Here I show how I made an octahedral radar reflect from 18 gauge aluminum sheet, JB Weld, and edge trim. I will fasten this to the mast of my Cape Dory 25D sailboat. RADAR (radio detection and ranging) sends out a signal and listens for an echo in order to plot the range and bearing of anything solid, like land or other vessels. A radar reflector, such as the one I build in this video, when attached to a high-point on an object such as a small boat like mine, is good at returning the radar signals and helps other boats "see" me. This is especially useful during times of diminished visibility (e.g., fog, storms, night).