Strange output matching on RF amp

Discussion in 'Wireless & RF Design' started by Synaps3, May 11, 2016.

  1. Synaps3

    Thread Starter Member

    Jun 5, 2013
    67
    2
    So I received a high power RF amplifier from a guy who repaired it for me. Long story short, the guy said he also did some "tuning" to give more output at my desired frequency. Anyway, when I received the amp, it just had what looked like an inductor soldered on the output, but the other end was not connected to anything. The "inductor" was made from coax with both ground and center RF wire connected, but nothing connected on the other end. Can anyone explain to me what this is or if the guy is pranking me to see if I would notice?
     
  2. bertus

    Administrator

    Apr 5, 2008
    15,635
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    Hello,

    Can you post a picture or a schematic?
    I have seen quite some RF circuits with coax coils in the end stage.

    Bertus
     
  3. Synaps3

    Thread Starter Member

    Jun 5, 2013
    67
    2
    No, I don't have a picture of the actual amp, but this picture is pretty close to it.
    Now imagine this with an extra loop of brown coax on the end that is only connected on one end. The output is still connected directly on the board. This shouldn't do anything, right?
    [​IMG]
     
  4. Papabravo

    Expert

    Feb 24, 2006
    10,135
    1,786
    An open stub will have certain characteristics that may or may not help. I hope he measured the actual performance instead of guessing.
     
  5. bertus

    Administrator

    Apr 5, 2008
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