What device is used to extend the range of radio communications?

A repeater is used to extend the range of radio communications by receiving a radio signal and retransmitting it at a higher power or to a different frequency. This process effectively increases the distance over which the original signal can be transmitted and received. In practical terms, when a signal encounters obstacles or distance-related attenuation, a repeater ensures that the communication can continue seamlessly by boosting the strength of the signal.

Transmitters and receivers serve different purposes in the communication process; transmitters generate the signal while receivers capture it. An amplifier, on the other hand, enhances the strength of an existing signal but does not retransmit it as a repeater does. Therefore, the functionality of a repeater is specifically designed to address the needs of extending communication range, making it the correct choice.