And again, some general educational material. This time we will talk about base stations. Let's look at various technical points on their placement, design and range, and also look inside the antenna unit itself.
Base stations. General information
This is what cellular antennas look like installed on the roofs of buildings. These antennas are an element of a base station (BS), and specifically a device for receiving and transmitting a radio signal from one subscriber to another, and then through an amplifier to the base station controller and other devices. Being the most visible part of the BS, they are installed on antenna masts, roofs of residential and industrial buildings and even chimneys. Today you can find more exotic options for their installation; in Russia they are already installed on lighting poles, and in Egypt they are even “disguised” as palm trees.
The connection of the base station to the telecom operator’s network can be done via radio relay communication, so next to the “rectangular” antennas of the BS units you can see a radio relay dish:
With the transition to more modern standards of the fourth and fifth generations, to meet their requirements, stations will need to be connected exclusively via fiber optics. In modern BS designs, optical fiber becomes an integral medium for transmitting information even between nodes and blocks of the BS itself. For example, the figure below shows the design of a modern base station, where fiber optic cable is used to transmit data from the RRU (remote controlled units) antenna to the base station itself (shown in orange).
The base station equipment is located in non-residential premises of the building, or installed in specialized containers (attached to walls or poles), because modern equipment is quite compact and can easily fit into the system unit of a server computer. Often the radio module is installed next to the antenna unit, this helps reduce losses and dissipation of power transmitted to the antenna. This is what the three installed radio modules of the Flexi Multiradio base station equipment look like, mounted directly on the mast:
Base station service area
To begin with, it should be noted that there are various types base stations: macro, micro, pico and femtocells. Let's start small. And, in short, a femtocell is not a base station. It is rather an Access Point. This equipment is initially aimed at a home or office user and the owner of such equipment is a private or legal entity. a person other than the operator. The main difference between such equipment is that it has a fully automatic configuration, from assessing radio parameters to connecting to the operator’s network. Femtocell has the dimensions of a home router:
Picocell is BS low power, owned by the operator and using IP/Ethernet as a transport network. Usually installed in places where there is a possible local concentration of users. The device is comparable in size to a small laptop:
A microcell is an approximate version of the implementation of a base station in a compact form, very common in operator networks. It is distinguished from a “large” base station by a reduced capacity supported by the subscriber and lower radiating power. Weight, as a rule, is up to 50 kg and radio coverage radius is up to 5 km. This solution is used where high network capacities and power are not needed, or where it is not possible to install a large station:
And finally, a macro cell is a standard base station on the basis of which mobile networks are built. It is characterized by powers of the order of 50 W and a coverage radius of up to 100 km (in the limit). The weight of the stand can reach 300 kg.
The coverage area of each BS depends on the height of the antenna section, the terrain and the number of obstacles on the way to the subscriber. When installing a base station, the coverage radius is not always brought to the fore. As the subscriber base grows, the maximum may not be enough bandwidth BS, in this case the message “network busy” appears on the phone screen. Then, over time, the operator in this area can deliberately reduce the range of the base station and install several additional stations in places of greatest load.
When you need to increase network capacity and reduce the load on individual base stations, then microcells come to the rescue. In a megacity, the radio coverage area of one microcell can be only 500 meters.
In a city environment, oddly enough, there are places where the operator needs to locally connect an area with a lot of traffic (metro station areas, large central streets, etc.). In this case, low-power microcells and picocells are used, the antenna units of which can be placed on low buildings and on poles street lighting. When the question arises of organizing high-quality radio coverage inside closed buildings(shopping and business centers, hypermarkets, etc.) then picocell base stations come to the rescue.
Outside cities, the operating range of individual base stations comes to the fore, so the installation of each base station away from the city is becoming an increasingly expensive enterprise due to the need to build power lines, roads and towers in difficult climatic and technological conditions. To increase the coverage area, it is advisable to install the BS on higher masts, use directional sector emitters, and lower frequencies that are less susceptible to attenuation.
So, for example, in the 1800 MHz band, the range of the BS does not exceed 6-7 kilometers, and in the case of using the 900 MHz band, the coverage area can reach 32 kilometers, all other things being equal.
Base station antennas. Let's take a look inside
In cellular communications, sector panel antennas are most often used, which have a radiation pattern with a width of 120, 90, 60 and 30 degrees. Accordingly, to organize communication in all directions (from 0 to 360), 3 (pattern width 120 degrees) or 6 (pattern width 60 degrees) antenna units may be required. An example of organizing uniform coverage in all directions is shown in the figure below:
And below is a view of typical radiation patterns on a logarithmic scale.
Most base station antennas are broadband, allowing operation in one, two or three frequency bands. Starting with UMTS networks, unlike GSM, base station antennas are able to change the radio coverage area depending on the load on the network. One of the most effective methods emitted power control is the control of the antenna tilt angle, in this way the irradiation area of the radiation pattern changes.
Antennas can have a fixed tilt angle, or can be remotely adjusted using special software located in the BS control unit and built-in phase shifters. There are also solutions that allow you to change the service area, from common system data network management. In this way, it is possible to regulate the service area of the entire sector of the base station.
Base station antennas use both mechanical and electrical pattern control. Mechanical control is easier to implement, but often leads to distortion of the radiation pattern due to the influence of structural parts. Most BS antennas have an electrical tilt angle adjustment system.
A modern antenna unit is a group of radiating elements of an antenna array. The distance between the array elements is selected in such a way as to obtain the lowest level of side lobes of the radiation pattern. The most common panel antenna lengths are from 0.7 to 2.6 meters (for multi-band antenna panels). The gain varies from 12 to 20 dBi.
The figure below (left) shows the design of one of the most common (but already outdated) antenna panels.
Here, the antenna panel emitters are half-wave symmetrical electric vibrators above the conductive screen, located at an angle of 45 degrees. This design allows you to create a diagram with a main lobe width of 65 or 90 degrees. In this design, dual- and even tri-band antenna units are produced (though quite large). For example, a tri-band antenna panel of this design (900, 1800, 2100 MHz) differs from a single-band one, being approximately twice as large in size and weight, which, of course, makes it difficult to maintain.
An alternative manufacturing technology for such antennas involves making strip antenna radiators (square-shaped metal plates), in the figure above on the right.
And here is another option, when half-wave slot magnetic vibrators are used as a radiator. The power line, slots and screen are made on one printed circuit board with double-sided foil fiberglass:
Taking into account the modern realities of the development of wireless technologies, base stations must support 2G, 3G and LTE networks. And if control units of base stations of networks different generations can be placed in one wiring closet without increasing the overall size, then significant difficulties arise with the antenna part.
For example, in multi-band antenna panels the number of coaxial connecting lines reaches 100 meters! Such a significant cable length and the number of soldered connections inevitably leads to line losses and a decrease in gain:
In order to reduce electrical losses and reduce solder points, microstrip lines are often made; this makes it possible to create dipoles and the power supply system for the entire antenna using a single printed technology. This technology easy to manufacture and ensures high repeatability of antenna characteristics during serial production.
Multiband antennas
With the development of third and fourth generation communication networks, modernization of the antenna part of both base stations and cell phones is required. Antennas should work in new additional bands exceeding 2.2 GHz. Moreover, work in two and even three ranges must be carried out simultaneously. As a result, the antenna part includes quite complex electromechanical circuits, which must ensure proper functioning in difficult climatic conditions.
As an example, consider the design of the emitters of a dual-band antenna of a Powerwave cellular communication base station operating in the ranges 824-960 MHz and 1710-2170 MHz. Her appearance shown in the picture below:
This dual-band irradiator consists of two metal plates. The one that larger size operates in the lower 900 MHz range, above it there is a plate with a smaller slot emitter. Both antennas are excited by slot emitters and thus have a single power line.
If dipole antennas are used as emitters, then it is necessary to install a separate dipole for each wave range. Individual dipoles must have their own power supply line, which, of course, reduces the overall reliability of the system and increases power consumption. An example of such a design is the Kathrein antenna for the same frequency range as discussed above:
Thus, the dipoles for the lower frequency range are, as it were, inside the dipoles of the upper range.
To implement three- (or more) band operating modes, printed multilayer antennas have the greatest technological effectiveness. In such antennas, each new layer operates in a rather narrow frequency range. This “multi-story” design is made of printed antennas with individual emitters, each antenna is tuned to individual frequencies in the operating range. The design is illustrated in the figure below:
As in any other multi-element antennas, in this design there is interaction between elements operating in different frequency ranges. Of course, this interaction affects the directivity and matching of the antennas, but this interaction can be eliminated by methods used in phased array antennas (phased array antennas). For example, one of the most effective methods is to change design parameters elements by displacing the exciting device, as well as changing the dimensions of the irradiator itself and the thickness of the dielectric separating layer.
An important point is that all modern wireless technologies are broadband, and the operating frequency bandwidth is at least 0.2 GHz. Antennas based on complementary structures, a typical example of which are “bow-tie” antennas, have a wide operating frequency band. Coordination of such an antenna with the transmission line is carried out by selecting the excitation point and optimizing its configuration. To expand the operating frequency band, by agreement, the “butterfly” is supplemented with a capacitive input impedance.
Modeling and calculation of such antennas are carried out in specialized CAD software packages. Modern programs allow you to simulate an antenna in a translucent housing in the presence of the influence of various structural elements antenna system and thereby allow for a fairly accurate engineering analysis.
The design of a multi-band antenna is carried out in stages. First, a microstrip printed antenna with a wide bandwidth is calculated and designed for each operating frequency range separately. Next, printed antennas of different ranges are combined (overlapping each other) and their joint operation is examined, eliminating, if possible, the causes of mutual influence.
A broadband butterfly antenna can be successfully used as the basis for a tri-band printed antenna. The figure below shows four various options its configuration.
The above antenna designs differ in the shape of the reactive element, which is used to expand the operating frequency band by agreement. Each layer of such a tri-band antenna is a microstrip emitter of given geometric dimensions. The lower the frequencies, the larger the relative size of such an emitter. Each layer printed circuit board separated from another by a dielectric. The above design can operate in the GSM 1900 band (1850-1990 MHz) - accepts the bottom layer; WiMAX (2.5 - 2.69 GHz) - receives the middle layer; WiMAX (3.3 - 3.5 GHz) - receives top layer. Such a design of the antenna system will make it possible to receive and transmit a radio signal without the use of additional active equipment, thereby not increasing overall dimensions antenna block.
And in conclusion, a little about the dangers of BS
Sometimes, base stations of cellular operators are installed directly on the roofs of residential buildings, which actually demoralizes some of their inhabitants. Apartment owners stop having cats, and gray hair begins to appear faster on grandma's head. Meanwhile, from the installed base station, the residents of this house electromagnetic field they almost don’t receive it, because the base station doesn’t radiate “down.” And, by the way, SaNPiN standards for electromagnetic radiation in the Russian Federation are an order of magnitude lower than in “developed” Western countries, and therefore base stations within the city never operate at full capacity. Thus, there is no harm from BS, unless you sunbathe on the roof a couple of meters away from them. Often, there are a dozen access points installed in residents’ apartments, as well as microwave ovens and cell phones(pressed to your head) have a much greater impact on you than a base station installed 100 meters outside the building.
So, a radio access network of GSM or UMTS standards consists of the N number of base stations. Base stations (BS) are controlled by a BSC/RNC controller or several controllers. User traffic and signaling information from the BS and controllers is delivered to the Core Network, which consists of a switch, transcoders, media gateways, packet switching network access nodes, etc.
Thus, the radio subsystem includes base stations and their controllers, the maintenance of which I am directly involved in. The location of the BS is called the site/site/hardware. Periodically, at certain sites, maintenance work is carried out on the BS, power supply system, transport network equipment, security and fire alarm system, systems automatic fire extinguishing, antenna mast structures and feeder path.
The power supply system consists of an input panel.
Three-phase power supply with the possibility of backup connection from a generator.
Socket for connecting the cable from the mobile generator.
The switchboard contains an electricity meter, additional sockets, surge suppressors and circuit breakers of various ratings for electricity consumers: air conditioners, work and emergency lighting lamps, power supply uninterruptible power supply(UPS), security and fire alarm, heater, exhaust ventilation.
The most important elements of the radio access network are powered from a DC network with a voltage of -48 V, although domestic equipment since Soviet times was designed for a voltage of -60 V. In the event of a power outage, power supply organizations will various reasons There is a backup power supply from rechargeable batteries.
At this facility, 3 Coslight 6-gfm-150x batteries are installed, each with a capacity of 150 Ah. By the way, the batteries in the photo are numbered correctly from the positive terminal to the negative. During battery maintenance, a control discharge is performed using a block of load resistors. Based on the results of the discharge, a conclusion is made as to whether the battery requires replacement or not.
By the way, about the quality of products from China. When checking the tightening torque of the battery jumper bolts, the following was obtained.
The conversion of alternating current to direct current and the maintenance of the battery are controlled by an uninterruptible power supply.
This UPS7-48/218-7 (2.0) has 4 pulse stabilization units installed.
On the UPS indicator we observe a constant voltage with a nominal value of 54.1 V, a load current of 32 A, a battery charging current of 0 A and a temperature on the rack with the battery of +18 degrees Celsius (a temperature sensor is necessary for thermal compensation of the battery content voltage).
Behind the UPS cover there is a number of machines from which wires extend to base stations, radio relay stations (RRS), batteries and other DC consumers. There, on the left, you can see a scarf with contacts for the output of an external alarm about a power outage and low battery.
In this particular case, the site contained a GSM 900 base station manufactured by Alcatel.
Behind the cabinet door is the main equipment: 10 TRAGE transmitters, 3 AGC9E combiners and one SUMA control board. The BS configuration is described as 4/3/3, which means: 4 transmitters operate on the first sector, 3 on the second and third. Each transmitter is connected to a combiner of the assigned sector. From the combiner there are 2 feeders (jumper) to the lightning protection and then upward to the antenna of the selected sector.
On the top of the cabinet there are 2 plinths for external faults, from left to right, a plinth for connecting to the transport network via the A-bis interface (E1 streams), power contacts (blue and black wires) and switches, each on a separate cabinet shelf.
There are 6 jumpers coming out from the top of the BS cabinet (specifically for a three-sector configuration), which are connected through lightning protection to an external feeder path (feeder diameter 7/8 inch).
Lightning protection
The cable entry is hermetically sealed from moisture.
There is a 19" rack installed in the corner. It houses the cross, indoor units PRS and UMTS base station.
The internal unit (IDU) of the PPC is connected to the external unit (ODU) by a black 8D-FB feeder. Cables are connected to 2 IDU connectors, each of which outputs 8 E1 streams to the crossover. Port 1 patch cord is connected to the transport port of the UMTS base station.
The MDP-34MB-25C relay is capable of transmitting 34 Mbit/s of traffic, which is really not enough.
Below is the Ericsson RBS 6601 BS of the UMTS (3G) standard.
External transmitters are connected by an optical cable to the internal unit.
Excess optics are carefully rolled up, packed and mounted on the wall.
View of the equipment room from the entrance.
Opposite side.
Cable rack with main grounding bus (GZSh).
Empty cable rack, hood, air conditioners, bottom left panel with automatic switches for external transmitters (RRU) UMTS base.
Supply ventilation box.
The actual cross plinths.
Heater and fire extinguishers.
Let's see what's outside the BS hardware room. A reinforced concrete pillar was installed as an antenna mast support; the pillars can be a separate story, because they are not designed for real load. In the near future they will be replaced with all-metal supports.
External view of the cable entry. 6 feeders from GSM to antennas, 3 optical cables in a corrugation, 3 black power cables for 3G transmitters, from which thin black grounding cables go to the red bus, a yellow-green wire is the grounding of the external RPC unit.
Anti-ice protection.
Staircase with safety railing.
At the top of the pole there is a metal basket with a superstructure, which is closed by a lightning rod.
Pipe stand and GSM standard BS sector antenna installed on it.
The sector is marked for ease of orientation in case of modernization or elimination of accidents.
Antenna connectors with fixed jumpers. Jumpers are from 1.5 to 3 meters long and 1/2 inch in diameter.
GSM sector antenna label.
A pair of jumpers from the feeders to the antenna.
Marking of feeders using tags.
Feeder grounding.
Grounding points for feeders on metal structures.
Pipe stand with antenna and external RRS unit.
The RRS antenna was marked.
RRL flight, the junction tower is visible in the distance.
Label on external unit RRS.
In the top photo, the leftmost connector is used to connect a voltmeter when adjusting the span; the voltage at this connector is proportional to the level of the received signal from the response relay. The next connector is for connecting ODU and IDU (outdoor unit & indoor unit) with PPC coaxial IF (intermediate frequency) cable. The connector is sealed against moisture getting into the cable. The far right point for grounding the block.
Marking of PPC cables.
The actual mounting for the RRS antenna. Two long screws/studs are used for fine adjustment of the RRL span.
View of the site from above.
RRU - remote radio unit standard UMTS.
What is connected to the RRU? On the left, a thin optical cable extends from the corrugation into the transmitter, inside of which a regular SFP module is installed. The next to be connected is the power cable (also -48 V, DC), to the right is a thin cable for connecting to the RET (Remote Electrical Tilt) - a device that controls the electrical tilt angle of the sector antenna. Next are 2 jumpers to the antenna and a yellow-green ground cable.
It should be explained why cross-polarized antennas are used in both GSM and UMTS. Essentially, the housing contains 2 antennas with different polarizations (usually angles of +45 degrees and -45 degrees), so 2 feeders from the transmitters are connected. In this way, polarization diversity of the signal received from the subscriber is realized.
Label on the UMTS antenna.
RET at the back.
RET from the front of the antenna.
View of the equipment room from above (30 m).
BS of competitors with a climate cabinet, in which everything necessary for work is installed.
After finishing the work, close the hatch to the platform from “vandals”.
We are closing the site fencing...
... we load into the pepelats and go to rest.
I hope this small photo report will show you how a regular mobile communications base station is built and how, approximately, everything is implemented in hardware. I apologize for the quality of the photo, the shooting was carried out during work hours. The post was written for an invite to Habr with the hope of new interesting publications.
P.S. As a suggestion: “There is no disclosure of corporate information in the post!”
P.P.S. Thanks to @FakeFactFelis for the invite.
Today magazine Reconomica brings to your attention an overview and description of the profession “Base Station Maintenance Engineer”. This is exactly the specialist who maintains the operation of towers, and therefore cellular coverage in your area. If you would like to get such a job, this interview with a current engineer at Megafon will tell you about all the pitfalls and help you make a decision on employment.
How to get a job as a service engineer at a cellular operator company
Hello! My name is Egorov Alexey Ivanovich, I’m 33 years old, I’ve been working at Megafon PJSC in one of the largest cities in the Volga region for almost 3 years. My position is called “Service Engineer for Base Stations, Antenna Mast Structures and Large Network Elements.” Simply put, a technician operates communications equipment, namely: antennas, transmitters, radio relay lines, optics and sealing equipment.
To apply for this position you will definitely need higher education, preferably in the field of communications or radio engineering, no fear of heights, a category “B” driver’s license and a decent amount of adventurism in your character. You must also have a passion for electricity, repairing electrical equipment, knowledge in the field of IT, have experience in installing cable lines, and be able to handle tools and a laptop at the level of a network administrator.
Finding such a job is not difficult - all cellular operators have a base station operation department and in their representative offices you can find out where it is located. The most difficult thing is to get into the staff, recruitment for vacant positions is rare, people are carefully selected to suit their temperament, everyone works with enthusiasm, and the team, as a rule, is friendly and united, in other words, “outsiders” are not welcome. And this is all despite your skills and knowledge.
What does a communications engineer do?
If, however, you, a young specialist, a graduate, received employment contract for this position, a whole world of adventures, difficult situations, interesting moments and a lot of positive things! Don’t expect to sit in the office - from the first day you will be taken to the “fields” and shown beautiful places native land, you will have the opportunity to observe everything from a bird's eye view, carry heavy blocks of equipment, tools, and also take part in a quest called “find a base station in a populated area and try to open a door that has sagged on its hinges with a rusty lock,” in general, You will be able to fully realize your resourcefulness.
In winter, of course, it’s disgusting, cold and heavy from winter clothing, feet and hands are freezing from the wild, whipping gusts of wind, even the eyes are freezing, the only thing open place, but this is all nothing compared to the moment when you, with numb fingers, will fasten yourself to the mast structure so that you don’t get blown away, looking in your bag the right tool and, in fact, work. The worst thing in this situation is the fact that, a priori, you will get up and down from the antenna mast structure more than once for various reasons beyond your control, and the fact that you need to go to your car stuck in a forest belt waist-deep in snow for other equipment , which, most likely, also does not support the software you need, and so on until victory, until you complete all the actions according to the law of meanness. Your work can only be assessed by your colleagues, who themselves have found themselves in such situations more than once, however, they come to the rescue willingly, help with deeds, teach and show you everything, all you need on your part is interest and a good memory.
Engineer salary in telecom operator companies
The salary you expect is from 27,000 rubles per month in hand and above, but, of course, not double, it all depends on experience and your desire to devote yourself entirely to work, it consists of a flat salary and an annual bonus in the amount of one to three salaries, the social package is standard, there is voluntary health insurance with a limited but sufficient set, prospects career growth are also available.
In the companies MTS, Megafon, Beeline-Vymplecom, Tele 2, the salaries of technicians are approximately the same.
Pros and cons of being an installation technician
When you are promoted, you will be a fierce professional in your field, with experience in almost everything. technical areas, ingenuity and a strong position in life. You will have to work hard and honestly, stay late at work often, be on alert all the time, with a charged phone, with a clear, consistent plan of action, with full tools necessary for work.
You will learn to drive a car like a god, fortunately, there are a lot of trips and over long distances, study the structure of all the components and assemblies of your iron horse in order to notice a malfunction in time, you will know all the roads well, settlements, borders of your region, spectacular places. The office issues a car and even assigns it to you, but only in working hours, and there will be no time to use it for personal purposes due to lack of time and the workload of its equipment.
One of the advantages of this profession is the fact that you will never gain more weight in your body than normal, strengthen all the veins of the body, train your arms and legs, and develop your lungs. In terms of health hazards - yes, the profession is dangerous, you work at heights, under electromagnetic radiation, sometimes having spent a lot of time under the antennas, you can experience a headache and nausea; driving, you understand, is also unsafe, and working with electricity is dangerous.
Work realities. What you will have to face after getting a job
I hope I didn’t scare the readers with the last paragraph, since harm to health is present in any profession, and all diseases come from nerves. Here you definitely won’t have to be nervous and bored - having screwed on the bolts and nuts at the top of the mast, coiled the rope and safety equipment correctly (you will be taught how to tie knots, use carabiners, pulleys at the level of a climber), descended from the 70-meter mark with an easy, beautiful move, you find yourself in a hardware container in which a corporate laptop is waiting for you with the programs you installed and a million versions of different software that you understand better than Bruce Lee in wushu, you will begin to tinker with the equipment in software, occasionally saying prayers to the Mayan tribe in the hope of finding the right configuration together with your colleagues on a conference call, located in the opposite point of the region from you, and perhaps hanging on the insurance, you finally find one of the right options that will ensure the operation of foreign hardware and people in a godforsaken village begin to post photos on Instagram.
After that, with a feeling of accomplishment and pride, you will go out into the street, get into the car, overcome several mud swamps on your way, with a paranoid feeling that you forgot to turn on something or check at the base station in this village, defend the city traffic jams, pick up your child from kindergarten, go home, read a collective chat on Viber, after that you will realize that you are lucky that you had time to kindergarten, because someone else is working at the bases, twisting, twirling, breaking passwords, but he still has to go home...
In the morning, after the planning meeting, in the smoking room, everyone is joyful and full of enthusiasm, sharing their achievements, telling all the troubles they have been in, and every time they are ready to go and conquer the tasks. This will never clog your nerve lines, teach you to be fair, help people, and allow you to keep your self-esteem at a decent level.
Humor plays a special role in this type of activity. Everyone likes to joke and laugh - from the director of operations to the ordinary basic worker (BS AMS KSE engineer), jokes at first may seem mean, but no one will ever make serious and dangerous mistakes, everyone understands what is at the top, what when working with electricity , and just in a traffic situation, your partner is like your own father.
A separate topic is working with a contractor, of which there are quite a few, they all do almost the same thing under the guidance of an engineer, but their specialization, as a rule, is narrower. The contractors' offices recruit specialists who are not always excellent, and often have no idea how communications equipment works. Which is the subject of constant discussions and the emergence of absurd situations among the engineers of the operation department.
There have been cases where our non-working units were changed by mistake from third-party operators, since often all or several operators use one mast for their equipment, this, as you understand, caused a whole chain of arbitrary events both in our organization and in our colleagues from another telecom operator. There was one case when a contractor, having passed a rope through a block at the top, was using a car on the ground to lift a heavy cabinet onto a pole, the rope suddenly got between the roller and the body of the block, and accordingly the latter jammed, the contractor in the car did not understand the engineer’s actions and did not see, that in this way he gradually tilts the pole, and, on the contrary, increased the speed of raising the equipment. The result was a catapult effect, only on the pole were the contractor’s colleagues, who, clinging to the center of the structure, found themselves in a stupor and desperately called for their comrade to stop this disgrace. Intervening in time, the maintenance employee stopped the movement of the car with short eloquent phrases, took control of the situation and successfully completed the job he started. By the way, none of those present were injured, there was no damage to material assets, they escaped with a good scare, and the story has become legendary.
In conclusion, I would like to say that I love my job, and I wish everyone to find something to their liking, because then the work will bring joy, there will be no boring thoughts about insufficient pay and lack of promotion, and with experience and time, both will definitely come, good luck to everyone!!
