In recent years, worldwide trends in the increasing interest of the population in satellite television have been observed, and as a result of its rapid development – constantly launched new satellites, “open” and “closed” channels.
In the price aspect, satellite TV is more expensive, but the money invested justifies itself at the expense of a large selection of channels, excellent image quality and sound.
The construction of satellite television systems is based on the principle of retransmission of signals from the spacecraft (satellite) from transmitting ground stations to end-users receivers (viewers). One satellite can cover up to one third of the earth’s surface area.
The result of the improvement of satellite television has become the popularization of satellite TV systems. Owners of hotels and resorts no longer need to install satellite dishes separately in each room, and developers of apartment complexes worry about damaged facades of buildings through numerous satellite “dishes” that look out of almost every window.
The standard system includes collective satellite antenna port (or antenna post) kanaloutvoryuvalnoho equipment, distribution network and receiving equipment end users.
Antenna port (antenna post) is a complex of satellite antennas that provide reception of signals from satellites.
With the help of channel-forming equipment (HeadEnd Station, multiswiches, ..), TV signals arriving from the antenna port are transformed and subsequently transmitted to distribution networks of television, the main task of which is to deliver a group signal of a certain level to each subscriber TV receiver with a minimum distortion and noise and with the same level of signal at any point in the network. The professionally built antenna port undoubtedly plays a key role in this scheme.
The construction of the antenna port begins with measurements at the intended location of the antennas to detect obstacles from the existing communication lines and determine the required antenna diameters.
To select equipment for satellite reception, it is also necessary to analyze TV programs that are planned to be broadcast. The satellites from which these programs are broadcast, the frequency and polarization of the packages in which they are located are determined.
The receiving satellite antenna is intended for reception and concentration of electromagnetic waves from a satellite-repeater. Today, the most widely used offset wide-band satellite dish. It has a shifted focus, an oval shape of the reflector, and also makes it possible to install an additional converter (a device that collects a focused antenna signal) for receiving signals to 3 satellites.
The material from which the antenna is made is largely determined by its characteristics and the warranty period for its operation. At present, antennas are made of steel, aluminum and thermoplastics. Nowadays, the most popular thermoplastic casting antennas, which guarantee the stability of the electrical characteristics of the antenna for 10-15 years.
The electrical characteristics of the antenna are influenced by the deviation of the shape of the surface of the antenna mirror, which may be the result of poor-quality production or the consequence of an improperly designed accommodation project. For example, for an individual satellite antenna, the deviation of the surface shape by 2 mm leads to a 10% decrease in the gain.
The world’s leading satellite antennas for antenna ports are SkyWare Global, ASC Signal, VERTEX, Prodelin, Mabo, Supral.
One of the most important elements of the antenna is its mounting device – a supporting and rotary device that is designed to suspend the satellite antenna, directing its beam to the satellite-repeater and reliable mechanical fixation of the antenna orientation. The main factors affecting the destabilization of the receiving antenna orientation are wind loads (especially the lateral wind), aging (effects associated with shrinkage of the reflector and the bearing platform) and mechanical vibrations.
An antenna can be not only oriented on one satellite, but also re-targeted on a special rotary device from the satellite to the satellite. The support-turning devices are classified according to the pattern of the suspension of the mirror.
Polar pendants have won the most popularity, which make it possible to have a breadth of view up to 2000 azimuth, that is, it is possible to receive a signal from any satellite that is not shadowed by the Earth. APEXSAT is the most recognized leader in this field. The rotation of the antenna around the polar axis is provided by the electric drive. The most reliable engines for satellite dishes are manufactured by Patriot, Thomson Saginaw.
Depending on the location of the installation (roof of the building, wall, ground area), the diameter of the antennas and their masses, it is necessary to use the corresponding designs of the mounting device on which the antennas are mounted. The calculation of the design must be made on the basis of the conditions for ensuring the required reliability in the wind and ice loading. In addition to ensuring that the structure of the support is non-destructive, it is also necessary, even at maximum winds, to keep the antenna deviations from the axis in accordance with the specified parameters (for a satellite dish 1,8 m in diameter there should be no more than 0,70).
Systems of anti-icing of satellite antennas SHS are considered to be one of the most effective.
In the standard scheme used welded metal structures for mounting antennas, representing grids from the channels. For the reliability of the mounting of the support and the stability of the structure, concrete reinforced concrete supports are reinforced with a metal rod. It is important to know that only the correct calculation of the design will help to avoid the effects of vibrations that are created due to wind load (resonance effect) and can lead to deformation and destruction of the entire building. All antenna ports must also be equipped with a lightning protection system.
Given the foregoing, there is no doubt that the professionally designed and implemented project of the antenna port is a guarantee of success in the construction of the entire satellite system
Group of channels “1+1”