ARRL Technician Practice Exam 2025 – Complete Prep Guide

The primary function of an antenna tuner is to match the impedance of the antenna system to the transceiver's output impedance. This is essential because an unmatched impedance can result in significant signal loss and reduced efficiency in transmission. A typical transceiver output impedance is 50 ohms, and many antennas may not have this same impedance. Through the use of an antenna tuner, the antenna system can be adjusted so that it presents a correct load to the transmitter. This matching process minimizes standing waves and ensures that more of the transmit power is successfully radiated rather than reflected back, which can lead to damage to the transmitter.

In this context, while amplification of signal strength might be an important objective in some scenarios, it is not the primary role of an antenna tuner. Similarly, changing the frequency or converting RF signals to AF signals are functions associated with other equipment in a radio setup, rather than the specific role of an antenna tuner.