Huge satellite dishes. How does a satellite dish work

Before choosing a satellite dish (dish), you need to get an idea of ​​how it works. In principle, the operation of the cymbal is not difficult. The antenna itself, the dish in our understanding, is a reflector electromagnetic waves, similar to a conventional mirror, which she focuses on a converter rigidly mounted on a plate. The converter converts the signal received from the satellite into the first intermediate frequency and transmits it to the receiver via the cable. The set, consisting of a reflector, a converter, is the receiving antenna itself.
Antennas by their design are divided into two main types - direct focus (round) and offset (elliptical).
Satellite signals are broadcasted mainly in the Ku bands (~ 11 GHz) and less often in C (~ 4 GHz), that is, the signals have a wavelength of 27 and 75 mm, respectively.
Everything Russian operators satellite TV: NTV plus, Tricolor TV, Continent TV, Rainbow TV, etc. work in the Ku (~ 11 GHz) band!

Satellite dish parameters

Effective area antennas A(effective surface of the antenna) - a value that characterizes the ability of the receiving antenna to concentrate incident on it electromagnetic radiation. A is defined as a relation maximum power, which can be given by the receiving antenna (without losses) to the matched load, to the power P, plane wave (not distorted by the antenna) per unit area of ​​the antenna.

Antenna noise temperature... Noises increase the response threshold digital devices from the useful signal. The antennas themselves do not make noise, noise is created by the surface of the earth, structures on it, ether, far and near space. Obviously, for given dimensions antennas, the noise will be less for antennas with a narrow radiation pattern and small side lobes.

The receiving and transmitting antennas use the same principle of operation, since in almost any linear systems the conversion factors of the fields are mutual. However, the technical and operational features of the receiving and transmitting antennas can differ significantly due to the difference in the requirements imposed on them (maximum power, frequency band, noise, etc.).

Selecting a satellite dish

How to choose an antenna by size. When choosing an antenna, a very important parameter is its the size. Size is directly related to the gain of the cymbal; the larger the size, the higher the gain. If the size of the dish is less than the one allowed for receiving the required transponder, then on the TV screen the message "no signal" will appear, if we have a threshold signal level, then the image will crumble into squares, the same will happen if the dish is inaccurately tuned to the satellite and when shielding satellite signal foreign objects.
For different capacities satellite signals require different diameters of plates: 53dbW - 0.6m, 48dbW - 0.8m, 45dbW - 1.0m, 40dbW - 1.5m.
Usually, installers know what size of dish it is possible to "catch" the desired satellite, how to determine it yourself right size we will tell you about the plates at the end of the article.

How to choose an antenna by type. Next, you need to decide on the type of antenna: direct focus (round) or offset (elliptical)?
Up to 1.6m, for domestic needs in the Ku (~ 11 GHz) band, offset antennas are mainly used, why?

It follows from the figure that the converter and the fixtures for its attachment create a radio shade on the dish, this reduces the efficiency of signal reception. In addition, during precipitation, water accumulates in the dish, especially at a high elevation angle, closer to the equator, as well as snow, which also reduces the efficiency of satellite signal reception.
Already for satellite dishes of 1.5 m or more, the radio shade from the converter and its fasteners makes up a relatively small part of the mirror area in order to take it into account. A round direct focus antenna more uniformly focuses radio waves on the converter feed. In addition, for a circular antenna it is easier to calculate and match the feed of the converter with the antenna, thanks to which the entire surface of the antenna is effectively used. On the other hand, for an offset plate, up to about 10% of the area is not used due to its shape, especially for large plates.
For these reasons, antennas larger than 1.5m are mainly manufactured as direct focus antennas and are intended for professional reception.

An offset antenna - with a shifted focus, has the shape of an ellipse, elongated vertically. The converter is mounted on a special bracket, due to the shifted focus of the antenna, the converter and its attachment point do not fall into the irradiation zone. The reception efficiency of such an antenna is higher than that of a direct focus one. The plane of such antennas is located almost perpendicular to the plane of the earth and precipitation on its surface does not accumulate. The design of mounting an offset antenna is simpler than that of a round antenna and its cost is lower. Choosing an offset antenna!

How to choose an antenna by design, material and stamping quality. Antennas differ in constructions- solid (solid-stamped), mesh and prefabricated (sectional). Solid antennas are preferred as they provide better reception. Mesh plates, for example Lance, have a reduced windage, but the efficiency of their reception is lower than that of solid ones. Some people believe that the holes in the grid themselves reduce the efficiency of the antenna, so that the signal "leaks" through them. In fact, the holes have nothing to do with it. The fact is that the mesh is soft and in the intervals between the stiffening elements of the plate it stretches, tending to take a flat shape, as a result of which the surface of the mesh plate is not a paraboloid, but consists of flat segments that form a surface close to a paraboloid. An antenna paraboloid is considered flat if the average dimensions of the irregularities on the surface of the dish do not exceed one quarter of the wavelength. In the Ku range, the length is 2.5 cm, while the permissible deviation of the surface from the paraboloid is approximately 6 mm. In the C range, the wavelength is 7.5 cm, and the dimensions of the irregularities can therefore reach 19 mm. Because of this, in the C-band, to lighten the weight, the antennas are made mesh, and to reduce the dimensions during transportation, they are made of petals, because C-band antennas are usually over 1.6m in size.
Material, from which the antenna mirror is made, can also be different: plastic, due to Bad quality antennas, due to warping in the sun, are practically not used, steel is a durable material, therefore it provides good quality mirrors, but the plates are heavy and prone to corrosion, aluminum is a light but soft material, subject to deformation and does not rust.
Stamping quality, is directly related to the antenna gain. The quality is easy to check by placing the antenna on thick glass; with good quality, the plate will fit snugly against the glass around its entire circumference. Particularly bad for the antenna gain is its warpage by the "screw".

How to choose an antenna by the type of suspension. Distinguish antennas with azimuth and polar suspension... With an azimuth suspension, the antenna is tuned to the satellite and rigidly fixed to the bracket. Polar - a suspension rotating by a special actuator. With the help of the polar gimbal, you can tune to all satellites "visible" in the given geographic coordinates.
The polar suspension is made in such a way that, turning around the vertical axis (i.e. changing the azimuth of the tuning to the satellites), the antenna also tracks the elevation angle, that is, it seems to describe the arc on which the satellites are located.
For household antennas, polar suspensions are now not relevant, they have been replaced by motorized suspensions, they are hung on conventional antennas with azimuth suspension.

Mirrors of various depths: 1 - shallow (long-focus); 2- average in depth (mid-focus); 3 - deep (short throw)

The directional pattern of a parabolic antenna is completely determined by the field distribution in its aperture, as well as the ratio between the wavelength and the radius of the mirror aperture.
At a certain value of the antenna aperture of the mirror, the main lobe of the radiation pattern will be the narrowest if the distribution of the field amplitude in the mirror aperture is uniform, but in this case the side lobes will also be large. If the amplitude of the field decreases from the center to the edges of the mirror, then the main lobe of the radiation pattern becomes wider and the levels of the side lobes decrease.
To reduce the level of side lobes, the antenna mirror is irradiated in such a way that the field amplitude decreases when moving from the center of the aperture to its edges, but the utilization factor of the aperture surface also decreases. In practice, a compromise solution is sought for rational irradiation of the mirror.
If one strives to obtain the highest gain from a parobolic antenna, then the mirror is irradiated in such a way that the field amplitude at its edges is 10 dB lower than in the center of the aperture.
If one wants to reduce the side lobes and thereby reduce the noise temperature of the antenna, then the mirror is irradiated in such a way that the field amplitude at its edges is 15–20 dB lower than in the center of the aperture.
Due to the choice of the feed, the size of the paraboloid and the magnitude of the focal length, the required radiation pattern of the satellite dish is obtained. Antenna radiation patterns different depths mirrors are also different, because they have a different distribution of field amplitudes in the aperture of the mirrors. Shallower mirrors are irradiated more evenly, so the main lobe is narrower and the side lobes are enlarged. It is possible to obtain a given amplitude distribution in the antenna aperture different ways:

• By choosing an irradiator.
• Using two-mirror antennas.
• The shape of the mirror, and its modifications.

In conclusion, we give advice, how to choose the size of the plate yourself... The smartest thing to do is to look at a coverage map. the desired satellite and determine from the irradiation power what is the minimum antenna diameter required.
For example, on the sites http://www.flysat.com or http://www.lyngsat.com.

How to choose an antenna (dish) for Russian satellite operators

Based on the above information, when considering the irradiation zones of satellites, you can select the size of the satellite dish for watching TV channels of each of the Russian satellite operators... The irradiation zones and the power of the satellite signal distribution in the irradiated zones can be viewed on the website pages:
Tricolor TV transponders and irradiation zone >>
NTV Plus transponders and irradiation zone >>
Transponders and radiation area Continent TV (Telekarta) >>

In this article, we will take a closer look at different kinds satellite antennas, we will tell you about the rules for their installation, the specifics of setting up equipment and operation. After reading the article, you can do everything yourself - from purchasing to calculating the position of the "plate".

Basics of receiving satellite TV

Future satellite TV users do not need to go into detailed technical details but it doesn't hurt to know some of the basics. For example, existing signal standards, frequency ranges and some other details.

Common standards for transmitted signals:

• DVB-S Mpeg-2 - TV broadcast plus Internet. Almost all satellites existing today support this standard, as well as any satellite receiver commercially available.
• DVB-S Mpeg-4 - the standard is similar to the first one, with the exception of one point - it requires a receiver that supports the Mpeg4 format.
• DVB-S2 Mpeg-4 (DVB-S2) - relatively new standard television signal, internet signal. Requires appropriate receivers.

Frequency bands

Broadcast of TV signals and reception / transmission of Internet signals using satellites is carried out in two frequency ranges:

• Range C - to receive signals in this frequency range, a parabolic antenna with a large-diameter dish of 2.0-4.5 meters is required.
• Ku-band - reception of signals in this frequency range is possible using parabolic antennas with a dish diameter of 0.5-1.5 meters.

Parabolic Antennas

Receiving a television signal from satellites is possible using two types of antennas - offset and direct focus. These are parabolic antennas with three main nodes:

1. Reflective and focusing mirror (parabolic dish).
2. Illuminator complete with low noise amplifier and signal converter.
3. Support-rotary adjusting mechanism.

Irradiator(low-noise block converter) - it is a converter (popularly often called simply "head"), receives a focused signal, amplifies and converts it into an intermediate frequency signal suitable for processing by the receiver.

Receiver- a special electronic set-top box receiver, where decoding and conversion of an intermediate signal into a signal suitable for processing by a television receiver is carried out. There are many models of satellite television receivers, including those supporting technologies digital compression video signal MPEG-2 and MPEG-4. Receivers are usually sold complete with parabolic antennas.

Typical receiver designs:

• conditionally coded (paid) access;
• access via smart cards (receivers with a card reader);
• access through the CI-module (receivers with TV signal decoding);
• Free public TV (FTA series receivers).

Types of parabolic antennas

Offset satellite antenna - a design that has a slightly shifted focus relative to the center point of the dish, so the actual direction of offset antennas is usually just below the satellite's horizon point. The antenna disk is usually located vertically relative to the earth's surface. The "offset" is usually installed on the wall of the house. Offset designs are designed to receive a Ku-band signal, but can also work in the C-band if the "dish" mirror has a diameter of more than 1.2 meters. Advantages - high accuracy focusing. Disadvantages - insufficient protection of the converter from impact external environment... This is the most common variant of "plates" in the private residential sector.

Direct focus satellite dish- here the focus is located exactly in the center. The diameter of the mirror of such structures varies in the range of 0.9-4.7 meters. Installation usually requires a horizontal support. Advantages - collapsible design of the mirror, which is of no small importance for large sizes. However, for the same reason, disadvantages appear in the form of poor focusing and, as a consequence, losses of up to 10% efficiency. This type of antennas can be considered universal - they are designed to receive a signal of both C and Ku-bands.

Attention! Satellite antennas are highly directional devices. Regardless of the design, the installation is carried out taking into account the mandatory orientation of the device to the southeast, south or southwest (depending on the specific satellite). In other words, the installation of the antenna should be carried out in a place where the coverage of the indicated directions is ensured (optimally - all three).

Offset antennas. Build and install

Assembling an offset satellite dish is not as complicated as it might initially seem. Usually bundled with the purchased device comes detailed instructions on assembly. The task is to connect the plate with the bracket, assemble the rotary mechanism and install the antenna converter holder. After assembly, the swivel mechanism must ensure the movement of the mirror with some effort, both vertically and horizontally.

The structure is delivered to the installation site and mounted on the wall of the house. Previously, on the wall, you need to mark and make several holes for the anchor bolts. Anchor bolts are installed, the antenna bracket is attached. Then it remains only to fix the converter itself on the converter holder and connect everything with a signal cable according to the scheme: antenna converter - receiver - TV.

Direct focus antennas. Build and install

The procedure for assembling a direct focus antenna is somewhat more complicated than an offset one, but many can also do such work. The mirror of direct focus antennas, as a rule, is collapsible, consists of several segments that form a dish as a whole. In the case of a private house, the plate is collected on the ground and then rises to the roof. Since the roofs of private houses are predominantly pitched, you will need to make a special stand.

Antenna stand - as an option, a prototype of a staircase with a riser, given that direct focus satellite antennas are mounted on a horizontal surface. The stand is mounted on the roof slope and the antenna mirror is mounted on the stand together with the support "leg" and the adjustment mechanism. Options for mounting on a rod, on the wall of the house are also not excluded if they provide an unobstructed direction of the antenna to the satellite.

Setting up the satellite TV antenna

You can start tuning under the following conditions:

• the satellite is selected - the translator of the television signal;
• the space in front of the antenna mirror is free for the signal to pass through;
• the TV screen is available for review by the tuner or the assistant to the tuner.

Satellite selection

The list of operating satellites is wide enough. Naturally, the user options are quite extensive, but at the same time they are limited. geostationary orbit satellites. All satellites are in the sky: southeast - south - southwest. In this case, the greatest angle of elevation of the satellite in relation to the horizon line is exactly in the direction to the south. That is, the greater the deviation to the southeast or southwest, the lower the satellites are located above the horizon.

Interesting TV satellites:

• YAMAL 201 / 300K, orbital position - 90 ° E e. Coverage: the entire territory of Russia, plus neighboring countries. Open access to the popular C and Ku band center channels.
• EUTELSAT 36A / 36B, orbital position - 36 ° E e. More than 150 channels from well-known operators "NTV-Plus" and "Tricolor-TV", including channels broadcast in HDTV format. Most of the channels are paid, but there are also free channels.
• HOT-BIRD 13B / 13C, orbital position - 13 ° E e. An impressive range of channels, including European ones. There are paid and free channels.
• HORIZONS-2 / IS-15, orbital position - 85.2 ° E Broadcast basis - paid packages Continent TV and Telekarta TV.

The list goes on. If desired, information on satellites is always available on the network.

Receiving data for directing the antenna to the satellite

To set up a satellite dish, you need the following data:

• the value of the orbital position of the satellite;
• geographical coordinates antenna installation locations (terrain coordinates);
• elevation angle of the satellite relative to the antenna installation site;
• azimuth value.

At first glance, it is quite difficult. But only at first glance. Basically, all marked data can be calculated using formulas.

Climbing angle calculation:

• F = arctan (/ sqrt (1 - Cos2 (g2 - g1) x Cos2 (v)])

Calculation of the azimuth value:

• Ф = 180 ° + arctan (tg (g2 - g1) / sin (v))

Where: g2- the value of the longitude of the area, v- the value of the latitude of the area, g1- the value of the longitude of the satellite.

However, if you have difficulties with higher mathematics, then it is better to use a special software(for example, by the program Satellite antenna Alignment), or get calculation data on specialized sites.

Installing the antenna in the desired position

So, the data is received. You can start setting the plate in the desired position, and then make fine tuning, focusing on the quality of the picture on the TV screen. Orientation of the device to the azimuth is done using a compass. Then a strictly vertical position of the plate is set. The exact vertical of the disc can be obtained by focusing, for example, on installed side by side plumb line. We have already obtained the value of the satellite elevation angle - using a regular protractor, try to bring the antenna to this value as accurately as possible, starting from the imaginary horizontal line formed between the center point of the converter head and the center point of the antenna mirror.

Further, slowly turn the dish to the right, left, while simultaneously controlling the appearance of the signal on the TV screen. If the signal does not appear, the ascent angle is changed by one or two degrees and the process is repeated. When a signal appears, they seek to obtain the highest quality picture and then finally fix the position of the dish.

Some features of the installation of satellite dishes

Modern satellite dishes can be completed with various accessories, the presence of which greatly facilitates the configuration process, and sometimes the user does not have to configure the equipment at all. Among these accessories:

• actuators
• moto suspensions
• positioners

For example, the SuperJack V-BOX II positioner provides full control satellite antenna by means of a swivel mechanism. The device's memory chips contain about a hundred orbital positions of satellites. Supports both local mode control, and the mode of control of commands coming directly from the satellite.

STRONG SRT DM2100 DiSEqC

Motorized suspension or swing motor. An example of such a device is the Strong DM2100 DiSEqC system, which is capable of tracking satellites located from 30 ° West longitude to 90 ° East longitude. The system also has pre-programmed installation data for over twenty popular satellites. True, this motorized suspension can be used only with parabolic antennas with a diameter of no more than 1.2 meters. Works with receivers using DiSEqC 1.2 protocol.

Lightning protection Dr. HD

Like any antenna system, the satellite one also needs lightning protection. Everything is quite simple here. There are special compact inexpensive devices like Dr. HD / Prof GC-862BL, which reliably protect not only the antenna, but all the equipment as a whole.

For modern world characteristic development information technologies at a fast pace. Therefore, the means of transmitting information are also significantly improved. After all, they should provide more high quality and processing speed. One of these areas, which have become widespread, has become satellite connection... It is used in many fields of human activity: from large industrial developments to small households.

One of these developments is satellite television. Now it is already very difficult to find at least one apartment building in which at least several would not have been installed.This is not surprising, because for enough small fee you can get great quality broadcasts television channels from all over the world.

There are two main types of these devices: direct focus and offset antennas. Their main difference from each other lies in the location of the place of the received signal. Also, the dimensions are not the same.So, an offset antenna has not big sizes, and the point where the converter is placed (it is reflected into it) is shifted relative to the geometric axis. A direct focus antenna is characterized by large dimensions and, accordingly, reflection to a point located on the geometric axis.

An offset antenna works on the principle of signal reflection from the front of the parabola into a converter. In this case, only a part of the entire branch of the parabola is used. A large offset antenna has a full-face look of an egg, those that are smaller - a circle. Large devices include devices with a minimum diameter of more than one meter. To small ones - less than a hundred centimeters.

But it is worth noting that an offset antenna cannot be used to receive a professional television signal. This is due to the fact that when reflected on the converter, an uneven spot is formed.

To install offset ones does not require a significant investment of time and energy, since these devices must be fixed almost vertically, and this greatly simplifies their mounting on a balcony or simply on a wall of a house.

Also, this device has one important advantage: any do not linger on the reflective dish. All these parameters contributed to the widespread use of similar devices to connect satellite TV.

Offset antennas can be executed from different material: plastics, steel, mesh, aluminum - all these can form the basis for the production of reflective surfaces. Each of these devices has its own disadvantages and advantages. So, for example, plastic antennas are highly susceptible to the influence of temperatures, but they are much lighter in weight and more convenient to install. Steel, on the contrary, is heavier, but much stronger and more reliable. Although antennas made of this material have one property that negatively affects reception - they rust over time.

The modern market will provide you with a wide range of goods, so you can always choose exactly what is right for a particular case.

People who are faced with the choice of a satellite dish for the first time, first of all, pay attention to its size. And this is correct, but there are still many factors that need to be properly assessed. This is a form, a material of manufacture, there are also perforated plates, mirrors and many more different designs, the variety of which can make your head spin. In addition, when choosing a plate, you need to decide on following properties:

Satellite reception area;

What channels are you interested in;

Is it possible to tune in to the satellite: are nearby buildings and other objects interfering .;

A dish is selected for one satellite or for several;

The economic component.

Direct focus

The task of a satellite dish is to collect and focus the signal to one point. With a direct focus, the beam is focused directly in the center, it is tuned immediately exactly to the satellite. The focus is the place where the converter is mounted on metal rods. Both the converter and the holders cast a shadow on the mirror, reducing the useful coefficient of the reflective surface. Therefore, plates of this type are more effective with a large diameter - from 130 cm.

In addition, when adjusting the direct focus dish, the degree from the horizon can be up to 20%, so snow ice, water, leaves, dirt can remain in the bowl, which settle on the reflector and also significantly impair the reception of codes. Direct focus is preferred if it is planned to receive a signal from distant satellites.

Offset

For offset - the focus center is slightly shifted down and it is set almost vertically. It cannot boast of such signal quality as direct focus, but it catches well with a small diameter of up to 150 cm, is easier to install and does not need to be cleaned. Therefore, it is better suited for domestic use.

Satellite, 2-mirror, toroidal multifocal dish

Satellite, 2-mirror, toroidal multifocal dish allows you to simultaneously receive a signal from 16 satellites. This is a great alternative to a motorcycle suspension. In addition to the elevation and azimuth in this antenna, the tilt of the mirror is also adjusted, depending on the geolocation of the reception and the satellites you are going to aim at. The antenna picks up a signal in a sector of 40-60 degrees.

The most important thing when buying such a plate is to distinguish the original from the fake. This can be done indirectly by the weight and quality of the metal. Fakes are made of thinner metal, which is less effective in keeping the geometry of the cymbal.

You can also pay attention to the prefabricated petal plate. It is more convenient for transportation and is suitable if you set the plate for the summer in the garden, and at the end of the season you take it to the city. Its only drawback is fragility, so you need to handle it very carefully.

Solid or perforated

The antennas are perforated only to reduce windage and weight. This is important if the equipment is mounted on a mast. A gust of wind can give a load of up to 200 kg and the perforated mirror is guaranteed to withstand it. Perforation does not in any way affect the quality of the signal, which is reflected in exactly the same way from both perforated and solid surfaces. Such devices are brought from abroad, therefore, they are more expensive than conventional ones.

Choosing the type of suspension

This is another one important parameter when choosing an antenna. Simple and cheap azimuth suspension allows you to tune the equipment to a specific satellite. To pick up a signal from another, you will have to carry out a complete readjustment.

The more complex and expensive polar harness is customizable. It allows you to tune your dish to several satellites in different orbits.

Manufacturing material

Satellite dishes can be found in aluminum, steel and plastic. Aluminum plates are quite expensive and, of course, surpass the others in many characteristics, including corrosion resistance. However, they are more susceptible to deformation due to the softness of the metal. Deformation of the cymbal can greatly impair the quality of its reception. Most often, aluminum plates are used for mounting on a motorized suspension with fast switching between channels from different satellites. Due to its light weight, it places less stress on the gears.

If you increase the size of a steel plate, then it will receive a signal at the same level as an aluminum one, cost 3 times cheaper and will last at least 10 years. However, such a tray is heavier and more susceptible to corrosion in the presence of coating defects.

Plastic plates are more fragile, especially in winter and are prone to deformation under the influence of sunlight and temperature extremes. Although, the more stiffening ribs on the plate, the more durable it is. Snow also adheres to them. Therefore, they are not particularly popular.

Thus, inexpensive and functional steel plates are more in demand. However, there are no arguments against the purchase of aluminum plates, if financial resources permit.

Size is the main thing !!!

Size is the defining parameter. It is for this situation that the definition fits: the more the better. The difference in signal reception between a 55 cm and 90 cm dish will be very noticeable. There are no clear guidelines for what size antenna to buy. When choosing, the principle of practical rationality should work. It is only necessary to take into account the additional tolerance if the plans include a desire to reconfigure the equipment for one more satellite. The tolerance should not be large, so as not to overpay for extra centimeters.

The choice of diameter depends on the signal strength level in your area. It is determined by the coverage map of each specific satellite. In other words, the choice of the diameter of the satellite dish directly depends on the location of the buyer. Remember to make allowances for the weather. Large operators satellite television supplies to their dealerships sets of equipment with a mirror diameter already calculated for a specific area.

It is believed that for tuning to more than one satellite, the optimal dish diameter should be 120cm, for one satellite 90cm is enough.

We work seven days a week !!!

Today more and more people are purchasing satellite dishes, which are usually called satellite dishes. So let's look at what they are and what they are.

What it is
The "dish" itself is a reflector, something similar to a mirror, which concentrates the waves falling on its surface on a receiver, which is called a converter, and the converter converts the signal and transmits it to the receiver. And already from the receiver, the signal goes to the receiver, TV or computer. This is the principle.

What are satellite dishes
Satellite antennas are direct focus and offset.

Direct focus - this is when the antenna mirror has the shape of a parabola cut, the satellite signal is reflected to a point on the parabola axis, where the converter is attached. Depending on the distance of the converter attachment, there are short-focus and long-focus antennas, but we will not delve so much. Direct focus antennas have their own advantages and disadvantages.

Advantages
Since the shadow from the converter covers the honor of the area of ​​the dish, degrading the signal quality, they are made large in order to get rid of this disadvantage. And since they are large and the converter is located on the axis, the signal is focused at a point with good quality... Therefore, such antennas are used, as a rule, for professional work.

Flaws
The disadvantages include mounting problems, such antennas have a large tilt angle to the horizon, as a result, water, snow, dirt accumulate in the antenna, deteriorating the quality.

Offset antennas
Such antennas seem to use part of a parabola, as a result, the point to which the rays are reflected is displaced and the installed converter does not cover the antenna mirror. Offset antennas reflect an uneven spot on the converter, because of this, the signal quality is worse than that of direct focus antennas.

The advantages include the fact that they are easy to install and are placed almost vertically, as a result, sediments and dirt do not accumulate in them.

Material
Today antennas are made from steel, aluminum, plastic, even mesh.
Aluminum
In our region, aluminum antennas are common, as a rule, they are lightweight, do not corrode, and reflect the signal well. But they have one drawback, they are not very durable.

Steel
Steel antennas are robust, but heavy and corroded, which degrades the received signal quality.

Plastic
Plastic antennas reflect the signal well, they are lightweight, but in regions with a large temperature difference, they become unusable. The plastic loses its shape, cracks, which leads to a decrease in the signal quality.

Mountings
Suspensions for satellite dishes are divided into two types.
The first is an azimuth suspension and is used for antennas aimed at one satellite.

The second is polar, it allows you to tune the antenna from one satellite to another.

Converter
This is a device in the center of the dish that converts the signal and transmits it to the receiving device. Converters are for different ranges and the main indicator of their quality is the noise level, which should be within 0.6-0.7 dB. If you expect to watch TV from one satellite and work on the Internet, then you will need a converter with two outputs.

Conclusion
In conclusion, I would like to note that when buying a satellite dish, the most the best option it will be if you immediately conclude an agreement with this company for the installation of all equipment, which will avoid many problems and, most importantly, complications in the operation of the system.