AVS 56th International Symposium & Exhibition
    History Session: Centennials of Wireless Broadcasting Monday Sessions
       Session HI-MoM

Invited Paper HI-MoM5
Mutual Evolution of Vacuum and Broadcasting Technology

Monday, November 9, 2009, 9:40 am, Room B2

Session: History Session: Centennials of Wireless Broadcasting
Presenter: S. Rutherford, Duniway Stockroom Corp.
Correspondent: Click to Email
Since the earliest days of radio tubes/valves, there has been a mutually beneficial evolution of radio and vacuum technologies. Whether broadcasting or transmission, receiving or amplification types of tubes; whether vacuum tubes or semiconductor circuits - vacuum production, processing, measurement and maintenance have all profited from the evolution of radio technology. The ‘discovery’ of vacuum involved observations of the operation of a mercury barometer. Early vacuum pumps refined the mercury-piston approach, but then relatively rapid evolution of both compression mechanism and sealant/medium took place. In later years, the introduction of a variety of traps and capture pumps, starting with flash getters and leading to getter-ion pumps, greatly improved the cleanliness of the vacuum tube environment. Pressure measurement likewise evolved from the barometric model to include thermal gauges, based on observations of thermal effects in vacuum tubes; ionization gauges based directly on the triode radio tube; and cold cathode gauges related to magnetron and ion pump technologies This rich history of mutually improving development of vacuum and radio technology has also resulted in enhancing the application of vacuum technology to many other new and expanding applications. In fact, some of these new applications have led to the continuously advancing replacement of vacuum tubes!