Ultra high frequency (UHF) designates a range (band) of electromagnetic waves with frequencies between 300 MHz and 3 GHz (3,000 MHz). A band is a small section of the spectrum of Radio communication frequencies, in which channels are usually used or set aside for the same Electromagnetic radiation takes the form of self-propagating Waves in a Vacuum or in Matter. A wave is a disturbance that propagates through Space and Time, usually with transference of Energy. Frequency is a measure of the number of occurrences of a repeating event per unit Time. The hertz (symbol Hz) is a measure of Frequency, informally defined as the number of events occurring per Second. The hertz (symbol Hz) is a measure of Frequency, informally defined as the number of events occurring per Second. Also known as the decimeter band or decimeter wave as the wavelengths range from ten to one decimeters. A decimetre ( American spelling: decimeter, symbol dm) is a unit of Length in the Metric system, equal to one tenth Radio waves with frequencies above the UHF band fall into the SHF (Super high frequency) and EHF (Extremely high frequency) bands; all of which fall into the Microwave frequency range. Super high frequency (or SHF) refers to radio frequencies (RF in the range of 3  GHz and 30 GHz Extremely high frequency is the highest Radio frequency band. Microwaves are electromagnetic waves with Wavelengths ranging from 1 mm to 1 m or frequencies between 0 Lower frequency signals fall into the VHF (Very high frequency) or lower bands. Very high frequency (VHF is the Radio frequency range from 30 MHz to 300 MHz. See electromagnetic spectrum for a full listing of frequency bands. The electromagnetic (EM spectrum is the range of all possible Electromagnetic radiation frequencies

## Uses

One uncommon use of UHF waves is for the detection of partial discharges. In Electrical engineering, a partial discharge (PD is a localised Dielectric breakdown of a small portion of a solid or liquid Electrical insulation system Partial discharges occur because of the sharp geometries created in high voltage insulated equipment. Electrical tension (or voltage after its SI unit, the Volt) is the difference of electrical potential between two points of an electrical The advantage of UHF detection is that this method can be used to localize the source of the discharge. A drawback to UHF detection is the extreme sensitivity to external noise. UHF detection methods are used in the field, especially for large distribution transformers. A transformer is a device that transfers Electrical energy from one circuit to another through inductively coupled Electrical conductors

2. 45 GHz, now mainly used for WiFi, Bluetooth and US cordless phones has been proposed for Wireless energy transfer. Wi-Fi (ˈwaɪfaɪ is the trade name for the popular wireless technology used Bluetooth is a wireless protocol utilizing short-range communications technology facilitating data transmission over short distances from fixed and/or mobile devices creating wireless Wireless energy transfer or wireless power transmission is the process that takes place in any system where Electrical energy is transmitted from a power Some pilot experiments have been performed, but it is not used on a large scale.

Some radio frequency identification (RFID) tags utilize UHF. Radio-frequency identification ( RFID) is an automatic identification method relying on storing and remotely retrieving data using devices called RFID tags or These tags are commonly known as UHFID's or Ultra-HighFID's (Ultra-High Frequency Identification).

The main advantage of UHF transmission is the physically short wave that is produced by the high frequency. The size of transmission and reception equipment, (particularly antennas), is related to the size of the radio wave. An antenna is a Transducer designed to transmit or Receive electromagnetic waves In other words antennas convert electromagnetic waves into Smaller and less conspicuous antennas can be used with higher frequency bands.

## History

### Australia

Australia also provides the UHF CB service for general-purpose two-way communications. UHF CB is a class licensed (meaning Licence -free use for most users Citizen's band Radio service authorised by the

### Ireland

In the Republic of Ireland, UHF was introduced in 1978 to augment the existing RTÉ One VHF 625-line transmissions and to provide extra frequencies for the new RTÉ Two channel. Ireland ( Irish: Éire, ˈeːrʲə is a country in north-western Europe. RTÉ One (Irish RTÉ a hAon) is the Republic of Ireland 's oldest and most popular Television channel operated by Irish state broadcaster Radio Telefís RTÉ Two (Irish RTÉ a Dó) (known from 1988 to 2004 as Network 2, RTÉ Network Two, RTÉ2 or N2) is the Republic of Ireland The first UHF transmitter site was Cairn Hill in Co. Longford, followed by Three Rock Mountain in South Co. Dublin. County Longford (Contae an Longfoirt is a county situated in the Irish Midlands, in northwest Leinster. Three Rock is a 450 metre mountain located in the Dublin Mountains, in the east of Ireland. County Dublin (Contae Bhaile Átha Cliath or more correctly today the Dublin Region ( Réigiúin Átha Cliath) is the area that contains the city of Dublin These sites were followed by Clermont Carn in Co. Louth and Holywell Hill in Co. Donegal in 1981. Clermont Carn, variously spelt as "Clermont Cairn" "Clairmont Carn/Cairn" or other variations is a 510 Metre high mountain in County Louth which County Louth (Contae Lú is a County on the East coast of Ireland, on the border with Northern Ireland. County Donegal (ˌdʌnəˈgɔːl Irish: Contae Dhún na nGall. Elsewhere in Ireland, both the RTÉ channels are available on VHF. Since then RTÉ have migrated nearly all their low-power relay sites to UHF. TV3 and TG4 are transmitted entirely in UHF only. When Digital Terrestrial TV is introduced, it is intended to broadcast this on UHF only initially, although VHF allocations exist. VHF TV is likely to cease whenever the existing analogue broadcasts are switched off. Analog (or analogue) television encodes Television picture and sound information and transmits it as an Analog signal: one in which the The UHF band is also used in parts of Ireland for Television deflector systems bringing British television signals to towns and rural areas which cannot receive these signals directly

### Malaysia

UHF broadcasting was used outside Kuala Lumpur and the Klang Valley by private TV station TV3 in the late 80s, with the government stations only transmitting in VHF (Bands 1 and 3) and the 450 MHz range being occupied by the ATUR cellular phone service operated by Telekom Malaysia. Kuala Lumpur (ˈkwɑːləlʊmˈpʊər Malay /kwɑlɑlʊmpʊ/ and locally /kwɑləlʊmpɔ/ or even /kɔlɔmpɔ/ or often abbreviated as K Klang Valley (Lembah Klang is an area in Malaysia comprising Kuala Lumpur and its suburbs and adjoining cities and towns in the state of Selangor Sistem Televisyen Malaysia Berhad (STMB or TV3 was incorporated in 1983 as Malaysia ’s first commercial Television station. Telekom Malaysia Berhad (TM) is the largest telecommunication company in Malaysia and also Southeast Asia 's second-largest telecommunication company The ATUR service ceased operation in the late 90s, freeing up the frequency for other uses. UHF was not commonly used in the Klang Valley until 1994 (despite TV3's signal also being available over UHF Channel 29, as TV3 transmitted over VHF Channel 12 in the Klang Valley). 1994 saw the introduction of the channel MetroVision (which ceased transmission in 1999, got bought over by TV3's parent company - System Televisyen Malaysia Berhad - and relaunched as 8TV in 2004). 8TV (; literal 8th dimension is a private Malaysian Television station previously known as Metrovision This was followed by Ntv7 in 1998 (also acquired by TV3's parent company in 2005) and recently Channel 9 (which started in 2003, ceased transmission in 2005, was also acquired by TV3's parent company shortly after, and came back as TV9 in early 2006). Natseven TV Sdn Bhd or better known as ntv7 is a Terrestrial television channel in Malaysia. TV9 is a Malaysian private-owned Television station which started transmission on April 22, 2006. At current count, there are 4 distinct UHF signals receivable by an analog TV set in the Klang Valley: Channel 25 (8TV), Channel 29 (TV3 UHF transmission), Channel 37 (NTV7) and Channel 39 (TV9). Channel 35 is usually allocated for VCRs, decoder units (i. e. the ASTRO and MiTV set top boxes) and other devices that have an RF signal generator (i. A set-top box (STB or set-top unit (STU is a device that connects to a Television and an external source of signal, turning the signal into e. game consoles).

### United Kingdom

As a consequence of achieving maximum national coverage, signals from one region would typically over-lap with that of another, which was accommodated for by allocating a different set of channels in each adjacent area, often resulting in greater choice for viewers when a network in one region aired different programmes to the neighbouring region.

Initial uptake of UHF television was very slow: Differing propagation characteristics between VHF and UHF meant new additional transmitters needed to be built, often at different locations to the then-established VHF sites, and generally with a larger number of relay stations to fill the greater number of gaps in coverage that came with the new band. This led to poor picture quality in bad coverage areas, and many years before the service achieved full national coverage. In addition to this, the only exclusively UHF service, BBC2, would run for only a few hours a day and comprised of alternative programming for minority audiences in contrast to the more popularist schedules of BBC1 and ITV. Popularism ( Popolarismo) is a political doctrine conceived by Don Luigi Sturzo, which was the ideological basis for the Italian People's Party However the 1970s saw a large increase in UHF TV viewing, and VHF take a significant decline: The appeal of colour, which was never introduced to VHF (despite preliminary plans to do so in the late 1950s and early 1960s) and the fall in television prices saw most households use a UHF set by the end of that decade. With the second and last VHF television service having launched in 1955, VHF TV was finally decommissioned for good in 1985 with no plans for it to return to use. Year 1955 ( MCMLV) was a Common year starting on Saturday (link displays the 1955 Gregorian calendar) Year 1985 ( MCMLXXXV) was a Common year starting on Tuesday (link displays 1985 Gregorian calendar)

The launch of Channel 5 in 1997 added a fifth national television network to UHF, requiring deviation from the original frequency allocation plan of the early 1960s and the allocation of UHF frequencies previously not used for television (such as UK Channels 35 and 37 which was previously reserved for domestic VCRs requiring an expensive VCR re-tuning programme funded by the new network). Year 1997 ( MCMXCVII) was a Common year starting on Wednesday (link will display full 1997 Gregorian calendar PLEASE BEAR IN MIND THAT THIS IS A GENERAL ARTICLE ABOUT VCRs/VIDEOCASSETTE RECORDERS A lack of capacity within the band to accommodate a fifth service with the complex over-lapping led to the fifth and final network having a significantly reduced national coverage compared to the other networks, with reduced picture quality in many areas and the use of wide-band aerials often required.

The launch of digital terrestrial television in 1998 saw the continued use of UHF for television, with six multiplexes allocated for the service, all within the UHF band. Digital terrestrial television in the United Kingdom is made up of over fifty primarily free-to-air television channels (including all the national analogue stations A multiplex or mux (called virtual sub-channel in the United States and Canada) is a group of Digital TV channels that are mixed together However analogue transmissions have been planned to cease completely by 2012 after which time it is uncertain as to whether the vacated capacity will be used for additional digital television services or put into alternative use, such as mobile telecommunications or internet services. Analogue terrestrial television in the United Kingdom is traditionally the method most people in the UK, Channel Islands and the Isle of Man used to receive 2012 ( MMXII) will be a Leap year starting on Sunday of the Gregorian calendar.

### United States

On December 29, 1949, KC2XAK of Bridgeport, Connecticut, became the first UHF television station to operate on a regular daily schedule. Events 1170 - Thomas Becket: Thomas Becket Archbishop of Canterbury is assassinated inside Canterbury Cathedral by followers of King Henry II Year 1949 ( MCMXLIX) was a Common year starting on Saturday (link will display the full calendar of the Gregorian calendar. KC2XAK was the world's first UHF television station It was simply a rebroadcast / Broadcast translator Transmitter of New York City's The first commercially licensed UHF television station on the air was KPTV/Channel 27 (now VHF Channel 12) in Portland, Oregon, on September 18, 1952. KPTV is the Fox television affiliate serving the Portland Oregon metropolitan area Portland is a city located in the Northwestern United States, near the Confluence of the Willamette and Columbia rivers Events 96 - Nerva is proclaimed Roman Emperor after Domitian is assassinated Year 1952 ( MCMLII) was a Leap year starting on Tuesday (link will display full calendar of the Gregorian calendar. The station even used much of the equipment, including the transmitter, from KC2XAK, which was delivered by high-speed freight train.

Hopes that UHF would allow dozens of television stations in every media market were thwarted by poor image frequency rejection in superheterodyne tuners with 45. A media market, broadcast market, media region, designated market area, DMA or simply market is a region where the Population Image frequency: In Radio reception using Heterodyning in the tuning process an undesired Input Frequency that is capable of producing In Electronics, the superheterodyne receiver (also known by its full name the supersonic heterodyne receiver, or by the abbreviated form superhet) is a 75 MHz intermediate frequency. In communications and Electronic engineering, an intermediate frequency ( IF) is a Frequency to which a carrier frequency is shifted as an This shortcoming led to "UHF taboos," which limited each area to only modestly more UHF than VHF stations, despite the much larger number of channels. See [1]

A minority of UHF TV transmitters have no programming or commercial identity of their own, and merely retransmit the signal of a VHF station that owns it, to a smaller area poorly covered by the VHF signal. Such transmitters are called "translators" rather than “stations”.

The Family Radio Service and General Mobile Radio Service use the 462 and 467 MHz areas of the UHF spectrum. The Family Radio Service (FRS is an improved Walkie talkie radio system authorized in the United States since 1996 The General Mobile Radio Service (GMRS is a licensed land-mobile FM UHF Radio service in the United States available for short-distance two-way There is a considerable amount of (legal) unlicensed activity (cordless phones, wireless networking) clustered around 900 MHz and 2. 4 GHz.

In February 2009, as part of the transition from analog to digital over-the-air broadcast of television, the spectrum from 698 MHz to 806 MHz (UHF channels 52-69) will no longer be used for TV broadcasting. Digital television (DTV is the sending and receiving of moving images and sound by discrete ( digital) signals in contrast to the analog signals used by The FCC's scheduled auction for this newly-available spectrum was completed in March 2008. The United States 700 MHz FCC wireless Spectrum auction was started by the FCC on January 24, 2008 for the rights to operate the 700 [2]

## Frequency allocation

### Australia

• UHF Citizens Band: 476. UHF CB is a class licensed (meaning Licence -free use for most users Citizen's band Radio service authorised by the 425–477. 400 MHz

### United Kingdom

• 380–395 MHz: Terrestrial Trunked Radio (TETRA) service for emergency use
• 430–440 MHz: Amateur radio (ham - 70 cm band)
• 606–614 MHz: Protected for radio-astronomy
• 470–862 MHz: TV channels 21–69 (channel 36 used for radar, channel 38 used for radio astronomy, channel 69 used for licenced and licence exempt wireless microphones, channels 31-40 and 63-68 to be released and may be made available for other uses by Ofcom. "TETRA" redirects here For other uses see Tetra (disambiguation TErrestrial Trunked RAdio ( TETRA) (formerly known as Public consultation due December 2006)
• 1240–1316 MHz: Amateur radio (ham - 23 cm band)
• 1880–1900 MHz: DECT Cordless telephone
• 2310–2450 MHz: Amateur radio (ham - 13 cm band)

### United States

A brief summary of some UHF frequency use:

• 300–420 MHz: Government use, including meteorology and federal two-way use
• 420–450 MHz: Government radiolocation and amateur radio (ham - 70 cm band)
• 450–470 MHz: UHF business band, General Mobile Radio Service, and Family Radio Service 2-way "walkie-talkies", public safety
• 470–512 MHz: TV channels 14–20
• 512–698 MHz: TV channels 21–51 (channel 34 used sometimes for radar, channel 37 used for radio astronomy)
• 698–806 MHz: TV channels 52–69 (was auctioned in March 2008; bidders will get full use once conversion to digital TV has been accomplished which is scheduled for February 2009)
• 806–824 MHz: Pagers (formerly TV channels 70–72)
• 824–849 MHz: AMPS A & B franchises, terminal (mobile phone) (formerly TV channels 73–77)
• 849–869 MHz: Public safety 2-way (fire, police, ambulance — formerly TV channels 77–80)
• 869–894 MHz: AMPS A & B franchises, base station (formerly TV channels 80–83) (one translator is still in use on channel 83)
• 902–928 MHz: ISM band: cordless phones and stereo, radio frequency identification, datalinks, amateur radio (33 cm band)