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Radic
Radic Rapidly deployable integrated command and
control system, links navies to Nadge.
Radil ROCC/Awacs digital information link.
Radint, radint Radar intelligence.
radio 1 Use of EM radiation between about 5 kHz and
3 THz to convey information.
2 Qualifying adjective denoting that a height above
ground has been measured by radio altimeter, thus
‘50 ft *’.
radioactive ionization gauge Measuring device in which
ions produced by radiation (usually alpha particles) from
radioactive source discharge a capacitor.
radioactivity 1 Spontaneous disintegration of nuclei of
unstable isotope yielding alpha and/or beta particles,
often accompanied by gamma radiation.
2 Number of spontaneous disintegrations per unit mass
per unit time, usually measured in curies.
radioactivity concentration guide Published values
(DoD, NATO etc) of quantities of listed radioisotopes
permissible per unit volume of air and water for continuous
consumption.
radio altimeter Instrument, invariably of CW FM type,
giving readout of height AGL by time-varying frequency
and measuring difference in frequency of received waves,
this being proportional to time and hence to height.
Sometimes called radar altimeter.
radio approach aids Those which assist landing in bad
visibility, notably ILS, MLS; also called radio or electronic
landing aids.
radio astronomy Study of radio emissions received by
Earth, esp. those which can be associated with source of
EM emissions on visible, X-ray or other wavelengths.
radio bands Artificially divided segments of the EM
spectrum, listed in Appendix 2.
radio beacon Fixed ground station emitting RF signals,
esp. those containing identifying information, which
enable mobile stations to determine their position relative
to it.
radio beam Transmitted by directional antenna to maximize
radiated power at long range.
radio bearing Usually, angle between apparent direction
of fixed station and a reference direction, eg, true or
magnetic N. Hence true **, magnetic **.
radio biology Often written as one word, study of effects
of radiation on life.
radio channel One band of frequencies sufficient for
practical radio communication; sum of emission bandwidth,
sideband spread (interference guard bands) and
tolerance for frequency variation.
radio check Request to ground station to transmit to
confirm audibility [readability].
radiochemistry Chemistry of radioactive materials.
radio command Command guidance using a radio link.
radio compass Originally, fixed-loop receiver with which
aircraft could home on to any selected fixed station. Later
superseded by ADF and other navaids.
radio control Vague, but generally means control of
vehicle trajectory with commands transmitted over radio
link.
radio countermeasures Those branches or activities of
ECM concerned with telecommunications.
radio coupling box Inputs ADF, VOR, ILS, etc, to
autopilot.
radio deception Use of radio to deceive enemy; includes
radiolocation
sending false despatches, using deceptive headings and
employing enemy callsigns (DoD, IADB).
radio detection Detection of object’s presence by radio,
without information on position.
radio determination satellite system Satellite system
which enables receiver stations to determine position,
velocity or other characteristics by propagation of radio
waves.
radio direction-finding See direction finding.
radio direction-finding database Aggregate of information,
provided by air and surface means, necessary to
support radio D/F operations to produce fixes on target
transmitters/emitters.
radio duct Shallow quasi-horizontal layer(s) in atmosphere
wherein temperature and moisture gradients result
in abnormally high refraction lapse rate, causing RF
signals to become trapped within layer (see anomalous
propagation, skip effect).
radio energy That which propagates at radio
frequencies.
radio facility chart Original series of US airway maps
based on radio range; name still common for modern air
maps showing all facilities, airways, control zones, TMAs,
etc.
radio fix 1 Fix of mobile station, eg aircraft, obtained by
use of radio navaid, esp. by traditional crossings of
position lines.
2 Geographical location of friendly or, esp., enemy
emitter obtained by various ESM and D/F techniques.
radio frequencies Abb. RF, those EM frequencies used
for radio or related purposes. Common-use subdivisions
are: VLF, below 30 kHz; LF, 30–300 kHz; MF, 300
kHz–3 MHz; HF, 3–30 MHz; VHF, 30–300 MHz; UHF,
300 MHz–3 GHz; SHF, 3–30 GHz; EHF, 30–300 GHz;
unnamed, 300 GHz–3 THz. See Appendix 2.
radio goniometer See direction-finder.
radiography Photography using X-rays, gamma rays or
other ionizing radiation; important NDT method, often
using radiation source inside test object and film outside.
radio guard Radio station, eg aircraft, which listens out
on assigned frequencies and handles traffic and records
transmissions.
radio guidance Guidance or navigation system using
radio waves, eg point-source aids, area coverage (R-Nav),
global (Omega) and command methods.
radio height Height above ground measured by radio
altimeter.
radio hole Direction of propagation suffering abnormal
attenuation or fading, usually caused by local refraction.
radio horizon At any location, line along which direct
rays from RF transmitter become tangential to Earth’s
surface; extends beyond visual horizon because of atmospheric
refraction, and varies according to whether
propagation is sub-, normal or super-standard.
radio-inertial guidance Various systems combining inertial
and radio tracking and/or command (probably obs.).
radio interferometer Interferometer operating at RF.
radioisotope Unstable isotope that decays spontaneously,
emitting radiation.
radioisotope thermoelectric generator Self-contained
power system in which a radioisotope is used to heat one
junction in a circuit containing dissimilar metals and thus
generate sustained electricity.
radiolocation Original UK name for radar.
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