satellite broadcasts are transmitted by the method of transmitting waves at very short centimeter frequencies. For this purpose, two levels are used: Ku-band (from 10.7 to 12.75 GHz), C-band (3.5-4.2 GHz). At such magnitudes, an electromagnetic wave that has the ability to overcome more than 35 thousand kilometers from the satellite to home antenna, in the cable is instantly extinguished. It is for an intermediate, lower indicator that satellite converters serve. According to international standards the spectrum of this frequency is in the range of 900-2150 MHz. These frequencies are then sent to special cable to the microwave input of the receiver.

General principle of operation

To reduce the received frequency spectrum, a pair of local oscillators with high-frequency source stabilizers are built into the converter. The input indicator is reduced by subtracting the local oscillator frequency from it.

Another nuance is that the signal arrives with a low vanishing power. This is unacceptable in receiver paths. In this regard, the second important function satellite converters - amplification of received pulses. It should be noted that the device accumulates not only the useful signal, but also incoming parallel noise. Also, the device adds its own background, like any other similar device. In the English interpretation, converters are designated as Low Noise Block (LNB), which emphasizes the peculiarity of any device. of this type in terms of low level noise.

Device and equipment

In the receiving part, between the antenna and the satellite TV converter, there are two more elements - a polarizer and a feed. All parts are mounted in a single structure, located at the focus of the antenna device. The purpose of the feed is to make more careful use of the mirror surface and to maintain the maximum gain of the antenna gain. The polarizer serves as a setting for selecting the desired type of polarization.

The complete set of the considered devices can be the following:

• Release of converters separately.
• Models with built-in polarizer.
• A design that combines an offset irradiator and a polarizer.

In the first variant satellite converter ends with a rectangular type flange, the second model with a round element, and the third version with a irradiator.

When choosing an irradiator, it is necessary to take into account its shape, which should fit at the joints to the antenna used. In addition, attention should be paid to the offset or direct-focus type of the receiving element, as well as the ratio of the focal length to the diameter of the antenna. For offset models, an indicator from 0.6 to 0.8 is suitable, while for direct-focus models it should be 0.3-0.5. The best option will be the purchase of an antenna complete with an irradiator, which will guarantee their compatibility one hundred percent.

Criterias of choice

Your choice of converter satellite dish influenced by several factors. The main one is the frequency range that is planned to be used. European satellites predominantly broadcast in the Ku band. Some Russian companies operate on the same frequencies.

The second type of device is a C-band converter. These frequencies are geared towards professional reception. Some models are available with combined type converters. There are plenty of models aggregating with Ku-bands on the market. It should be noted that the width of this indicator is 2.055 GHz. It does not make it possible to synchronously transfer the signal to an intermediate frequency. In this regard, it is divided into three streams (GHz):

1. FSS - 10.7 - 11.8.
2. DBS - 11.8 - 12.5.
3. Telecom - 12.5 - 12.75.

Satellite converters of the second and third bands are focused on receiving certain packets.

Universal modifications

Most of the manufactured converters aggregate with the Ku type range. They are equipped with two local oscillators that convert the upper and lower ranges. The elements are switched by means of a signal that is broadcast from the receiver via a cable that serves to receive an intermediate frequency from the converter.

Modern devices, in comparison with their predecessors, have a universal design, switching ranges in them is carried out by means of a tone signal. The universal circular satellite converter differs in the number of signals used for switching ranges and polarization.

The local oscillators in such devices range from 9.75 to 10.6 GHz. This design greatly simplifies the setup of the receiver, up to automatic configuration after selecting the corresponding menu item.

Satellite converters for Tricolor

For those wishing to take both ranges at once, several options can be advised. It is realistic to install a pair of converters on the antenna with its own polarizer and feed. In this case, one of the feeds will be slightly out of focus, which will reduce the directional gain. This path is considered quite troublesome.

The second option is to purchase a C/Ku rotor device containing both range feeds, bifurcating the incoming signal stream. Such elements are equipped with electromechanical type polarizers. This design simplifies the installation process, but has several disadvantages. First, there are tangible losses in the power of the Ku band pulses. Secondly, there are frequent breakdowns moving parts of the rotor, especially at sub-zero temperatures.

Finally, the third option is considered the simplest. You just need to install a combined converter, which has not yet received much distribution.

Polarizer

This device allows more efficient use frequency range transmitted waves, which doubles the number of broadcast programs. Tuning frequency desired channel, synchronously set the required polarization. For example, a linear satellite converter generates vertical and horizontal waves during polarization. The circular analogue generates right and left pulses of the circular type.

The polarizer filters the waves and passes only pulses of one selected polarity to the converter. It is worth noting that Russian satellites have a predominantly circular action, while European counterparts - linear system. For confident reception of circular waves, another element is mounted - a depolarizer that transforms circular polarity into a linear direction.

The discreteness of the change in polarization is another parameter that distinguishes polarizers. IN universal models the plane discretely changes by 90 degrees. There are also electromagnetic devices that smoothly change the plane of polarization and options with mechanical movement of the probe. Due to the presence of moving parts, electromechanical modifications are less reliable and require three control pulses from the receiver, unlike magnetic analogues, which require two signals.

Phase modulation

With the advent digital packages type "Tricolor" and "NTV Plus", the European reception scheme based on the use of a polar antenna and universal converter. It is connected with high quality signal and digital method broadcast of most programs. Phase modulation is very sensitive to transformations, which can lead to failures when using a magnetic polarizer. In addition, it requires the use of certain materials for the depolarizer plate. As components, dielectric grades are used, designed to work with microwave-type pulses.

If you decide to mount a magnetic polarizer, you will need to additionally purchase a converter with a rectangular flange and an irradiator. When distributing the signal to several apartments, it is optimal to use a satellite circular converter (2 outputs or 4 outputs). Usually they are equipped with a built-in polarizer (voltage - 13-18 V). According to the type of output pulses, such devices are divided into versions with one or two pairs of identical outputs with independent switching of polarization and ranges. Similar devices suitable for connecting 2-4 apartments. The second type - with outputs output by vertical and horizontal polarization plus double division of the ranges in the presence of 4 outputs. These devices are designed for large quantity subscribers.

Two-pin converters

This type of device is convenient to operate for those who plan to limit themselves to receiving the upper or lower range. With such a scheme, a horizontal type pulse enters one input of the receiver, and a vertical signal enters the second. Analogues of this modification with four outputs are used in cable networks or to organize a small collective reception. In the second case, reception from the outputs of the converter is carried out through switches for subsequent wiring to subscribers.

Community circuits have higher standards for signal gain. This value is measured in decibels, its permissible indicator varies between 50-70 dB.

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To begin with, we will select this converter for the signal that comes from the selected satellite. Or rather, from his chosen transponders.

For clarity, let's take another look at the table of transponders of the Express AM 22 53.0 ° E satellite, and select the converter necessary to receive the signal.

To determine the type of converter, we need two parameters from this table. This is the frequency, and the type of polarization. I marked the required columns in green.

As can be seen from our table, the transponder frequencies are in the range of 10974 ... 11481 MHz (megahertz). We look at the table of "C and Ku" ranges below, and determine which of these ranges the frequency of the selected channels belongs to.

The selected frequency spectrum 10974 ... 11481 MHz refers to the Ku band standard, from this we determine that the converter we choose must support this particular frequency range.

Quite often, at least, at the time of writing this topic (because in the range C - the signal is coming mostly from older satellites, and it is used less and less), in the transponder tables of one satellite, both of these frequency ranges may be present. That is, both range - C, and range - Ku.

In this case, you will have to choose which transponders suit you best. So, accordingly, the converter will be either "Ku" of the range, or "C". If you want to receive a signal from all transponders, then in this case, you need to purchase a two-band converter. And that means satellite antenna should be from 1.5... meters in diameter (because, for C-band, a larger diameter antenna is needed). As a rule, two-band satellite converters are much more expensive.

Now, with regard to polarization. According to the table, we see that on the Express AM 22 53.0°E satellite, there are two types of polarization. This is a linear vertical (V - Vertical), and a linear horizontal (H - Horisontal).

Both of these polarizations are combined in one type of converter - universal linear converter. With it, we will be able to receive a signal from almost all transponders from this table.

If you come across transponders with circular polarization (Circular), then you need to use a circular converter. Or call it a circular universal converter (since it also uses two types of polarization), which supports circular right (R - Right) and circular left (L - Leftl) polarizations.

In the event that you want to receive a signal with both linear and circular polarization, you also need a converter that supports both of these polarizations. As a rule, such a converter has two pairs of independent outputs, from which signals received in linear and circular polarizations are taken separately. To connect such a converter, with two outputs, to one input of a satellite receiver, you will need to use a special DiSEqC switch, which will connect your receiver to one output of the converter, then to another ().

DiSEqC switch - Serves for remote, switching between different receiving devices. For example, between two, three ... (etc.) satellite dishes, converters, as well as a converter with two or more outputs.

At first, when I still had little experience, I purchased a converter not with linear polarization, but with circular, that is, a circular universal converter (Circular Single LNB). With such a converter, there could be no question of receiving a signal with linear polarization. When I installed satellite dish, there were almost no such transponders at all (meaning open Russian-speaking, with circular polarization), well, perhaps perhaps "NTV +", but now, on this moment(i.e. at the time of writing this page), the rather popular Russian project "Tricolor TV" was already in full swing, broadcasting several software packages from one transponder (one free, and paid START and NIGHT), in this case it would be suitable it is this converter, Ku band, with circular polarization. In any case, at that moment, I needed a universal linear one. In addition, my receiver did not support those encodings in which channels with circular polarization went.

Subsequently, I had to buy a universal converter, with linear polarization, capable of receiving at that time the transponders I needed.

As I mentioned, setting satellite dish, I not only wanted to see for myself satellite TV channels through the receiver, but also, having installed a DVB-card in the computer, have access to satellite internet thus making the most of the opportunities that now present themselves.

Therefore, when using satellite dish, I had a need to exit the converter, not one signal, but two. To do this, I had to purchase a special converter with two independent outputs, designed to receive signals with linear (V, H) polarization. It consists of two identical converters in one housing, which have one irradiator (Photo 7).

Photo 7 Satellite converter with two independent outputs.

In principle, one could go to other more simple way, leaving on antenna converter with one output. For such cases, there is a special splitter, the so-called Splitter (Photo 8). But this method has its pros and cons. And here are some.

Photo 8 Splitter - signal splitter.

The advantage of such a splitter will be: first, relatively low price such an upgrade (at the time of writing this page), about 80 - 150 rubles, second, you do not need to change the converter, risking knocking down the setting satellite dish, and the third simple manipulations in installation.

Now, as for the disadvantages. To deal with this, you need to know a little about the principle of operation of the converter itself, or rather, the schematics of its power supply directly in this case.

Converter power

Imagine some kind of electronic device, for example, a pocket receiver. Without which it will not work, even if all electronic circuit serviceable? The answer here suggests itself. Of course, if we do not put batteries in it. That is, we will not provide him with a normal power supply. The converter is also no exception, like any electronic device it also needs power. Now imagine that in the receiver, you want to switch from one radio station to another, what will you do in this case ... of course, turn the tuning knob or switch to another range using the toggle switch. And what about the converter? After all, you can’t climb onto a satellite dish, no matter what you turn or switch.

So the developers came up with the idea to control the converter remotely, using the same cable that carries the satellite signal. So, in order to control the switching of the type of polarization, the converter is supplied with different voltages, as if, using the example of a pocket receiver (imagine if it has neither a tuning knob nor a range switch), when switching from one radio station to another, we will change the number of batteries in the battery compartment. Let's say one radio station will be broadcast if there are four batteries in the receiver, and another if there are six of them.

In a converter with linear polarization, if vertical (V) polarization is used, then it is supplied with power equal to 13 ... 14 volts, and if horizontal (H), then 18 ... 19 volts. Here I think the principle is clear to you.

Now, about the main disadvantage of using one converter to two receiving devices through a splitter, so to speak, what is its essence.

The point is that the satellite converter can only be powered by one voltage at a time. That is, either 14 volts or 18 volts. And this means that the polarization can only be either vertical (V) or horizontal (H). And here's what we get. If on a satellite receiver you will watch a TV channel broadcast in vertical polarization, then on a computer with a DVB-card (well, or on a second receiver), you can simultaneously use vertical polarization, although the TV channel may be different.

Such a disadvantage becomes very significant if one satellite antenna, with a converter (which has one output), through a splitter, is used for two apartments. One neighbor wants to watch football, the other, whatever the movie, and the polarizations of these channels are different (and it’s not far from a quarrel).

The advantage of a converter with two independent outputs is that it does not matter which output will have which polarization (in this case, linear "V" and "H" are meant). The disadvantages include a rather greater weight than a converter with a single output, and of course a high price. At that time, it cost me 980 rubles (whereas I spent 270 rubles on a converter with one output).

So, if you have two satellite receivers, then in this case it is better to use just such a dual converter.

Well, it remains to attach our converter to its holder, and of course to the "L-shaped bracket" of the suspension structure itself satellite dish. Below you can see, given by me, the mounting assembly option satellite converter by clicking the left mouse button on the image (Photo 9).

Photo 9 Converter on holder satellite dish.

Parameters of satellite converters

(marking of satellite converters)

The photographs below (Photo 1 and Photo 2) show two satellite converters, with circular and linear polarization, Ku-band. As you probably noticed, appearance they are no different, except for the inscriptions on their markings. These converters are designed to be installed specifically on offset satellite dish. In view of the fact that offset and direct-focus antennas have a significant difference in the method of attaching the feeds of the converters, the converters themselves are divided into those used for offset and those used for direct-focus satellite dishes .

Converters for installations for offset satellite dish

Now, let's determine by what criteria the type of satellite converter is determined. On "Photo 3", the place of marking for this model is shown.

Photo 3 Place of marking of the satellite converter (for this model).

For greater clarity, let's zoom in on the converter markings (Photos 4 and 5).

Judging by the logo, the converter was made by a fairly popular at that time manufacturer satellite equipment, "Golden Interstar".

Here are four main criteria that I try to pay attention to when choosing a satellite converter:

The first two determine the parameters of the signal that will be received from the selected satellite. The third and fourth determine the quality indicators of the satellite converter.

1. Type of polarization - Circular (right and left), and Linear (vertical and horizontal).
2. Frequency range - C or Ku.
3. Noise figure - the larger this factor, the less the quality of the received signal will be.
4. Gain coefficient - the larger this coefficient, the stronger the received signal will be amplified (it should be borne in mind that both the signal itself and the noise are amplified).

Below in the image of the labeling of the converters (Photo 6 and Photo 7), I have highlighted some of the values ​​with different colors.

1. CIRCULAR - circular polarization. UNIVERSAL - linear universal polarization.

2.N.F. - 0.2 dB - noise figure (measured in decibels). The lower the noise figure, the better the signal will be. There are converters with a large noise figure, for example 0.3 dB (or completely outdated 0.6 dB), they are usually cheaper, but ... I would not save on this parameter (tested by practice).

Note: The noise of satellite C-band LNBs is not measured in decibels, as in Ku-band LNBs, but in degrees Kelvin (for example, a noise figure of 10K).

3. 11.7-12.50 GHz - the frequency range to which this satellite converter belongs. In this case, there will be Ku-band (Ku-band).

Note: The manufacturer decided not to indicate such a parameter as "gain" on the converter marking.

As you can see, not all parameters are indicated on the marking of the converter applied on its body. Therefore, when purchasing it, look not only at the tag, but also at the marking indicated on the packaging box (Photos 8 and 9), well, or on the passport. For more detailed information, on the example of a satellite converter with two independent outputs, from the company "Golden Interstar", left-click on the image.

(marking of satellite converters)

1. Marking of the satellite converter "Golden Interstar" linear polarization with two exits.

2. Marking of the satellite converter "Golden Interstar" of circular polarization.

The remaining parameters, we will need when setting up satellite receiver(receiver), there I will continue the discussion of converters in more detail.

Now, set to satellite dish the converter you have chosen, and it is time to stop, on the choice of a satellite receiver (receiver), that is, which model you want to use specifically for your requirements.

Some

types of satellite converters.

Converters ("LNB" or "LNA"), as well as a radio signal, are divided into reception of a specific frequency spectrum, that is, again, a range.

satellite converter

- short name LNB (Low Noise Blockconvertor). "Low" - low, "Noise" - noise, "Blockc-onvertor" - converter block. The domestic name of the LNA converter is Low Noise Device.

You may come across such designation of converters, LNB or LNBF - in principle, correct name both. But given that the converters going to offset satellite dishes, have an inseparable body with a feed (Photo 1), then it would be more correct to use the name - LNBF (LNB - converter, + F eeder - feeder, i.e. receiving antenna, or feed = LNBF).

There are types of converters where the irradiator is attached to the converter body, and they are assembled, as a rule, before mounting on satellite dish. In this case, the name LNB + F would be more correct (LNB - converter, + Feeder - irradiator).

Satellite converter bands

Satellite converters, which are usually used to watch home satellite broadcasting, by the way and not only, are also designed to receive: C-band, Ku, well, or combined C and Ku-band.

Ku-band satellite converters are more common because the diameter satellite dish, when using such a converter, is usually from 0.5 to 1.2 meters. When receiving the C-band, the size of the antenna is slightly larger.

For example, to receive a Ku band signal from the Yamal 201 90.0 ° E satellite, you can use satellite dish with a diameter of 0.9 - 1.2 meters, and for receiving the C - band, from the same satellite, it is advisable to use an antenna of at least 1.5, and preferably 1.8 or 2.0 meters.

Note: dimensions satellite antennas are given only approximately, how to calculate its more accurate parameter, we will consider a little later.

There are many models of satellite converters, different both in type and appearance. Below are photos of some of them.

Polarization of converters

In addition to the frequency spectrum (range), converters, again, like the radio signal, differ in the type of signal polarization. Moreover, two types of polarization can be present at once in one converter.

Here are the two main types of converters you may encounter:

1.

Linear universal satellite converter

(Universal) - in this type of converter there are two types of polarization:

Linear horizontal(H - Horizontal).

Linear vertical(V - Vertical).

2.

Circular Satellite Converter

(Circular) - in this type of converter there are also two types of polarization:

Circular right (R - Right).

Circular left (L - Leftl).

In the name of a circular satellite converter, the word "universal" may also occur, since it contains two types of polarization "right" and "left", but ... do not confuse it with a linear converter.

Converters can also be single- and dual-range. Dual-band converters capture a slightly larger portion of the frequency spectrum. Manages range switching satellite receiver(it sends a special tone signal to the converter).

A selection of the type of satellite converter, so to speak, is an individual approach, and each user chooses it in accordance with his requirements. That is, for the type of signal that he is going to receive from the satellite. Also, you should pay attention to the number of receiving devices (for example, a converter with two outputs to two receivers located in different rooms, or a receiver and a computer DVB-card, etc...).

About some application of satellite converters, as well as some points of the principle of its operation, I will stop in the section - installation and configuration of a satellite dish, that is, during the installation itself and satellite dish settings.

To start choosing the satellite you need, or rather, to the fact that it broadcasts, it is not enough to know the configuration satellite antennas. You need to learn more, understand the table satellite transponders. After all, it is this table that displays what this or that satellite transmits, and with what configuration of satellite equipment (to put it simply, what set), we can receive a signal from this satellite.

Radio amateurs are well aware of what a satellite converter is. But in most cases, this term represents the most common KU range converter, and few people know that satellite television uses the C range (3.7-4.2 GHz).

The C-range converter has a similar structure, but visually it is slightly larger than the KU converter and is used to a greater extent on direct-focus mirrors.

There is also a variety for offset - a flange converter.

C range has a number of advantages over KU.

Its reception is more stable in bad weather. At a time when there is nothing at all in the KU or squares - C is steadily going. Antennas for receiving C can be made of mesh materials, thereby reducing the windage of the structure.

Maybe biggest disadvantage, this is what antennas are needed to receive from the C band large sizes. But on some forums they talk about good results on small plates. And all thanks to a home-made alteration From the converter for offset antennas.

As you know, the local oscillator frequency of the universal KU converter is 9750 MHz / 10600 MHz, and in most tuners it is set by default. In converters from the C band, when setting up, it will be necessary to set the receiver to 5150 MHz / 5700 MHz and even then set up the desired satellite.

To receive satellites broadcasting in the C band, one converter will not be enough. After all, the broadcast is carried out mainly in circular polarization (right and left), and the converter takes linear. To receive a circular one in the converter, it is enough to place a plate of glass, textolite, plexiglass, plastic (selected according to experience), at 45 * between the receiving probes, not reaching them 1-2 cm.

In addition, to receive a more reflective useful signal from the antenna, a high-quality feed is needed. For offset one for direct focus the other (sold as a set).

On some satellites, broadcasting is carried out in two bands and it is not necessary to install two antennas to receive both. C + K converters have long been invented. But note that factory models for some reason are not too different from homemade ones.

C range is a godsend for a radio amateur - there is always a path to self-development.

Select the type of product you are interested in from the list:

satellite converter(English low-noise block converter - literally a low-noise monoblock converter) - a receiving device that combines an LNA (Low-Noise Amplifier) ​​signal preamplifier received from a satellite and a down converter (Downconverter), it is also a local oscillator (stabilized source high frequency, producing a sinusoidal signal), which is used to convert the frequency electromagnetic wave Ku (10700-12750 MHz) or C-band (3400-4200 MHz) into an intermediate frequency (from 950 to 2150 MHz), called the L-band, in order to transmit with the least loss over coaxial cable to the consumer. The converter is installed in the focal center of the satellite dish (on a remote bracket).

Principle of operation

Electromagnetic frequency oscillations satellite signal experience very strong attenuation in cable lines. That is why in the converter there is not only amplification of oscillations, but also frequency conversion. The input frequency is converted by subtracting (or adding) the local oscillator frequency. For each range, the converter uses its own local oscillator.

For C-band(3400-4200 MHz) use one local oscillator with a frequency of 5150 MHz or 5750 MHz. Since the width of the Ku-band (12750 - 10700 = 2050 MHz) does not allow you to simultaneously convert it to an intermediate frequency, since the width L-band significantly less (2150-950 = 1200 MHz), the Ku-band was conditionally divided into sub-bands:

• Ku-FSS (Fixed Satellite Services, 10.7-11.7 GHz) is usually called the “lower” - “Low”;
• Ku-DBS (Direct Broadcast Services, 11.7-12.5 GHz) received the designation "upper" - "High";
• Ku-BSS (Broadcast Satellite Services, 12.5-12.75 GHz) - Telecom subband.

In modern, so-called "universal" converters that allow you to receive the entire Ku-band, there are two local oscillators 9750 MHz and 10600 MHz. Single-heterodyne converters of circular polarization are also widely used. the local oscillator frequency of which is 10750. They are used to receive the signal of the NTV + and Tricolor TV operators. Switching between local oscillators is carried out using a 22 kHz tone signal from the control device (receiver satellite television- receiver) depending on the received subband.

Also, modern converters can work with different signal polarizations. Usually it is: linear (horizontal, vertical) or circular (left, right) polarization. Switching is carried out by changing the supply voltage of the converter - 13 or 18 Volts.

An important characteristic of the converter is noise factor(measured in dB), since when amplifying the useful signal, the converter introduces its own noise. The noise figure (NR) indicates how much the signal-to-noise ratio will deteriorate after amplification and frequency transfer. NR determines the sensitivity of the converter - the threshold value minimum level useful signal, below which the converter will no longer be able to register this signal due to its own noise. The smaller the value of KSh, the better. Good NR values ​​for cheap converters are 0.1-0.5 dB. In fact, the noise figures indicated by the manufacturers are always underestimated, due to marketing tricks. “Honest” NR values ​​are indicated on expensive (from $500) synthesizer (PLL) converters and cannot be better than 3-5 dB.