If a transmission line shows a VSWR of 30:1, what does it indicate?

A Voltage Standing Wave Ratio (VSWR) of 30:1 indicates a significant mismatch between the transmission line and the load it is connected to. This high ratio suggests that there is a large amount of reflected power due to either an open or short circuit condition in the cable.

When the VSWR is very high, it implies that most of the power sent along the transmission line is being reflected back rather than being transmitted to the load as intended. This reflection occurs because either the load does not present the appropriate impedance (resulting in an open circuit) or connects to a conductor that is unintentionally creating a complete circuit back to the source (resulting in a short).

In contrast, a low VSWR value would suggest that the transmission line is functioning properly and that there is a good impedance match, allowing for efficient power transfer. A perfectly matched line would have a VSWR of 1:1, while signal amplification is unrelated to the VSWR value and typically involves active circuitry rather than impedance issues. Thus, the indication of a high VSWR of 30:1 strongly correlates with open or shorted line conditions.