Stationary antennas. Types of base antennas.

A base (stationary) antenna is installed in a fixed position on a mast and operates from a single location, typically on a building or a permanent mast structure.

The primary purpose of a base antenna is to provide stable signal transmission over the maximum possible distance. For communication with moving objects, omnidirectional models are most suitable, while directional models are preferable for communication with fixed and stationary objects. In the VHF band, the most popular are base antennas with vertical polarization, as they are the easiest to install on vehicles. For television antennas, horizontal polarization is more common. For modern GSM 3G/4G modems, MIMO antennas with two orthogonal polarizations are used.

In VHF (134-174 MHz) and UHF (400-520 MHz) communications, the following types of base antennas are common:

GP (ground-plane) (quarter-wave vertical) – a rod of quarter-wavelength with three or more radials of the same length, positioned at a 40–45° downward angle, evenly distributed in all directions. This antenna type is the most common, easy to tune, and has an omnidirectional radiation pattern.

1/2 (half-wave) – a rod of half-wavelength, operating without radials, which simplifies installation. It is more efficient than the GP due to a more uniform radiation diagram but is less effective than the 5/8 type.

5/8 (five-eighths) – a rod of 5/8 wavelength with small radials (0.1–0.2 wavelength).

Yagi (YAGI or wave channel) – a directional antenna made of two or more elements, each about half a wavelength long. It offers a high gain factor.

Aperture antenna – a type of antenna that uses an open aperture for transmitting and receiving electromagnetic waves. It can have various shapes and designs, such as parabolic antennas, grid antennas, open waveguides, and others. Aperture antennas typically have a sharp beam pattern and can provide a narrow beam for signal transmission or reception. Aperture antennas are widely used in radio and microwave communication systems, radar, satellite communication systems, broadcasting, and other fields requiring the reception or transmission of electromagnetic signals. They can have different designs, including parabolic antennas, grid antennas, and open waveguides. Aperture antennas generally have high directional accuracy and can form narrow beams for signal transmission or reception. Advantages of aperture antennas include high efficiency, the ability to form narrow beams, high throughput capacity, and operation across various frequencies. However, they may also be more complex to design and manufacture compared to other antenna types, and may require more precise tuning and installation.

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