1.1 Introduction1.2 Vacuum Tube Development1.2.1 Pioneer Developers1.2.1.1 Radio Central1.2.1.2 WLW: The Nation's Station1.2.1.3 UHF: A New Technical Challenge1.2.1.4 Birth of the Klystron1.2.1.5 Nuclear Magnetic Resonance1.2.2 Transistor Is Born1.2.3 Satellite Technology1.2.4 Standardization1.2.5 Transmission Systems1.3 Vacuum Tube Applications1.3.1 Market Overview1.4 Electromagnetic Radiation Spectrum1.4.1 Low Frequency: 30–300 kHz1.4.2 Medium Frequency: 300 kHz–3 MHz1.4.3 High Frequency: 3–30 MHz1.4.4 Very High Frequency: 30–300 MHz1.4.5 Ultrahigh Frequency: 300 MHz–3 GHz1.4.6 Superhigh Frequency: 3–30 GHz