ARRL Technician Practice Exam

Where should an in-line SWR meter be connected to monitor the standing wave ratio of the station antenna system?

1. Between the antenna and the ground

2. In series with the feed line, between the transmitter and antenna

3. Before the transmitter

4. After the ground system

The correct answer is: In series with the feed line, between the transmitter and antenna

To monitor the standing wave ratio (SWR) of a station antenna system effectively, the in-line SWR meter must be connected in series with the feed line, specifically between the transmitter and the antenna. This positioning allows the meter to accurately measure the ratio of reflected power to forward power as it travels along the feed line. When installed in this manner, the SWR meter can assess how much of the power transmitted by the station is actually radiated by the antenna versus how much is reflected back due to mismatches in impedance along the feed line. An ideal SWR is typically 1:1, meaning that all the transmitted power is being effectively radiated by the antenna, while a higher ratio indicates potential issues with the antenna system, such as poor matching or damage. The other choices do not facilitate accurate SWR measurement. Connecting the meter between the antenna and the ground would not capture the necessary data since it would not measure the signals traveling towards the antenna from the transmitter. Likewise, placing it before the transmitter or after the ground system would not allow the meter to measure the relationship between forward and reflected power in the feed line, which is essential for determining SWR.