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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.
AM and FM broadcast radio usually use vertical polarization, while television uses horizontal polarization. At low frequencies especially, horizontal polarization is avoided. That is because the phase of a horizontally polarized wave is reversed upon reflection by the ground. A distant station in the horizontal direction will receive both the ...
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
Vertically polarized outgoing radiation is important for long-distance transmissions in the mediumwaves and lower: The ground waves that carry radio signals at frequencies below about 2 MHz must be vertically polarized to reduce signal absorption by the Earth. [2]
Radio propagation is the behavior of radio waves as they travel, or are propagated, from one point to another in vacuum, or into various parts of the atmosphere. [1]: 26‑1 As a form of electromagnetic radiation, like light waves, radio waves are affected by the phenomena of reflection, refraction, diffraction, absorption, polarization, and scattering. [2]
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.
For example, a vertical dipole feed antenna will radiate a beam of radio waves with their electric field vertical, called vertical polarization. The receiving feed antenna must also have vertical polarization to receive them; if the feed is horizontal ( horizontal polarization ) the antenna will suffer a severe loss of gain.
The discone antenna has a useful frequency range of at least 10 to 1. [2] [3] When employed as a transmitting antenna, a properly constructed discone is just as efficient as an antenna designed for a more limited frequency range. The extra bandwidth comes from the controlled taper and large termination radius of the cone.