VSWR Meter dB scale Vs. SWR Scale

Discussion in 'Wireless & RF Design' started by vinodquilon, Jun 11, 2011.

  1. vinodquilon

    Thread Starter Member

    Dec 24, 2009
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    In the figure shown below, SWR Meter is using in two different
    scenarios. First one for SWR measurement and second one for
    dB measurement.

    In SWR meter, same needle rolls on two scales simultaneously.
    There is no any front panel controls to switch between dB and
    SWR scales.

    Then how can I confirm the first setup is for SWR and second
    is for dB ?

    In short, my doubt is that-Whether it indicates input VSWR or
    feeding power of Horn antenna in the first case on SWR Meter ?


    [​IMG]
     
  2. t_n_k

    AAC Fanatic!

    Mar 6, 2009
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    The question isn't all that clear to me. There are also a few unknowns here.

    1. The attenuator & detector are probably well matched??
    2. The horn antenna may or may not be well matched??
    3. What adjustments are being made during the test - frequency sweep? Attenuation level? Slotted line location for the detector? .... ????

    If the observation was only about what occurs as the slotted line location for the detector is changed then depending on the load (horn antenna) match quality one may observe signal level fluctuations along the line in the presence of any standing waves.

    Also if you actually want the SWR rather than just signal dB, don't you have to make another connection to the indicating instrument? One normally uses a directional coupler for such purposes. What's the indicating instrument?

    Your question needs some further clarification.
     
    Last edited: Jun 11, 2011
  3. vinodquilon

    Thread Starter Member

    Dec 24, 2009
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    0

    Indicating Instrument is SWR Meter.
     
  4. bertus

    Administrator

    Apr 5, 2008
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  5. t_n_k

    AAC Fanatic!

    Mar 6, 2009
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    You are being rather coy about this.

    Perhaps I didn't ask the questions clearly enough.

    I was thinking more along the lines of make and model. Is your question one with a practical purpose? If you are using an instrument with which you are unfamiliar, then more often than not you would refer to the operating manual to determine the function and use of the instrument.
     
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