ARRL Technician Practice Exam

How does increasing the height of an antenna typically affect its performance?

1. It decreases its gain

2. It reduces radiation resistance

3. It enhances signal coverage

4. It shortens the antenna length

The correct answer is: It enhances signal coverage

Increasing the height of an antenna typically enhances signal coverage due to several factors related to how radio waves propagate. As the height of an antenna is raised, it can transmit and receive signals over a greater distance. This improvement occurs because higher antennas are more effective at sending signals above ground clutter and obstacles, such as buildings and trees, which can obstruct the line of sight and cause signal degradation. Higher antennas can also benefit from a more favorable angle of radiation, allowing for better performance in terms of both horizontal and vertical coverage patterns. This means that the signals are transmitted farther and with greater efficiency, particularly in line-of-sight communications. In contrast, decreasing gain, reducing radiation resistance, or shortening the antenna length do not align with the effects of increasing antenna height. Instead, a taller antenna typically increases gain and radiation resistance while optimizing the pattern for better communication range. Thus, enhancing signal coverage is the most accurate description of the impact that increased antenna height has on performance.