Calibration Lab in Philadelphia

Discussion in 'Radio Circuits, Repair & Performance' started by OA4AJP, Jul 20, 2019.

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  1. OA4AJP

    OA4AJP Ham Member QRZ Page

    Dear All,

    I will travel the first week of August 2019 to Philadelphia and I have a new Mini circuits Power Meter PWR-4GHS.

    I would like to know the uncertainty/accuracy values of my Power Meter comparing it against with a more accurate calibrated power meter like an HP437B.

    Do you know some Calibration Lab or Amateur Radio Club in Philadelphia which can help me to calibrate my equipment. If I have to pay for the service I would.

    Alfredo Mendiola
  2. K3XR

    K3XR Ham Member QRZ Page

  3. KX4Z

    KX4Z Ham Member QRZ Page

    You understand the max rating on that device is way less than a watt, right?
  4. G0HZU

    G0HZU QRZ Member

    I've not used the Mini Ccts PWR-4GHS series power meter but I'd recommend you get familiar with its technical limitations before spending money on an expensive calibration check. From what I can see on the datasheet this isn't a classic 'average' reading power meter and it is probably a diode based meter. So it might only operate in square law at the lower end of its power range. So it probably can't cope very well with amplitude modulated signals or harmonic distortion on the test signal when used up in the milliwatt(s) region for example. The input VSWR isn't very impressive beyond about 500MHz so this will introduce a fair bit of uncertainty too.

    If you send it to a calibration lab they will test it under very strictly controlled conditions with a clean cw test source that has harmonics better than -50dBc (typically better than -65dBc) and a very accurate 50R source impedance. Unless you replicate these conditions at home then this info they provide will have limited benefit if you want to know the overall uncertainty of any future measurements you make at home. You really need to study the datasheet of your power meter and understand its limitations because the overall uncertainty could creep up a lot due to mismatch uncertainty or because of harmonics or modulation or any spurious signals.
    Last edited: Jul 21, 2019
  5. OA4AJP

    OA4AJP Ham Member QRZ Page

  6. OA4AJP

    OA4AJP Ham Member QRZ Page

    Ok, thank you for the information.

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