What does an SWR reading of 4:1 indicate?

• A. Perfect match
• B. Low efficiency
• C. High gain
• D. Impedance mismatch

Answer: (D)

An SWR (Standing Wave Ratio) reading of 4:1 indicates an impedance mismatch between the transmitter, antenna, and transmission line. An ideal SWR reading is 1:1, meaning that the impedance of the antenna matches the impedance of the transmission line and the transmitter, allowing maximum power transfer. When the SWR rises to 4:1, it suggests that there is a significant mismatch, leading to some of the transmitted power being reflected back instead of being radiated by the antenna.

This mismatch can cause inefficiencies in the system, as reflected power not only reduces the effective power radiated, but it can also potentially damage the transmitter if the reflected power is high enough. Therefore, a high SWR reading indicates the need for adjustment or troubleshooting in the antenna system to improve performance and efficiency.