Vertical plane is used in radio to plot a antenna's relative field strength (which directly affects a station's coverage area) on a polar graph.

Normally the maximum of 1.000 or 0dB is at the side (unless there is beam tilt), which is labeled 0o, to 90o at the top and -90o at the bottom. Other field strengths are expressed as a decimal less than 1.000, a percentage less than 100%, or decibels less than 0dB.

See also the perpendicular horizontal plane.