What does the term "bandwidth" refer to in radio communications?

The term "bandwidth" in radio communications specifically refers to the width of the frequency range over which a signal can be transmitted effectively without significant distortion. It quantifies the difference between the highest and lowest frequencies in this range, which determines how much information can be transmitted at once.

When a signal occupies a certain bandwidth, it means that it utilizes a specific range of frequencies, allowing for efficient communication. This concept is essential in ensuring that signals can be transmitted and received cleanly, minimizing overlap with other signals and reducing interference. A wider bandwidth usually allows for higher data rates and better quality of communication.

In this context, the other options do not accurately define bandwidth. While maximum power levels can affect how a signal is transmitted, they do not describe the frequency range. Modulation techniques relate to how information is encoded onto a carrier wave but do not define bandwidth. Similarly, the distance a signal can travel pertains to propagation characteristics rather than the frequency range itself. Therefore, understanding bandwidth as the frequency range helps clarify its critical role in radio communications.