Solar interference. Solar illumination

Solar interference- distortion of the radio signal received from the satellite as a result of interference with solar radiation. The sun is a star and emits energy not only in the visible (light) part of the spectrum, but also in the form of radio waves. When the receiving satellite antenna, the satellite it is pointed at, and the Sun are on the same line, receiving signals from the satellite is impossible: the transponder signals are blocked by the more powerful noise of the Sun. This phenomenon occurs twice a year: in early spring and autumn. Interference degrades the quality of communication and leads to failures.

The sun, like any star, emits energy not only in the visible (light) part of the spectrum, but also in the form of radio waves, including the centimeter range. When three objects—the receiving satellite dish, the satellite it is pointed at, and the Sun—are on the same straight line, receiving signals from the satellite becomes impossible. This occurs because the transponder signals are overwhelmed by the more powerful noise from the Sun. This phenomenon occurs twice a year - in early spring and autumn.

Solar interference occurs within 3.5 weeks of the autumn and spring equinoxes (March 21st and September 21st). During these periods, the Sun, making its annual journey, crosses the plane of the equator. Solar interference in February, March and April first affects earthly receiving stations located in northern latitudes, then affects stations located to the south. At the equator, the middle of the period in which solar interference occurs falls exactly on the equinox - March 21. Then the interference zone shifts to the southern hemisphere, and stations in southern latitudes are the last to experience the influence of interference. For them, the period of solar interference ends 3.5 weeks after the vernal equinox. In August, September and October, the picture is reversed, since the Sun at this time moves in the opposite direction - from the Northern Hemisphere to the Southern. The interference period for each specific station lasts just over a week. During this period, interference occurs every day, at the beginning of daylight hours - for the eastern satellites, at the end - for the western ones.

At first, interference manifests itself in the form of barely discernible noise in the image and sound, then day by day the noise becomes more significant, and in the middle of the interference period the reception breaks down completely. At the time of interference, especially in clear weather, it is necessary to move the antenna away from the satellite if possible. Rolled aluminum reflectors and plastic reflectors with a glossy surface are capable of concentrating sun rays at the focal point so “successfully” that due to high temperature The plastic parts of the irradiators melt and the electronics of the converters fail.

The days and times of the beginning and end of solar interference for each satellite for a particular receiving station can be calculated absolutely accurately.

The initial data for the calculation are:

• the geometry of the relative position of the Earth, the receiving station, the satellite and the Sun;
• antenna gain and width of the main lobe of the radiation pattern;
• used frequency range;
• noise temperature of the receiving system;

Vernal equinox:

Autumn equinox:

The last days of February - the first days of March - the time of spring solar interference for satellite receiving stations in the Urals and Western Siberia. At this time, the Sun, passing its daily path across the sky, appears for some time on the satellite line - receiving antenna, “falling” into the latter’s radiation pattern. The sun is a powerful source electromagnetic radiation over the entire frequency range, so during interference, reception of a signal from a satellite is usually impossible. This phenomenon is observed for 5-12 days, from 1 to 8 minutes every day at the same time. The duration of interference depends on the diameter of the receiving antenna and the frequency range.

Why is solar interference dangerous?

• For receiving systems of television companies and radio stations that carry out direct retransmission satellite signal on the air: during the passage of the Sun through the antenna's radiation pattern, reception failure is inevitable - a defect on the air. To prevent this, you need to prepare an alternative signal source and switch to it in advance.
• For receiving systems using large diameter antennas painted in light color: In clear weather, during interference, the sun's rays are focused by the antenna on the converter. This can lead to melting of the plastic parts of the irradiator and converter and failure of the electronics. To prevent this from happening, it is necessary to place a screen made of cardboard or opaque polyethylene in front of the irradiator in advance.
• For stations receiving signals from inclined orbit satellites using the RC2000B, RC2000C intelligent tracking controller from Research Concepts Inc.: if the tracking table data check procedure occurs during interference, the controller may point at the Sun and “ruin” the table row. This can lead to a repeated failure to take it a day later, even if the interference has ended by this time. To prevent this from happening, it is necessary to disconnect the controller from the network in advance for the duration of the interference, and turn it on again after reception is restored.

How to determine solar interference time

It is optimal to use the on-line calculator www.satellite-calculations.com/Satellite/suninterference.php. To calculate the interference time, you must enter the orbital position of the satellite (or select a satellite from the list), geographical coordinates receiving station (or select the nearest city from the list - there are several Russian cities there), select the frequency range (C -Ku), season (spring-autumn), enter the antenna diameter in meters, year and click the Calculate button. The program will display a schedule of start time, end time and duration of interference by day. It can be obtained as a separate html file to be printed or saved to disk; to do this, you just need to click the Print/Save As button.

The program works for any point on Earth, but it is focused on US receiving stations, so when entering data it is necessary to take into account some features

• The orbital positions of the satellites are calculated in degrees West longitude in a circular measure from 0 to 360 W (from the Greenwich meridian to the West). For satellites located above the Eastern Hemisphere, it is necessary to enter the value of eastern longitude with a minus sign, or recalculate the eastern longitude in a semicircular measure to the western longitude in a circular measure: W = 360 - E
• The longitude of the receiving point must also be entered in degrees west longitude in a circular measure. For the Eastern Hemisphere, it is necessary to put a “minus” before the value of eastern longitude, or convert it to western longitude using the same formula.
• When entering antenna diameter, use a period rather than a comma to separate decimal places. When entering a number with a comma, the program freezes.
• It should be remembered that Americans write the date: month-day-year, not day-month-year.

On September 27, a period of solar interference will begin in Russia. At this time, the Sun, the communications satellite and the receiving antenna of the ground-based satellite station are aligned on the same line, which leads to a deterioration in the quality of reception of television and radio channels from the satellite, up to complete loss. Interference is observed twice a year, for three and a half weeks from the days of the autumn and spring equinox (September 21 and March 21).

RTRS uses all available technical capabilities to minimize the influence of solar interference on the reception of television and radio channels by television viewers. For communication satellites located in different orbital positions, the time of adverse effects of solar interference is different. Therefore, RTRS branches organize local reception of television and radio channels from backup sources signals. As backup sources they can be used as digital packages programs (federal version of the first multiplex and the second multiplex), and direct broadcast satellites (program packages “Tricolor TV”, “Tricolor TV Siberia”, “NTV-Plus”, “NTV-Plus Vostok”, “Continent TV”, etc. ).

Thanks to the reliable operation of modern RTRS equipment, the majority of Russian television viewers do not notice interference from year to year.

In the Tyumen region, including Khanty-Mansiysk and Yamalo-Nenets autonomous okrugs, interference will be observed from September 27 to October 21.

The influence of autumn solar interference on the reception of television and radio channels in the region

Owners satellite dishes sooner or later they come across such a concept as “solar interference”. This usually happens in the first year of operation of the antenna, when the provider himself warns users about the possibility of signal loss for precisely this reason. Let's figure out what it is and why radio signal transmission deteriorates or disappears altogether.

What is solar interference

Any star, including our Sun, emits not only visible light energy, but also radio waves in the centimeter range. When the sun is in a direct line with the satellite and satellite TV antennas, signal reception is not possible. This is all due to the fact that the Sun creates interference, and the transponder signals are simply blocked by noise from the Sun.

When does this happen

This phenomenon occurs 2 times a year - in autumn and spring. It is during these seasons that solar interference can be observed. Most often, this phenomenon occurs within 3.5 weeks from the days of the spring and autumn equinox. At this time, the Sun makes its annual journey, crossing the plane of the equator.

In February and March, interference first affects earth stations located in northern latitudes, then affects more southern receiving stations. At the equator, the most significant event falls on September 21 (equinox). The zone then moves to the southern hemisphere. It is the southern receiving stations that are the last to experience the influence of solar interference, which ends 3.5 weeks after the spring equinox.

In August, September, and October the picture is reversed, because the Sun begins to move in the opposite direction - to the Southern Hemisphere from the Northern. During this period, the interference period for each station lasts for one week. Every day during this time interference occurs. Moreover, in the morning, eastern communication satellites are influenced, and in the evening - western ones.

How does it manifest itself?

At first, with a weak influence, weak noises may appear on the TV screen, which become strong during the day. At the very peak of solar interference, there is absolutely no signal from the satellite. Therefore, you should not worry about this and think that something is broken or the antenna has moved to the side. Everything is fine with you, and this phenomenon is completely normal.

What to do

At the very peak of the signal, in the middle of a sunny day, it is advisable to move the antenna away from the satellite line altogether. This is done to prevent the plastic parts of the irradiators from melting. This may result in complete breakdown of the converter electronics. Because of this, aluminum reflectors are very “successful” in concentrating the sun’s rays at a focal point.

So if found strong interference or complete loss of signal from the satellite, check with your provider to determine whether solar interference has occurred or the signal is being lost for another reason. If this is an interference effect, then go up to the roof (or wherever you have an antenna installed) and move it to the side. And then let it have to be aimed at the satellite again. It's better than spending money on new electronics converters. Although there are more simple ways. For example, you can simply cover the antenna with something opaque that does not let the sun's rays through.

Harm from solar interference

First of all, radio stations and television companies that relay the signal from the satellite onto the air suffer from solar interference. As a result of this phenomenon, they lose the signal, which is fraught with defects on air and loss of ratings. Therefore, all self-respecting companies prepare alternative signal sources and switch to them before solar interference takes full effect.

Stations that receive radio signals from the Express and Horizon satellites are also affected. A special feature of these satellites is their movement in an inclined orbit. Pansat XR4600D, Drake ESR-700 and ESR2000XT-plus receivers are used to receive the signal. As a result of interference, these receivers can “lose” satellites and begin tracking the sun. Therefore, it is necessary to program the receivers in advance for the specified satellites as stationary and turn off tracking when such a phenomenon occurs. Once the interference wears off, the receivers must be reprogrammed to these satellites as inclined orbit satellites. All these actions need to be performed 2 times a year, and this extra costs effort. However, if not used, you can simply switch it to Stanby mode for the duration of solar interference.

Last but not least, stations receiving signals from the Express and Horizon satellites with inclined orbits suffer. Occasionally, tracking table data may be checked during interference. If at this time the controller is pointed at the Sun, it will spoil the entire table row. As a result, repeated disruption of signal reception cannot be avoided even if the interference ends on the second day. Therefore, the controller is disconnected from the network in advance and, after normal reception conditions are restored, it is turned on again. The main thing is not to miss this moment.

Regular users who use large diameter antennas may also suffer. In clear weather, the sun's rays are focused on the converter using this very antenna. The converter becomes hot and may melt. This will cause it to fail, and the user will have to replace it with a new one. Therefore, watch out for solar interference and when it occurs, either move the antenna to the side or cover it with cardboard or opaque film. Otherwise, the sun's radiation from the antenna will melt the receivers.

Determination of interference time

Eat special programs for solar interference to occur. One of them is called Look, and it is distributed free of charge on the Internet. The program is simple and even primitive, it simply shows exact date when the interference is maximum. You can also use it to find out the first and last days"session" of interference. For this from specified date you need to count the number of days back and forth. The number of these days is also determined by the program depending on the specified diameter and range of the antenna. But it is worth noting that this program only works with receiving stations in the Northern Hemisphere.

Interference Determination Calculator

If you haven’t found or don’t want to download the above program, you can use an online calculator. It is presented on the PanAmSat website. However, to work with it you need to have some data.

For example, you need to know the orbital position of the satellite (you can select from the search or enter manually), the coordinates of the receiving station (you can select your city listed in the list), frequency range, antenna diameter, season. If you have all this data, you need to enter it into the online calculator and click “Calculate”. The program will show the start and end times of the interference. All data will be provided in HTML format, so you can print it out and hang it on your wall to always remember it.

Features of working with the calculator

Note that although this program is focused more on the USA, it works for all receiving stations. However, there are some features of working with this program:

1. When entering antenna diameter, you must enter values ​​with decimal places, using a period rather than a comma. Otherwise, the program will freeze and will not be able to calculate anything.
2. Satellite positions are indicated in degrees west longitude from 0 to 360 W (west of). Therefore, for satellites in the Eastern Hemisphere, you must enter values ​​with a minus sign.
3. Also, don't get confused about dates. In the USA they write the date like this: “month-day-year”. We are used to indicating the date like this: “day-month-year”.

Usually this calculator is quite enough to accurately calculate the onset of interference and its end. But if you can’t figure it out, then visit thematic forums on satellite television. There are usually topics for determining interference for different cities. Moreover, some providers warn users about the onset of this period and even give advice on how to “survive” it correctly.