This tool converts Voltage Standing Wave Ratio or VSWR to Reflection Coefficient (sometimes referred to as Gamma) Γ.
Γ = (VSWR – 1)/(VSWR + 1)
VSWR is a positive number greater than or equal to 1
VSWR (sometimes called standing-wave ratio SWR) is a measure of the impedance match between a feedline’s characteristic impedance and the attached load. The load can be an antenna or any RF module such as a filter or amplifier. The greater the degree of mismatch the less efficient the design and implementation.
VSWR is often expressed as a ratio to 1. For example, if the VSWR is 1.9 then it is written as 1.9:1.
Within the context of antennas a good value of VSWR is 1.5 or lower. In an ideal situation, the load is perfectly matched to the feedline characteristic impedance, VSWR=1 and using the calculator Γ=0. In this case, no signal energy is reflected and all of it is transmitted forward.