How Sun-Watchers Stopped World War III In 1967
As the Great Storm of 1967 interrupted radio and radar communications, scientists and military leaders scrambled to decipher the cause.
Microwave transmission
Microwave transmission is the transmission of information or energy by electromagnetic waves whose wavelengths are conveniently measured in small numbers of centimetre; these are called microwaves. Th...
Microwave transmission - Wikipedia
Radio spectrum
The radio spectrum is the part of the electromagnetic spectrum from 8.3 kHz to 3000 GHz allocated to some 40 Radiocommunication services in line to the Radio Regulations (RR) of the Internat...
Polar mesospheric summer echoes
Polar mesospheric summer echoes (PMSE) is the phenomenon of anomalous radar echoes found between 80-90 km in altitude from May through early August in the Arctic, and from November through to February...
Co-channel interference
Co-channel interference or CCI is crosstalk from two different radio transmitters using the same frequency. There can be several causes of co-channel radio interference; four examples are listed here....
How Sun-Watchers Stopped World War III In 1967
As the Great Storm of 1967 interrupted radio and radar communications, scientists and military leaders scrambled to decipher the cause.
ITU Model for Indoor Attenuation
The ITU indoor propagation model, also known as ITU model for indoor attenuation, is a radio propagation model that estimates the path loss inside a room or a closed area inside a building delimited b...
Longley–Rice model
The Longley–Rice model (LR) is a radio propagation model: a method for predicting the attenuation of radio signals for a telecommunication link in the frequency range of 20 MHz to 20 GHz. Longley-Rice...
Lowest usable high frequency
The lowest usable high frequency (LUF), in radio transmission, is that frequency in the HF band at which the received field intensity is sufficient to provide the required signal-to-noise ratio for a ...
2-Ray Ground Reflection Model
2-ray Ground Reflected Model is a radio propagation model that predicts path loss when the signal received consists of the line of sight component and multi path component formed predominately by a si...
2-Ray Ground Reflection Model - Wikipedia
Sporadic E propagation
Sporadic E or Es is an unusual form of radio propagation using characteristics of the Earth's ionosphere. Whereas most forms of skywave propagation use the normal and cyclic ionization properties of t...
Mush zone
In mediumwave broadcasting, a mush zone is a region where the ground wave and sky wave from a transmitter are received at approximately equal signal strength, resulting in interference between the two...
Communications blackout
In telecommunications, communications blackouts are
Uptime being a key goal of most communications networks, uninterruptible power supplies and backup generators are typically used to ensure high-...
Sound pressure
Sound pressure or acoustic pressure is the local pressure deviation from the ambient (average, or equilibrium) atmospheric pressure, caused by a sound wave. In air, sound pressure can be measured usin...
Meteor burst communications
Meteor burst communications (MBC), also referred to as meteor scatter communications, is a radio propagation mode that exploits the ionized trails of meteors during atmospheric entry to establish brie...
Meteor burst communications - Wikipedia
Side lobe
In antenna engineering, side lobes or sidelobes are the lobes (local maxima) of the far field radiation pattern that are not the main lobe.The radiation pattern of most antennas shows a pattern of "lo...
Side lobe - Wikipedia
MW DX
MW DX, short for mediumwave DXing, is the hobby of receiving the reception of distant mediumwave (known as AM in North America) radio stations. MW DX is similar to TV and FM DX in that broadcast band ...
Ionospheric reflection
Ionospheric reflection is a bending, through a complex process involving reflection and refraction, of electromagnetic waves propagating in the ionosphere back toward the Earth. The amount of bending ...
Ionospheric reflection - Wikipedia
Magneto-ionic double refraction
In telecommunication, magneto-ionic double refraction is the combined effect of the Earth's magnetic field and atmospheric ionization, whereby a linearly polarized wave entering the ionosphere is spli...
Inversion (meteorology)
In meteorology, an inversion is a deviation from the normal change of an atmospheric property with altitude. It almost always refers to a "temperature inversion," i.e., an increase in temperature with...
Inversion (meteorology) - Wikipedia
Disturbance storm time index
The disturbance storm time (Dst, Kyoto Dst) index is a measure in the context of space weather. It gives information about the strength of the ring current around Earth caused by solar protons and ele...
Power delay profile
The power delay profile (PDP) gives the intensity of a signal received through a multipath channel as a function of time delay. The time delay is the difference in travel time between multipath arriva...
Doppler effect
The Doppler effect (or Doppler shift) is the change in frequency of a wave (or other periodic event) for an observer moving relative to its source. It is named after the Austrian physicist Christian D...
Doppler effect - Wikipedia
Group velocity
The group velocity of a wave is the velocity with which the overall shape of the waves' amplitudes—known as the modulation or envelope of the wave—propagates through space.For example, if a stone is t...
X band
The X band is a segment of the microwave radio region of the electromagnetic spectrum. In some cases, such as in communication engineering, the frequency range of X band is rather indefinitely set at ...
X band - Wikipedia
Frequency-hopping spread spectrum
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...
One Woodland Terminal Model
The ITU terrestrial model for one terminal in woodland is a radio propagation model belonging to the class of foliage models. This model is a successor of the early ITU model.
Applicable to the sc...
Atmospheric dynamo
The Atmospheric dynamo is a pattern of electrical currents that are set up in the Earth's ionosphere by multiple effects, mostly the Sun's solar wind, but also the tides of the Moon and Sun. The curre...
Young model
Young model is a radio propagation model that was built on the data collected on New York City. It typically models the behaviour of cellular communication systems in large cities.
This model is i...