How Do I Choose the Best Satellite Antenna?

The satellite antenna is often called a cauldron, which is a metal parabola, which is responsible for reflecting the satellite signal to the feed and tweeter located at the focal point. The function of the satellite antenna is to collect the weak signals from the satellite and remove noise as much as possible. Most antennas are usually parabolic, and some multifocal antennas are a combination of spherical and parabolic antennas. The satellite signal is reflected by the parabolic antenna and concentrated at its focal point.

Generally speaking, the larger the antenna diameter, the stronger the signal of the program and the higher the reception quality. However, considering the cost, installation and other factors, the user requires that the antenna diameter be as small as possible. Such as Asia 3S on C

Satellite antennas can be divided into two types: forward feed and offset feed.

Positive feedback is the cauldron we often say, receiving C-band programs.

Partial feed is also called small pot, which receives Ku programs.

C-band antennas have various specifications such as 1.35, 1.5, 1.8, 2.1, and 2.4M. In the Northeast, these specifications can fully meet the needs of receiving all domestic channels and internationally renowned channels such as Phoenix Satellite TV, CNN, BBC, and NHK. A number of important foreign resident agencies such as the US Consulate General in Shenyang and large star-rated hotels are also using Zhongwei antennas, and their quality has been affirmed by users. Ku antenna, commonly used specifications are 0.35, 0.45, 0.6, 0.75, 0.8, 0.9, 1.0, 1.2, 1.5M, etc., which can fully meet the needs of individuals in Northeast China, cable TV stations and "Village Village" projects. Different from the positive-feed antenna, the offset-feed antenna has an elliptical shape with a shallow surface radian, and the elevation angle is about 20 degrees lower than that of the positive-feed antenna when the front-loading method is used.

Center Focus Satellite Antenna

Center-focusing satellite antenna is generally called a positive focus antenna, also known as

The satellite TV receiving system is composed of a set of complete satellite receiving stations: a parabolic antenna, a feed source, a high frequency head, and a satellite receiver.

Parabolic antenna

The parabolic antenna reflects the satellite signal energy of the starry sky into a focal point.

Feed

The feed source is a horn with a satellite signal set at the focal point of the parabolic antenna. It is called a feed source, which means that the source of energy is required to collect all the energy that has been focused. Feedforward satellite receiving antenna is basically large

Installation and fixing

When installing a parabolic antenna, it is generally installed according to the structural diagram provided by the manufacturer. The antenna structures of all manufacturers are basically the same. Antenna structure There are two types of reflectors: integral forming and splitting (reflecting plates above 2M are basically splitting). There are two types of tripods: post feet and tripods (post feet are more common). The tripod is a horizontal tripod.

Here are the basic installation steps:

The horizontal tripod is installed on the prepared base, and the level is adjusted. Then, the tripod wire is solidified and welded. (The horizontal tripod must be adjusted to the azimuth angle before the tripod can be fixed.)

Attach the azimuth tray and the elevation adjustment screw.

Install the reflective plate's reinforcing bracket and the reflective plate on the reflective plate tray in order. When the reflective plate and the reflective plate are connected, they can be fixed for a while but not fastened. After all the components are installed, adjust the surface of the plate to be flat and then all the screws. Sturdy. It should be noted here that some manufacturers of split-reflective plates can be assembled randomly without any order, but some three-lobes have mounting points for the feed rods. These three-lobes must be installed in three points, otherwise the feed bracket is installed The reflection focus of the rear asymmetric feed and the antenna cannot overlap to affect the signal gain or even receive no signal. After the integrally formed reflecting plate is mounted on the tray rack, the reflecting plate can be directly mounted on the azimuth bracket.

Install the feed bracket and the feed fixing plate.

Installation and adjustment of the feed source and the high frequency head: The feed source and the high frequency head and the rectangular waveguide port connecting them must be aligned and aligned, and the inside of the waveguide port must be flat. Install the connected feed tweeter on the feed fixed plate, and focus on the center of the parabolic antenna.

Introduce a simple calculation method for calculating the focal length of the antenna:

According to the formula of the focal length ratio of the surface antenna: F / D 0.34 ~ 0.4. Now take 3M antenna as an example to calculate the focal length F = 3 × 0.35 + 0.15 = 1.2 (meters), where 0.15 is the correction value. The 3M antenna has a focal length of 1.2 meters.

Method for finding signal by satellite antenna

For general satellite enthusiasts,

Horn satellite antenna structure

Horn satellite antenna structure

The horn satellite antenna is the simplest of the antennas. Compared with a parabolic antenna, the area of the waveguide port of the horn antenna is small, so the gain and direction effects of the antenna are also small. If the horn antenna is used to receive satellite signals, its antenna gain is required to be at least 34 dB / ll.3 GHz. According to calculations, in order to achieve this gain, the required edge length of the horn antenna is 52 cm × 52 cm, and the structure length is 80 cm. Due to the high processing cost of horn antennas, it is obviously not practical to use horn satellite antennas to receive satellite signals, so people often use it for directional radio testing or as a feed system for reflective antennas. When a horn antenna is used as a feed for a reflective antenna, there are many types of structures, but most of them are circular, conical or conical.

Planar satellite antenna structure

Planar antennas are also known as flat panel antennas. The characteristics of flat antennas are good reception performance and small dimensions, which are especially suitable for home use. The structure of the planar antenna is very complicated, and the technical and accuracy requirements are also very high during production. The overall structure is a multilayer sandwich shape, which mainly includes two panels, two perforated sheets, a dielectric carrier film, and a reflective plate. The main part of the antenna is composed of many dipole antennas and a distribution network. During fabrication, several hundreds of t / 4 single dipoles are placed on the dielectric carrier film using an etching process. These single dipoles have a regular transverse shape and gap shape in the diaphragm. Thereafter, a dielectric carrier film is placed between two porous sheets. During the production, the precision between the plate and the plate is very precise. Finally, the reflector is placed behind the diaphragm at an A / 4 pitch, and the control of each single dipole antenna by the flat plate antenna is realized by a distribution network. In this distribution network, the amplitude and phase of the signal are accurately gathered. This is very important for flat antennas.

Main focusing satellite reflecting surface antenna structure

A typical reflector antenna consists of a feed horn and a rotating paraboloid. The feed source is placed in the focal point of the metal reflecting surface, and the focused high-frequency energy is fed into the receiving device through the waveguide. The characteristics of this antenna are: it can be made into any size according to the needs of the frequency range. In general, the quality of the reflecting surface and the accuracy of the iso-field strength line can affect the antenna gain and efficiency. In particular, the accuracy of the iso-field strength line does not allow any deviation, otherwise it will cause the focus to move. For the receiving antenna, the focus shift means that the high-frequency energy reflected by the main reflecting surface cannot all reach the feed system. After high-frequency energy is lost, antenna efficiency and gain deteriorate. When the reflector antenna diameter is 55 cm, the antenna gain can reach 34dB. ^[7]