(preparing for setup)

On at this stage, we need to determine the approximate tilt of the mirror of our satellite dish in a vertical plane.

You can, of course, not calculate this parameter. But, knowing the correct tilt satellite dish, will save a beginner, if the search for a signal is unsuccessful, from unnecessary assumptions “is the antenna positioned correctly?” For example, if, when tuning, you deflect the antenna mirror to the top (or bottom) quite strongly. After all, you will already have a visual idea of ​​how it should stand, and in any case, you will return the mirror satellite dish to its original state, after which, continuing the search.

Although, of course, this will not get rid of manual settings, but still, it will significantly facilitate the whole process satellite dish settings(while also saving time).

Now let's calculate what slope the offset mirror will have satellite dish.

Satellite dish tilt - tilt angle calculation

Unfortunately, since the slope satellite dish, directly depends from her diameter and shape, in order to calculate this slope, alas... you need to do the calculation using special formulas.

I don't want to overload your head with already quite a lot of information. Therefore, here I will suggest three ways:

First way. Don't do any calculations now. When adjusting the vertical position of the antenna, first place it in a vertical position. Then, gradually lower the mirror down (or raise) until a signal from the satellite appears. In principle, this is what all experienced tuners do.

Second way. Pay attention to the angle of inclination satellite dishes installed in the neighborhood, for example, on the same house, or on the balconies and roofs of neighboring buildings.

Third way. To calculate the angle of inclination satellite dish To do this, use any computer program.

To make it more clear, to determine the tilt of the antenna, I will use the same program " Satellite Antenna Alignment".

To do this, launch this program and go to the “ Offset antenna"(Photo 1).

In the satellite selection window, select the one to which the . IN in this case, I chose the Express AM 22 satellite (Photo 2).

Photo 2 Select the satellite to which the transfer will be carried out setting up a satellite dish.

Let’s set the dimensions of your antenna mirror in the “Antenna width” and “Antenna height” cells (Photo 3).

Photo 3 Indicate the dimensions of the offset mirror satellite dish.

As soon as we enter the dimensions of the antenna, near the image below, the numerical indicator “ Antenna tilt required" will change its meaning. In my case it was 73.20° (Photo 4).

Photo 4 Tilt satellite dish.

Being at the antenna installation site, based on the fact that we will insert the initial position only visually, the tilt of the mirror satellite dish, it is easier to measure not from the horizontal, as is done in the program, but from the polar axis. To put it in more correct words, this will be the Declination angle - that is, the declination angle of the mirror satellite dish(Figure 1).

IN currently An unusual situation has arisen in the Ukrainian radio and television market: there are no cheap small-sized parabolic antennas. Imported parabolic antennas "pizza-size" ("pizza-sized", i.e. with a diameter of 20-40 cm) at the "electronic" flea market (Karavaevy Dachi) cost up to 15 USD. For this money, in a store or from a reputable company you can buy a much larger antenna - 0.6-0.8 m. The noticeable price also indicates the popularity of this product. Indeed, small antennas are used in MITRIS systems, modern systems Microwave television retransmission in big cities. Today MITRIS operates in Kyiv, Odessa, Lugansk, Zaporozhye, Chernivtsi, conquering more and more regional centers and their suburbs, and there is no doubt that it will be a serious competitor even to cable and satellite television. There is nothing to replace a small antenna: reception of MITRIS on a “bare” converter is often uncertain, and the use of antennas with a diameter of 0.6 m can give too high a signal level, creating mutual interference between channels.

So, the demand for small antennas is and will continue to grow. Why are there no antennas? Because their production is considered complex, even science-intensive, and it is focused exclusively on large enterprises that, unfortunately, specialize in producing only large batches of products. Where is the way out? It is obvious that the resulting niche in consumer demand can be filled by small enterprises. Equipped and working hard, a small number of specialists are able to provide cheap and quality antennas all of Ukraine. And if this has not happened so far, it is only because technical craftsmen are still shy of business, and businessmen are still timid of technology. In this article we will try to alleviate the plight of those who still decide to take on this matter by talking about the design and methods of constructing small-sized parabolic antennas and equipment for them.

Which parabolic antenna should I choose for broadcasting MITRIS type systems: offset or direct focus? Better - offset. In this antenna, the converter does not obscure the mirror, as in an axisymmetric one. With small antenna sizes, the shadow from the converter is commensurate with the mirror area, and this becomes significant drawback axisymmetric antennas. Their second serious drawback is the ability to accumulate snow in winter, which is not radiotransparent in the microwave. Even with a horizontal position of the main lobe of the radiation pattern (DP), the lower part of the mirror surface of an axisymmetric antenna is inclined at a positive angle to the vertical, which promotes snow sticking. Given the size of the antenna, very little snow is needed to cover half the mirror. If the main lobe of the offset antenna is located parallel to the horizon, then opening the mirrors “looks” at the ground, the angle between the opening plane and the vertical is negative, and snow does not stick. To be fair, it should be said that the plane of the plastic cover of the horn (waveguide) of the converter, which is installed on the offset antenna, is located at a positive angle to the vertical, but snow, as a rule, does not stick to the plastic.

So, we choose an offset mirror. Fig. 1 explains how the offset and axisymmetric mirrors are “cut out” from the primary paraboloid. This drawing is also necessary to understand how tooling should be designed and manufactured for production. The primary paraboloid is the surface of rotation of the parabola y=x2/4F, where F is the focal length. The parabola as a generatrix rotates around an axis, producing a paraboloid of revolution. The focal point is located on the y-axis at a distance F from the origin. A parabolic mirror of a satellite antenna is cut out of the primary paraboloid using a secant cylinder, the axis and generatrix of which are parallel to the y-axis of the primary paraboloid. If the secant cylinder is located symmetrically to the axis of the primary paraboloid, then an axisymmetric mirror is obtained. Typically, an offset mirror corresponds to a variant in which the generatrix of the secant cylinder coincides with the axis of the primary paraboloid. Then, as can be seen in Fig. 1, the axis of the paraboloid passes through the edge of the mirror. The focal point F and the direction to the perceived signal naturally remain unchanged, therefore, in the standard location at the MITRIS repeater, the opening of the offset antenna will “look” at the ground. An offset antenna resembles a cross-eyed person: it seems to us that it is “looking” in the wrong direction. The direction of maximum reception at the offset antenna almost coincides with the console that holds the converter. The diameter of the secant cylinder will be the diameter of the axisymmetric mirror and the minor axis of the ellipse of the opening of the offset mirror. This minor axis is also called the “conventional diameter” of the offset mirror: from the side of the satellite or the MITRIS microwave repeater, the offset mirror appears as a circle with the diameter of a secant cylinder. If you look straight at the opening, you will get an ellipse: it is formed by the line of intersection of the paraboloid of rotation and the cylinder parallel to the axis of rotation.

Considering further Fig. 1, it is appropriate to discuss the question of where the axis of the converter, which is installed at the focus F, should be directed: if the mirror were direct-focus, the converter would obviously be oriented towards the bottom of this mirror to the origin of coordinates, therefore to offset it should “look” along the bisector of the opening angle, i.e. the angle at which the offset mirror is visible from focus F. However, there is one caveat. The offset mirror is “illuminated” by the radio wave unevenly: the radio flux density is greater near the origin of coordinates and somewhat less at the edge of the offset distant from it - this is affected by the change in the angle of inclination of the surface to the radiation flux. The lower part of the offset is the most “loaded” with radiation and, accordingly, it re-radiates the most energy into the converter. I would like to make this comparison: in the spring, snow melts much faster on the slopes of ravines, which sunlight falls almost perpendicular to their surface, and where the radiation density is greatest. Because of this, the “aiming point”, i.e. The place on the mirror where the converter axis is directed is moved slightly below the sight along a bisector.

Now it's time to select the initial offset parameters. I propose to take the conventional offset diameter as 33 cm. This will be a large pizza! If your requests differ from mine, then, following the calculations below, you can design a different “pizza”. So, D = 33 cm. When choosing focus F, we should remember that here the range of our “arbitrariness” is already small, since we are limited by the F/D ratio: in order for the converter to “see” the entire offset well, the F/D ratio must be quite large , for example, 0.5-0.6. This value is traditional for offsets (offsets are long-focus), while direct-focus antennas are characterized by a different F/D ratio - 0.3.0.4. We choose a ratio of 0.5. Then F = 16.5 cm. We immediately calculate the aperture angles: the angle to the major axis of the opening ellipse from the focal point arctg(4FD/(4F2-D2))=90°, and the angle to the minor axis of the opening ellipse (to the conventional diameter of the offset 33 cm) 2arctg((0.5D/[(0.5D)2+(F-D2/8F)2]1/2)=83.6°.

As you can see, these angles are almost the same because the offset mirror has a long focal length. The offsets fit perfectly with the classic converter horns designed for this type of mirror. Such horns are a cone with a solid angle of 45°, the width of the main lobe of its DP at the 1/2 power level is 80-90°. I will note one important detail: the area of ​​maximum sensitivity of the converter is directed forward to the middle of the mirror. The converter “sees” the edges of the mirror worse, and the effective area of ​​the mirror creating the radiation flux perceived by the converter is only about 0.6 of the total opening area. This parameter q=0.6 is called the surface utilization factor. Now we proceed to determine other design and analytical characteristics of our antenna. Major axis of the opening ellipse B = D(16F2 + D2)/4F = 36.9 cm. The maximum depth of the mirror, measured from the opening plane to the paraboloid, H = 0.25D2/(16F2 + D2) = 3.7 cm. These characteristics will be required to preliminary estimate the metal consumption for the production of the mirror and the manufacture of equipment. The offset mirror has a symmetrical elliptical opening and an asymmetrical profile: in the lower part on the side of the fixed converter it gains depth faster. The angle between the tangent to the generatrix of the paraboloid and the major axis of the opening ellipse at the bottom and top of the mirror is respectively: arctg(D/4F) = 26.6° and arctg(D/2F) - arctg(D/4F) = 18.4°. For this reason, the maximum depth point is located closer to the bottom of the offset. The difference between these angles is only 8.2°, and this small value will be the only indicator of the correct orientation of the mirror in the “top-bottom” direction, so design and technological measures will be required to ensure that this orientation is never lost during the production and assembly of mirrors.

Let's determine the expected gain of our antenna. Mirror gain parabolic antenna strongly depends on the wavelength of radio emission, so the operating range of frequencies and wavelengths should be selected. Kiev MITRIS operates in the range of 11.7-12.5 GHz, so we will assume that the characteristic frequency of the operating range is f = 12 GHz, and the characteristic wavelength is 2.5 cm. The calculated gain of an ideal antenna with a diameter of 33 cm is G = 20lg(nDq1/ 2/l)=30.1 dB.

I note that an ideal antenna, i.e. an antenna whose gain corresponds to the calculated one must have a deviation from parabolicity of no more than 1/32 = 0.8 mm. Manufacturers know that this is a fairly stringent requirement, but on small diameters it can be achieved without big problems. The next quality class is a deviation of no more than 1.6 mm. It is quite easy to meet this ratio even with large mirror diameters, but the antenna gain with this ratio will already be slightly lower than the calculated one. Since the antenna gain includes the surface utilization factor q, the gain is, as it were, tied to the horn that uses the mirror for irradiation during transmission and for perception of the radio wave during reception with a standard value of the parameter q = 0.6.

Therefore, amplification of a satellite dish is a kind of “thing in itself”. Specialized irradiators selected for different F/D ratios are stored at equipped test sites. It is unlikely that a small enterprise producing “pizza-size” antennas should have such a testing ground. The author’s opinion as an “old antenna guy” is this: all satellite antennas for domestic use, designed for the use of arbitrary feeds, should only be metal structures, in which the manufacturer guarantees only the correct shape of the mirror. For an individual parabolic antenna, only the correct geometry is important, that’s all. Experienced manufacturers know what we are talking about.

Next, we will design a measuring triangle for our antenna. Of course, it will not be needed now, but in production, but its design will add information and confidence to you in the ownership of your antenna. Fig. 2 shows the appearance of the measuring triangle and helps to understand its function. The measuring triangle will help you always accurately find the focus of your “plate” and the position of the converter. Sides of this triangle a,b,c calculated as follows:

a = B = 36.9 cm;

b = F+D2/4F = 33 cm;

c = F = 16.5 cm.

In practice, you can make the lower side a together with a frame, the curved part of which forms a paraboloid, i.e. parabola. This combination is convenient because the installation of the triangle on the mirror will always be unambiguous, and the sharp corners at the ends of side a will not scratch the painted surface. In fact, the measuring triangle can be further improved. After adding the parabolic frame, side a can be extended a little; it will lie on the mirror flange, which will make the triangle more convenient. From the focal point, an aiming direction should be drawn to orient the converter. It has already been mentioned that the angle bisector bFc is not entirely suitable for this purpose. It is better to orient the converter to the point of maximum depth of the mirror. It is located at the intersection of the axis of the generating cylinder with the paraboloid.

This point is very easy to find, and the accuracy of its determination will be even higher if you do not measure the maximum depth at all, but proceed as follows: divide side b, equal to the conditional diameter of 33 cm, in half and from its middle parallel to the axis of the paraboloid, i.e. parallel to side c of the triangle, draw a straight line; it intersects the paraboloid at point P. This point is the point of maximum depth, and we select it as the aiming point, and the converter axis should be located on straight line PF. The PF line can be highlighted with paint, but it is even better to attach a removable cylindrical mandrel to it, which should fit into the suspension clamp designed to secure the converter. The diameter of this mandrel should be 40 mm, this is already an established standard for converters. There is no other neck diameter for offset converters. But another important connecting dimension of converters - the distance from the neck to the end of the horn (plastic cap) has not yet been formed. Most often, the geometry of the converter corresponds to the dimensions shown in Fig. 3.

Converters from Gardiner, Cambridge, FTE, Strong and others now have this or approximately this geometry. The focal point should be located slightly deeper than the cap (i.e. inside the converter horn) at approximately W4 = 6 mm. Therefore, the sharp vertex F of the measuring triangle can be cut off by this small amount or, if a mandrel is made that imitates a converter, the mandrel can be moved closer to the mirror. This last procedure almost completes work on the triangle. Why "almost"? Because there is also the effect of underpressing the mirror, which slightly moves the focus away.

Looking ahead, let's say this: if under-pressing of mirrors, measured as incomplete maximum mirror depth that does not correspond to the calculation, has become a mass phenomenon, then I recommend moving the converter mounting clamp due to the actual distance of the focal point. This distance in this case can be calculated using the formula: 5F = -4.55H, where 5H is the difference between the calculated and actual maximum depth of the mirror; 5F - change the focal length. There is a minus sign in the formula because a decrease in the depth of the mirror corresponds to an increase in focal length.

Let's start designing the equipment. To do this, we must know which pressing technology we can focus on. Usually mirrors are medium in size, i.e. from 0.6 to 2.2 m are pressed using pneumatic or hydraulic pressure: a thin-sheet aluminum or steel billet is hermetically pressed around the perimeter (along the contour) between the matrix and the lid, then compressed air or water under pressure of several atmospheres is released under the lid, and the workpiece stretches out, pressing into the matrix and acquiring its parabolic shape. The workpiece must be made of plastic material, for example, aluminum grade A5, A6 or steel grade 08KP. Known alternative technologies production of mirrors: axisymmetric mirrors can be rolled out by sequentially pressing the workpiece with a roller, clamped at the top of the punch. The punch is mounted on a rotary machine and rotated, while the roller remains stationary. An axisymmetric mirror of a small standard size can be rolled out on a lathe. Large antennas, for example from 3 to 5 m or more, are made from petals, collecting them on a slipway. The petals themselves are made on a stretch press, pulling the workpiece onto a parabolic block. A unique explosion pressing technology is also known: first, the mirror is pressed by hydrostatic pressure of water, and then a small charge is exploded in the water, and the blast wave perfectly presses the mirror made of elastic alloys, for example, AMC-M. This provides additional qualities of such mirrors: they are durable, accurate and lightweight. Recently, cast (lost wax) pizza mirrors have appeared on the market. Perhaps you have some other new technology? Go for it!

This article describes the design and methods of designing small parabolic antennas and equipment for them. The beginning of the article is in the previous issue of the magazine.

Small mirrors can be pressed in the classic way, for example, pneumatic pressure, while measuring the amount of pressure with the thickness of the metal and the dimensions of the mirror: pressure is proportional to the thickness of the metal and the length of the contour (perimeter) of the workpiece and inversely proportional to the area of ​​the workpiece. The perimeter length L and the area of ​​the elliptical workpiece S are related by the relation

Therefore, pressure P, metal thickness and perimeter length L (or average diameter) are related by the similarity relation P-Ld/S-d/L-d/D^.

The average and nominal diameters are close, and for estimation calculations their difference can be neglected. It is known that an offset mirror with a nominal diameter of 0.9 m from a steel billet 08KP with a thickness d = 0.8 mm can be reliably pressed at a pressure of 6 atm. What air pressure will be required to press a mirror with a nominal diameter of 0.33 m from a steel sheet 0.5 mm thick?

Answer: P = 6.0.9.0.5/ /(0.8.0.33) = 10 atm.

If your compressor and the quality of the workpiece crimp can cope with this pressure, then you will not have problems. You can switch to a thinner sheet if problems arise, but not thinner than 0.35 mm (for steel): the strength of the mirror and the durability of your pizza antenna will decrease.

There is a radically different method of pressing - drawing. This is how the dishes are pressed: the workpiece is crimped along the contour, and the shaping is carried out by the lid, transformed into a movable punch, which slides onto the clamped sheet of metal and pulls it towards itself. The metal takes the form of a punch. No pneumatics or hydraulics are required, but the press must be two-way (crimping plus wrapping). In addition, the problem is the wear of the punch: if for pressing dishes the wear of the punch is not critical, then for the production of mirrors it is important. A worn punch should be repaired or replaced. There is practically no wear of the forming matrix during blow pressing; this is an “eternal” equipment. A small hydraulic press with a pressing force of several tens of tons required for flanging the mirror and clamping the workpiece sheet while inflating the mirror is ideal for this method. For drawing, a two-pass mechanical or hydraulic press with approximately the same pressing force is required. To draw our mirror, a small force PS = 10 tons will be required. Flanging, depending on its design, will require the same 10-20 tons. These forces are determined by the cross-sectional area of ​​the drawn metal.

How to make equipment? I would not like to go into details, if only because the equipment is structurally tied to specific presses, to the technological traditions of the press section and the capabilities of tool production. I would like to draw your attention more to specific requirements to the equipment, the main thing of which is taking into account the thickness sheet material. If you use the inflation method, then the forming matrix should not have a parabolic profile, but an equidistant paraboloid; its surface should move away from the paraboloid of rotation by the thickness of the metal being pressed. If you hope to use two types of material of different thicknesses (aluminum and steel), then you can bore the matrix to an equidistant of the average thickness of the metal, for example, if an aluminum sheet has 5 = 1 mm, and a steel sheet has 5 = 0.5 mm, then we select the equidistant with 5=0.75 mm. Boring of the matrix (and the punch too) is usually carried out on a CNC rotary machine. The technologist-programmer must enter a program, the compilation of which requires a tabular or analytical specification of the trajectory of the tip of the cutter. If equidistance is not taken into account, i.e. if we neglect the thickness of the sheet material, then the programmer needs to set the parabolic generatrix y=x2/4F.

Taking into account the thickness will give the following analytical function

y=x2^ + d - d((x/2F)2+1)1/2, where the origin is chosen on the surface of the matrix.

Figures 4 and 5 show the process of manufacturing a matrix and a punch from forgings. The carousel rotates around the y axis. Both the matrix and the punch of a pizza mirror can be bored not according to a program, but according to a template, which is pre-made by a careful toolmaker. Making a paraboloid surface is a complex operation, but that's only half the battle. After this operation, the matrix is ​​sent to a CNC coordinate milling machine for boring the flanging profile. The lid should be made on the same machine. If you chose the method of drawing a mirror and bored a paraboloid on a punch on a rotary machine, then after that it can be reinstalled on the same machine and bored into a cylinder with an outer diameter of 33 cm. It will fit into the mandrel where the sheet of metal intended for drawing is clamped exactly like a cylinder, despite the fact that in the opening it is a strict ellipse. Entry angle a=arctg(D/4F)= arctg 0.5=27°.

If this story seemed too complicated to you, don’t be embarrassed and try to do the calculations yourself or make a model of the equipment from a piece of plasticine. Note that modern parabolic antenna designs sometimes assume a circular aperture rather than an elliptical one, or limit the aperture ellipse to a square, or slightly flatten the ellipse by limiting its width or height. The complexity of designing and manufacturing equipment then increases enormously. It should be noted that the radio engineering properties of the mirror also deteriorate.

Now let's discuss the suspension and converter holder devices. If you want to make a plastic converter holder (clamp), be sure to choose a material with high guaranteed climate resistance. The converter weighs up to a kilogram and costs a lot of money. Destruction of the holder during its service life (10-15 years) must be completely prevented. If the converter holder assembly is mounted on a mirror, it will be economical and reliable, but less aesthetically pleasing than a cantilever holder mounted on a suspension behind the mirror.

The antenna suspension must ensure its adjustment in azimuth and elevation and fixation in the selected direction. It is very important that the range of movement of the mirror in declination angle complies with operating standards: the axis of the paraboloid must be directed along the surface if the antenna is intended for MITRIS. If you intend to use an antenna to receive satellite TV, then the range of movement of the axis relative to the horizon, i.e. in elevation, should be increased. The elevation angle of the vertex satellite depends on the latitude of the area in accordance with the formula φ = arctg((cos^-0.1511)/sin^), where φ is the angle of latitude of the area. The suspension design should allow for angle variation to benefit all buyers. Please note that the antenna adjustment for elevation must be done from a vertical support, for example, from a long vertical pipe. It’s good if you consider this requirement obvious, but it is not obvious to everyone. You've probably seen Polish MABO antennas, beautiful in all other senses, frozen on our roofs in the most exotic poses. They do not allow the beam to be aligned parallel to the Earth's surface if the antenna is mounted on a long vertical pipe.

The suspension unit must be simple and reliable. When you make a mock-up or prototype of an antenna, do not forget to invite an experienced antenna engineer: he will make the right conclusion regarding the success of the suspension design. Choose a material for the suspension that is thicker and stiffer than for the mirror; if you like stamping, then this material will also be reinforced with zigs, and you need to make sure that the rigid mounting tabs are tangent to the mirror at the point of their connection, otherwise deformation of the mirror is inevitable: the appearance is lost and the reinforcement deteriorates. Unfortunately, the products of many companies have this obvious drawback. The tangency of the legs on a small antenna can be selected practically, but this must be carefully done in the documentation and executed in the equipment. If the antenna is larger than a pizza, then it is better to first calculate the geometry of the legs.

Imagine that on big table we drew a rectangular coordinate grid(x^) and placed our mirror on it with the opening down, and placed it so that the x1 axis coincides with the major axis of the opening ellipse, and the point x1=z1=0 falls on the beginning of the major axis in the lower part of the opening. We will assume that the y1 axis is directed upward; it will be the height scale on the parabolic surface. This situation is depicted in Fig. 6. Let's assume that the antenna suspension contains four legs and you need to determine their inclination to the table plane. Since the paraboloid is curvilinear, for each attachment point it is necessary to either specify two angles - along the x1 axis and along the z1 axis, or indicate the direction of the greatest curvature and give the angle of inclination in this direction. The paraboloid is symmetrical about the x1 axis, so it is enough to solve the problem for two points A and B. We will work out the method for calculating angles using the example of point (hole) A. This method is entirely based on calculating the height y1. To calculate the height of point A above the table surface, you should use two formulas y1=(Dt-t2-z12)(16F2+D2)-1/2, where the auxiliary parameter t is defined as t= -8F2/D+1/2. These formulas are given in general form so that you can use them whenever you want. In the case of our antenna, F=16.5 cm and D=33 cm, so the formulas are simplified: y1=(33t-t2-z12)/73.8; t= -66+(43.56+147.6x1-z12)1/2. We can only hope that the numerous formulas did not strain your memory too much with concepts from analytical geometry and mathematical analysis. Let them finally work for small businesses! In conclusion, I would like to remind you of what you already know: honor must be protected from a young age, and quality - from the first samples. Raise the quality bar as high as possible and hold it with all your might, because provocations to a drop in quality will arise every day. Biggest problems arise regarding the quality of paint and varnish and galvanic coatings. Preparation of the mirror surface for painting should be better than “technologically”. Of course, you need to take care of painted parts during transportation and storage. This is your problem, not the buyer's, since the damaged appearance of the antennas can ruin your reputation. If you can do electroplating somewhere in the defense industry, then you are lucky. If you do hot-dip galvanizing, you will bypass all competitors. In order not to forget about your competitors, hang a Polish MABO on your site, for example, with a diameter of 0.6 m offset (it is small), and next to it your antenna and look at this couple every day through the eyes of a buyer.

M.B. Loshchinin, Kyiv

At this stage, we need to determine the approximate tilt of the mirror of our satellite dish in a vertical plane.

You can, of course, not calculate this parameter. But, knowing the correct tilt of the satellite dish will save a beginner, if the search for a signal is unsuccessful, from unnecessary assumptions." Is the antenna positioned correctly?? ". For example, if, when setting up, you deflect the antenna mirror quite strongly to the top (or to the bottom). After all, you will already have a visual idea of ​​how it should stand, and in any case, you will return satellite dish mirror to its original state, after which, continuing the search.

Although, of course, this will not eliminate manual configuration, it will still significantly facilitate the entire process. satellite dish settings(while also saving time).

Now let's calculate what slope the offset mirror will have satellite dish.

Satellite dish tilt - tilt angle calculation

Unfortunately, since satellite dish tilt, directly depends on its diameter and shape, in order to calculate this slope, alas... it is necessary to make calculations using special formulas.

I don't want to overload your head with already quite a lot of information. Therefore, here I will suggest three ways:

First way. Don't do any calculations now. When adjusting the vertical position of the antenna, first place it in a vertical position. Then, gradually lower the mirror down (or raise) until a signal from the satellite appears. In principle, this is what all experienced tuners do.

Second way. Emphasize on tilt angle of satellite dishes installed nearby, for example, on the same house, or on the balconies and roofs of neighboring buildings.

Third way. To do calculating the tilt angle of a satellite dish To do this, use any computer program.

To make it more clear, to determine the tilt of the antenna, I will use the same program “Satellite Antenna Alignment”.

To do this, launch this program and go to the “ Offset antenna».

Determining the tilt of a satellite dish.

In the satellite selection window, select the one for which the satellite dish will be configured. In this case, I chose the Express AM 22 satellite (Photo 2).

Photo 2. We select the satellite for which the satellite dish will be configured.

Let’s set the dimensions of your antenna mirror in the “Antenna width” and “Antenna height” cells.

We indicate the dimensions of the offset mirror of the satellite dish.

As soon as we enter the dimensions of the antenna, next to the image below, the numerical indicator “Antenna tilt required” will change its value. In my case it was 73.20°.

Satellite dish tilt.

Being at the antenna installation site, based on the fact that we will insert the initial position only visually, it is easier to measure the tilt of the satellite antenna mirror not from the horizontal, as is done in the program, but from the vertical. To put it in more correct words, this will be the Declination angle - that is, the declination angle of the satellite dish mirror.

Satellite dish tilt, or declination angle.

Therefore, to make it more convenient for us, we will do some simple calculations. Since a right angle is 90° degrees:

That is, if we place the satellite dish strictly vertically, then from this position the antenna mirror must be tilted by 16.80 degrees.

In principle, since we will be setting up the satellite dish manually (without any “special tools”), we don’t need such precision. Therefore, take a sheet of paper, draw this angle, and just visually remember its slope.

It turns out... to start setting up a satellite dish for the Express AM 22 satellite, you must initially place it at 16.80° from the vertical position. These meanings naturally apply specifically to my case. Do the calculations for your option, and just remember these two parameters.

No matter what accurate data the Satellite Antenna Alignmen program gives us, we will not be able to take full advantage of this accuracy, since we seem to have nothing to bind to for measurement. After all, we will only have to imagine all the planes needed for counting, and this means that we will measure degrees only in our thoughts, with our internal “degree meter”. But all this is quite enough for our purposes.

And so, we know the coverage area of ​​the chain of satellites visible from the installation site of the satellite dish, and the vertical tilt of the antenna mirror is also known to us. You can basically start preparing satellite equipment. But before that, let's digress a little. I would like to explain some points regarding the vertical adjustment of a satellite dish, which you may also encounter.

Satellite dish tilt - setting

(description of some points related to the vertical alignment of the satellite dish)

In the design of a satellite antenna, the suspension is designed in such a way that the antenna mirror can be equally raised or lowered to the same maximum angle

Satellite dish suspension with equal vertical rotation angle.

But in my practice, I have come across satellite antenna hangers, in the design of which the vertical rotation of the antenna itself was carried out as if tilted to one side. Therefore, with such a design, it is important to assemble it correctly, in accordance with your geographical location, or more precisely, depending on your latitude and the distance of the satellite.

Since I am at a latitude of 63°, the tilt of the satellite dish will be 16.80° from the vertical, and if you mount an antenna with a suspension with a priority tilt in one direction, then you need to place a U-shaped element as in Photo 2 (it shown by red arrow).

At the same time, the angle of travel of the satellite dish mirror just fits into the tilt of “16.80°” (Fig. 1). In this case, it feels as if the antenna itself is looking slightly toward the ground.

If my location were closer to the equator, for example, at 40 degrees north latitude, then in this case, the satellite dish mirror will rise, and the angle of travel should be as in Fig. 2.

In this case, the U-shaped element must be positioned in reverse, as in Photo 3 (here I apologize, I simply turned this photo vertically).

The next point also concerns adjusting the tilt of the satellite dish, or rather, installing the suspension with a slope in one direction, on a vertical support.

When using a satellite dish hanger with a priority slope in one direction, if your location is more distant from the equator, it must be installed on a mount, as in Photo 4 and Photo 5.

Satellite dish, the suspension of which is inclined in one direction

Installed satellite dish.

Since in this case, the satellite dish will have a certain angle of inclination towards the bottom. Therefore, the L-shaped suspension element, at one end of which the converter is fixed, needs to have some free space, allowing you to change this antenna tilt angle.

To more clearly explain the essence of this problem, which you may also encounter, let’s try to mentally install the already configured satellite dish shown in Photo 4 on a vertical support (Photo 6 and Photo 7).

Homemade vertical satellite tower

Homemade vertical support for installing a satellite dish on a horizontal surface.

Comparing these two images (Photo 8), we will see that the corner of the L-shaped suspension element (Photo 9) rests against the wall of the vertical pipe, and the place where the suspension is fastened does not even reach this pipe.

Naturally, if we nevertheless secure this suspension, pulling it to the pipe itself, the angle of inclination of the satellite dish will change, thereby making further vertical adjustment impossible.

Of course, this option for installing such a suspension, shown on Photo 7, on a vertical support, is quite suitable for those whose antenna mirror will stand almost vertically, or higher. For others, when purchasing a satellite dish, you will have to take into account the problem described above.

Since the satellite antenna itself, as a rule, comes with its own standard suspension, it is better to purchase a support for it, depending on the coordinates of the place where this antenna will be installed.

Based on this, when purchasing a satellite dish and support, it is advisable to already know the tilt angle of the antenna for your area, or rather, the range of this tilt angle.

To find out the tilt range of the satellite dish, let's again use the Satellite Antenna Alignment program. As always, I will explain based on my own example.

Equipment for setting up a satellite dish

The satellite dish is in place, connectors are installed on the cable, and all preliminary settings have been made in the receiver. In order for us to be able to make further adjustments, it is necessary to have free access to the back of the already suspended satellite dish.

To position the satellite dish to the selected satellite, we will need the following equipment for setup:

• 1. A small or portable TV that supports the outputs that are on your receiver.

3. Segment coaxial cable, to connect the receiver to the converter, approximately 1.5...2 meters long, with connector connectors installed at both ends (this cable is used only during setup).

• 4. Connecting cable (LF or HF) corresponding to the connection between the satellite receiver and TV.
• 5. Wrenches and screwdrivers suitable for fastening the converter and satellite dish mounting.

If you don’t have a small portable TV, then, of course, there is no point in buying it specifically for setting up a satellite dish. To avoid unnecessary costs, you can purchase a relatively inexpensive device called "Sat Finder". It was created specifically for setting up satellite dishes at home. At the time of writing this page, the cost of such a device was in the range of 400...700 rubles, which is significantly cheaper compared to the cost of a portable TV. It, of course, has its advantages, and unfortunately, it also has its disadvantages. You can read about what kind of device this is and how to work with it. If this is your first time setting up a satellite dish, then I would still recommend that you use the option with a receiver and a portable TV. I think this will be easier and more reliable for you.

Based on the fact that I will explain the installation and configuration of a satellite dish using my own example, I will use the following equipment and tools:

Digital satellite receiver (in this case, an FTA receiver designed for viewing open channels is suitable for us).

Looking at back panel, you can see that this receiver can be connected to a TV, both at high frequency, from the output of the RF modulator, and at low frequency, through tulip-type audio-video connectors.

Portable TV. In principle, any TV will do here. small sizes. The main thing is that it supports the outputs that are present on your satellite receiver.
Looking at the back panel this TV, you can see that it can also be connected via both a high-frequency input and a low-frequency audio-video input.

If you have a receiver with an HF modulator, then there is no need for low-frequency audio-video connectors, but in this case, the TV must support the UHF radio frequency range (although I do not rule out the possibility that the HF modulators of some receivers, or older model TVs, can only operate in the meter wave range, in the microwave range).
If you have a receiver without an RF modulator, then low-frequency audio-video connectors on the TV itself are required.

A piece of coaxial cable(for connection to the converter), approximately 1.5...2 meters long, and with “connector connectors” installed on this cable at both ends.

LF (low frequency) audio-video cable tulip type, for connecting to a TV via low-frequency output and input.

Radio frequency cable (RF), another name for high frequency cable (HF). For the option of connecting to a TV via radio frequency antenna input(only if the receiver has an RF modulator).

Due to the presence of an audio-video input on the TV, I will not use this cable.

Wrenches and screwdrivers, for tightening the suspension fasteners and converter fastenings corresponding to your satellite dish kit.
Also, to tighten the connector connector on the satellite converter, you will need an 11-size open-end wrench.

And so, the equipment for setting up the satellite dish and the tool are prepared. Finally, we will need some network extender to bring it to the setting location (to an already installed satellite dish), mains voltage 220 volts. The extension cord must have two sockets for connecting a satellite receiver and a portable TV.

Also, to configure the satellite dish in the horizontal plane, we will need compass.

Connecting equipment for setting up a satellite dish

Now, you can move the tuning equipment and tools to the installation site of the satellite dish. General scheme connection of equipment for subsequent configuration is shown in Fig. 1.

Rice. 1 General diagram of connecting equipment for setting up a satellite dish.

For convenience, I placed the satellite receiver with TV on a small chair (Photo 1). It is advisable to position the TV itself so that when setting up a satellite dish, you can adjust the direction of its mirror with your hands and look at the TV screen, almost simultaneously.

Photo 1 Connected equipment for setting up a satellite dish.

At the time when the photographs for this page were taken, it was the beginning of winter. Therefore, the temperature outside reached minus 7...10 degrees. In such conditions, it is not advisable to use electronic devices, which are intended to be used at room temperature. But this means that setting up the satellite dish will have to be postponed to a warmer time, which, of course, did not suit me. So I continued with this setup anyway, but... following some rules, and these are:

1. As soon as the equipment is outside, you must immediately supply power to it. This means that you need to not only turn it on, but also take it out of standby mode (take it out of the “standby” mode by pressing the “Power” button, for example, on remote control), that is, bring it into full working mode. This is necessary so that the radio elements of the equipment are heated due to their own thermal radiation. For optimal performance apparatus, such heating, of course, is not enough, but this will not allow it to cool quickly enough.

2. If, in any case, the device was moved back into the heat, before turning it on, you must wait at least 30...40 minutes at room temperature. This also applies to taking it back outside if necessary.

3. It is not advisable to adjust the satellite dish at temperatures below 10..12 degrees.

4. Carry out adjustment work as quickly as possible.

5. If the satellite receiver begins to react poorly to any commands, freezes, or behaves in some other unusual way. Turn it off immediately and bring it into a warm room for 30...40 minutes. And only after that, continue any work with it.

Although, according to to a greater extent, I would certainly not recommend operating the equipment in such extreme conditions for it. In any case, you will do this at your own responsibility, that is, at your own peril and risk.

When installing satellite equipment in the cold season, it is strongly recommended: the entire setup electronic equipment, which can be carried out without being near the satellite dish structure (for example, pre-setting receiver), carry out it in a warm room, and only after that transfer it to the very place where the satellite dish is installed and configured.

As for the satellite converter itself, it was initially designed by the manufacturer to operate in both normal and low temperature conditions (but I do not exclude that there are models of converters designed to operate in hot countries). The only thing I want to warn you is that if the satellite converter was moved back into the heat, before putting it back into the cold, it is also advisable to wait at least 30...40 minutes....

Now, let's connect the setup coaxial cable, with the connectors installed on it, to the receiver and converter (Photo 2 and Photo 3). Position it so that, if possible, it does not interfere with various manipulations with the satellite dish. When you screw the connector-connector, do it only by hand, since this cable is only a setup cable, then, when you connect the permanent one, tighten the connector with a wrench (usually an 11 wrench), but do not overdo it, even though it is metal, , quite fragile.

Connecting a cable to set up a satellite dish.

Coaxial cable connection

Connecting the coaxial cable to the receiver.

Connecting a coaxial cable to a satellite dish converter.

Connecting a satellite receiver to a TV

Connect the satellite receiver and portable TV (Photo 4). If your TV does not have a low-frequency input, then connect via. But as I already mentioned, for this the receiver must have an RF modulator. Also, in this case, you need to configure your TV to the radio signal coming from the receiver. The principle of setting up the TV itself will be the same as when receiving broadcast programs, the only difference is that instead of terrestrial antenna You will connect the RF cable coming from the satellite receiver.

Photo 4. Connecting the receiver to the TV.

Connecting the receiver to the TV to set up a satellite dish via a low-frequency tulip audio-video cable.

Connecting the receiver to the TV to set up a satellite dish via a coaxial high-frequency (radio frequency) cable.

Below on Photo 5, it is indicated which main connectors may be needed for connection.

Photo 5. Connectors for connecting a satellite dish and TV.

Connect the power plugs of the TV and satellite receiver to the extension cord, and also turn on both devices in mode full inclusion. If they are connected via an audio-video cable, then switch the TV to receive a video signal (A/V mode); if via an RF modulator, tune your portable TV to the modulator frequency (it is better to do this in advance, in a warm room). In general, ensure that the TV screen displays a stable image transmitted from the satellite receiver.

Setting up a satellite dish for a satellite

Press the button on the receiver Menu", and go to the submenu for editing transponders. Select the satellite of interest, and just in case, check the parameters of the desired transponder(s), which we entered earlier.

Also, if desired, here you can immediately edit the name of this satellite. It should be noted that usually in names you can enter only a certain number of letters, so if the word does not fit, you have to shorten it. I usually try to write the name of the satellite and its position in degrees. Since the number of letters is limited, I abbreviated the satellite “Express AM 22” 53°E as “Exp 22-53”. In principle, the function of renaming satellites is made only for convenience, and there is no special need for it (i.e. the name of the satellite is not on any important parameter, does not affect). But, if in the future you plan to install a motor on a satellite dish, knowing the name and position of the satellite, it will be easier to navigate when choosing television and radio channels.

Your transponder editing menu may differ significantly from the option I propose, but the basic principle will remain unchanged.

Now let's take a look at the transponder editing menu in more detail, using receiver No. 1 as an example. Such a menu will be our main tool in subsequent setting up a satellite dish for a satellite(Photo 1).

On previous pages, to reduce page download time, I had to crop all the “menu” images, showing only those necessary on this moment, plots. Now, let's look at it in full. In the image, I have highlighted two areas needed for subsequent setup of the satellite dish.

Photo 1. Menu for editing satellite transponders and signal indicator.

In the first section, there are parameters of one of the transponders of the selected satellite. Namely: frequency, symbol rate, and type of polarization. If necessary, we can adjust these parameters.

In the second section, an indicator of signal level and quality is displayed. This indicator usually has two indicators, calculated as a percentage (%). One indicates its level, may also be designated as - Strength, Level, L, etc. Other, displays quality of this signal may also be designated as - Quality, Q, etc. Based on this indicator of signal level and quality, we will “catch” the satellite we need.

Each satellite receiver, of course, has its own original interface that displays the appearance of such an indicator. But, in their principle, they are very similar. To make it easier for you to understand how this indicator will look in your receiver, let's look at three of their options.

In receiver No. 1, the satellite signal indicator appears only when there is a signal at the receiver input that matches the transponder parameters, as evidenced by yellow stripes (Photo 2 and Photo 3). That is, it seems to have two states: there is no signal, or its presence, which is usually displayed as a percentage.

Receiver No. 2 has three satellite signal indicator states. The first state (Photo 4) shows the absence of a signal. The second (Photo 5) shows that this signal is there, but the parameters do not correspond to the selected transponder (possibly satellite antenna already configured, but to a different satellite), in this state, the signal strength indicator turns red.

Well, the third state of the indicator satellite signal(Photo 6), shows the presence of this signal, while changing the length and color of the stripes of the indicator itself.

Photo 6 There is a signal.

The third type of indicator of the presence of a signal from a satellite, I took, at that time, from the well-known satellite receiver "DRE 4000" (or DRE 5000). Such a receiver allows you to view the program package of the Russian project, Tricolor-TV, which is broadcast in DRE encoding Crypt (DRE crypt). With this satellite receiver, instead of stripes (as in previous versions), the signal is displayed in the form of dots (Photo 7 and Photo 8).

The greater the number of points of such an indicator, and, accordingly, the percentage value, the better the signal characteristics from a given satellite (from a given transponder of this satellite) will be.

Now, I hope you can figure out your indicator without any problems.

And so, the current transponder has been entered, you can move on to the mechanical part of setting up the satellite dish. In principle, judging by this, this is precisely why this entire section was created.

Satellite tuning

At this stage, let's remember what we did when we determined the horizontal direction to the selected satellite, and repeat these steps, but apply this to the satellite dish setup itself. That is, at this stage, we will first align the mirror of our satellite dish in a given direction (in the direction of the selected satellite).

Preliminary horizontal adjustment of the satellite dish

Taking the compass in hand, from the installation site of the satellite dish, we will determine again, based on the azimuth, the direction to the selected satellite (Fig. 1).

Rice. 1. Determining the azimuth of the direction to the satellite.

Let's set the compass sight in accordance with the azimuth of the selected satellite. Looking through this sight, we will find a landmark on the surface of the earth, which is located in the same direction as the satellite itself.

That is, the direction of the mirror plane of the satellite antenna of the landmark and the satellite will be on the same line.

Selecting a landmark- as a landmark, you can take a tree located on the ground, an electric pole, a house window, and so on... This landmark will be for us, like a beacon, in the direction of which we will initially align the plane of the satellite dish mirror along the horizon (Fig. .2).

Rice. 2. Aligning a satellite dish to a satellite using a landmark.

The presence of a landmark will make it much easier for you to search for a signal from a satellite, without allowing us to move the satellite antenna mirror in the wrong direction. It is more convenient to look at the landmark itself at the bottom of the antenna structure itself, along the L-shaped converter holder (as if aiming) .

Alas, no matter how hard we try, it is practically impossible to immediately install a satellite dish strictly in accordance with the azimuth (although in practice, this has happened). Therefore, our next task will be to expand the range of the expected location of the satellite.

Let's take this option as an example. There are two houses located not far from each other, and the landmark will be a tree standing almost between them (Fig. 3).

Rice. 3. Setting the direction of the satellite dish, choosing a landmark.

The picture shows, let's say, the ideal option. In practice, of course, all this can be completely different, but, for example, I think this option will be enough

Since we have determined only the approximate direction to the satellite, and we cannot say that our landmark is exactly on the same vertical line with the satellite itself, we will have to slightly expand the search range (Fig. 4).

Rice. 4.

That is, we need to minimally expand the search range, but at the same time, be sure that the satellite itself is located in this range, the limit of which will be the two extreme landmarks. In this case, our two extreme landmarks will be the edges of two houses adjacent to our tree.

Now, let's look at another option. Where the tree itself, in the direction of which the satellite we need hangs approximately, stands closer to one of the houses. Here, the range can be taken starting from the second from the edge of the window of one house, and the edge of the corner of another house (Fig. 5).

Rice. 5 Selecting the tuning range of the satellite dish to the satellite.

Satellite dish tilt angle

(pre-setting the initial tilt of the satellite dish)

We have decided on the horizontal search range. Now, let's look at the vertical initial position of the satellite dish, that is, its tilt.

I have already talked about how to determine the tilt of a satellite dish earlier.

According to the coordinates of my location, the tilt of the satellite dish will be 73.20° from the horizontal plane, or if measured by the declination angle, then 16.80° from the vertical plane (Fig. 1).

Rice. 1

Since it is not possible to immediately establish the exact tilt of the satellite dish mirror (there is no place to get a reference point from), we, in principle, do not need to know the exact data of this angle at all. I gave all the explanations and drawings so that you can roughly imagine what vertical position your satellite dish should be in. This will be useful if, for example, you tilted the antenna mirror too much (or raised it), then you immediately realized that the antenna should be moved back.

Now, we need to set the initial angle of inclination of the satellite dish mirror, from which we will begin the vertical adjustment. In my case, I will install the antenna mirror above the desired angle, about half (Fig. 2).

Rice. 2

Then, when setting up the satellite dish, I will lower its mirror in small steps until a signal appears. You may have a question, why exactly did I initially raise the antenna, and when tuning, lower its mirror down, and not vice versa? The point here is that the satellite dish itself, under its own weight, tends to lower its mirror down. And if we gradually raise it rather than lower it, then due to the play in the bolted connections, the antenna will move back a little, thereby making it difficult for us to adjust later.

Decide in what vertical position your satellite dish will be placed, and apply the above to your case.

If you don’t know what slope the mirror of your satellite dish will have, then you can put it in a vertical position, and also gradually lower the mirror (or if you live close enough to the equator, raise it) until a signal from the satellite appears. But this again will increase setup time.

Well, I think now it’s time to move directly to the search for a satellite, that is, to step-by-step setup horizontal and vertical position of our satellite dish...

Before you start setting up a satellite dish, that is, before searching for a signal from a satellite, check all cable connections. Don't forget to check that you have correctly connected the coaxial cable from the converter to the receiver. It should be connected to the connector with the inscription - IN(Photo 1), that is " entrance". In this case LNB IN- converter input (LNB - converter designation).

Photo 1. The cable must be connected to a connector with the initials - IN.

Attention! Since there is a difference voltage between the converter and the receiver (even when it is turned off), in order to avoid their failure, connect and disconnect the coaxial cable only when the receiver’s power is turned off (while touching the plug to the connector, a discharge spark may slip through).

Having connected all the cables, turn on the receiver, and then go to the menu where an indicator of the level and quality of the signal of the selected transponder is displayed. Since the satellite dish has not yet been configured, the indicator readings will be at zero (the indicators of some receivers may show a low signal level, that is, the level of the receiver or converter’s own noise).

The fasteners on the suspension device, that is, those fasteners that are responsible for the horizontal and vertical movement (Photos 2 and 3), should be slightly tightened. We will do this so that in the future, with little effort, we can move our satellite dish.

Satellite dish fasteners

Satellite dish mounting mounting bolts (option No. 1).

Satellite dish mounting mounting bolts (option No. 2).

Next, let's come to the design of the satellite antenna itself, and stand so that you can simultaneously move the antenna mirror and look at the TV screen. As I explained earlier, we need to observe the readings of the signal level and quality indicator, as in the example of receiver No. 1 (Photo 4 and Photo 5).

Preparing to set up a satellite dish

Before we begin setting up a satellite dish for a satellite, I think it would be useful to explain one more point regarding the input of existing transponders into the satellite receiver.

Satellite coverage map

Let's imagine such an example. The satellite receiver is correctly configured for the satellite antenna configuration (the correct parameters of the converter installed on the antenna are entered), and the parameters of the entered transponders of the selected satellite contain valid values. Further, when you try to tune a satellite dish to a signal from this satellite, no matter how you twist the mirror of this antenna, there was no signal. Why?

The point here is that any satellite also has such a parameter as the satellite signal coverage area, which I already mentioned earlier, that is, this signal can only cover a certain area of ​​the earth’s surface. And if we enter even valid transponders into the satellite receiver, then the signal from the selected satellite may simply not cover the area of ​​the earth’s surface where your particular settlement is located. Well, of course, there can be no talk of any signal reception from this satellite.

So, before tuning the satellite dish to the selected satellite, be sure to check not only whether the transponders are valid, but also check on the coverage map of the selected satellite whether your locality is included in this coverage area. That is, whether the selected satellite, with its beam, covers your geographic coordinates.

Express AM 22 53.0°E satellite coverage map from the website www.unionsat.ru

Using the table, we find the diameter of the satellite antenna, which corresponds to the given power. It is equal to 0.95 meters. I took 1.1 meters, that is, a little with a margin.

At the next, quite important stage, we have to configure the satellite dish to the signal from the selected satellite. Therefore, a little about life...

Alas, no matter how much I would like to talk about it, but as practice has shown, it is at this stage of setting up a satellite dish, after several unsuccessful attempts, that novice tuners lose all interest in the setup itself. Here, don’t get me wrong, I’m not talking specifically about you.
But still, if this happens, do not despair in any case, because even an experienced tuner can make the most simplest mistake. Be sure to check all cable connections and the settings you entered into the satellite receiver. And of course, be sure to try again.
It happened, more than once, that I heard something like this: “...what am I...”, “it turns out there, all that happened...” and so on.
Remember, to set up a satellite dish, you do not need to have any “normal” abilities, or any special gift from nature. YOU can do all this YOURSELF!

Searching for a satellite signal

Now, as I explained earlier, the direction of the satellite dish mirror, horizontally, should be in one of the extreme positions of the range of intended landmarks, for example, in the left. In Fig. 1, in this direction, a red vertical line is drawn.

Rice. 1 Start searching for a satellite signal.

If you have not determined the horizontal range in which the desired satellite is located (for example, you have not found landmarks), deflect the satellite dish mirror based on compass readings, plus a small margin. For my case, this is the situation I indicated in Fig. 2. I indicated the initial horizontal position of the antenna with a green arrow. This example, of course, is suitable for my location, since in your case, the direction to the satellite may be different.

Rice. 2 Initial horizontal direction of the mirror satellite dish.

Vertically, as I explained earlier, before searching for a satellite signal, the satellite dish must be tilted, approximately half the angle of inclination to your area (Fig. 3).

Rice. 3

If you also do not know the tilt of your antenna, then place it in a strictly vertical position (Fig. 4).

Rice. 4 Tilt the satellite dish before searching for a signal.

The general principle of this satellite dish setup is to scan a certain area of ​​the sky with the antenna mirror, although this sounds strange, but in fact, this is exactly the case. To be more precise, we need to scan that part of the sky in which we are absolutely sure that the desired satellite is located there.

We will begin the search for a satellite by rotating the satellite antenna mirror in a given search range in the horizontal plane, while starting the movement of this mirror from one landmark and ending with another. In Fig. 5, I indicated the edges of the search range with blue arrows.

Rice. 5

If you have not decided on the search range, then, guided by the compass readings, start horizontal search signal from the satellite, from the position that I showed on the previous page (in Fig. 3), to approximately the same position (as if in mirror image), on the other hand (Fig. 6). This method is usually used by more experienced installers.

Rice. 6

But, be that as it may, in both cases, you must be sure that the satellite is located exactly in the search area. If you are not sure about this, then be sure to expand it.

Since our satellite antenna looks with the plane of its mirror towards the extreme position of the selected range, we begin to slowly rotate it around the support pipe, from right to left (Fig. 7). You can, on the contrary, start from the other edge of the search zone, as you wish.

Rice. 7 Let's begin to slowly rotate the satellite dish mirror around the support pipe.

Here, I want to explain some important points related to this stage of setting up a satellite dish.

Each satellite receiver, when a signal appears at its input, has such a disadvantage as inertia, that is, it needs time to process the data stream from the satellite. Therefore, if you move the satellite dish mirror too quickly (!), the receiver will not have time to process it, and you will miss the desired point. Please take this into account when setting up your satellite dish at this stage.

Searching for a satellite signal (end)

Having reached the edge of the satellite signal search area, lower the satellite dish mirror by about one degree, and similarly move in the other direction. And again, we reached the edge, lowered the antenna mirror... etc. Do not forget, while doing these manipulations, to look at the signal level and quality indicator. Continue this way until the signal itself appears. I schematically depicted the trajectory of the satellite antenna mirror below in the figure (Fig. 8).

Rice. 8 The procedure for searching for a satellite signal.

If, with such actions, you do not end up in the very center of the satellite signal flow (Fig. 9), then your satellite receiver will still show some level of this signal.

Rice. 9 The procedure for searching for a satellite signal, the possible location of a satellite.

Usually it goes like this. While the satellite dish mirror is moving, at some point, the receiver sharply shows the signal level, and this signal disappears again. In this case, move the antenna even more quietly, but in the opposite direction, until a stable level of the satellite signal appears.

If, after scanning the entire area, you still do not receive a satellite signal, then return the antenna to starting position, and repeat the entire procedure again.

At this stage of setting up a satellite dish, very common mistakes are:

• The satellite dish mirror moves too quickly, and the receiver itself simply does not have time to process the signal from the satellite (that is, the data that this signal carries).
• They lower the satellite dish mirror in too large steps. In this case, the proverb fits well here - “The slower you go, the further you will go.”

If, when searching for a satellite signal, you made several attempts, and still did not get a signal... Then below, I will list possible mistakes and problems:

1. The transponder entered in the receiver settings is not valid.
2. The signal coming from the satellite you have chosen does not cover the coordinates of your settlement. That is, the coverage map of the selected satellite has not been verified.
3. The polarization of the satellite signal is incorrectly set in the receiver settings.
4. There is no line of sight between the satellite and the satellite dish. For example, a neighbor's house or a tree next to your house may be an obstacle.
5. The coaxial cable is not connected correctly to the receiver (to the wrong jack).
6. A converter is installed on the satellite dish, which is not suitable for the frequency range or type of polarization.
7. The diameter of the satellite dish is too small to receive a signal from this satellite.
8. There is a short circuit in the connecting “connector-connector” of the coaxial cable (a hair of the cable braid gets onto the middle core).
9. The search area is incorrectly selected (the wrong direction is selected).
10. The converter, on its holder, stands crookedly (turned sideways around the axis of the “L-shaped” holder). In principle, in this position, reception is possible, but if the signal power from this transponder is weak enough (to be received by the diameter of your antenna), then it will be difficult to catch it. The position of the converter around the axis of the holder is quite critical for receiving a signal in horizontal and vertical polarization . Converter with circular polarization, such a setting is basically not needed, and it will be enough to simply place it vertically.
11. The satellite converter or receiver may be faulty.

In my experience, as well as the experience of my friends, a malfunction of a satellite receiver or converter is a very rare occurrence. There were cases when, for example, the converter produced a weak signal, or stopped working normally after rain (defect in the seal of the housing). In principle, equipment malfunction is the last thing to think about. Be sure to check and double-check everything, and check and double-check everything again, and only then blame the equipment.

Further, I will assume that you received a signal from the selected satellite, and both level and quality appeared on the signal level and quality indicator. Below in the images, I have given photographs of indicators of satellite receivers with the presence of a signal, which I have already shown earlier.

Now, we need to more accurately adjust the satellite dish mirror to the maximum signal level. To do this, constantly watching the TV screen, that is, the signal level and quality indicator, tilt the mirror satellite dish right and left, up and down. At the same time, ensure that the indicator readings are as maximum as possible.

The procedure for tightening the bolts and nuts of the satellite antenna suspension

As soon as the signal level is at its maximum, we need to tighten the mounting screws. This must be done with caution, so as not to disrupt the previously carried out setting up a satellite dish. I have indicated the desired order of tightening the nuts and bolts in Photo 1 and Photo 2.

It is advisable to tighten the fasteners (nuts, bolts) that press the suspension itself to the support pipe simultaneously. Since it is practically impossible to do this at the same time, we do it this way. We tightened the first nut or bolt one half turn, then the second one, and so on.

In the first option (Photo 1), in more detail, the order of tightening the nuts is as follows - tighten one, or half a turn 1 - 2 - 3 - 4, then again 1 - 2 - 3 - 4... and so on until you press the suspension to support with sufficient rigidity. We tighten the bolts or screws with nuts for the vertical movement of the suspension (5) last (also one by one, half a turn).

In the second option (Photo 2), after tightening the fasteners of the suspension to the support, first screw in screw with nut 2 (which stops the vertical stroke of the suspension) until it stops, and only then 3.

While tightening the nuts, constantly monitor the signal indicator readings; if the level drops a little, slowly unscrew the nut that was being turned at that time, and begin to tighten the other one in the same way. In general, ensure that when the gimbal is securely fastened, the signal level remains at the same maximum level as before tightening the nuts.

And so, setting the satellite dish mirror to the right companion completed!

Next, in order to squeeze the maximum signal level out of the diameter of our satellite dish, it’s time to start adjusting the position of the satellite converter...

TECHNICAL CHARACTERISTICS OF SATELLITE ANTENNAS

SPECIFICATIONS	ANTENNA NAME
	STV-0.55-1.1 AUM	STV-0.6-1.1 AUM				STV-0.8-1.1 AUM	STV-0.9-1.1 AUM
Reflector dimensions	525x558	600x650				800x858	900x1000
Reflector material	steel	steel				steel	steel
Material thickness, mm	0,55	0,55				0,7	0,8
System type	offset	offset				offset	offset
Offset angle, degrees	19,65					19,67
Focal length, mm	367.5 (f/d=0.7)	300 (f/d=0.5)				565 (f/d=0.7)	450 (f/d=0.5)
Frequency range, GHz	10,7…12,75	10.7…12.75				10.7…12.75	10.7…12.75
Beam width, deg	3.3	2.8				2.1	2.0
Gain at 11.3 GHz, dB	34,5	35.9				38.1	39.1
Side lobe level, no more than..., dB	-(29-25log0)	-25				-(29-25log0)	-25
Cross-polarization level, no more than..., dB	-30	-25				-30	-30
Suspension type	azimuth-elevation	azimuth-angle				azimuth-angle	azimuth-angle
Elevation angle, degrees	0…45	0…45				10…70	10…70
Azimuthal angle, degrees	0…360	0…360				0…360	0…360
Antenna weight, kg	2,6	3,5				5,7	6
Tensile load per 1 bolt of a standard wall bracket (V=45m/sec), N						3050	4000
Working wind resistance, m/s		<25
Destructive wind force, m/s		>45
Permissible weight of the converter with irradiator, kg	0,260					0,26

Satellite antennas come in several types, depending on their area of ​​application: flat, parabolic, spherical, microstrip, horn. One of the most common and frequently used antennas are parabolic antennas, which include direct focus, offset and spherical antennas. Appearance and the principle of their operation is illustrated in Figure 1.

In accordance with the laws of geometric optics, flat electromagnetic wave, propagating perpendicular to the antenna aperture, after reflection from the paraboloid surface (mirror) will fall into the focus of the paraboloid (Fig. 2). A conical horn feed is installed at the focus, combined with a polarizer, to which, in turn, the converter is attached.

In terms of its electrical parameters, a paraboloid mirror is in many ways superior to alternative types antennas

One of the main electrical characteristics of any antenna is the gain G, proportional to the effective area of ​​the antenna. The effective area (or diameter of the antenna) depends on the power of the incoming electromagnetic wave, measured in decibels (dB) or watts (W).

Parabolic mirrors have a wide opening angle and a fundamentally achievable high surface utilization factor (0.4-0.7). This provides high gain with moderate antenna dimensions. The coefficient of surface utilization of paraboloid mirrors is determined by many factors - shading of the mirror by the irradiator, inaccuracy of the mirror profile, mismatch of the irradiator with the focus, uneven field distribution in the mirror aperture, and a number of others. The effect of these factors depends on the design, size and specific shape of the antenna.

Paraboloid mirrors differ, in particular, in the ratio of focal length to aperture diameter (f/D). Long-focus antennas include antennas with an f/D ratio greater than 0.5, and short-focus antennas with an f/D ratio less than 0.3. The focal length, in turn, is related to the depth of the mirror - the closer the focus, the deeper it is.

The depth of the mirror significantly affects the electrical parameters of the antenna. Shallow mirrors are irradiated more uniformly than deep mirrors, resulting in a higher gain. On the other hand, a wide antenna aperture increases the noise level.

Short throw antennas are widely used in radio relay lines, where the issue of detuning from interference is of paramount importance. They are also convenient for use in mobile reception systems.

For receiving television satellite broadcasts Long focal length mirrors are more suitable. However, they require more accurate calculation and adjustment of the feed, therefore, they are mainly produced for professional reception (Fig. 3), and in household systems antennas with an f/D ratio of the order of 0.3-0.5 dB are more often used.

The advantages of parabolic antennas include their broadband. Another undoubted advantage of parabolic antennas is the ability to receive signals of any polarization. Separation of polarizations, as a rule, is not associated with power losses. In satellite networks, this makes it possible to use the same frequency twice.

The disadvantages of this type of antenna are the large number of mechanical parts and exposure to atmospheric factors. Exposure to wind can distort the shape of the mirror and reduce surface utilization. This imposes serious requirements on the rigidity of the design of the mirror and the rotating support. The quality of reception can be affected by uneven heating of the antenna by sunlight, corrosion of the material and a number of other factors. This is especially noticeable for professional antennas with large diameters. A serious problem can be the accumulation of snow or water on the surface of the mirror.

The problem of sediment accumulation on the mirror can be solved by using offset mirrors, which are the upper segment of a paraboloid (Fig. 4). In northern latitudes, they are located almost perpendicular to the ground, and almost no precipitation accumulates in them either.

The main advantage of offset antennas is less shading of the mirror surface by the feed and, as a consequence, a higher surface utilization factor (0.6-0.8). The gain is especially noticeable for antennas with a small diameter (Fig. 5). The field in the aperture of an offset antenna has a more complex structure than in the aperture of a direct-focus antenna, which complicates the design of the feed. In most cases, the electrical parameters of offset antennas are somewhat worse than those of direct focus antennas. However, long-focus offset antennas, with careful calculation of the feed, can have very good electrical parameters and be used in professional systems.

The windage of the structure can be reduced through the use of mesh or perforated antennas.

Reception from different satellite positions generally requires reorientation of the parabolic antenna. According to the theory of mirror antennas, the sector of angles around the focus in which a signal can be received without a significant reduction in gain is +30. It is at this angle that satellite positions can differ, from which reception can be received by a fixed antenna without loss of signal strength. With a greater separation of positions, the mirror must be rotated, which leads to an increase in the cost of the suspension.

The problem of multi-satellite reception without mechanical rotation of the mirror can be solved using spherical or spheroparabolic mirrors. In such designs, the irradiator is located on an arc of radius r, the center of which coincides with the center of the circle R (Fig. 6).

The arc is called the focal line. If you choose r more than 0.56R, then the wave reflected from the mirror will be close to flat. Such antennas are used in automatic object tracking systems (Fig. 7). They use irradiators that move along the focal line, which makes it possible to scan over a wide sector of angles. A similar design can be used for multi-position satellite reception. Only instead of one movable converter, several fixed ones are installed on the focal plane, oriented to different satellite positions.

Spherical mirrors are inferior to parabolic mirrors in focusing accuracy and in a number of other ways electrical parameters. However, in some cases, they could be a convenient replacement for a whole fleet of fixed parabolic antennas.

Which antenna is better - offset or direct focus? Each antenna is good for its application.

Offset antennas are characterized by ease of installation along the wall of the house. They require less distance from the wall, in addition, snow does not linger on them, and the irradiator does not block the surface of the mirror. The size of the offset antenna is optimal up to 1.5-1.8 m.

Direct focus antennas have good characteristics from 1.5 m, because With this size of the antenna, the feed no longer “shades” the surface of the mirror. In a direct-focus antenna, the electromagnetic spot on the feed is free of distortion; the reflected electromagnetic wave from any point on the antenna arrives in the same phase to the feed. Parabolic direct focus antennas are antennas used for professional reception.

Below are approximate correspondences between signal levels and plate sizes:

50 dB - 60 cm

47 dB - 90 cm