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Very high frequency (VHF) is the ITU designation for the range of radio frequency electromagnetic waves from 30 to 300 megahertz (MHz), with corresponding wavelengths of ten meters to one meter. Frequencies immediately below VHF are denoted high frequency (HF), and the next higher frequencies are known as ultra high frequency (UHF).
Medium wave (MW) is the part of the medium frequency (MF) radio band used mainly for AM radio broadcasting. The spectrum provides about 120 channels with more limited sound quality than FM stations on the FM broadcast band. During the daytime, reception is usually limited to more local stations, though this is dependent on the signal conditions and quality of radio receiver used. Improved signal propagation at night allows the reception of much longer distance signals. This can cause increased interference because on most channels multiple transmitters operate simultaneously worldwide. In addition, amplitude modulation (AM) is often more prone to interference by various electronic devices, especially power supplies and computers. Strong transmitters cover larger areas than on the FM broadcast band but require more energy and longer antennas. Digital modes are possible but have not reached momentum yet.
Radio broadcasting is the broadcasting of audio (sound), sometimes with related metadata, by radio waves to radio receivers belonging to a public audience. In terrestrial radio broadcasting the radio waves are broadcast by a land-based radio station, while in satellite radio the radio waves are broadcast by a satellite in Earth orbit. To receive the content the listener must have a broadcast radio receiver (radio). Stations are often affiliated with a radio network that provides content in a common radio format, either in broadcast syndication or simulcast, or both. Radio stations broadcast with several different types of modulation: AM radio stations transmit in AM, FM radio stations transmit in FM, which are older analog audio standards, while newer digital radio stations transmit in several digital audio standards: DAB, HD radio, DRM. Television broadcasting is a separate service that also uses radio frequencies to broadcast television (video) signals.
Terrestrial television or over-the-air television (OTA) is a type of television broadcasting in which the signal transmission occurs via radio waves from the terrestrial (Earth-based) transmitter of a TV station to a TV receiver having an antenna. The term terrestrial is more common in Europe and Latin America, while in Canada and the United States it is called over-the-air or simply broadcast. This type of TV broadcast is distinguished from newer technologies, such as satellite television, in which the signal is transmitted to the receiver from an overhead satellite; cable television, in which the signal is carried to the receiver through a cable; and Internet Protocol television, in which the signal is received over an Internet stream or on a network utilizing the Internet Protocol. Terrestrial television stations broadcast on television channels with frequencies between about 52 and 600 MHz in the VHF and UHF bands. Since radio waves in these bands travel by line of sight, reception is generally limited by the visual horizon to distances of 64–97 kilometres (40–60 mi), although under better conditions and with tropospheric ducting, signals can sometimes be received hundreds of kilometers distant.
The FM broadcast band is a range of radio frequencies used for FM broadcasting by radio stations. The range of frequencies used differs between different parts of the world. In Europe and Africa and in Australia and New Zealand, it spans from 87.5 to 108 megahertz (MHz) - also known as VHF Band II - while in the Americas it ranges from 88 to 108 MHz. The FM broadcast band in Japan uses 76 to 95 MHz, and in Brazil, 76 to 108 MHz. The International Radio and Television Organisation (OIRT) band in Eastern Europe is from 65.9 to 74.0 MHz, although these countries now primarily use the 87.5 to 108 MHz band, as in the case of Russia. Some other countries have already discontinued the OIRT band and have changed to the 87.5 to 108 MHz band.
Digital Radio Mondiale is a set of digital audio broadcasting technologies designed to work over the bands currently used for analogue radio broadcasting including AM broadcasting—particularly shortwave—and FM broadcasting. DRM is more spectrally efficient than AM and FM, allowing more stations, at higher quality, into a given amount of bandwidth, using xHE-AAC audio coding format. Various other MPEG-4 codecs and Opus are also compatible, but the standard now specifies xHE-AAC.
BBC Radio Leeds is the BBC's local radio station serving the county of West Yorkshire.
BBC Radio Sheffield is the BBC's local radio station serving South Yorkshire and north Derbyshire.
The Crystal Palace transmitting station, officially known as Arqiva Crystal Palace, is a broadcasting and telecommunications site in the Crystal Palace area of the London Borough of Bromley, England. It is located on the site of the former television station and transmitter operated by John Logie Baird from 1933.
The Sutton Coldfield transmitting station is a broadcasting and telecommunications facility located in Sutton Coldfield, Birmingham, England. In terms of population covered, it is the third most important transmitter in the UK, after Crystal Palace in London and Winter Hill near Bolton.
FM broadcasting is a method of radio broadcasting that uses frequency modulation (FM) of the radio broadcast carrier wave. Invented in 1933 by American engineer Edwin Armstrong, wide-band FM is used worldwide to transmit high-fidelity sound over broadcast radio. FM broadcasting offers higher fidelity—more accurate reproduction of the original program sound—than other broadcasting techniques, such as AM broadcasting. It is also less susceptible to common forms of interference, having less static and popping sounds than are often heard on AM. Therefore, FM is used for most broadcasts of music and general audio. FM radio stations use the very high frequency range of radio frequencies.
The Arfon transmitting station is a facility for FM, DAB digital radio and television transmission near the villages of Nebo and Nasareth in Gwynedd, northwestern Wales. It includes a 308.5 m (1,012 ft) guyed mast with antennas attached at various heights. The mast is surmounted by a television transmitting antenna, which brings the total height of the structure to 317.4 m (1,041 ft), making it the tallest structure in Wales. It is owned and operated by Arqiva.
The Woofferton transmitting station is owned and operated by Encompass Digital Media, as one of the BBC's assets which were handed over as part of the privatization of World Service distribution and transmission in 1997. It is the last remaining UK shortwave broadcasting site, located at Woofferton, south of Ludlow, Shropshire, England. The large site spreads across into neighbouring Herefordshire.
The Oxford transmitting station is a broadcasting and telecommunications facility, situated on land 129.5 metres (425 ft) above Ordnance Datum to the north east of the city of Oxford, in Oxfordshire, England. It has a guyed steel lattice mast which is 154.4 metres (507 ft) in height to the top of the main steel structure. The UHF television antenna, which consist of a vertical array of transmitting panels, is mounted above the steel structure. The total height of the mast to the top of this UHF antenna is 165.7 metres (544 ft). It is owned and operated by Arqiva.
The Haverfordwest transmitting station is a broadcasting and telecommunications facility located at Woodstock about 13 km (8 mi) to the north east of the town of Haverfordwest, in Pembrokeshire, Wales. It was originally built by the BBC, entering service in early 1964 acting as a main transmitter for the 405-line VHF television system, and as a repeater for Band 2 VHF FM radio received off-air from Blaenplwyf transmitting station. It is now owned and operated by Arqiva.
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 UHF bands - Stockholm, 1961". Band I ranges from 47 to 68 MHz for the European Broadcasting Area, and from 54 to 88 MHz for the Americas and it is primarily used for television broadcasting in compliance with ITU Radio Regulations. With the transition to digital TV, most Band I transmitters have already been switched off.
Television frequency allocation has evolved since the start of television in Australia in 1956, and later in New Zealand in 1960. There was no coordination between the national spectrum management authorities in either country to establish the frequency allocations. The management of the spectrum in both countries is largely the product of their economical and political situation. New Zealand didn't start to develop television service until 1965 due to World War 2 and its economic harm in the country's economy.
Radio jamming on the Korean Peninsula makes the border region one of the world's busiest places for radio signals. Medium wave jamming is dominant in the area including Seoul and the Korean Demilitarized Zone (DMZ). South Korea jams all radio and television broadcasts from North Korea, and until 2013 jammed all foreign broadcasts, which was ended during the Park Geun-hye administration.
BBC Radio Sussex is the BBC's local radio station serving the county of Sussex.
The Kilvey Hill transmitting station was originally built at the summit of Kilvey Hill in Swansea, Wales, by the BBC in 1967 as a relay for VHF and UHF television. VHF television came on air a few months before the UHF services. As built, the station did not radiate VHF FM radio, this was added later. Currently, the hill's transmitters cater for viewers and listeners in the Swansea and Neath Port Talbot area. The transmission station located on top of Kilvey Hill is owned and operated by Arqiva.
References
- ↑ List of radio stations in the United Kingdom
- ↑ "VHF Broadcast Re-planning Final Report". 2 June 2000. Retrieved 4 September 2008.
- ↑ "Boost for commercial analogue radio stations". gov.uk. Retrieved 5 July 2020.
