Transmission Line Question

Thread Starter

crazyengineer

Joined Dec 29, 2010
156
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?
 

steveb

Joined Jul 3, 2008
2,436
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?
Do you mean, why don't we use fiber optic cables always in place of RF cables?
 

MrChips

Joined Oct 2, 2009
22,107
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.
 

crutschow

Joined Mar 14, 2008
25,677
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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