ARRL Technician Practice Exam

What reading on an SWR meter indicates a perfect impedance match between the antenna and the feed line?

1. 2 to 1

2. 1 to 1

3. 3 to 1

4. 4 to 1

The correct answer is: 1 to 1

A reading of 1 to 1 on an SWR (Standing Wave Ratio) meter indicates a perfect impedance match between the antenna and the feed line. In radio communication, achieving a 1:1 SWR means that the impedance of the antenna is exactly matched to the impedance of the transmission line (typically 50 or 75 ohms). This optimal matching ensures minimal signal reflection, maximizing power transfer from the transmitter to the antenna. Higher SWR values, such as 2 to 1, 3 to 1, or 4 to 1, indicate increasing levels of mismatch between the antenna and the feed line. As the SWR rises, the amount of reflected power increases, which can lead to signal losses and potentially damage to the transmitter if the SWR is significantly high. Therefore, a 1:1 reading is ideal for efficient operation and performance in radio communication.