Waterfall and scale don't agree [they won't if there has been no frequency calibration]

sesykes71sesykes71
edited September 2018 in Problems Now Fixed
I have just noticed that the waterfall and scale are slightly different. It may have been this way before but I have never noticed it. If zoomed all the way in the center frequency of the waterfall is offset from the dial frequency, perhaps 1 or 2 Hz. I don't recall seeing it before. I believe it happened with the latest upgrade, if not just ignore this comment.

Comments

  • WA2ZKDWA2ZKD
    edited August 2018
    Hz? ...... edit: confirmed with him as Hz
  • KA7UKA7U
    How are you able to discern 1 or 2 Hz?



    Ron - KA7U
  • jksjks
    edited August 2018
    Any difference between the waterfall carrier of a known reference station and the frequency scale comes down to frequency calibration of the ADC XO clock.

    At z14 each waterfall FFT bin is roughly 0.9 Hz. But how this translates into what you see on your browser screen is a little muddled because those 2048 bins are "stretched" and anti-aliased to fit your actual visible screen width. But from experience the one above (not yours I know) looks fine for 5 MHz WWV.

    Do you have GPS clock correction working? Without GPS correction XO temperature variation may make the frequency offset at z14 look much worse than what you have. To see the exact ppm and Hz difference use the manual clock correction procedure (see admin page "config" tab). The XO spec is +/- 50 ppm @ 66.67 MHz without GPS correction operating.
    sesykes71
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