What does an SWR reading of less than 1.5:1 mean?

SWR (Standing Wave Ratio) measures how well the antenna and transmission line impedances match the transmitter. A perfect match is represented by a 1:1 ratio. Anything under 1.5:1 indicates a very efficient transfer of power from the transmitter to the antenna, meaning it is a fairly good impedance match. High readings, such as 3:1 or above, indicate a significant mismatch where power is being reflected back to the transmitter. Options suggesting an impedance match that is 'too low' or related to 'antenna gain' are incorrect distractors, as SWR does not measure signal gain, but rather how closely the system aligns with a standard 50-ohm impedance.