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High frequency, the Glossary

High frequency (HF) is the ITU designation for the band of radio waves with frequency between 3 and 30 megahertz (MHz).^[1]

54 relations: Amateur radio, Antenna (radio), Aurora, Automatic link establishment, Automatic repeat request, Broadband over power lines, Citizens band radio, Coastal ocean dynamics applications radar, Continuous wave, Critical frequency, Curtain array, Decametre, Dipole antenna, Electromagnetic spectrum, Frequency, Frequency of optimum transmission, Global Maritime Distress and Safety System, Hertz, High Frequency Internet Protocol, High-frequency Active Auroral Research Program, International Telecommunication Union, Internet, Ionization, Ionosphere, Line-of-sight propagation, Log-periodic antenna, Lowest usable high frequency, Maximum usable frequency, Medium frequency, Morse code, Over-the-horizon radar, Polarization (waves), Quad antenna, Radio control, Radio propagation, Radio spectrum, Radio wave, Random wire antenna, Refraction, Rhombic antenna, Satellite, Season, Shortwave radio, Single-sideband modulation, Skywave, Solar cycle, Space weather, Standardization agreement, Sunspot, Terminator (solar), ... Expand index (4 more) »

Amateur radio

Amateur radio, also known as ham radio, is the use of the radio frequency spectrum for purposes of non-commercial exchange of messages, wireless experimentation, self-training, private recreation, radiosport, contesting, and emergency communications.

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Antenna (radio)

In radio engineering, an antenna (American English) or aerial (British English) is the interface between radio waves propagating through space and electric currents moving in metal conductors, used with a transmitter or receiver.

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Aurora

An aurora (aurorae or auroras), also commonly known as the northern lights (aurora borealis) or southern lights (aurora australis), is a natural light display in Earth's sky, predominantly seen in high-latitude regions (around the Arctic and Antarctic).

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Automatic link establishment

Automatic Link Establishment, commonly known as ALE, is the worldwide de facto standard for digitally initiating and sustaining HF radio communications.

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Automatic repeat request

Automatic repeat request (ARQ), also known as automatic repeat query, is an error-control method for data transmission that uses acknowledgements (messages sent by the receiver indicating that it has correctly received a message) and timeouts (specified periods of time allowed to elapse before an acknowledgment is to be received) to achieve reliable data transmission over an unreliable communication channel.

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Broadband over power lines

Broadband over power lines (BPL) is a method of power-line communication (PLC) that allows relatively high-speed digital data transmission over public electric power distribution wiring.

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Citizens band radio

Citizens band radio (CB radio) is a land mobile radio system, a system allowing short-distance one-to-many bidirectional voice communication among individuals, using two-way radios operating near 27 MHz (or the 11-m wavelength) in the high frequency or shortwave band.

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Coastal ocean dynamics applications radar

Coastal ocean dynamics applications radar (CODAR) is a type of portable, land-based, high frequency (HF) radar developed between 1973 and 1983 at NOAA's Wave Propagation Laboratory in Boulder, Colorado.

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Continuous wave

A continuous wave or continuous waveform (CW) is an electromagnetic wave of constant amplitude and frequency, typically a sine wave, that for mathematical analysis is considered to be of infinite duration.

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Critical frequency

In telecommunication, the term critical frequency has the following meanings.

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Curtain array

Curtain arrays, a class of large multielement directional radio transmitting wire antennas, are used in the short-wave radio bands.

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Decametre

A decametre (International spelling as used by the International Bureau of Weights and Measures and by most English speaking countries, United States spelling dekameter or decameter), symbol dam ("da" for the SI prefix deca-, "m" for the SI unit metre), is a unit of length in the International System of Units (SI) equal to ten metres.

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Dipole antenna

In radio and telecommunications a dipole antenna or doublet is one of the two simplest and most widely-used types of antenna; the other is the monopole.

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Electromagnetic spectrum

The electromagnetic spectrum is the full range of electromagnetic radiation, organized by frequency or wavelength.

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Frequency

Frequency (symbol f), most often measured in hertz (symbol: Hz), is the number of occurrences of a repeating event per unit of time.

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Frequency of optimum transmission

Frequency of optimum transmission (FOT), in the transmission of radio waves via ionospheric reflection, is the highest effective (i.e. working) frequency that is predicted to be usable for a specified path and time for 90% of the days of the month.

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Global Maritime Distress and Safety System

The Global Maritime Distress and Safety System (GMDSS) is a worldwide system for automated emergency signal communication for ships at sea developed by the United Nations' International Maritime Organization (IMO) as part of the SOLAS Convention.

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Hertz

The hertz (symbol: Hz) is the unit of frequency in the International System of Units (SI), equivalent to one event (or cycle) per second.

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High Frequency Internet Protocol

High Frequency Internet Protocol (HFIP or HF-IP) is usually associated with Automatic Link Establishment and HF radio data communications.

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High-frequency Active Auroral Research Program

The High-frequency Active Auroral Research Program (HAARP) is a University of Alaska Fairbanks program which researches the ionosphere – the highest, ionized part of Earth's atmosphere.

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International Telecommunication Union

The International Telecommunication Union (ITU)French: Union Internationale des Télécommunications is a specialized agency of the United Nations responsible for many matters related to information and communication technologies.

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Internet

The Internet (or internet) is the global system of interconnected computer networks that uses the Internet protocol suite (TCP/IP) to communicate between networks and devices.

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Ionization

Ionization (or ionisation specifically in Britain, Ireland, Australia and New Zealand) is the process by which an atom or a molecule acquires a negative or positive charge by gaining or losing electrons, often in conjunction with other chemical changes.

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Ionosphere

The ionosphere is the ionized part of the upper atmosphere of Earth, from about to above sea level, a region that includes the thermosphere and parts of the mesosphere and exosphere.

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Line-of-sight propagation

Line-of-sight propagation is a characteristic of electromagnetic radiation or acoustic wave propagation which means waves can only travel in a direct visual path from the source to the receiver without obstacles.

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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 designed to operate over a wide band of frequencies.

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Lowest usable high frequency

The lowest usable high frequency (LUF), in radio transmission, is a frequency in the HF band at which the received field intensity is sufficient to provide the required signal-to-noise ratio for a specified time period, e.g., 0100 to 0200 UTC, on 90% of the undisturbed days of the month.

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Maximum usable frequency

In radio transmission, maximum usable frequency (MUF) is the highest radio frequency that can be used for transmission between two points on Earth by reflection from the ionosphere (skywave or skip) at a specified time, independent of transmitter power.

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Medium frequency

Medium frequency (MF) is the ITU designation for radio frequencies (RF) in the range of 300 kilohertz (kHz) to 3 megahertz (MHz). High frequency and Medium frequency are radio spectrum.

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Morse code

Morse code is a telecommunications method which encodes text characters as standardized sequences of two different signal durations, called dots and dashes, or dits and dahs.

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Over-the-horizon radar

Over-the-horizon radar (OTH), sometimes called beyond the horizon radar (BTH), is a type of radar system with the ability to detect targets at very long ranges, typically hundreds to thousands of kilometres, beyond the radar horizon, which is the distance limit for ordinary radar.

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Polarization (waves)

italics (also italics) is a property of transverse waves which specifies the geometrical orientation of the oscillations.

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Quad antenna

A quad antenna is a type of directional wire radio antenna used on the HF and VHF bands.

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Radio control

Radio control (often abbreviated to RC) is the use of control signals transmitted by radio to remotely operate a device.

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Radio propagation

Radio propagation is the behavior of radio waves as they travel, or are propagated, from one point to another in vacuum, or into various parts of the atmosphere.

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Radio spectrum

The radio spectrum is the part of the electromagnetic spectrum with frequencies from 3 Hz to 3,000 GHz (3 THz).

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Radio wave

Radio waves are a type of electromagnetic radiation with the lowest frequencies and the longest wavelengths in the electromagnetic spectrum, typically with frequencies below 300 gigahertz (GHz) and wavelengths greater than, about the diameter of a grain of rice.

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Random wire antenna

A random wire antenna is a radio antenna consisting of a long wire suspended above the ground, whose length does not bear a particular relation to the wavelength of the radio waves used, but is typically chosen more for convenient fit between the available supports, or the length of wire at hand, rather than selecting length to be resonant on any particular frequency.

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Refraction

In physics, refraction is the redirection of a wave as it passes from one medium to another.

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Rhombic antenna

A rhombic antenna is made of four sections of wire suspended parallel to the ground in a diamond or "rhombus" shape.

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Satellite

A satellite or artificial satellite is an object, typically a spacecraft, placed into orbit around a celestial body.

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Season

A season is a division of the year based on changes in weather, ecology, and the number of daylight hours in a given region.

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Shortwave radio

Shortwave radio is radio transmission using radio frequencies in the shortwave bands (SW). High frequency and shortwave radio are radio spectrum.

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Single-sideband modulation

In radio communications, single-sideband modulation (SSB) or single-sideband suppressed-carrier modulation (SSB-SC) is a type of modulation used to transmit information, such as an audio signal, by radio waves.

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Skywave

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 atmosphere.

See High frequency and Skywave

Solar cycle

The solar cycle, also known as the solar magnetic activity cycle, sunspot cycle, or Schwabe cycle, is a nearly periodic 11-year change in the Sun's activity measured in terms of variations in the number of observed sunspots on the Sun's surface.

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Space weather

Space weather is a branch of space physics and aeronomy, or heliophysics, concerned with the varying conditions within the Solar System and its heliosphere.

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Standardization agreement

In NATO, a standardization agreement (STANAG, redundantly: STANAG agreement) defines processes, procedures, terms, and conditions for common military or technical procedures or equipment between the member countries of the alliance.

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Sunspot

Sunspots are temporary spots on the Sun's surface that are darker than the surrounding area.

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Terminator (solar)

A terminator or twilight zone is a moving line that divides the daylit side and the dark night side of a planetary body.

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Very high frequency

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 meters to one meter. High frequency and Very high frequency are radio spectrum.

See High frequency and Very high frequency

References

[1] https://en.wikipedia.org/wiki/High_frequency

Also known as HF radio, High-frequency.

, Very high frequency, Wavelength, Yagi–Uda antenna, 2182 kHz.

High frequency, the Glossary

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References