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