RF cables

Discussion in 'Wireless & RF Design' started by kubeek, Oct 26, 2008.

  1. kubeek

    Thread Starter AAC Fanatic!

    Sep 20, 2005
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    Hi,

    can anyone tell me approximately on what frequency does for example a 50ohm coaxial cable start to act as if it has some impedance, and stops behaving like two pieces of wire?

    Also I am not exactly sure how would I measure the impedance, if I had a signal generator?
     
  2. bertus

    Administrator

    Apr 5, 2008
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  3. beenthere

    Retired Moderator

    Apr 20, 2004
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    If you are transferring power, there really isn't a lower limit. A 50 ohm transmission line is resonant with any frequency applied. It just makes a low loss path between resonant structures.

    That 50 ohm characteristic is always there as long as it is transmitting power.

    You measure indirectly, by comparing the power in your RF output stage and the power developed in a dummy load. Any difference is what got lost in the transmission line and connectors.
     
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