Which factor could result in a high standing wave ratio on a transmission line?

A high standing wave ratio (SWR) on a transmission line often indicates an issue with how the impedance is matched along that line. A detuned antenna coupler can create impedance mismatches between the transmission line and the antenna it is intended to feed. When the antenna is not properly tuned to match the feed line’s characteristic impedance (usually 50 or 75 ohms for most RF applications), reflections occur. These reflections create standing waves along the transmission line, which lead to a high SWR reading.

In this context, having a detuned antenna coupler means that it is not effectively coupling power to the antenna, causing a portion of the signal to reflect back toward the transmitter. This reflection leads to an increase in the standing wave ratio, which can result in signal loss and potential damage to transmitting equipment if not addressed.

The other factors could impact the performance of a transmission line, but they are less directly related to the specific concept of standing wave ratio. Proper grounding is critical for overall system performance and safety, excessive cable length can contribute to attenuation and loss, and low impedance matching generally refers to the relationship between the transmitter and the line, but it is the detuned antenna coupler that directly leads to that significant reflection which manifests as a