Calculation of angles for self-tuning of the antenna. Choosing a location for the antenna. Finding values and working with acquired parameters

With the onset of the summer holidays, for many residents of large cities, life gradually moves out of town. One of the IT attributes of country life is the availability of satellite television. Some people try to install and configure their antennas on their own, similar to those of their neighbors, some resort to the services of installers, some calculate the installation parameters using a ruler on Google maps.

For those who are trying to install and configure satellite TV on their own, I would like to introduce the Geonames.ru service, which helps determine which direction to point the satellite dish.

The operating logic is as follows - the user selects a satellite operator or a specific satellite, then determines the antenna installation point on the map, and based on this data, the service calculates the direction and other installation parameters.

During the development process, it turned out that similar services already exist abroad, the most popular of which is Dishpointer.com, which is also used by installers. I tried to make my service aimed at Russian-speaking and less technically trained users, in fact, for housewives.

Next, I will tell you how the service calculates the necessary parameters and what difficulties I had to face during the development process.

In order to install the plate yourself, you need to determine several parameters:

Horizontal direction (azimuth)
Vertical direction (elevation angle)
Converter rotation angle

True and magnetic azimuths

True azimuth is used to plot the direction on the map in which the X axis runs parallel to the equator (parallel), and the Y axis is the meridian running from the south pole to the north.

True azimuth is calculated using the formula

K = PI/180;
a = latitude of place * k;
b = longitude of place * k;
c = satellite longitude * k;
Azimuth = (PI+arctan(tan(b-c)/sin(a)))/k;

Magnetic azimuth is oriented toward the Earth’s magnetic poles, which do not coincide with geographic ones, and is necessary to determine direction using a magnetic compass. In addition, magnetic poles change over time, and compass needles can also be affected by so-called magnetic anomalies.

In this regard, surveyors calculate tables of magnetic declinations (deviations of the magnetic azimuth from the true) for each “whole degree” geographic coordinate (180*360=6480 possible values) for each year. Thus, to obtain the magnetic azimuth, it is necessary to add or subtract the magnetic declination value for the given coordinates to the true azimuth.

As a source of the magnetic declination table, the Geonames.ru service uses the file magdec.bgl for 2012 - this is a declination table in binary form for the Microsoft Flight Simulator 2004 flight simulator.

In order to visually display the direction to a satellite on a map, you must keep in mind that the map is flat and the Earth is round. Therefore, the direction line will be an arc. The Geonames.ru service uses Yandex.Maps, in which you can set the geodesic=true parameter to display a line as a geodetic curve.

Elevation angle and plate tilt angle

Elevation angle is the angle of elevation of the satellite above the horizon. If the elevation angle is less than zero, then the satellite is not visible above the horizon and signal reception from it is impossible.

The elevation angle is calculated using the formula

K = PI/180;
a = latitude of place * k;
b = longitude of place * k;
c = satellite longitude * k;
Elevation angle = arctan((cos(b-c)*cos(a)-0.15126)/sqrt(1-cos(b-c)*cos(b-c)*cos(a)*cos(a)))/k;

It would seem that it is enough to tilt the antenna plane in accordance with the elevation angle and we will catch a TV signal from the satellite. But it's not that simple. This statement will be true if a direct-focus antenna is used, in which the signal reflection angle is perpendicular to the antenna plane. In the private sector, offset antennas are common, the signal reflection angle of which, depending on the design, is 110-116 degrees. We often come across antennas with a reflection angle of 116 degrees.

Schematically, the difference in antenna designs and directions of the reflected signal can be seen in

Calculation of rotation angles and position of a satellite antenna using the “Satellite Antenna Alignment” program.

I would like to immediately bring you up to date. Calculating angles and determining the direction to the satellite is not a sufficient condition for tuning the antenna to the satellite. The width of the antenna beam and its directional pattern is on average 1.5-2.5 degrees, depending on the size of the dish, so “catching” the desired satellite is not so easy, especially with a dish size of 0.9 m or more. For tuning, it is advisable to use SatFinder, an inexpensive satellite tuning indicator.

Before you start determining the angles and direction to the satellite, you can use a program to accurately determine the geographic coordinates of your locality; this may be needed for further calculations; this program can be found on the website: http://www.tour-info.ru/maps/locate_geo. html

Using the “Satellite Antenna Alignment” program, you can calculate the angles required when installing and tuning a satellite antenna to a satellite. With its help, the azimuth and elevation angle are determined for any geostationary satellite at a given geographic receiving point. Its main difference from similar programs is the ability to make calculations for all geostationary satellites at once, which gives an idea of their location on the “arc” and their availability for signal reception. The Satellite Antenna Alignment program also has a Russian interface.

To work, you need to download the latest version of the “Satellite Antenna Alignment” program from the link: http://www.al-soft.com/saa/saa.exe

The program remembers the list of geographical points for which the calculation was made. Subsequently, you will not need to enter the coordinates of these places again; you just need to select them from the table.
Working with the “Satellite Antenna Alignment” program begins with entering the geographic coordinates of the installation location of the satellite antenna; to do this, you need to enter the installation coordinates in the “Coordinates of the antenna installation location” section.

Designations: northern latitude - "N", southern latitude - "S" and, similarly, eastern longitude - "E", western longitude - "W". After you enter the coordinates, on the left side of the table you will receive the calculated angles for all satellites at once. The program calculates the azimuth and elevation angle of the antenna (elevation angle). The resulting azimuth is the direction to the satellite in degrees, defined as the angle from the north clockwise direction to the direction to the satellite. Elevation angle - the angle (in degrees) between the direction to the satellite and an imaginary tangent plane to the earth's surface at the receiving point. If the elevation angle is negative, it means the satellite is hidden behind the horizon and receiving a signal from it is, in principle, impossible. Thus, from the antenna installation site, all satellites available for reception are theoretically visible. Having determined the azimuth and elevation angle, you can quickly find your bearings and determine the direction to the satellite on the ground in order to assess the possibility of receiving a signal if there are obstacles in the direction of the satellite (houses, buildings, mountains, trees, etc.).

The above calculations were based on compass readings, but if you don’t have one at hand or you don’t trust its readings, you can use solar orientation.

The program allows you to calculate the azimuth to the sun. The calculation is performed for the same place for which you already specified geographic coordinates when calculating the azimuth to the satellites. The height above sea level is assumed to be 0 meters.

To calculate the movement of the sun with minute accuracy, you must specify the date (the current date is taken by default). The calculation results are formed on the left side of the table. For the sun, both the azimuth and the elevation angle at the current time are determined. This calculation gives you the opportunity to do without a compass when installing the antenna.

Procedure: first, the azimuth to the satellite you need is determined, and then the azimuth to the sun is calculated on the day the antenna is installed. Then, in the table, we find the azimuth of the sun that is closest to the azimuth to the satellite, and determine the time (and date) when the sun will be in the same direction as the satellite. At this moment in time, we turn the antenna directly towards the sun, the azimuth of the sun should coincide with the azimuth of the satellite. You can simply mark this position and rotate the antenna later.

When calculating, be sure to indicate your time zone (for Moscow this is +3 hours from Greenwich).

Additionally, the program calculates the azimuth of sunrise and sunset, as well as the time and elevation when the sun is due south.

When switching to the summer period, you need to add 1 hour to the obtained results of calculating the azimuth to the sun.

The program displays a simple diagram showing the sides of the horizon. The yellow sector indicates daylight hours, on the eastern part of the sector - sunrise, on the western part of the sector - sunset. On this diagram you can also display the direction to the satellite you need, to do this, select the satellite in the list on the left; the direction to it (azimuth) is drawn with a red line. If the elevation angle to the satellite is negative, then the red line is not drawn, because the satellite is not visible.

Currently, offset satellite dishes are widely used. Such an antenna, installed strictly vertically, already has a certain elevation angle (20...25 degrees). The program allows you to accurately calculate the satellite elevation angle and the actual antenna installation angle (in degrees from the ground plane). To do this, you need to enter the dimensions of your antenna in millimeters (height and width) in the program. The calculation is made only for antennas whose height is greater than their width, i.e. offset plates.

This program has a wonderful ability to calculate the angle between an obstacle in the path of a satellite dish and the conventional horizon on which the antenna is located. By specifying the height of the obstacle and the distance to it, you will determine this value. If this angle is greater than the elevation angle of the satellite you have selected, then reception under the given conditions of altitude and distance to the obstacle is impossible.

The program has another useful function: by selecting the satellite you need and activating the “Transponders” tab, the program downloads from the Internet all active transponders operating on this satellite.

Upon completion of the necessary calculations, the program has the ability to save them in a text file, on the Windows clipboard, or as a printout. The calculation table can be exported to MS Excel, MS Word, HTML and CSV files.

Calculation of rotation angles and position of a satellite antenna using the “Satellite Antenna Alignment” program.

To work, you need to download the latest version of the “Satellite Antenna Alignment” program from the link: http://www.al-soft.com/saa/saa.exe

The above calculations were based on compass readings, but if you don’t have one at hand or you don’t trust its readings, you can use solar orientation.

When calculating, be sure to indicate your time zone (for Moscow this is +3 hours from Greenwich).

Additionally, the program calculates the azimuth of sunrise and sunset, as well as the time and elevation when the sun is due south.

When switching to the summer period, you need to add 1 hour to the obtained results of calculating the azimuth to the sun.

First you need to choose a place to install the antenna. It must satisfy two conditions: direct visibility of the satellite and the ability to securely attach the antenna. The fact that a satellite in your city is above the horizon does not mean that it has direct visibility anywhere in the city. Almost nowhere on land we cannot see the entire sky; part of it is always obscured by mountains, trees or buildings, that is, obstacles that have a non-zero angular height. To check whether the satellite is obscured by such an obstacle, the following procedures must be performed.

First you need to determine the azimuth and elevation angle of the satellite. Azimuth (Az) - the angle in the horizontal plane between the direction to true North and the direction to the satellite. Elevation angle (Elevation, El) - the angle in the vertical plane between the horizontal and the direction to the satellite. The initial data is the longitude (orbital position) of the satellite and the geographic coordinates of your city. High accuracy is not needed - an accuracy of + 0.5 degrees is quite sufficient. Therefore, you can take coordinates from any geographical map, even small ones. If you live in a small town that is not on the map, the coordinates of another city located 100-200 km from you will do. There are several databases of geographic coordinates of cities on the Internet. For example, a convenient Russian-language “online” database is located here: http://goroskop. org/horoscope/location/index.shtml. To calculate the azimuth and elevation angle, you can use one of the calculator programs, for example Satellite Antenna Alignment, which can be downloaded for free on the Internet here: http://chishma.ru/download/satellite-antenna-alignment.html If you don’t have a computer, you will have to calculate the azimuth and elevation using the formulas:

Az = 180° + arctg (tg A / sin f);
El = (cos A cos f - 0.1509) / (sin^2 A + cos^2 A sin^2 cp)^1/2;
where Az is the azimuth, El is the elevation angle,
f - geographic latitude of the city (northern),
^r ^c - geographic longitude of the city and longitude of the satellite (eastern - positive, western - negative).

Then you should determine the angular height of the obstacle located exactly in azimuth to the satellite and compare it with the satellite's elevation angle. The easiest way to determine the estimated azimuth on the ground is to use a compass - you need to go to the antenna installation site and orient the compass body so that the “North” arrow aligns with the zero of the azimuth scale. An imaginary line passing through the arrow axis and the scale division corresponding to the calculated azimuth will indicate the direction to the satellite. However, this method is very inaccurate. Almost everywhere on Earth, the magnetic azimuth differs from the true one - the Earth’s magnetic poles do not coincide somewhat with the geographic one.

In addition, there are magnetic anomalies - distortion of the Earth's magnetic field by deposits of magnetic rocks. Even if we take these factors into account, the influence of large masses of iron that surround us in a modern city remains: building frames, pipelines, mechanisms, etc. The resulting magnetic compass error can be 10 degrees or more. Therefore, you can use a compass when there is no doubt: in a wide sector of angles around the desired direction, the angular height of obstacles is much less than the elevation angle of the desired satellite. If such doubts exist, you should use a more accurate method of determining azimuth - using a map.

You need to take a city map or a local plan; a printout from an electronic map will do just fine. Databases of electronic maps of cities can be found on the Internet, for example, here http://maps.yandex.ru, here http://www.mirkart.ru or here http://www.eatlas.ru. A large collection of Russian-language electronic maps is here: http://www.geocities.com/rip_ru. You need to put a point on the map in the place where the antenna is supposed to be installed, and using a protractor, draw the calculated azimuth from this point, remembering that on all maps the vertical direction corresponds to the direction to the North. Then, with this map, you need to go to the antenna installation site and turn the map so that the directions on the map coincide with the same directions on the ground. The easiest way to use directions is on the ground. The easiest way is to use the direction of the street - you need to orient the map so that the drawn street is parallel to the wall of a real house facing this street. Now the pencil azimuth on the map indicates the exact direction to the satellite. Determining azimuth from a map has another advantage - you can immediately see what obstacles are in the direction of the satellite, and they can also be used as landmarks for pointing the antenna. For example, the figure shows that the calculated azimuth intersects diagonally the roof of a high-rise building opposite and touches the corner of another high-rise building standing in the yard. Looking out the window, it is easy to find this direction.

If the antenna is installed on a wall, first of all you need to check whether reception from this wall is possible at all. Any wall limits the view to 180 degrees; you need to make sure that the calculated azimuth falls within this sector. Otherwise, you need to install the antenna on another wall of the building.

There is almost always some kind of obstacle in the calculated direction. If the height of the obstacle is certainly less than the satellite’s elevation angle, for example, if the satellite’s elevation angle is 25 degrees, and in the direction of the satellite there is only a distant low house, the angular height of which is approximately 5-10 degrees, we decide on the suitability of the antenna installation site. On the contrary, if in the direction of the satellite close to us there is a tall house, the angular height of which is obviously greater than the satellite’s elevation angle, we look for another place. If in doubt, more accurate means of measuring angular height should be used. Of course, the best solution would be a special device, for example, a theodolite, but it is not so easy to get. You can use one of the “folk” methods.

One method is described in Soviet school textbooks. You need to take an ordinary student ruler vertically in an outstretched hand and “measure” in centimeters or millimeters the distance b between the direction to the upper edge of the obstacle and to that point of the obstacle, the absolute height of which coincides with the height at which you are located. For example, if you plan to install an antenna on the wall of a house at the level of the third floor, and the obstacle is a neighboring five-story building, you need to measure the distance between its third floor and the ridge of the roof. Then, using a long ruler or tailor's meter, you need to measure the distance B from your eye to the ruler at arm's length. The angular height of the obstacle is approximately equal to:
B = arcsin(b/B)

The disadvantage of this method is the unreliability of the “artificial horizon”, because in fact, the third floor of a neighboring building may be much higher or lower than your third floor. If there are such doubts, it is better to use a pendulum protractor. A pendulum inclinometer can be purchased from companies that sell satellite equipment - it is generally a useful thing. But you can do it yourself; for this you need a small rectangular sheet of plywood, fiberboard or thick cardboard, a school protractor and a plumb line (thread with a weight). The protractor must be secured to a sheet of plywood so that the base of the protractor is parallel to the edge of the sheet (you can even redraw the protractor onto the plywood). In the place where the center of the protractor is located, you need to make a hole in the plywood and pass a plumb line through it. Having gone to the place of intended installation, you need to “aim” at the top point of the obstacle with the edge of the sheet parallel to the base of the protractor, and fix the position of the thread - mark it on the sheet with a pencil or simply press the thread to the sheet. The mark will indicate the height of the obstacle.

With the help of these simple tools, you can not only more or less accurately assess the visibility of the satellite, but also select a new installation location if the initially chosen one is unsuitable. Let's consider the same example: we place the antenna on the level of the third floor, exactly in the direction of the satellite there is a nearby five-story building. It turns out that its roof covers elevation angles of up to 15 degrees, and the elevation angle of the desired satellite is only 10 degrees, that is, the selected location does not provide direct visibility and you need to raise the antenna higher. How much? We determine a point on the wall of the interfering house, which has an angular height of 10 degrees. It is located five meters below the top point of the building, which means that our antenna only needs to be raised five meters for the satellite to become visible.

Independent calculation of satellite dish installation Satellite Antenna Alignment.

Satellite antenna, installation and calculation of direction angles to the satellite.

To make everything easier, we suggest you consider and use the good free Satellite Antenna Alignment program.

The rotation angle of a satellite dish is, simply put, two angles. The horizontal angle (azimuth (bearing)), and the vertical angle (elevation angle). Azimuth is the angle subtracted from the north direction in a clockwise direction. Due to the peculiarities of mounting the satellite antenna and the accuracy of calculations, preliminary targeting must be carried out first. We will talk about him first.

The easiest way to determine antenna rotation angles is to go outside and see where the antennas of other satellite TV users are pointing. Naturally, taking into account which satellite they are aimed at (based on advertising on dishes, or from a conversation with neighbors). The downside is the accuracy, and such that the first time you can even catch another satellite.

The first thing that will become clear is whether trees and buildings are interfering with reception. If they interfere, then you need to determine another mounting location, but it is highly desirable that the cable be no more than 10, maximum 20 meters long (the signal attenuation (almost 2 times) otherwise will reduce all your success in installing the antenna to a mediocre result).

A completely different question is how to direct the antenna exactly at these angles.

If you have a compass (however, metal on the roof and balcony cannot be avoided, as well as fictitious declination), you will still be able to approximately install the antenna, and then you can adjust it manually. In the Russian Federation, sometimes maps with the location of houses and objects relative to the north pole (N true) and even a view of the church (the cross on a normal church is oriented strictly to the North) help. According to the vertical angle, a little easier - along the plumb line and the protractor.

If there is nothing, then according to the Zenith of the sun (the highest point above the horizon). We did not specifically indicate the time (in our country this is a separate issue). Let's say around 2 pm today. This is the South, and it is from it that we count the direction to the satellite by eye, by sequential division horizontally (90/2 = 45, 45/2 = 22, 5, etc.) It’s simple, but it works.

Similarly, during installation you can estimate the angle of inclination of the antenna by sequential visual division vertically (90/2 = 45, 45/2 = 22, 5, 22, 5/2 = 11.25, etc.) Simple, but it works.

What accuracy is needed in calculations? Without going into an excursion into the dependence of the satellite's location range and accuracy, we will say that 2 degrees for the Russian Federation (for most satellites) is the maximum for the average value during calculations and installation. We also take into account the specific features of fastener accuracy, installation deviations and antenna deformation, which should be immediately reduced and taken into account.

Satellite Antenna Alignment is a program for calculating the angles required when installing a satellite antenna. The program is free and works from XP to Windows 7. It is in Russian, which makes the work easier.

The "Satellite Antenna Alignment" program is designed to calculate the angles required when installing a satellite antenna. The azimuth and elevation angle (elevation) for each satellite are calculated. The main difference from similar programs is the ability to perform calculations for all satellites at once. This gives a clear picture of which satellites are physically visible from the antenna location and which are not.

It should be remembered that in this program the calculation is purely theoretical, using formulas, and in real conditions, when installing the antenna, many more factors must be taken into account, such as various obstacles (buildings, trees), terrain, altitude, direction of transponders, polarization and so on.

Additionally, the program implements the calculation of azimuth to the sun, and now you can do without a compass!

This program will allow you to estimate the position quite accurately. The resulting calculation can be saved to a text file, copied to the Windows clipboard, or directly output to a printer. Export to MS Excel, MS Word, HTML and CSV files is available. It is possible to remember the list of places for which the calculation was made. The program has a multi-language interface (English, Russian, Ukrainian, German, Lithuanian, Dutch, Romanian, Polish, French).

The latest versions can be downloaded from the official website - http://www.al-soft.com/saa/satinfo-ru.shtml

Perhaps you will be asked to take a short survey, or the antivirus will reassure you, but usually not everything is so bad, it’s just that the program is free and the company somehow makes money. There are also older versions on the Internet without advertising and surveys (as well as without antivirus warnings).

You need to start working with the program by entering the geographic coordinates of your satellite dish installation point. Enter your coordinates in the "Coordinates of the antenna installation location" section. Northern latitude is "N", southern latitude is "S". Likewise, east longitude is "E", west longitude is "W". After the coordinates are entered, on the left side of the table you will receive a calculation of the angles for all satellites at once.

The azimuth and elevation angle of the antenna (elevation angle) are calculated. The resulting azimuth is the direction to the satellite in degrees from the north direction clockwise. Elevation angle is the angle (in degrees) between the direction of the satellite signal and the tangent plane to the earth's surface at your receiving point. If the elevation angle is negative, then the satellite is hidden behind the horizon and receiving a signal from it is, in principle, impossible. Thus, from your observation point, satellites are theoretically visible whose elevation angle is a positive value. Knowing the azimuth, you can quickly navigate and determine the direction to the satellite, identify obstacles in the direction of the antenna (neighboring houses, trees).

As mentioned above, the program operates with absolute values and calculates everything using formulas. Thus, the resulting azimuth is the angle relative to absolute north, and not from what your compass can show, because A compass is a very unstable thing, especially in urban environments. It's better to navigate by the sun)

Additionally, the program implements the calculation of azimuth to the sun, and now you can do without a compass! The calculation is performed for the point whose geographic coordinates you specified to calculate the azimuth to the satellites. The height above sea level is considered to be 0 meters. You can specify a date (the current date is taken by default) and calculate the movement of the sun in one-minute increments. The calculation results are displayed in the table on the left side. For the sun, both the azimuth and the elevation angle at the current time are calculated. Thus, this gives you the opportunity to do without a compass completely when installing the antenna. First, determine the azimuth to the satellite you need. Then calculate the azimuth to the sun for the day you plan to install the antenna. Find in the table the azimuth of the sun that is most equal to the azimuth to the satellite, and you will get the time (and date) when the sun will be in the same direction as the satellite. At the right moment in time, we turn the antenna directly towards the sun, the azimuth of the sun at this moment coincides with the azimuth of the satellite. Or just mark this position and rotate the antenna later. When calculating, do not forget to indicate your time zone (Moscow +3 hours from Greenwich). Additionally, the program calculates the azimuth of sunrise and sunset, as well as the time and elevation when the sun is due south.

The program does not take into account daylight saving time! Therefore, for summer time you need to add +2 hours to the obtained results of calculating the azimuth to the sun.

The program draws a simple diagram showing the sides of the horizon. The yellow sector indicates daylight hours, the eastern part is sunrise, the western part is sunset. On the same diagram you can schematically display the direction to the satellite you need. Select a satellite in the drop-down list; the direction to it (azimuth) is drawn with a red line. If the elevation angle to the satellite is negative, then the red line is not drawn (the satellite is not visible).

Currently, offset satellite dishes are widely used. Such an antenna, standing strictly vertically, already has a certain elevation angle (~20-25 degrees). You can enter the dimensions of your offset antenna (height and width) and the program will calculate the exact elevation angle for this antenna. The calculation is made only for antennas whose height is greater than their width. Enter the antenna dimensions in millimeters. Here you will also see the elevation angle to the satellite you have chosen, and the angle at which you actually need to install the antenna (in degrees from the plane of the earth)

There are ready-made calculations for the main cities of the Russian Federation

http://www.al-soft.com/saa/webreports/

For example, for St. Petersburg, the calculated angles for each satellite will help you when installing a satellite dish for satellite Internet or satellite television NTV-Plus, Tricolor TV, Rainbow TV, Platform HD, Continent TV.

Azimuth and elevation on satellites for Sankt-Petersburg – [Latitude: 59°55"N, Longitude: 30°15"E]
Satellite	Azimuth	Elevation angle

Calculation of angles for self-tuning of the antenna. Choosing a location for the antenna. Finding values ​​and working with acquired parameters

True and magnetic azimuths

Elevation angle and plate tilt angle

Calculation of angles for self-tuning of the antenna. Choosing a location for the antenna. Finding values and working with acquired parameters