Marconi: Between Earth & Air

AM & Broadcast

Hermeet Gill

Amplitude Modulation II - Hermeet Gill

Amplitude Modulation II - Hermeet Gill

"Hello. One, two, three, four. Is it snowing where you are?"

"Hello. One, two, three, four. Is it snowing where you are?"

"Hello. One, two, three, four. Is it snowing where you are?"
"Hello. One, two, three, four. Is it snowing where you are?"

"Hello. One, two, three, four. Is it snowing where you are?" Music from the collections of Sydney Living Museums / Historic Houses Trust of NSW

"Hello. One, two, three, four. Is it snowing where you are?"

"Hello. One, two, three, four. Is it snowing where you are?"

"Hello. One, two, three, four. Is it snowing where you are?"
"Hello. One, two, three, four. Is it snowing where you are?"

"Hello. One, two, three, four. Is it snowing where you are?" Music from the collections of Sydney Living Museums / Historic Houses Trust of NSW

The new technology which allowed sound to be transmitted by radio waves was amplitude modulation (AM), developed by Reginald Fessenden in 1900.

Hands-free

During World War I, radio communication was widely used. But pilots — who needed both hands to control their aircraft — struggled to operate Morse keys.

So planes were fitted with the new wireless technology.

Spotter pilots still received messages in Morse code, but now they could reply using their voice — a hands-free way to report enemy positions.

Amplitude Modulation I - Hermeet Gill

Hello one, two, three, four. Is it snowing where you are, Mr Thiersen?

The first experimental sound broadcast by Reginald Fessenden, 1900: "Hello. One, two, three, four. Is it snowing where you are, Mr Thiessen?"

Amplitude Modulation I - Hermeet Gill

Hello one, two, three, four. Is it snowing where you are, Mr Thiersen?

The first experimental sound broadcast by Reginald Fessenden, 1900: "Hello. One, two, three, four. Is it snowing where you are, Mr Thiessen?"

After the war, there was a huge surge of interest in amateur radio. Many people had worked with radio, and been trained how to use the technology.

Enthusiasts could make their own crystal radio sets, and gradually manufacturers — including the Marconi Company — made them available in the consumer market.

The Marconi Company started daily 30-minute radio transmissions to help enthusiasts calibrate their radio equipment.

At first, these were readings from railway timetables or daily newspapers.

Later — as the transmissions became increasingly popular — they included gramophone recordings, and even live singers.

This became the basis of radio broadcast.

The BBC

Marconi’s Wireless Telegraph Company — along with other manufacturers — formed the British Broadcasting Company Ltd in 1922.

In 1927, it became the British Broadcasting Corporation — the BBC. 

A licence for a radio receiver granted by the BBC — then part of the British Post Office — on 3 November 1922

A licence for a radio receiver granted by the BBC — then part of the British Post Office — on 3 November 1922

A licence for a radio receiver granted by the BBC — then part of the British Post Office — on 3 November 1922

As radio became more popular, the Daily Mail persuaded the Marconi Company to broadcast the first advertised live performance by a professional singer.​

On 15 June 1920, world-famous opera singer Dame Nellie Melba performed a song called Home Sweet Home.

Transmitted from Marconi's site in Chelmsford, Essex, the signals were heard as far away as Iran and Newfoundland. 

​This is the microphone Dame Nellie used for that famous broadcast. ​

'Melba' Telephone Microphone No C100L
Marconi Company · English · 1920
Inventory № 54651

The microphone is improvised from a device designed for telephones and a cone made from the wood of cigar boxes. 

When sound enters the cone, it vibrates a membrane which presses against a chamber of carbon granules, changing their electrical resistance. 

This produces an electrical signal, which a transmitter then converts into a radio signal.

Music from the collections of Sydney Living Museums / Historic Houses Trust of NSW

Music from the collections of Sydney Living Museums / Historic Houses Trust of NSW

Marconiphone Universal Baby Crystal Receiver
Marconiphone Company · English · c.1924
Inventory № 58056

The Baby Crystal Receiver was an entry-level radio produced by the Marconi Company under the Marconiphone brand.

It cost the equivalent of around £100 in modern money.

The Baby Crystal Receiver was a very simple device that didn’t need a power supply.

It gathered energy from radio waves, so had to be connected to a good aerial.

Crystal Radios are named after the crystals used in their circuits. The silvery-grey crystal in this radio is galena.

This radio is missing its "cat's whisker", a fine wire suspended from a holder — it looks like a drumstick here — over the crystal.

The “cat’s whisker” touches the crystal and is very gently wiggled using the handle at the top until it creates a good connection.

Galena is a semiconductor, which allows current to flow in one direction from the “cat’s whisker” but not in the other — like a modern diode. 

This allows the radio signal to be converted into sound.

By law, all commercially available radios had to have a BBC logo to show they were approved for use.

Music from the collections of Sydney Living Museums / Historic Houses Trust of NSW

Music from the collections of Sydney Living Museums / Historic Houses Trust of NSW

Music from the collections of Sydney Living Museums / Historic Houses Trust of NSW

Music from the collections of Sydney Living Museums / Historic Houses Trust of NSW
'Concerning the Marconiphone', the instruction book for the V2 valve radio, The Bodleian Libraries, University of Oxford

'Concerning the Marconiphone', the instruction book for the V2 valve radio, The Bodleian Libraries, University of Oxford

'Concerning the Marconiphone', the instruction book for the V2 valve radio, The Bodleian Libraries, University of Oxford

'Concerning the Marconiphone', the instruction book for the V2 valve radio, The Bodleian Libraries, University of Oxford

'Concerning the Marconiphone', the instruction book for the V2 valve radio, The Bodleian Libraries, University of Oxford

'Concerning the Marconiphone', the instruction book for the V2 valve radio, The Bodleian Libraries, University of Oxford

'Concerning the Marconiphone', the instruction book for the V2 valve radio, The Bodleian Libraries, University of Oxford

'Concerning the Marconiphone', the instruction book for the V2 valve radio, The Bodleian Libraries, University of Oxford

Marconiphone Two-Valve Receiver Type V2
Marconi Company · London · 1923
Inventory № 15836

In 1922, The Marconi Company started producing the Marconiphone V2.

It cost the equivalent of nearly £1,200 in modern money — fortunately, you could also buy one on hire-purchase. 

Up to two pairs of headphones connected directly to the receiver.

You could also add a speaker by connecting an additional amplifier, which allowed people to listen together. 

For the first time, it was possible to keep up to date with live news broadcasts, and listen to live music without leaving home.

Music from the collections of Sydney Living Museums / Historic Houses Trust of NSW

A Circuit Diagram for the Domestic V2A Radio, The Bodleian Libraries, University of Oxford

Music from the collections of Sydney Living Museums / Historic Houses Trust of NSW

Music from the collections of Sydney Living Museums / Historic Houses Trust of NSW

Music from the collections of Sydney Living Museums / Historic Houses Trust of NSW

A Circuit Diagram for the Domestic V2A Radio, The Bodleian Libraries, University of Oxford

Music from the collections of Sydney Living Museums / Historic Houses Trust of NSW

Music from the collections of Sydney Living Museums / Historic Houses Trust of NSW
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