VSWR is Voltage Standing Wave Ratio, this is the measurement of how well the antenna is matched to the signal you are trying to capture. The lower the ratio the better the match. Perfect would be 1:1. The image on the left is the VSWR for the 2.4GHz FCD Antenna Range. The Image in the center is a typical dipole antenna VSWR and as you can see it has a very narrow band width. The image on the right is the VSWR for the 915MHz FCD antenna.