very high frequency

TheInfoList

Very high frequency (VHF) is the
ITU 260px, ITU Monument, Bern The International Telecommunication Union is a specialized agency of the United Nations responsible for all matters related to information and communication technologies Information and communications technology ...

designation for the range of
radio frequency Radio frequency (RF) is the oscillation rate of an Alternating_current, alternating electric current or voltage or of a Magnetic_field, magnetic, electric or electromagnetic field or mechanical system in the frequency range from around to around ...
electromagnetic wave Electromagnetism is a branch of physics involving the study of the electromagnetic force, a type of physical interaction that occurs between electric charge, electrically charged particles. The electromagnetic force is carried by electromagneti ...

s (
radio wave Radio waves are a type of electromagnetic radiation In physics Physics (from grc, φυσική (ἐπιστήμη), physikḗ (epistḗmē), knowledge of nature, from ''phýsis'' 'nature'), , is the natural science that studies ma ...
s) from 30 to 300
megahertz The hertz (symbol: Hz) is the SI derived unit, derived unit of frequency in the International System of Units (SI) and is defined as one cycle (geometry), cycle per second. It is named after Heinrich Hertz, Heinrich Rudolf Hertz, the first per ...
(MHz), with corresponding wavelengths of ten meters to one meter. Frequencies immediately below VHF are denoted
high frequency High frequency (HF) is the ITU designation for the range of radio frequency Radio frequency (RF) is the oscillation rate of an Alternating_current, alternating electric current or voltage or of a Magnetic_field, magnetic, electric or electro ...
(HF), and the next higher frequencies are known as
ultra high frequency Ultra high frequency (UHF) is the ITU designation for radio frequencies in the range between 300  megahertz (MHz) and 3  gigahertz (GHz), also known as the decimetre band as the wavelengths range from one meter to one tenth of a meter ...

(UHF). VHF radio waves propagate mainly by line-of-sight, so they are blocked by hills and mountains, although due to refraction they can travel somewhat beyond the out to about 160 km (100 miles). Common uses for radio waves in the VHF band are
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 and promoted by the WorldDAB forum. The standard is dominant in Europe ...

(DAB) and
television broadcasting A television network or broadcaster is a telecommunications network for distribution of television program content, where a central operation provides programming to many television stations or pay television providers. Until the mid-1980s, te ...
, two-way land mobile radio systems (emergency, business, private use and military), long range data communication up to several tens of kilometers with
radio modem Radio modems are modems that transfer data wirelessly across a range of up to tens of kilometres. Using radio modems is a modern way to create Private Radio Networks (PRN). Private radio networks are used in critical industrial applications, when r ...
s,
amateur radio Amateur radio, also known as ham radio, is the use of radio frequency radio spectrum, spectrum for purposes of non-commercial exchange of messages, wireless experimentation, self-training, private recreation, radiosport, contesting, and emergen ...
, and marine communications.
Air traffic control Air traffic control (ATC) is a service provided by ground-based air traffic controllers who direct aircraft on the ground and through controlled airspace, and can provide advisory services to aircraft in non-controlled airspace. The primary purp ...
communications and air navigation systems (e.g. VOR & ILS) work at distances of or more to aircraft at cruising altitude. In the Americas and many other parts of the world, VHF
Band I Band I is a range of radio frequencies within the very high frequency Very high frequency (VHF) is the ITU designation for the range of radio frequency Radio frequency (RF) is the oscillation rate of an Alternating_current, alternating el ...
was used for the transmission of
analog television Analog or analogue may refer to: Computing and electronics * Analog signal An analog signal is any continuous signal for which the time-varying feature of the signal is a representation of some other time-varying quantity, i.e., ''analogous ...
. As part of the worldwide transition to digital terrestrial television most countries require broadcasters to air television in the VHF range using digital rather than analog format.

# Propagation characteristics

Radio waves in the VHF band propagate mainly by line-of-sight and ground-bounce paths; unlike in the HF band there is only some reflection at lower frequencies from the
ionosphere The ionosphere () is the ionized part of Earth's upper atmosphere, from about to altitude, a region that includes the thermosphere and parts of the mesosphere upright=0.5, Diagram showing the five primary layers of the Earth's atmosphere: exos ...
(
skywave off the ionosphere (red) during skywave propagation In radio communication, skywave or skip refers to the propagation of radio waves reflected or refracted back toward Earth from the ionosphere, an electrically charged layer of the upper a ...

propagation). They do not follow the contour of the Earth as
ground wave A diving thumb The thumb is the first digit of the hand A hand is a prehensile, multi- fingered appendage located at the end of the forearm The forearm is the region of the upper limb between the Elbow-joint, elbow and the wrist. The ter ...
s and so are blocked by hills and mountains, although because they are weakly refracted (bent) by the atmosphere they can travel somewhat beyond the out to about 160 km (100 miles). They can penetrate building walls and be received indoors, although in urban areas reflections from buildings cause
multipath propagation In radio communication, multipath is the propagation phenomenon that results in radio Radio is the technology of signaling and telecommunication, communicating using radio waves. Radio waves are electromagnetic waves of frequency between 30& ...
, which can interfere with television reception. Atmospheric
radio noise In radio Radio is the technology of signaling and telecommunication, communicating using radio waves. Radio waves are electromagnetic waves of frequency between 30 hertz (Hz) and 300 gigahertz (GHz). They are generated by an electroni ...
and interference ( RFI) from electrical equipment is less of a problem in this and higher frequency bands than at lower frequencies. The VHF band is the first band at which efficient transmitting antennas are small enough that they can be mounted on vehicles and portable devices, so the band is used for two-way land mobile radio systems, such as
walkie-talkie A walkie-talkie, more formally known as a handheld transceiver (HT), is a hand-held, portable, two-way radio transceiver. Its development during the Second World War has been variously credited to Donald Hings, radio engineer Alfred J. Gross, He ...
s, and
communication with aircraft (
Airband Airband or aircraft band is the name for a group of frequencies Frequency is the number of occurrences of a repeating event per unit of time. It is also referred to as temporal frequency, which emphasizes the contrast to spatial frequency an ...
) and ships (
marine radio Marine VHF radio is a worldwide system of two way radio transceivers on ships and watercraft used for bidirectional voice communication from ship-to-ship, ship-to-shore (for example with harbormasters), and in certain circumstances ship-to-ai ...
). Occasionally, when conditions are right, VHF waves can travel long distances by
tropospheric ducting Tropospheric propagation describes electromagnetic propagation in relation to the troposphere. The service area from a VHF or UHF radio transmitter extends to just beyond the horizon, optical horizon, at which point signals start to rapidly reduc ...
due to refraction by temperature gradients in the atmosphere.

# Line-of-sight calculation

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 Line-of-sight propagation is a characteristic of electromagnetic radiation or acoustic wave propagation which means waves travel in a direct path from the source to the receiver. Electromagnetic transmission includes light emissions travelin ...
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 = $1.23\times\sqrt$ where $A_f$ is the height of the antenna in feet *distance in kilometers = $\sqrt$ where $A_m$ is the height of the antenna in meters. 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 Digital television (DTV) is the transmission of television audiovisual signals using digital encoding, in contrast to the earlier analog television technology which used analog signals. At the time of its development it was considered an inn ...
signals is being debated.

# Antennas

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, a quarter wave whip antenna at VHF frequencies is 25 cm to 2.5 meter (10 inches to 8 feet) long. So the VHF and UHF wavelengths are used for
two-way radio station, a two-way radio used for recreational purposes by hobbyists called radio amateurs File:P25 hand-held radios.jpg, Several portable two-way radios designed for public services (police, fire, rescue) compatible with the Project 25 digital ...
s in vehicles, aircraft, and handheld
transceiver In Radio, radio communication, a transceiver is a device that is able to both transmit and receive information through a transmission medium. It is a combination of a transmitter, ''trans''mitter and a Radio receiver, re''ceiver'', hence the name ' ...

s and
walkie-talkie A walkie-talkie, more formally known as a handheld transceiver (HT), is a hand-held, portable, two-way radio transceiver. Its development during the Second World War has been variously credited to Donald Hings, radio engineer Alfred J. Gross, He ...
whips '' reins, featuring a quirt at the end of the ''romal'' A whip is a tool that was traditionally designed to strike animals or people to aid in guidance or exert control through pain compliance Pain compliance is the use of painful stimulus to c ...
or
rubber ducky antenna The rubber ducky antenna (or rubber duck aerial) is an electrically short monopole antenna monopole antenna of an AM radio station in Chapel Hill, North Carolina. The mast itself is connected to the transmitter and radiates the radio waves. ...
s, while base stations usually use larger fiberglass whips or collinear arrays of vertical dipoles. For directional antennas, the
Yagi antennaYagi may refer to: People YAGI Musician, Artist Places * Yagi, Kyoto, in Japan * Yagi (Kashihara), in Nara Prefecture, Japan *Yagi-nishiguchi Station, in Kashihara, Nara, Japan *Kami-Yagi Station, a JR-West Kabe Line station located in 3-chōme, Ya ...
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 A log-periodic antenna (LP), also known as a log-periodic array or log-periodic aerial, is a multi-element, directional antenna A directional antenna or beam antenna is an antenna which radiates or receives greater power in specific directions ...
due to its wider bandwidth.
Helical Helical may refer to: *Helix, the mathematical concept for the shape * Helical spring, a coilspring *Helical plc, a British property company, once a maker of steel bar stock * Helicoil, a mechanical thread repairing insert * H-el-ical//, stage name ...

and
turnstile antenna A turnstile antenna, or crossed-dipole antenna, is a radio antenna consisting of a set of two identical dipole antennas mounted at right angles to each other and fed in phase quadrature; the two currents applied to the dipoles are 90° out of ph ...
s are used for
satellite communication A communications satellite is an artificial satellite that relays and amplifies radio Radio is the technology of signaling and telecommunication, communicating using radio waves. Radio waves are electromagnetic waves of frequency between 30 ...
since they employ
circular polarization vectors of a traveling circularly polarized electromagnetic wave. This wave is right-circularly-polarized, since the direction of rotation of the vector is related by the right-hand rule to the direction the wave is moving; or left-circularly-pola ...
. 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 antenna on a walkie-talkie In radio communication, an omnidirectional antenna is a class of antenna which radiates equal radio power in all directions perpendicular to an axis (azimuth An azimuth (; from Arabic اَلسُّمُوت ''as-sumūt'' ...
s, in which more of the antenna's power is radiated in horizontal directions. 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 Amateur radio, also known as ham radio, is the use of radio frequency radio spectrum, spectrum for purposes of non-commercial exchange of messages, wireless experimentation, self-training, private recreation, radiosport, contesting, and emergen ...
6-meter band The 6-meter band is the lowest portion of the very high frequency (VHF) radio spectrum allocated to amateur radio use. The term refers to the average signal wavelength of 6 meters. Although located in the lower portion of the VHF band, it noneth ...
. *108–118 MHz: Air navigation beacons VOR and Instrument Landing System localizer. *118–137 MHz:
Airband Airband or aircraft band is the name for a group of frequencies Frequency is the number of occurrences of a repeating event per unit of time. It is also referred to as temporal frequency, which emphasizes the contrast to spatial frequency an ...
for
air traffic control Air traffic control (ATC) is a service provided by ground-based air traffic controllers who direct aircraft on the ground and through controlled airspace, and can provide advisory services to aircraft in non-controlled airspace. The primary purp ...
, AM, 121.5 MHz is emergency frequency *144–146 MHz:
Amateur Radio Amateur radio, also known as ham radio, is the use of radio frequency radio spectrum, spectrum for purposes of non-commercial exchange of messages, wireless experimentation, self-training, private recreation, radiosport, contesting, and emergen ...
2-meter band The 2-meter amateur radio band is a portion of the VHF radio spectrum, comprising frequencies stretching from 144 MHz to 148 MHz in International Telecommunication Union region, International Telecommunication Union region (ITU) Regions 2 ...
(Extends up to 148 MHz in some Regions). *156–174 MHz: VHF maritime mobile band for maritime two-way radio on ships.

# By country

## Australia

The VHF TV 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
NewcastleNewcastle usually refers to either: *Newcastle upon Tyne Newcastle upon Tyne (, ), often simply Newcastle, is the most populous City status in the United Kingdom, city and metropolitan borough in North East England. It forms the Tyneside conurbati ...
, WIN-4
Wollongong Wollongong ( ), informally referred to as "The Gong", is a city located in the Illawarra region of New South Wales New South Wales (abbreviated as NSW) is a States and territories of Australia, state on the Eastern states of Australia, east ...
and
ABC ABC are the first three letters of the Latin script known as the alphabet. ABC or abc may also refer to: Arts, entertainment, and media Broadcasting * American Broadcasting Company, a commercial U.S. TV broadcaster ** Disney–ABC Television ...
NewcastleNewcastle usually refers to either: *Newcastle upon Tyne Newcastle upon Tyne (, ), often simply Newcastle, is the most populous City status in the United Kingdom, city and metropolitan borough in North East England. It forms the Tyneside conurbati ...
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 Ultra high frequency (UHF) is the ITU designation for radio frequencies in the range between 300 megahertz The hertz (symbol: Hz) is the SI derived unit, derived unit of frequency in the International System of Units (SI) and is defin ...

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 channels, 9A and 12, have since been made available and are being used primarily for digital services (e.g.
ABC ABC are the first three letters of the Latin script known as the alphabet. ABC or abc may also refer to: Arts, entertainment, and media Broadcasting * American Broadcasting Company, a commercial U.S. TV broadcaster ** Disney–ABC Television ...
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,

## New Zealand

*44–51, 54–68 MHz:
Band I Band I is a range of radio frequencies within the very high frequency Very high frequency (VHF) is the ITU designation for the range of radio frequency Radio frequency (RF) is the oscillation rate of an Alternating_current, alternating el ...
Television (channels 1–3) *87.5–108 MHz:
Band II Band II is the range of radio frequencies within the very high frequency (VHF) part of the electromagnetic spectrum from 87.5 to 108.0  megahertz (MHz). Radio Band II is primarily used worldwide for FM radio broadcasting. Broadcast tel ...
Band III Band III is the name of the range of radio frequencies within the very high frequency Very high frequency (VHF) is the ITU designation for the range of radio frequency Radio frequency (RF) is the oscillation rate of an Alternating_current, ...
Television (channels 4–11) Until 2013, the four main Free-to-Air TV stations in
New Zealand New Zealand ( mi, Aotearoa ) is an island country in the southwestern Pacific Ocean. It consists of two main landmasses—the North Island () and the South Island ()—and more than 700 List of islands of New Zealand, smaller islands, coveri ...

used the VHF Television bands (
Band I Band I is a range of radio frequencies within the very high frequency Very high frequency (VHF) is the ITU designation for the range of radio frequency Radio frequency (RF) is the oscillation rate of an Alternating_current, alternating el ...
and
Band III Band III is the name of the range of radio frequencies within the very high frequency Very high frequency (VHF) is the ITU designation for the range of radio frequency Radio frequency (RF) is the oscillation rate of an Alternating_current, ...
) to transmit to New Zealand households. Other stations, including a variety of pay and regional free-to-air stations, were forced to broadcast in the
UHF Ultra high frequency (UHF) is the ITU designation for radio frequencies in the range between 300 megahertz The hertz (symbol: Hz) is the SI derived unit, derived unit of frequency in the International System of Units (SI) and is defin ...

band, since the VHF band had been very overloaded with four stations sharing a very small frequency band, which was so overcrowded that one or more channels would not be available in some smaller towns. However, at the end of 2013, all television channels stopped broadcasting on the VHF bands, as New Zealand moved to digital television broadcasting, requiring all stations to either broadcast on UHF or satellite (where UHF was unavailable) utilising the Freeview service. Refer to Australasian television frequencies for more information.

## United Kingdom

British television originally used VHF band I and band III. Television on VHF was in black and white with 405-line format (although there were experiments with all three colour systems-NTSC, PAL, and SECAM-adapted for the 405-line system in the late 1950s and early 60s). British colour television was broadcast on
UHF Ultra high frequency (UHF) is the ITU designation for radio frequencies in the range between 300 megahertz The hertz (symbol: Hz) is the SI derived unit, derived unit of frequency in the International System of Units (SI) and is defin ...

(channels 21–69), beginning in the late 1960s. From then on, TV was broadcast on both VHF and UHF (VHF being a monochromatic downconversion from the 625-line colour signal), with the exception of BBC Two, 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
, as it is in most of the world. Unusually, the UK has an
amateur radio Amateur radio, also known as ham radio, is the use of radio frequency radio spectrum, spectrum for purposes of non-commercial exchange of messages, wireless experimentation, self-training, private recreation, radiosport, contesting, and emergen ...
allocation at 4 metres, 70-70.5 MHz.

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, with various sub-bands.The 42 MHz Segment is still in current use by the California Highway Patrol, New Jersey State Police, Tennessee Highway Patrol, and other state law enforcement agencies. *30–88 MHz: Military VHF frequency modulation, 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 it was moved to 88–108 MHz. *50–54 MHz: Amateur radio
6-meter band The 6-meter band is the lowest portion of the very high frequency (VHF) radio spectrum allocated to amateur radio use. The term refers to the average signal wavelength of 6 meters. Although located in the lower portion of the VHF band, it noneth ...
**50.800–51 MHz: Radio-controlled aircraft (on ten fixed frequencies at 20 kHz spacing) with an Amateur radio licensing in the United States, FCC Amateur Radio Service license, flown under FCC Part 97, rule 97.215. *54–88 MHz, known as "Band I, Band I" internationally; some DTV stations will appear here. See North American broadcast television frequencies **54–72 MHz television, TV channels 2–4 (VHF-Lo) **72–76 MHz: Radio controlled models, industrial remote control, and other devices. Radio-controlled aircraft, Model aircraft operate on 72 MHz while surface models operate on 75 MHz in the US and Canada, air navigation beacons 74.8–75.2 MHz. **76–88 MHz TV channels 5–6 (VHF-Lo) *87.5–108 MHz:
broadcasting (87.9–91.9 non-commercial, 92–108 commercial in the United States) (known as "Band II, Band II" internationally) *108–118 MHz: Air navigation beacons VOR *118–137 MHz:
Airband Airband or aircraft band is the name for a group of frequencies Frequency is the number of occurrences of a repeating event per unit of time. It is also referred to as temporal frequency, which emphasizes the contrast to spatial frequency an ...
for
air traffic control Air traffic control (ATC) is a service provided by ground-based air traffic controllers who direct aircraft on the ground and through controlled airspace, and can provide advisory services to aircraft in non-controlled airspace. The primary purp ...
, AM **121.5 MHz is an emergency frequency *137–138 MHz 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 The 2-meter amateur radio band is a portion of the VHF radio spectrum, comprising frequencies stretching from 144 MHz to 148 MHz in International Telecommunication Union region, International Telecommunication Union region (ITU) Regions 2 ...
amateur radio Amateur radio, also known as ham radio, is the use of radio frequency radio spectrum, spectrum for purposes of non-commercial exchange of messages, wireless experimentation, self-training, private recreation, radiosport, contesting, and emergen ...
*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, though not transmitted aerially, uses a spectrum of frequencies overlapping VHF.

### VHF television

The U.S. Federal Communications Commission, FCC allocated television broadcasting to a channelized roster as early as 1938 with 19 channels. That changed three more times: in 1940 when Channel 19 was deleted and several channels changed frequencies, then in 1946 with television going from 18 channels to 13 channels, again with different frequencies, and finally in 1948 with the removal of Channel 1 (North American TV), Channel 1 (analog channels 2-13 remain as they were, even on cable television). Channels 14-19 later appeared on the UHF band, while channel 1 remains unused.