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805Re: Decoding performance

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  • bill_w4zv
    Apr 26, 2008
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      Thanks Pete and Tor! Yes Tor, I simply had not discovered how to
      increase the window size on the display.

      How do you feel about Skimmer's ability to decode weaker signals in
      QSB and QRN? I'm somewhat unimpressed so far but it could be I'm not
      doing something right. Does the DSP filter width affect all decoders
      or just the one displayed with the green bar? Based on what I've seen
      so far, Skimmer would be great for identifying strong stations CQ-ing
      or in a pileup but it doesn't work very well for weaker signals, which
      would likely be the very ones you want to know about. But this could
      be due to my not setting Skimmer up correctly or due to my weak
      computer. BTW, I noticed 3GHz P4's on eBay go for <$150 so I may pick
      up one of these to solve the latter issue.

      73, Bill W4ZV


      --- In dxatlas_group@yahoogroups.com, Pete Smith <n4zr@...> wrote:
      >
      > At 05:19 PM 4/23/2008, bill_w4zv wrote:
      > >I then tried the CQWW file below and got the following results, with
      > >CPU utilization hitting 100% at times in all cases:
      > >
      >
      >http://cid-e39b59612b664f63.skydrive.live.com/self.aspx/Public/CQWWCW_2005_1_of_42.wav
      > >
      > >33 calls, 7009.0>7020.10, everything running on computer.
      > >33 calls, same QRG range, Internet connection and browser off.
      > >40 calls, 7007.0>7021.9, AVG anti-virus off.
      > >58 calls, 7002.0>7024.6, Skimmer display minimized.
      > >
      > >I could probably do a little better by shutting down more background
      > >processes but I'm curious what someone with a 2-3 GHz CPU gets when
      > >running the same CQWW file above?
      >
      >
      > Your wish is my command, sir ;^)
      >
      > With a 2.2 GHz Celeron, 768 MB DDR RAM (a VERY basic Dell 2400, four
      years
      > old, With XP home SP2) I got the following results off the same file.
      >
      > Note that when playing back recordings the sound card is not involved;
      > Skimmer is processing the I/Q file directly, so settings like playback
      > sampling rate have no effect:
      >
      > Decoders Other variables Calls Decoded CPU
      peak
      > utilization
      >
      > Adaptive Not minimized 156 96%
      > 250 "" 131 75%
      > 300 "" 152 81%
      > 350 "" 154 86%
      > 400 "" 153 100%
      > Adaptive Telnet server off 154 100%
      > Adaptive Skimmer minimized 154 ?
      >
      > Interesting, no? I would have to other programs minimized or in the
      > background do not affect decoding performance; one of the critical
      > questions I hope to answer in coming months is whether the reverse
      is true,
      > since we're talking about using Skimmer to feed spots to a contest
      logging
      > program, which has to be able to respond quickly, send CW, etc. My
      > personal tests with N1MM logger, using a Winkey for CW, have been very
      > encouraging; I suspect that MM simply takes precedence when it needs
      to,
      > and that the Winkey avoids any issues with making good CW.
      >
      > 73, Pete N4ZR
      >
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