At a named reference plane, reflection coefficient Γ is the reflected-to-incident voltage-wave ratio. Return loss is -20 log10|Γ|, VSWR is (1+|Γ|)/(1-|Γ|), reflected power fraction is |Γ|² and mismatch loss is -10 log10(1-|Γ|²). All values must refer to the same plane and impedance.
For 1.5:1 VSWR, |Γ| is 0.2, return loss is about 14.0 dB and approximately 4% of incident power is reflected. This does not describe connector loss, absorber heating, pulse capability or uncertainty, and it should not be treated as a complete load rating.
Measure over the full required band and include adapters or fixtures only when the specification includes them. Preserve complex reflection data so reference-plane shifts, resonances and comparisons can be investigated later.