ARRL Technician Practice Exam

What describes a simple dipole mounted so the conductor is parallel to the Earth's surface?

1. A vertically polarized antenna

2. A horizontally polarized antenna

3. A circularly polarized antenna

4. An isotropic antenna

The correct answer is: A horizontally polarized antenna

A dipole antenna that is mounted parallel to the Earth's surface is considered a horizontally polarized antenna because the orientation of the dipole elements determines the polarization of the radiated signal. When the dipole's conductors are laid out horizontally, it primarily radiates electromagnetic waves in a horizontal plane. Horizontally polarized antennas are effective for long-distance communication, as they typically have a lower angle of radiation, which enhances their ability to propagate signals over the horizon due to ground reflection. This alignment with the Earth provides better performance for long-range communications, particularly at certain frequencies. In contrast, vertically polarized antennas, such as vertical dipoles, have elements oriented perpendicular to the ground, which is not the case here. Circularly polarized antennas involve a different radiation pattern altogether, wherein the phase of the signal changes in a circular manner. Lastly, an isotropic antenna is an idealized antenna that radiates equally in all directions, which doesn't specifically apply to the described situation of a simple dipole. Thus, the correct description for a simple dipole mounted parallel to the Earth's surface is that it functions as a horizontally polarized antenna.