I made a reflector for a little 2dBi whip which increased signal strength by 5-10%. Made it from half cut tin can and experimenting with distance and angle. I did this simply on the assumption that the wave pattern for the whip would be doughnut shaped and that the semicircle of metal would reflect back lost signal and make the antenna more directional.
Question, am I theorizing correctly on this and is there any way to make an even better reflector than the one I made?