Radio waves are electromagnetic waves occurring on the radio frequency portion of the electromagnetic spectrum. A common use is to transport information through the atmosphere or outer space without wires. Radio waves are distinguished from other kinds of electromagnetic waves by their wavelength, a relatively long wavelength in the electromagnetic spectrum. Electromagnetic waves can be imagined as a self-propagating transverse oscillating wave of electric and magnetic fields. ... It has been suggested that this article or section be merged with Radio waves. ... Legend γ = Gamma rays HX = Hard X-rays SX = Soft X-Rays EUV = Extreme ultraviolet NUV = Near ultraviolet Visible light NIR = Near infrared MIR = Moderate infrared FIR = Far infrared Radio waves EHF = Extremely high frequency (Microwaves) SHF = Super high frequency (Microwaves) UHF = Ultra high frequency VHF = Very high frequency HF = High... The ASCII codes for the word Wikipedia represented in binary, the numeral system most commonly used for encoding computer information. ... A wire is a single, usually cylindrical, elongated strand of drawn metal. ... For other uses, see Wavelength (disambiguation). ... In most modern usages of the word spectrum, there is a unifying theme of between extremes at either end. ...

What Makes Radio Waves?

Diagram of the electric (E) and magnetic (H) fields of Radio Waves emanating from a radio transmitting antenna (small dark vertical line in the center). The E and H fields are perpendicular as implied by the phase diagram in the lower right.

Radio waves are usually produced by electric current alternating at radio frequency flowing in a special purpose conductor, called an antenna. Antenna dimensions must generally be comparable to wavelength to work efficiently. Very long waves are not practical because of the enormous antennas needed to produce them, although they are sometimes produced by lightning. Radio waves are also produced by cosmic phenomena in deep space. Actually, any kind of reciprocating motion of electric charges or magnets can produce radio waves if it is fast enough. Although very impractical, even a person waving a charged stick very fast can produce faint radio waves. Image File history File links Download high-resolution version (929x585, 140 KB) Copied from Radio Telephony for Amateurs by Ballantine 1922. ... Image File history File links Download high-resolution version (929x585, 140 KB) Copied from Radio Telephony for Amateurs by Ballantine 1922. ... A Yagi-Uda beam antenna Short Wave Curtain Antenna (Moosbrunn, Austria) A building rooftop supporting numerous dish and sectored mobile telecommunications antennas (Doncaster, Victoria, Australia) An antenna is a transducer designed to transmit or receive radio waves which are a class of electromagnetic waves. ... The Goldstone Deep Space Communications Complex (GDSCC) —commonly called the Goldstone Observatory— is located in Californias Mojave Desert (USA). ...

Propagation of radio waves

Propagation is a term that describes the travel of electromagnetic waves, there being three principle main modes of propagation. The first is a straight line travel: the manner that radio waves travel through deep space (ignoring the slight deviations caused by gravity under the theory of relativity). A second way is skip, which is bouncing between the surface of the earth and the ionosphere. Frequencies between 3 MHz and 30 MHz are most reliable for this kind of propagation, called High Frequency. The third way is to hug the surface of the earth as it curves around. Radio waves of very low frequency most often travel this way. Two-dimensional analogy of space-time curvature described in General Relativity. ... In radio propagation, skip is when a radio signal is reflected or refracted by the atmosphere or ionosphere, and returns to Earth in an unexpectedly far-away place. ... Relationship of the atmosphere and ionosphere The ionosphere is the uppermost part of the atmosphere, distinguished because it is ionized by solar radiation. ...

Rough plot of Earth's atmospheric transmittance (or opacity) to various wavelengths of electromagnetic radiation, including radio waves.

Image File history File links Download high resolution version (1650x1049, 189 KB)Plot of the transmittance/opacity of the atmosphere to electromagnetic radiation. ... Image File history File links Download high resolution version (1650x1049, 189 KB)Plot of the transmittance/opacity of the atmosphere to electromagnetic radiation. ...

Historical Discovery

Radio waves were first predicted by mathematical work done in 1865 by James Clerk Maxwell. Maxwell noticed wave-like properties of light and similarities in electrical and magnetic observations and proposed equations that described light waves and radio waves as waves of electromagnetism that travel in space. In 1887 Heinrich Hertz demonstrated the reality of Maxwell's electromagnetic waves by experimentally generating radio waves in his laboratory. Many inventions followed making practical use of radio waves to transfer information through space. James Clerk Maxwell (13 June 1831 – 5 November 1879) was a Scottish mathematician and theoretical physicist from Edinburgh, Scotland, UK. His most significant achievement was aggregating a set of equations in electricity, magnetism and inductance — eponymously named Maxwells equations — including an important modification (extension) of the Ampères... Heinrich Rudolf Hertz (February 22, 1857 - January 1, 1894) was the German physicist and mechanician for whom the hertz, an SI unit, is named. ...

Italian engineer Guglielmo Marconi is generally credited with inventing radio. In 1895 he transmitted a signal 2.4 kilometres in the grounds of his father's property. He patented the first 'wireless telegraphy' system in 1896. Guglielmo Marconi [gue:lmo marko:ni] (25 April 1874 - 20 July 1937) was an Italian inventor of mixed Italian and Irish ethnicity, best known for his development of a radiotelegraph system, which served as the foundation for the establishment of numerous affiliated companies worldwide. ...

Radio Portion of the Electromagnetic Wave Spectrum

Radio waves are divided up into bands by frequency (and corresponding wavelength) as shown in the radio frequency spectrum table below. For other uses, see Wavelength (disambiguation). ... Familiar concepts associated with a frequency are colors, musical notes, radio/TV channels, and even the regular rotation of the earth. ...

Notes This article does not cite any references or sources. ... The International Telecommunication Union (ITU; French: Union internationale des télécommunications, Spanish: Unión Internacional de Telecomunicaciones) is an international organization established to standardize and regulate international radio and telecommunications. ... This article is about the SI unit of frequency. ... A kilometer (Commonwealth spelling: kilometre), symbol: km is a unit of length in the metric system equal to 1,000 metres (from the Greek words χίλια (khilia) = thousand and μέτρο (metro) = count/measure). ... Extremely low frequency (ELF) is the band of radio frequencies from 3 to 30 Hz. ... This article is about the SI unit of frequency. ... Because electromagnetic radiation such as normal radio communication cannot travel through thick conductors such as salt water, communication with submarines when they are submerged is a difficult technological task which requires specific techniques and devices. ... Super Low Frequency (SLF) is the frequency range between 30 hertz and 300 hertz. ... This article is about the SI unit of frequency. ... Because electromagnetic radiation such as normal radio communication cannot travel through thick conductors such as salt water, communication with submarines when they are submerged is a difficult technological task which requires specific techniques and devices. ... Ultra Low Frequency (ULF) is the frequency range between 300 hertz and 3000 hertz. ... This article is about the SI unit of frequency. ... Very low frequency or VLF refers to radio frequencies (RF) in the range of 3 to 30 kHz. ... A kilohertz (kHz) is a unit of frequency equal to 1,000 hertz (1,000 cycles per second). ... The toe of an avalanche in Alaskas Kenai Fjords. ... Photo of a heart rate monitor (made by Polar) showing chest strap and watch Photo of a Prevention MF-180 strapless heart rate monitor This article refers to a device used by laypersons. ... ‹ The template below has been proposed for deletion. ... Low Frequency or LF refers to Radio Frequencies (RF) in the range of 30–300 kHz. ... A kilohertz (kHz) is a unit of frequency equal to 1,000 hertz (1,000 cycles per second). ... Radio navigation is the application of radio frequencies to determining a position on the earth. ... A radio clock A radio clock is a clock that is synchronized by a time code bit stream transmitted by a radio transmitter connected to a time standard such as an atomic clock. ... This article does not cite any references or sources. ... Medium frequency (MF) refers to radio frequencies (RF) in the range of 300 kHz to 3000 kHz. ... A kilohertz (kHz) is a unit of frequency equal to 1,000 hertz (1,000 cycles per second). ... For other uses, see M (disambiguation). ... Mediumwave radio transmissions (sometimes called Medium frequency or MF) are those between the frequencies of 300 kHz and 3000 kHz. ... High frequency (HF) radio frequencies are between 3 and 30 MHz. ... MegaHertz (MHz) is the name given to one million (106) Hertz, a measure of frequency. ... A solid-state, analog shortwave receiver Shortwave radio operates between the frequencies of 3 MHz (3,000 kHz) and 30 MHz (30,000 kHz) [1] and came to be referred to as such in the early days of radio because the wavelengths associated with this frequency range were shorter than... Amateur radio station with modern solid-state transceiver featuring LCD display and DSP capabilities Amateur radio, often called ham radio, is a hobby that uses various types of radio broadcasting equipment to communicate with other radio amateurs for public service, recreation and self-training. ... Very high frequency (VHF) is the radio frequency range from 30 MHz (wavelength 10 m) to 300 MHz (wavelength 1 m). ... MegaHertz (MHz) is the name given to one million (106) Hertz, a measure of frequency. ... FM radio is a broadcast technology invented by Edwin Howard Armstrong that uses frequency modulation to provide high-fidelity sound over broadcast radio. ... This article is about the radio frequency. ... MegaHertz (MHz) is the name given to one million (106) Hertz, a measure of frequency. ... A millimetre (American spelling: millimeter), symbol mm is an SI unit of length that is equal to one thousandth of a metre. ... This article is about the type of Electromagnetic radiation. ... The notebook is connected to the wireless access point using a PC card wireless card. ... Bluetooth logo This article is about the electronic protocol named after Harald Bluetooth Gormson. ... Over fifty GPS satellites such as this NAVSTAR have been launched since 1978. ... Microwave Slang for small waves, like at a beach, often used by surfers. ... A gigahertz is a billion hertz or a thousand megahertz, a measure of frequency. ... This article is about the type of Electromagnetic radiation. ... The notebook is connected to the wireless access point using a PC card wireless card. ... For other uses, see Radar (disambiguation). ... Extremely high frequency is the highest radio frequency band. ... A gigahertz is a billion hertz or a thousand megahertz, a measure of frequency. ... The Very Large Array, a radio interferometer in New Mexico, USA Radio astronomy is a subfield of astronomy that studies celestial objects in the radio frequency portion of the electromagnetic spectrum. ... This article or section does not cite its references or sources. ... A gigahertz is a billion hertz or a thousand megahertz, a measure of frequency. ...

• Above 300 GHz, the absorption of electromagnetic radiation by Earth's atmosphere is so great that the atmosphere is effectively opaque to higher frequencies of electromagnetic radiation, until the atmosphere becomes transparent again in the so-called infrared and optical window frequency ranges.
• The ELF, SLF, ULF, and VLF bands overlap the AF (audio frequency) spectrum, which is approximately 20–20,000 Hz. However, sounds are transmitted by atmospheric compression and expansion, and not by electromagnetic energy.
• The SHF and EHF bands are sometimes not considered to be a part of the radio spectrum, forming their own microwave spectrum.

Electromagnetic waves can be imagined as a self-propagating transverse oscillating wave of electric and magnetic fields. ... For other uses, see Infrared (disambiguation). ... An audio frequency (abbreviation: AF) is any frequency from about 20 hertz to about 20 kilohertz, which is the approximate range of sound frequencies that is audible to humans. ... Radio frequency, or RF, refers to that portion of the electromagnetic spectrum in which electromagnetic waves can be generated by alternating current fed to an antenna. ... This article is about the type of Electromagnetic radiation. ...

Named frequency bands

General

Broadcast Frequencies:

• Longwave AM Radio = 148.5 - 283.5 kHz (LF)
• Mediumwave AM Radio = 530kHz - 1710kHz (MF)
• TV Band I (Channels 2 - 6) = 54MHz - 88MHz (VHF)
• FM Radio Band II = 88MHz - 108MHz (VHF)
• TV Band III (Channels 7 - 13) = 174MHz - 216MHz (VHF)
• TV Bands IV & V (Channels 14 - 69) = 470MHz - 806MHz (UHF) [1]

For more information see the NTIA frequency allocation chart: http://www.ntia.doc.gov/osmhome/allochrt.html

Amateur radio frequencies

The range of allowed frequencies vary between countries. These are just some of the more common bands, often collectively termed shortwave. The article amateur radio contains another list. A solid-state, analog shortwave receiver Shortwave radio operates between the frequencies of 3 MHz (3,000 kHz) and 30 MHz (30,000 kHz) [1] and came to be referred to as such in the early days of radio because the wavelengths associated with this frequency range were shorter than... Amateur radio station with modern solid-state transceiver featuring LCD display and DSP capabilities Amateur radio, often called ham radio, is a hobby that uses various types of radio broadcasting equipment to communicate with other radio amateurs for public service, recreation and self-training. ...

IEEE US

L band (20-cm radar long-band) is a portion of the microwave band of the electromagnetic spectrum ranging roughly from 0. ... The S band ranges from 2 to 4 GHz. ... C band (compromise band) is a portion of electromagnetic spectrum in the microwave range of frequencies ranging from 4 to 6 GHz. ... The X band (3-cm radar spot-band) of the microwave band of the electromagnetic spectrum roughly ranges from 5. ... Combatants Allied powers: China France Great Britain Soviet Union United States and others Axis powers: Germany Italy Japan and others Commanders Chiang Kai-shek Charles de Gaulle Winston Churchill Joseph Stalin Franklin Roosevelt Adolf Hitler Benito Mussolini Hideki Tōjō Casualties Military dead: 17,000,000 Civilian dead: 33,000... A fire-control system is a computer, often mechanical, which is designed to assist a weapon system in hitting its target. ... A drawing of different reticles used in telescopic sights. ... The Ku band (kay-yoo kurz-under band) is a portion of the electromagnetic spectrum in the microwave range of frequencies ranging from 11 to 18 GHz. ... K band is a portion of the electromagnetic spectrum in the microwave range of frequencies ranging between 12 to 63 GHz. ... The Ka band (kurz-above band) is a portion of the K band of the microwave band of the electromagnetic spectrum. ... The V band (vee-band) of the electromagnetic spectrum ranges from 50 to 75 GHz. ... The W band of the microwave part of the electromagnetic spectrum and ranges from 75 to 111 GHz. ... ABCs redirects here, for the Alien Big Cats, see British big cats. ...

EU, NATO, US ECM Frequency Designations

A Band were a British musical collective formed in Nottingham in the late 1980s. ... The B band is the range of radio frequencies from 250 MHz to 500 MHz in the electromagnetic spectrum. ... C band (compromise band) is a portion of electromagnetic spectrum in the microwave range of frequencies ranging from 4 to 6 GHz. ... The D band is the range of radio frequencies from 1 GHz to 2 GHz in the electromagnetic spectrum. ... The E band is the range of radio frequencies from 2 GHz to 3 GHz in the electromagnetic spectrum. ... The F band is the range of radio frequencies from 3 GHz to 4 GHz in the electromagnetic spectrum. ... The G band in the modern (NATO/EU) sense is the range of radio frequencies from 4 GHz to 6 GHz in the electromagnetic spectrum. ... The H band is the range of radio frequencies from 6 GHz to 8 GHz in the electromagnetic spectrum. ... The I band is the range of radio frequencies from 8 GHz to 10 GHz in the electromagnetic spectrum. ... The J band is the range of radio frequencies from 10 GHz to 20 GHz in the electromagnetic spectrum. ... K band is a portion of the electromagnetic spectrum in the microwave range of frequencies ranging between 12 to 63 GHz. ... L band (20-cm radar long-band) is a portion of the microwave band of the electromagnetic spectrum ranging roughly from 0. ... The M band is the range of radio frequencies from 60 GHz to 100 GHz in the electromagnetic spectrum. ...

References

• ITU-R Recommendation V.431: Nomenclature of the frequency and wavelength bands used in telecommunications. International Telecommunication Union, Geneva.

• ANSI/IEEE Standard: Letter designations for radar-frequency bands.

• AFR 55-44/AR 105-86/OPNAVINST 3430.9A/MCO 3430.1, 27 October 1964 superseded by AFR 55-44/AR 105-86/OPNAVINST 3430.1A/MCO 3430.1A, 6 December 1978: Performing Electronic Countermeasures in the United States and Canada, Attachment 1,ECM Frequency Authorizations.

The International Telecommunication Union (ITU; French: Union internationale des télécommunications, Spanish: Unión Internacional de Telecomunicaciones) is an international organization established to standardize and regulate international radio and telecommunications. ...

See also

Radio Portal

• Radio propagation
• Frequency allocation
• Radio astronomy
• Radio electronics

Image File history File links Radio_icon. ... Radio propagation is a term used to explain how radio waves behave when they are transmitted, or are propagated from one point on the Earth to another. ... The electromagnetic spectrum is an aspect of the physical world, like land, water, and air. ... The Very Large Array, a radio interferometer in New Mexico, USA Radio astronomy is a subfield of astronomy that studies celestial objects in the radio frequency portion of the electromagnetic spectrum. ... Radio electronics is the sub-field of electrical engineering concerning itself with the class of electronic circuits which receive or transmit radio signals. ... Radio frequency, or RF, refers to that portion of the electromagnetic spectrum in which electromagnetic waves can be generated by alternating current fed to an antenna. ... Extremely low frequency (ELF) is the band of radio frequencies from 3 to 30 Hz. ... Super Low Frequency (SLF) is the frequency range between 30 hertz and 300 hertz. ... Ultra Low Frequency (ULF) is the frequency range between 300 hertz and 3000 hertz. ... Very low frequency or VLF refers to radio frequencies (RF) in the range of 3 to 30 kHz. ... Low Frequency or LF refers to Radio Frequencies (RF) in the range of 30–300 kHz. ... Medium frequency (MF) refers to radio frequencies (RF) in the range of 300 kHz to 3000 kHz. ... High frequency (HF) radio frequencies are between 3 and 30 MHz. ... Very high frequency (VHF) is the radio frequency range from 30 MHz (wavelength 10 m) to 300 MHz (wavelength 1 m). ... This article is about the radio frequency. ... Microwave Slang for small waves, like at a beach, often used by surfers. ... Extremely high frequency is the highest radio frequency band. ...

Legend γ = Gamma rays HX = Hard X-rays SX = Soft X-Rays EUV = Extreme ultraviolet NUV = Near ultraviolet Visible light NIR = Near infrared MIR = Moderate infrared FIR = Far infrared Radio waves EHF = Extremely high frequency (Microwaves) SHF = Super high frequency (Microwaves) UHF = Ultra high frequency VHF = Very high frequency HF = High... This article is about electromagnetic radiation. ... In the NATO phonetic alphabet, X-ray represents the letter X. An X-ray picture (radiograph) taken by Röntgen An X-ray is a form of electromagnetic radiation with a wavelength approximately in the range of 5 pm to 10 nanometers (corresponding to frequencies in the range 30 PHz... For other uses, see Ultraviolet (disambiguation). ... “Visible light” redirects here. ... For other uses, see Infrared (disambiguation). ... Electromagnetic waves sent at terahertz frequencies, known as terahertz radiation, terahertz waves, terahertz light, T-rays, T-light, T-lux and THz, are in the region of the electromagnetic spectrum between 300 gigahertz (3x1011 Hz) and 3 terahertz (3x1012 Hz), corresponding to the wavelength range starting at submillimeter (<1 millimeter... This article is about the type of Electromagnetic radiation. ... “Visible light” redirects here. ... Violet (named after the flower violet) is used in two senses: first, referring to the color of light at the short-wavelength end of the visible spectrum, approximately 380–420 nanometres (this is a spectral color). ... For other uses, see Blue (disambiguation). ... For other uses, see Green (disambiguation). ... A yellow Tulip. ... The orange, a fruit from which the modern name of the orange colour comes. ... For other uses, see Red (disambiguation). ... This article is about the type of Electromagnetic radiation. ... The W band of the microwave part of the electromagnetic spectrum and ranges from 75 to 111 GHz. ... The V band (vee-band) of the electromagnetic spectrum ranges from 50 to 75 GHz. ... The Ka band (kurz-above band) is a portion of the K band of the microwave band of the electromagnetic spectrum. ... K band is a portion of the electromagnetic spectrum in the microwave range of frequencies ranging between 12 to 63 GHz. ... The Ku band (kay-yoo kurz-under band) is a portion of the electromagnetic spectrum in the microwave range of frequencies ranging from 11 to 18 GHz. ... The X band (3-cm radar spot-band) of the microwave band of the electromagnetic spectrum roughly ranges from 5. ... C band (compromise band) is a portion of electromagnetic spectrum in the microwave range of frequencies ranging from 4 to 6 GHz. ... The S band ranges from 2 to 4 GHz. ... L band (20-cm radar long-band) is a portion of the microwave band of the electromagnetic spectrum ranging roughly from 0. ... Radio frequency, or RF, refers to that portion of the electromagnetic spectrum in which electromagnetic waves can be generated by alternating current fed to an antenna. ... Extremely high frequency is the highest radio frequency band. ... Microwave Slang for small waves, like at a beach, often used by surfers. ... This article is about the radio frequency. ... Very high frequency (VHF) is the radio frequency range from 30 MHz (wavelength 10 m) to 300 MHz (wavelength 1 m). ... High frequency (HF) radio frequencies are between 3 and 30 MHz. ... Medium frequency (MF) refers to radio frequencies (RF) in the range of 300 kHz to 3000 kHz. ... Low Frequency or LF refers to Radio Frequencies (RF) in the range of 30–300 kHz. ... Very low frequency or VLF refers to radio frequencies (RF) in the range of 3 to 30 kHz. ... Ultra Low Frequency (ULF) is the frequency range between 300 hertz and 3000 hertz. ... Super Low Frequency (SLF) is the frequency range between 30 hertz and 300 hertz. ... Extremely low frequency (ELF) is the band of radio frequencies from 3 to 30 Hz. ... For other uses, see Wavelength (disambiguation). ... This article is about the type of Electromagnetic radiation. ... A solid-state, analog shortwave receiver Shortwave radio operates between the frequencies of 3 MHz (3,000 kHz) and 30 MHz (30,000 kHz) [1] and came to be referred to as such in the early days of radio because the wavelengths associated with this frequency range were shorter than... Mediumwave radio transmissions serves as the most common band for broadcasting. ... This article does not cite any references or sources. ...

References

• James Clerk Maxwell, "A Dynamical Theory of the Electromagnetic Field", Philosophical Transactions of the Royal Society of London 155, 459-512 (1865).

• Heinrich Hertz, "Electric waves: being researches on the propagation of electric action with finite velocity through space". Cornell University Library Historical Monographs Collection. {Reprinted by} Cornell University Library Digital Collections