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A History of Radio Technology

Demystifying Telecommunications

By: Al Klase

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What do these Have in Common?

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Information-Age Timeline

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A Favorite Quote

“Any sufficiently advanced technology is indistinguishable from magic.” Arthur C. Clark, "Profiles of The Future", 1961 (Clarke's third law)English physicist & science fiction author (1917 – 2008) Inventor of the communications-satellite concept.

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A Mysterious Force• Start at the beginning• In the Stone Age

– Sticks– Stones– Animal Parts

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Amber

• Naturally polymerized tree resin• Greeks called it elektron

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Electrostatic Experiments

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Electric Field

Johann Carl Friederich Gauss

1777-1855

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The Condenser or Capacitor

C = Q / V

Q = charge in Coulombs(6.241506×1018 electrons/C )

V = EMF in Volts

Stores Energy as electrostatic charge.

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Luigi Galvani (1737-1798)

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Alessandro Volta (1745-1827)

Ca. 1774

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Circuits and Schematics

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Yet Another Mysterious Force• Heavy black rock• Lodestone• Proved to be iron ore• Greeks found theirs in Magnesia

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The Compass

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Magnetic Field due to Electrical Current

1820 - Hans Christian Ørsted

André-Marie Ampère (1775-1836)

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Electro Magnet and Inductor

Joseph Henry1797 - 1878

Ca. 1824

Taught and did research at Princeton.

Stores energy as a magnetic field.

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Samuel Morse’sTelegraph

1838(Binary Serial Communications!)

Speedwell

Morristown.

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Maxwell

James Clerk Maxwell1831 - 1879

Treatise on Electricity and Magnetism(1873)

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More Maxwell

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i

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Alternating Current

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Oscillation and Resonance

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High-frequency AC Oscillator

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Eureka!

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HertzCa. 1888

Heinrich Hertz1857 - 1894

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The First Radio Receiver

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A Hertzian Experiment

From Invention & Innovationin the Radio Industry,W. Rupert MacLaurin, 1949

29PHz = petahertzEhz = exahertz

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+ Satellite TV+ WiFi, BluetoothCellphones +

+ Satellite TVGPS +

Short-Wave

Broadcast

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Propagation Modes Direct-Wave

All Frequencies

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Propagation Modes Ground-Wave

ELF-VLF-LF-MF

Below 30 HZ – 3 MHz

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Propagation Modes Sky-Wave

MF-HF (VHF) - 300 KHz – 30+ MHz

• Can allow global point-to-point communications and broadcasting

• Varies with:

Frequency

Time of day

Season

Solar activity (11-year Cycle)

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PART2

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Guglielmo Marconi•Born 1874•Wealthy Italian father•Wealthy Irish mother (Jamison)•Tech. Institute at Leghorn included telegraphy•Inspired by Hertz’s Obituary in 1894

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Marconiat Villa Grifone

Photos and drawings from Early Radio by Peter R. Jensen

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Marconi Developments

•1896 Moves to Great Britain•Sept. 1896, 2.8Km, Salisbury Plain•Mar. ‘97, 14Km, Bristol Channel•Late 1898, 29Km, Isle of Wright

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Marconi 1896

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Patent 7777Application filed 12 April 1900

From The Wonders of Wireless TelegraphyJ. A. Fleming, London, 1913

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Passive Receivers

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The Fleming Valve

           

       John Ambrose

Fleming3

(1849 - 1945)

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We need areliable

Amplifier!

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From The Wonders of Wireless TelegraphyJ. A. Fleming, London, 1913

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The Audion

Lee Deforest

1906

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An Audion Radio Receiver

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Armstrong

Edwin Howard Armstrong

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The Regenerative Circuit

“Great amplificationobtained at once!”

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Regen PrototypeDemonstrated to Sarnoff at the Marconi station at Belmar

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Radiotelephone

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The Birth of Broadcasting

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Timeline

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VLF = Very Low Frequency

10 Km

30 KHz3 KHz

100 Km

FREQUENCY

WAVELENGTH

20 KHz

Audio 20Hz – 20KHz

Submarine Communications

NTSC Horizontal Osc.15.734 KHz

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LF = Low Frequency

1000 m

300 KHz30 KHz

10 Km

FREQUENCY

WAVELENGTH

200 KHz

Long-Wave Broadcast 148.5 to 283.5 KHz

Aircraft Beacons

“Atomic” Clocks 60KHz

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MF = Medium Frequency

1000 m

3 MHz300 KHz

10 Km

FREQUENCY

WAVELENGTH

2 MHz

“Standard” AM Broadcast 540 to 1700 KHz

Aircraft Beacons

1000 KHz

160 MHam

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HF = High Frequency

1000 m

30MHz3 MHz

10 Km

FREQUENCY

WAVELENGTH

20MHz

Short-wave Broadcast

10 MHz

Ham

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VHF = Very High Frequency

1000 m

300 MHz30 MHz

10 Km

FREQUENCY

WAVELENGTH

200 MHz

TV2-6

100 MHz

Ham

TV7-13

FM Broadcast

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UHF = Ultra-High Frequency

1000 m

3 GHZ300 MHz

10 Km

FREQUENCY

WAVELENGTH

2 GHz

UHF TV

1000 MHz

Keyless Entry 315 MHz

Analog Cell Phone

WiFi etc. 2.4 GHz

Digital Cellphone

GPS 1.575 GHz

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UHF = Ultra-High Frequency

1000 m

3 GHz300 MHz

10 Km

FREQUENCY

WAVELENGTH

2 GHz1 GHz

Ham

TV14-92

FM Broadcast

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Repeating Hertz’s Experiments

Transmitter Receiver

MatchingTransformer

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Transmission

TransmitterReceiver

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Reflection

Transmitter Receiver

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Standing Waves

Transmitter Receiver

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Standing Waves

http://en.wikipedia.org/wiki/Standing_wave

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Calculations (lambda) (Wavelength) = C (Speed of Light) / Frequency

FC

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