Here are some of the most common antennas used for repeater stations:
Yagi antenna: Yagi antennas are directional antennas that are very efficient at receiving and transmitting radio signals. They are typically made up of a series of parallel elements that are arranged in a line. The number of elements in a Yagi antenna determines its gain, with more elements providing more gain. Yagi antennas are often used for repeater stations because they can provide a high degree of signal amplification, which can extend the range of the repeater.
Log-periodic antenna: Log-periodic antennas are also directional antennas that are very efficient at receiving and transmitting radio signals. They are typically made up of a series of parallel elements that are arranged in a logarithmic spiral pattern. The number of elements in a log-periodic antenna determines its frequency range, with more elements providing a wider frequency range. Log-periodic antennas are often used for repeater stations because they can provide a high degree of signal amplification over a wide frequency range.
Sector antenna: Sector antennas are directional antennas that are designed to transmit a signal in a specific direction. They are typically used for repeater stations that need to cover a wide area in a particular direction, such as a highway or a river. Sector antennas are available in a variety of gains and beamwidths, so they can be tailored to the specific needs of the repeater station.
Omni directional antenna: Omnidirectional antennas are antennas that transmit and receive radio signals in all directions. They are often used for repeater stations that need to cover a wide area in all directions, such as a city or a park. Omnidirectional antennas are not as efficient as directional antennas, but they are much simpler to install and maintain.
In addition to these four types of antennas, there are also a number of other antennas that can be used for repeater stations, such as discone antennas, helical antennas, and parabolic antennas. The best antenna for a particular repeater station will depend on the specific needs of the station.