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1
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, Bluetooth
Cellphones +
+ 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 Prototype
Demonstrated 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
F
C
FC
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