ARRL Technician Practice Exam

What is meant by the gain of an antenna?

1. The increase in signal strength in a specified direction when compared to a reference antenna

2. The amount of power an antenna can transmit

3. The measure of antenna height

4. The area covered by the antenna's signal

The correct answer is: The increase in signal strength in a specified direction when compared to a reference antenna

The gain of an antenna refers specifically to the increase in signal strength in a specified direction compared to a reference antenna, typically an isotropic radiator or a dipole antenna. This measure expresses how effectively the antenna can direct radio waves in a particular direction, enhancing the signal strength more than the reference would. Antenna gain is usually expressed in decibels (dB) and indicates the antenna's ability to focus energy in a desired direction, which is crucial for maximizing communication range and quality. A higher gain means that the antenna can send and receive signals more efficiently in certain directions, making it a critical factor in antenna design and selection for various applications like amateur radio, cellular communications, and broadcasting. Other choices do not accurately define antenna gain. The power an antenna can transmit relates more to its input power and efficiency rather than its gain. The height of the antenna and the area covered by its signal are physical attributes and operational characteristics but do not specifically convey the concept of gain. Understanding antenna gain is essential for anyone working with radio frequencies, as it directly affects communication effectiveness.