Satellite television has long and firmly entered our lives. Thanks to this technology, people have been able to receive a high-quality television signal even in the most remote places where it is not possible to install repeater towers.

As a rule, to receive a signal from a satellite, it is necessary to have a set of special equipment, one of the important parts of which is a satellite dish. Usually, this part is a round sheet of metal, which is stamped in the form of a concave parabola with certain dimensions. Due to the curvature of the surface, the signal is reflected from it and focused on a special receiver, which then transmits it to the satellite tuner.

If you do not have a factory plate at your disposal, then you can make it yourself. With careful manufacture, such a plate will be quite efficient, and its cost will be a very attractive figure.
Consider the most common options for making plates:

Parabola made of plexiglass or plexiglass

One of the distinguishing properties of this material is that plexiglass becomes plastic with moderate heating and can take the form of the object (blank) on which it is placed. Therefore, you can take a blank of plexiglass with a thickness of 3 ... 5 mm and a circle diameter with a size slightly larger than the diameter of the original factory-made plate. After the plexiglass softens under the influence of heat, it is carefully leveled on a blank, trying to give the most similar shape. After the plexiglass has cooled, its concave surface is evenly pasted over with thin foil, which will work as a reflector. The disadvantages of this method of manufacturing a satellite dish include the high cost of plexiglass and the need for a heating chamber with a large internal volume.

Satellite dish made of thin sheet metal

For the manufacture of this option, we need a sheet of thin galvanized metal 1 ... 1.5 mm thick with dimensions of approximately 100x100 mm. From it you can make a plate with a diameter of about 80 mm. To properly mark and cut the metal, we first take cardboard right size and draw it into 16 identical circular sectors (each sector is offset relative to the previous one by about 22.5). Then we draw 4 circles with radii of 75, 254, 400 and 538 mm, respectively. The last circle will go beyond the cardboard square, so just cut off those pieces of it that will be outside. On these circles, we will then bend the template. At the next stage of manufacturing the template, we make cuts along all 16 rays, maintaining the distance C1 ... C4. Dimensions C1=0 mm, C2=11 mm, C3=29 mm and C4=50 mm.
After the cutouts on the template are ready, they are transferred to a sheet of metal using a metal ruler and a sharply sharpened scriber. Using scissors for metal, carefully cut out the blank (cutting out) of the future plate. At the last stage, the metal petals are interconnected and a finished antenna mirror is obtained.

Parabolic wire antenna

To make such an antenna, you need a large inflatable ball. It will serve as a template for the wire frame of the antenna. On the ball with a pencil, mark the maximum radius of our future plate. That smaller part of the ball, which will be separated by a drawn circle, will be a curved surface. Then we take a coil of copper wire with a diameter of 2 ... 3 mm (for example, wound from an old electrical transformer) and make circle No. 1 out of it, which is placed on the ball. The next wire circle (No. 2) we do a few bigger size so that the distance between it and the previous one is about 20 ... 30 mm. Thus, we gradually reach the maximum diameter that we need. We connect the finished circles with radial rays, and the intersections are either twisted with a thinner wire or soldered with tin solder. We leave the place inside the smallest circle empty - then the plate rack will be fixed there. We carefully wrap the finished frame with aluminum fine-mesh mesh or foil so that the specified curvilinearity of the reflective surface is observed.

If the house is located far from large cities, and it is not possible to buy a satellite dish dish, you can build a simple antenna to amplify the signal. In this case, the TV tower should be 30-50 km away from the house, and the signal should have sufficient strength. If there is a water tower or any other high structure near the dwelling, then the task will be greatly simplified.
To make such an antenna, you need an old umbrella, a roll of foil, a copper antenna cable, a beer can and an amplifier with a power supply.

Despite the name, the article below will not tell you how to make a satellite dish yourself or solder a receiver. Just a note about what you need to purchase and how to install and configure everything yourself in order to watch TV channels "on a plate".

Suppose you live in a country house, in a village, or simply "away from civilization". But I want to watch TV, and not a couple of channels that are broadcast on the air.

(Small digression: on this moment terrestrial digital broadcasting is actively developing. Find out if the number of channels you need is available in your area via terrestrial digital television? In this case, you will only need a prefix for receiving digital signal(if the TV does not support), and the antenna can not be changed.)

And so you decided to get satellite equipment for watching a lot of TV shows. First you need to decide: what channels do you want to watch? If your goal is various Discovery, Viasat and / or purely sports channels, then we immediately inform you: it is better to conclude an agreement with one of the companies providing satellite television services for a subscription fee. Such channels are transmitted in encrypted form and only some of them can be viewed "on the ball". Fortunately, in our time, companies involved in the installation of satellite equipment and the provision paid services enough. You can order the installation even in the middle of nowhere, the only question is the cost.

If you decide to go this route, here are some tips:
1) if there are several offers, carefully study the list of channels provided in a particular package, the need to pay extra separately for sports, educational channels, etc.;
2) opportunity free installation equipment by the company's specialists;
3) Is there a separate charge for "kilometers to the client" at check-out?
4) it is not superfluous to pay attention to the reputation of the company: read on the Internet, ask around from customers;
5) to find out if the reception on the signal equipment installed by the company is of high quality in your area;
6) it is often possible to profitably connect (for example, equipment or installation at a penny price, half of the subscription fee for some time for a more expensive package, or even a couple of months of "freebies") for various promotions; as a rule, to attract customers, large firms hold them regularly: New Year, for the anniversary of the company, etc.;
7) well, and advice that is suitable for any transaction: carefully read the contract to be signed BEFORE signing, and not after, having come home and relaxing at your favorite TV channel; it may well be that a profitable, at first glance, action obliges you to use the services for at least a couple of years after the conclusion of the contract, otherwise they will write off the penalty, etc.; in general: be always on the alert! and enjoy watching!

For the same who decided to do everything himself material below.

Again, to begin with, let's make a reservation: this information will suit most of all those who live in the European part of the former USSR.
So what is needed?
For starters: desire! The desire to do everything yourself (well, or with someone's help). Without this, you may not reach a successful final. Then patience, a firm hand, a minimum of tools, and a little Money. About the last one. A lot depends on where, what and from whom you buy. But even when buying everything new, you can easily invest in the equivalent of 100 UDS, unless, of course, you are chasing branded equipment. And it doesn’t always make sense to buy everything new, for example, if there is a profitable second-hand offer on the market. The same plate or receiver is not a flash drive: they can work for a very long time and with high quality (although flash drives come across reliable :)).

And again a small digression: introduction to the world of satellite television. What is it all about? First, let's take a look at Wikipedia.

Geostationary orbit (GSO) - a circular orbit located above the Earth's equator (0 ° latitude), being on which, artificial satellite revolves around the planet with an angular velocity equal to the angular velocity of the Earth's rotation around its axis. In the horizontal coordinate system, the direction to the satellite does not change either in azimuth or in height above the horizon, the satellite "hangs" motionless in the sky.

Those. somewhere high in space, at an altitude of about 36 km from the Earth's surface, an artificial satellite of the Earth, which is a powerful television signal transceiver, rotates synchronously with it. It picks up the signal from high power(powerful) terrestrial transmitting antennas and transmits it to a large area below it. In fact, there are many satellites. Each of them broadcasts to a certain territory according to the direction of its transmitting antennas. Several conclusions follow from this: the satellite is very far away, it is limited in mass, volume, power supply capabilities, it cannot be repaired in case of emergency, hence the complexity, duplication of systems, etc. From all this, the conclusion is: the power of the transmitting signal is limited, the signal from the satellite is very weak.
Then, the satellite is expensive, which means it must be used to the maximum: transmit through it as much as possible more channels over a large area of ​​the earth. The second conclusion is that conventional technologies, which are still used in our country for the transmission of on-air television and radio broadcasting, are not suitable - the number of transmitted channels is too small. Therefore, satellite television uses modern digital data transmission methods. The third conclusion is that all channels cannot be "stuffed" into one satellite for technical and organizational reasons.

Now let's see: what do these conclusions turn to us?
Reception technology needed weak signal. For this, a parabolic antenna is used. Here - the larger the area of ​​the parabolic mirror - the better. Better for a signal that is collected and focused to a point. But the larger the antenna, the more expensive and heavier it is. It is more difficult to mount it, and fixing it securely to counteract a strong vert is generally a problem at home, as a rule. Therefore, in practice, they choose a size sufficient for high-quality reception, and this is for most of Eastern Europe a diameter of 0.8 meters or more. One of the most common diameters is 0.95 m.
There are two main types of satellite dishes: direct focus and offset. The former have a signal receiver (feeder) at the focus of the parabolic mirror, which coincides with the geometric one. For the latter, the signal collected at a point from a parabolic mirror is reflected to a point below the geometric center of the antenna. This eliminates the shading of the useful area of ​​the antenna by the feed and its supports, which increases its efficiency with the same mirror area with a direct-focus antenna. In addition, the irradiator is installed below the center of gravity of the antenna, thereby increasing its stability under wind loads. The offset antenna mirror is mounted almost vertically. Depending on the geographical latitude, the angle of its inclination varies slightly. This position eliminates the collection of atmospheric precipitation in the antenna bowl, which greatly affects the quality of reception. In the light, the antenna is not a circle, but an ellipse, elongated vertically. Offset antenna sizes are usually given in terms of gain equivalent to direct focus antennas. If horizontally this size is the same, then vertically it will be approximately 10% larger.
In the future, by satellite dish we will mean only offset, as the most common.

Direct focus antenna.

offset antenna.

A distinction is also made between fixed and movable antenna mounting. In the first case, the antenna is fixed to the base, in the second - to a special positioner. The task of the latter is to rotate the antenna in an arc for positioning on the desired satellite. The turn signal is usually satellite receiver. It takes some time to accurately position to the satellite when you select a program from a different satellite than the current one. Technically implemented using a motor-actuator. Expensive, and, accordingly, not often found solution. It will not be considered in the practical part.

As mentioned above, the signal from the antenna is focused to one point, where a device called a converter is installed (LNB head or low-noise block converter or low-noise monoblock converter). Based on the name "satellite converter", it immediately becomes clear that this device converts (converts) something. An electromagnetic signal comes from the satellite, which is focused by the satellite dish on the converter and converted by the LNB head into an intermediate frequency. This is necessary so that the signal can be efficiently transmitted further along the cable. In addition, the LNB head amplifies the received signal. Further, the signal via the coaxial cable from the LNB head goes to the satellite receiver, which, as a rule, is made as a separate device (the so-called satellite set-top box), but can also be built into the TV.
Due to the fact that the satellite is very far away from the receiving antenna, you have to direct this same antenna very accurately at the satellite itself.
To summarize: in order to receive satellite television, it is necessary, in addition to the TV itself, to have the following equipment.
1) Parabolic antenna with a diameter of 0.8 m.
2) LNB head.
3) If you want to watch TV programs from more than one satellite, then you need a switch (switch) of DiSEqC heads.
4) Coaxial cable.
5) Satellite receiver.

This is where the theoretical part ends. Let's move on to the practical.

First, determine a place to mount the parabolic antenna. The height above the ground does not play a special role. It is important that there are no obstacles on the satellite-antenna line. Even tree crowns. For residents of Eastern Europe, the direction to the satellite will be south with an offset to the west or east, depending on the coordinates of the antenna and satellite. After all, we remember that geostationary satellites are launched into equatorial orbit.
The place for mounting must be strong and securely fastened: even the slightest vibration of the antenna will lead to signal loss. The best option is the main wall of the building or the reinforced concrete roof slab. But other options are also suitable, for example, a rigidly fixed vertically installed iron pipe of such a diameter that it does not sway when the wind gusts. Depending on the selected mounting option, select the appropriate fastener, which is fixed on one side to a fixed surface, and the antenna itself is attached to the other. As a rule, the antennas themselves are not equipped with such a part. It can also be a homemade product, the main thing to remember is that the antenna has a large windage and it will need to be accurately directed to the satellite, i.e. the reliability and ease of installation and configuration of the antenna itself is important.
Then choose, in fact, the antenna. Here it is better to ask the owners of satellite equipment in your area what diameter of the "dish" they use and whether the reception is good during thick clouds and / or rain. If, for example, it turns out that when receiving on an antenna with a diameter of 0.8 m, there is a signal loss during heavy rain, then you should think about purchasing an antenna with a diameter of 0.95 m. At the same time, overpaying for a "dish" 1.5 m in diameter does not make sense. In addition, it may turn out that the person who provided you with the above information simply does not point the antenna accurately enough at the satellite. In general, the advice of those who know and the experience of neighbors with "plates" will help here.
After that, it is worth deciding from how many satellites do you want to watch TV programs? In theory, you can "overgrow" with antennas like mushrooms after rain, but in practice the most common option is one "dish", a mount for three receiving heads, three LNB heads, a DiSEqC switch for 4 heads, then a cable from DiSEqC to the receiver, the receiver itself, and from it to the TV. This is the so-called multifeed scheme. Let's look again at Wikipedia.
Multifeed - a set of devices (in particular, converters) designed to receive a signal from several satellites on one parabolic antenna. A multifeed is often called a bracket on which additional converters are mounted.

Such a scheme has been worked out for years, it allows you to watch a maximum of Slavic-language programs with a minimum financial investment. With three LNB heads, manually, without resorting to special equipment, it is possible to adjust the acceptable signal quality to the three most popular satellites in Eastern Europe: Amos 4W, Astra 4.9E, Hot Bird 13E.
The beauty here is that you can use one antenna for these satellites. First, an antenna with a central head is tuned, as a rule, on Hot Bird 13E, although it can be on any other. This changes both the position of the cymbal itself and the head to achieve the maximum signal level. The signal from this satellite quality setting will be the strongest. Then two others are tuned, but only by means of the heads themselves.
The most common type of LNB head is for one output, as the most popular and cheapest. From it, the signal goes through the cable to the DiSEqC switch or to the receiver. With this scheme, it is possible to serve only one TV with a signal. But there are heads for more outputs, which allows one antenna and LNB head to supply a signal to more than one receiver, thereby saving on equipment. This is very convenient if, for example, there is more than one TV in the house.

LNB heads: with one outlet and four.

In the second case, all 4 outputs can be connected to different receivers or DiSEqC. The receiver can simultaneously work with only one LNB head, and this is where the DiSEqC switch is needed if you want to watch several satellites on one "dish". Depending on the program selected by the user, it connects one or another LNB head to the receiver and supplies it with the supply voltage necessary for the operation of the head. In the vast majority of cases, there is only one DiSEqC between the LNB head and the receiver, but there are intricate schemes with cascading DiSEqC, but these are such rarely requested cases that we will not consider them.

Next, you need a coaxial cable to connect the DiSEqC and the receiver. It must be taken with a margin of a couple of meters relative to the distance that you are measuring. But remember that the longer the cable, the more loss it has.

It's time to talk about the receiver. This is a very broad topic.
For most TV lovers, the simplest receiver, such as the Orton 4100C, will do. But general information on choosing a satellite set-top box will not hurt anyone.

First of all, if you have a modern TV, then look at its instructions or read it on the Internet - it may happen that the necessary digital signal receiver is already built into this TV. If not, then here's what to look out for.
1) The number and type of signal outputs, as a rule, there should be at least three of them: a regular antenna output, SCART, a regular Video-out. In this case, it is easier to avoid a conflict when connecting if there is other video equipment that is also connected to the TV, such as a DVD or BLUE-RAY drive, game console, digital terrestrial television receiver, etc.
2) Does the receiver support HDTV (high definition television) reception? In our area, this is still a curiosity - the presence of clearly broadcasting (in the native language) HDTV channels, and even those that you can watch for free, but time does not stand still.
3) Availability of instructions in an understandable language.
4) Number and type of service connectors. They are necessary for flashing the receiver. Flashing is necessary to fix errors in the current firmware or to update the channel list. (Yes, yes, the receiver is the same specialized computer as a telephone or a router, and it also needs to “fill in” something from time to time). Ideally, there should be two such connectors: RS-232 (pins in two rows) and USB. If there is no USB, then it is not a fact that your computer has RS-232 (aka COM port), but if you wish, you can buy an RS-232-to-USB adapter. You will also need a so-called null modem cable. If there is no RS-232 on the receiver, but only UBS, then this is not so scary, because any (well, almost) Personal Computer older than 1996 has at least one USB port.
5) As a consequence of the previous paragraph - it is very desirable for the receiver to easily find the firmware, for example programming code from the manufacturer, and the list of channels - on a specialized website, or both in the second place. There are many options for popular models, but for exotics you will have to look. But you have to be careful, it's not so hard to screw up the receiver.
6) If it is not possible to flash the receiver, then it must support the addition of satellites and channels, entering keys, in manual mode from the remote control. This is a tedious business and requires care, but there is less chance of completely disabling the equipment. Although ... in capable hands ...;)
7) If there is a desire now or in the future to watch paid channels, then the receiver must support special security cards with keys. This means the presence of a special connector and firmware support.

Satellite dishes have somewhat lost their significance for society in recent years. The reason is the appearance on sale of digital TV set-top boxes. Nevertheless, this equipment remains in demand, especially if the population lives outside the urban area.

Buying equipment is not a problem, but installing a satellite dish may well become a serious task with an independent approach to installation. However, the task can be greatly facilitated if you have basic knowledge. We will talk about how the installation is carried out using the example of the popular Tricolor system.

Even when dealing with a traditional television antenna, and in such cases, installation requires at least minimal knowledge and skills. Satellite equipment is much more complex than conventional TV reception.

If conventional equipment has two main concepts - a cable and a plug, a system where reception from a satellite is carried out has a number of technical concepts:

1. Satellite antenna.
2. Converter.
3. Multifeed holder.
4. Bracket.
5. Receiver.

Let's take a closer look at each of constituent elements satellite equipment.

– signal source to be received by the antenna. Accordingly, in order to receive a constant signal, a constant direction of the antenna to the satellite is necessary.

The device in the geostationary orbit of the Earth, in fact, is a standard space satellite, but the main functionality of such a device is the broadcast of a television signal

There are different satellites and different antenna designs, but the principle of tuning is almost the same for all.

For this television reception technology, a satellite dish is used, which is a “dish” disk of different diameters, equipped with a conversion device - converter.

Part of the equipment is an antenna that provides reliable reception of the TV receiver signal from the satellite. Given the frequency of the transmitted signal, the antenna looks somewhat different than traditional reception designs.

This is a module of small geometric dimensions, usually cylindrical, attached directly to the "front" part of the satellite dish.

The disk antenna has a special design that allows you not only to receive a television signal, but to additionally concentrate and direct it to one point - namely to the converter. It, in fact, is the primary signal amplifier, from which the signal is fed through the cable to the receiver.

One of the components of a satellite dish that needs special attention during installation, ensuring a high degree of tightness of the structure

A special rod holder is used to fix the module. The device called "multi-feed-holder"- this is the same rod-holder, only slightly modified. Allows you to place several converters to work with different satellites.

The bracket is, in fact, a mechanical structure that is assembled from component parts and fixed at the intended installation site of the satellite dish. As a rule, such a place is the wall of the building, less often the roof truss system.

The so-called "multifeed" - in simple terms- Extended bar. This is a holder of several converters at once, designed to receive signals from different satellites

The electronic module for processing the received television signal, with the subsequent display of information on the screen of the television receiver, is called receiver.

There are different designs of receivers depending on the manufacturer. However, a specific manufacturer, as a rule, completes the equipment taking into account the correspondence between the antenna and the apparatus.

The design of the bracket involves not just a conventional stationary mount. The mechanical part has a simple, but quite effective system of shifting vertically and horizontally

Therefore, it is rather problematic to match any receiver (receiver) with any "non-native" antenna. This point should be taken into account before installing it in the house with your own hands and holding it under a modern TV.

The receiving module is also a “receiver” of the signal, which does not need to be installed like a satellite dish, but requires some settings from the end user

Selecting a suitable location for equipment

First of all, you should choose the optimal location of the satellite dish. What is meant by the term "optimal"? Of course, a completely free area in the direction of the transmitting satellite.

That is, in a given direction, the presence of any objects similar to:

• buildings;
• trees;
• advertising posters, etc.

It is also recommended to ensure the maximum possible proximity of the placement of the rest of the equipment (receiver, TV) to the installation point of the satellite dish. These are not critical requirements, but the fulfillment of these requirements will help to simplify the setup of the equipment.

Tuning antenna circuit: 1 - direction "north"; 2 - direction "south"; 3 - azimuthal direction; 4, 7 - angle at the installation site relative to the location of the satellite; 5 - television satellite; 6 - satellite signal

Traditionally, "plates" are placed on the wall of the building next to the window opening, or the installation is done on the side of the wall, which is part of the balcony (loggia) structure.

The instruction prohibits installation directly inside the balcony area, especially the glazed one. Also, the equipment should be installed at points where there is no possible fall of precipitation in the form of snow and ice from the roof.

Step-by-step instructions for mounting the plate

It is first necessary to assemble the satellite antenna structure as this procedure is described in the attached instructions. As a rule, antennas are delivered unassembled. Therefore, the structure must be assembled using the supplied accessories.

Step #1 - Attaching the Antenna Bracket

Again, given the work with a proprietary product, where all installation elements and components are designed for the appropriate load, work is being done to install anchor bolts in the wall of the building.

One of the options for antenna brackets that are used for reliable, sturdy installation of a satellite dish. Initially, a support pipe is attached to the wall, and the antenna bracket is directly attached to the pipe

This work is done in a standard way, using a tool for working with concrete. After the introduction of the anchors, a support rod is attached to the installed anchors, and a metal bracket is attached to the rod.

Step #2 - Installing the Antenna Converter

Installation preamplifier signal - converter, carried out strictly according to the instructions, where all the subtleties of the placement of this component are noted.

The converter itself should be fixed in the support ring in such a way as to ensure perfect tightness of the device. Even a slight penetration of moisture inside threatens to disrupt the operation of the device.

Step #3 - Connecting the Cable to the Converter

At the current stage, the cable, which is usually also included in the kit, is connected to the converter module. The connection is made by means of the special “F” connector included in the scope of supply.

An example of a well-connected cable on the side of the converter. Well-executed sealing of the connection area is clearly visible, which will ensure stable operation of the amplifier for a long period of time

The connection area must be carefully sealed, for example with silicone sealant. The cable from the point of inclusion is gently and effortlessly pulled through the body of the converter holder rod. It is fixed at regular intervals with plastic ties or in another way.

Step #4 - Fixing the Satellite Dish

The prepared “plate” is installed on the bracket, while the adjusting screws are not tightened to the stop - they are left loose.

This approach is necessary for the simple reason that further (after installation) the procedure will follow fine tuning to the satellite. Accordingly, the “plate” will have to be moved both vertically and horizontally.

Installed, fully custom-made household "dish", ready to reward its master with a high-quality television picture received from a satellite

Separately, it is worthwhile to instruct on the installation of the F-connector on a coaxial cable. This operation has its own characteristics. The end area of ​​the cable (approximately 15 mm long) must be freed from the first insulating layer.

But you need to remove the insulation, taking into account the integrity of the screen braid present under the insulation layer. Then the second layer of insulation is removed over a length of about 10 mm. This releases the central copper core. Next, the connector is screwed onto the cleaned trailer until it stops, passing the copper conductor into the corresponding hole.

How to adjust the installed antenna?

Usually, the “dish” installation instructions contain a table where information on azimuth and angle is indicated - setting parameters in the direction. The parameters are indicated, as a rule, for the area where large settlements are located.

You should select the nearby territory from the list and take the parameters of the angle, azimuth for setting. Further, according to these parameters, set the antenna mirror by moving the "dish" in the vertical and horizontal planes.

This will be the "rough" setting. After which the antenna cable is connected to the receiver, and the receiver, in an appropriate way (also through the connecting cable) to the television receiver. Then it remains only to adjust the parameters of the angle and azimuth, achieving the highest quality picture on the TV screen.

Tuning table based on the location of large settlements, where the preferred parameter of the angle and azimuth under the direction of the antenna is indicated

Any receiver by default has a service for monitoring the level of the received signal. Using this functionality, you can configure the equipment with high accuracy. However, weather conditions can make adjustments to the setting. Therefore, it is recommended to perform tuning activities under conditions of a clear, cloudless sky.

Having achieved the appearance of a stable, sufficiently strong control signal on the TV screen, the mirror fastening nuts on the bracket are screwed up to the stop. The equipment on this is considered installed and configured.

Further, they are already moving to the usual user viewing using access cards or through free available channels. How, choose channels and open access - all this is in the user manual.

If a dish is installed in the country for regular viewing of TV programs, most often the signal received by the antenna needs to be improved due to the significant remoteness of the repeater. In this situation, it will help, with the rules for choosing which the article we recommend will acquaint you with.

Conclusions and useful video on the topic

Below is a video material where the home master explains from personal experience all the subtleties of installing the “plate”.

Accordingly, the whole process is filmed on a video camera, so the reader is clearly shown how with my own hands to install a satellite dish:

Despite the visible and invisible difficulties that manifest themselves in the process of installing a satellite "dish", it is quite possible to cope with such work with your own hands. The main point is scrupulous collection, processing up-to-date information and, of course, a careful study of the accompanying instructions.

Currently, in satellite direct television reception (SNTP), two main paraboloids of revolution are most widely used as antennas: axisymmetric and offset.

The complexity of manufacturing a parabolic reflector forced us to look for alternative antenna designs that are more technologically advanced in production and self-production.

These designs include a flat zonal Fresnel reflector (Fig. 6.17).

Auguste Jean Fresnel (1788-1828), a French physicist, one of the founders of wave optics, in the process of studying the diffraction of light, used the method of dividing the wave front into annular zones, later named after him.

The zonal Fresnel antenna (ZAF) according to the principle of operation differs significantly from the commonly used antennas based on a parabolic reflector.

The description of the antenna and the methodology for its calculation were compiled by V. Nikitin (Moscow) and the author of this book.

The Fresnel antenna reflector is a conductive concentric annular surface located in the same plane. Under the influence of an incident wave of an electromagnetic field, according to the Huygens principle, each ring becomes a source of secondary radiation, which is directed in different directions, in contrast to the paraboloid of revolution, which reflects all rays in the direction of the focus.

It is possible to choose such a width of each ring of the zonal antenna and the distance between them so that the signals of the secondary radiation from the center lines of each ring at a certain point in space coincide in phase.

To do this, it is enough that the distances between the middle lines of the rings and the indicated point differ by the signal wavelength - lv. This point, by analogy with a paraboloid, can be called a focus. At the focus, as in a parabolic antenna, is the feed.

On fig. 6.18 shows a section (side view) of the upper part of the central disk of the antenna and the first ring. If a point is chosen as the focus, which is at a distance f from the plane with rings, then the signals emitted by the middles of the rings will be in phase at the focus for the following values ​​of the distances between the edges of the rings and the focus:

The signals emitted by the middle of the rings are in phase with the signal emitted by the center of the disk. The skew between the signals emitted by the edge of the disk and its center, as well as the edges of the track and their middle, is only 1/4 of the wavelength.

Thus, the calculation of the AF is reduced to choosing the location of the focus F on the imaginary axis of the antenna, i.e., the distance f from the antenna web, and calculating the inner and outer radii of the rings depending on the wavelength l, the repeater according to formula (6.2).

The distance f is not critical and is chosen in the range of 500...1000 mm (for antennas of large diameters).

The signals emitted by the edges of the track are out of phase from the signals emitted by the circle (located in the middle of the ring), which ensures common phase. Wide rings provide broadband antenna.

Due to the fact that the AF track radii depend on the signal wavelength, it may seem that the antenna is narrow-band and for each frequency (or wavelength) of the satellite transponder, appropriate ring sizes will be needed. However, calculations show that this is not the case.

If the ring radii are calculated for medium frequency in the range 10.7 ... 11.7 GHz (wavelength 26.8 mm) or 11.7 ... 12.5 GHz (wavelength 24.8 mm), then for the minimum and maximum frequencies of the ranges, those circles that correspond to the equality of the phases of the signals will be located on the surface of the rings.

In table. 6.2, 6.3 shows the results of calculating the dimensions of the ZAF for the indicated frequency ranges. Ordinal numbers of radii were successively substituted into formula (6.2) as the value of n (even numbers correspond to the inner radii, odd numbers to the outer radii, and r1 to the radius of the central disk). The distance f from the central disk to the focus F is chosen to be 1000 mm. The width of the rings decreases uniformly. It is not necessary for a radio amateur to produce ZAF in full.

In cases where a parabolic antenna with a diameter of 90 cm is used at the reception point, the ZAF design can be limited to five rings (radii r10 and r11 correspond to the fifth ring). At the same time, for the frequency range of 10.7 ... 11.7 GHz, the diameter of the ZAF is 1098 mm, for 11.7 ... 12.5 GHz - 1024 mm.

Table 6.2

If we calculate the track radii for the average wavelength of the entire broadcasting range Ki (10.7 ... 12.75 GHz), at its edges these "in-phase" circles go beyond the surface of the rings. Therefore, at the edges of such a wide range of in-phase addition of signals is not obtained.

As a result of the calculation, the radii of "in-phase" circles are obtained, where n is the number of the ring. The central disk corresponds to n = 1. The width is chosen arbitrarily. In practice, it is possible to make a central disk with a radius of 50 mm, and take the width of each ring equal to 20 mm. In this case, the in-phase circle is approximately in the middle of the ring.

The zonal antenna is flat in shape, so it is much more technologically advanced in amateur manufacturing conditions. Such an antenna can be made from a large piece of foil plastic, either by etching, or by cutting gaps between the rings. It can also be made by sticking rings of foil or even sheet metal onto a sheet of getinax, textolite, plexiglass, wood-fiber cloth (MDF).

To reduce the wind load, an arbitrary number of holes are drilled in the dielectric base of the antenna.

The main disadvantage of a zonal antenna compared to a parabolic one of the same diameter is a lower gain, since not all of the signal energy falling on the antenna sheet is directed to the feed. In weak signal conditions, even a 2 dB loss of gain leads to signal damage by noise and loss of color.

To compensate for the lack of gain of the ZAO, it is necessary to increase the diameter of the antenna web, although with sufficient power of the satellite transponder and high elevation angles (thermal noise of the Earth is less affected), such an antenna provides good results for a given receiving point.

You can fix the converter in the ZAF focus in the same way as for a direct-focus parabolic antenna

It was a long time ago when they were still thinking about creating a homemade satellite dish. Buy Now satellite dish won't be difficult. They are at almost every turn.

But still, offset antennas are very large, more than 2 meters, and now it is very difficult to find or purchase, since the price will be prohibitive. A few years ago I had an idea how to create a satellite dish myself. Yes, it was possible to rivet a flat one, on Fresnel rings, but I simply did not like it.

A long time ago, satellite antenna mirrors were made of alabaster and cement.

Yes - the wind was definitely not terrible for such antennas. But you understand - such homemade satellite dish and the technology of its production is not for our time.

Some craftsmen later made a simple 0.6 m in diameter from epoxy resin and foil, or using mounting foam, while at the end of the description of their work, they indicated that it is desirable to install such antennas away from human eyes - so as not to laugh.

And the cunning Chinese simply rivet small-sized direct-focus antennas along with pots and bowls made of tin on an adapted lathe.

Of course, there are always gifted people, real specialists who do truly good things. Some did direct focus, and some did offset. I have seen pictures of an offset satellite dish about 3 m in diameter on the net. It's simply impossible to look at this without admiration. It's like an exclusive item.

Particularly noteworthy are home-made satellite dishes made of tin. There are also original solutions.

If you still decide to make a satellite dish yourself, some materials from the archive may come in handy

Calculation of satellite antennas instructions download