VSWR and return loss converter
Linked conversion between VSWR, return loss (RL) and reflection coefficient (Γ), with reflected power and mismatch loss.
Formulas
|Γ| = (VSWR − 1) / (VSWR + 1)
VSWR = (1 + |Γ|) / (1 − |Γ|)
RL = −20·log₁₀(|Γ|) (dB)
Reflected power = |Γ|² × 100%
Engineering background
VSWR measures transmission-line to load impedance match; 1.0:1 is ideal. Larger return loss means better match. Reflection coefficient |Γ| ranges 0 (perfect match) to 1 (full reflection).
Key benefits
Enter any of VSWR, return loss or reflection coefficient and instantly get the other two plus reflected power and mismatch loss.
Built-in match-quality verdict (perfect/excellent/good/poor) for at-a-glance antenna status.
Suited to antenna tuning, feedline matching and power-amplifier load assessment.
How to use
- 1 Enter a value in the VSWR, RL or |Γ| field.
- 2 The other metrics update in real time.
- 3 Review the match quality and reflected-power percentage.
Use cases
- › Antenna VSWR tuning: check whether VSWR meets the typical ≤ 1.5 requirement.
- › Feedline matching: judge feedline-to-antenna connection quality from return loss.
- › PA load protection: estimate before a high-VSWR protection circuit trips.
FAQ
How much power reflects at VSWR 1.5?
|Γ| = 0.2, so reflected power = 0.2² = 4%.
Why is return loss shown as a positive number?
By convention this tool outputs positive dB (e.g. RL = 20 dB means 20 dB of reflection attenuation); some literature uses the negative form for the same concept.
At what VSWR is a mismatch considered severe?
Typically VSWR > 3 is severe, with over 25% reflected power and potential PA damage.