Transoceanic submarine communication cables. How the World Wide Web was created - the Internet (9 photos)

Received a congratulatory telegram from Queen Victoria and sent her a reply message. The first official exchange of messages over the newly laid transatlantic telegraph cable was marked by a parade and fireworks display over New York City Hall. The festivities were overshadowed by a fire that happened for this reason, and after 6 weeks the cable failed. True, even before that he did not work very well - the message of the queen was transmitted within 16.5 hours.

From idea to project

The first proposal, concerning the telegraph and the Atlantic Ocean, was a relay scheme in which messages delivered by ships were to be telegraphed from Newfoundland to the rest of North America. The problem was the construction of a telegraph line along the complex relief of the island.

Seeking help from the engineer in charge of the project attracted the American businessman and financier Cyrus Field, who later became indispensable for the transatlantic cable project. In the course of his work, he crossed the ocean more than 30 times. Despite the setbacks Field faced, his enthusiasm led to success.

The businessman immediately jumped at the idea of ​​a transatlantic telegraph transmission. Unlike terrestrial systems, in which the pulses were regenerated by relays, the transoceanic line had to get by with a single cable. Field received assurances of the possibility of signal transmission over long distances from and Michael Faraday.

William Thompson provided the theoretical basis for this by publishing the inverse square law in 1855. The rise time of a pulse passing through a cable without an inductive load is determined by the time constant RC of a conductor of length L, equal to rcL 2 , where r and c are the resistance and capacitance per unit length, respectively. Thomson also contributed to submarine cable technology. He improved the mirror galvanometer, in which the slightest deviations of the mirror caused by the current were amplified by projection onto a screen. Later, he invented a device that registers signals with ink on paper.

Submarine cable technology was improved after the appearance in England in 1843 of the resin of a tree native to the Malay Peninsula, which was an ideal insulator because it was thermoplastic, softened when heated, and returned to a solid form when cooled, making it easier to insulate the conductors. Under conditions of pressure and temperature at the bottom of the ocean, its insulating properties improved. Gutta-percha remained the main insulation material for submarine cables until the discovery of polyethylene in 1933.

Field projects

Cyrus Field led 2 projects, the first of which failed, and the second ended in success. In both cases, the cables consisted of a single 7-core wire surrounded by gutta-percha and armored with steel wire. Tarred hemp provided corrosion protection. The nautical mile of the 1858 cable weighed 907 kg. The 1866 transatlantic cable was heavier, at 1,622 kg/mile, but because it had more volume, it weighed less in the water. The tensile strength was 3 t and 7.5 t, respectively.

All cables had a single water return conductor. Although sea ​​water less resistance, it is subject to stray currents. Power was supplied by chemical current sources. For example, the 1858 project had 70 elements of 1.1 V each. These voltage levels, combined with improper and careless storage, caused the deep sea transatlantic cable to fail. The use of a mirror galvanometer made it possible to use lower voltages in subsequent lines. Since the resistance was approximately 3 ohms per nautical mile, at a distance of 2000 miles, currents of the order of a milliamp, sufficient for a mirror galvanometer, could be carried. In the 1860s, a bipolar telegraph code was introduced. The dots and strokes of the Morse code have been replaced with pulses of opposite polarity. Over time, more complex schemes have been developed.

Expeditions 1857-58 and 65-66

To lay the first transatlantic cable, £350,000 was raised by issuing shares. The American and British governments guaranteed a return on investment. The first attempt was made in 1857. It took 2 steamships, Agamemnon and Niagara, to transport the cable. The electricians approved a method in which one ship laid a line from a shore station and then connected the other end to a cable on another ship. The advantage was that it maintained a continuous electrical connection with the shore. The first attempt ended in failure when the cable-laying equipment failed 200 miles offshore. It was lost at a depth of 3.7 km.

In 1857, Niagara's chief engineer, William Everett, developed new cable-laying equipment. A notable improvement was an automatic brake that worked when the tension reached a certain threshold.

After a strong storm, which almost sank the Agamemnon, the ships met in the middle of the ocean and on June 25, 1858 began to lay transatlantic cable again. "Niagara" moved to the west, and "Agamemnon" - to the east. 2 attempts were made, interrupted by damage to the cable. The ships returned to Ireland for his replacement.

On July 17, the fleet again set off to meet each other. After minor hiccups, the operation was a success. Going at a constant speed of 5-6 knots, on August 4, the Niagara entered Trinity Bay on. Newfoundland. On the same day, the Agamemnon arrived at Valentia Bay in Ireland. Queen Victoria sent the first welcome message described above.

The expedition of 1865 ended in failure 600 miles from Newfoundland, and only an attempt in 1866 was successful. The first message on the new line was sent from Vancouver to London on July 31, 1866. In addition, the end of a cable lost in 1865 was found, and the line was also successfully completed. The transmission speed was 6-8 words per minute at a cost of $10/word.

Telephone communications

In 1919, the American company AT&T initiated a study of the possibility of laying a transatlantic telephone cable. In 1921 a deep water telephone line was laid between Key West and Havana.

In 1928, it was proposed to lay a cable without repeaters with a single voice channel across the Atlantic Ocean. High price project ($15 million) at the height of the Great Depression, and improvements in radio technology interrupted the project.

By the early 1930s, advances in electronics made it possible to create a submarine cable system with repeaters. The requirements for the design of intermediate link amplifiers were unprecedented, since the devices had to operate uninterruptedly on the ocean floor for 20 years. Strict requirements were imposed on the reliability of components, in particular vacuum tubes. In 1932, there were already electric lamps that successfully passed the test for 18 years. The radio elements used were significantly inferior to the best samples, but they were very reliable. As a result, TAT-1 worked for 22 years, and not a single lamp failed.

Another problem was the laying of amplifiers in the open sea at a depth of up to 4 km. When the ship is stopped to reset the repeater, kinks can occur on the cable with helical armor. As a result, a flexible amplifier was used, which could fit equipment designed for telegraph cable. However, the physical limitations of the flexible repeater limited its throughput to a 4-wire system.

British Post has developed an alternative approach with rigid repeaters of much larger diameter and capacity.

Implementation of TAT-1

The project was restarted after World War II. In 1950, flexible amplifier technology was tested by a system linking Key West and Havana. In the summer of 1955 and 1956, the first transatlantic was laid between Oban in Scotland and Clarenville on about. Newfoundland, well north of existing telegraph lines. Each cable was about 1950 nautical miles long and had 51 repeaters. Their number was determined by the maximum voltage at the terminals that could be used for power without affecting the reliability of high-voltage components. The voltage was +2000 V at one end and -2000 V at the other. The bandwidth of the system, in turn, was determined by the number of repeaters.

In addition to repeaters, 8 subsea equalizers were installed on the east-west line and 6 on the west-east line. They corrected the accumulated shifts in the frequency band. Although the total loss in the 144 kHz bandwidth was 2100 dB, the use of equalizers and repeaters reduced this to less than 1 dB.

Getting started TAT-1

In the first 24 hours after launch on September 25, 1956, 588 calls were made from London and the USA and 119 from London to Canada. TAT-1 immediately tripled the capacity of the transatlantic network. The frequency band of the cable was 20-164 kHz, which made it possible to have 36 voice channels (4 kHz each), 6 of which were divided between London and Montreal and 29 between London and New York. One channel was intended for the telegraph and service.

The system also included a land link through Newfoundland and a submarine link to Nova Scotia. The two lines consisted of a single 271 nautical mile cable with 14 rigid repeaters designed by UK Post. The total capacity was 60 voice channels, 24 of which connected Newfoundland and Nova Scotia.

Further improvements to the TAT-1

The TAT-1 line cost $42 million. The $1 million per channel spurred the development of terminal equipment that would use bandwidth more efficiently. The number of voice channels in the standard 48 kHz frequency range has been increased from 12 to 16 by reducing their width from 4 to 3 kHz. Another innovation was temporal speech interpolation (TASI) developed at Bell Labs. TASI allowed for doubling the number of vocal circuits thanks to pauses in speech.

Optical systems

The first transoceanic optical cable TAT-8 was put into operation in 1988. Repeaters regenerated pulses by converting optical signals into electrical ones and vice versa. Two working pairs of fibers worked at a speed of 280 Mbps. In 1989, thanks to this transatlantic Internet cable, IBM agreed to fund a T1 level link between Cornell University and CERN, which greatly improved the connection between the American and European parts early internet.

By 1993, more than 125,000 km of TAT-8s were in operation worldwide. This figure almost corresponded to the total length of analog submarine cables. In 1992, TAT-9 entered service. The speed per fiber has been increased to 580 Mbps.

technological breakthrough

In the late 1990s, the development of erbium-doped optical amplifiers led to a quantum leap in the quality of submarine cable systems. Light signals with a wavelength of about 1.55 microns can be directly amplified, and the throughput is no longer limited by the speed of the electronics. The first optically enhanced system to fly across the Atlantic Ocean was TAT ​​12/13 in 1996. The transmission rate on each of the two fiber pairs was 5 Gbps.

Modern optical systems allow such large amounts of data to be transmitted that redundancy is critical. Typically, modern fiber optic cables such as TAT-14 consist of 2 separate transatlantic cables that are part of a ring topology. The other two lines connect coast stations on each side of the Atlantic Ocean. Data is sent around the ring in both directions. In the event of a break, the ring will self-repair. Traffic is transferred to spare pairs of fibers in the working cables.

Regarding the laying by Google of its own fiber-optic communication cable along the bottom of the Pacific Ocean, which will connect the company's data centers in Oregon, USA, with Japan. It would seem that this is a huge project worth $ 300 million and 10,000 km long. However, if you dig a little deeper, it becomes clear that this project is outstanding only because it will be done by one media giant for personal use. The whole planet is already tightly entangled with communication cables and there are much more of them under water than it seems at first glance. Having become interested in this topic, I prepared a general educational material for the curious.

Origins of intercontinental communication

Cable device

• Durability
• Be waterproof (suddenly!)
• Withstand the enormous pressure of water masses above oneself
• Have sufficient strength for installation and operation
• Cable materials must be selected so that mechanical changes (stretching of the cable during operation / laying, for example) do not change its performance

The working part of the cable we are considering, by and large, does not differ in anything special from ordinary optics. The whole essence of deep-sea cables lies in the protection of this very working part and the maximum increase in its service life, as can be seen from the schematic drawing on the right. Let's take a look at the purpose of all structural elements in order.

Polyethylene- the outer traditional insulating layer of the cable. This material is an excellent choice for direct contact with water, as it has the following properties:
Resistant to water, does not react with alkalis of any concentration, with solutions of neutral, acidic and basic salts, organic and inorganic acids, even with concentrated sulfuric acid.

The world ocean contains, in fact, all the elements of the periodic table, and water is a universal solvent. The use of such a common in chem. In the industry, a material like polyethylene is logical and justified, since, first of all, the engineers needed to exclude the reaction of the cable and water, thereby avoiding its destruction under the influence of the environment. Polyethylene was used as an insulating material during the laying of the first intercontinental telephone lines in the middle of the 20th century.
However, due to its porous structure, polyethylene cannot provide complete waterproofing of the cable, so we move on to the next layer.

Mylar film- synthetic material based on polyethylene terephthalate. Has the following properties:
Has no smell, taste. Transparent, chemically inactive, with high barrier properties (including many aggressive environments), tear resistant (10 times stronger than polyethylene), wear and impact. Mylar (or Lavsan in the USSR) is widely used in industry, packaging, textiles, and the space industry. They even make tents out of it. However, the use of this material is limited to multilayer films due to heat seal shrinkage.

After a layer of mylar film, you can find cable reinforcement different power, depending on the declared characteristics of the product and its intended purpose. A strong steel braid is mainly used to give the cable sufficient rigidity and strength, as well as to resist aggressive mechanical influences from outside. According to some data circulating on the net, EMP from cables can attract sharks that gnaw through the cables. Same on great depths ah, the cable is simply laid on the bottom, without digging a trench, and fishing vessels can hook it with their gear. To protect against such influences, the cable is reinforced with a steel braid. The steel wire used in the reinforcement is pre-galvanized. The cable reinforcement can take place in several layers. The main task of the manufacturer during this operation is the uniformity of force during the winding of steel wire. With double reinforcement, winding occurs in different directions. If the balance is not observed during this operation, the cable may spontaneously twist into a spiral, forming loops.

As a result of these measures, the mass of a running kilometer can reach several tons. "Why not light and strong aluminum?" many will ask. The whole problem is that aluminum has a stable oxide film in air, but when it comes into contact with sea water, this metal can enter into an intense chemical reaction with the displacement of hydrogen ions, which have a detrimental effect on that part of the cable for which everything was started - optical fiber. That's why steel is used.

aluminum water barrier, or a layer of aluminum polyethylene is used as another layer of waterproofing and cable shielding. Aluminum-polyethylene is a combination of aluminum foil and polyethylene film, interconnected by an adhesive layer. Gluing can be either one-sided or two-sided. On the scale of the entire structure, aluminum-polyethylene looks almost invisible. The thickness of the film may vary from manufacturer to manufacturer, but, for example, one of the manufacturers in the Russian Federation has a final product thickness of 0.15-0.2 mm with one-sided sizing.

Polycarbonate layer reused to reinforce the structure. Lightweight, durable and resistant to pressure and shock, the material is widely used in everyday products such as bicycle and motorcycle helmets, also used as a material in the manufacture of lenses, CDs and lighting products, the sheet version is used in construction as a light-transmitting material. Has a high coefficient of thermal expansion. It was also used in the production of cables.

Copper or aluminum tube is part of the core of the cable and serves to shield it. Other copper tubes with fiber optics inside are placed directly into this design. Depending on the design of the cable, there may be several tubes and they can be intertwined in various ways. Below are four examples of cable core organization:

Laying the optical fiber in copper tubes filled with a hydrophobic thixotropic gel, and metal structural elements are used to organize remote power supply of intermediate regenerators - devices that restore the shape of an optical pulse, which, propagating through the fiber, undergoes distortion.

The cut looks something like this:

Cable production

Cabling

Actually, from the GIF, the laying process becomes extremely clear.

The laying of fiber optic cable on the sea / ocean floor runs continuously from point A to point B. The cable is laid in bays on ships and transported to the place of descent to the bottom. These bays look, for example, like this:

If it seems to you that it is small, then pay attention to this photo:

After the ship goes to sea, it remains exclusively technical side process. A team of stackers with the help of special machines unwinds the cable at a certain speed and, maintaining the necessary cable tension due to the movement of the ship, moves along a pre-laid route.

From the outside it looks like this:

In case of any problems, breaks, or damages, special anchors are provided on the cable, which allow you to raise it to the surface and repair the problem section of the line.

And, in the end, thanks to all this, we can comfortably and at high speed watch photos and videos with cats from all over the world on the Internet.

In the comments to an article about the Google project, the user

Youth Technique No. 1 1937

In the first half 19th century the electric telegraph appeared. Its appearance was caused by the development of the machine industry and the gigantic expansion of the world market. Capitalism needed reliable and fast communication. The telegraph quickly won universal recognition and became an indispensable means of business relations and international speculation.

Naturally, the question soon arose of the need to establish a telegraph connection between the Old and New Worlds - between Europe and America. Wheatstone's automatic machines and Yuz's direct-printers were already working on the telegraph lines, and communication from America to Europe was still carried out by steamboats in 20 days. With such increased international relations, such slowness was completely unbearable.

The question of how to establish electrical communication across the vast expanses of the Atlantic Ocean separating Europe and America has been worrying the minds of scientists, technicians and inventors since the early forties. Back in those days, the American inventor of the writing telegraph

Samuel Morse expressed his confidence that it was possible to lay a telegraph wire along the bottom of the Atlantic Ocean. It took, however, more than twenty years of hard work and titanic efforts associated with overcoming extraordinary difficulties before people were able to connect both continents by telegraph.

The first idea about underwater telegraphy came from the English physicist Wheatstone, who in 1840 proposed his project of connecting England and France by telegraph communication. His idea was, however, rejected as unworkable. In addition, at that time they still did not know how to insulate wires so reliably that they could conduct electric current while at the bottom of the seas and oceans.

The situation changed after the substance, gutta-percha, newly discovered in India, was brought to Europe, and the German inventor Werner Siemens proposed covering wires with it for insulation. Gutta-percha is the most suitable for insulating underwater wires, because, oxidizing and shrinking in the air, it does not change at all in water and can remain there for an indefinitely long time. Thus, the most important issue of the insulation of underwater wires was solved.

In 1847, the English engineer John Brett received from the French government a concession to build an underwater telegraph line between France and England, but he failed to complete the work on time and lost the concession. It was renewed in 1849, and this time Brett undertook to open a message by September 1, 1850. The need for fast electrical communication between both countries was so great and the establishment of this connection promised such large profits that Brett was able to establish a joint-stock company without much difficulty and raise the necessary capital for his enterprise.The cable, made in England, consisted of two copper wires, each 2 mm wide.The wires were covered for insulation with a thick gutta-percha sheath.

On August 23, 1850, a special ship Goliath with a tugboat went to sea to lay the cable.

Their path lay from Dover to the shores of France. The warship Vigdeon was ahead, pointing the Goliath and the tugboat to a predetermined path, marked by buoys with flags fluttering on them.

Everything went well. A cylinder mounted on board the ship, on which the cable was wound, was evenly unwound, and the wire was immersed in water. Every 15 minutes, a load of 10 kilograms of 4 lead was hung from the wire so that it would sink to the very bottom. On the fourth day, the Goliath reached the French coast, the cable was brought to land and connected to a telegraph apparatus. A 100-word welcome telegram was sent to Dover via a submarine cable. The huge crowd that had gathered in Dover at the offices of the telegraph company, and eagerly awaited news from France, greeted the birth of submarine telegraphy with great enthusiasm.

Alas, these delights were premature! The first telegram, transmitted by submarine cable from the French coast to Dover, was also the last. The cable suddenly stopped working. Only after some time did they find out the reason for such a sudden damage. It turned out that some French fisherman, throwing a net, accidentally hooked the cable and tore a piece out of it. But, as they say, there is no evil without good. This accident, oddly enough, contributed to the further improvement and improvement of the technique of laying submarine cables. Electrical engineers who examined a piece of cable found by a fisherman, which had already been on the ocean floor, found that the gutta-percha insulation was too thin, that the cable was not protected from mechanical damage, and that, in general, significant changes should be made to its structure.

But still, despite the first failure, even the most ardent skeptics believed in underwater telegraphy. John Brett organized a second joint-stock company in 1851 to continue the business. This time, the experience of the first laying was already taken into account, and the new cable was arranged according to a completely different pattern. It consisted of four copper wires, each of which was surrounded by a gutta-percha sheath six millimeters thick. All copper wires, together with five round hemp cords tarred and saturated with lard, were twisted into one cable, already wrapped around a common hemp tarred cord. Another hemp layer was applied on top, and all this was wrapped around ten galvanized iron wires with a diameter of seven millimeters for strength and protection against mechanical damage. How much this cable differed from the first one can be seen at least from the fact that it weighed 166 tons, while the weight of the first cable did not exceed the first, it can be seen at least from the fact that it weighed 166 tons, while the weight of the first cable did not exceeded 14 tons.

This time the venture was a complete success. The special ship that laid the cable made its way from Dover to Calais without much difficulty, where the end of the cable was connected to a telegraph machine installed in a tent right on the coastal cliff.

A year later, on November 1, 1852, a direct telegraph service was established between London and Paris. Soon England was connected by submarine cable to Ireland, Germany, Holland and Belgium. Then; the telegraph connected Sweden with Norway, Italy with Sardinia and Corsica. In 1854-1855. a submarine cable was laid across the Mediterranean and Black Sea. Through this cable, the command of the allied forces besieging Sevastopol communicated with their governments.

After the success of these first submarine lines, the question of laying a cable across the Atlantic Ocean to connect America with Europe by telegraph communication was already practically raised. The energetic American businessman Cyros Field, who in 1856 formed the transatlantic company". Before embarking on a grand undertaking, Field contacted the most prominent experts in telegraphy, who had to resolve a number of important and still obscure technical issues. Unexplained was, in particular, the question of whether the electric current can run a huge distance of 4-5 thousand kilometers separating Europe from America. Veteran telegraph business Samuel Morse answered this question in the affirmative. For greater certainty, Field turned to the British government with a request to connect all the wires at his disposal into one line and pass current through them. The British government, vitally interested in the success of Field's enterprise, granted his request, and on the night of December 9, 1856, all the air, underground and underwater wires of England and Ireland were connected into one continuous circuit 8 thousand kilometers long. That "easily" passed through the huge chain, and there was no more doubt on this side.

At the same time, Field found out the nature and direction of the future "route" of the transatlantic cable. In this regard, Lieutenant Maury rendered him a great service, supervising, on the instructions of the American government, the study of the deep currents of the Atlantic Ocean and the temperature regime of its lower layers. Morey reported that in the middle of the ocean there was a vast underwater highland stretching between Ireland and Newfoundland. Of course, on this hill, it is most convenient to lay the cable. Maury also pointed out that, according to his numerous observations, the most favorable time of the year, when the oceanic plains are calm, is the beginning of August.

Having collected all the necessary preliminary information, Field began in February 1857 to manufacture the cable. The cable “consisted of a seven-wire copper rope with a gutta-percha sheath. Its cores were lined with tarred hemp, and on the outside the cable was still wrapped with 18 cords of 7 iron wires each. In this form, a cable 4 thousand kilometers long weighed three thousand tons. This means that in order to transport railway a train of 183 freight wagons would be needed.

On August 6, 1857, a flotilla of ships loaded with cable moved from Valencia (in Ireland) towards Newfoundland. At first everything went well. Ships. slowly moved forward, laying the cable at a speed of three and a half kilometers per hour, but soon (some ten kilometers from the coast, due to the sailor’s oversight, the cable broke. Since it was still not deep, by the end of the next day it was possible to remove the broken end from the water , connect it with the rest of the cable and move on.

On August 11, during a strong storm, the second break of the “cable” occurred, when about 540 kilometers had already been laid. This time, due to the great depths, it was not possible to extract the broken end from the bottom of the ocean. The remaining cable was no longer enough to lay between the two continents. The ships returned to England, and the case had to be started anew.

They went through the whole old cable, cut out all the bad places from it and prepared a new piece of cable 1,350 kilometers long.

But the true cause of the malfunction was found out many years later and it consisted in insufficiently careful soldering (the entire cable consisted of about two thousand separate pieces and had the same number of solderings).

Around the same time, the second submarine cable from Suez to Indigo, more than 5 thousand kilometers long, ceased to operate.

All this forced the British government to temporarily stop issuing further concessions for the installation of an underwater telegraph between America and Europe. A special commission was appointed to develop standards for the manufacture and laying of cables. The commission completed its work in April 1861, and its conclusions served as the basis for all further underwater telegraphy.

Meanwhile, the same tireless Cyroe Field organized a company to once again try to lay a cable across the unyielding ocean. The new "cable" manufactured by the company consisted of a seven-wire cord insulated with four layers. Between the wire and the inner gutta-percha sheath, as well as between the other layers of gutta-percha, a layer of a special composition was laid, closely binding the wire and sheath together and eliminating the appearance of air bubbles. The wire itself was made of better copper than before, and was twice as thick as before.Outside, the cable was covered with a layer of "tarred hemp and wrapped with ten steel wires. A special ship"Great Eastern"was adapted for laying the cable - in the past, a well-equipped ocean-going steamer, did not cover the costs of passenger traffic and removed from flights.

On July 3, 1865, the Great Eastern, accompanied by two English warships, went to sea, having previously connected the end of the cable to a special telegraph station built on the coastal cliffs of Valencia. This station was connected to the entire Irish and European network, and thus, during its entire voyage, the Great Eastern could send telegraphic messages to Europe about the progress of work. On board the ship were first-class scientific and technical forces who carefully monitored the laying of the cable. By the way, the famous English physicist William Thomson (Lord Kelvin), who subsequently designed a special receiving apparatus for the transatlantic telegraph, was on the Great Eastern as an electrical engineer.

The very next day after sailing from the Great Eastern, electrical engineers discovered that the current had stopped flowing through the cable. The steamer, having performed an extremely difficult and dangerous maneuver, during which the cable almost broke, made a full turn and began to rewind the cable already lowered to the bottom. Soon, when the cable began to rise from the water, everyone noticed the cause of the damage: a sharp iron rod was pierced through the cable, touching the gutta-percha insulation.

The same story repeated itself five days later, when 1300 kilometers had already been covered. Only later it turned out that there was no evil will here, and the damage to the cable occurred solely due to technical oversight - the outer steel wire bent in some places, and during rapid rotation metal cylinder these bent ends were pressed into the cable.

For the same reason, the cable failed for the third time. It happened on August 2, when the Great Eastern had already passed about two-thirds of its way. When they began to lift the cable back from a depth of 4 thousand meters, it broke off from a strong tension and drowned. The captain of the Great Eastern Anderson, who had extensive experience in laying cables from the Mediterranean Sea, decided this time not to yield the cable to the ocean, but to extract it from a 4-kilometer depth to the surface of the water and, having soldered it to the end remaining on the ship, continue laying.

The longest ropes were lowered into the water, to which anchors with open paws were tied. The steamer was sent across the cable laying line in the hope that the anchors dragged along the ocean floor would hook the cable and lift it to the surface. Several times the anchors really caught the cable, lifted it up, but each time the cable could not withstand the enormous weight - and the cable, together with the anchors holding it, plunged back into the ocean. Finally, when the reserves of ropes and anchors were exhausted, and there was just enough fresh water and coal left to get to England. The Great Eastern headed for Valencia.

After telegraph communication with the Great Eastery was interrupted on August 2 due to damage to the cable, there was no news of the expedition in England. The country was seized with anxiety for the fate of the brave crew. This completely natural human feeling was accompanied, as is the custom in capitalist countries, with disgusting stock trading and speculation. The shares of the transatlantic telegraph society were rapidly falling in price, they were gradually bought up on the cheap by clever businessmen who understood that, thanks to the technical experience accumulated over many years of failure, the cable would soon be laid.

Even before the return of the Great Eastern to England, the company decided to make a new cable and with the same energy to continue efforts to organize a telegraphic communication between the Old and New Worlds. And the return of the Great Eastern further strengthened the position of supporters of the continuation of work.

The company produced a new cable, much improved over the previous one. The Great Eastern was equipped with new cable-laying machines, as well as special devices designed to lift the cable from the bottom. The new expedition set off on July 7, 1866. This time, the daring undertaking was crowned with complete success: the Prate Eastern reached the American coast, finally laying a telegraph cable across the ocean. This “cable operated almost without interruption for seven years.

The human will and technology defeated the elements. On August 9, the Prate Eastern steamer, accompanied by two other ships, the Albany and the Medway, set off into the ocean to the place where the end of the previous cable had been thrown. Despite the availability of sufficient materials and special machines for lifting the cable, this undertaking proved to be very difficult and complex. Several times it was possible to hook the cable with anchors and lift it up, but the cable invariably broke and fell into the water again.

Only on September 2, after much effort, all three ships simultaneously picked up the cable and carefully began to lift it. This time, the enormous weight of the cable was distributed among three steamers, and it was successfully brought to the surface. Immediately in Europe, where for more than three weeks they had no news of the Great Eastern, the joyful news of the favorable progress of work was transmitted. So, the cable, which rested for about a year at the bottom of the ocean, worked perfectly. He was soldered to the cable that was available on the Great Eastern, and the ship again headed for Newfoundland, which she safely reached on September 8th. Thus, in just a month and a half, two telegraph lines were laid across the Atlantic Ocean between Europe and America.

The third transatlantic cable was laid by the Anglo-American Telegraph Company in 1873. It connected the Petit Minon near Brest in France with Newfoundland. Over the next 11 years, the same company laid four more cables between Valencia and Newfoundland. In 1874, a telegraph line was built connecting Europe with South America. .Minin this begins in Lisbon, then goes through the sharp Ml Deru and the Cape Verde Islands and ends in Pernambuco in Brazil. Another cable in the same direction was completed in 1884.

After the world imperialist war, 20 submarine cables operated between America and Europe. Despite such a large number of wires and the radio communication established between both continents, telegraph traffic increased so much that it was necessary to lay two more improved cables. They were wrapped with a thin tape of permalloy, a special alloy of iron and nickel, which allows several times to increase the speed of signal transmission over the cable.

In 1809, that is, three years after the laying of a submarine cable across the Atlantic Ocean, the construction of another grandiose telegraph enterprise, the Indo-European line, was completed. This line connected Calcutta with London by double wire. Its length is 10 thousand kilometers.

Much later than across the Atlantic, a telegraph cable was laid across the entire Great Ocean. Back in the 19th century, India was connected to Australia by a submarine cable, but it was not until October 31, 1902 that the connection between Canada and Australia was completed by a "cable about 1,000 kilometers long. Prior to this, a telegram from Canada to Australia had to go across the Atlantic Ocean to England, and from here - go further east across the Red Sea east coast Africa, undergoing dozens of retakes in various countries.

So the telegraph network truly entangled the entire globe. In 1898, the length of all telegraph lines reached 318 thousand kilometers. And in 1934 this figure increased. There were 643,000 kilometers of telegraph lines this year in all countries.

Materials: Youth Technique No. 1 1937

The first transatlantic cables - when did they appear and how did they work?

• History of IT,
• network hardware

Sometimes it seems that all these “your internets” have always existed. Cellular communication, Internet, instant exchange of information between users of different countries and continents. But this is not so - after all, even in the 19th century the world was rather isolated, separate parts of the world communicated little with each other. In the second half of the century, the telegraph began to develop, penetrating into all spheres of life of people of that time. But initially, the speed of information transfer across the ocean was equal to the speed of the ocean itself. fast ship of that time, which transported letters and parcels - while we must not forget that after the sea voyage, messages were distributed by land services.

Telegraph companies and businessmen associated with them hoped to lay the first transatlantic cable by 1850. But all these plans looked too fantastic - at least until Cyrus West Field got down to business. By the age of 30, he had accumulated considerable capital, retired and decided to invest in a transatlantic cable project, stretching from Newfoundland to Ireland.



Samples of cables from 1858, 1865 and 1866 that formed the transatlantic link

Here is a cable from 1865, a model of a harpoon and a steel cable of that time.

The project began to be implemented, but problems immediately began. The first cable burst after a few kilometers, because the engineer responsible for laying the cable stopped the reel while the ship was moving. It took several expeditions to complete the laying, which was done by 1858. The completion of the project was welcomed by Queen Victoria (she sent a telegram on August 16 "Her Majesty wishes to congratulate the President on the successful completion of this great international project in which the Queen took a deep interest") and President Buchanan. In fact, everything did not work very well - the cable did not allow data to be transferred quickly, a message of 96 words was transmitted for several hours. The quality of the connection quickly deteriorated, and even the transmission of one word already took about an hour. A month later, the line simply died due to the main power engineer. He applied 2000 volts to the line, and the cable became unusable.

The same samples from the illustration of the book "Great Inventions" in 1932

New cables were laid. Thanks to a better selection of personnel (technicians, engineers), the laying of the cables was also more successful, and the line itself worked much better than before, although its structure and the cables themselves were similar. Already by 1870 there were many cables, a whole web of lines had formed.

TAT-1: Can you hear me?

Although technology developed very rapidly, with the addition of telephone service in 1870, the first transatlantic telephone system did not appear until 1956. The system was named TAT-1. Such a long period may seem strange, but still it should be remembered that telephone communication is more complicated than telegraph, and laying 2800 km of telephone wire so that the line can be used is not an easy task.

The first underwater telegraph cables were simple - copper conductors were insulated and protected from water using natural materials like gutta-percha. The cables were also armored with steel cable. But the bandwidth of a telephone line must be much higher than the bandwidth of a telegraph line, and the conductors running parallel to each other in the cable did not provide optimal conditions for data transmission. Therefore, other types of cables were created - for example, coaxial, which are not very expensive and allow for greater bandwidth.

The TAT-1 system included two cables - one for linking west and east, and the other for feedback. The cable consisted of a central conductor, a polyethylene dielectric, and several layers of copper foil. It was both signal protection and protection from marine animals (the so-called marine worms, etc.). The coaxial cable was wrapped in a fabric winding and jute with a water-proof impregnation. Then all this was enclosed in steel wire armor. Closer to the shore, the cable was armored even more, to protect against anchors and trawls.

The cables were equipped with flexible built-in repeaters to amplify the signal at intervals of 69 km. The size of each repeater was 2.5 meters, and included three vacuum tubes, protected from pressure at a depth of 8000 m. The repeaters provided a signal of 65 dB and a frequency of 144 kHz. It was decided to use vacuum tubes even though the repeaters themselves were developed at Bell Labs, where transistors were also developed (at about the same time). It was considered unproven that a transistor could provide the same high-quality performance as a lamp. Perhaps the decision was correct - not one of the hundreds of lamps failed in 22 years of cable operation.

After TAT-1 was commissioned, the cable ensured the operation of 36 lines - 35 telephone channels with a bandwidth of 4 kHz and 22 telegraph channels for 36 lines. A little later, the number of channels increased to 51. In 1963, a teletype line between Moscow and Washington was launched, it also passed through TAT-1. The TAT-1 backbone worked until 1978, and during this time other alternatives and cable standards appeared. All TAT cables have been decommissioned except for TAT-14, a 9.38 Tb/s fiber optic cable commissioned in 2001.

It is customary to think that the world information web is something intangible. And partly it is. The atmosphere of the planet over the past hundred years has turned from a banal mixture of nitrogen and oxygen into a thick broth of radio waves. But do not be mistaken - each bit of information, before becoming ethereal electromagnetic radiation, necessarily makes a long way along the wires, most of which are laid along the ocean floor.

Attempts to connect the continents by wires began in the very first years after the invention of the telegraph itself. In 1840, the English professor Wheatstone submitted to Parliament a project for laying an underwater cable from Dover to the French coast, but did not receive the consent of the legislators and, accordingly, the money.

Two years later, the inventor of the most common version of the telegraph, Samuel Morse, connected the shores of New York Bay with a cable and transmitted a message through it. Then he predicted that in a short time the telegraph would connect old light with New. A decade later, a company of brothers John and Jacob Brett launched a telegraph service between England and France, laying a solid copper wire, clad in gutta-percha and steel braid, under the waters of the English Channel.

Nexans Skaggerak is a specialized vessel built in 1976 by the Norwegian company Øgreys Mekaniske Verksted for underwater laying of power cables and hose lines. In March 2010, she was upgraded at the Cammell Laird repair docks in Birkenhead, England. The vessel was sawn across, and an additional section 12.5 meters long was welded between its two halves. The Skagerrak also received a new turntable. On the right in the photo, a power cable intended for laying in the sea comes from the shore along a special conveyor that excludes too sharp bends, and is stored in a special cylindrical compartment. A modern submarine power cable may have a diameter on the order of 100 mm. A meter of such a “string” may well pull a couple of tens of kilograms, so it’s no wonder that several hefty workers are required to control the laying. Below in the photo - the turntable mounted on the Skagerrak has a diameter of 29 meters and a payload of 7000 tons, with a volume of 2000 cubic meters.

The man who connected the Old and New World, was the American businessman Cyrus Field, who founded the New York-Newfoundland and London Telegraph Company in 1854. Samuel Morse, known to us, became vice-president. The laying of the cable began in 1857 with the assistance of the governments of the United States and Great Britain, which provided warships for use as cable layers: the steam frigate Niagara and the sail-steam battleship Agamemnon. 620 km of cable was laid on the bottom of the Atlantic, after which it broke off.

The next attempt was made a year later - "Niagara" and "Agamemnon", connecting the ends of the cable in the middle of the ocean, set off in different directions. After several breaks, the ships returned to Ireland for resupply. The next start - in July of the same year - brought success, which few people had hoped for. But ... the telegraph worked for about a month and fell silent.

The indefatigable Field returned to his idea in 1865, chartering the largest ship of that time, the Great Eastern, as a cable-laying ship. Three-quarters of the line was laid from it to the bottom, when on August 2 the cable broke again and went to the bottom. Finally, in 1866, the telegraph line crossed the Atlantic, and at the very beginning of the last century, the boundless Pacific Ocean.

Until the 1930s, the main problem of intercontinental communications was the poor quality of the insulation. The main materials for its manufacture were natural polymers rubber and gutta-percha, the cable was wrapped around with steel wire armor, and in coastal areas the armor was sometimes made two-layer to protect against anchors and fishing gear.

The possibility of instantaneous data transmission over thousands of kilometers is now taken for granted - for one and a half hundred years no one is surprised. But behind the obviousness are rather big technological tricks. The World Wide Web is not only bandwidth and length, but also mass and volume. To be convinced of this, it is enough to look at the drum in which the rolled cable is stored. The dimensions of this “coil” are quite consistent with the scale of the tasks being solved. A modern cable drum on a specialized vessel is thousands of tons and cubic meters plus special systems for cable laying and unwinding. And there are three or four such drums on the flagships of the “wire fleet”. The design should ensure winding, unwinding and storage of the cable without kinks, heavy loads and other extreme sports. It is with this that the large diameter of the “coil” is connected - modern underwater wires are not designed for any serious bending, therefore it is impossible to roll the coil too tightly - it will break.

Today's fiber optic cables have multiple layers of protection against corrosive seawater and mechanical damage. A bundle of transmitting fibers "floats" in a hydrophobic gel filler inside a copper or aluminum tube covered with a layer of flexible polycarbonate and an aluminum screen. The next layer is twisted steel wire wrapped with mylar tape. Outside, the cable is dressed in a polyethylene "shirt". Another option is a cable with a profiled carrier core. In such a scheme, up to eight optical pairs are placed inside each of the six gel-filled channels extruded in a polyethylene cord. Pairs are protected by wound Mylar tape, a copper shield and a thick polyethylene braid. A thick steel wire is laid in the center of the cord to make the cable rigid. Warranty for submarine communication cables is at least 25 years.

Where is the internet coming from

The first attempt to use an underwater cable to transmit a signal - not yet a telegraph one - was made in Russia in 1812 by P. Schilling to detonate sea mines equipped with an electric fuse from the shore.
The first attempt to lay a telegraph cable under water was made in 1839 in India. The East Indian Telegraph Company laid a cable along the bottom of the Hooghly River, near Calcutta. Unfortunately, data on the use of the line have not reached us.
The first transatlantic cable, laid between in 1858, lasted only about a month. The cables of 1865-66 served without repair for about five years, and a number of sections of the cable of 1873 (Ireland - Newfoundland) - for about ninety years.
By 1900, 1750 underwater telegraph lines with a total length of about 300 thousand kilometers had been laid in the world. The first telephone line across the Atlantic was laid in 1956.
The longest submarine power cable is laid along the bottom of the North Sea between Eemshaven (Netherlands) and Feda (Norway). The NorNed line is 580 km long and is designed for 700 MW. Operation began in May 2008.
The length of the Unity line, which in 2010 connected Japan (the city of Chikura) with the US west coast (Los Angeles) along the bottom of the Pacific Ocean, is 10 thousand km, the throughput is 7.68 Tbps.

High-voltage lines connecting islands, oil platforms and wind farms with the mainland are even better protected than communications ones. The conductors are usually three copper strands, each shielded with semiconductor tape and a thick layer of XLPE insulator. Another screen is laid over the insulator, and a waterproof tape is wound. Outside, each conductive core is covered with a sealed lead sheath and anti-corrosion polyethylene braid. If ethylene propylene rubber (EPR) is used as the main insulator, the lead layer is often omitted in order to facilitate the construction. A modern power cable must include at least one fiber optic pair for data transmission. Conductors and optical fiber are filled with polypropylene or polyethylene, covered with an amplifier tape, polymer braid, steel wire armor and another layer of polyethylene yarn with a thickness of at least 4 mm. As a rule, such cables serve faithfully for decades. The rapid development of offshore wind power and oil and gas production has led to the fact that at present all the eight submarine power cable factories on the planet are operating at their capacity limit. And the demand for their products is only growing.

Italian cable layer Gliulio Verne

A matter of technology

So, the global demand for traffic is just crazy - according to the Telegeography agency, since 2007 it has been growing by 100% per year. Underwater power lines are proliferating along with alternative energy. We have a great cable. It remains only to connect them islands and continents.

Creation of an underwater cable system— the most complicated operation performed by top-class professionals in extreme conditions with surgical precision. First of all, it is revealed optimal route. With the help of special vessels equipped with side-scan sonar, remote-controlled submersibles and acoustic Doppler profilers, oceanographers examine the areas of the bottom, which will soon lay the thread. The altitude profile of the route, the composition of the bottom soil, the seismic activity of the zone, the presence and nature of currents, natural and artificial obstacles in the laying corridor are carefully recorded and analyzed. Based on the data obtained, a line configuration and a laying flow chart are compiled. Beacons equipped with GPS transmitters and radio beacons are placed at critical points of the route. Only after that, cable-laying ships come into play.

With a displacement of 10,557 tons, Cable Innovator is the world's largest ship built for laying optical cable. Built in 1995 at the Finnish shipyards Kvaerner Masa, owned by Global Marine Systems. Three 17-meter drums can hold 2333 tons of cable each. For 60 days, a ship with a crew of eight dozen people can operate in full autonomy, unwinding the cable line at speeds up to 6.6 knots (slightly more than 12 km/h).

There are no serious differences between cable ships for laying power and communication lines. The difference is only in the specific equipment. In addition, "siloviki" usually work in coastal areas, and optics are pulled for thousands of kilometers in the open sea. The world's largest and most productive high-voltage vessels are the Norwegian paver Skagerrak, owned by Nexans, and the Giulio Verne of the Italian corporation Prysmian Group. Cable Innovator from the Global Marine Systems flotilla with a displacement of 10,557 tons has no equal among the “signalers” - it can take on board 8,500 km of optical cable. The largest fleets of cable ships are based in the Pacific Ocean - eight ships work for the American company SubCom and the same number for its Japanese competitor NEC. The characteristic features of cable layers are a small working draft, not exceeding 10 m, mandatory equipment with dynamic positioning and hydroacoustic orientation systems, as well as extremely sensitive propulsion units that allow speed control with pharmaceutical precision. A modern cable-laying machine is equipped with a multi-pulley cable winch machine that develops traction up to 50 tons and lowers the cable into the water at a speed of about 1.5 km/h. In addition, there are cranes for diving and lifting submersibles, splicing and cutting devices, diving equipment and much more.

Schematic map of the first transatlantic cable laid along the seabed in the summer of 1858. Due to the imperfection of the design, poor insulation and the use of too high voltage for transmission, the communication line then worked for only about a month, and the quality and, accordingly, the speed of communication were all the time below any criticism. On September 1, 1858, the last message was transmitted across the Atlantic, after which the continents were again separated. By 1861, about 20 thousand kilometers of submarine cable had been laid in various parts of the world, but no more than a quarter of them were in working order. America and Europe were finally connected by telegraph on July 27, 1866, after which communication was never interrupted for more than a few hours.

The rent of such a miracle of technology is about $ 100,000 per day, however, demand exceeds supply. SubCom's Tyco Resolute, for example, with cylindrical sheds that can hold 2,500 km of fiber optic cable, is operational for years to come. The same can be said about the Skagerrak. Yes, and the rest are not sitting idle: fishing tackle, ship anchors, landslides and earthquakes that damage underwater highways keep a squadron of cable ships in constant combat readiness. Cases of cable breakage due to shark bites and even theft of tens of kilometers of power lines by pirates have been recorded. Only in the Atlantic, up to 50 repair operations are performed per year. But it's a matter of technique...

To the bottom

Laying of any cable begins with land. This jewelry operation is usually carried out by a team of experienced divers. The cable layer comes closer to the shore, gets up at a given course and bleeds the required section of the "thread" into the water, connected to an exhaust cable, previously wound from the shore through a long pipe dug into the ground. During this operation, the etched cable hangs on floats to avoid critical kinks and tangles. The process of bringing the cable and cable to the junction box is monitored visually by means of television cameras - it will be much more difficult to repair this line segment later than any other. Checking the integrity of the cable by applying a signal (or voltage, if it is power) occurs during laying in a constant mode. If everything is in order, the pipe is walled up from the sea side, water is pumped out of it, and instead of it, an anti-corrosion mixture of inhibitors, biocides that kill water bacteria, and a deoxidizer that absorbs oxygen is fed inside. Shore laying, despite its apparent simplicity, is the longest stage of work. It took the team of Bjorn Ladegaard, an engineer at Nexans, three whole weeks to hook up a power line on the beaches of Majorca in January of this year in a section of only about 500 m!

In the open sea, everything is easier, but even there there are difficulties. The relief of the seabed is rarely comfortable enough for the so-called free laying, when the "thread" is lowered directly to the ground. So, the power line between Spain and the Balearic Islands had to be buried in a section of 283 km, including at depths of more than a kilometer. Another 23 km were carved into the rock!

In the underwater wilds, indispensable assistants to engineers - deep-sea submersibles with remote control via a hose cable. Nexans specialists have three machines at their disposal. Small and nimble CapTrack with a set of sensors, a GPS transmitter, powerful searchlights and TV cameras is designed for operational monitoring and accurate laying of the "thread" on the bottom. In areas with extremely difficult terrain, an underwater bulldozer Spider is used with additional “weapons” in the form of a drilling head, water cannons and a powerful pump. Spider's manipulator arm can be equipped with a whole bunch of creepy tools designed to destroy. Most of the work on the routes is done by the Capjet trench machine with its water jet plow. The exposed soil is constantly pumped out of the one and a half meter trench and fed behind the stern of the Capjet, filling up the laid cable.

When there are more serious obstacles in the way of the laying, engineers use arched transition systems. The cable in a special sleeve is suspended on anchored hermetic steel cylinders filled with air. In the presence of "associated" pipelines, the cable is fixed to them with special clips. If you have to “step over” the pipes, concrete bridges or protective sleeves are used, which are placed in right place underwater vehicles. In areas with stable bottom currents, the cable, like any cylindrical body, is subjected to the destructive effect of vortex vibrations. Gradually, these high-frequency vibrations, imperceptible to the eye, destroy even reinforced concrete beams. To combat this trouble, the “thread” is dressed in a plastic spiral “plumage”. Soft polyurethane mats or tape protectors are used to prevent the insulation from chafing against rocky ground. All operations for lengthening, branching the cable, installing amplifiers and control equipment on it are carried out on the ship immediately before laying this section on the bottom. At the finish of the route, the cable layer repeats the operation to bring the line ashore. After that, the line is tested and put into operation.

Isn't it easier to launch a couple of satellites into orbit, you ask? Not easier. The speeds are not the same - megabits per second are no longer suitable for the 21st century. Yes, and gigabit - too. Underwater terabites are a completely different matter ...