Adjustments in radio-electronic equipment. Technical design of the fuel equipment repair area

Remote control of moving models is based on interaction between a person and a model. The pilot sees the position of the model in space and its speed. Using remote control equipment, he gives commands to the model’s actuators, which turn the rudders or control the engines, thereby the pilot changes the position and direction of the model’s movement in accordance with his desire. The transmission of commands from the pilot to the model occurs mostly via radio. An exception can be found only for indoor models, where, along with radio, infrared radiation is used, and ultrasound is also very rarely used to control underwater vehicles.

The radio control equipment consists of a transmitter, which is located by the pilot, and a receiver and actuators located on the model. This article will help you gain an understanding of how a transmitter works and which transmitter you need.

Design types of transmitters

Based on the design of the controls, which are actually acted upon by the pilot’s fingers, transmitters are divided into joystick and pistol type. The first ones usually have two two-axis joysticks. Such transmitters are used to control flying models. In joystick transmitters, the handle has built-in springs that return it to the neutral position when released. As a rule, one of the directions of some kind of joystick is used to control the traction motor - it does not have a return spring. In this case, the handle is pressed with a ratchet (for airplanes) or a smooth braking plate (for helicopters). Using such transmitters, you can also successfully control floating and driving models, but special pistol-type transmitters have been invented for them. Here the steering wheel controls the direction of movement of the model, and the trigger controls its engine and brakes.

In recent years, transmitters with a single two-axis joystick have appeared. They belong to the category of cheap devices and can be used to control both simplified flying and ground equipment. They can be used productively only at the most basic level. Transmitters with two single-axis joysticks have a similar purpose:

To finish with design variations, let’s add a division of joystick transmitters into monoblock and modular. If the first ones are fully equipped with all components and are immediately ready for use, then the modular ones represent a basis into which the pilot, at his discretion, adds the additional controls he needs:

There are two ways to hold the transmitter. Remote control transmitters are hung around the pilot's neck using a special belt or stand. The pilot's hands rest on the transmitter body, and each joystick is controlled by two fingers - the index and thumb. This is the so-called European school. The pilot holds the handheld transmitter in his hands, and each joystick is controlled by one thumb. This manner is attributed to the American school.

The handheld transmitter can also be held in your hands and controlled in a European way. You can also use it in a remote control version if you buy a special table-stand for it. You can make a table no worse than a branded one yourself. Such tables are also required for some remote control transmitters. Which manner is more common among us depends on the age of the pilot. Young people, according to our observations, are more inclined to American customs, and the older generation is more inclined to the conservatism of Europe.

Number of channels and control knob layout

Controlling moving models requires influencing several functions simultaneously. Therefore, radio control transmitters are made multi-channel. Let's consider the number and purpose of channels.

For cars and ship models, two channels are needed: control of the direction of movement and engine speed. Sophisticated pistol transmitters also have a third channel, which can be used to control the mixture formation of the internal combustion engine (radio needle).

To control the simplest flying models, two channels can also be used: elevators and ailerons for gliders and airplanes, or elevators and rudder. For hang gliders, roll control and motor power are used. This scheme is also used on some simple gliders - rudder and engine switching on. Such two-channel transmitters can be used for fleet models and entry-level electric aircraft. However, to fully control an airplane you need at least four, and a helicopter - five channels. For aircraft, two two-axis joysticks provide control functions for the elevator, direction, ailerons and engine throttle. The specific layout of functions for joysticks is of two types: Mode 1 - elevator on the left vertically and rudder horizontally, gas on the right vertically and roll horizontally; Mode 2 - gas on the left vertically and rudder horizontally, elevator on the right vertically and roll horizontally. There are also Mode 3 and 4, but they are not very common.

Mode 1 is also called the two-handed version, and Mode 2 is called the one-handed version. These names follow from the fact that in the latter version you can control the plane for quite a long time with one hand, holding a can of beer in the other. Modellers' debate about the advantages of one scheme or another has not subsided for many years. For the authors, these disputes are reminiscent of the debate about the advantages of blondes over brunettes. In any case, most transmitters can easily be switched from one layout to another.

To effectively control a helicopter, you already need five channels (not counting the channel for controlling the sensitivity of the gyroscope). Here there is a combination of two functions per direction of the joystick (we will look at how this happens later). The handle layouts are in many ways similar to airplane ones. Among the features is the throttle stick, which some pilots invert (minimum throttle is at the top, maximum throttle is at the bottom), as they find it more convenient.

Above, we considered the minimum required number of channels to control the movement of models. But there can be a lot of functions for managing models. Especially on replica models. On airplanes, this can be control of landing gear retraction, flaps and other wing mechanization, side lights, and landing gear wheel brakes. Model copies of ships that imitate various mechanisms of real ships have even more functions. Gliders use control of flaperons and air brakes (interceptors), retractable landing gear and other functions. Helicopters also use control of gyroscope sensitivity, retractable landing gear and other additional functions. To control all these functions, transmitters are available with a number of channels of 6, 7, 8 and up to 12. In addition, modular transmitters have the ability to increase the number of channels.

It should be noted here that control channels are of two types - proportional and discrete. The easiest way to explain this is in a car: gas is a proportional channel, and headlights are discrete. Currently, discrete channels are used only to control auxiliary functions: turning on the headlights, releasing the landing gear. All main control functions are carried out through proportional channels. In this case, the amount of steering wheel deflection on the model is proportional to the amount of joystick deflection on the transmitter. So, in modular transmitters it is possible to expand the number of both proportional and discrete channels. We will look at how this is done technically later.

There is one fundamental ergonomic problem associated with multichannel. A person has only two hands, which can control only four functions at a time. On real airplanes, pilots' feet (pedals) are also used. Modelers haven't come to this point yet. Therefore, the remaining channels are controlled from individual toggle switches for discrete channels or knobs for proportional ones, or these auxiliary functions are obtained by calculation from the main ones. In addition, the model control signals may also not be directly controlled from the joysticks, but undergo pre-processing.

Control signal processing and mixing

After reading the previous chapters, we hope you were able to understand two main points:

• The transmitter can be held in different ways, but the main thing is not to drop it
• There are many channels in transmitters, but you always need to control them with only two hands, which is sometimes not very easy

Now that we have a preliminary understanding, let's look at a few more practical points that transmitters implement:

• trimming
• adjusting the sensitivity of the knobs
• channel reverse
• limitation of steering gear costs
• mixing
• other functions

Trimming is a very important thing. If you release the transmitter handles while driving the model, the springs will return them to the neutral position. It is quite logical to expect that the model will move straight. However, in practice this is not always the case. There are many reasons for this. For example, if you are launching a newly built aircraft, then you may incorrectly take into account the torque from the engine, and in general the model is rarely perfectly symmetrical and correct in shape. As a result, even if the rudders appear to be level, the model will still not fly straight, but in some other way. To correct the situation, the position of the steering wheels will need to be adjusted. But it is quite clear that doing this directly on the model during launches is very impractical. It would be much easier to slightly move the transmitter handles in the desired directions. This is exactly why trimmers were invented! These are small additional levers on the sides of the joysticks that set their displacement. Now, if you need to adjust the neutral position of the rudders on the model, you just need to use the desired trimmer. Moreover, what is especially valuable is that trimming can be carried out right on the go, during launches, observing the reaction of the model. If you find that initially the model does not need trimming, consider yourself very lucky.

Adjusting the sensitivity of the knob is a completely understandable function. When you set up controls for a specific model, you need to set the sensitivity so that the controls are most comfortable for you. Otherwise, the model will respond to the transmitter knobs too sharply or, on the contrary, too sluggishly. More “advanced” models allow you to set an exponential sensitivity function for the transmitter knobs in order to more accurately “steer” with slight deviations.

If we now think back to the model, we will find that depending on how the steering gears are installed and how the linkages are connected, we may need to change their direction of operation. To achieve this, all transmitters allow independent reversal of control channels.

The mechanics of the model itself may have limitations, so sometimes it is necessary to limit the stroke of the steering gears. To achieve this, many transmitters have a separate travel limitation function, although if it is missing, you can try to get by by adjusting the sensitivity of the knobs.

Now it's time to touch on more complex aspects and tell you what mixing is.

Sometimes it may be necessary for the steering wheel on a model to be controlled simultaneously from several transmitter handles. A good example is a flying wing, where both ailerons control the height and roll of the model, i.e. the movement of each depends on the movement of the altitude stick and roll stick on the transmitter. Such ailerons are called elevons:

When we control the height, both elevons deflect simultaneously up or down, and when we control the roll, the elevons work in antiphase.

The elevon signals are calculated as a half-sum and half-difference of the altitude and roll signals:

Elevon1 = (height + roll) / 2
Elevon2 = (height - roll) / 2

Those. The signals from the two control channels are mixed and then transmitted to the two execution channels. Such calculations, which involve input from multiple control knobs, are called mixing.

Mixing can be implemented both in the transmitter and on the model. And the implementation itself can be either electronic or mechanical.

Especially for beginners (with the exception of helicopter pilots), I would like to note that the models you will start with will most likely not require mixers for their operation. Moreover, you may not need mixers for very long (or maybe you will never need them at all). So if you decide to buy yourself a simple 4-channel joystick equipment, or 2-channel pistol equipment, then you shouldn’t be upset about the missing mixers.

You'll find a ton of other features in good transmitters in the upper price range. The extent to which they are needed for a particular model is a debatable issue. To get an idea about them, you can read the descriptions of such transmitters on the manufacturers’ websites.

Analog and computer transmitters

To understand the difference between analog and computer transmitters, let's look at a more realistic example. About fifteen years ago, programmable phones began to spread. They differed from the usual ones in that, in addition to conversation and identifying the number of the calling subscriber, they made it possible to program one button to dial an entire number, or create a “black list” of subscribers to whose calls the phone did not respond. A bunch of additional services appeared that the average subscriber often did not need. So, an analog transmitter is like a simple telephone. It usually has no more than 6 channels. As a rule, the simplest of the services described above are implemented: there is channel reversal (sometimes not all), trimming and sensitivity adjustment (usually for the first 4 channels), setting the extreme values ​​of the gas channel (idle speed and maximum speed). Adjustments are made using switches and potentiometers, sometimes using a small screwdriver. Such devices are easy to learn, but their operational flexibility is limited.

Computer equipment is characterized by the fact that all settings can be programmed using buttons and a display in the same way as on programmable phones. There can be a lot of services here. The main ones worth noting are the following:

1. Availability of memory for several models. A very convenient thing. You can remember all the settings for mixers, reverses and rates, so you don’t have to rebuild the transmitter when you decide to use it with another model.
2. Memorizing trim values. A very convenient feature. You don't have to worry that the trimmers will accidentally get knocked down during transportation and you'll have to remember their position. Before starting the model, it will be enough to just check that the trimmers are installed “in the center”.
3. A large number of built-in mixers and operating mode switches will allow you to implement a wide variety of functions on complex models.
4. The presence of a display makes it much easier to configure the equipment.

The number of functions and price of computer equipment varies quite widely. It’s best to always look at the manufacturer’s website or instructions for specific features.

The cheapest devices may come with a minimum of functions and are focused primarily on ease of use. These are primarily model memory, digital trimmers and a couple of mixers.

More complex transmitters, as a rule, differ in the number of functions, an expanded display and additional data encoding modes (to protect against interference and increase the speed of information transfer).

Top models of computer transmitters have large-area graphic displays, in some cases even with touch controls:

It makes sense to buy such models for ease of use or for some particularly tricky functions (which may only be needed if you want to seriously engage in sports). Sophistication leads to the fact that top models already compete with each other not in the number of functions, but in ease of programming.

Many computer transmitters have replaceable model settings memory modules that allow you to expand the built-in memory and also easily transfer model settings from one transmitter to another. A number of models provide for changing the control program by replacing a special board inside the transmitter. In this case, you can change not only the language of menu prompts (the authors have not encountered Russian, by the way), but also install more recent software with new capabilities into the transmitter.

It should be noted that flexibility in the use of computer equipment also has negative features. One of the authors recently gave his mother-in-law a programmable phone, so she tinkered with programming it for a week and returned it with a request to buy her a simple, as she says, “normal phone.”

Principles of radio signal generation

Now we will move away from the problems of modeling and consider issues of radio engineering, namely, how information from the transmitter gets to the receiver. For those who do not really understand what a radio signal is, you can skip this chapter, paying attention only to the important recommendations given at the end.

So, the basics of model radio engineering. In order for the radio signal emitted by the transmitter to carry useful information, it undergoes modulation. That is, the control signal changes the parameters of the radio frequency carrier. In practice, control of the amplitude and frequency of the carrier, denoted by the letters AM (Amplitude Modulation) and FM (Frequency Modulation), has been used. Radio control uses only discrete two-level modulation. In the AM version, the carrier has either a maximum or zero level. In the FM version, a signal of constant amplitude is emitted, either with a frequency F, or with a slightly shifted frequency F + df. The FM transmitter signal resembles the sum of two signals from two AM transmitters operating in antiphase at frequencies F and F +df, respectively. From this it can be understood, even without delving into the intricacies of radio signal processing in the receiver, that under the same interference conditions, an FM signal has fundamentally greater noise immunity than an AM signal. AM equipment is usually cheaper, but the difference is not very large. Currently, the use of AM equipment is justified only in cases where the distance to the model is relatively small. As a rule, this is true for car models, ship models and indoor aircraft models. In general, you can fly using AM equipment only with great caution and away from industrial centers. Accidents are too expensive.

Modulation, as we have established, allows useful information to be superimposed on the emitted carrier. However, radio control uses only multi-channel information transmission. To do this, all channels are compressed into one through coding. Currently, only pulse-width modulation, denoted by the letters PPM (Pulse Phase Modulation) and pulse-code modulation, denoted by the letters PCM (Pulse Code Modulation), are used for this. Due to the fact that the word "modulation" is used to refer to coding in multi-channel radio control and to superimpose information on the carrier, these concepts are often confused. Now it should become clear to you that these are “two big differences,” as they like to say in Odessa.

Let's consider a typical PPM signal of five-channel equipment:

The PPM signal has a fixed period length T=20ms. This means that information about the positions of the control knobs on the transmitter reaches the model 50 times per second, which determines the speed of the control equipment. As a rule, this is enough, since the pilot’s reaction speed to the model’s behavior is much slower. All channels are numbered and transmitted in numerical order. The value of the signal in the channel is determined by the time interval between the first and second pulse - for the first channel, between the second and third - for the second channel, etc.

The range of changes in the time interval when moving the joystick from one extreme position to another is defined from 1 to 2 ms. A value of 1.5 ms corresponds to the middle (neutral) position of the joystick (control stick). The duration of the interchannel pulse is about 0.3 ms. This PPM signal structure is standard for all manufacturers of RC equipment. The average handle position values ​​may differ slightly from one manufacturer to another: 1.52 ms for Futaba, 1.5 ms for Hitec and 1.6 for Multiplex. The range of variation for some types of computer transmitters can be wider, reaching from 0.8 ms to 2.2 ms. However, such variations allow the mixed use of hardware components from different manufacturers operating in PPM encoding mode.

As an alternative to PPM coding, PCM coding was developed about 15 years ago. Unfortunately, various manufacturers of RC equipment could not agree on a single format for the PCM signal, and each manufacturer came up with their own. More details about the specific formats of PCM signals from equipment from different companies are described in the article “PPM or PCM?”. The advantages and disadvantages of PCM coding are also given there. Here we will only mention a consequence of the different formats: in PCM mode, only receivers and transmitters from the same manufacturer can be used together.

A few words about the designations of modulation modes. Combinations of two types of carrier modulation and two coding methods give rise to three options for equipment modes. Three because amplitude modulation is not used together with pulse-code modulation - there is no point. The first has too poor noise immunity, which is the main purpose of using pulse-code modulation. These three combinations are often referred to as: AM, FM and PCM. It is clear that in AM there is amplitude modulation and PPM coding, in FM there is frequency modulation and PPM coding, and in PCM there is frequency modulation and PPM coding.

So now you know that:

• the use of AM equipment is justified only for car models, ship models and indoor aircraft models.
• Flying using AM equipment is only possible with great caution and away from industrial centers.
• You can use hardware components from different manufacturers operating in PPM encoding mode.
• In PCM mode, only receivers and transmitters from the same manufacturer can be used together.

Modular expansion

Modular transmitters are produced mainly in remote control versions. In this case, there is a lot of space on the remote control panel where you can place additional knobs, toggle switches and other controls. Among other cases, we will mention a module for controlling a twin-engine boat or tank. It is installed instead of a two-axis joystick and is very similar to the clutch levers of a crawler tractor. With its help you can deploy the following models on a patch:

Now we will explain how channels are compacted with a modular expansion of their number. Different manufacturers produce modules that allow up to 8 proportional or discrete additional channels to be transmitted over one main channel. In this case, an encoder module with eight knobs or toggle switches is installed in the transmitter, occupying one of the main channels, and a decoder with eight proportional or discrete outputs is connected to the receiver in the slot of this channel. The principle of compaction comes down to sequential transmission through this main channel of one additional channel in every 20 millisecond cycle. That is, information about all eight additional channels from the transmitter to the receiver will reach only after eight signal cycles - in 0.16 seconds. For each decompressed channel, the decoder produces an output signal as usual - once every 0.02 seconds, repeating the same value eight times. From this it can be seen that compacted channels have much lower speed and are inappropriate to use to control fast and important control functions of the model. In this way, you can create 30-channel equipment sets. What is this for? As an example, here is a list of functions of the lighting and signaling module of a copy of a mainline tractor:

• parking lights
• High beam
• Low beam
• Spotlight Finder
• Stop signal
• Engaging reverse gear (the last two functions are activated automatically from the throttle control position)
• Left turn
• Right turn
• Cabin lighting
• Klaxon
• Flashing Light

Modular transmitters are more often used by copyists, for whom the spectacular behavior of the model, the realism of how it looks, and not its dynamics of behavior are more important. A large number of different modules for specific purposes are produced for modular transmitters. We will only mention here the aileron trimming unit for aerobatic models. Unlike monoblock transmitters, where control parameters in the “flaperon” modes, the air brake (in our opinion “crocodile”, and in the West “butterfly”) and differential deviation are programmed in the menu, here each parameter is displayed on its own knob. This allows you to make adjustments directly in the air, i.e. without taking his eyes off the flying model. Although this is also a matter of taste.

Transmitter device

The radio control equipment transmitter consists of a housing, controls (joysticks, knobs, toggle switches, etc.), an encoder board, an RF module, an antenna and a battery. In addition, the computer transmitter has a display and programming buttons. Explanations on the body and controls were given above.

The encoder board contains the entire low-frequency circuit of the transmitter. The encoder sequentially polls the position of the controls (joysticks, knobs, toggle switches, etc.) and, in accordance with it, generates channel pulses of the PPM (or PCM) signal. All mixing and other services (exponent, stroke limitation, etc.) are also calculated here. From the encoder, the signal goes to the RF module and the trainer connector (if there is one).

The RF module contains the high-frequency part of the transmitter. It contains a master quartz oscillator that determines the channel frequency, a frequency or amplitude modulator, an amplifier-output stage of the transmitter, a matching circuit with the antenna and filtering out-of-band emissions. In simple transmitters, the RF module is assembled on a separate printed circuit board and placed inside the transmitter housing. In more advanced models, the RF module is housed in a separate housing and is inserted into a niche on the transmitter:

In this case, there is no replaceable quartz, and the radio signal carrier is formed by a special frequency synthesizer. The frequency (channel) at which the transmitter will operate is set using switches on the RF unit. Some top transmitter models can set the synthesizer frequency directly from the programming menu. Such capabilities make it possible to easily distribute pilots to different channels in any combination of races and rounds of competition.

Almost all radio control transmitters use a telescopic antenna. When unfolded it is quite effective, and when folded it is compact. In some cases, it is possible to replace the standard antenna with a shortened helical antenna, produced by many companies, or with a homemade one.

It is much more convenient to use and more durable in the hustle and bustle of competition. However, due to the laws of radio physics, its efficiency is always lower than that of a standard telescopic one, and it is not recommended for use for flying models in complex interference environments in large cities.

During use, the telescopic antenna must be extended to its full length, otherwise the communication range and reliability drop sharply. With the antenna folded, before flights (races), the reliability of the radio channel is checked - the equipment should work at a distance of up to 25-30 meters. Folding the antenna usually does not damage the operating transmitter. In practice, there have been isolated cases of the RF module failing when folding the antenna. Apparently, they were caused by low-quality components and could have happened with the same probability regardless of the folding of the antenna. And yet, the telescopic antenna of the transmitter does not radiate the signal well in the direction of its axis. Therefore, try not to point the antenna at the model. Especially if it is far away and the interference environment is bad.

Most even simple transmitters have a “trainer-student” function, which allows a novice pilot to be trained by a more experienced one. To do this, two transmitters are connected with a cable through a special “trainer” connector. The trainer's transmitter is switched on to the radio signal emission mode. The student's transmitter does not emit a radio signal, but the PPM signal from his encoder is transmitted via cable to the trainer's transmitter. The latter has a “trainer-student” switch. In the “trainer” position, a signal about the position of the trainer transmitter handles is transmitted to the model. In the "student" position - from the student transmitter. Since the switch is in the hands of the trainer, he takes over control of the model at any moment and thereby protects the beginner, preventing him from “making wood.” This is how flying model pilots are taught. The trainer connector contains the output of the encoder, the input of the trainer-student switch, ground, and the power control contacts of the encoder and the RF module. On some models, connecting the cable turns on the encoder's power while the transmitter's power is off. In others, shorting the control contact to ground turns off the RF module when the transmitter power is turned on. In addition to the main function, the trainer connector is used to connect the transmitter to a computer when used with a simulator.

The power supply for the transmitters is standardized and is supplied from a nickel-cadmium (or NiMH) battery with a nominal voltage of 9.6 volts, i.e. from eight cans. The battery compartment in different transmitters has different sizes, which means that the finished battery from one transmitter may not fit another in size.

The simplest transmitters can use ordinary disposable batteries. For regular use this is ruinous.

Top models of transmitters may have additional components useful to the modeler. Multiplex, for example, in its 4000 model integrates a panoramic scanning receiver, which allows you to see the presence of emissions in the frequency range before flights. Some transmitters have a built-in (with remote sensor) tachometer. There are options for a coaching cable made on the basis of optical fiber, which galvanically isolates the transmitters and does not create interference. There are even means of wirelessly connecting a trainer with a student. Many computer transmitters have replaceable memory modules that store information about the model settings. They allow you to expand the set of programmed models and transfer them from transmitter to transmitter.

So now you know that:

• by replacing quartz, you can change the channel of the equipment within the operating range
• By replacing the replaceable RF module, it is easy to switch from one band to another.
• RF modules are designed to work with only one type of modulation: amplitude or frequency.
• During use, the telescopic antenna must be extended to its full length, otherwise the communication range and reliability drop sharply.
• Folding the antenna does not damage the operating transmitter.

Conclusion

After reading a brief introduction to the topic of radio control equipment transmitters, you have a rough idea of ​​what kind of transmitter you need. However, the variety of market offers does not make the problem of choice easier, especially at the beginning of radio modeling. Let us give you some advice on this matter.

The radio control transmitter is the most enduring part of all things modeling. It is in the hands of the pilot, and does not rush around at terrible speed, trying to injure those around him and the model itself with all its contents. If you do not reverse the polarity of the transmitter battery, do not step on it or drop it on the floor, then it can faithfully serve for years and decades. If you are engaged in modeling not alone, but together with a close friend, you can generally purchase one transmitter for two. Since the transmitter is a durable component, it is better to purchase a good device right away. It won't be cheap, but it will cover your growing needs over time, and you won't have to sell it a year later for half the price because it's missing any mixers or other features. But you shouldn’t go to extremes and immediately buy a device in the upper price range. The transmitters for champion athletes contain capabilities that will take years to understand and use. Think about whether you need to pay extra money for prestige.

According to the authors' experience, the quality of transmitters depends on their price group. Apparently, at manufacturing plants, more expensive models are more strictly controlled both during assembly and at the stage of purchasing components. Unprovoked transmitter failure is generally an extremely rare thing, and almost never occurs in expensive models.

For expensive transmitters, special aluminum cases are produced that are used for storage and transportation to the airfield. For cheaper devices, you can purchase a special plastic box, or make it yourself. Such special packaging should not be neglected by those who regularly (weekly) go on flights or races. It will more than once save your favorite transmitter from shock and destruction, which has served you for many years and may be inherited by your son.

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Reading “The Source” will help in the future to truly understand the ideas of the novel “Atlas Shrugged,” as well as the philosophical and journalistic books of Ayn Rand.

Who is author
Ayn Rand (1905-1982) is our former compatriot who became an iconic American writer. Author of four best-selling novels and numerous articles. The creator of a philosophical concept based on the principle of free will, the primacy of rationality and the “morality of reasonable egoism.”

Key Concepts
Freedom, personal independence, morality of selfishness.

1005 rub

Lolita

In 1955, LOLITA was published - the third American novel by Vladimir Nabokov, the creator of The Luzhin Defense, Despair, Invitation to an Execution and The Gift.
Causing a scandal on both sides of the ocean, this book elevated the author to the top of the literary Olympus and became one of the most famous and, without a doubt, the greatest works of the 20th century. Today, when the polemical passions around “Lolita” have long subsided, we can confidently say that this is a book about great love that has overcome illness, death and time, love open to infinity, “love at first sight, at last sight, at the eternal glance."
In this edition, a fragment of Humbert's diary from the third chapter of the second part of the novel has been restored.

128 rub

Fried green tomatoes at Polustanok cafe

“Fried Green Tomatoes” by Fannie Flagg almost after the first edition in Russian became a cult book in Russia. Over two decades, the novel has been republished many, many times, but even today its popularity is extremely high. “Fried Green Tomatoes” is probably already the third generation of the reading public. The novel is placed on a par with the great American books - with "To Kill a Mockingbird" and "Helkebury Finn" - and the very mention of Flagg's book in this series testifies to its strength. And absolutely for sure: “Fried Green Tomatoes” is a classic of American and world literature. If you zoom into Fanny Flagg’s novel, you can probably hear someone’s laughter, crying, conversations, the noise of a train, the rustling of leaves, the clanking of forks and spoons. Listen to the sounds breaking through the cover, and you will learn the story of one small American town, in which, like everywhere else in the world, love and pain, fears and hopes, friendship and hatred are intertwined. This story will be told with such sincerity that it will be remembered for many years, and Fannie Flagg's novel will become one of the most beloved books - as it became for so many around the world. For Fanny Flagg's great novel is life itself.

424 rub

Back to you

Once upon a time, the public was shocked by the story of Charlotte, who was shipwrecked during her honeymoon and returned home only two years later. She spent a lot of time on the open sea, and then on a desert island in the company of an unsociable man named Gray, thanks to whom she was able to survive.
Many years later, Charlotte finds a message in a bottle on the shore. This is incredible, but it follows that Gray is still waiting for her on the island, and, in his opinion, only a few days have passed since their separation......

710 rub

Three and a half. With prisoner respect and brotherly warmth

In December 2014, brothers Oleg and Alexey Navalny were convicted in the Yves Rocher case. Alexey received 3 1/2 years of probation, Oleg - 3 1/2 years in prison. The European Court of Human Rights recognized the sentence as arbitrary and unreasonable, but Oleg served the entire term, 1278 days. In this book, most of which was written in the colony, he outlined everything that happened to him during this time and provided the story with detailed diagrams and illustrations. From it you can find out how the “red” zone is different. from the “black”, why sheets and towels are needed in prison, what SUS, BUR and AUE are, where to hide a SIM card during a search and why Chewbacca became a convict. But the main thing is a book about how not to get lost even in the wildest, terrible and ridiculous circumstances. QUOTE “I've told this story about four billion times everywhere I can, but if you haven't heard, here's my recipe for killing time: Step 1. Make yourself a schedule for the day. Step 2. Fill it with all sorts of activities: sports, reading, learning, creativity, etc. It is advisable that the same set of activities not be repeated every day. Step 3: Make the schedule unworkable. It turns out that all day you do something according to the plan, but no matter how hard you try, you can’t get it done. This means there is a catastrophic lack of time. That is, it is killed as efficiently as possible. Ha! Checkmate, time."

459 rub

Purpose of adjustment and operating conditions of radio-electronic equipment and devices

Adjustment of radio-electronic equipment is carried out in order to bring the parameters of products to values ​​that meet the requirements of technical specifications, GOSTs or samples accepted as the standard.

The main objectives of adjustment are compensation (adjustment) of permissible deviations in the parameters of device elements, as well as identifying installation errors and other malfunctions. Usually, for this purpose, they adjust the modes of semiconductor devices, adjust the low-frequency amplifier and detector, check the serviceability of various elements, and set the modes of individual stages and the entire device.

Adjustment is made by two methods: using measuring instruments and comparing the device being adjusted with a sample, which is called electrical copying.

The accuracy and reliability of radio equipment and instruments depend on the technological process of their production. Therefore, the technical level of manufacturing of individual elements and blocks determines the volume and degree of accuracy of radio equipment adjustment.

Before proceeding with adjustment work, the adjuster must study the device that is subject to adjustment, become familiar with the technical conditions for it, the main output and intermediate parameter values, general view drawings, electrical, kinematic and other diagrams. It is also important to know under what conditions it will be used. In addition, the adjuster must know the characteristics of adjusting and measuring equipment and measurement methods, the sequence of adjustment operations, and be able to use complex electrical measuring instruments. Typically, adjustment operations are entrusted to highly qualified workers.

The traffic controller's workplace must be equipped with the necessary equipment, instruments and devices. When using special stands for measurements, the regulator must study the purpose of each structural element of the stand and control knobs. In addition, he should familiarize himself with the safety instructions, which define measures to prevent injury, as well as ways to quickly eliminate the danger of electric shock and exposure to electromagnetic fields of ultra-high frequencies.

The workplace of a traffic controller - a repairman of radio-electronic equipment and instruments - must be equipped with the necessary tools (Fig. 6.1), which include:

The operating conditions of radio equipment and devices usually mean the external environment in which these products operate, as well as the physical influences to which they are exposed (shock, vibration).

The operation of radio equipment is most influenced by a decrease in pressure and a change in temperature, which can lead to misadjustment. Under the influence of temperature, the volume, hardness, elasticity, electrical, magnetic and optical properties of materials change. Temperature changes in combination with high humidity have a particularly strong effect on the operation of radio equipment. The content of salts in the air (sea air), sand, and dust also has a significant impact. The nature of the effect of moisture on parts and units of radio equipment can be different. This includes condensation of water vapor on the surface of products, splashes of water or rain, and short-term or long-term immersion in water.

With prolonged exposure to high and low temperatures and moisture on parts and units of radio equipment, the inductance of the coils and the capacitance of the capacitors change, the stability of the operating frequency is disrupted, the sensitivity and selectivity of radio receiving devices, as well as the power and efficiency of transmitting devices, are reduced. In addition, leaks and short circuits appear in connecting cables and electrical connectors, and the insulation of individual parts and units deteriorates. The deposition of moisture on the surface of metals creates favorable conditions for corrosion, which leads to breakage of thin wires and disruption of contacts.

Adjustment of radio-electronic equipment and instruments

Carrying out adjustment work is associated with great responsibility, since it completes the manufacture of the product. Therefore, it is important that the adjuster thinks through his actions in advance before performing any operations the need for which arises during the adjustment process. Such operations include, in particular, the replacement of individual assembly units and parts. The volume of dismantling, assembly and installation work is usually small, but ensuring high quality of their performance is an immutable law. Particular attention should be paid to dismantling work, during which the solder leads of elements that have additional mechanical fastenings are released. These operations require special attention and careful execution, otherwise peeling of printed conductors, failure of microcircuits, burning of the insulation of overhead conductors, and breakage of leads may occur.

Work related directly to product adjustment in serial and mass production conditions is determined by technical documentation - technological maps or adjustment instructions. At the stages of developing prototypes and experimental series, the adjuster must reject technical documentation for adjustment, determine the most productive methods of adjustment sequence, as well as the limits of the nominal values ​​of the elements selected, and identify defects in the design and manufacturing process.

Before starting to adjust the measuring equipment, the adjuster must carefully study the technical data of the devices, the rules of their operation and be able to use them in practice.

Before you begin connecting the regulated product to power supplies and measuring instruments, you must ensure that they are in good working order and that normal supply voltages are available. Checking the presence of normal supply voltages, and sometimes the level of their ripples, is carried out directly at the input of the power circuits of the regulated product.

One of the reasons for errors during adjustment may be the incorrect choice of cable from the kit to the measuring device. One of these cables may be open at the end, another may be loaded with a resistance of 50 or 75 ohms, a third may have a built-in detector head, and the fourth may have a built-in filter or series resistance. The wrong choice of cable inevitably leads to gross errors and sometimes to disruption of the functioning of the controlled product.

Another reason for errors may be an open circuit in the cable or connecting wires, as well as broken contacts in the connectors connecting the cables on one side to measuring instruments or power supplies, and on the other to the controlled device. There are various ways to check the serviceability of connecting devices, the simplest of which is to replace the questionable cable with a working one. Poor contact in connectors is detected by slight rocking or slight movement of the moving part of the connector.

1) tuning one or more circuits to a fixed frequency (in intermediate frequency stages, blocking filter circuits and in radio receivers with a fixed tuning);

(L1. pp. 186-191)

Adjustment of radio-electronic equipment is carried out in order to bring the parameters of products to values ​​that meet the requirements of technical specifications, GOSTs or samples accepted as the standard.

The main objectives of adjustment are to compensate for permissible deviations in the parameters of device elements, as well as to identify installation errors and other malfunctions.

Adjustment is made by two methods: using measuring instruments and comparing the device being adjusted with a sample, which is called electrical copying.

Before starting adjustment work, it is necessary to study the device that is subject to adjustment, familiarize yourself with the technical conditions for it, the main output and intermediate parameter values, general drawings and electrical diagrams. The regulator must know the conditions under which the equipment will be operated and the characteristics of the measuring equipment.

Proper organization of a traffic controller's workplace significantly affects the reduction of labor costs and improves the quality of regulatory work. For the correct organization of the technological adjustment process, appropriate control and measuring equipment and tools are required. The accuracy of the measuring equipment used must exceed approximately 3 times the specified adjustment accuracy. The equipment is adjusted using universal standard measuring and special factory instruments, which are various kinds of simulators, load equivalents, and control panels. Special devices for adjustment work, so-called non-standard devices, are aimed at minimizing the complexity of adjustment and reducing preparatory and final time. Therefore, they are manufactured specifically for each type of radio-electronic device.

A feature of the equipment of the controller’s workplace is that the complexity of standard and non-standard instrumentation often exceeds the complexity of the device being adjusted.

The controller's workplace for single and small-scale production includes a workbench, a chair, and a rack.

The workbench should be comfortable and have sufficient strength and stability to prevent it from shaking or moving during work. Workbenches should be installed at a distance that ensures natural working conditions and the absence of mutual influence of devices installed on them. When a large number of measuring instruments are located in a room, measures must be taken to remove excess heat from workplaces and ensure normal temperature.

The composition of the workplace is determined by the complexity and design features of the adjustable device. The number of control and measuring instruments at the workplace should be the minimum necessary to ensure uninterrupted operation during the shift. The equipment at the workplace must be placed in such a way that it is convenient to use the adjustment controls. Periodically used devices must be in the field of view of the traffic controller in the same place.

The lighting of the workplace must be correct and sufficient; the required illumination is determined by current sanitary standards and the nature of the work performed. With natural and artificial lighting, it is recommended to place workstations and light sources so that the light falls from the left or from the front. In the case of local lighting, the light should fall evenly, it should not dazzle the eyes, create glare on instrument scales, and not make it difficult to observe the light indicators; The shadow should not fall on the seats and controls. Flickering light is unacceptable, as it is tiresome for the eyes; the spectral composition of the light must comply with the recommendations of doctors and lighting engineers. If general lighting is insufficient, additional local lighting must be provided.

The minimum dimensions of the workbench are 1200X900 mm; its height should be designed for a tall traffic controller. When working standing, stands of an appropriate design must be provided for shorter-statured traffic controllers. For sitting work, chairs with a seat rotating around a vertical axis, the height of which is adjusted using a screw device, should be used.

The workplace must meet electrical safety requirements. In particular, the place on the workbench where adjustments are made must be made of electrical insulating material. The likelihood of the adjuster touching grounded parts of the workbench during the adjustment process should be minimized. When working with high-voltage equipment, a rubber mat should be placed on the floor under the workbench. The workplace must provide for the possibility of de-energizing the equipment. The housings of measuring instruments must be reliably grounded with wires of the appropriate grades and cross-sections. Grounding wires should be positioned in such a way that the adjuster can see the entire wire from the device body to the place where it is grounded. The power hoses of the devices must be free of exposed wires and frayed insulation and must have plugs that protect the adjuster from electric shock when inserting or removing them from the socket.

In Fig. Figure 2.1 shows one of the possible workplace designs. The structure is prefabricated and consists of standard elements. The angular shape of the workbench and the corresponding arrangement of the instruments expand the viewing angle to 180° and allow the adjuster to work in a more comfortable position than when the instruments are arranged in a line. The left side table contains a power supply with an automatic voltage regulator, and the right side contains drawers for storing tools and parts.

Rice. 2.1. Workplace of a radio-electronic equipment controller.

The presence of an upper shelf mounted on brackets makes it possible to place a larger number of measuring instruments at the workplace.

The selected form of the workbench allows for rational use of production space, while it is possible to arrange workplaces in “crosses” of four or in a line.

The complex work station of a traffic controller (Fig. 2.2) consists of a workbench-1, a rack-2 and a table-trolley 4. From these elements, a number of different layouts of the traffic controller’s workstations can be made. The layout option is selected depending on the dimensions of the controlled product, the number of measuring instruments used and the general layout of workplaces.

Rice. 2.2. Layout of the traffic controller's workplace from separate

functional elements.

The desktop (1200X^50X1200 mm) has a hanging cabinet with four drawers and a hanging power supply, which are interchangeable. The table has two pull-out shelves located on the left and right under the tabletop. For additional placement of measuring equipment on the table there is a folding shelf 3, mounted on vertical posts.

In the non-working position, working documentation can be attached to the shelf.

A trolley table (750X300X780 mm), equal in height to the work table, allows, if necessary, to increase the area of ​​the work table and can be used for delivering and moving instruments and equipment.

The rack is designed to accommodate equipment and is installed at the back or side of the table. The middle shelf of the rack is adjustable and can be installed at desktop height or in any other required position.

The desktop and rack have adjustable supports with rubber thrust bearings. All elements are made using parts of the universal prefabricated frame structures (USCC) system - a rectangular tubular profile and connecting angles. If necessary, the frames of working elements can be disassembled and used in other layouts.

S.r. Topic 1 Testing of electronic equipment

(G.V. Yarochkina. Electronic equipment and instruments. Installation and adjustment, pp. 191-194)

Topic 2 Operating conditions of radio-electronic equipment and instruments and the influence of various factors on the performance of radio equipment.

(G.V. Yarochkina. Radio-electronic equipment and instruments. Installation and adjustment. pp. 194-197)