The Basic lessons · Feedlines and antenna systems · B-006-005

Understanding SWR and Impedance Matching

Learn why matching your antenna to the feedline matters and how to read Standing Wave Ratio (SWR) meters. Discover what causes high SWR, why it increases signal loss, and how to use an antenna analyzer to fix problems.

This lesson is part of SignalPrep Pro. The subsection's 11 exam questions are free to practise: practise B-006-005.

What this subsection asks

• What does an SWR reading of 1:1 mean?
• What does an SWR reading of less than 1.5:1 mean?
• What is the most likely cause of erratic readings on an SWR meter?
• Which of the following can cause a high SWR reading?
• What is the main adverse effect due to operating with high SWR?
• What instrument is useful in adjusting the physical length of an antenna?
• If the characteristic impedance of the transmission line does not match the antenna input impedance then:
• The result of the presence of standing waves on a transmission line is:
• What does an SWR meter measure to determine the SWR?
• What information can be obtained with an antenna analyzer?
• What is the effect of line loss on the SWR reading at the station?