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VERY HIGH FREQUENCY (VHF) is the ITU designation for the range of radio frequency electromagnetic waves (radio waves ) from 30 to 300 Megahertz (MHz), with corresponding wavelengths of ten to one meters. Frequencies immediately below VHF are denoted high frequency (HF), and the next higher frequencies are known as ultra high frequency (UHF).

Common uses for VHF are FM radio broadcasting, television broadcasting, two way land mobile radio systems (emergency, business, private use and military), long range data communication up to several tens of kilometres with radio modems , amateur radio , and marine communications . Air traffic control communications and air navigation systems (e.g. VOR "> "Rabbit-ears" VHF television antenna (the small loop is a separate UHF
UHF
antenna).

For analog TV, VHF transmission range is a function of transmitter power, receiver sensitivity, and distance to the horizon, since VHF signals propagate under normal conditions as a near line-of-sight phenomenon. The distance to the radio horizon is slightly extended over the geometric line of sight to the horizon, as radio waves are weakly bent back toward the Earth by the atmosphere.

An approximation to calculate the line-of-sight horizon distance (on Earth) is:

* distance in nautical miles = 1.23 A f {displaystyle 1.23times {sqrt {A_{f}}}} where A f {displaystyle A_{f}} is the height of the antenna in feet * distance in kilometres = 12.746 A m {displaystyle {sqrt {12.746times A_{m}}}} where A m {displaystyle A_{m}} is the height of the antenna in metres.

These approximations are only valid for antennas at heights that are small compared to the radius of the Earth. They may not necessarily be accurate in mountainous areas, since the landscape may not be transparent enough for radio waves.

In engineered communications systems, more complex calculations are required to assess the probable coverage area of a proposed transmitter station.

The accuracy of these calculations for digital TV signals is being debated.

ANTENNAS

A VHF television broadcasting antenna. This is a common type called a super turnstile or batwing antenna .

VHF is the first band at which wavelengths are small enough that efficient transmitting antennas are short enough to mount on vehicles and handheld devices, so the VHF and UHF
UHF
wavelengths are used for two way radios in vehicles, aircraft, and handheld transceivers and walkie talkies . Portable radios usually use whips or rubber ducky antennas , while base stations usually use larger fiberglass whips or collinear arrays of vertical dipoles.

For directional antennas, the Yagi antenna is the most widely used as a high gain or "beam" antenna. For television reception, the Yagi is used, as well as the log periodic antenna due to its wider bandwidth. Helical and turnstile antennas are used for satellite communication since they employ circular polarization . For even higher gain, multiple Yagis or helicals can be mounted together to make array antennas . Vertical collinear arrays of dipoles can be used to make high gain omnidirectional antennas , in which more of the antenna's power is radiated in horizontal directions. Television
Television
and FM broadcasting stations use collinear arrays of specialized dipole antennas such as batwing antennas .

UNIVERSAL USE

Certain subparts of the VHF band have the same use around the world. Some national uses are detailed below.

* 50–54 MHz: Amateur Radio 6-meter band. * 108–118 MHz: Air navigation beacons VOR and Instrument Landing System localiser. * 118–137 MHz: Airband for air traffic control , AM , 121.5 MHz is emergency frequency * 144–148 MHz: Amateur Radio 2-meter band.

BY COUNTRY

A plan showing VHF use in television , FM radio , amateur radio , marine radio and aviation .

AUSTRALIA

See also: Australasian television frequencies

The VHF T V band in Australia was originally allocated channels 1 to 10—with channels 2, 7 and 9 assigned for the initial services in Sydney and Melbourne, and later the same channels were assigned in Brisbane, Adelaide and Perth. Other capital cities and regional areas used a combination of these and other frequencies as available. The initial commercial services in Hobart and Darwin were respectively allocated channels 6 and 8 rather than 7 or 9.

By the early 1960s it became apparent that the 10 VHF channels were insufficient to support the growth of television services. This was rectified by the addition of three additional frequencies—channels 0, 5A and 11. Older television sets using rotary dial tuners required adjustment to receive these new channels. Most TVs of that era were not equipped to receive these broadcasts, and so were modified at the owners' expense to be able to tune into these bands; otherwise the owner had to buy a new TV.

Several TV stations were allocated to VHF channels 3, 4 and 5, which were within the FM radio bands although not yet used for that purpose. A couple of notable examples were NBN-3 Newcastle , WIN-4 Wollongong and ABC Newcastle on channel 5. While some Channel 5 stations were moved to 5A in the 1970s and 80s, beginning in the 1990s, the Australian Broadcasting Authority began a process to move these stations to UHF
UHF
bands to free up valuable VHF spectrum for its original purpose of FM radio. In addition, by 1985 the federal government decided new TV stations are to be broadcast on the UHF band.

Two new VHF, 9A and 12, have since been made available and are being used primarily for digital services (e.g. ABC in capital cities) but also for some new analogue services in regional areas. Because channel 9A is not used for television services in or near Sydney, Melbourne, Brisbane, Adelaide or Perth, digital radio in those cities are broadcast on DAB frequencies blocks 9A, 9B and 9C.

NEW ZEALAND

* 44–51, 54–68 MHz: Band I Television
Television
(channels 1–3) * 87.5–108 MHz: Band II Radio * 174–230 MHz: Band III Television
Television
(channels 4–11)

In New Zealand
New Zealand
, the four main Free-to-Air TV stations still use the VHF Television
Television
bands ( Band I and Band III ) to transmit to New Zealand households. Other stations, including a variety of pay and regional free-to-air stations, are forced to broadcast in the UHF
UHF
band, since the VHF band is very overloaded with four stations sharing a very small frequency band, which can be so overcrowded that one or more channels, more often than not one of the MediaWorks-owned channels (Three , Bravo , and The Edge TV ), is unavailable in some smaller towns.

However, at the end of 2013, all television channels stopped broadcasting on the VHF bands.

Refer to Australasian television frequencies for more information.

UNITED KINGDOM

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British television originally used VHF band I and band III . Television
Television
on VHF was in black and white with 405-line format (although there were experiments with all three colour systems—NTSC , PAL
PAL
, and SECAM —adapted for the 405-line system in the late 1950s and early 60s).

British colour television was broadcast on UHF
UHF
(channels 21–69), beginning in the late 1960s. From then on, TV was broadcast on both VHF and UHF
UHF
(VHF being a monochromatic downconversion from the 625-line colour signal), with the exception of BBC2 (which had always broadcast solely on UHF). The last British VHF TV transmitters closed down on January 3, 1985. VHF band III is now used in the UK for digital audio broadcasting , and VHF band II is used for FM radio , as it is in most of the world.

Unusually, the UK has an amateur radio allocation at 4 metres , 70–70.5 MHz.

UNITED STATES AND CANADA

Frequency
Frequency
assignments between US and Canadian users are closely coordinated since much of the Canadian population is within VHF radio range of the US border. Certain discrete frequencies are reserved for radio astronomy . The general services in the VHF band are:

* 30–49.6 MHz: Licensed 2-way land mobile communication. Various sub-bands * 30–88 MHz: Military VHF-FM , including SINCGARS * 43–50 MHz: Cordless telephones , 49 MHz FM walkie-talkies and radio controlled toys, and mixed 2-way mobile communication. The FM broadcast band originally operated here (42–50 MHz) before moving to 88–108 MHz. * 50–54 MHz: Amateur radio 6-meter band * 54–72 and 76–88 MHz TV channels 2 through 6 (VHF-Lo), known as "Band I" internationally; some DTV stations will appear here. See North American broadcast television frequencies * 72–76 MHz: Radio
Radio
controlled models, industrial remote control, and other devices. Model aircraft operate on 72 MHz while surface models operate on 75 MHz in the USA and Canada, air navigation beacons 74.8–75.2 MHz. * 87.5–108 MHz: FM radio broadcasting (87.9–91.9 non-commercial, 92–108 commercial in the United States) (known as "Band II" internationally) * 108–118 MHz: Air navigation beacons VOR * 118–137 MHz: Airband for air traffic control , AM , 121.5 MHz is an emergency frequency * 137–138 Space research, space operations, meteorological satellite * 138–144 MHz: Land mobile, auxiliary civil services, satellite, space research, and other miscellaneous services * 144–148 MHz: Amateur radio 2-meter band
2-meter band
* 148–150 MHz: Land mobile, fixed, satellite * 150–156 MHz: "VHF business band ," public safety, the unlicensed Multi-Use Radio Service (MURS), and other 2-way land mobile, FM * 156–158 MHz VHF Marine Radio
Radio
; 156.8 MHz (Channel 16) is the maritime emergency and contact frequency. * 159.81–161.565 MHz railways 159.81–160.2 are railroads in Canada only and is used by trucking companies in the U.S. * 160.6–162 Wireless microphones and TV/FM broadcast remote pickup * 162.40–162.55: NOAA Weather Stations , narrowband FM, Weatheradio Canada Stations * 174–216 MHz television channels 7–13 (VHF-Hi), known as "Band III" internationally. A number of DTV channels have begun broadcasting here, especially many of the stations which were assigned to these channels for previous analog operation. * 174–216 MHz: professional wireless microphones (low power, certain exact frequencies only) * 216–222 MHz: land mobile, fixed, maritime mobile, * 222–225 MHz: 1.25 meters (US) (Canada 219–220, 222–225 MHz) amateur radio * 225 MHz and above(UHF): Military aircraft radio, 243 MHz is an emergency frequency (225–400 MHz) AM, including HAVE QUICK , dGPS RTCM-104

Cable television
Cable television
, though not transmitted aerially, uses a spectrum of frequencies overlapping VHF.

VHF Television

The U.S. FCC allocated television broadcasting to a channelized roster as early as 1938 with 19 channels. That changed 3 more times: in 1940 when Channel 19 was deleted and several channels changed frequencies, then in 1946 with television going from 18 to 13 channels with different frequencies again, and finally in 1948 with the removal of Channel 1 (channels 2–13 remain as they are today).

The move from VHF for analog television to UHF
UHF
for digital television has made the large technically and commercially valuable slice of the VHF spectrum formerly taken up by television broadcasting available for relicensing or sale after a transition period, which ended June 12, 2009 in the United States
United States
; see Effect on existing analog technology for dates in other countries.

87.5–87.9 MHz

87.5–87.9 MHz is a radio frequency which, in most of the world, is used for FM broadcasting . In North America
North America
, however, this bandwidth is allocated to VHF television channel 6 (82–88 MHz). The analog audio for TV channel 6 is broadcast at 87.75 MHz (adjustable down to 87.74). Several stations, most notably those joining the Pulse 87 franchise, have operated on this frequency as radio stations, though they use television licenses. As a result, FM radio receivers such as those found in automobiles which are designed to tune into this frequency range could receive the audio for analog-mode programming on the local TV channel 6 while in North America.

87.9 MHz is normally off-limits for FM audio broadcasting except for displaced class D stations which have no other frequencies in the normal 88.1–107.9 MHz subband on which to move. So far, only 2 stations have qualified to operate on 87.9 MHz: 10-watt KSFH in Mountain View, California and 34-watt translator K200AA in Sun Valley, Nevada .

UNLICENSED OPERATION

In some countries, particularly the United States
United States
and Canada, limited low-power license-free operation is available in the FM broadcast band for purposes such as micro-broadcasting and sending output from CD or digital media players to radios without auxiliary-in jacks, though this is illegal in some other countries. This practice was legalised in the United Kingdom on 8 December 2006.

SEE ALSO

* Marine VHF radio * List of oldest radio stations * Apex (radio band) * FM broadcast band * Moving image formats * Polar mesosphere summer echoes * Television
Television
channel frequencies * Knife-edge effect * Instrument Landing System * VHF omnidirectional range

REFERENCES

* ^ "Rec. ITU-R V.431-7, Nomenclature of the frequency and wavelength bands used in telecommunications" (PDF). ITU. Retrieved 20 February 2013. * ^ Seybold, John S. (2005). Introduction to RF Propagation. John Wiley and Sons. pp. 55–58. ISBN 0471743682 . * ^ Grotticelli, Michael (2009-06-22). "DTV Transition Not So Smooth in Some Markets". Broadcast Engineering. Archived from the original on June 28, 2009. Retrieved 2009-06-24. * ^ "Going Digital - When is my area going digital?". goingdigital.co.nz. Ministry for Culture and Heritage. Retrieved 20 October 2011. * ^ The 42 MHz Segment is still currently used by the California Highway Patrol , New Jersey State Police , Tennessee Highway Patrol and other state law enforcement agencies. * ^ Industry Canada, Canadian Table of Frequency
Frequency
Allocations 9 kHz - 275 GHz, 2005 Edition (revised February 2007) pg. 29 * ^ The 160 and 161 areas are AAR 99 channel railroad radios issued to the railroad (Sample, AAR 21 is 160.425 and that is issued to TVRM and other railroads that want AAR 21). * ^ Canadian table pg. 30 * ^ http://www.jneuhaus.com/fccindex/cablech.html * ^ Tech Notes: What Ever Happened to Channel 1?-Table 1. Retrieved March 27, 2014. * ^ "Ofcom Change to the law to allow the use of low power FM transmitters for MP3 players". Media.ofcom.org.uk. Retrieved 2012-10-02.

* v * t * e

BROADCAST BANDS WITH ROMAN NUMERAL DESIGNATIONS

VHF

* Band I * Band II * Band III

UHF
UHF

* Band IV * Band V

SHF

* Band VI

* v * t * e

Radio spectrum (ITU)

ELF 3 Hz/100 Mm 30 Hz/10 Mm

SLF 30 Hz/10 Mm 300 Hz/1 Mm

ULF 300 Hz/1 Mm 3 kHz/100 km

VLF 3 kHz/100 km 30 kHz/10 km

LF 30 kHz/10 km 300 kHz/1 km

MF 300 kHz/1 km 3 MHz/100 m

HF 3 MHz/100 m 30 MHz/10 m

VHF 30 MHz/10 m 300 MHz/1 m

UHF
UHF
300 MHz/1 m 3 GHz/100 mm

SHF 3 GHz/100 mm 30 GHz/10 mm

EHF 30 GHz/10 mm 300 GHz/1 mm

THF 300 GHz/1 mm 3 THz/0.1 mm

* v * t * e

Electromagnetic spectrum

← higher frequencies longer wavelengths →

* Gamma rays * X-rays * Ultraviolet
Ultraviolet
* Visible * Infrared
Infrared
* Terahertz radiation * Microwave * Radio
Radio

VISIBLE (OPTICAL)

* Violet * Blue
Blue
* Green
Green
* Yellow
Yellow
* Orange * Red
Red

MICROWAVES

* W band * V band * Q band * Ka band * K band * Ku band * X band * S band * C band * L band

RADIO

* EHF * SHF * UHF
UHF
* VHF * HF * MF * LF * VLF * ULF * SLF * ELF

WAVELENGTH TYPES

* Microwave * Shortwave * Medium wave * Longwave

* v * t * e

Telecommunications

HISTORY

* Beacon * Broadcasting * Cable protection system * Cable TV * Communications satellite * Computer network * Drums * Electrical telegraph * Fax * Heliographs * Hydraulic telegraph * Internet
Internet
* Mass media * Mobile phone * Optical telecommunication * Optical telegraphy * Pager * Photophone * Prepaid mobile phone * Radio
Radio
* Radiotelephone * Satellite communications * Semaphore
Semaphore
* Smartphone
Smartphone
* Smoke signals * Telecommunications history * Telautograph * Telegraphy
Telegraphy
* Teleprinter (teletype) * Telephone * The Telephone Cases * Television
Television
* Timeline of communication technology * Undersea telegraph line * Videoconferencing * Videophone * Videotelephony * Whistled language

PIONEERS

* Edwin Howard Armstrong * John Logie Baird
John Logie Baird
* Paul Baran * Alexander Graham Bell
Alexander Graham Bell
* Tim Berners-Lee * Jagadish Chandra Bose * Vint Cerf
Vint Cerf
* Claude Chappe * Donald Davies * Lee de Forest * Philo Farnsworth * Reginald Fessenden * Elisha Gray * Erna Schneider Hoover * Charles K. Kao * Hedy Lamarr * Innocenzo Manzetti * Guglielmo Marconi
Guglielmo Marconi
* Antonio Meucci * Radia Perlman * Alexander Stepanovich Popov
Alexander Stepanovich Popov
* Johann Philipp Reis * Nikola Tesla * Camille Tissot * Alfred Vail * Charles Wheatstone
Charles Wheatstone
* Vladimir K. Zworykin

Transmission media

* Characteristic impedance * Coaxial cable
Coaxial cable
* Electromagnetic radiation * Electrical cable * Free-space optical communication * Heaviside condition * Loading coil * Molecular communication * Optical fiber * Telegrapher\'s equations

Network topology and switching

* Links * Nodes * Terminal node * Network switching (circuit * packet ) * Telephone exchange

MULTIPLEXING

* Space-division * Frequency-division * Time-division * Polarization-division * Orbital angular-momentum * Code-division

NETWORKS

* ARPANET * BITNET * Cellular network * Computer * CYCLADES * Ethernet
Ethernet
* FidoNet * Internet
Internet
* ISDN * LAN * Mobile * NGN * NPL network * Public Switched Telephone * Radio
Radio
* Telecommunications equipment * Television
Television
* Telex
Telex
* WAN * Wireless * World Wide Web
World Wide Web

* Category * Portal
Portal

* v * t * e

Analog television broadcasting topics

SYSTEMS

* 180-line * 405-line ( System A ) * 441-line * 525-line ( System J , System M ) * 625-line ( System B , System C , System D , System G , System H , System I , System K , System L , System N ) * 819-line ( System E , System F )

COLOR SYSTEMS

* NTSC
NTSC
* PAL
PAL
* PAL-M * PAL-S * PALplus * SECAM

VIDEO

* Back porch and front porch * Black level * Blanking level * Chrominance * Chrominance subcarrier * Colorburst * Color killer * Color TV * Composite video
Composite video
* Frame (video) * Horizontal scan rate * Horizontal blanking interval * Luma * Nominal analogue blanking * Overscan * Raster scan * Safe area * Television
Television
lines * Vertical blanking interval * White clipper

SOUND

* Multichannel television sound * NICAM * Sound-in-Syncs * Zweikanalton

MODULATION

* Frequency modulation * Quadrature amplitude modulation * Vestigial sideband modulation (VSB)

TRANSMISSION

* Amplifiers * Antenna (radio) * Broadcast transmitter / Transmitter station * Cavity amplifier * Differential gain * Differential phase * Diplexer * Dipole antenna * Dummy load * Frequency
Frequency
mixer * Intercarrier method * Intermediate frequency * Output power of an analog TV transmitter * Pre-emphasis * Residual carrier * Split sound system * Superheterodyne transmitter * Television
Television
receive-only * Direct-broadcast satellite television * Television
Television
transmitter * Terrestrial television
Terrestrial television
* Transposer

FREQUENCIES border-left-width:2px;border-left-style:solid;width:100%;padding:0px">

* Frequency
Frequency
offset * Microwave transmission * Television
Television
channel frequencies * UHF
UHF
* VHF

PROPAGATION

* Beam tilt * Distortion * Earth bulge * Field strength in free space * Knife-edge effect * Noise (electronics) * Null fill * Path loss * Radiation pattern * Skew * Television
Television
interference

TESTING

* Distortionmeter * Field strength meter * Vectorscope
Vectorscope
* VIT signals * Zero reference pulse

ARTIFACTS

* Dot crawl * Ghosting * Hanover bars * Sparklies

* v * t * e

Analog and digital audio broadcasting

TERRESTRIAL

RADIO MODULATION

* AM * FM * COFDM

FREQUENCY ALLOCATIONS

* LW (LF ) * MW (MF ) * SW (HF ) * VHF (low / mid / high ) * L band ( UHF
UHF
)

DIGITAL SYSTEMS

* CAM-D * DAB/DAB+ * DRM/DRM+ *