Ham Radio Extra Class Practice Test 2025 - Free Extra Class License Exam Questions and Study Guide

A wattmeter is specifically designed to measure the power output of a transmitter. It provides a direct measurement of the electrical power being delivered to the antenna, which is typically expressed in watts. This is crucial for ensuring that the transmitter operates within legal power limits and for optimizing performance.

The device works by measuring both the voltage and current flowing through the transmission line and calculating the product to determine power output. This ensures that operators can verify their transmitter's performance and make necessary adjustments.

While a multimeter can measure voltage and current, it cannot directly provide power output without further calculations. A frequency counter is used to measure the frequency of a signal, and an oscilloscope is used to visualize waveforms, but neither provides a direct measurement of power output. Thus, the wattmeter is the most appropriate tool for this purpose.