“In this Instructable I’ll show you how I built a low-cost antenna analyser which can measure an antenna and display its VSWR over any or all of the HF frequency bands. It will find the minimum VSWR and corresponding frequency for each band but also will display a realtime VSWR for a user-selected frequency to facilitate antenna adjustment. It also has a USB port on the back for outputting frequency and VSWR data, to allow graph-plotting on a PC. The USB port can also be used to reflash the firmware if needed.”