In the zone of uncertain reception of a television signal, in order to obtain a high-quality picture when watching television, it is necessary to install an external antenna on the mast, on the vibrator of which an antenna amplifier is additionally installed. Installing an additional amplifier provides a high-quality picture on the TV when the TV transmission tower is up to 100 km away.
Antenna amplifiers of the SWA line are widely used due to their high reliability and low price. They are produced for different channel ranges and different gains, from 34 to 43 dB in the decimeter range and from 10 to 15 dB in the meter range. The photo shows an amplifier type SWA-555 / LUX.
The antenna amplifier of the SWA television signal must be powered with a constant voltage of 12 V. There is a circuit solution that allows you to supply the television amplifier with a supply voltage via a coaxial cable simultaneously with the television signal. The photo shows how to connect a TV wire to the SWA antenna amplifier.
The central core is clamped with one screw, and the shielding wire is stripped of insulation, wrapped and clamped with screws using a strap. The main thing here is to prevent the screen wires from shorting with the central core. In this way, antenna amplifiers of any type installed directly on the antenna are connected.
On sale there are special power supplies - adapters with adapters that allow you to supply power to the antenna amplifier. The photo shows one of them. Connecting such an adapter is simple, a cable coming from the antenna is inserted into one coaxial wire, and a cable going to the TV is inserted into the second. The adapter itself is plugged into an outlet. It is impossible to confuse the wires when connecting; the coaxial wires coming out of the adapter have different connectors, which exclude an erroneous connection.
Power supply - adapter for antenna amplifier
If you open any power supply with an adapter, you will see a power transformer, four diodes, an electrolytic capacitor, a simple capacitor, a choke and a voltage regulator microcircuit.
All parts of the decoupling circuit, except for the power transformer, are installed on the printed circuit board.
Electrical circuit diagram of the power supply
for antenna amplifier with adapter
The power supply shown above in the photo - an adapter for powering an antenna amplifier is assembled according to a classic electrical circuit diagram. The mains alternating voltage of 220 V is supplied to the power transformer T1, which lowers it to 12-15 V. The diode bridge VD1-VD4 rectifies the voltage, the electrolytic capacitor C1 smoothes the ripples, after which a constant voltage of about 16 V is supplied to the integral voltage regulator DA1.
To eliminate video signal loss and loss of DC voltage, an LC filter is provided at the input of the television receiver, made on elements L1 and C3. Inductor L1 does not pass a high-frequency television signal to the power supply circuit, but without loss allows direct current to flow to the central core of the television cable coming from the television antenna amplifier. Capacitor C3 prevents the flow of direct current from the power supply to the input of the TV, but passes the TV signal without loss.
When you make your own power supply with an adapter, parts of any type can be used. Typically, the current consumption of antenna amplifiers does not exceed 150 mA, which is less than 2 watts, so the transformer for the power supply is suitable for any power with an output voltage of 15-18 V. The inductor can be made by winding on a dielectric base, for example, a strip of fiberglass 5 mm wide, 25-30 turns of enameled copper wire with a diameter of 0.1-0.5 mm.
Disadvantages of the presented design of the power supply with an adapter
The disadvantages of a power supply unit - an adapter of this design include the presence of an unshielded section of the central core of the television cable in the place of soldering into the printed circuit board, which, in the presence of interference, for example, from a working vacuum cleaner, can lead to interference with the video signal. The penetration of interference can be eliminated by installing an additional shield on the printed circuit board at the place where the wires are soldered.
Self-made adapter
An adapter adapter with wider technical capabilities can be made with your own hands from any antenna splitter crab. If you need to power a television amplifier and simultaneously connect several TVs to the antenna, then this is easy to do by supplementing the crab circuit with only three parts that will perform the decoupling function.
The device and scheme of the crab
The TV crab is a metal box with F-connectors. Inside, on the central terminals of the connectors, parts (high-frequency transformers) of a television signal splitter are soldered. A high-frequency transformer is in shape a ring or tube made of ferrite with a magnetic permeability of 600-2000, on which from 1 to 10 turns of enameled wire with a diameter of 0.2-0.3 mm are wound evenly spaced around the entire circumference.
In the photo of the crab, from which the back cover was removed, you can clearly see how the ferrite transformers are soldered to connect three TVs. This crab is assembled according to the electrical circuit diagram below.
All manufactured crabs are assembled according to the above electrical circuit diagram, there may be minor deviations - additional separating and filtering capacitors, chokes, and terminating resistors are installed.
How to make your own adapter
to supply voltage to the antenna amplifier
When making an adapter for supplying voltage to a decoupled antenna amplifier, I decided not to install an additional connector for connecting a power supply, but to use one of the connectors for connecting an F-plug. To do this, one of the transformers had to be removed, limiting the crab's ability to connect only two TVs.
As a result of the alteration, only two TV sets can be connected to the crab, and its scheme has changed.
It remains to install the LC filter in the crab and the adapter will be ready for use. Since the crab body is made of duralumin, it was necessary to connect the capacitor output to it through an additionally installed brass terminal, screwed to the adapter body with a screw and a nut with a shaped washer.
As a result of refinement, the electrical circuit diagram of the crab has acquired the following form. As can be seen from the diagram, the T1 transformer remained native, but a choke and two capacitors were added.
For better circuit matching, you can solder a 150 ohm resistor between the output pins XW2 and XW3. You can install the adapter in any convenient place, directly at one of the TVs, or, for example, at the cable entrance to the apartment. If you need to connect only one TV, then the transformer T1 can be removed, and the right terminal of the capacitor C1 can be soldered directly to the central terminal of one of the XW2 or XW3 connectors, to which you can connect the cable going to the TV.
Connecting the power supply to the adapter
Since I decided to connect the power supply to the crab through one of its F-connectors, to implement this idea, I had to make an adapter from an ordinary double wire coming from the power supply to a coaxial cable.
To do this, take a piece of antenna cable 5 cm long, cut one end of it and put on F-wrap. To the second end, as shown in the photographs, solder the wires coming from the power supply with a shift. The positive lead is soldered to the center core of the antenna cable.
If you don’t want to mess around, you can install a standard connector for connecting power supplies in the crab case and apply voltage to the antenna amplifier through it through an adapter made by yourself.
There are places where the TV signal is received in very low quality. In such cases, it is necessary to use an external antenna, on the vibrator of which the antenna amplifier is located. It allows you to amplify the signal even at a distance of 100 km from the tower.
Widely used amplifiers are SWA amplifiers. They have a low price and provide sufficient reliability. They have different gain and are designed for different range of channels. In the decimeter range, the gain is 34-43 dB and 10-15 dB in the meter. In the photo below you can see the amplifier model SWA-555/LUX.
The signal amplifier SWA operates from a constant 12 V supply. There is a circuit that allows you to apply voltage to the amplifier through a coaxial cable along with the signal. On the market you can find an adapter that is also a power supply that solves the problem. It is shown in the photo below.
Connecting the adapter does not require skills. We insert the wire that goes to the TV into one coaxial cable, and the antenna wire into the other. The adapter plugs into an outlet. It is not possible to confuse the wires, since there are different connectors at their ends.
By opening the power supply with an adapter, you can find a power transformer, simple and electrolytic capacitors, 4 diodes, a choke, a microcircuit that acts as a voltage stabilizer.
Everything except the transformer is located on the printed circuit board.
Electrical circuit diagram of the power supply with adapter
The adapter shown in the photo above is assembled according to the classical scheme. The alternating mains voltage of 220 V is supplied to T1 (transformer), which in turn reduces it to 12 V - 15V. VD1-VD4 (diode bridge) will act as a voltage rectifier. Capacitor C1 is used to smooth out ripples. After that, a constant voltage is obtained, the value of which is about 16 V. Then it goes to DA1 (integrated stabilizer).
LC filter is made on elements C3, L1. It is installed at the input of the receiver. It eliminates the loss of DC voltage and loss of video signal.
L1 (choke) prevents the high frequency signal from flowing to the power supply circuitry. At the same time, direct current freely flows to the central core of the TV cable, which comes from the amplifier. C3 (capacitor) prevents direct current from flowing from the power supply to the TV input. There is no signal loss in this case.
For self-manufacturing of the power supply, you can use parts of various types. Any transformer with an output voltage of 15-18 V can be used. This is due to the fact that the antenna amplifier does not exceed the current consumption of more than 2 W and 150 mA. As a choke, you can use a piece of dielectric, for example textolite, the width of which is 5 mm. From 25 to 30 turns of enameled copper wire are wound on it.
Disadvantages of the presented design of the power supply with an adapter
Among the shortcomings, one can note the presence of a section that does not have a screen on the central core of the television cable. This area is located in the soldering area with the printed circuit board. When operating machinery such as a vacuum cleaner, this may cause interference to the video signal. This can be avoided by installing an additional screen.
Self-made adapter
If you need an adapter - an adapter that has wide technical capabilities, it can be made at home from a crab - an antenna splitter. To power the amplifier and additionally connect several TVs to the antenna, the crab circuit will have to be supplemented with 3 details.
The device and scheme of the crab
A TV crab is a metal case with F-connectors. Inside it, high-frequency transformers of the tele-signal splitter are soldered. They are located at the center pins. In appearance, a high-frequency transformer is a tube or a ring made of ferrite. It has a magnetic permeability of 600-2000. Rounds of enameled wire are wound on top, the diameter of which is 0.2 mm–0.3 mm. They are evenly spaced around the entire circumference. The number of such turns can reach from 1 to 10.
Pictured is a crab. The back cover has been removed. As you can see, the ferrite transformers are soldered in order to connect 3 TVs. It was made according to the circuit diagram, which is shown below.
All crabs are made according to this scheme. It may have some deviations - installed chokes, resistors, filtering, separating capacitors.
How to make your own adapter
to supply voltage to the antenna amplifier
To make an adapter designed to supply voltage to the antenna amplifier, I did not install a connector for the power supply. I decided to use one connector to connect the F-plug. To do this, it was necessary to remove one transformer. The number of connected TVs has dropped to two.
As a result, the concept has changed.
Before using the adapter for its intended purpose, you should install the LC filter in the crab. The body of the crab is made of duralumin, so I made a brass terminal. It was fixed to the body with a screw and a shaped nut.
As a result, the scheme has changed slightly. Transformer T1 remained in its place, 2 capacitors and a choke were added.
In order to carry out circuit matching, it is desirable to install a 150 ohm resistor between the output pins XW3 and XW2. The adapter can be installed in any convenient place. Both at the cable entrance to the apartment, and near the TV.
If you use only one TV, T1 can be removed from the circuit. Solder the right terminal C1 (capacitor) to the central terminal of connector XW3 or XW2. The cable will be connected to the connector to which the capacitor will be soldered.
Connecting the power supply to the adapter
I wrote earlier that I want to connect the cable through the F - connector. Therefore, from the double wire that came from the power supply, I made an adapter for a coaxial cable.
Antenna designs
A. PAKHOMOV, Ph.D. tech. Sciences, Zernograd, Rostov region
Radio Magazine, 2000, No. 7
The author has already talked about SWA antenna amplifiers for Polish small-sized television antennas (as they are commonly called "Lattice") (for more details, see SWA Amplifiers for Lattice Antennas). Since then, many new models have appeared on the Russian market. This article introduces readers to their circuitry and characteristics.
In the 90s, in connection with the expansion of the on-air television network and the increase in the number of active channels, user interest in multi-channel television antennas, capable of receiving axis programs in the MB and UHF bands, without any switching, sharply increased. Since the middle of the decade, Polish small-sized television antennas ASP-4WA, ASP-8WA (CX-8WA) from ANPREL, DIPOL, ELECTRONICS and others began to enter the market, satisfying (to one degree or another) the requirements of such reception. Antennas quickly gained popularity, and quite a large number of them are now in operation.
Individual television antennas ASP-4WA, ASP-8WA are flat vibrator structures with a common mesh reflector screen. They are active, that is, they are equipped with electronic amplifiers installed directly on the antennas and powered by a drop feeder. Many characteristics of antennas, such as, in particular, gain and bandwidth, are obtained through the use of antenna amplifiers. Consequently, the quality of the reproduced television image largely depends on the parameters of the latter.
For active ASP antennas, different manufacturers produce a whole range of unified antenna amplifiers under various brands and numbers. Structurally, they are all designed in the same way: in the form of a small printed circuit board (approximately 60x40 mm) with surface-mounted microelements. The boards are manufactured using automated SMD technology and are quite reliable due to repeated control. Due to their characteristic design, these antenna amplifiers are called plate amplifiers.
The circuitry, parameters, shortcomings and repair of a large number of SWA antenna amplifiers are described in detail in. However, the companies that produce such amplifiers are improving their products, and many new models have now appeared: SWA. S&A, GPS, PAE, etc. Their parameters are undoubtedly of great practical interest both for owners who already operate antennas and want to improve image quality, and for those who decide to buy a new antenna. In addition, amplifiers can work with other types of antennas, for example, log-periodic, wave channel, etc. (provided that the input impedances are matched).
Antenna amplifiers have a number of characteristic parameters, which can be conditionally divided into two groups: general and individual. The general ones include: input and output resistances (300 and 75 Ohms, respectively), supply voltage (9 ... 15 V at nominal 12V), operating frequency-channel interval (1-68 TV channels, with rare exceptions). Thanks to the common parameters, the interchangeability of amplifiers is ensured.
However, to assess the quality of an amplifier, individual parameters that distinguish one amplifier from another, in particular, noise and amplification, are also important. Information about them is not always available, although recently it has been partially placed in the sales documentation for antennas. It is fully indicated in company catalogs, which are difficult to purchase even from companies that sell antennas in bulk.
In order to choose the right antenna amplifier, it is necessary to know two of its individual parameters: the noise figure and the reduced gain Ku. It is also highly desirable to represent the type of its frequency response.
Of paramount importance when choosing an amplifier is the noise figure: it should be as small as possible and certainly lower than that of the input stage of the TV. A modern antenna amplifier should have a noise figure of no more than 2 dB.
The second parameter (gain) is calculated according to the method described in, based on signal losses in the cable and passive splitters (if any). The antenna amplifier is selected according to the closest to the calculated value of the Ku coefficient. Its increase in excess of the calculated one gives an effect while reducing the noise level, otherwise the danger of self-excitation and overloading the amplifier with powerful signals from nearby stations only increases.
It is also necessary to take into account the dependence of the coefficient Ku on the frequency, which is determined by the actual frequency response of the amplifiers. Each of them has its own characteristic form of the frequency response. So, the SWA and PAE amplifiers have one smooth maximum (hump) at a frequency of approximately 600 MHz (the gain rise reaches 6 ... 10 dB). The S&A and PA amplifiers have a two-hump characteristic: the second gain increase by 3 ... 5 dB is located at a frequency of approximately 100 MHz, i.e., at MB. The type of frequency response allows you to select an amplifier depending on the reception conditions in order to improve stability and noise immunity by reducing the gain in non-working parts of the range. The gain specified in the documentation, as a rule, refers to the DM V range, at MB frequencies it can be significantly lower.
Most of the new amplifiers are assembled according to the traditional two-stage OE-OE scheme. Consider the circuitry, parameters and frequency response of some new models of amplifiers of various brands.
Amplifier SWA-555, the schematic diagram of which is shown in fig. 1 is a two-stage aperiodic RF amplifier based on T67 (BFG-67) or BFR-91A bipolar microtransistors. The first stage is broadband, without correction. There is a correction in the second stage: capacitor C5 in the current OOS circuit of the transistor VT2 provides a drop in frequency response at the lower frequencies of the operating range, and capacitor C4 in the voltage OOS circuit limits the gain at high frequencies and outside the operating band. The frequency response of the amplifier is shown in fig. 2. In general, the circuits of the SWA-555 and SWA-9 amplifiers are almost identical (the first one only lacks an LC filter in the power circuit and some ratings of passive elements have been changed). Therefore, the frequency response of the amplifiers are close. However, when using the BFR-91A low-noise transistor (Ksh = 1.6 dB) in the first stage, the SWA-555 amplifier has a lower noise figure.
S&A amplifiers have more complex equalization circuits in both stages. In models S&A-130, S&A-140, the schematic diagram of which is shown in fig. 3, a serial circuit L1C2 is introduced into the OOS circuit for the voltage of the cascade on the transistor VT1. Its resonant frequency is chosen such that the gain of the first stage decreases at the upper frequencies of the range, which contributes to the stability of the amplifier. To expand the correction band, the quality factor of the L1C2 circuit is reduced by resistors R1, R3. which provide the necessary constant current base of the transistor VT1.
The second stage is equipped with double RC circuits R6, R7. C6 and R7. C4, C5 in the emitter circuit of the transistor VT2, changing the frequency response in the low-frequency region. As a result, the characteristics of the amplifiers are double-humped, as shown in Fig. 4. The increase in gain at a frequency of 100 MHz reaches 3 ... 4 dB. The gap between the humps falls on the frequencies of 230...400 MHz, which are not used by terrestrial television channels. This form of frequency response improves the stability and noise immunity of the amplifier.
Other features of the S&A amplifiers include the use of a lightning protection diode VD1 at the input. Its efficiency is not very high, so it is recommended to ground the antenna.
In PAE amplifiers, as in S&A, LC correction is applied in both stages. In the RAE-45 amplifier, the circuit diagram of which is shown in fig. 5, it is provided by two serial circuits L1C3 and L2C5, included in the OOS circuits for the voltage of the first and second stages, respectively. In addition, affect the formation of the frequency response and capacitors C2, C8. As a result, the hump on the frequency response of this amplifier is sharper, with a sharp drop at frequencies above 700 MHz, as can be seen in Fig. 6.
It makes no sense to consider PA amplifiers in detail, since they are similar to S&A amplifiers, with the exception of using a coil instead of a VD1 diode at the input. The frequency response of the RA and S&A amplifiers is approximately the same.
The GPS models are similar to the SWA-455, SWA-555 amplifiers and differ only in the values of the corrective elements in the second stage. By increasing the capacitance of the blocking capacitor in the emitter circuit of the second transistor, an increased gain was achieved in the frequency range of 100...400 MHz.
In some new models of amplifiers, an additional circuit is connected to the emitter of the second transistor from series-connected tuning and constant resistors and a capacitor (shown in Fig. 1 by a dashed line). In this case, the trimmer resistor can change the gain in the lower frequency range and, consequently, the frequency response of the amplifier. Unfortunately, the value of such a correction regulator is small, since the amplifier is difficult to access when the antenna is raised.
The analysis of the circuitry and frequency response, of course, is not complete, since, in addition to corrective circuits, the frequency response is affected by the relative position of parts, mounting capacitance, the presence of strip lines, etc. Nevertheless, according to the author, it is sufficient for the correct choice of amplifier according to the type of frequency response, and in some cases for self-tuning by selecting corrective elements.
The following practical recommendations emerge from the analysis. The real form of the frequency response of the SWA and PAE amplifiers is such that they are best used mainly for receiving remote stations in the UHF range. at which the amplifiers have maximum gain. Due to the reduced gain in the MB region, such amplifiers (especially PAE) are more stable and better protected from interference at these frequencies.
To receive weak MB signals, preference should be given to S&A, PA and GPS amplifiers, which have increased gain on the MB. This is especially important, given that small-sized ASP antennas have very little intrinsic gain on the MB band: at a frequency of 50 MHz, for example, the ASP-8WA antenna does not exceed 1 dB.
Main parameters of new SWA models. S&A. PA, GPS, PAE (operating frequency interval f, noise figure Ksh and gain factor Ku) taken from the Internet. as well as company catalogs, are presented in the table placed here. In case of discrepancies in information, the worst values are included in it. Obviously, some new models have achieved some noise reduction (up to 1.5 dB), however, there are still quite "noisy" amplifiers with NR1 equal to 3 ... 3.9 dB (SWA-31. SWA-32, S&A-110. S&A-120. RA-10), which are not recommended.
Manufacturers have not yet managed to achieve a significant improvement in the noise characteristics of most amplifiers. The best previous models SWA-7, SWA-9 had a Ksh = 1.7 dB. It remained approximately the same for new amplifiers or was slightly reduced, with the exception of the SWA-47(AST), SWA-49(AST) models. This is primarily due to the fact that the circuitry and the transistors used have not changed: the same microwave transistors T67, V3, 415 with a limiting frequency of 7.5 GHz and a noise figure of up to 3 dB are used in the input stages, and only occasionally - less "noisy" BFR-91A.
It should be noted that the characteristics of the amplifiers are affected not only by the type of the first transistor, but also by the operating mode. The level of intrinsic noise, the gain and the value of the active component of the input conductivity, which affects the degree of input matching, depend on its collector current.
In most antenna amplifiers, the VT1 transistor operates at a collector current of 1 "= 8 ... 12 mA. This allows you to get a fairly high gain and good matching with the input transformer T1, but not optimal for low noise floor. Although the dependences Кsh=f(Iк) of the used microchips are unknown, but, as a rule, for microwave bipolar silicon transistors, the minimum noise level is observed at a collector current of 2...5 mA. Therefore, there is a possibility that by reducing the collector current of the transistor VT1, the noise level can be reduced while maintaining good matching at the input. This is indirectly confirmed by the fact that for PAE amplifiers (only for them) the current of the first transistor is reduced to 4 ... 5 mA. due to which, with the same transistors, a significant reduction in the noise level was achieved: according to information from the Internet, the Ksh coefficient for these amplifiers reaches 0.8 ... 1 dB.
As noted in , many high gain SWA antenna amplifiers are prone to self-excitation. This is explained by. that it is quite difficult to ensure the stability of a two-stage aperiodic RF amplifier assembled according to the OE-OE scheme in the frequency band up to 900 MHz. It would seem that a further increase in the number of cascades does not make sense, since it is practically impossible to achieve stability in this case. Nevertheless, amplifiers assembled on four transistors appeared on the market. Intrigued by this fact, the author purchased the SWA-2000/4T amplifier. Its circuit diagram, drawn up on a printed circuit board, is shown in fig. 7.
An analysis of the circuitry of this amplifier showed that it was assembled according to the usual scheme on two transistors VT1 and VT2, connected with an OE. The input signal is fed to the base of the transistor VT1, amplified in a two-stage track and removed from the collector of the transistor VT2. acting through the transition capacitor C9 in the coaxial cable. Additional transistors VT3 and VT4 are included in the active circuits that set the bias voltage at the bases of transistors VT1 and VT2. Since transistors VT3, VT4 do not amplify the useful signal, low-frequency and cheap 3F chips are used for this purpose.
Obviously, with such a construction, the characteristics of the SWA-2000/4T amplifier cannot in any way significantly exceed the parameters of two-stage amplifiers with similar correction (SWA-7, SWA-9, SWA-555, etc.), which was confirmed by comparative tests.
Summarizing, we come to the following conclusions. Firstly, many of the new amplifiers repeat the circuitry and, accordingly, the characteristics of the old models. At the same time, a solid number of a new development does not at all indicate its higher quality. For example, the SWA-555 amplifier in terms of parameters and circuitry is the same SWA-9 amplifier. The same applies to amplifiers assembled on four transistors.
Secondly, among the new amplifiers there are models with really improved characteristics, which also implies the possibility of improving the quality of reception. In terms of noise parameters, the SWA-47 (AST), SWA-49 (AST) amplifiers can be recognized as the best, and also, judging by information on the Internet, PAE-type amplifiers.
Thirdly, the replacement of the antenna amplifier will lead to a positive effect only if a new model with a lower noise level, the calculated gain value and a suitable frequency response is used.
In conclusion, let's say that manufacturers develop models of antenna amplifiers quite quickly and it is possible that by the time the magazine with this article is published, new, improved amplifiers will probably appear. In any case, the criteria for determining their quality and recommendations for selection, discussed here and in, do not change.
LITERATURE
1. Pakhomov A. Antenna amplifiers SWA. - Radio. 1999. No. 1. p. 10-12.
2. Nesterenko I. I., Zhuzhevich A. V. Choose the antenna yourself. - M.: Solon. 1998.
3. Semiconductor devices. low power transistors. Reference book (A. A. Zaitsev, A. I. Mirkin, V. V. Mokryakov, etc.). Under the general editorship. A. V. Golomedova. - M. Radio and communication, 1989.
The SWA and LSA antenna amplifiers are not independent devices, unlike external amplifiers such as Alcad. They are an electronic amplification board and need a power supply and a protective cover.
are used in lattice antennas ASP-4, ASP-8, which are often called Polish antennas. The gain of such antennas without an amplifier is small, and its receiving properties are mainly determined by the installed amplifier.
Antenna amplifiers swa have an input impedance determined by the design of the antenna 300 ohms, an output impedance of 75 ohms for connection to a television receiver, use a supply voltage from 9 V to 15 V and are designed to amplify frequencies of 49 - 790 MHz.
Amplifiers
What's happened grid antenna? Array antennas, sometimes referred to as grid antennas or screen antennas, are a flat vibrator structure with an overall grid screen that acts as a reflector. Antenna amplifiers swa are installed directly on such an antenna and are fed with direct voltage through the antenna cable. Structurally, the amplifiers for lattice antennas, manufactured by different manufacturers, are made in the same way, in the form of a small board measuring 60 x 40 mm with surface-mounted smd elements.
swa amplifier installed in outdoor antennas, arrays, grids or as they say "Polish antennas". Depending on the distance to the transmitting television center, various models of the amplifier board are used, which have different gain factors and allow receiving television programs at a distance of 0 to 150 kilometers from the transmitter.
Antenna amplifiers characteristics
What parameters affect the quality of amplifiers? To evaluate the quality of the swa amplifier, that is, the quality of the image on the TV screen, the gain and noise figure parameters are very important. The noise figure should be as low as possible, and the gain should not be maximum, its value should not be more than such that the value of the signal entering the TV input is in line with the norm.
The summary table shows the technical parameters and characteristics of swa antenna amplifiers, their modifications and analogues sym, lux, turbo, aws, wa, s&a, pa, gps, pae, ts. Noise figure and gain are given in dB, recommended distance to TV center in km.
| SWA amplifier board | Coefficient MV gain, dB |
Coefficient UHF gain, dB |
Coefficient noise, dB |
Range up to telecentre, km |
|---|---|---|---|---|
| sym 01 | 0 | 0 | 0 | 0-10 |
| swa 1 | 2-5 | 8-14 | 2.8 | 3-10 |
| 1 lux | 13-14 | 13-23 | 2.7 | 5-15 |
| 2 | 15-18 | 20-25 | 2.8 | 10-20 |
| 3 | 2-6 | 20-28 | 3.1 | 10-30 |
| 4 lux | 0-8 | 29-35 | 3.0 | 20-45 |
| 5 | 5-10 | 25-31 | 3.1 | 10-40 |
| 6 | 5-10 | 25-30 | 3.1 | 10-40 |
| 7 | 5-6 | 25-32 | 3.0 | 30-70 |
| turbo 7 | 10-17 | 31-38 | 1.9 | 30-70 |
| 9 | 9-11 | 21-31 | 3.1 | 30-70 |
| 10 | 7-12 | 22-27 | 1.9 | 8-30 |
| 14 | 1-16 | 28-37 | 2.8 | 30-70 |
| 15 | 3-11 | 35-43 | 2.8 | 30-80 |
| 16 | 34 | 34 | 1.8 | |
| 17 | 11-15 | 35-42 | 2.9 | 30-100 |
| 18 | 32 | 38 | 1.8 | |
| 19 | 11-20 | 33-42 | 2.9 | 30-100 |
| 21 | 10 | 16 | 2.2 |
| SWA amplifier board | Coefficient MV gain, dB |
Coefficient UHF gain, dB |
Coefficient noise, dB |
Range up to telecentre, km |
|---|---|---|---|---|
| 31 | 22 | 28 | 3.0 | |
| 41 | 30 | 33 | 1.5 | |
| swa 49 | 2-16 | 26-36 | 3.1 | 30-50 |
| 555 lux | 10-15 | 34-43 | 2.2 | 50-100 |
| 10-13 | 34-45 | 2.3 | 50-100 | |
| 999 | 10-13 | 33-45 | 2.9 | 80-120 |
| 5555 | 10-13 | 34-45 | 2.9 | 80-120 |
| 7777 | 4-13 | 34-45 | 2.8 | 100-120 |
| swa 9999 | 10-20 | 35-47 | 2.9 | 100-120 |
| 2000 | 13-18 | 40-47 | 2.8 | 100-130 |
| 3501 | 11-18 | 40-48 | 2.0 | 100-130 |
| swa 6000 | 20-52 | 50-52 | 1.2 | 80-140 |
| 9000 | 0-28 | 10-40 | 1.5 | 20-100 |
| 9001 | 12-16 | 42-45 | 1.5 | 100-150 |
| 9999 | 15-28 | 42-50 | 1.7 | 70-120 |
| aws 14 | 0-20 | 26-39 | 2.5 | 10-50 |
| 110 | 12 | 12 | 3.5 | |
| 120 | 22 | 22 | 3.9 | |
| 130 | 28 | 34 | 1.7 | |
| 140 | 28 | 34 | 1.7 | |
| pa 2 | 12 | 12 | 3.5 | |
| pa 5 | 28 | 34 | 1.7 | |
| pa 9 | 28 | 34 | 1.7 | |
| pa 10 | 22 | 22 | 3.9 | |
| gps wa-041 | 32 | 1.7 | ||
| gps wa-042 | 32 | 1.7 | ||
| gps wa-501s1 | 32 | 1.5 | ||
| gps wa-501s2 | 34 | 1.5 | ||
| gps wa-501s3 | 34 | 1.7 | ||
| pae-14 | 25 | 30 | 1.5 | |
| pae-42 | 25 | 30 | 2.5 | |
| pae-43 | 26 | 32 | 2.5 | |
| pae-44 | 26 | 32 | 2.7 | |
| pae-45 | 28 | 34 | 2.2 | |
| pae-65 | 24 | 28 | 2.5 | |
| pae-65ts | 24 | 28 | 1.7 |
Purpose of the antenna amplifier lsa
Antenna amplifiers LSA produced to repair failed popular active television antennas Locus. Active antennas fail as a result of a powerful electromagnetic discharge during a lightning strike, malfunctions of the power adapter, due to aging of the elements, due to a violation of the sealing of the protective mounting box and wetting of the circuit elements.
Replacing the standard Locus amplifier with an lsa amplifier
Antenna amplifier LSA 417(LSA 020) is used to replace the failed amplifier models L 025.09, L025.12, L025.62 and other Locus series 25 antenna models. It is used for models manufactured after 2007. A characteristic feature is the presence of plastic guides in the amplifier mount. The Locus 025 series of antennas is equipped with one amplifier and one LSS-422 matching board, which has no active elements and which practically does not fail.
In older models of Locus L 025 antennas, LSA 417 amplifiers are used with a different method of mechanical fastening and do not differ in circuitry.
Antenna amplifier LSA 421(LSA-071) is designed for broadband amplification of television signals and is used in antennas Locus L012.20, L023.09, L023.12, L024.09, L108.00.
The amplifier has a noise figure of no more than 2 dB, consumes a current of 20 mA from the power supply at a supply voltage of 12 V.
Antenna amplifier LSA 416 is used for replacement in indoor antennas Locus L405.05
In television antennas Locus 024.09 and Locus 024.12, instead of two LSA 419 amplifiers, an LSA 839 amplifier board is available.
Answers to questions about SWA and LSA amplifiers
How to connect the "Polish" antenna correctly
Please tell me how to set up the TV and how to properly connect the Polish antenna (you need an amplifier). Therefore, when buying, it is said that T2 is on the TV. But when setting up, there is not a single channel. 12/14/2018, Ukraine, Dubensky district, p. Tarakanovo.
For the antenna to work, it is necessary to make the correct choice of the SWA amplifier model, fix it on the antenna and connect it to the power supply unit through a separator. In addition, the design of the antenna should be located at the point of best reception and directed to the district television transmission tower.
Swa 49 which is good in terms of practical noise performance.