3. A wavelength is the distance traveled by a wave during the time
interval of __________________________________________________________
4. Waves are radiated from an antenna at a speed of ____________ meters
5. To operate properly, an antenna should be electrically about ________
the wavelength of the frequency being transmitted.
one complete hertz.
power is delivered to the antenna. Two electrical fields are set up by this
One is the inducting field, which is associated with
stored energy; and the other is the radiation field, which moves into space
at nearly the speed of light. At the antenna, both these fields are strong
(depending on the power delivered to the antenna).
rapidly loses strength, and only the radiation field remains a short
component and a magnetic component (Fig 4).
These components make up the
electromagnetic field which is responsible for the transmission of
electromagnetic energy through space.
This field, as it travels through
space, is commonly referred to as a radio wave. Thus, a radio wave may be
described as a moving electromagnetic field, having velocity in the
direction of travel and with components of electrical intensity and magnetic
intensity arranged at right angles to each other (Fig 4).
Components of electromagnetic waves (vertical antenna).