Transmission Line Question

Discussion in 'General Electronics Chat' started by crazyengineer, Dec 27, 2011.

  1. crazyengineer

    Thread Starter Member

    Dec 29, 2010
    156
    2
    So I was reading about transmission lines, and I do not understand why we still use them, even though power can be lost if the line is too long and the frequency of the source is to high? Can anyone explain to me why we still use transmission lines for most applications?
     
  2. steveb

    Senior Member

    Jul 3, 2008
    2,433
    469
    Do you mean, why don't we use fiber optic cables always in place of RF cables?
     
  3. wmodavis

    Well-Known Member

    Oct 23, 2010
    737
    150
    To transfer power efficiently from one location to another such as from a television transmitter to the antenna.
     
    jaygatsby likes this.
  4. MrChips

    Moderator

    Oct 2, 2009
    12,449
    3,365
    It is not a question of why do we still use transmission lines.
    It is a fact of life and Maxwell's equations that the wire between the transmitter and the load (antenna) behaves the way that it does.
     
  5. crutschow

    Expert

    Mar 14, 2008
    13,053
    3,244
    Any line is a transmission line and you can't avoid them if you use conductors for signal transmission. Whether its transmission characteristics are important depends upon the application (signal frequency components and line length being the primary considerations). To transmit high frequency signals with minimum distortion and maximum power the transmission line must be matched to the load and source. Otherwise you get signal reflections which manifests as standing waves in RF and distortion of pulses in digital transmission.
     
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