Post on 17-Dec-2015
RadioRadio
*Warning**Warning*Heavy Science Heavy Science Content AheadContent Ahead
Baghdad battery – 250 Baghdad battery – 250 BCEBCE
Electricity was a heavy duty toy for Electricity was a heavy duty toy for decades, including Ben Franklin and his decades, including Ben Franklin and his kite, people rubbing cat skins on glass or kite, people rubbing cat skins on glass or amber rods, spinning sulfur balls, and amber rods, spinning sulfur balls, and sparking everything and everyone in sightsparking everything and everyone in sight
Luigi Galvani - 1786Luigi Galvani - 1786
Believed Believed everything everything contained contained electricityelectricity
Looked for “animal Looked for “animal magnetism”magnetism”
Touched different Touched different metals to frogs’ metals to frogs’ legs which legs which twitchedtwitched
Alessandro Volta - 1796Alessandro Volta - 1796
Alessandro Volta - 1796Alessandro Volta - 1796
Volta took Galvani’s Volta took Galvani’s experiment and showed experiment and showed that it was the current that it was the current produced by the produced by the different metals that different metals that caused the twitchcaused the twitch
Built a pile of Built a pile of alternating sandwiches alternating sandwiches of zinc and copper in an of zinc and copper in an acid and created acid and created electicityelecticity
Hans Christian Oersted - Hans Christian Oersted - 18201820
Oersted’s experiment - Oersted’s experiment - 18201820
In a lecture in Copenhagen he In a lecture in Copenhagen he performed an experiment to performed an experiment to demonstrate there was no demonstrate there was no connection between electricity and connection between electricity and magnetism by showing that an magnetism by showing that an electric current passing through a electric current passing through a wire wouldn’t affect a nearby wire wouldn’t affect a nearby compass needlecompass needle
Imagine his Imagine his surprise when the surprise when the needle swung the needle swung the moment he turned moment he turned on the currenton the current
He demonstrated He demonstrated that electricity that electricity created a magnetic created a magnetic fieldfield
William Sturgeon - 1825William Sturgeon - 1825
Created the first Created the first electromagnet by electromagnet by wrapping wire wrapping wire around a soft iron around a soft iron bar and sending a bar and sending a current through current through the wirethe wire
Electricity can Electricity can create magnetismcreate magnetism
Michael Faraday - 1826Michael Faraday - 1826
Reversed Reversed Sturgeon’s Sturgeon’s experimentexperiment
Showed that Showed that magnetism could magnetism could create an electric create an electric currentcurrent
Samuel F. B. Morse - Samuel F. B. Morse - 18381838
Used a an on-off Used a an on-off switch – the switch – the telegraph key – to telegraph key – to turn an electric turn an electric current on and off, current on and off, sending pulses of sending pulses of current through a current through a wire to an wire to an electromagnet that electromagnet that would click in time would click in time to the pulsesto the pulses
Johannes Mueller - 1840Johannes Mueller - 1840
Examined physical sensationsExamined physical sensations Can you feel colorsCan you feel colors Can you hear shapesCan you hear shapes Can you smell soundsCan you smell sounds
Discovered that each sense detects Discovered that each sense detects different thingsdifferent things
We think this is obvious, but no one We think this is obvious, but no one had had provenproven it before. Remember it before. Remember “common sense”?“common sense”?
Herman Hemholtz - 1857Herman Hemholtz - 1857
Meuller’s pupilMeuller’s pupil Investigated hearingInvestigated hearing Noticed sound produced vibrationsNoticed sound produced vibrations
Did the vibrations operate at Did the vibrations operate at different frequencies?different frequencies? They didThey did Thus, sound traveled at different Thus, sound traveled at different
frequenciesfrequencies Used an electromagnet to attract the Used an electromagnet to attract the
arms of a tuning fork, causing it to arms of a tuning fork, causing it to vibrate and produce soundvibrate and produce sound
Leon Scott de Martinville - Leon Scott de Martinville - phonautograph - 1857phonautograph - 1857
Attached a bristle to a Attached a bristle to a membrane at the end of membrane at the end of a cone, set the bristle to a cone, set the bristle to touch a piece of smoked touch a piece of smoked glassglass
Spoke into the coneSpoke into the cone membrane vibrated to membrane vibrated to
the sound and the the sound and the bristle etched a wavy bristle etched a wavy line onto the smoked line onto the smoked glassglass
The Telephone - 1876The Telephone - 1876
Scott’s membrane, Faraday’s Scott’s membrane, Faraday’s electromagnet, Oersted’s and electromagnet, Oersted’s and Sturgeon’s electromagnet, Morse’s Sturgeon’s electromagnet, Morse’s wire and electrical current, wire and electrical current, Heimholtz’s vibration, Scott’s Heimholtz’s vibration, Scott’s membranemembrane
Bell and GrayBell and Gray
Samuel MorseSamuel Morse
Heinrich Hertz - 1886Heinrich Hertz - 1886
Hemholtz’s pupilHemholtz’s pupil Investigated whether electricity Investigated whether electricity
traveled in frequencies the way traveled in frequencies the way sound didsound did
Spark gap generator
Hertz’ spark gap experiment
Demonstrated that Demonstrated that electricity traveled electricity traveled
through air at specific through air at specific frequencies, just like it frequencies, just like it
did through wiresdid through wires
Guglielmo Marconi - Guglielmo Marconi - 18941894
Marconi radioMarconi radio
Morse keyMorse key
Marconi and his radioMarconi and his radio
Nikola TeslaNikola Tesla
Tesla coil - 1891Tesla coil - 1891
Developed the first Developed the first amplifier coil, the amplifier coil, the Tesla coilTesla coil
Raised the voltage of Raised the voltage of an electrical current an electrical current high enough to allow high enough to allow the air to conduct the air to conduct the currentthe current
Key to wireless Key to wireless transmission of radio transmission of radio waveswaves
Reginald FessendenReginald Fessenden
Felt that the variation in electrical Felt that the variation in electrical amplitude created by a voice, just amplitude created by a voice, just like on a telephone, could be carried like on a telephone, could be carried by electrical wave of a radio signalby electrical wave of a radio signal
Did the first voice broadcast in 1900Did the first voice broadcast in 1900 Short rangeShort range Poor qualityPoor quality
Needed far more powerNeeded far more power
Ernst AlexandersonErnst Alexanderson
Developed the Alexanderson Developed the Alexanderson Alternator, a machine capable of Alternator, a machine capable of generating the power, up to 100,000 generating the power, up to 100,000 hertz, that Fessenden needed to hertz, that Fessenden needed to piggyback voice onto radio wavespiggyback voice onto radio waves
In Dec. 1906, Fessenden did the first In Dec. 1906, Fessenden did the first good voice and music broadcast, going good voice and music broadcast, going hundreds of mileshundreds of miles Poetry and a Bible readingPoetry and a Bible reading A woman singing operaA woman singing opera A violin playing a Christmas carolA violin playing a Christmas carol
Lee de ForestLee de Forest
The audion tube is actually a The audion tube is actually a Fleming valve (British term for tube) Fleming valve (British term for tube) invented in Englandinvented in England
de Forest simply added the bent de Forest simply added the bent wirewire
De Forest’s audion tube - De Forest’s audion tube - 19041904
Audion tube amplified the radio Audion tube amplified the radio signal the way the Alexanderson signal the way the Alexanderson generator increased the electrical generator increased the electrical powerpower
de Forest didn’t know how the de Forest didn’t know how the audion workedaudion worked
Another man didAnother man did
Edwin Howard Edwin Howard ArmstrongArmstrong
Investigated the audion tube, figured Investigated the audion tube, figured out how it worked, and improved itout how it worked, and improved it
Developed “regeneration”Developed “regeneration” The signal was fed back into the tube The signal was fed back into the tube
over and over again, up to 20,000 times over and over again, up to 20,000 times a seconda second
Vastly increased the power of the tube Vastly increased the power of the tube to output the signal – it was an amplifierto output the signal – it was an amplifier
Raise the level enough and the tube Raise the level enough and the tube becomes a transmitterbecomes a transmitter
Armstrong invented the ability to Armstrong invented the ability to broadcast soundbroadcast sound
It combined high frequency waves It combined high frequency waves with low frequency waves, then fed with low frequency waves, then fed them back into the system to amplify them back into the system to amplify the signal and increase its sensitivitythe signal and increase its sensitivity
Resulted in the creation of the home, Resulted in the creation of the home, and the portable, radioand the portable, radio
Armstrong’s Armstrong’s superheterodynesuperheterodyne
Armstrong’s Armstrong’s next next invention invention was the was the superheterodsuperheterodyneyne
Crystal RadioCrystal Radio
David SarnoffDavid Sarnoff
Enamored of radioEnamored of radio Saw the possibilitiesSaw the possibilities Wrote the “Radio Music Box Memo” Wrote the “Radio Music Box Memo”
that outlined the commercial that outlined the commercial possibilities of radiopossibilities of radio
RCA (Radio Corporation of RCA (Radio Corporation of America)America)
After World War IAfter World War I Four companies merged their patents Four companies merged their patents
to create RCAto create RCA American MarconiAmerican Marconi General ElectricGeneral Electric American Telephone & TelegraphAmerican Telephone & Telegraph WestinghouseWestinghouse
Sarnoff named as commercial Sarnoff named as commercial managermanager
Used Armstrong’s inventions, Used Armstrong’s inventions, building superheterodyne radios to building superheterodyne radios to build RCA, the Radio Corporation of build RCA, the Radio Corporation of America, into one of the biggest America, into one of the biggest companies in the worldcompanies in the world
Radio stations soon Radio stations soon opened all over the opened all over the
U.S.U.S.Including KWSC (now KWSU) Including KWSC (now KWSU) in 1922, one of the first radio in 1922, one of the first radio
stations in the countrystations in the country
https://https://skylight.wsu.edu/skylight.wsu.edu/
studentstudent
Examples of Examples of programmingprogramming
OperasOperas ConcertsConcerts SportsSports NewsNews DramasDramas ComediesComedies Variety showsVariety shows Soap operasSoap operas
Pretty much Pretty much everything we get everything we get on TV todayon TV today
Fibber McGee and MollyFibber McGee and Molly
Burns and AllenBurns and Allen
Fred AllenFred Allen
Abbott and CostelloAbbott and Costello
Orson Welles - 1938Orson Welles - 1938
Hindenburg disaster - Hindenburg disaster - 19371937
Edward R. MurrowEdward R. Murrow
The Advent of The Advent of TelevisionTelevision
It was assumed that radio would be deadIt was assumed that radio would be dead Audiences would watch TV instead of Audiences would watch TV instead of
listening to the radiolistening to the radio TV took over so many of the radio programsTV took over so many of the radio programs
Soap operasSoap operas DramasDramas SitcomsSitcoms SportsSports newsnews
Radio had a Radio had a great advantage great advantage
over TV –over TV –PortabilityPortability
Take it anywhereTake it anywhere
Even in the carEven in the car
New kinds of New kinds of programmingprogramming
MusicMusic Top 40Top 40 CountryCountry RockRock Easy listeningEasy listening Golden oldiesGolden oldies
Talk showsTalk shows
Howard SternHoward Stern
On the RightOn the RightRush Limbaugh Michael Savage Rush Limbaugh Michael Savage
Glenn BeckGlenn Beck
On the LeftOn the LeftEd Schultz Stephanie Ed Schultz Stephanie
MillerMiller