The Picture Plane is the flat two-dimensional surface on which we draw or project an image in perspective. In the illustration above, it is a simple task to draw the two rectangles if they are parallel to the picture plane. The Ground Plane is at 90 degrees to the picture plane.
Then, what is a ground plane CB?
A ground plane for a CB radio antenna is the metal surface required below the antenna. In mobile applications, the vehicle body/frame acts as the ground plane (reflective unit). The metal surface enables the signal generated when transmitting to reflect off the surface and travel into the atmosphere.
Do you have to ground a CB antenna?
Ground Your Antenna Mount. If you're using a standard CB antenna (i.e., anything except a no ground plane, or NGP, kit), you'll need to make sure your antenna mount is solidly grounded to the vehicle's chassis. A bad ground will result in an un-tunable antenna and sky-high SWR levels.