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The origins of radio

Radio pioneers

The following personalities were pioneers in radio communications:

Heinrich Hertz, Guglielmo Marconi, Alexander Popov and William Preece

Maxwell, James Clerk

Discovering radio waves (1864) : an amazing piece of maths

The story of radio began almost 30 years before Marconi with a Cambridge professor called James Clerk Maxwell. Though he had never seen or experienced radio waves, Maxwell successfully forecast most of the laws that govern their propagation, calculating their speed and noting their resemblance to light waves.

Maxwell showed how radio waves could be reflected, absorbed and focused like the beam from a torch - and could change the very nature of the object on which they were focused.

Hardly anybody believed Maxwell in 1864; however, the theories were later quantified by Oliver Heaviside into two equations, and in 1879, Prof. David Hughes walked up Portland Place with a device that caught the sound of radio waves.

In 1887, German scientist Heinrich Hertz carried out a famous set of experiments that proved Maxwell had been right all along - and in 1894, the British scientist Oliver Lodge succeeded in transmitting wireless signals over 150 yards. 

Early coherer radio receiver - a Connected Earth aretefact, now in the Museum of London

Wireless and radio : when is 'wireless' called 'radio'?

Wireless is the generic term for any transmission that is made without using wires between points, although it frequently is used to describe radio it also covers photophone, induction and broken wire systems.

Radio is the term used first in the USA, derived from radiation - the principle that governs radio waves.

It's a characteristic of all electromagnetic waves that both the electric signal and the magnetic field that accompanies it cycle many times a second. Think of a cork on a pond - as waves pass it, it goes up and down.

The frequency of the wave is simply the number of times per second the cork goes up and down as the peaks and troughs of the wave pass it. Electromagnetic waves cycle a lot faster than this, and are measured in Hertz, where 1Hz is one cycle per second.

The wavelength is the distance between each consecutive peak or trough, so if you multiply the wavelength by the frequency, you get the speed of the wave. A 100Hz wave with a wavelength of 1 metre travels at 100 metres per second.

Radio waves travel in straight lines, so theoretically no radio station should be able to transmit much farther than 40 miles because of the Earth's curvature. This is the case for television and cellphone transmissions in the UHF waveband, although a natural effect of the earth's atmosphere allows lower radio frequencies (or longer wavelengths) to bounce back and travel around the world.

Marconi Lizard wireless station

Marconi's first wireless signal (1893) : three dots that made history

In June 1896 a 22-year-old Italian physicist called Guglielmo Marconi, who had settled in London the previous year, called upon the Engineer-in-Chief of the Post Office to demonstrate his new system of 'telegraphy without wires'. He had already approached the Italian government - but it showed no interest.

The Post Office was more receptive and allowed Marconi to set up his transmitter on the roof of the Central Telegraph Office, and a receiver on the roof of a building called 'GPO South' in Carter Lane, 300 yards away.

On July 27 Marconi succeeded in sending the signals between the two locations. It was the world's first recorded wireless message. The following month The Post Office gave Marconi backing to experiment with wireless apparatus on Salisbury Plain and in coastal locations.

Interior of Lizard wireless station - a National Trust property. The inker (centre) is a Connected Earth artefact

The first transatlantic radio message (1901) : Cornwall to St John's

Following the successes of his British and Italian experiments at home, Marconi became obsessed with the idea of sending messages across the Atlantic. He built a transmitter, 100 times more powerful than any previous station, at Poldhu, on the southwest tip of Cornwall and in November 1901 installed a receiving station at St. John's, Newfoundland. On December 12, 1901, he received signals from across the ocean - three dots representing the letter 'S' heard out of the background static.

The achievement has long been controversial - in theory, medium wave radio signals cannot carry that far during the day. But it is possible that Marconi may unknowingly also have been transmitting on the short waves as well.

Whatever the truth of it, news of Marconi's reported feat spread rapidly around the world, and he was acclaimed by outstanding scientists, including Thomas A. Edison. From now on, telegraphy and telephony would no longer be reliant on cables to cross oceans, or span continents.

Map of Marconi's links from the Isle of Wight

Alum Bay, Isle of Wight (1897) : Marconi's first wireless station

Guglielmo Marconi revolutionised communications with his radio system and he made most of his early experiments at Alum Bay, Isle of Wight. Alum Bay was a deserted and beautiful stretch of coastline that provided open water straight to the mainland just as far as his equipment's top range.

Marconi established his first radio station in sight of the famous 'Needles', where he managed to transmit to two hired ferryboats and another station in Bournemouth.

Then, in August 1898, Marconi was invited by Queen Victoria to demonstrate his equipment aboard the Royal Yacht. During his presentation he amazed his audience by contacting the royal home at Osborne House and the Alum Bay station.

Alum Bay may have helped launch wireless but this didn't impress the inventor's landlord, the Royal Needles Hotel, which raised his rent. Marconi's dismantled the station at the end of May 1900 and moved further down the coast and instead Alum Bay was destined to be stormed by day-trippers every summer.

Marconi station at Poldhu, c1900

Poldhu, Cornwall (1901) : bringing the world together

Poldhu was the spot chosen by Marconi to make the first transatlantic wireless transmission, because it stood directly opposite Cap Cod, where its sister radio station was being built.

He bought the land in 1900, and construction work began immediately. It was a massive project, which dwarfed anything he had built before. Around 400 wires were suspended in an inverted cone shape from twenty 200ft high masts.

Infuriatingly the system was blown down during a storm, so a temporary aerial was hastily set up, using two surviving masts, to let the transatlantic experiments carry on. The system was replaced with four wooden towers by the time the first 'official' transmission was made between King Edward VII and President Roosevelt.

The station came under government control in the First World War and closed in 1933. A small museum stands on the site now.

Plaque commemorating Cape Cod Marconi Station

Cape Cod Marconi station (1903) : an ocean view

At the turn of the century Marconi searched for a wireless station on the east coast of America to tackle his next big project - communicating across the Atlantic. He needed somewhere with a clear view right across the ocean and found Cape Cod.

Cape Cod was a desolate headland with a raised plateau looking out over the ocean. In March 1901 he discovered the perfect spot at South Wellfleet, a favourite site for holidaymakers. On the other side of the Atlantic he established its opposite station at Poldhu in Cornwall, not far from Goonhilly.

Disaster almost struck when a poorly built aerial collapsed in a gale, but it was rebuilt in time for Wellfleet to play host to U.S. President Theodore Roosevelt, to make the world's first official two-way 'trans-ocean' communication with King Edward VII at Poldhu on January 18, 1903.

Wellfleet continued as a wireless station until it was closed for safety reasons in 1917.

fun and games

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what's on

The UK's first permanent gallery dedicated to the history of information and communication technologies opens in the new Information Age gallery at London’s Science Museum.

audio history

Take a trip down memory lane with extracts of the interviews which have been recorded as part of the Connected Earth oral history programme.

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