ARRL Technician Practice Exam

What results from the fact that skip signals refracted from the ionosphere are elliptically polarized?

1. Only horizontally polarized antennas can be used

2. Only vertically polarized antennas can be used

3. Either vertically or horizontally polarized antennas may be used for transmission or reception

4. A special type of antenna must be used

The correct answer is: Either vertically or horizontally polarized antennas may be used for transmission or reception

The phenomenon of skip signals being elliptically polarized means that these signals do not have a fixed polarization and can contain components of both vertical and horizontal polarization. As a result, both vertically and horizontally polarized antennas are capable of receiving or transmitting these signals effectively. This flexibility stems from the nature of the elliptical polarization, allowing antennas with different orientations to be successful in capturing the varied polarization states of the incoming signals. This characteristic is particularly beneficial in amateur radio as it allows for enhanced communication ability without the need for specialized antennas. Since the polarization of the received signal can change due to factors such as distance, ionospheric conditions, and angles of incidence, being able to use either type of antenna increases the chances of successful communication. Both types of antennas have their advantages, but the presence of elliptically polarized signals ensures that operators are not restricted to a single polarization type, thus fostering versatility in antenna usage for effective radio communication.