The online store "RadioExpert" specializes in the realization of various radiosters, in particular those intended for the operation of civilians. On the resource you can buy a radio, radio stations, amplifiers and other products of this type.
Amplifiers of ultrashort waves
VK power amplifier is designed to work in frequencies of over 100 MHz. It is waves with a similar frequency are ultrakotov. It is worth noting that not all frequencies of this type are publicly available. Some of them are allowed to enjoy only the emergency situation (146 - 200 MHz frequency of urban services). Many, for example, 145 MHz are publicly available, but many and those that are used to communicate with the ISS, satellites, marine courts, aircraft, etc.
Thus, the VHF power amplifier may be required by both ordinary citizens and various organizations and even government services. If you want to buy a power amplifier in the radioEEKSPERT, we recommend carefully examine the price before making a choice. If necessary, you can always contact specialists. Online managers will advise you and help to order a product of interest.
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The main advantages should be attributed to:
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As usual, first prehistory. I decided to somehow get the amplifier to my favorite VHF range of 1200 MHz. But give 16-20 thousand rubles for ready-made amplifiers (for example, Tokyo Hy-Power, ProCo, etc.) I was sorry for me. And indeed, the thing that is needed 1-2 times a year at a field-day competition, somehow does not combine with the amount of $ 700.
And I decided, it means to make an amplifier myself. But the word "himself" does not mean "completely from 0", but on ready-made modules Mitsubishi ra18h1213g. It was, of course, to completely collect with "0" on the transistors or lamps, but now in the yard is not the 1980s year, in the end!
Homemade, do not be offended! I myself am a self-dealer, Dailed everything - from the first detector receiver in 1985 and to microprocessor control units and frequency synthesizers lately. But to do what you can buy is easily inexpensive - I consider it quite a big stupidity and the loss of precious time, which is quite small and which can be spent with b aboutnext benefit.
It seems to me that at present, the most optimal ratio of the results to costs is obtained in the manufacture of an amplifier at 1200 MHz by using something ready.
And so, with the aim of reworking at 1200 MHz in the Japanese auction, the S-50 amplifier for 2000 rubles was bought.
I bring here a photo of a fully finished amplifier:
As already mentioned earlier and as can be seen in the photo, an amplifier of the S-50 model of an unknown Japanese company is taken by 900 MHz (the so-called Personal Radio range - a la 27 MHz in a Japanese version with 5 watt radio stations and 5-digit personal call code). The S-50 amplifier had a 3-cascade power amplifier 5 -\u003e 50W on 3rd powerful transistors, as well as an amplifier of admission to 1 transistor, which experienced people identified as MGF-1301.
Here is a photo of a 3-cascade mind on 3 transistors, which stood there earlier:
This cost of a 3-cascade power amplifier is 900 MHz, I neatly took out of the body, and the receiving amplifier rebuilt from 900 to 1200 MHz by an inlet of the input condenser. In principle, the reception amplifier is the thing is quite unpiring in the case of installing it directly from the transceiver. Now, if on the roof, closer to the antenna ... but once there is - let it be, at least to compensate for losses in the connecting cables and the relyushki amplifier.
By the way, the OMRON GY-154P relay installed in the switch-receiving part S-50, although it is possible to work at 900 MHz frequencies maximum, possess at a frequency of 1295 MHz acceptable from my point of view. Specifications: The measured KSV turned out 1.6. It is possible that the Omron G6y or G6Z relay would be suitable here, with operating frequencies up to 2-2.5 GHz, but I was just lazy to overpass. Perhaps in the future I will try. My relay G6Z I have, 2 pieces.
For the basic scheme of the 1200 MHz amplifier, the 7L1WQG construction amplifier was taken on two RA18H1213G modules, see Appendices 1 and 2.
The printed fee of the amplifier of 1200 MHz was purchased at the Japanese auction for 2000 rubles. She is selling there now, see Appendix 7. You can, of course, it was to try to make it myself, but it seemed to me that somehow it would be difficult to make a double-sided fee with metallization of passing holes at home.
The RA18H1213G-101 modules themselves in the amount of 2 pieces were purchased in the company Sycamore, from working with which pleasant impressions remained. The modules came out in the end of 2050 rubles. Piece along with postal expenses. Here I want to highlight the question, how are the RA18H1213G modules "simply" differ from RA18H1213G-101? This question was not a unambiguous answer at the time of the manufacture of this amplifier. The RA18H1213G modules "simply" were significantly more expensive than RA18H1213G-101. The sellers themselves are usually unclear what it type to distinguish new and old batch of goods. The experimental way is found that the RA18H1213G-101 modules overlook the operating mode at a voltage on the shutters of transistors about 4-4.2 volts, and RA18H1213G "simply" - with 5 volts, judging by the information from the Internet. This also says the layout pCB 7L1WQG amplifier. I myself am the RA18H1213G modules "just" did not suck, so if I'm wrong - correct me.
If you serve the RA18H1213G-101 module on the 5 volt shutters, then it will switch to Super A mode - the rest of each module will be about 7-8 amps!
In general, we consider the basic costs of this amplifier: 2000r. (For S-50) + 2000r. (For a printed circuit board) + 4100r. (For 2 modules RA18H1213G) \u003d 8100 rubles. In my opinion, acceptable :)
In fairness, you need to add a fan with a beautiful lattice (300 r.) And a 1.5 meter power cord (90 rubles), but this is, in principle, little things.
I want to say about the cord of the power cord - initially this cord was standing with a cross section of 2.5 square meters. Mm., That was clearly not enough: at a length of 2 m. 1.4 Volt fell at a current of 20 a. It's as much as 10%! I found it unacceptable and changed by 1.5 meters with a cross section of 4 square meters. mm. Now on loss of 0.6 volts at a current of 20 a. You can simply not pay attention :)
As I have already written above, the RA18H1213G-101 modules are sharpened to the offset voltage of 4-4.2 volts, and the 7L1WQG printed circuit board design is under the RA18H1213G modules that operate when 5 volts are operating. Voltage 5 volts is taken there from the integral voltage stabilizers by 5 volts originally installed on the board. In order to reduce the voltage from 5 to 4 volts, I had to establish ordinary strong resistors 500 ohms (clearly seen on the 7th photo). The design of the printed circuit board with ease let it do. But even a fortune of rest in a couple of ampere is high for a field day, and at home this "stove" is also not needed. Therefore, voltage 12-13 volts on 5-volt stabilizers are given at the time of transmission through the transistor key to P-N-P transistor 2SB1367 (penultimate photo).
The fan rotation speed of the fan speed made the power regulator that occurred in the amplifier consisting of a variable resistor on the front panel and compound transistor 2SD1590 (Last photo). From my point of view, it is much more convenient to have smooth adjustment fan revolutionsThan to include it only at the time of the transmission, as is done in most transceivers or do it constantly.
3 Available in the LED amplifier used to indicate the power amplifier (green), receiving amplifier (yellow) and transition to transition (red).
A few words about 7L1WQG design. On the 9th photo, the photo is visible to a multiple picofradew for accurate adjustment of the input of each module.
On the 8th, the photo is visible to 1 PF condenser, connected to the output of the amplifier. Need to obtain maximum power at a given frequency. Recommended Capacity - 0.5 ... 2 PF.
Well, in conclusion, I boil you a little for your use, my dear readers :)
Imagine that you collected such an amplifier and got a power of about 60 watts per 1.2 GHz. Wonderful!
Imagine now that you are using an antenna of the Yaga type with an average for a frequency of 1200 MHz to-volume 18 dBi (this is somewhere 60 times in power).
Imagine that losses in a short piece of good cable from the amplifier to antenna are equal to 0.
And now I estimate the effective radiated power: 60 watts * 60 times \u003d 3600 watts. 3.6 kilowatta! It is more than the microwave!
For the severity of sensations, I have a little change conditions: let the amplifier have inside inside 2, and 4 Ra18H1213G modules, it is 120 watts at the output. And let the antenna, we have a stack of 4 * 48 elements. 26 Decybell gain! This is 1500 times in power. 120 * 1500 \u003d 180 kilowatt! The figure is just monstrous!
Therefore, never stand in the direction of radiation antennas of microwave ranges! And categorically avoid sending microwave emissions to your eyes - you can go blind!
Current consumption - 46 mA. Voltage in the displacement circuit V BJAS determines the level of output power (transmission coefficient) amplifier
Fig.33.11. Internal structure and Cocoovka chip TSH690, TSH691
Fig. 33.12. Typical inclusion Chip TSH690, TSH691 as an amplifier in frequency band 300-7000 MHz
and can be adjusted in the range of 0-5.5 (6.0) V. The transmission coefficient of the TSH690 chip (TSH691) at the bias voltage V Bias \u003d 2.7 V and the load resistance of 50 ohms in the frequency band up to 450 MHz is 23 (43) dB, up to 900 (950) MHz - 17 (23) dB.
The practical inclusion of the TSH690 chip, TSH691 is shown in Fig. 33.12. Recommended nominal elements: C1 \u003d C5 \u003d 100-1000 PF; C2 \u003d C4 \u003d 1000 PF; C3 \u003d 0.01 μF; L1 150 NGN; L2 56 NGN for frequencies is not over 450 MHz and 10 NGN for frequencies up to 900 MHz. The R1 resistor can adjust the output power level (can be used for an automatic output power adjustment system).
Broadband INA50311 (Fig. 33.13), manufactured by Hewlett Packard, is intended for use in mobile equipment, as well as in household radio electronic equipment, for example, as an antenna amplifier or radio frequency amplifier. The working range of the amplifier is 50-2500 MHz. The supply voltage is 5 V with a current consumed to 17 mA. Averaged amplification coefficient
Fig. 33.13. Internal structure of chip ινα50311
10 dB. The maximum power of the signal summarizes to the input at a frequency of 900 MHz, not more than 10 MW. Noise coefficient 3.4 dB.
Typical inclusion of the chip ινα50311 when powering from a voltage stabilizer 78LO05 is shown in Fig. 33.14.
Fig. 33.14. Broadband amplifier on the INA50311 chip
Shustov M. A., scheme engineering. 500 devices on analog chips. - SPb.: Science and Technology, 2013. -352 p.
In this article, I will describe the methodology of choice, alterations and settings for industrial designs of products with which I have repeatedly worked. Of all the criteria, the most fully described will be taken, and the main thing is easy to repeat the option.Chapter 1. Method for selecting an amplifier type.
There are two ways to solve this task. The first way is a fully homemade finished design. The second way is when the amplifier is based on an industrial sample of the most responsible construction site, and further work is independently conducted. Let us dwell on this option. The main part in the original design, with an output power up to 1 kW, is a resonator as the most complex and responsible node.
Consider the advantages of an industrial design.
- Professionally sharpened on turning and milling equipment with great accuracy.
- A large mass due to the thick walls of the resonator, which improves the mechanical, temporal and frequency stability of the parameters.
- High Quality.
- Heterogeneity and scattering of the field into the surrounding space are minimized.
- Professionally and accurately performed nodes for configuration and connection with the antenna.
- As a consequence of the foregoing - this weight and the ability to quickly and easily transport.
- It is difficult to purchase, every day there are less and less.
Case S. transistor amplifiers I will not consider because Even according to preliminary estimates, this is three - four times more expensive, and the "whims" of the module are large. Strict requirements for power supply at low voltages and high currents. Protection must be high-speed, and if possible from everything that can be provided. When the output power is added (not bad and when the inlet power is divided), it is desirable to use the circulator to each module. Bridges are also needed with ballast loads, to absorb the reflected signal, then you can also talk about the reliability of the amplifier. In my opinion, today, it is also easier to solve the task on the lamp.
After having studied the range of various blocks and converts a sufficient number of copies, it turns out that the choice is extremely small. The best sample is the power amplifier from the TRS R-410M (M1). For this purpose, it is impossible to suit the 310b 310BM1 block. The similar parameters have the blocks of power amplifiers from aviation radio stations P-824, P-831M (P-831 is not suitable at all), R-834 (m), P-844m, spruct-1. The experience of restructuring shows that it is much easier to reduce the frequency of resonance than to increase it, as required by the above aviation radio stations. In them, the design is such that this is a big problem. In then these radio stations are already allowed to reduce the output power on the RF edge of the range (389.975 MHz). The design of the resonator, although it is easier, but still has a separation capacity in the anode, and this is not the best decision. RF choke in the anode will also add its own capacity. In addition, the anode is still incorrecting inductance (in p-831m), intended for aligning the loading characteristics of the lamp, and this is another additional container in the resonator. With such a set of tanks, it is no longer possible to rebuild the resonator for 432 MHz, despite the fact that all the unnecessary FNHs are disabled. Designers with great difficulty pulled 390 MHz. So aviation radio stations is not the best solution for the task for 432 MHz.
Let's go back to the P-410M (M1). Developed in Mnirti, it was produced at the Vladimir factory, an electrical appliance for almost 30 years, until 1989, 11 series of radio stations (changes and modifications) were issued.
Rack 300BM1 is a power amplifier stand. In the output stage of the rack are 2 blocks of amplifiers 310b on the left and 2 block 310b on the right. They are swinging along one block 310b, in turn these blocks are swinging with blocks 320b. The rack works for two parabolas with horizontal and vertical polarization each. Used the principle of dual and quiet reception and transmission. In the World Cup mode, the block 310b gives 650 W (each) long, it is determined by the protection installed at the factory (block 330 - power of the anode and its protection), with a current of the anode 0.4-0.5 A (this mode is recommended by the manufacturer like the mode Durability of the lamp, according to reference data). Adjustment operational, potentiometer, to maximum anode current not more than 0.9 A (anode voltage + 2500 V.). This is a regular power supply.
So, the block 310b is assembled on the GS-35B lamp according to the scheme with a common grid. Anode voltage +2500 V, anode current 0.7 A, output power about 1 kW. The resonator is smoothly rebuilt in two bands.
- 476 - 525 MHz. (Channels from 1 to 50)
- 576 - 625 MHz. (Channels from 51 to 100)
R1I R2 resistors in the cathode circuit create a displacement on the lamp grid, but the initial current of the anode is not big, because Used the World Cup mode. At the output power close to 1 kW, to increase kp.d. and reducing the routine (with an old lamp) may require an increase in the initial anode current, reducing the value of R1 and R2 to 100-120 ohms each. But best of all resistors in the cathode are replaced by a T-815A stabilion chain easily to choose the desired initial current of the anode, and to protect the lamp during reception (such schemes in amplifiers a huge amount). The R6 resistor is included in the cathode chain contacts of the relay P1, when you are filled with 27 V. Tubller "Work" - "hard" in the trigger position, while the lamp is locked. The toggle switch is located in block 320 and at the same time from the block 330 (the anode power), only half of the anode voltage from the midpoint of the anode transformer (+1250 V.) is supplied to the lamp anode. Thus, one semi-complex at the same time can be used to train the lamps, which is often done. Resistor R4 shunt when measuring the anode current, and R3 when measuring the current mesh. Anode power supply (block 330) has a current protection in the range of 0.4-0.9 A. with operational adjustment.
The resonators of the 310B block have the following construction. Both resonators are directed in one direction, to the cathode - it best option Layouts (in contrast to aviation radio stations, where the anode resonator is directed to the other direction).
Anodic-grid resonator (anode) has a length of about a quarter of the wavelength. The cathode-grid resonator (cathode) has a length of about three quarters of the wavelength. Only with this combination of lengths of the resonators can be introduced chains feedback (OOS), raising the stability of the amplifier, in both lengths in a quarter of the wavelength cannot be done, such amplifiers are prone to self-excitation. Load amplifier 75 ohms. For a load of 50 ohms, it is necessary between the amplifier and the cable of 50 ohm to include a half-wave segment of a cable of 75 ohms, because A half-wave segment of the cable "transmits" the load of 50 ohms from one end of the cable to another. The amplifier and coordination will be as required.
The advantages of the unilateral design of the resonators:
- It does not need a stable, high-voltage, separating microwave capacitor with a good TKE in the anode lamp. It makes losses and impairs the characteristics of the resonator.
- Not needed anode chokewhich adds its own container to the resonator, which is also bad.
- The massive radiator of the lamp is not under the RF potential and does not affect the adjustment of the resonator (which cannot be said about aviation radio stations, where the massive radiator has a large container in the anode and increase the frequency of the resonator is no longer possible). Looking for a RF field through the radiator is minimized, which makes it easier to blow the lamps.
- Anode is grounded over the prostitutes constructive capacity of fluoroplastic tape, and the power is supplied directly to the lamp anode.
This design allows you to most fully use the WF properties of the lamp, which makes it easier.
Chapter 2. Rearrangement of the resonator, block 310b per frequency of 432 MHz.
The remission of the block is so simple that anyone who knows how to work with his hands and will take it carefully. The method described below is very simple, it is not an exclusive, widely known to many radio amateurs and they are approved, I only systematize it in this article on the basis of my experience.
Alot the anode resonator is alterated. The frequency of setting the anode resonator must be slightly moved down frequency. To do this, it is necessary to lengthen it slightly or add a small adjustable container to the resonator. Extend the resonator is easier. The experience of alterations of many instances shows that it is enough to lengthen it by 14-18 mm. To do this, it is necessary to turn the anode plunger on the contrary and the length of the anode chamber will increase. At the same time, that the plunger would move as much as possible (in the direction of the input connector) and move into the centering washer of an anode resonator, three rods leading plunger must shorten exactly 20 mm. Doing it should be slow and gently. Expand the plunger and assemble the resonator in the reverse order. General form The block is shown in photo 1. and photo2.
2.1. Sequence of dismantor disassembly.
Squeeze the heat wires (green) and cathode (yellow) from the reference rack of the block. In photo 3. The outer part of the anode resonator is visible.
1. Anode flange 5, steel, there is a sealing stocking from the braid shielded wire (reduces the seeping of the RF field).
2. We take out anodic ring 7 (current consumption) with a separation anode C1, made of fluoroplast -4 (according to something), pos.6 and pos. 8. Carefully contact 8 - this is a ring with a thickness of 0.28 mm, typed from 14 chore (half-colt) with a thickness of 0.02 mm. If some of them broke out, which happens quite often when the lamp is removed without a puller, cut new ones.
P.S. There are two different designs of this anode part.
3. Unscrew the four screws M3 and remove the antenna probe 10 with the jack from the anode cylinder 9.
4. Rear from the anode cylinder 9 Unscrew the six screws M4X15 (from the end) and slowly pull it forward (in the direction of the C1 container).
P.S. There are two fastening options, not only from behind from the end, but also from the side of the screws M3x10.
The incision of the outer part of the anode resonator is shown in Fig. 1.
5. On the mesh resonator 11 (internal cavity of the anode resonator) two negative feedback loops (OOS) are visible, which is necessary to increase the resistance from self-excitation of the amplifier. You need to handle loop carefully see photo 4.
6. Rotating the anode setting reducer, lower the plunger 12 almost close to the OC loop. Next, a powerful screwdriver, on the gearbox, turn three screws to M4x12 and release the rods 14 from the shifter 5.
7. Unscrew the grid resonator from the cathode five m3x10 screws in the rear, at the input connector, around the perimeter.
P.S. There are two versions of this rear of the resonator.
8. Unscrew the three screws M3x10 holding a centering washer 13 anodic resonator See cris 2. and photo 5 so that it is in a free position. Outside, mark his risk to be visible as it stood before, for reverse assembly. If the puck 13 does not unscrew, then when you take out the grid resonator, you can cut the screws for the screws 16. Consider this during reverse assembly.
9. Slowly pull the grid resonator forward (aside to the lamp).
Figure 2. The incision of the grid resonator is shown.
10. So the grid cylinder is released by see Figure 2. and photo 5. It can be seen that the plunger 12 is directed by sliding contacts back (to the reducer). Next, unscrew, rotating along the axis, the rods 14 from the plunger 12. Remove the back (to the side to the gearbox) puck 13, then the plunger 12. So the node is disassembled by see. Foto 6.
11. All that disassembled flushing (except the cathode resonator from the inside). Take different brushes Flotz and soap with water all rinse. Resonators must glisten. Where they are marked on the housing, the scalpels neatly scalpel, score them and deep scratches too. Next, but not much, very soft and better than a good imported eraser, polish them and oxides too. Many not try, a little bit. This is necessary that the plunger does not add new scratches when setting up.
12. The cathode resonator is 15 cm. Foto 7. You can be cleaned with a cotton swab in alcohol using a thin long screwdriver. Inside there is a worm to move its plunger.
In Fig. 3. The incision of the cathode resonator is shown. Its length is about three quarters of the wavelength, and to reduce its size, it was turned in half. For the convenience of restructuring, both halves are placed coaxially. One inside another, it is easier to move the plunger. Only the inner part of the resonator is rebuilt, the external is not rebuilt. The lamp is connected via C2 capacitor to their common point, i.e, almost by the middle of the three-hard limit, and the input connector has a complete inclusion in the line (resonator). If the worm works hard, then moving it to the lamp to the lamp, you can drop some oil and drive it along the entire length. It is necessary to do this carefully without damaging fluoroplastic tape (C2 condenser). Be sure to check the closure tester (some resistance) of the cathode on the body, it should not be.
Rooting the rod 14 for a length of 20 mm. (You can slightly more, but synchronously all three) in any way convenient for you. It is necessary to take into account that they are made of the tool steel of the brand 40x and the outside are hardened (cemented). The depth of quenching is about 0.4 mm. Personally, I make a trimming with a narrow side on a turning machine with a carbide cutter, then we sharpen to a diameter of 4 mm. And cutting the thread with a raid, pursing it from behind. Three rods leave about 40-60 minutes, if it does not rush to work.
The assembly of the resonator is made in the reverse order.
2.2. The sequence of reverse assembly of the resonator.
Chapter 3. Final amplifier assembly.
When the amplifier is finalized, it is necessary to determine how it will be used. It can be used with a separate feeder for transmission, and you can with one common feeder, according to the classic scheme. And in that, and in another case, there are pluses and its cons. Each radio amateur itself decides for himself how to do it.
Consider the first case with a separate feeder. If the feeder is 75 ohms, then no questions arise here, we use direct inclusion. If the feeder is 50 ohms, then between the amplifier and the rear (front) panel with the antenna connectors, it is necessary to seck the segments of the 75 Ohm cable, the length of the half-wave in the cable at a frequency of 432 MHz. (as well as a multiple half wave - a wave, one and a half waves, etc.), but not a quarter of the wave. From the side of the amplifier, the cable is searched for standard 75 Ohm connectors, and on the rear panel to the connectors you need.
For cable with solid polyethylene insulation, segments length are equal:
228 mm. - High calm, 456 mm. - Wave, 684 mm. - one and a half waves, etc.
For cable with solid fluoroplastic insulation, segments length are equal:
241 mm. - High calm, 482 mm. - Wave, 723 mm. - one and a half waves, etc.
The attacked connectors are included in the length of the cable segment.
The second case with one feeder. If the feeder is 75 ohms, then the REV-15 relay is used with a classic switching scheme. If the feeder is 50 ohms, then you need to apply the same segments of cables, as in the case of one feeder. Next, the Rave-15 relay, and again the same segments of the cable from the relay to the rear panel. Between the relay the same 75 ohm segment of the cable. This option with the RVV-15 relay is much cheaper than with a 50 Ohm cable and RELA-14 relay. At the same time, the coordination in both versions do not differ from each other anything. But in Moscow on the Mitinsky Radiorenka, the Rav-15 relay is much and you can buy by 200rub, and the Rave-14 relay still needs to look good and cheaper than 1500 rubles. Find difficult.
Cooling the amplifier is performed as follows. From behind to the anode flange, it is necessary to attach a turbine that works on the wallpaper from the lamp, with a capacity of at least 150-200 cubic meters / hour, is better than 250-280 cubic meters / hour. And it is very good, if you still blow the air a small turbine into the cathode pipe. The air will be held through the cathode resonator and will come out out of the grid resonator (cylinder on the sides). It is better to install it right inside the resonator, throwing a flexible air duct. The transition between the cathode nozzle and the turbine exit is better to make gestimation to exclude inside the vortex flows that hinder the movement of air.
In this article, I briefly summarized my experience and my vision of the task in such amplifiers, but everyone has the right to make a decision at its discretion.
I wish you success.
Alexander. RV3as. E-mail: This e-mail address is protected from spam bots. To see it, you need to be enabled Java-script
The more I know the modern element base, the more I am surprised at how just now electronic deviceswhich previously could only dream. For instance, antenna amplifierwhich will be discussed, has a working frequency range from 50 MHz to 4000 MHz. Yes, almost 4 GHz! In the time of my youth, it was easy to dream, and now even a novice amplifier can collect such an amplifier on one tiny chip. Moreover, not having experience with over high-frequency scheme engineering.
The antenna amplifier presented below is extremely easy to manufacture. It has a good gain, low noise and low consumption current. Plus a very wide range of work. Yes, there is also a miniature size, thanks to which it can be embedded anywhere.
Where can I apply a universal antenna amplifier?
Yes almost anywhere in wide range 50 MHz - 4000 MHz.- - As a signal amplifier television antenna For receiving both digital and analog channels.
- - As an antenna amplifier for the FM receiver.
- - Dr.
Characteristics of antenna amplifier
- Operating range: 50 MHz - 4000 MHz.
- Strengthening: 22.8 dB - 144 MHz, 20.5 dB - 432 MHz, 12.1 dB - 1296 MHz.
- Noise coefficient: 0.6 dB - 144 MHz, 0.65 dB - 432 MHz, 0.8 dB - 1296 MHz.
- Current consumption of about 25 mA.
The low-noise amplifier has proven itself perfectly. Low consumption current justifies itself.
Also the chip perfectly withstands high-frequency overload without loss of characteristics.
Production of antenna amplifier
Scheme
The scheme uses the RFMD SPF5043Z microcircuit, which can be bought on -.In fact, the whole scheme is a chip amplifier and a filter for its power.
Board amplifier
The fee can be made of foil textolite, even without etching, as I did.
We take two sided foil textolite and drink a rectangle for about 15x20 mm.
Then, a permanent marker draw a layout on the line.
And then you want to poke, and you want to cut the tracks mechanically.
Next, we all brings a soldering iron and solder SMD elements of the size 0603. The bottom side of the foil fee closer to the general wire, thereby shielding the substrate.
Setting and testing
The tincture is not required, you can of course measure the input voltage, which must be within 3.3 V and the current consumed is approximately 25 mA. Also, if you work in the range above 1 GHz, it may be necessary to coordinate the input circuit, a reduction in the capacitor to 9 PF.Connect the board to the antenna. Check showed good strengthening and low noise.
It will be very good if you place a fee in the shielded case, such as this.
You can buy a fee of the ready-made amplifier on, but it is also more expensive than the chip separately. So it is better to freeze as it seems to me.
Supplement schema
For the power of the circuit, voltage is required 3.3 V. This is not entirely convenient, for example, if you use the amplifier in the car with a voltage on-board network 12 V.
For these purposes, you can enter the stabilizer in the scheme.
Connecting the amplifier to the antenna
By location, the amplifier should be placed in the immediate vicinity of the antenna.To protect against statics and thunderstorms, it is desirable that the antenna would be closed by dCThat is, you need to use a loop or frame vibrator. Antenna of type "" will be an excellent option.