What is the function of an SWR meter?

The function of an SWR meter is to measure the standing wave ratio. This critical measurement indicates how efficiently radio frequency (RF) power is being transmitted from the transmitter through the feed line to the antenna. An ideal situation occurs when all the power is radiated by the antenna. However, if some of the power is reflected back towards the transmitter due to mismatched impedance between the antenna and the transmission line, the SWR meter will provide a reading that highlights this inefficiency.

A high standing wave ratio indicates that a significant portion of the transmitted power is not being radiated and is instead being reflected back. This can lead to potential damage to the transmitter over time and is therefore important for radio operators to monitor. By maintaining an optimal SWR, operators can ensure better performance and longevity of their equipment.

The other choices do not directly relate to the primary function of an SWR meter. While frequency and power output are important measurements in ham radio operations, they are not the specific function of an SWR meter. Improving signal modulation, meanwhile, is more about the quality of the transmission itself rather than the efficiency of power transmission measured by the SWR meter.