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Ultra high frequency

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"UHF" redirects here. For other uses, seeUHF (disambiguation).
Ultra high frequency
Ultra high frequency (ITU)
Frequency range
300MHzto 3GHz
Wavelength range
1mto 1dm
Related bands
Ultra high frequency (IEEE)
Frequency range
300 MHz to 1 GHz
Wavelength range
1 m to 3 dm
Related bands
Radio bands
ITU
1 (ELF)2 (SLF)3 (ULF)4 (VLF)
5 (LF)6 (MF)7 (HF)8 (VHF)
9 (UHF)10 (SHF)11 (EHF)12 (THF)
EU / NATO / US ECM
IEEE
Other TV and radio

Ultra high frequency(UHF) is theITUdesignation forradio frequenciesin the range between 300megahertz(MHz) and 3gigahertz(GHz), also known as thedecimetre bandas the wavelengths range from one meter to one tenth of a meter (onedecimeter). Radio waves with frequencies above the UHF band fall into thesuper-high frequency(SHF) ormicrowavefrequency range. Lower frequency signals fall into the VHF (very high frequency) or lower bands. UHF radio waves propagate mainly byline of sight;they are blocked by hills and large buildings although the transmission through building walls is strong enough for indoor reception. They are used fortelevision broadcasting,cell phones,satellite communication includingGPS,personal radio servicesincludingWi-FiandBluetooth,walkie-talkies,cordless phones,satellite phones,and numerous other applications.

TheIEEEdefines the UHFradar bandas frequencies between 300 MHz and 1 GHz.[1]Two other IEEE radar bands overlap the ITU UHF band: theL bandbetween 1 and 2 GHz and theS bandbetween 2 and 4 GHz.

UHFtelevision antennaon a residence. This type of antenna, called aYagi–Uda antenna,is widely used at UHF frequencies.

Propagation characteristics[edit]

Main article:Radio propagation

Radio waves in the UHF band travel almost entirely byline-of-sight propagation(LOS) and ground reflection; unlike in theHFband there is little to no reflection from theionosphere(skywavepropagation), orground wave.[2]UHF radio waves are blocked by hills and cannot travel beyond the horizon, but can penetrate foliage and buildings for indoor reception. Since thewavelengthsof UHF waves are comparable to the size of buildings, trees, vehicles and other common objects, reflection anddiffractionfrom these objects can causefadingdue tomultipath propagation,especially in built-up urban areas. Atmospheric moisture reduces, orattenuates,the strength of UHF signals over long distances, and the attenuation increases with frequency. UHF TV signals are generally more degraded by moisture than lower bands, such asVHFTV signals.

As the visual horizon sets the maximum range of UHF transmission to between 30 and 40 miles (48 to 64 km) or less, depending on local terrain, the same frequency channels can be reused by other users in neighboring geographic areas (frequency reuse). Radiorepeatersare used to retransmit UHF signals when a distance greater than the line of sight is required.

Occasionally when conditions are right, UHF radio waves can travel long distances bytropospheric ductingas the atmosphere warms and cools throughout the day.

Antennas[edit]

See also:UHF television broadcasting § UHF vs VHF
RetevisGMRStwo-way radiosoperating on 462 and 467 MHz in the UHF band, showing the short antennas used
Corner reflector UHF-TV antenna from 1950s

The length of anantennais related to the length of the radio waves used. Due to the short wavelengths, UHF antennas are conveniently stubby and short; at UHF frequencies aquarter-wave monopole,the most commonomnidirectional antennais between 2.5 and 25 cm long. UHF wavelengths are short enough that efficient transmitting antennas are small enough to mount on handheld and mobile devices, so these frequencies are used for two-wayland mobile radio systems,such aswalkie-talkies,two-way radiosin vehicles, and for portablewireless devices;cordless phonesandcell phones.Omnidirectional UHF antennas used on mobile devices are usually shortwhips,sleevedipoles,rubber ducky antennasor the planarinverted F antenna(PIFA) used in cellphones. Higher gain omnidirectional UHF antennas can be made ofcollinear arraysof dipoles and are used for mobile base stations andcellular base station antennas.

The short wavelengths also allowhigh gain antennasto be conveniently small. High gain antennas forpoint-to-pointcommunication links and UHF television reception are usuallyYagi,log periodic,corner reflectors,orreflective array antennas.At the top end of the band,slot antennasandparabolic dishesbecome practical. For satellite communication,helicalandturnstile antennasare used since satellites typically employcircular polarizationwhich is not sensitive to the relative orientation of the transmitting and receiving antennas. For television broadcasting specialized vertical radiators that are mostly modifications of the slot antenna or reflective array antenna are used: the slotted cylinder, zig-zag, and panel antennas.

Applications[edit]

UHF television broadcastingfulfilled the demand for additional over-the-air television channels in urban areas. Today, much of the bandwidth has been reallocated toland mobile radio system,trunked radioandmobile telephoneuse. UHF channels are still used fordigital television.

Since at UHF frequencies transmitting antennas are small enough to install on portable devices, the UHF spectrum is used worldwide for land mobile radio systems,two-way radiosused for voice communication for commercial, industrial, public safety, and military purposes. Examples ofpersonal radio servicesareGMRS,PMR446,andUHF CB.Some wireless computer networks use UHF frequencies. The widely adoptedGSMandUMTScellular networks use UHFcellular frequencies.

Major telecommunications providers have deployed voice and data cellular networks in VHF/UHF range. This allowsmobile phonesandmobile computingdevices to be connected to thepublic switched telephone networkand theInternet.Satellite phones also use this frequency in theL bandandS band.

UHF radars are said to be effective at tracking stealth fighters, if not stealth bombers.[3]

Wi-Fi operates between 2,412 and 2,484 MHz. LTE also operates on UHF frequencies.

Examples of UHF frequency allocations[edit]

Australia[edit]

  • 406–406.1 MHz: Mobile satellite service[4]
  • 450.4875–451.5125 MHz:Fixed point-to-point link
  • 457.50625–459.9875 MHz: Land mobile service
  • 476–477 MHz:UHF citizens band(Land mobile service)
  • 503–694 MHz:UHF channelsfor television broadcasting

Canada[edit]

  • 430–450 MHz: Amateur radio (70 cm band)
  • 470–806 MHz:Terrestrial television(with select channels in the 600 & 700 MHz bands left vacant)
  • 1452–1492 MHz:Digital Audio Broadcasting(L band)[5]
  • Many other frequency assignments for Canada and Mexico are similar to their US counterparts

France[edit]

New Zealand[edit]

United Kingdom[edit]

  • 380–399.9 MHz:Terrestrial Trunked Radio(TETRA) service for emergency use
  • 430–440 MHz: Amateur radio (70 cm band)
  • 446.0–446.2 MHz: European unlicensed PMR service =>PMR446
  • 457–464 MHz: Scanning telemetry and telecontrol, assigned mostly to the water, gas, and electricity industries
  • 606–614 MHz: Radio microphones and radio-astronomy
  • 470–862 MHz: Previously used foranalogue TV channels 21–69(until 2012).
    • Currently channels 21 to 37 and 39 to 48 are used forFreeviewdigital TV.[6]Channels 55 to 56 were previously used by temporary muxes COM7 and COM8, channel 38 was used for radio astronomy but has been cleared to allowPMSEusers access on a licensed, shared basis.
    • 694–790 MHz:[7]i.e. Channels 49 to 60 have been cleared, to allow these channels to be allocated for 5G cellular communication.
    • 791–862 MHz,[8]i.e. channels 61 to 69 inclusive were previously used for licensed and shared wireless microphones (channel 69 only), has since been allocated to 4G cellular communications.
  • 863–865 MHz: Used for licence-exempt wireless systems.
  • 863–870 MHz:Short range devices,LPWANIoTdevices such asNarrowBand-IoT.
  • 870–960 MHz: Cellular communications (GSM900 - Vodafone and O2 only) including GSM-R and future TETRA
  • 1240–1325 MHz: Amateur radio (23 cm band)
  • 1710–1880 MHz: 2G Cellular communications (GSM1800)
  • 1880–1900 MHz:DECTcordless telephone
  • 1900–1980 MHz: 3G cellular communications (mobile phone uplink)
  • 2110–2170 MHz: 3G cellular communications (base station downlink)
  • 2310–2450 MHz: Amateur radio (13 cm band)

United States[edit]

UHF channels are used fordigital television broadcastingon bothover the air channelsandcable television channels.Since 1962, UHF channel tuners (at the time, channels 14 to 83) have been required in television receivers by theAll-Channel Receiver Act.However, because of their more limited range, and because few sets could receive them until older sets were replaced, UHF channels were less desirable to broadcasters thanVHFchannels (and licenses sold for lower prices).

A complete list of US Television Frequency allocations can be found atPan-American television frequencies.

There is a considerable amount of lawful unlicensed activity (cordless phones, wireless networking) clustered around 900 MHz and 2.4 GHz, regulated underTitle 47 CFR Part 15.TheseISM bands—frequencies with a higher unlicensed power permitted for use originally by Industrial, Scientific, Medical apparatus—are now some of the most crowded in the spectrum because they are open to everyone. The 2.45 GHz frequency is the standard for use bymicrowave ovens,adjacent to the frequencies allocated forBluetoothnetwork devices.

The spectrum from 806 MHz to 890 MHz (UHF channels 70 to 83) was taken away from TV broadcast services in 1983, primarily foranalog mobile telephony.

In 2009, as part of thetransition from analog to digital over-the-air broadcast of television,the spectrum from 698 MHz to 806 MHz (UHF channels 52 to 69) was removed from TV broadcasting, making it available for other uses. Channel 55, for instance, was sold toQualcommfor theirMediaFLOservice, which was later sold to AT&T, and discontinued in 2011. Some US broadcasters had been offered incentives to vacate this channel early, permitting its immediate mobile use. TheFCC's scheduledauction for this newly available spectrumwas completed in March 2008.[9]

  • 225–420 MHz: Government use, includingmeteorology,military aviation, and federal two-way use[10]
  • 420–450 MHz: Government radiolocation,amateur radio satelliteandamateur radio(70 cm band),MedRadio[11]
  • 450–470 MHz: UHF business band,General Mobile Radio Service,andFamily Radio Service2-way "walkie-talkies", public safety
  • 470–512 MHz: Low-band TV channels 14 to 20 (shared with public safetyland mobile2-way radio in 12 major metropolitan areas scheduled to relocate to 700 MHz band by 2023[12])
  • 512–608 MHz: Medium-band TV channels 21 to 36
  • 608–614 MHz:Channel 37used forradio astronomyand wireless medical telemetry[13]
  • 614–698 MHz: Mobile broadband shared with TV channels 38 to 51auctioned in April 2017.TV stations were relocated by 2020.
    • 617–652 MHz: Mobile broadband service downlink
    • 652–663 MHz: Wireless microphones (higher priority) and unlicensed devices (lower priority)
    • 663–698 MHz: Mobile broadband service uplink
  • 698–806 MHz:Was auctioned in March 2008;bidders got full use after the transition todigital TVwas completed on June 12, 2009 (formerly high-band UHF TV channels 52 to 69) and recently modified in 2021 for Next Generation 5G UHF transmission bandwidth for 'over the air' channels 2 thru 69 (virtual 1 thru 36).
  • 806–816 MHz: Public safety and commercial 2-way (formerly TV channels 70 to 72)
  • 817–824 MHz: ESMR band for wideband mobile services (mobile phone) (formerly public safety and commercial 2-way)
  • 824–849 MHz: Cellular A & B franchises, terminal (mobile phone) (formerly TV channels 73 to 77)
  • 849–851 MHz: Commercial aviation air-ground systems (Gogo)
  • 851–861 MHz: Public safety and commercial 2-way (formerly TV channels 77 to 80)
  • 862–869 MHz: ESMR band for wideband mobile services (base station) (formerly public safety and commercial 2-way)
  • 869–894 MHz: Cellular A & B franchises, base station (formerly TV channels 80 to 83)
  • 894–896 MHz: Commercial aviation air-ground systems (Gogo)
  • 896–901 MHz: Commercial 2-way radio
  • 901–902 MHz: Narrowband PCS: commercial narrowband mobile services
  • 902–928 MHz:ISM band,amateur radio (33 cm band), cordless phones and stereo,radio-frequency identification,datalinks
  • 928–929 MHz:SCADA,alarm monitoring, meter reading systems and other narrowband services for a company's internal use
  • 929–930 MHz: Pagers
  • 930–931 MHz: Narrowband PCS: commercial narrowband mobile services
  • 931–932 MHz: Pagers
  • 932–935 MHz: Fixed microwave services: distribution of video, audio and other data
  • 935–940 MHz: Commercial 2-way radio
  • 940–941 MHz: Narrowband PCS: commercial narrowband mobile services
  • 941–960 MHz: Mixed studio-transmitter fixed links,SCADA,other.
  • 960–1215 MHz: Aeronautical radionavigation
  • 1240–1300 MHz: Amateur radio (23 cm band)
  • 1300–1350 MHz: Long range radar systems
  • 1350–1390 MHz: Military air traffic control and mobile telemetry systems at test ranges
  • 1390–1395 MHz: Proposed wireless medical telemetry service.TerreStarfailed to provide service by the required deadline.[14]
  • 1395–1400 MHz: Wireless medical telemetry service
  • 1400–1427 MHz: Earth exploration, radio astronomy, and space research
  • 1427–1432 MHz: Wireless medical telemetry service
  • 1432–1435 MHz: Proposed wireless medical telemetry service.TerreStarfailed to provide service by the required deadline.[14]
  • 1435–1525 MHz: Military use mostly for aeronautical mobile telemetry (therefore not available forDigital Audio Broadcasting,unlike Canada/Europe)
  • 1525–1559 MHz:Skyterradownlink (Ligadois seeking FCC permission for terrestrial use[15])
    • 1526–1536 MHz: proposed Ligado downlink
    • 1536–1559 MHz: proposed guard band
  • 1559–1610 MHz:Radio Navigation Satellite Services(RNSS) Upper L-band
    • 1563–1587 MHz:GPSL1 band
    • 1593–1610 MHz:GLONASSG1 band
    • 1559–1591 MHz:GalileoE1 band (overlapping with GPS L1[16])
  • 1610–1660.5 MHz: Mobile Satellite Service
    • 1610–1618:Globalstaruplink
    • 1618–1626.5 MHz:Iridiumuplink and downlink[15]
    • 1626.5–1660.5 MHz:Skyterrauplink (Ligadois seeking FCC permission for terrestrial use[15])
      • 1627.5–1637.5 MHz: proposed Ligado uplink 1
      • 1646.5–1656.5 MHz: proposed Ligado uplink 2
  • 1660.5–1668.4 MHz: Radio astronomy observations. Transmitting is not permitted.
  • 1668.4–1670 MHz: Radio astronomy observations. Weather balloons may utilize the spectrum after an advance notice.
  • 1670–1675 MHz:Geostationary Operational Environmental Satellitetransmissions to threeearth stationsin Wallops Island, Virginia; Greenbelt, Maryland and Fairbanks, Alaska. Nationwide broadband service license in this range is held by a subsidiary ofCrown Castle International Corp.who is trying to provide service in cooperation withLigado Networks.[17]
  • 1675–1695 MHz: Meteorological federal users
  • 1695–1780 MHz:AWSmobile phone uplink (UL) operating band
    • 1695–1755 MHz: AWS-3 blocks A1 and B1
    • 1710–1755 MHz: AWS-1 blocks A, B, C, D, E, F
    • 1755–1780 MHz: AWS-3 blocks G, H, I, J (various federal agencies transitioning by 2025[18])
  • 1780–1850 MHz: exclusive federal use (Air Force satellite communications, Army's cellular-like communication system, other agencies)
  • 1850–1920 MHz: PCS mobile phone—order is A, D, B, E, F, C, G, H blocks. A, B, C = 15 MHz; D, E, F, G, H = 5 MHz
  • 1920–1930 MHz:DECTcordless telephone
  • 1930–2000 MHz: PCS base stations—order is A, D, B, E, F, C, G, H blocks. A, B, C = 15 MHz; D, E, F, G, H = 5 MHz
  • 2000–2020 MHz: lower AWS-4 downlink (mobile broadband)
  • 2020–2110 MHz: Cable Antenna Relay service, Local Television Transmission service, TV Broadcast Auxiliary service, Earth Exploration Satellite service
  • 2110–2200 MHz:AWSmobile broadband downlink
    • 2110–2155 MHz: AWS-1 blocks A, B, C, D, E, F
    • 2155–2180 MHz: AWS-3 blocks G, H, I, J
    • 2180–2200 MHz: upper AWS-4
  • 2200–2290 MHz:NASAsatellite tracking, telemetry and control (space-to-Earth, space-to-space)
  • 2290–2300 MHz:NASA Deep Space Network
  • 2300–2305 MHz: Amateur radio (13 cm band,lower segment)
  • 2305–2315 MHz: WCS mobile broadband service uplink blocks A and B
  • 2315–2320 MHz: WCS block C (AT&T is pursuingsmart griddeployment[19])
  • 2320–2345 MHz:Satellite radio(Sirius XM)
  • 2345–2350 MHz: WCS block D (AT&T is pursuingsmart griddeployment[19])
  • 2350–2360 MHz: WCS mobile broadband service downlink blocks A and B
  • 2360–2390 MHz: Aircraft landing and safety systems
  • 2390–2395 MHz: Aircraft landing and safety systems (secondary deployment in a dozen of airports), amateur radio otherwise
  • 2395–2400 MHz: Amateur radio (13 cm band,upper segment)
  • 2400–2483.5 MHz:ISM,IEEE 802.11,802.11b, 802.11g, 802.11n wirelessLAN,IEEE 802.15.4-2006,Bluetooth,radio-controlled aircraft(strictly forspread spectrumuse),microwave ovens,Zigbee
  • 2483.5–2495 MHz:Globalstardownlink and Terrestrial Low Power Service suitable for TD-LTE small cells[20]
  • 2495–2690 MHz: Educational Broadcast and Broadband Radio Services[21]
  • 2690–2700 MHz: Receive-only range for radio astronomy and space research

See also[edit]

References[edit]

  1. ^"IEEE 521-2002 - IEEE Standard Letter Designations for Radar-Frequency Bands".Standards.ieee.org.Retrieved17 December2017.
  2. ^Seybold, John S. (2005).Introduction to RF Propagation.John Wiley and Sons. pp. 55–58.ISBN0471743682.
  3. ^MINNICK, WENDELL (22 November 2014)."China's Anti-Stealth Radar Comes to Fruition".Defensenews.Gannett.Retrieved25 November2014.
  4. ^"400 MHz Plan"(PDF).acma.gov.Archived fromthe original(PDF)on April 4, 2019.RetrievedNovember 3,2019.
  5. ^"Digital Audio Broadcasting (DAB) - History of Canadian Broadcasting".Broadcasting-history.ca.Retrieved15 October2017.
  6. ^"What is 700MHz Clearance?".Freeview.
  7. ^"Decision to make the 700 MHz band available for mobile data - statement"(PDF).Retrieved4 April2020.
  8. ^"800 MHz & 2.6 GHz Combined Award".The Office of Communications. May 9, 2012.Retrieved2014-11-21.
  9. ^Hansell, Saul (March 18, 2008)."Going Once…Going Twice…The 700 Mhz Spectrum is Sold".Bits.blos.nytimes.Retrieved15 October2017.
  10. ^[1][dead link]
  11. ^"Federal Government Spectrum Use Reports 225 MHz – 7.125 GHz".NTIA.Dec 2015 – Aug 2017.RetrievedOctober 21,2019.
  12. ^"T-Band Report"(PDF).Npstc.org.March 15, 2013.Retrieved17 December2017.
  13. ^"Wireless Medical Telemetry Service (WMTS)".Federal Communications Commission.3 November 2011.Retrieved17 December2017.
  14. ^ab"TerreStar Corporation Request for Temporary Waiver of Substantial Service Requirements for 1.4 GHz Licenses"(PDF).the FCC.2017-10-10.Retrieved2017-10-11.
  15. ^abc"Ligado Ex Parte re Iridium Analysis (PUBLIC 11-2-2016)"(PDF).Ecfsapi.fcc.gov.Retrieved17 December2017.
  16. ^"Galileo Signal Plan".Navipedia.net.Retrieved17 December2017.
  17. ^"Request for waiver and public interest statement".FCC.2016-06-04.Retrieved2018-04-02.
  18. ^"AWS-3 Transition".Ntia.doc.gov.January 29, 2015.Retrieved17 December2017.
  19. ^ab"AT&T Mobility Petition for Limited Waiver of Interim Performance Requirement for 2.3 GHz WCS C and D Block Licenses"(PDF).Ecfsapi.fcc.gov.Retrieved17 December2017.
  20. ^"Globalstar Overview"(PDF).Globalstar.2017.Archived(PDF)from the original on August 2, 2017.Retrieved17 December2017.
  21. ^"Broadband Radio Service & Education Broadband Service".The FCC.February 2016.Retrieved2018-06-05.

External links[edit]

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