Listening to unheard Voices- The Radio
- History
- Demand develops to develop a wireless telegraph
- Useful at sea; no expense of wiring
- [no though of general broadcast]
- Tesla- wants to talk with the Dead, needs refined instrument
- Marconi (1896) patents "wireless"
- Sea Communication to Military Device
- Can the public even use it? (Susan Douglas, historian)
- Material Side
- James C. Maxwell- Electro-magnetism equations worked out (1880s)
- [the Newton of electro-magnetic world?]; Hertz explores frequency
- transmission/propagation of energy in the form of waves-
- same speed
- Modulating Waves-
- Frequency (how long a cycle); Amplitude (how large a cycle)
- Spectrum- the range of waves-
- infrared, radio, visible light, ultraviolet, x-ray, gamma-ray
- continuous- an example of analog
- Photons? What about discrete entities with energy (digital)
- Different ways of approaching the same thing?
- Amplifying- Lee DeForest
- (vacuum tube) 1906 amplifies sound- key device
- provides the way for lower cost receivers and transmitters
- Improved Modulating- Frederick Armstrong (1933)
- Improves amplifying (lawsuits); invents FM to reduce static
- Invents multi-plexing capable of stereo broadcast
- Sets up first FM station- sabotaged by FCC on behalf of RCA
- Driven to suicide by RCA and big business (remember Gutenberg?)
- Digital Radio- (would have to await computer and digital infrastructure)
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