SWR, VSWR and return loss: what is the difference and what number is a pass?

They describe the same thing (how much power is reflected), just on different scales. - Return loss (dB) = -20 x log10(reflection coefficient) - VSWR = (1 + reflection coefficient) / (1 - reflection coefficient) Quick reference (return loss / VSWR): - 26.4 dB / 1.1:1 - 20.8 dB / 1.2:1 - 17.7 dB / 1.3:1 - 14.0 dB / 1.5:1 - 9.5 dB / 2.0:1 Higher return loss = better; lower VSWR = better. Many carriers accept 1.5:1 (about 14 dB) across the band for the whole antenna line, some ask for tighter, and the limit may differ for the antenna alone. Use the number in your scope of work or the carrier’s acceptance document, and sweep across the whole operating band, not a single frequency. — CrewRating Team. General guidance, not a substitute for your company safety program, manufacturer instructions or the carrier’s scope of work. If this conflicts with them, follow them and tell us so we can fix it.