Vertical plane is used in radio to plot an antenna's relative field strength perpendicular to the ground (which directly affects a station's coverage area) on a polar graph.
Normally the maximum of 1.000 or 0 dB is at the side (unless there is beam tilt), which is labeled 0°, to 90° at the top and −90° at the bottom. Other field strengths are expressed as a decimal less than 1.000, a percentage less than 100%, or decibels less than 0 dB.
Most broadcast antennas use either line-of-sight or ground wave propagation (a slight refraction towards the ground) to reach their nearby listeners, and thus want a low angle in the vertical plane. Short wave transmitters want a somewhat higher elevation angle in the vertical plane to encourage skywave propagation, which would refract or reflect radio waves off the ionosphere and back to the ground at a great distance from the transmitter.
Omni directional antennas typically try to limit the range of their vertical plane radiation pattern to concentrate energy over a smaller range and increase gain.
Famous quotes containing the words vertical and/or plane:
“I tell you, hopeless grief is passionless;
That only men incredulous of despair,
Half-taught in anguish, through the midnight air
Beat upward to God’s throne in loud access
Of shrieking and reproach. Full desertness,
In souls as countries, lieth silent-bare
Under the blanching, vertical eye-glare
Of the absolute Heavens.”
—Elizabeth Barrett Browning (1806–1861)
“At the moment when a man openly makes known his difference of opinion from a well-known party leader, the whole world thinks that he must be angry with the latter. Sometimes, however, he is just on the point of ceasing to be angry with him. He ventures to put himself on the same plane as his opponent, and is free from the tortures of suppressed envy.”
—Friedrich Nietzsche (1844–1900)