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 (MHz). It is primarily used for
radio and
television 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
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 405-line television; 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 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, versus 20 kW or less on
VHF Band I) has meant that many US broadcasters elected to move their full-power
ATSC stations from
UHF frequencies to Band III
VHF when all full-power
NTSC analog television 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