18WuD2x

18 aircraft flutter • airwaves
aircraft flutter Rapid, repetitive fading and intensifying
of a received radio or television signal, resulting
from reflections of the signal by passing
aircraft.
aircraft station A nonautomatic radio communications
station installed on an aircraft.
air-dielectric coax A special type of COAXIAL CA-
BLE designed to have minimum loss. The space
between inner and outer conductors is mostly
empty (i.e., air-filled). Some such cables are
sealed and filled with an inert gas. The inner conductor
is held away from the inner wall of the
outer conductor by beads, washers, or a spiralwound
filament of high-grade dielectric material,
such as polyethylene.
air environment Pertaining to communications
equipment aboard aircraft.
airflow The path or movement of air in, through, or
around an electronic device or piece of equipment—especially
pertaining to an AIR-COOLED
COMPONENT.
air gap 1. A narrow space between two parts of a
magnetic circuit (e.g., the gap in the core of a filter
choke). Often, this gap is filled with a nonmagnetic
material, such as plastic, for
mechanical support. 2. The space between two or
more magnetically coupled or electrostatically
coupled components. 3. A device that gets its
name from the narrow gap between two small
metal balls, needle points, or blunt rod tips
therein. When an applied voltage is sufficiently
high, a spark discharges across the gap.
air/ground control radio station A station for
aeronautical telecommunications related to the
operation and control of local aircraft.
air-insulated line 1. An open-wire feeder or transmission
line. Typically, the line consists of two
parallel wires held apart by separators (bars or
rods of high-grade dielectric material) situated at
wide intervals. 2. AIR-DIELECTRIC COAX.
air-moving device A mechanical device, such as a
specially designed fan or blower, used to facilitate
air cooling of electronic components.
airport beacon A radio or light beacon that marks
the location of an airport.
airport control station A station that provides
communications between an airport control
tower and aircraft in the vicinity.
airport surveillance radar An air-traffic-control
radar that scans the airspace within about 60
miles (approximately 100 kilometers) of an airport,
and displays in the control tower the location
of all aircraft below a certain altitude and all
obstructions in the vicinity.
air-position indicator An airborne computer system
that, using airspeed, aircraft heading, and
elapsed time, furnishes a continuous indication
of the position of the aircraft. The indication is
affected by high-altitude winds. Compare
GROUND-POSITION INDICATOR.
air-to-air communication Radio transmission
from one aircraft to another in flight. Compare
AIR-TO-GROUND COMMUNICATION and
GROUND-TO-AIR COMMUNICATION.
air-to-ground communication Radio transmission
from an aircraft in flight to a station located
on the ground. Compare AIR-TO-AIR COMMUNI-
CATION and GROUND-TO-AIR COMMUNICA-
TION.
air-to-ground radio frequency The carrier frequency,
or band of such frequencies, allocated for
transmissions from an aircraft to a ground station.
airwaves 1. Radio waves. The term is slang, but is
widely used. It probably came from the public’s