jks

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jks
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  • GPS trained Kiwi oscillator accuracy [improvements made in v1.234]

    The Kiwi doesn't implement a PLL. How many time do I have to say this? It's an FLL at best. Even "locked" is too strong a word. "Frequency tracking loop" might be better. A satellite-based crystal calibrator for us old geezers.

    GPS position/timing solutions are noisy by definition. Just go look at the map option of the admin page GPS tab and watch the position solutions wander all over the place. So the question becomes how to best filter this to make ADC clock corrections. You could spend years researching this question. And commercial companies have. The Kiwi, as usual, takes the "best/simple" approach. At (re)start a quick correction based on a limited number of samples to compensate for oscillator temperature offset. Then a switch to a 16-period modified moving average filter with outlier removal. Sounds fancy but it's not ideal.

    Could the software do better than this? Sure. Does it need to? Not clear. Certainly not for casual shortwave listening and even the majority of the extensions (FAX, FSK, CW). TDoA needed to maximize the number of GPS-capable Kiwis. So Christoph has worked on obtaining timing solutions using fewer satellites. And I added Galileo support to increase the number of available satellites. And some Kiwi owners went to considerable trouble to improve their GPS antenna installations (for which we are grateful).

    I was going to rant about the statistical variance of the WSPR database at wsprnet.org but I'll just stop now. I have a dozen new emails waiting for a reply..
    rrobinet
  • CW (morse) decoder extension in KiwiSDR [added in v1.224]

    Okay. Reboot to get v1.228 which should fix it..
    Powernumpty
  • TDoA maps

    Like the first suggestion and I almost implemented the second on this last update.

    I think I need to loosen up the criteria for "GPS is okay" so you don't have as much problem with the third issue. Same for "all channels in use".

    The fourth issue of overlapping/obscured markers is definitely a problem. I like your idea of additional highlighting of the likely position marker.

    And I agree about the button names..
    WA2ZKDG8JNJ
  • TDoA maps

    Like the first suggestion and I almost implemented the second on this last update.

    I think I need to loosen up the criteria for "GPS is okay" so you don't have as much problem with the third issue. Same for "all channels in use".

    The fourth issue of overlapping/obscured markers is definitely a problem. I like your idea of additional highlighting of the likely position marker.

    And I agree about the button names..
    WA2ZKDG8JNJ
  • TDoA miniature waterfall

    Interesting idea. Remember that you can always double-click on the sampling station marker (blue) to open a regular Kiwi connection window in a new tab/window for monitoring. But having a little "snapshot" button on each line of the sampling station list that shows a short waterfall is a neat idea.
    I'll look into it.
    WA2ZKD