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

The term 'bandwidth' in radio communications specifically refers to the range of frequencies used for transmission. This concept is integral to understanding how radio waves carry information. Bandwidth determines how much data can be transmitted in a given amount of time, with a wider bandwidth allowing for more information to be sent simultaneously. For instance, in frequency modulation (FM) radio, the bandwidth available for each station determines the quality of sound and the number of stations that can operate in a specific frequency range without interfering with each other.

In contrast, the physical size of the antenna, the strength of the signal, and the duration of the transmission pertain to different aspects of radio communication but do not define bandwidth. The antenna size affects the efficiency and capability of transmitting signals, signal strength relates to how well a signal can be received over distance, and transmission duration pertains to how long a signal is sent or broadcasted. Therefore, while all these elements are important in radio communications, 'bandwidth' specifically refers to the frequency range that is utilized for effective transmission.