Figure 7.
Possible routes for ground waves.
6.
Direct Wave Component.
The direct wave is that part of the
ground wave that travels directly from the transmitting antenna to
the receiving antenna. The direct wave is limited to line of sight
distances. To increase the range, increase the height of either the
transmitting or receiving antenna.
7.
Ground Reflecting Component. The ground reflected component is
that part of the radio wave that is reflected before it reaches the
receiving antenna.
It may be reflected from the ground or from a
body of water.
When the radio wave is reflected, the phase is
reversed.
This could affect the reliability of communication.
It
could cancel out the radio waves that travel directly to the
receiving antenna.
To minimize the canceling effect, the antenna
should be raised at either end.
8.
Surface Wave Component.
a. The surface wave travels along the Earth's surface.
It
follows the curvature of the earth.
When both the receiving and
transmitting antennas are located close to the earth, the direct and
reflected wave may cancel each other out.
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