I use a KD9SV pre-amp for my reversible beverage on the ground (RBOG) available from DX Engineering (DXE Part number: SVP-SV-PP160RBOG). It is not a kit. Pre-amp works very well, is low noise and has 20db of gain As for height, the experts say laying on the ground or a couple of inches. I am not an expert here. My RBOG is on the ground 73, Ed N4OC