The boundary beyond the natural horizon in which
radio waves cannot be propagated over the earth's
(1) A form of radiant energy that can neither be seen
nor felt. (2) An electromagnetic wave generated by a
A longitudinal wave that has been expanded or rarefied
(made less dense) as it moves away from the source.
The object that responds to a wave or disturbance.
Same as detector.
The device used to pick up an RF signal from space.
See OUTPUT END.
The property of interchangeability of the same antenna
for transmitting and receiving.
A graph in which straight-line axes (horizontal and
vertical) are perpendicular.
The position a particle of matter would occupy if it were
not disturbed by wave motion.
(1) The wave that reflects back from a medium. (2)
Waves traveling from the load back to the generator on
a transmission line. (3) The wave moving back to the
sending end of a transmission line after reflection has
Waves that are neither transmitted nor absorbed, but
are reflected from the surface of the medium they
The parasitic element of an array that causes maximum
energy radiation in a direction toward the driven
The changing of direction as a wave leaves one medium
and enters another medium of a different density.
The reception and retransmission of radio waves caused
vibrations are the same as the natural frequency (of a
cavity). The vibrations reinforce each other.