Redesign of the converter for circular reception. Equipment for digital television is what you can buy in our store

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

For clarity, let’s take another look at the table of transponders for 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 have marked the required columns in green.

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

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

Quite often, at least at the time of writing this topic (since in the C band the signal comes mainly from old satellites, and it is used less and less), both of these frequency ranges may be present in the transponder tables of one satellite. That is, both the range is C and the range is Ku.

In this case, you will have to choose which transponders suit you best. This means, accordingly, the converter will be either “Ku” 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 have a diameter of 1.5... meters (since, for the C-band, an antenna of a larger diameter is needed). As a rule, dual-band satellite converters are much more expensive.

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

Both of these polarizations are combined in one type of converter - a 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, then you need to use a circular converter. Or another way to 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) polarization.

In the case when you want to receive a signal with both linear and circular polarization, you will 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 the other ().

DiSEqC switch - Serves for remote switching between different receiving devices. For example, between two, three... (etc.) satellite antennas, 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 polarization, 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. At the time I installed satellite dish, there were almost no such transponders (meaning open Russian-language ones, with circular polarization), well, perhaps “NTV+”, but now, at the moment (i.e. at the time of writing this page), it was already working with all its might quite popular, the Russian project "Tricolor TV", broadcasting several program packages from one transponder (one free, and paid START and NIGHT), in this case this converter, Ku band, with circular polarization, would be suitable. In any case, at that time, I needed a universal linear one. On top of that, my receiver did not support the encodings in which channels with circular polarization were transmitted.

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

As I already mentioned, by installing satellite dish, I not only wanted to watch the satellite TV channels themselves through the receiver, but also, by installing a DVB card in my computer, have access to the satellite Internet, thereby making the most of the opportunities that now presented themselves.

Therefore, when using satellite dish, I needed to output from 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, with one irradiator (Photo 7).

Photo 7 Satellite converter with two independent outputs.

In principle, it was possible to go another simpler way, leaving 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's what.

Photo 8 Splitter - signal splitter.

The advantage of such a splitter would be: firstly, the relatively low price of such an upgrade (at the time of writing this page), about 80 - 150 rubles, secondly, there is no need to change the converter, risking losing the settings satellite dish, and thirdly, simple manipulations during installation.

Now, as for the shortcomings. To figure this out, you need to know a little about the operating principle of the converter itself, or rather, the circuit diagram of its power supply directly in this case.

Converter power supply

Imagine some kind of electronic device, for example, a pocket receiver. Without what will it not work, even if the entire electronic circuit is working? The answer here suggests itself. Of course, if we don't put batteries in it. That is, we will not provide it with 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, we’ll turn the tuning knob or use the toggle switch to switch to another range. What about the converter? After all, you can’t climb onto a satellite dish to twist or switch anything.

So the developers came up with the idea of controlling the converter remotely, using the same cable through which the satellite signal travels. So, in order to control the switching of the type of polarization, the converter is supplied with power of different voltages, as if in 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 power compartment. Let's say one radio station will be broadcast if the receiver has four batteries, and another if there are six.

In a converter with linear polarization, if vertical (V) polarization is used, then a power equal to 13...14 volts is supplied to it, 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 for two receiving devices through a splitter, so to speak, what is its essence.

The point here is that the satellite converter can only be powered by one voltage at a time. That is, either 14 volts or 18 volts. This means that the polarization can only be either vertical (V) or horizontal (H). And this is 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 (or on a second receiver), you can simultaneously use vertical polarization, although the TV channel may be different.

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

The advantage of a converter with two independent outputs is that it does not matter which output has which polarization (in this case, linear “V” and “H” are meant). The disadvantages include the rather greater weight than a converter with one output, and of course the higher price. At that time, it cost me 980 rubles (whereas for a converter with one output, I then spent 270 rubles).

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

Well, all that remains is 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 the option I gave for assembling the satellite converter mount by left-clicking on the image (Photo 9).

Photo 9 Converter on a holder satellite dish.

Parameters of satellite converters

(marking of satellite converters)

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

Converters for installations to offset satellite dish

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

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

For greater clarity, let’s enlarge the image of the converter markings (Photos 4 and 5).

Judging by the logo, the converter was manufactured by a fairly popular satellite equipment manufacturer at the time, 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.

Type of polarization - Circular (right and left), and Linear (vertical and horizontal).
Frequency range - C or Ku.
Noise figure - the higher this figure, the lower the quality of the received signal.
Gain coefficient - the higher this coefficient, the more the received signal will be amplified (it should be taken into account that both the signal itself and the noise are amplified).

Below in the image of the converter markings (Photo 6 and Photo 7), I have highlighted some values in 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 high noise figure, for example 0.3 dB (or the completely outdated 0.6 dB), they are usually cheaper, but... I would not skimp on this parameter (tested by practice).

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

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

Note: The manufacturer decided not to indicate such a parameter as “gain” on the converter labeling.

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

(marking of satellite converters)

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

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

We will need the remaining parameters when setting up the satellite receiver (receiver), where I will continue discussing converters in more detail.

Now, install to satellite dish the converter you have chosen, and it’s time to stop at choosing 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 receiving a specific frequency spectrum, that is, again, a range.

Satellite converter

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

You may come across the following designations for converters, LNB or LNBF - in principle, the correct name is both. But if you consider that converters going to offset satellite dishes, have an integral housing with a feeder (Photo 1), then it would be more correct to use the name - LNBF (LNB - converter, + Feeder - 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 usually assembled before mounting on satellite dish. In this case, the correct name would be LNB + F (LNB - converter, + Feeder - feeder).

Satellite converter ranges

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

Ku-band satellite converters are more common since the diameter satellite dish, when using such a converter, is usually from 0.5 to 1.2 meters. When receiving the C-band, the antenna dimensions are required to be 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 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; we will consider how to calculate its more accurate parameter 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 a radio signal, differ in the type of signal polarization. Moreover, two types of polarization can be present in one converter at once.

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

Linear universal satellite converter

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

Linear horizontal(H - Horizontal).

Linear vertical(V - Vertical).

Circular satellite converter

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

Circular right (R - Right).

Circular left (L - Leftl).

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

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

Selecting the type of satellite converter is, so to speak, an individual approach, and each user chooses it in accordance with their requirements. That is, according to the type of signal that it 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...).

I will also dwell on some of the use of satellite converters, as well as some aspects of the principle of its operation, in the section - installation and configuration of a satellite dish, that is, during the installation itself and satellite dish settings.

To begin choosing the satellite you need, or rather, what it broadcasts, it’s not enough to know the configuration satellite antennas. You also need to learn to understand the table of 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 more simply, what set) we can receive a signal from this satellite.

Linear and circular converters are designed in the same way. In the depths of the waveguide there are small antennas, 2-3 mm in size, horizontal and vertical. The circular converter differs only in that at the beginning of the waveguide, in front of these antennas, there is a plastic plate that “straightens” the twisted wave. Therefore, if you have a universal converter, and you want to receive Eutelsat W4/W7 36E (which transmits the signal in circular polarization), then you need to do the following:

you need to remove the protective cap on the converter and if it is the cold season, then it is better to remove the converter, bring it into the room and wait until it warms up and becomes elastic. Otherwise, when opening the cap, it may crack in the cold. But even if this happens, don’t worry, then you can put a transparent plastic bag over it and seal it with tape. To make the removal process easier, you can “steam” the lid in boiling water. There is a rubber ring inside the cover that serves to seal the waveguide. Don't lose it!

To make the process easier, it makes sense to remove the protective housing from the LNB. The protective housing consists of two plastic halves connected with latches.
Any metal ruler works well for pressing latches. It is not recommended to press hard - you can break the latches.

The next step is to cut out the depolarization plate. The shape of the dielectric does not matter, the main thing is that it is flat and at an angle of 45. Cut it out of plastic about 2-3 mm thick. a “rectangle” plate 40 mm long (if there will be reception only in circular polarization).

You can cut out 2 plates from a bank card, the width of the waveguide diameter and 40mm in length, and insert them together (to make it thicker). Or 0.5-2cm (if you want to make it universal and circular at the same time). The width of the plate is equal to the inner diameter of the converter waveguide.
Next, we install the plate at an angle of 45 degrees (from 8 o’clock to 14 o’clock) to the pins almost all the way into the waveguide (just make sure not to bend the pins in the waveguide! Insert about 5-10mm short of the pins).

If the converter is already installed or is directed with the connector for connecting the cable downwards, then the plate will look like THIS (Front view. The cable goes down to the Dysic/receiver. RED shows how the plate should be positioned CORRECTLY):

Here's what you shouldn't do:

but if you did this, then when searching, instead of R we set H, instead of L we set V.

If you have converted a UNIVERSAL (dual-band converter) - then you DO NOT need to change the local oscillator frequency to 10750. Just set UNIVERSAL and that’s it.

If that doesn't work, check the following:

plate 40 mm long
The material is plastic from a SIM card or similar (but other material such as thin plexiglass, a transparent student ruler, an opaque ruler, etc.)
Drown it almost to the very bottom (not reaching the pins inside about 4-10mm)
Try two 40mm long plates folded together
You can, if you want, try a plate of different lengths (30-50mm) and from different materials. Insert it at different depths. Focus on the maximum signal.
If the signal drops when closing the converter cover, the plate can be shortened or made thinner
There is NO NEED to change the local oscillator frequency in the tuner from 10600 to 10750
In the tuner, select the converter type UNIVERSAL (usually the default)
Look carefully at the drawings and photos above
I recommend setting 36e to 12265 H (L) 27500 3/4
By turning the converter a few degrees you can achieve an additional increase in signal level. The angle and direction depends on the receiving location. Don’t overdo it with the turn (don’t forget to check the level on different transponders and on L and R)

Satellite converter universal and with circular polarization - a device or device for receiving a signal from a satellite, combines two devices (functions), a signal converter from one range to a specific frequency and a signal amplifier.

Kinds.

There are a large number of different convectors. They differ in local oscillator frequency, type of polarization, noise level, and operate in different frequency ranges.

Let's consider two types of converters operating in the Ku band. Converter data is the most widely used.

1. Universal converter with linear polarization.

One of the most popular converters. Receives programs broadcast with vertical and horizontal polarization from various satellites. For example - Amos 4w, Astra 4.8E, Hotbird 13E and others.

2. Circularly polarized.

Used to operate in the Ku-band 11700-12750 MHz. Exactly like this , with circular polarization, is needed to receive programs from the providers NTV Plus and Tricolor TV. This converter, in appearance, does not differ from the “universal” one, but has a built-in dielectric plate, the so-called. depolarizer and one local oscillator with a frequency of 10750 MHz. The name of the converter contains the inscription Circular Single.

TWIN .

This converter is used on a satellite dish to view television content independently on two TVs.

QUAD .

The use of a Quad converter is due to the need for independent viewing of satellite programs - up to four TVs.

Characteristics - Ku band.

Satellite converters are characterized by:

First of all, the noise factor

Local oscillator frequency (9750 MHz and 10600 MHz - universal converter with linear polarization. 10750 MHz - for converter with circular polarization)

For the KU range - a sub-frequency range (lower, upper, Telecom).

Type of signal polarization (horizontal, vertical, circular - left and right)

Number of outputs

What is inside?

When installing satellite dishes, customers sometimes ask, “What's inside?”

Let's take the device apart and see what's inside.

Few people know: the first Simple Satellite came off a carrier on October 4th, which differed little from an intercontinental ballistic missile. The new product was a derivative of a powerful weapon, with the help of which N. Khrushchev wanted to show Kuzkin his mother to the enemies of socialism. The Americans were frightened by Gagarin's flight and immediately sent an expedition to stake out the Moon, where alien bases are located on the far side. Jokes aside, the arms race went far, soon space became crammed with spy aircraft. To prevent the satellites from interfering with each other’s work, it was decided to introduce uniform standards based on territoriality and purpose. Today we will look at how converters for satellite dishes support the requirements of the standards, and why this is needed.

Frequency division of converters

The year 1977 was marked by the meeting of an international conference that adopted rules for systematizing satellite activity. Naturally, the procedure was preceded by numerous studies by the participants. The passage of waves of different lengths into the atmosphere was studied. Just kidding, punch through the air to the soil from space! Geostationary satellites do not hover so low above the Earth. Why do they float? The earth rotates tirelessly; in order to compensate for the movement, the satellite has to move after its orbit. The speed is enormous, because in 24 hours it must make a full revolution.

The radius of the Earth is approximately 6370 km. The shape of the planet is not round, not even elliptical. Experts say: it looks more like a pear, tapering towards the North Pole; it simply lacks a suitable body of geometry. It is believed that the shape of the earth is the geoid. Now we will give the value of the orbital radius; understand, the counting is carried out from the conditional center of the earth, located at the intersection of the equatorial plane and the axis connecting both geographical poles. The planet's center of mass is located in a different place; geographic poles should not be confused with magnetic poles (indicated by a compass).

In order for the satellite to begin to rotate around the Earth, it is necessary to inform the object of the First Cosmic Velocity. The device must move in orbit, working out the angular velocity of the planet's rotation. Make one revolution every 24 hours (23 hours 56 minutes). Smart heads have calculated: the orbital radius should be 42,160 km at an altitude above sea level of about 35,790 km. Because the Earth rotates on an axis through the poles, the only orbit possible is geostationary satellites. Located strictly above the equator. To make a satellite in another orbit immobile relative to the Earth, one will have to constantly make great efforts and spend a host of resources.

This does not mean that spacecraft hanging above the equator at an altitude of 35,790 km are deprived of human attention. Special stations constantly monitor the position and orientation of the satellites, making adjustments to the movement if necessary. The corrections are so small that the fuel is enough for the spacecraft to operate for many years. Now we know why the plates of the Northern Hemisphere look south. Not strictly along the meridian, but in the direction of the equator.

Since the prime meridian passes through the axis of the passage instrument of the Greenwich Observatory, located in Great Britain, Russia lies in the Eastern Hemisphere. The list of satellites broadcasting in this space is given by Wikipedia. Not everyone will be visible from any point on the earth’s surface at the same time; choose your provider carefully. Otherwise, you won't be able to watch TV.

Why do you need a converter for a satellite dish?

So, a satellite has been selected, visible above the horizon at the antenna installation point, it’s time to watch TV. The Commission, which met in 1977, divided the broadcast bands into sub-bands. Here is a partial list:

L: 1.4 - 1.7 GHz.
S: 1.9 - 2.7 GHz.
C: 3.4 - 7 GHz.
X: 7.25 - 8.4 GHz.
Ku: 10.7 - 14.8 GHz.
Ka: 15.4 - 30.2 GHz.
K: 84 - 86 GHz.

Some frequencies are used by the military. Television broadcasting uses the C and Ku bands, and in Europe the latter is used mainly; in Russia we will find both. Therefore, the first thing we will say about satellite antenna converters is that they come in different ranges. Concerns geometric dimensions. It should be noted: the plates of different ranges do not have the same diameter (ideal). The wavelength is shorter (higher frequency), the dimensions of the satellite dish are more modest. Caused by the peculiarities of focusing electromagnetic waves by paraboloids (plate shape).

Stores sell a complete set: a satellite dish plus a converter; there are many who like to embrace the immensity and try to place two inhomogeneous devices for receiving radio waves side by side. Let us briefly describe the reason. There are two satellites hanging, one broadcasts in the C band, the other - Ku. Using the experience of using a toroidal antenna, amateurs place two converters in the desired way so that each receives a signal from one point in the sky, located the mentioned spacecraft.

The plate is heading towards the equator. The criterion is the maximum satellite signal at the output. Each converter is adjusted as needed. Move along the guide relative to the plate until reliable reception is achieved. If the angle of linear polarization does not match (NTV by), the satellite antenna converter is rotated properly. For circular polarization, the orientation of the converter relative to its own axis does not matter.

To carry out operations, special devices (Satellite Finder) are used to record the dish signal and evaluate reception. The received information from both converters is summed up by matching devices and fed to the detector input. The screen displays a table of satellites; you can obtain information on the received signal of each. If necessary, the database is replenished with its own settings.

A converter for a satellite dish is a device for receiving an electromagnetic signal emitted by a satellite. The plate will serve the purpose of focusing the waves at the input of the converter. The maximum amplitude of the electromagnetic field is reached in this place. Installing two converters for a satellite dish on one dish is based on the fact that rays coming from the same direction are collected by the focal plane. The converter for the satellite dish looks directly at the center of the dish, contained in the said plane. What if one spacecraft broadcasts on different frequencies? The shelves are crowded with an abundance of combined converters of both ranges.

When tuning your antenna to more than one satellite, keep more than just frequencies in mind. We mentioned in passing above: is the polarization of the signal circular or linear, but how is this fact taken into account by the converter side? Simply brilliant. The difference is limited to a small design detail.

Design of satellite antenna converters

Any converter, regardless of frequency or polarization type, is characterized by a similar design. Here are the main details:

a piece of round waveguide, one end is tightly sealed, the second will serve to receive radio waves;
bell of the open end of the waveguide to improve directivity properties and match all frequencies;
an electronic unit through whose antennas the signal is received.

The converter is represented by a piece of pipe equipped with a socket and a small metal box at the bottom, tightly attached. Antennas are pins protruding deep into the waveguide. The structure is covered with plastic, there is a round lid in front, tightly pressed onto the socket. Now polarization.

It turns out that the satellite antenna converter device always accepts only linear polarization. If the satellite emits circular radiation, the waveguide is supplemented with a plastic plate at an angle of 45 degrees to the pipe axis. Depolarization is achieved. Hobbyists noticed a small detail and began to modify the design according to their needs. The satellite antenna converter is configured for the type of polarization by installing/removing the dielectric plate. Can be made from a plastic card.

It becomes possible to use converters in toroidal antennas. The plate simply tilts 45 degrees in the other direction (reflection changes the circular polarization to the opposite one). To open the sealed plastic lid, boil it with boiling water, and then attempt to remove it. The product can be put back on without any problems. Before checking the satellite dish converter for functionality, take the trouble to check the installation angle with an ordinary protractor. If the outcome is successful, we will secure the result of the work with a small amount of sealant that has adhesion to plastic and metal.