44 relations: American Radio Relay League, Amplitude modulation, Angle modulation, Aurora, Automatic link establishment, Coherence bandwidth, Coherence time, Comb filter, Constant envelope, Decibel, Delay spread, Diplomatic Wireless Service, Dual-tone multi-frequency signaling, Earth–Moon–Earth communication, Eb/N0, Fading, Forward error correction, Frequency modulation, Frequency-hopping spread spectrum, Frequency-shift keying, High frequency, In-band signaling, Institution of Electrical Engineers, Intermodulation, Intersymbol interference, Joseph Hooton Taylor Jr., Letter beacon, M-ary transmission, Multi-frequency signaling, Multipath propagation, Near vertical incidence skywave, Noisy-channel coding theorem, Olivia MFSK, OZ7IGY, Phreaking, PSK31, Radio Society of Great Britain, Radioteletype, Signal-to-noise ratio, Signaling (telecommunications), Skywave, Ultra high frequency, Very high frequency, WSJT (amateur radio software).
The American Radio Relay League (ARRL) is the largest membership association of amateur radio enthusiasts in the USA.
Amplitude modulation (AM) is a modulation technique used in electronic communication, most commonly for transmitting information via a radio carrier wave.
Angle modulation is a class of carrier modulation that is used in telecommunications transmission systems.
An aurora (plural: auroras or aurorae), sometimes referred to as polar lights, northern lights (aurora borealis) or southern lights (aurora australis), is a natural light display in the Earth's sky, predominantly seen in the high-latitude regions (around the Arctic and Antarctic).
Automatic Link Establishment, commonly known as ALE, is the worldwide de facto standard for digitally initiating and sustaining HF radio communications.
Coherence bandwidth is a statistical measurement of the range of frequencies over which the channel can be considered "flat", or in other words the approximate maximum bandwidth or frequency interval over which two frequencies of a signal are likely to experience comparable or correlated amplitude fading.
For an electromagnetic wave, the coherence time is the time over which a propagating wave (especially a laser or maser beam) may be considered coherent.
In signal processing, a comb filter is a filter implemented by adding a delayed version of a signal to itself, causing constructive and destructive interference.
Constant envelope is achieved when a sinusoidal waveform reaches equilibrium in a specific system.
The decibel (symbol: dB) is a unit of measurement used to express the ratio of one value of a physical property to another on a logarithmic scale.
In telecommunications, the delay spread is a measure of the multipath richness of a communications channel.
The Diplomatic Wireless Service (DWS) was the name of the communications system set up for the British Foreign Office by Brigadier Richard Gambier-Parry, the first Foreign Office Director of Communications, in the latter part of 1945.
Dual-tone multi-frequency signaling (DTMF) is an in-band telecommunication signaling system using the voice-frequency band over telephone lines between telephone equipment and other communications devices and switching centers.
Earth–Moon–Earth communication (EME), also known as moon bounce, is a radio communications technique that relies on the propagation of radio waves from an Earth-based transmitter directed via reflection from the surface of the Moon back to an Earth-based receiver.
Eb/N0 (the energy per bit to noise power spectral density ratio) is an important parameter in digital communication or data transmission.
In wireless communications, fading is variation or the attenuation of a signal with various variables.
In telecommunication, information theory, and coding theory, forward error correction (FEC) or channel coding is a technique used for controlling errors in data transmission over unreliable or noisy communication channels.
In telecommunications and signal processing, frequency modulation (FM) is the encoding of information in a carrier wave by varying the instantaneous frequency of the wave.
Frequency-hopping spread spectrum (FHSS) is a method of transmitting radio signals by rapidly switching a carrier among many frequency channels, using a pseudorandom sequence known to both transmitter and receiver.
Frequency-shift keying (FSK) is a frequency modulation scheme in which digital information is transmitted through discrete frequency changes of a carrier signal.
High frequency (HF) is the ITU designation for the range of radio frequency electromagnetic waves (radio waves) between 3 and 30 megahertz (MHz).
In telecommunications, in-band signaling is the sending of control information within the same band or channel used for voice or video.
The Institution of Electrical Engineers (IEE, pronounced I-E-E) was a British professional organisation of electronics, electrical, manufacturing, and Information Technology professionals, especially electrical engineers.
Intermodulation (IM) or intermodulation distortion (IMD) is the amplitude modulation of signals containing two or more different frequencies, caused by nonlinearities in a system.
In telecommunication, intersymbol interference (ISI) is a form of distortion of a signal in which one symbol interferes with subsequent symbols.
Joseph Hooton Taylor Jr. (born March 29, 1941) is an American astrophysicist and Nobel Prize in Physics laureate for his discovery with Russell Alan Hulse of a "new type of pulsar, a discovery that has opened up new possibilities for the study of gravitation.".
Letter beacons are radio transmissions of uncertain origin and unknown purpose, consisting of only a single repeating Morse code letter.
An M-ary transmission is a type of digital modulation where instead of transmitting one bit at a time, two or more bits are transmitted simultaneously.
In telephony, multi-frequency signaling (MF) is a signaling system that was introduced by the Bell System after World War II.
In wireless telecommunications, multipath is the propagation phenomenon that results in radio signals reaching the receiving antenna by two or more paths.
Near vertical incidence skywave, or NVIS, is a skywave radio-wave propagation path that provides usable signals in the range between groundwave and conventional skywave distances—usually 30–400 miles (50–650 km).
In information theory, the noisy-channel coding theorem (sometimes Shannon's theorem or Shannon's limit), establishes that for any given degree of noise contamination of a communication channel, it is possible to communicate discrete data (digital information) nearly error-free up to a computable maximum rate through the channel.
Olivia MFSK is an amateur radioteletype protocol, using multiple frequency-shift keying (MFSK) and designed to work in difficult (low signal-to-noise ratio plus multipath propagation) conditions on shortwave bands.
OZ7IGY is a Danish amateur radio beacon, and the world's oldest VHF and UHF amateur radio beacon and active since the International Geophysical Year in 1957.
Phreaking is a slang term coined to describe the activity of a culture of people who study, experiment with, or explore telecommunication systems, such as equipment and systems connected to public telephone networks.
PSK31 or "Phase Shift Keying, 31 Baud", also BPSK31 and QPSK31, is a popular computer-sound card-generated radioteletype mode, used primarily by amateur radio operators to conduct real-time keyboard-to-keyboard chat, most often using frequencies in the high frequency amateur radio bands (near-shortwave).
The Radio Society of Great Britain (RSGB), first founded in 1913 as the London Wireless Club, is the United Kingdom's recognised national society for amateur radio operators.
Radioteletype (RTTY) is a telecommunications system consisting originally of two or more electromechanical teleprinters in different locations connected by radio rather than a wired link.
Signal-to-noise ratio (abbreviated SNR or S/N) is a measure used in science and engineering that compares the level of a desired signal to the level of background noise.
In telecommunication, signaling has the following meanings.
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.
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 decimeter.
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 to one meter.
WSJT is a computer program used for weak-signal radio communication between amateur radio operators.