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Very high frequency
Very high frequency
(VHF) is the ITU designation[1] for the range of radio frequency electromagnetic waves (radio waves) from 30 to 300 megahertz (MHz), with corresponding wavelengths of ten to one meter. 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
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 kilometers with radio modems, amateur radio, and marine communications. Air traffic control
Air traffic control
communications and air navigation systems (e.g. VOR & ILS) work at distances of 100 kilometers or more to aircraft at cruising altitude. In North America, most of South America and many other parts of the world, VHF Band I was used for the transmission of analog television. As part of the worldwide transition to digital television most countries require broadcasters to transmit television in the VHF range using digital rather than analog format.

Contents

1 Propagation characteristics 2 Line-of-sight calculation 3 Antennas 4 Universal use 5 By country

5.1 Australia 5.2 New Zealand 5.3 United Kingdom 5.4 United States and Canada

5.4.1 VHF television 5.4.2 87.5-87.9 MHz

6 Unlicensed operation 7 See also 8 References

Propagation characteristics[edit] Radio
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 (skywave propagation).[2] They do not follow the contour of the Earth as ground waves and so are blocked by hills and mountains, although because they are weakly refracted (bent) by the atmosphere they can travel somewhat beyond the visual horizon out to about 160 km (100 miles). These characteristics allow the same VHF frequencies to be used by different users in neighboring geographical areas without interference (frequency reuse). They can penetrate building walls and be received indoors, although in urban areas reflections from buildings cause multipath propagation, which can interfere with television reception. Atmospheric radio noise and interference (RFI) from electrical equipment is less of a problem in the band 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-talkies. Occasionally, when conditions are right, VHF waves can travel long distances by tropospheric ducting due to refraction by temperature gradients in the atmosphere. Line-of-sight calculation[edit]

"Rabbit-ears" VHF television antenna (the small loop is a separate 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[citation needed] distance in kilometers =

12.746 ×

A

m

displaystyle sqrt 12.746times A_ m

where

A

m

displaystyle A_ m

is the height of the antenna in meters.[citation needed]

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.[citation needed] The accuracy of these calculations for digital TV signals is being debated.[3] Antennas[edit]

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

By country[edit]

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

Australia[edit] See also: Australasian television frequencies The VHF T V band
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
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
Broadcasting
Authority began a process to move these stations to 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[edit]

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)

Until 2013, the four main Free-to-Air TV stations in New Zealand
New Zealand
used 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, were forced to broadcast in the UHF 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.[4] Refer to Australasian television frequencies
Australasian television frequencies
for more information. United Kingdom[edit]

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British television originally used VHF band I and band III. Television on VHF was in black and white with 405-line
405-line
format (although there were experiments with all three colour systems-NTSC, PAL, and SECAM-adapted for the 405-line
405-line
system in the late 1950s and early 60s). British colour television was broadcast on UHF (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 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[edit] 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 [5] 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
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
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
Airband
for air traffic control, AM, 121.5 MHz is an emergency frequency 137–138 MHz Space research, space operations, meteorological satellite [6] 138–144 MHz: Land mobile, auxiliary civil services, satellite, space research, and other miscellaneous services 144–148 MHz: Amateur radio
Amateur radio
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; 156.8 MHz (Channel 16) is the maritime emergency and contact frequency. 159.81-161.565 MHz railways [7] 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,[8] 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, though not transmitted aerially, uses a spectrum of frequencies overlapping VHF.[9] VHF television[edit] 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).[10] 87.5-87.9 MHz[edit] 87.5-87.9 MHz is a radio frequency which, in most of the world, is used for FM broadcasting. In 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
Pulse 87
franchise, have operated on this frequency as radio stations, though they use television licenses. As a result, FM radio
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
Mountain View, California
and 34-watt translator K200AA in Sun Valley, Nevada. Unlicensed operation[edit] In some countries, particularly the 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.[11] See also[edit]

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[edit]

^ "Rec. ITU-R V.431-7, Nomenclature of the frequency and wavelength bands used in telecommunications" (PDF). ITU. Archived from the original (PDF) on 31 October 2013. Retrieved 20 February 2013.  ^ Seybold, John S. (2005). Introduction to RF Propagation. John Wiley and Sons. pp. 9–10. 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. Archived from the original on 17 October 2011. 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. ^ "Change to the law to allow the use of low power FM transmitters for MP3 players". Ofcom. 23 November 2006. Archived from the original on 7 August 2011. Retrieved 2 October 2012. 

v t e

Broadcast bands with Roman numeral designations

VHF

Band I Band II Band III

UHF

Band IV Band V

SHF

Band VI

v t e

Radio spectrum
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 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

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

← higher frequencies       longer wavelengths →

Visible (optical)

Violet Blue Green Yellow Orange 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 VHF HF MF LF VLF ULF SLF ELF

Wavelength
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 Mass media Mobile phone Optical telecommunication Optical telegraphy Pager Photophone Prepay mobile phone Radio Radiotelephone Satellite communications Semaphore Smartphone Smoke signals Telecommunications history Telautograph Telegraphy Teleprinter
Teleprinter
(teletype) Telephone The Telephone Cases Television Timeline of communication technology Undersea telegraph line Videoconferencing Videophone Videotelephony Whistled language

Pioneers

Edwin Howard Armstrong John Logie Baird Paul Baran Alexander Graham Bell Tim Berners-Lee Jagadish Chandra Bose 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 Antonio Meucci Radia Perlman Alexander Stepanovich Popov Johann Philipp Reis Nikola Tesla Camille Tissot Alfred Vail Charles Wheatstone Vladimir K. Zworykin

Transmission media

Coaxial cable Fiber-optic communication

Optical fiber

Free-space optical communication Molecular communication Radio
Radio
waves Transmission line

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 FidoNet Internet ISDN LAN Mobile NGN NPL network Public Switched Telephone Radio Telecommunications equipment Television Telex WAN Wireless World Wide Web

Category Portal

v t e

Analog television
Analog television
broadcasting topics

Systems

180-line 405-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 PAL PAL-M PAL-S PALplus SECAM

Video

Back porch and front porch Black level Blanking level Chrominance Chrominance
Chrominance
subcarrier Colorburst Color killer Color TV 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
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 Transposer

Frequencies & Bands

Frequency
Frequency
offset Microwave
Microwave
transmission Television
Television
channel frequencies 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 VIT signals Zero reference pulse

Artifacts

Dot crawl Ghosting Hanover bars Sparklies

v t e

Analog and digital audio broadcasting

Terrestrial

Radio
Radio
modulation

AM FM COFDM

Frequency
Frequency
allocations

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

Digital systems

CAM-D DAB/DAB+ DRM/DRM+ FMeXtra HD Radio CDR DVB-T2
DVB-T2
Lite

Satellite

Frequency
Frequency
allocations

C band Ku band L band S band

Digital systems

ADR DAB-S DVB-SH S-DMB SDR

Commercial radio providers

1worldspace Sirius XM Holdings SiriusXM Canada

Codecs

AAC AMR-WB+ HDC HE-AAC MPEG-1 Audio Layer II

Subcarrier signals

AMSS DirectBand PAD RDS/RBDS SCA/SCMO DARC

Related topics

Technical (audio)

Audio data compression Audio signal processing

Technical ( AM stereo
AM stereo
formats)

Belar C-QUAM Harris Kahn-Hazeltine Magnavox

Technical (emission)

AM broadcasting AM expanded band Cable radio Digital radio Error detection and correction FM broadcast band FM broadcasting Multipath propagation Shortwave relay station

Cultural

History of radio International broadcasting

Comparison of radio systems

Authority control

GND: 41316

.