2-6
Figure 2-4.—E and H components of induction and radiation fields.
Q1. Which two composite fields (composed of E and H fields) are associated with every antenna?
Q2. What composite field (composed of E and H fields) is found stored in the antenna?
Q3. What composite field (composed of E and H fields) is propagated into free space?
RADIO WAVES
An energy wave generated by a transmitter is called a RADIO WAVE. The radio wave radiated into
space by the transmitting antenna is a very complex form of energy containing both electric and magnetic
fields. Because of this combination of fields, radio waves are also referred to as ELECTROMAGNETIC
RADIATION.
This discussion will explain the Earth's atmosphere and its effect on radio waves. All the principles
of wave motion that were discussed in chapter 1 also apply to radio waves.
NOTE: The term radio wave is not limited to communications equipment alone. The term applies to
all equipment that generate signals in the form of electromagnetic energy.
COMPONENTS OF RADIO WAVES
The basic shape of the wave generated by a transmitter is that of a sine wave. The wave radiated out
into space, however, may or may not retain the characteristics of the sine wave.
