Very High Frequency (VHF)

Very High Frequency (VHF)
Name	Very High Frequency
Abbreviation	VHF
Frequency range	30–300 MHz
Wavelength	10 m–1 m
First use	1930s
Applications	Broadcast, aviation, maritime, amateur radio, land mobile

Contents

Very High Frequency (VHF) Very High Frequency occupies the 30–300 MHz radio spectrum and underpins broadcast, aviation, maritime, and land mobile services. Its role connects historic developments by Guglielmo Marconi, Edwin Armstrong, Reginald Fessenden, and institutions such as Bell Labs, RCA, BBC, AT&T with modern deployments by NATO, Federal Aviation Administration, International Telecommunication Union, and European Broadcasting Union.

Overview

VHF denotes the electromagnetic band between 30 and 300 megahertz established through coordination by the International Telecommunication Union and early experiments at Massachusetts Institute of Technology, University of Cambridge, Imperial College London, Yale University, and Stanford University. Early broadcasters like BBC and NBC adopted VHF for FM transmission following research by Edwin Armstrong and demonstrations at events involving David Sarnoff, while maritime operators tied VHF to institutions such as the United States Coast Guard and Royal Navy. Technological milestones at Bell Labs, RCA, and Marconi Company shaped antenna design, frequency stabilisation, and modulation schemes later standardized by bodies including ITU-R and European Conference of Postal and Telecommunications Administrations.

Frequency allocation for VHF is governed globally by the International Telecommunication Union and regionally by authorities like the Federal Communications Commission, Ofcom, ANFR, ACMA, and ARCEP. Bandplans partition VHF among services such as FM broadcasting authorized by National Association of Broadcasters, aeronautical communications regulated by the Federal Aviation Administration and Civil Aviation Authority (United Kingdom), maritime channels overseen by the International Maritime Organization and International Telecommunication Union, and amateur allocations administered by American Radio Relay League and Radio Society of Great Britain. Military and public safety allocations involve coordination with organizations such as NATO, Department of Defense (United States), Ministry of Defence (United Kingdom), and national ministries of transport and interior. Regional agreements like the European Common Allocation Table and treaties arising from World Radiocommunication Conference shape channelization, spacing, and licensing frameworks.

VHF propagation is dominated by line-of-sight and tropospheric phenomena studied by researchers at NASA, NOAA, JAXA, CNR, and university groups at University of Michigan, California Institute of Technology, ETH Zurich, Tsinghua University, and University of Tokyo. Groundwave, direct wave, and tropospheric scatter mechanisms interact with terrain and atmospheric layers described in work by Reginald Fessenden and later refined in publications from ITU-R, IEEE Communications Society, Royal Society, and American Geophysical Union. Ionospheric effects such as sporadic E, studied after observations during World War II and research programs involving CERN and Naval Research Laboratory, occasionally permit long-distance VHF propagation, while ducting and atmospheric refractivity studied in projects by Met Office and European Space Agency alter coverage patterns.

VHF is central to FM broadcasting pioneered by BBC and Radio France, aeronautical communications managed by Federal Aviation Administration and Eurocontrol, maritime VHF channels standardized by the International Maritime Organization, emergency services coordinated by agencies like FEMA and Emergency Management Australia, and amateur radio operations organized by American Radio Relay League, Radio Society of Great Britain, and Japan Amateur Radio League. Additional uses include telemetry for space programs such as NASA and Roscosmos, low-power two-way radio systems used by companies like Motorola Solutions and ICOM Incorporated, VHF television standards defined by bodies like Advanced Television Systems Committee and adopted by broadcasters such as CBC, NHK, ABC (Australia), and ZDF. Public service communications for police and fire services in nations including United Kingdom, United States, Germany, and Japan often utilize VHF allocations under national licensing regimes.

VHF transmitters and receivers trace design lineage through innovations at Bell Labs, RCA, Hewlett-Packard, Motorola, Kenwood Corporation, and Yaesu. Antenna types such as dipoles, Yagis, and ground-plane arrays were developed and refined in laboratories at Massachusetts Institute of Technology and Delft University of Technology and deployed by broadcasters like BBC and navies including the Royal Navy. Modulation and processing equipment incorporate technologies standardized by IEEE, 3GPP for coexistence, and codec developments by ITU-T; test and measurement instruments originate from firms such as Tektronix and Rohde & Schwarz. Advances in digital signal processing at MIT Media Lab, Stanford University, and ETH Zurich enabled software-defined radios used by DARPA, European Defence Agency, and amateur experimenters under societies like ARRL.

Regulation of VHF involves international coordination through the International Telecommunication Union and national enforcement by agencies such as the Federal Communications Commission, Ofcom, Australian Communications and Media Authority, and Industry Canada. Spectrum auctions and licensing conducted by Ofcom and FCC impact broadcasters like iHeartMedia and Bauer Media Group while safety standards for human exposure reference guidelines set by the World Health Organization, International Commission on Non-Ionizing Radiation Protection, and national health agencies including CDC and Public Health England. Interference management, emergency allocation, and coordination during events such as World Radiocommunication Conference and disaster responses led by United Nations Office for the Coordination of Humanitarian Affairs require cross-border collaboration among telecommunications ministries, military authorities like NATO, and broadcasting unions such as European Broadcasting Union.

Category:Radio frequency bands