Causes of Erratic SWR Changes in Amateur Radio

This question addresses the topic of Standing Wave Ratio (SWR) and its stability, which is crucial for efficient antenna system performance in amateur radio. SWR is a measure of the impedance matching of a load (i.e., the antenna) to the transmission line feeding it. Ideally, the impedance should be perfectly matched to ensure maximum power transfer and minimal signal loss. Significant erratic changes in SWR can indicate an underlying problem that may need to be addressed to maintain proper functioning of the radio system. The correct answer is that a loose connection in the antenna or feed line can cause erratic changes in SWR. This is because an intermittent or poor connection can alter the impedance characteristics of the system, causing fluctuations in the SWR readings. It’s important for ham radio operators to ensure that all connections are secure and stable to avoid such issues. Understanding and troubleshooting SWR irregularities is part of the foundational skills required for effective amateur radio operation, making this a highly relevant topic for the license exam.