What is the term for a device that extends the effective range of communication by receiving and retransmitting radio signals?

The term for a device that extends the effective range of communication by receiving and retransmitting radio signals is a repeater. A repeater operates by receiving a radio signal and then retransmitting it, which helps to overcome obstacles like buildings and terrain that might otherwise weaken or block the signal. This process allows communication over longer distances or in areas where the original signal cannot reach effectively.

While transmitters, amplifiers, and receivers play important roles in communication systems, they do not have the same functionality as a repeater. A transmitter generates and sends signals, an amplifier boosts the power of signals to improve clarity and strength, and a receiver picks up signals for processing. None of these devices specifically perform the function of receiving and then retransmitting signals to increase communication range like a repeater does. Therefore, the correct term for the device described is indeed a repeater.