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96Re: [wsjtgroup] FSK441 Reports

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  • Rex Moncur
    Apr 21, 2002
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      Hi Andrew Flowers and Arthur Jackson

      Thanks for your replies. I am doing a paper on WSJT for our VK VHF
      conference and I thought someone might ask a question about the reports -
      hence the reason for asking the question.

      I don't get completely consistent results but I think the answer is
      something like:

      0 = 40 ms or less
      1 = 40 ms to 150 ms
      2 = 150 ms to 5 seconds
      and I assume that
      3 = 5 seconds to 15 seconds
      4 = 15 to 60 seconds
      5 = 0ver 60 second

      In terms of the dB scale it seems that:

      6 = up to 10 dB
      7 = 10 dB to 15 dB
      8 = above 15 dB

      I have not got anything above 38 so I make assumptions after that.

      I agree with Andy that large pings tend to be compressed but I think this is
      due to the algorithm in the WSJT rather than Receiver AGC action. In some
      tests I have done with a signal generator and my FT-847 I don't get the
      compression with other programs such as Spectrogam - at least up to 30 dB.

      My suspicion is that WSJT is reporting the peak strength of the ping
      relative to the average signal level in the 30 second period and this causes
      the compression because of the increased average signal on long pings

      However, independent of whether it is the program or the receiver producing
      the compression I think Andy is right to use the suggested signal reports
      only as a guide and to make your reports on the basis of what you hear and
      your intuition.

      In terms of duration I think there is no option but to use your intuition
      (to quote Andrew) for longer pings or measure the length of the ping/burn on
      the green signal strength line as WSJT usually breaks up long pings/burns
      into multiple signals.

      73 Rex, VK7MO
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