COAXIAL LINE—A type of transmission line that
contains two concentric conductors.
COLLINEAR ARRAY—An array with all the
elements in a straight line. Maximum radiation
is perpendicular to the axis of the elements.
COMBINATION ARRAY—An array system that
uses the characteristics of more than one array.
Also known as ARRAY OF ARRAYS.
COMPLEX WAAE—A wave produced by combining
two or more pure tones at the same time.
CONDUCTANCE—The opposite of resistance in
transmission lines.
The minute amount of
resistance that is present in the insulator of a
transmission line.
CONNECTED ARRAY—see DRIVEN ARRAY
COPPER LOSS—Power loss in copper conductors
caused by the internal resistance of the conductors
to current flow. Also know as 12R LOSS.
CORNER-REFLECTOR ANTENNA—A half-wave
antenna with a reflector consisting of two flat
metal surfaces meeting at an angle behind the
radiator.
COUNTERPOISE—A network of wire that is
connected to a quarter-wave antenna at one end
and provides the equivalent of an additional ¼
wavelength.
COUPLING DEVICE—A coupling coil that con-
nects the transmitter to the feeder.
CREST (TOP)—The peak of the positive alternation
(maximum value above the line) of a wave.
CRITICAL ANGLE—The maximum angle at which
radio waves can be transmitted and still be
refracted back to earth.
CRITICAL FREQUENCY—The maximum fre-
quency at which a radio wave can be transmitted
vertically and still be refracted back to earth.
CURRENT-FEED METHOD—See CENTER-FEED
METHOD.
C U R R E N T S T A N D I N G - W A V E R A T I O
(ISWR)—The ratio of maximum to minimum
current along a transmission line.
CUTOFF FREQUENCY—The frequency at which
the attenuation of a waveguide increases sharply
and below which a traveling wave in a given
mode cannot be maintained. A frequency with
a half wavelength that is greater than the wide
dimension of a waveguide.
CYCLE—One complete alternation of a sine wave
that has a maximum value above and a maximum
value below the reference line.
DAMPING—Reduction of energy by absorption.
DENSITY—(1) The compactness of a substance;
(2) Mass per unit volume.
DETECTOR—The device that responds to a wave
or disturbance.
DIELECTRIC HEATING—The heating of an
insulating material by placing it in a high
frequency electric field.
DIELECTRIC LOSSES—The losses resulting from
the heating effect on the dielectric material
between conductors.
DIELECTRIC CONSTANT—The ratio of a given
dielectric to the dielectric value of a vacuum.
DIFFRACTION—The bending of the paths of waves
when the waves meet some form of obstruction.
DIPOLE—A common type of half-wave antenna
made from a straight piece of wire cut in half.
Each half operates at a quarter wavelength of the
output.
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