Page 31 - The Illustrated Dictionary of Electronics

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16 admittance • affirmative

admittance Symbol, Y. Unit, siemens (formerly aeronautical fixed service station A station that
mho). The property denoting the comparative operates in the aeronautical fixed service.
ease with which an alternating current flows aeronautical ground station A land station that
through a circuit or device. Admittance is the re- provides communication between aircraft and
ciprocal of impedance (Z): Y = 1/Z. ground stations.
adp 1. Abbreviation of AMMONIUM DIHYDROGEN aeronautical marker-beacon signal A distinctive
PHOSPHATE, a piezoelectric compound used for signal that designates a small area above a beacon
sonar crystals. 2. Abbreviation of AUTOMATIC transmitting station for aircraft navigation.
DATA PROCESSING. aeronautical marker-beacon station A land sta-
adsorption Adhesion of a thin layer of molecules of tion that transmits an aeronautical marker-
one substance to the surface of another without beacon signal.
absorption. An example is adsorption of water to aeronautical mobile service A radio service con-
the surface of a dielectric. This term is often con- sisting of communications between aircraft, and
fused with ABSORPTION because the spellings of between aircraft and ground stations.
the two words are almost identical. Compare AB- aeronautical radio-beacon station An aeronauti-
SORPTION. cal radio-navigation land station that transmits
adu Abbreviation of automatic dialing unit. signals used by aircraft and other vehicles to de-
advanced-class license An amateur-radio license termine their position.
conveying all operating privileges, except for a few aeronautical radionavigation services Services
small bands that are allocated to extra-class li- provided by stations transmitting signals used in
censees. The second-highest class of amateur li- the navigation of aircraft.
cense. aeronautical radio service A service that encom-
advance information Data published prior to the passes aircraft-to-aircraft, aircraft-to-ground,
actual production or availability of a manufac- and ground-to-aircraft communications impor-
tured component, circuit, or system. Advance in- tant to the operation of aircraft.
formation is often only an approximate reflection aeronautical station A station on land, and occa-
of the expected characteristics of a device. sionally aboard ship, operating in the aeronauti-
advance wire A resistance wire used in thermo- cal mobile service.
couples and precision applications. It is an alloy of Aeronautical Telecommunication Agency The
copper and nickel, which has high resistivity and agency that administers the operation of stations
a negligible temperature coefficient of resistance. in the aeronautical radio service.
aeolight A glow lamp using a cold cathode and a aeronautical telecommunications Collectively,
mixture of inert gases. Because its illumination all of the electronic and nonelectronic communi-
can be regulated with an applied signal voltage, it cations used in the aeronautical service.
is sometimes used as a modulation indicator for aeronautical utility land station A ground sta-
motion-picture sound recording. tion in an airport control tower that provides
aerial See ANTENNA. communications having to do with the control of
aerial cable A wire or cable run through the air, us- aircraft and other vehicles on the ground.
ing support structures, such as towers or poles. aeronautical utility mobile station At an airport,
aerodiscone antenna A miniature discone an- a mobile station that communicates with aero-
tenna designed for use on aircraft. nautical utility land stations and with aircraft
aerodynamics The science dealing with forces ex- and other vehicles on the ground.
erted by air and other gases in motion—especially aerophare See RADIO BEACON.
upon bodies (such as aircraft) moving through aerospace 1. The region encompassing the earth’s
these gases. atmosphere and extraterrestrial space. 2. Per-
aerogram See RADIOGRAM. taining to transport and travel in the earth’s at-
aeromagnetic Pertaining to terrestrial magnetism, mosphere and in outer space. This includes
as surveyed from a flying aircraft. aircraft, orbiting space vessels, and interplane-
aeronautical advisory station A civil defense and tary spacecraft.
advisory communications station in service for AES Abbreviation for Audio Engineering Society.
the use of private aircraft stations. AEW Abbreviation of airborne (or aircraft) early
aeronautical broadcasting service The special warning.
service that broadcasts information regarding air aF Abbreviation of ATTOFARAD.
navigation and meteorological data pertinent to AF Abbreviation of AUDIO FREQUENCY.
aircraft operation. AFC 1. Abbreviation of AUTOMATIC FREQUENCY
aeronautical broadcast station A station of the CONTROL. 2. Abbreviation of AUDIO-FRE-
aeronautical broadcasting service. QUENCY CHOKE.
aeronautical fixed service A fixed radio service affirmative In voice communications, a word often
that transmits information regarding air naviga- used for “yes”—especially when interference is
tion and flight safety. present or signals are weak.