Garmin G900X Installation And Maintenance Manual page 471

C.2.5.4 COM Antenna VSWR Checks
Check for insertion loss and VSWR (Voltage Standing Wave Ratio). VSWR should be checked with an
in-line type VSWR/wattmeter inserted in the coaxial transmission line between the transceiver and the
antenna. The VSWR should be inserted as close to the transceiver as possible. Any problem with the
antenna installation is most likely seen as high reflected power. A VSWR of 3:1 may result in up to a
50% loss in transmit power. Ideally, the VSWR should be 2.5:1 or less.
G900X/G950 Installation and Maintenance Manual – PICP & Warranty Registration Page C-27
190-00719-00 Revision D