A device that receives a transmission from a low-power source on one frequency and retransmits it at a higher power on another frequency is a/an?

• A. Mobile transmitter
• B. Encoder
• C. Repeater
• D. Decoder

Answer: (C)

In radio systems, the function described is a repeater. A repeater listens for a weak transmission on one frequency, then boosts the signal and transmits it on a second (often different) frequency at higher power. This relays the message to units that are farther away or on the far side of obstacles, effectively extending coverage and improving reliability for field communications. In EMS contexts, repeaters help connect field units with dispatch and bases, especially inside buildings or across varying terrain by providing a stronger, clearer link.

Encoding and decoding change the data format or interpretation, not the power or the relaying of the signal. A mobile transmitter simply sends a signal without the relaying function that a repeater provides.