On the History of Wireless

Transcription

1 e On the History of Wireless 600 BC f Richard A. Formato, PhD, W3AZ Life Senior Member, IEEE: rf2@ieee.org 2015 Chatham Marconi Maritime Center. All rights reserved worldwide

2 WIRELESS TIMELINE First Battery (Allesandro Volta) Galvani-Volta Debate (~20 yrs) The Industrial Revolution Lightning = Electricity (Ben Franklin) Electricity coined (William Gilbert) Static Electricity & Magnetism B.C. A.D. Induction (Faraday) Electrodynamics (Andre Ampere) E&M Theory (Maxwell) Electric waves produced/detected Marconi Creates the Wireless Industry 2

3 WIRELESS TIMELINE: SOME KEY EVENTS c600 B.C.: Thales of Miletus discovers static electricity & magnetism (lodestone) 1600: Gilbert coins term electricity 1752: Franklin proves that lightning is a form of electricity 1780: Galvani studies electricity in frog's legs 1800: Volta develops the first battery ( Pile ) 1820: Oersted discovers magnetic fields can be caused by electricity 1826: Ampère publishes a theory of electrodynamics 1827: Ohm publishes a mathematical theory of electricity 1831: Faraday demonstrates electromagnetic induction 1867: Gauss Law Published (formulated 1835) 1870s: Thomas Edison builds a DC electric generator 1873: Maxwell publishes A Treatise on Electricity and Magnetism 1880s: Nikola Tesla developed an AC motor 1888: Hertz produces & detects radio waves 1892: Lorentz publishes the theory of the electron (discovered 1896). 1897: Marconi radios 20 miles (Isle of Wight to Poole) The competition: 1858, Transatlantic undersea telegraph cable 3

4 Communication Before Wireless - 1 Smoke Signals Drums Carrrier Pigeons Delivery (e.g. Pony Express) Semaphores (still used) 4

5 Communication Before Wireless - 2 BPL Leventhal CC from Bill Burns Undersea Cables in

6 ELECTRICITY S GROWTH SPURT - 1 Stephen Gray ( ) - Sent 150 m on wet hemp, even further on metal - Identified different types of conductors - Discovered the earth to be an electric reservoir Gray s first experiment with different conductors Ben Franklin ( ) - Only one electric fluid, but two types: Positive and Negative - Famous kite experiment: Lightning is atmospheric electricity (1752) - Boy suspended by (insulating) silk cords could be charged and then as a (conducting) body could (electrostatically) attract small objects (pub in a German book on Gray s work) 8

7 ELECTRICITY S GROWTH SPURT - 2 Pieter van Musschenbroek ( ) - The Leyden jar (1746) - Stored electric charge - Finally, portable electricity - Today s Capacitor - 18 th century craze: shocking chains of people! (Abbe Nollet zapped 600 monks in a circle) Electricity could be carried around in a jar! Charles-Augustin de Coulomb ( ) - Torsion balance (1785) - 1 st precise statement on electric force - Coulomb s Law (1785) r 9

8 VOLTA S BATTERY: FINALLY, PORTABLE DC ELECTRICITY Volta invited by the French Academy of Sciences to demonstrate the Pile to Napoleon (Paris, 1801). Napoleon bestowed on him the title Count. Dissimilar metals 10p: Ni-plated steel 2p: 97% Cu Lemon juice electrolyte 11

9 ELECTRICITY & HEALTH, CURRENT & MAGNETISM John Wesley ( ) - Co-founder Methodist Church - The Desideratum, or Electricity Made Plain and Useful by a Lover of Mankind and of Common Sense (1760) - Electric shock treatment of mental disorders - Genesis of widespread therapeutic use of electricity - Two views: good health requires electric balance illness caused by obstructed electric fluid flow Hans Christian Ørsted ( ) - Discovery: Electric current creates magnetism - Famous compass needle experiment (1820) - Demonstrated circular magnetic field surrounding straight current-carrying wire Der Geist in der Natur (1854) The Spirit in Nature (Ørsted) 12

10 Four Pieces to the EM Puzzle 1. Gauss Law Electric & Magnetic Flux 2. Ampere s Law Steady-state Current & Magnetic Field 3. Faraday s Law of Induction Varying Magnetic Field Electric Field 4. Maxwell s Displacement Current Varying Electric Field Magnetic Field 13

11 James C. Maxwell ( ) 1 Age 18, two papers at the Royal Society of Edinburgh - On the Equilibrium of Elastic Solids; Rolling Curves Age 24, presented On the Transformation of Surfaces by Bending (1854) Age 29, published On the stability of the motion of Saturn's rings (1859) showing rings composed of individual particles (verified by spacecraft Voyager flybys in the 1980s!) Published the seminal paper in Control Theory, On Governors On reciprocal figures, frames and diagrams of forces (1870) [rigidity of lattices] Textbooks Theory of Heat (1871) and Matter and Motion (1876) Introduced statistical analysis in physics Maxwell-Boltzmann Distribution (kinetic theory of gases) Introduced Dimensional Analysis in physics (1871) Developed the Color Triangle (four parameters: hue, intensity, brightness, tint) Published On the Theory of Colour Vision; developed first durable color photograph. On the anniversary of Maxwell s 100 th birthday, Einstein said his work was the most profound and the most fruitful that physics has experienced since the time of Newton. 18

12 James C. Maxwell Quintessential theoretician (Faraday experimented in a lab, Maxwell in his head) - Used mechanical analogies and imagined being inside the machine ( Gedankenexperiment ) - Philosophically a world apart from Michael Faraday - One of the world s most influential scientists LAST PIECE On Physical Lines of Force (1861) A Dynamical Theory of the Electromagnetic Field (1865) in which he wrote The agreement of the results seems to show that light and magnetism are affections of the same substance, and that light is an electromagnetic disturbance propagated through the field according to electromagnetic laws. The complete EM theory in a seminal book: A Treatise on Electricity and Magnetism (1873) relationships: electric/magnetic fields, electric charge, electric current introduced a radical new idea, Displacement Current Electromagnetic Waves 19

13 2 1 E 2 E 2 2 c t EM WAVE EQUATIONS Combine Maxwell Eqs. Electromagnetic Waves B 2 B 2 2 c t In free space the wave propagates at a constant speed c 1 0 the Speed of Light, x 10 8 meters/sec (186, miles/sec)

14 AT LAST EM WAVES IN THE LAB! Heinrich Hertz ( ) - Series of experiments Credited with creating and receiving EM waves - 1m Cu wires with 30cm Zn spheres ~100 MHz - Christmas Eve 1887: Hertz realized that he had produced and received an electromagnetic wave It s of no use whatsoever just an experiment that proves Maestro Maxwell was right. We just have these mysterious electromagnetic waves that we cannot see with the naked eye. But they are there. 22

15 Hmmm USELESS? NOT QUITE EVERY PORTION OF THE EM SPECTRUM IS USED IN TODAY S TECHNOLOGY! Scientific American Magazine 23

16 From The Long Road to Maxwell s Equations, James C. Rautio, IEEE Spectrum Magazine, Dec

17 MARCONI CREATES THE WIRELESS INDUSTRY - 1 Guglielmo Marconi ( ) - Son of Giuseppe Marconi and Annie Jameson Marconi - Mother was daughter of Andrew Jameson, owner Jameson Irish Whiskey Distillery - Annie & Giuseppe eloped because her family objected, but over time Annie regained good relations which was important in Marconi s commercial success - Guglielmo was mostly home schooled (Annie was Protestant and uncomfortable with Italy s Catholic school system) - Marconi was enthralled by stories about Michael Faraday and Ben Franklin (books in the family library) - Age 13, constructed a Lightning Detector (1887) Wireless lab aboard Yacht Elettra,

18 MARCONI CREATES THE WIRELESS INDUSTRY Tutored in experimental physics by Prof. Vincenzo Rosa - Annie arranged visit to Professor Augusto Righi (University of Bologna) who appointed Guglielmo as lab assistant (age 17) - Righi s article on Hertz s experiments cemented Marconi s interest in wireless - Marconi made many improvements to Righi s spark apparatus and became an accomplished experimentalist (i.e., engineer ) - Age 20, built wireless telegraph system using his own design for the spark gap transmitter/receiver and adding a Morse Code key/printer - Reproduced Franklin s Kite Experiment which later influenced his development of much better wireless antennas - Discovered that increased antenna height improved range outdoors and that grounded vertical antennas worked best 27

19 The COHERER Detector Branly Effect: metal filing-filled tube exhibits very high resistance (MΩ) due to surface oxidation. External disturbance resistance drops to only a few ohms. Mechanical shock restores the initial high resistance. Popov s Coherer Lightning Detector, mid-1890 s? Branly s Experiment Nov (IEEE History of Communications, Sept. 2009) Marconi s range: mid-1895, 1600m mid-1896, 2400m [with TX/RX gnd ] Marconi s 1896 Receiver Marconi s Improved Coherer 28

20 MARCONI CREATES THE WIRELESS INDUSTRY Marconi methodically extended his communication range At first, room-to-adjacent-room in the family home Earliest outdoor tests in 1895 over 100 s of meters using his new antenna Family physician and parish priest so impressed they together with Marconi s parents composed a letter to the Italian Ministry of Posts The response was encouragement for maritime use but nothing more, whereupon Marconi turned to England: (i) the world s dominant maritime power; (ii) Annie s influential family connections might help Guglielmo and Annie set off to England in February, 1896 Marconi and his apparatus in England, Marconi s genius lay as much, if not more so, in his business acumen as in his talent and tenacity as an engineer After consultation with Italy s ambassador, Marconi filed his first patent application in England, March 19, 1896 (issued as British patent 12,039, July 2, 1897) 29

21 MARCONI CREATES THE WIRELESS INDUSTRY - 4 WIRELESS DEMONSTRATIONS cemented Marconi s hegemony in the fledging field: 1896: Fall, Signaled > one mile at Salisbury Plain 1897: May, Signaled across the Bristol Channel (Wales) 1897: November, First permanent wireless telegraph station installed at the Royal Needles Hotel, Isle of Wight 1898: July, Live coverage, Kingstown Regatta sailboat race (demonstrated beyond-the-horizon & over hills links) 1899: March 27, First wireless link across the English Channel 1899: October, Radioed results of the International Ocean Yacht Races offshore Sandy Hook, NJ, to the New York Herald Tribune Founded the Wireless Telegraph and Signal Company, July, 1897 (renamed Marconi Wireless Telegraph Co. Ltd. in 1900) 30

22 MARCONI CONQUERS THE ATLANTIC! 12 December TX: Poldhu, Cornwall, UK RX: St. Johns, Newfoundland, CA S (3 Morse dots) Launching the Levitor Poldhu, England Marconi at Signal Hill RX Station The 600 ft Kite Antenna 31

23 LOTS OF TALENT & EFFORT AND SOME LUCK Marconi unknowingly benefited from radio effects that were not understood at the time. An example: First attempt to signal across the Bristol Channel the antenna was placed high on a cliff overlooking the ocean. Two days of attempts failed to establish a 3.3 mile link from Lavernock Point to Flat Holm Island. But, as soon as Marconi placed the antenna/transmitter on the shore, he completed the link! Early links Groundwave propagation Luckily Marconi was steered toward maritime applications where groundwave works best GW propagation not fully understood until Norton (1936) GW = Surface Wave + Space Wave (= Direct + Reflected rays) Vertical antennas best (recall Kite Experiment) Seawater path much, much better than over land paths 32

24 Mother Nature Smiles on Marconi? 12 December TX: Poldu, Cornwall, UK RX: St. Johns, Newfoundland, CA Excerpt, IEEE Conference Paper, st transocean link Skywave? Actual propagation mode unknown even today Probable ionospheric HF (3-30 MHz) plus GW If skywave, then diurnally & seasonally variable 33

25 Poldhu HF Radiation Patterns? σ=0.002 S/m, ε r =10 (dry, sandy soil) MHz 12.5 MHz 34

26 THE NOBEL PRIZE IN PHYSICS Guglielmo Marconi Karl Ferdinand Braun Awarded 1909 Nobel Prize in Physics "in recognition of their contributions to the development of wireless telegraphy." 35

27 TODAY S WIRELESS TECHNOLOGY Any sufficiently advanced technology is indistinguishable from magic. - Arthur C. Clarke IEEE Spectrum Magazine A single transistor c1950 s 2008: 400 Million transistors in one chip!! Intel Corp. Penryn (45nm) 2014: 1300 Million transistors/chip!!! Intel Corp. Core M (14nm) 36

28 Around the Corner? A completely interconnected wireless world? Est. 7 trillion machines ~2020! The M2M Ecosystem Axeda Corp. (2011) There will be no limit on the number of connections as part of the mobile grid. Everything has the potential to be connected Call it the 100 percent ceiling. Ivan Seidenberg, CEO Verizon, 2009 Adapted from: M2M Evolution Conference, Austin, TX, September,

29 The Internet of Things IoT: Objects, animals, people have unique ID s and transfer data over a network with no human-human or human-machine interaction. Key elements: WWW infrastructure and WIRELESS/MEMS technologies. IoT: Micro Wireless Pru Antenna Farm: Macro Wireless Some Day! Soon??? Wearable Tech WPT Smart cars/smart roads "It s difficult to make predictions, especially about the future. - Mark Twain 38

30 A PLUG FOR AMATEUR RADIO Primary Amatuer Radio Bands Amateur radio, or Ham radio, is a hobby enjoyed by about 3 million people throughout the world. Common Ham bands. Photo shows a ham shack in Kansas. Courtesy Virginia Diodes, Inc. (VDI) 39