Vertical plane
Encyclopedia
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 decibel
s 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
.
Field strength
In physics, the field strength of a field is the magnitude of its vector value.In theoretical physics, field strength is another name for the curvature form...
perpendicular to the ground (which directly affects a station's coverage area) on a polar graph
Polar coordinate system
In mathematics, the polar coordinate system is a two-dimensional coordinate system in which each point on a plane is determined by a distance from a fixed point and an angle from a fixed direction....
.
Normally the maximum of 1.000 or 0 dB
Decibel
The decibel is a logarithmic unit that indicates the ratio of a physical quantity relative to a specified or implied reference level. A ratio in decibels is ten times the logarithm to base 10 of the ratio of two power quantities...
is at the side (unless there is beam tilt
Beam tilt
Beam tilt is used in radio to aim the main lobe of the vertical plane radiation pattern of an antenna below the horizontal plane.The simplest way is mechanical beam tilt, where the antenna is physically mounted in such a manner as to lower the angle of the signal on one side...
), 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 decibel
Decibel
The decibel is a logarithmic unit that indicates the ratio of a physical quantity relative to a specified or implied reference level. A ratio in decibels is ten times the logarithm to base 10 of the ratio of two power quantities...
s less than 0 dB.
Most broadcast antennas use either line-of-sight
Line-of-sight propagation
Line-of-sight propagation refers to electro-magnetic radiation or acoustic wave propagation. Electromagnetic transmission includes light emissions traveling in a straight line...
or ground wave
Surface wave
In physics, a surface wave is a mechanical wave that propagates along the interface between differing media, usually two fluids with different densities. A surface wave can also be an electromagnetic wave guided by a refractive index gradient...
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
Skywave
Skywave is the propagation of electromagnetic waves bent back to the Earth's surface by the ionosphere. As a result of skywave propagation, a broadcast signal from a distant AM broadcasting station at night, or from a shortwave radio station can sometimes be heard as clearly as local...
propagation, which would refract or reflect radio waves off the ionosphere
Ionosphere
The ionosphere is a part of the upper atmosphere, comprising portions of the mesosphere, thermosphere and exosphere, distinguished because it is ionized by solar radiation. It plays an important part in atmospheric electricity and forms the inner edge of the magnetosphere...
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
Antenna gain
In electromagnetics, an antenna's power gain or simply gain is a key performance figure which combines the antenna's directivity and electrical efficiency. As a transmitting antenna, the figure describes how well the antenna converts input power into radio waves headed in a specified direction...
.
See also
- the horizontal planeHorizontal planeIn geometry, physics, astronomy, geography, and related sciences, a plane is said to be horizontal at a given point if it is perpendicular to the gradient of the gravity field at that point— in other words, if apparent gravity makes a plumb bob hang perpendicular to the plane at that point.In...
, perpendicular to the vertical plane - Radio propagationRadio propagationRadio propagation is the behavior of radio waves when they are transmitted, or propagated from one point on the Earth to another, or into various parts of the atmosphere...