as such in some places. The use of sub-band 2 and sub-band 3 band for
Digital Audio Broadcasting
Digital Audio Broadcasting (DAB) is a digital radio international standard, standard for broadcasting digital audio radio services in many countries around the world, defined, supported, marketed and promoted by the WorldDAB organisation. T ...
is now being widely adopted. Sub-band 1 is used for MPT-1327 trunked PMR radio, remote wireless microphones and PMSE links.
North America
In North America, use of the band for television broadcasts is still widespread. Favorable propagation characteristics and reasonable power limits (up to 65
kW for
full-power digital television
Digital television (DTV) is the transmission of television signals using Digital signal, digital encoding, in contrast to the earlier analog television technology which used analog signals. At the time of its development it was considered an ...
, versus 20 kW or less on
VHF Band I
Band I is a range of radio frequencies within the very high frequency (VHF) part of the electromagnetic spectrum. The first time there was defined "for simplicity" in Annex 1 of "Final acts of the European Broadcasting Conference in the VHF and ...
) has meant that many US broadcasters elected to move their full-power
ATSC stations from
UHF
Ultra high frequency (UHF) is the ITU designation for radio frequencies in the range between 300 megahertz (MHz) and 3 gigahertz (GHz), also known as the decimetre band as the wavelengths range from one meter to one tenth of a meter ...
frequencies to Band III
VHF when all full-power
NTSC
NTSC (from National Television System Committee) is the first American standard for analog television, published and adopted in 1941. In 1961, it was assigned the designation System M. It is also known as EIA standard 170.
In 1953, a second ...
analog television
Analog television is the original television technology that uses analog signals to transmit video and audio. In an analog television broadcast, the brightness, colors and sound are represented by amplitude, instantaneous phase and frequency, ...
services in the US shut down in 2009.
Amateur (Ham) Radio has a small allocation of the band, known as the 1.25meter band, from 219 to 220MHz and 222.0 to 225.0MHz for communications.
References
{{Audio broadcasting
Broadcast engineering
Radio spectrum