A report on Guglielmo Marconi

Marconi's first transmitter incorporating a monopole antenna. It consisted of an elevated copper sheet (top) connected to a Righi spark gap (left) powered by an induction coil (center) with a telegraph key (right) to switch it on and off to spell out text messages in Morse code.
British Post Office engineers inspect Marconi's radio equipment during a demonstration on Flat Holm Island, 13 May 1897. The transmitter is at centre, the coherer receiver below it, and the pole supporting the wire antenna is visible at top.
Plaque on the outside of the BT Centre commemorates Marconi's first public transmission of wireless signals.
SS Ponce entering New York Harbor 1899, by Milton J. Burns
Marconi watching associates raising the kite (a "Levitor" by B.F.S. Baden-Powell ) used to lift the antenna at St. John's, Newfoundland, December 1901
Magnetic detector by Marconi used during the experimental campaign aboard a ship in summer 1902, exhibited at the Museo Nazionale Scienza e Tecnologia Leonardo da Vinci of Milan.
Marconi demonstrating apparatus he used in his first long-distance radio transmissions in the 1890s. The transmitter is at right, the receiver with paper tape recorder at left.
Marconi caricatured by Leslie Ward for Vanity Fair, 1905
Villa Marconi, with Marconi's tomb in foreground.
American electrical engineer Alfred Norton Goldsmith and Marconi on 26 June 1922.
Guglielmo and Beatrice Marconi c. 1910
Memorial plaque in the Basilica Santa Croce, Florence. Italy
Guglielmo Marconi Memorial in Washington, D.C.
Bronze statue of Guglielmo Marconi, sculpted by Saleppichi Giancarlo erected 1975 Philadelphia, Pennsylvania
Italian lira banknote, 1990 issue

Italian inventor and electrical engineer, known for his creation of a practical radio wave-based wireless telegraph system.

- Guglielmo Marconi

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Marconi Company

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British telecommunications and engineering company that did business under that name from 1963 to 1987.

British telecommunications and engineering company that did business under that name from 1963 to 1987.

An employee of the Marconi Company, England, 1906
Marconi Wireless Station in Somerset, New Jersey, in 1921.
Marconi advertisement from the 26 October 1923 issue of The Radio Times, threatening prosecution for infringements of Marconi patents.
New Street Factory in 2018

Its roots were in the Wireless Telegraph & Signal Company founded by Italian inventor Guglielmo Marconi in 1897, which underwent several changes in name after mergers and acquisitions.

A US Army Signal Corps radio operator in 1943 in New Guinea transmitting by radiotelegraphy

Wireless telegraphy

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Transmission of telegraph signals by radio waves.

Transmission of telegraph signals by radio waves.

A US Army Signal Corps radio operator in 1943 in New Guinea transmitting by radiotelegraphy
Amateur radio operator transmitting Morse code
Tesla's explanation in the 1919 issue of "Electrical Experimenter" on how he thought his wireless system would work
Thomas Edison's 1891 patent for a ship-to-shore wireless telegraph that used electrostatic induction
Example of transatlantic radiotelegraph message recorded on paper tape at RCA's New York receiving center in 1920. The translation of the Morse code is given below the tape.
In World War I balloons were used as a quick way to raise wire antennas for military field radiotelegraph stations. Balloons at Tempelhofer Field, Germany, 1908.
Guglielmo Marconi, the father of radio-based wireless telegraphy, in 1901, with one of his first wireless transmitters (right) and receivers (left)
German troops erecting a wireless field telegraph station during World War I
German officers and troops manning a wireless field telegraph station during World War I
Mobile radio station in German South West Africa, using a hydrogen balloon to lift the antenna

The first practical radio transmitters and receivers invented in 1894–1895 by Guglielmo Marconi used radiotelegraphy.

Low-power inductively coupled spark-gap transmitter on display in Electric Museum, Frastanz, Austria. The spark gap is inside the box with the transparent cover at top center.

Spark-gap transmitter

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Obsolete type of radio transmitter which generates radio waves by means of an electric spark.

Obsolete type of radio transmitter which generates radio waves by means of an electric spark.

Low-power inductively coupled spark-gap transmitter on display in Electric Museum, Frastanz, Austria. The spark gap is inside the box with the transparent cover at top center.
Pictorial diagram of a simple spark-gap transmitter from a 1917 boy's hobby book, showing examples of the early electronic components used. It is typical of the low-power transmitters homebuilt by thousands of amateurs during this period to explore the exciting new technology of radio.
Hertz's first oscillator: a pair of one meter copper wires with a 7.5 mm spark gap between them, ending in 30 cm zinc spheres. When 20,000 volt pulses from an induction coil (not shown) was applied, it produced waves at a frequency of roughly 50 MHz.
Circuit of Hertz's spark oscillator and receiver
Circuit of Marconi's monopole transmitter and all other transmitters prior to 1897.
Transmitter (bottom) and receiver (top) of the first "syntonic" radio system, from Lodge's 1897 patent
Inductively coupled spark transmitter. C2 is not an actual capacitor but represents the capacitance between the antenna A and ground.
Circuit of Poldhu transmitter. Fleming's curious dual spark gap design was not used in subsequent transmitters.
Telefunken 100 kW transoceanic quenched spark transmitter at Nauen Transmitter Station, Nauen, Germany was the most powerful radio transmitter in the world when it was built in 1911
Heinrich Hertz discovering radio waves with his spark oscillator (at rear)
Hertz's drawing of one of his spark oscillators. (A,A') antenna, (J) induction coil
Hertzian spark oscillator, 1902. Visible are antenna consisting of 2 wires ending in metal plates (E), spark gap (D), induction coil (A), auto battery (B), and telegraph key (C).
Hertz's 450 MHz transmitter; a 26 cm dipole with spark gap at focus of a sheet metal parabolic reflector
Jagadish Chandra Bose in 1894 was the first person to produce millimeter waves; his spark oscillator (in box, right) generated 60 GHz (5 mm) waves using 3 mm metal ball resonators.
Microwave spark oscillator demonstrated by Oliver Lodge in 1894. Its 5-inch resonator ball produced waves of around 12 cm or 2.5 GHz
Demonstration inductively coupled spark transmitter 1909, with parts labeled
Amateur inductively coupled spark transmitter and receiver, 1910. The spark gap is in glass bulb (center right) next to tuning coil, on top of box containing glass plate capacitor
Standard Marconi inductively coupled transmitter on ship 1902. Spark gap is in front of induction coil, lower right. The spiral oscillation transformer is in the wooden box on the wall above the Leyden jars.
Telefunken 25 kW long distance transmitter built 1906 at Nauen Transmitter Station, Nauen, Germany, showing large 360 Leyden jar 400 μF capacitor bank (rear) and vertical spark gaps (right)
Tesla's inductively coupled power transmitter (left) patented 2 September 1897
Braun's inductively coupled transmitter patented 3 November 1899
Stone's inductively coupled transmitter (left) and receiver (right) patented 8 February 1900
Marconi's inductively coupled transmitter patented 26 April 1900.
Ship radio room with 1.5 kW Telefunken quenched-spark transmitter
Tuned circuit of transmitter. (top) quenched gap, (center) oscillation transformer, Leyden jars
Quenched spark gap from transmitter, left. The handle turns a screw which puts pressure on the stack of cylindrical electrodes, allowing the gap widths to be adjusted.
Cross section of portion of quenched spark gap, consisting of metal disks (F) separated by thin insulating mica washers (M) to make multiple microscopic spark gaps (S) in series
A powerful quenched-spark transmitter in Australia. The 6 cylinders in front of the Leyden jars are the quenched spark gaps.
A typical rotary spark gap used in low-power transmitters
Small rotary spark transmitter, 1918
1 kilowatt rotary spark transmitter, 1914.
Fessenden's 35 kW synchronous rotary spark transmitter, built 1905 at Brant Rock, Massachusetts, with which he achieved the first 2 way transatlantic communication in 1906 on 88 kHz.
US Navy 100 kW rotary gap transmitter built by Fessenden in 1913 at Arlington, Virginia. It transmitted on 113 kHz to Europe, and broadcast the US's first radio time signal.

The first practical spark gap transmitters and receivers for radiotelegraphy communication were developed by Guglielmo Marconi around 1896.

Metal filings coherer designed by Guglielmo Marconi.

Coherer

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Primitive form of radio signal detector used in the first radio receivers during the wireless telegraphy era at the beginning of the 20th century.

Primitive form of radio signal detector used in the first radio receivers during the wireless telegraphy era at the beginning of the 20th century.

Metal filings coherer designed by Guglielmo Marconi.
Branly's electrical circuit tube filled with iron filings (later called a "coherer")
Marconi's 1896 coherer receiver, at the Oxford Museum of the History of Science, UK. The coherer is on right, with the decoherer mechanism behind it. The relay is in the cylindrical metal container (center) to shield the coherer from the RF noise from its contacts.
The circuit of a coherer receiver, that recorded the received code on a Morse paper tape recorder.
A radio receiver circuit using a coherer detector (C). The "tapper" (decoherer) is not shown.
A coherer with electromagnet-operated "tapper" (decoherer), built by early radio researcher Emile Guarini around 1904.

That same year, Italian inventor Guglielmo Marconi demonstrated a wireless telegraphy system using Hertzian waves (radio), based on a coherer.

A variety of radio antennas on Sandia Peak near Albuquerque, New Mexico, US

Radio

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Technology of signaling and communicating using radio waves.

Technology of signaling and communicating using radio waves.

A variety of radio antennas on Sandia Peak near Albuquerque, New Mexico, US
Radio communication. Information such as sound is converted by a transducer such as a microphone to an electrical signal, which modulates a radio wave produced by the transmitter. A receiver intercepts the radio wave and extracts the information-bearing modulation signal, which is converted back to a human usable form with another transducer such as a loudspeaker.
Comparison of AM and FM modulated radio waves
Frequency spectrum of a typical modulated AM or FM radio signal. It consists of a component C at the carrier wave frequency f_c with the information (modulation) contained in two narrow bands of frequencies called sidebands (SB) just above and below the carrier frequency.
Satellite television dish on a residence
Satellite phones, showing the large antennas needed to communicate with the satellite
Firefighter using walkie-talkie
VHF marine radio on a ship
Parabolic antennas of microwave relay links on tower in Australia
RFID tag from a DVD
Satellite Communications Center Dubna in Russia
Communications satellite belonging to Azerbaijan
Military air traffic controller on US Navy aircraft carrier monitors aircraft on radar screen
ASR-8 airport surveillance radar antenna. It rotates once every 4.8 seconds. The rectangular antenna on top is the secondary radar.
Rotating marine radar antenna on a ship
A personal navigation assistant GPS receiver in a car, which can give driving directions to a destination.
EPIRB emergency locator beacon on a ship
Wildlife officer tracking radio-tagged mountain lion
US Air Force MQ-1 Predator drone flown remotely by a pilot on the ground
Remote keyless entry fob for a car
Quadcopter, a popular remote-controlled toy
Television receiver

In the mid 1890s, building on techniques physicists were using to study electromagnetic waves, Guglielmo Marconi developed the first apparatus for long-distance radio communication, sending a wireless Morse Code message to a source over a kilometer away in 1895, and the first transatlantic signal on December 12, 1901.

The factory building in 2011

New Street Works

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Manufacturing plant built for the Marconi Company in Chelmsford, England in 1912.

Manufacturing plant built for the Marconi Company in Chelmsford, England in 1912.

The factory building in 2011
New Street Factory entrance with the blue plaque in 2018

Guglielmo Marconi had established his company offices at the former silk-works on Hall Street, Chelmsford in 1898.

UHF half-wave dipole

Dipole antenna

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Simplest and most widely used class of antenna.

Simplest and most widely used class of antenna.

UHF half-wave dipole
Dipole antenna used by the radar altimeter in an airplane
Animated diagram of a half-wave dipole antenna receiving a radio wave. The antenna consists of two metal rods connected to a receiver R. The electric field ( E, green arrows ) of the incoming wave pushes the electrons in the rods back and forth, charging the ends alternately positive  (+)  and negative  (−) .  Since the length of the antenna is one half the wavelength of the wave, the oscillating field induces standing waves of voltage ( V, represented by red band ) and current in the rods. The oscillating currents (black arrows) flow down the transmission line and through the receiver (represented by the resistance R).
Cage dipole antennas in the Ukrainian UTR-2 radio telescope. The 8 m by 1.8 m diameter galvanized steel wire dipoles have a bandwidth of 8–33 MHz.
Real (black) and imaginary (blue) parts of the dipole feedpoint impedance versus total length in wavelengths, assuming a conductor diameter of 0.001 wavelengths
Feedpoint impedance of (near-) half-wave dipoles versus electrical length in wavelengths. Black: radiation resistance; blue: reactance for 4 different values of conductor diameter
Length reduction factor for a half-wave dipole to achieve electrical resonance (purely resistive feedpoint impedance). Calculated using the Induced EMF method, an approximation that breaks down at larger conductor diameters (dashed portion of graph).
"Rabbit-ears" VHF television antenna (the small loop is a separate UHF antenna).
Collinear folded dipole array
A reflective array antenna for radar consisting of numerous dipoles fed in-phase (thus realizing a broadside array) in front of a large reflector (horizontal wires) to make it uni-directional.

On the other hand, Guglielmo Marconi empirically found that he could just ground the transmitter (or one side of a transmission line, if used) dispensing with one half of the antenna, thus realizing the vertical or monopole antenna.

Animation of a half-wave dipole antenna radiating radio waves, showing the electric field lines. The antenna in the center is two vertical metal rods connected to a radio transmitter (not shown). The transmitter applies an alternating electric current to the rods, which charges them alternately positive (+) and negative (−). Loops of electric field leave the antenna and travel away at the speed of light; these are the radio waves. In this animation the action is shown slowed down enormously.

Radio wave

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Radio waves are a type of electromagnetic radiation with the longest wavelengths in the electromagnetic spectrum, typically with frequencies of 300 gigahertz (GHz) and below.

Radio waves are a type of electromagnetic radiation with the longest wavelengths in the electromagnetic spectrum, typically with frequencies of 300 gigahertz (GHz) and below.

Animation of a half-wave dipole antenna radiating radio waves, showing the electric field lines. The antenna in the center is two vertical metal rods connected to a radio transmitter (not shown). The transmitter applies an alternating electric current to the rods, which charges them alternately positive (+) and negative (−). Loops of electric field leave the antenna and travel away at the speed of light; these are the radio waves. In this animation the action is shown slowed down enormously.
Diagram of the electric fields (E) and magnetic fields (H) of radio waves emitted by a monopole radio transmitting antenna (small dark vertical line in the center). The E and H fields are perpendicular, as implied by the phase diagram in the lower right.
Animated diagram of a half-wave dipole antenna receiving a radio wave. The antenna consists of two metal rods connected to a receiver R. The electric field ( E, green arrows ) of the incoming wave pushes the electrons in the rods back and forth, charging the ends alternately positive (+) and negative (−) . Since the length of the antenna is one half the wavelength of the wave, the oscillating field induces standing waves of voltage ( V, represented by red band ) and current in the rods. The oscillating currents (black arrows) flow down the transmission line and through the receiver (represented by the resistance R).

Italian inventor Guglielmo Marconi developed the first practical radio transmitters and receivers around 1894–1895.

Electrical engineering

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Engineering discipline concerned with the study, design, and application of equipment, devices, and systems which use electricity, electronics, and electromagnetism.

Engineering discipline concerned with the study, design, and application of equipment, devices, and systems which use electricity, electronics, and electromagnetism.

The discoveries of Michael Faraday formed the foundation of electric motor technology.
Guglielmo Marconi, known for his pioneering work on long-distance radio transmission
A replica of the first working transistor, a point-contact transistor
Metal–oxide–semiconductor field-effect transistor (MOSFET), the basic building block of modern electronics
The top of a power pole
Satellite dishes are a crucial component in the analysis of satellite information.
Control systems play a critical role in spaceflight.
Electronic components
Microprocessor
A Bayer filter on a CCD requires signal processing to get a red, green, and blue value at each pixel.
Flight instruments provide pilots with the tools to control aircraft analytically.
Supercomputers are used in fields as diverse as computational biology and geographic information systems.
The Bird VIP Infant ventilator
Oscilloscope
An example circuit diagram, which is useful in circuit design and troubleshooting.
Belgian electrical engineers inspecting the rotor of a 40,000 kilowatt turbine of the General Electric Company in New York City
The IEEE corporate office is on the 17th floor of 3 Park Avenue in New York City
Satellite communications is typical of what electrical engineers work on.
The Shadow robot hand system
A laser bouncing down an acrylic rod, illustrating the total internal reflection of light in a multi-mode optical fiber.
Radome at the Misawa Air Base Misawa Security Operations Center, Misawa, Japan

In 1895, Guglielmo Marconi began work on a way to adapt the known methods of transmitting and detecting these "Hertzian waves" into a purpose built commercial wireless telegraphic system.

Édouard Branly

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French inventor, physicist and professor at the Institut Catholique de Paris.

French inventor, physicist and professor at the Institut Catholique de Paris.

Branly's coherer
Original Branly tube (no. 78) for radiodetection
Plaque at the Musée Édouard Branly on rue d'Assas in Paris

It was further developed by Guglielmo Marconi, then replaced about 1907 by crystal detectors.