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The vertical plane is used 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.
The electric field or "E" plane determines the polarization or orientation of the radio wave. For a vertically polarized antenna, the E-plane usually coincides with the vertical/elevation plane. For a horizontally polarized antenna, the E-Plane usually coincides with the horizontal/azimuth plane. E- plane and H-plane should be 90 degrees apart.
But a vertical "whip antenna" or AM broadcast tower used as an antenna element (again, for observers horizontally displaced from it) will transmit in the vertical polarization. A turnstile antenna with its four arms in the horizontal plane, likewise transmits horizontally polarized radiation toward the horizon. However, when that same turnstile ...
For instance, an antenna composed of a linear conductor (such as a dipole or whip antenna) oriented vertically will result in vertical polarization; if turned on its side the same antenna's polarization will be horizontal. Reflections generally affect polarization. Radio waves reflected off the ionosphere can change the wave's polarization.
Vertical polarized VHF-UHF biconical antenna 170–1100 MHz with omnidirectional H-plane pattern. Omnidirectional radiation patterns are produced by the simplest practical antennas, monopole and dipole antennas, consisting of one or two straight rod conductors on a common axis.
Unlike a dipole antenna, the polarization of a resonant loop antenna is not obvious from the orientation of the loop itself, but depends on the placement of its feedpoint. [e] If a vertically oriented loop is fed at the bottom, then its radiation will be horizontally polarized; feeding it from the side will make it vertically polarized.
A vertical whip radiates vertically polarized radio waves, with the electric field vertical and the magnetic field horizontal. Vertical whip antennas are widely used for nondirectional radio communication on the surface of the Earth, where the direction to the transmitter (or the receiver) is unknown or constantly changing, for example in ...
The horizontal gain continues to increase up to a maximum of about 6.6 dBi at a length of five-eighths wavelength 5 / 8 λ so this is a popular length for ground wave antennas and terrestrial communication antennas, for frequencies where a larger antenna size is feasible. The input impedance drops to about 40 Ohms at that length.