Pertaining to sounds capable of being heard by the
(1) The object that produces waves or disturbance. (2)
The name given to the end of a two-wire transmission
line that is connected to a source.
Reception of radio waves by two or more antennas
spaced some distance apart.
A radio wave that travels directly from the transmitter
(1) The entire range of electromagnetic waves. (2)
VISIBLE. The range of electromagnetic waves that
stimulate the sense of sight. (3) ELECTROMAGNETIC.
The entire range of electromagnetic waves arranged in
order of their frequencies.
sporadic E layer
Irregular cloud-like patches of unusually high
ionization. Often forms at heights near the normal E
Insulator used with transmission lines and antennas to
keep the parallel wires separated.
The distribution of voltage and current formed by the
incident and reflected waves which have minimum and
maximum points on a resultant wave that appears to
The ratio of the maximum (voltage, current) to the
minimum (voltage, current) of a transmission line.
Measures the perfection of the termination of the line.
Has little effect on radio waves.
Short section of a transmission line used to match the
also be used to produce desired phase relationships
between connected elements of an antenna.
An irregular ionospheric disturbance that can totally
Speed greater than the speed of sound.
A radio wave that travels along the contours of the
earth, thereby being highly attenuated.