wav file accuracy and stability

If a kiwisdr is connected to a GPSDO, does the wav file in kiwirecorder similarly become more accurate and stable?


  • Jim,

    Just so happens that, with Glenn N6GN, I am looking into this while evaluating FST4W on the HF bands.

    N6GN/K, Glenn's remote KiwiSDR, is connected to a GPSDO and has line of sight path to WWV - it's an ideal test setup. Using kiwirecorder, or the record button, to generate a wav file, having set the frequency to 9999 kHz, USB, and +/-50 Hz bandwidth around 10 MHz, next step is to use the Frequency Analysis function in fldigi to give a csv file of frequency error every second. Attached is a plot from earlier today. Accurate? Yes, to better than 1 milliHz at 10 MHz. Stable? Yes, over the 10 minutes observed less than 1 milliHz. Low jitter? Yes, perhaps +/- 1 or 2 milliHz, but the resolution in fldigi is 1 milliHz.

    Gwyn G3ZIL

  • I have conducted similar tests using my KiwiSdr with the supplied GPS puck. I came up with a method using Argo, when I participated in the ARRL FMT a couple years ago. I got good results and a high ranking in the test. The audio wave files could be replayed to accurately check my measurement calculations.

    The results were still impacted by propagation doppler shift, on both the WWV reference signal, and the FMT transmission. My conclusion is that the only way to accurately measure the frequency is to have a receiver within the ground wave of the transmitter. Also The bigger impact is that I am using the supplied open plastic/metal Kiwi case. Ambient temperature changes will cause the Kiwi to drift. It is put back on frequency with the next gps calibration cycle, but measurements can be incorrect at any time after the calibration. To maintain accuracy the Kiwi must be housed in a temperature controlled, and draft free environment.

    Mike N8OOU

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