Which instrument can be used to determine SWR?

To determine the Standing Wave Ratio (SWR) of an antenna system, you need to measure both the forward power traveling to the antenna and the reflected power bouncing back toward the transmitter. A directional wattmeter is designed specifically to measure RF power flowing in a specific direction, allowing you to compare the forward and reflected power to easily calculate the SWR. Standard voltmeters and ohmmeters measure basic electrical properties at DC or very low frequencies and cannot be used to measure high-frequency RF power flow on a transmission line. An "iambic pentameter" is a humorous distractor, as it refers to a rhythmic meter used in poetry, not an electronic testing instrument!