[time-nuts] 75Z vs 50Z for GPS receivers

Brooke Clarke brooke at pacific.net
Mon Jan 29 17:21:18 EST 2007


Hi Hal:

The corner frequency is mainly becuase of the capactance at low 
frequencies.  A transmission line at audio frequency looks like a shunt 
capacitor and the inductance no longer is working aginst it, so you 
don't get a real Zo but instaed capactance.  Loss really does not come 
into it.
In the RG-58 plot at:  
http://www.pacificsites.com/~brooke/Zo.shtml#RG58  the resistance is 
only 1.4 Ohms and is not a factor.

Have Fun,

Brooke

w/Java http://www.PRC68.com
w/o Java http://www.pacificsites.com/~brooke/PRC68COM.shtml
http://www.precisionclock.com



Hal Murray wrote:

>>acc. my understanding, the characteristic impedance of a transmission
>>line (ideally losseless) is constant and waveform independant,
>>    
>>
>
>The catch is we are discussing the non-lossless case.
>
>The corner frequency is where the losses become significant.
>
>I think there is another corner where the skin effect on the center conductor 
>kicks in.
>
>
>  
>


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