Continuous wave.
A continuous-wave transmitter sends out a
continuous flow of radio frequency energy except when disrupted by a
switch or a key.
Counterpoise.
A conductor used as a substitute for ground in an
antenna system. It is commonly referred to as an artificial ground.
Coupling. The association of two electrical circuits in such a way
that energy can be transferred from one circuit to the other.
Frequency.
The repetition
rate of
a periodically recurring
It is commonly
measured
in hertz, kilohertz, or
megahertz.
Hertz.
A unit of frequency equal to 1 cycle per second.
Polarization. The condition of light or radiant energy in which the
transverse vibrations of the wave are confined to one plane or
direction. The process of being positive or negative with respect
to some reference point.
Radiation. The process of sending energy into space, as in the case
of electromagnetic waves radiated from an antenna.
Resonance. An electrical condition in which the natural frequency
of the circuit is the same as the frequency of the incoming signal.
A conductor or system of conductors used to
carry electrical energy from its source to its load.
Wave.
A single cycle of a periodic disturbance, such as a radio
wave.
Wavelength.
The distance in meters traveled by a wave during the
time interval of one complete cycle (1 hertz).
Wavelength (in meters)
=
velocity (in meters)
frequency (in hertz)
4.
FUNCTIONS OF ANTENNAS.
In principle, an antenna is a rod or wire
which radiates or receives radio frequency signals (radio waves).
Good
radio communication depends on resonant transmitting and receiving antennas-
For best
results, especially when transmitting, an antenna must be (electrically)
about one-half as long as the frequency wavelength on which it is operating.
This
electrical relationship is
maintained in
tactical
radios
by
automatically adjusting (tuning) the electrical length of the antenna
instead of changing (shortening or lengthening) the physical length of the
antenna every time the operator changes frequency.
Antenna AS-1729/VRC,
issued with the AN/VRC-46, -47, and -49 radio sets, is an example of an
electrically tuned antenna.
a. Half-wave antenna. A half-wavelength antenna (commonly referred to
as a half-wave antenna) is a single wire that is electrically equal to one-
half the wavelength of the signal it transmits. The wire can be installed
either
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