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Thread: SWR meter - Do it yourself project

  1. #1131
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    Sydney Australia
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    Martin's comment that the rectifier diode response is non-linear for RF voltages less than the diode turn-on threshold ( often referred to as the "knee" in the diode turn-on response curve.) This is the reason that DC bias is used to help overcome the diode turn-on response for RF voltage below the knee.

    As you can see from your Vr measurements with the DMM the diode rectified DCV is very low mV below the diode response knee. For a schottky diode the knee is around 250mV. Vr is usually less than this for VSWR <1.5.

    You should be happy with your build for 5.8GHz. It is not that easy to get a VSWR meter with DIY detector to work accurately at this mw frequency.

  2. #1132
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    May 2015
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    Trust me. I am very happy with my swr meter and it was a great learning experience.

  3. #1133
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    Oct 2014
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    Hello is there a lost to buy al the stuuf you need from ebay, to make the swr meter for 5,8Ghz.
    I meand the next products:

    Coupler
    Dummyloads
    Etc

  4. #1134
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    Mar 2015
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    I'm also having hard time finding a directional coupler for 5.8GHz. Any tips where to find one?

  5. #1135
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    Jan 2015
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    Pittsburgh,Pa
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    I found mine on Ebay.have you searched yet? They usually have a couple at a reasonable price point.
    Good luck

  6. #1136
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    Mar 2015
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    Yes I browsed through eBay couple of times. Best one I could find is this
    http://m.ebay.com/itm/Narda-4014C-10...-/231647318458. At $60 it's pretty steep for a component in a meter that I might not be able to get working reliably. Oh well, need to keep looking, I really want to make one

  7. #1137
    Hey guys!

    Another unit here for a reasonable price!

    http://www.ebay.com/itm/Narda-4014C-...item35ef4191ba

    EDIT: Opps you beat me! Sorry!

    Here's another for the cheap it is rated for 5.2GHz max but it would work no problem...
    http://www.ebay.com/itm/NEW-MaCom-2-...-/291001069121

    Martin
    Last edited by Martinba77; 11th August 2015 at 06:56 AM.
    Learning by doing...

  8. #1138
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    Mar 2015
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    Thanks Martin, unfortunate that seller doesn't ship to Europe.

    It seems that all the couplers in the world are in USA

    Would this work: http://m.ebay.com/itm/MAC-Technology...-/131553113285? 5.8 is quite close to 6 GHz.
    Last edited by lauka; 11th August 2015 at 11:09 AM.

  9. #1139
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    Aug 2011
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    15
    A lot are sold on Ebay from Israel.

  10. #1140
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    Aug 2015
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    2

    Swr

    Hi

    i got this one http://www.bmisurplus.com/uploads/pr...ages/18249.jpg. But I not understand why we need to add a diode resistor and capacitor for measuring a swr?
    thanks

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