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Re: [dxatlas] Re: CW Skimmer 1.1 doesn't allow for transceivers with more than 3 KHz bandwidth

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  • Pete Smith
    I think this is two different issues. Jerry is talking about the 3 KHz radio mode, which uses a soundcard to decode the audio from the receiver. Bill is
    Message 1 of 19 , Apr 22, 2008
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      I think this is two different issues. Jerry is talking about the 3 KHz
      radio mode, which uses a soundcard to decode the audio from the receiver.

      Bill is running into a different thing, I believe. Bill, if you use the
      SoftRock-IF radio choice, how much bandwidth do you see? What about if you
      use the basic SoftRock position, using the LO frequency to define the
      center of the display range.

      73, Pete N4ZR

      At 07:04 AM 4/22/2008, bill_w4zv wrote:
      >--- In dxatlas_group@yahoogroups.com, "jeraldvolpe" <techmail@...> wrote:
      >
      > > I just installed version 1.1 over my version 1.0. I appreciate the
      > > changes but I am disappointed that you are still limiting standard
      > > transceivers to a 3 kHz maximum skim! I wrote several times regarding
      > > those of us with transceivers that can open up beyond 3kHz. I am one
      > > of several thousand Ten-Tec Orion and Orion II owners (a transceiver
      > > that is heavily used in contests and serous DXing) and we are able to
      > > open up our receivers to 8 kHz in the CW mode... especially our second
      > > receiver which doesn't share the roofing filters of the main receiver.
      >
      >Same here. I'm using a beta version of N8LP's LP-PAN which provides
      >I-Q detection for the Elecraft K3's wideband buffered output. It
      >seems my Skimmer is also limited to 3 kHz. Are you working on an
      >interface to LP-PAN that will be friendlier than using Softrock mode?
      >
      >Maybe I don't have things adjusted correctly yet but so far I'm not
      >seeing Skimmer decode signals in noise very well.
      >
      >73, Bill W4ZV
      >
      >
      >------------------------------------
      >
      >Yahoo! Groups Links
      >
      >
      >
    • bill_w4zv
      Hi Pete, ... the ... I m only seeing 3 kHz on the display but I think it may be capturing signals further away...the bands are so poor I m having trouble
      Message 2 of 19 , Apr 23, 2008
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        Hi Pete,

        > Bill is running into a different thing, I believe. Bill, if you use
        the
        > SoftRock-IF radio choice, how much bandwidth do you see?

        I'm only seeing 3 kHz on the display but I think it may be capturing
        signals further away...the bands are so poor I'm having trouble
        finding enough signals strong enough to test! I'm sampling at 48 kHz
        since I'm running an underpowered CPU (1.1GHz P3 + 1GB RAM > Delta 44
        > LP-PAN > K3). As I said before I'm a little disappointed with
        Skimmer's ability to decode weak signals so far but I may not have
        everything set up correctly. I can plainly hear some Q5 signals that
        Skimmer seems to have difficulty decoding.

        > What about if you
        > use the basic SoftRock position, using the LO frequency to define the
        > center of the display range.

        I haven't tried that yet...it may be beyond my beginner's skills at
        this stage. The K3's IF out is 8.215 kHz, so should I set something
        like 8239 (8215+24)? That seems to be what the "Softrock-IF"
        documentation says but I haven't read everything carefully enough to
        even ask an intelligent question! I don't think Alex has yet
        documented the Skimmer's setup for using the K3's wideband IF out.

        It does seem to work very nicely with OmniRig in Softrock-IF mode but
        I'm just not seeing the wideband display.

        73, Bill
      • bill_w4zv
        ... Since the bands are so poor I downloaded the pileup file (FJ/OH2AM) and my system seemed to handle it fairly well. 67 calls identified between 7006.4 and
        Message 3 of 19 , Apr 23, 2008
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          --- In dxatlas_group@yahoogroups.com, "bill_w4zv" <w0zv@...> wrote:

          > I'm only seeing 3 kHz on the display but I think it may be capturing
          > signals further away...the bands are so poor I'm having trouble
          > finding enough signals strong enough to test! I'm sampling at 48 kHz
          > since I'm running an underpowered CPU (1.1GHz P3 + 1GB RAM > Delta 44
          > > LP-PAN > K3).

          Since the bands are so poor I downloaded the pileup file (FJ/OH2AM)
          and my system seemed to handle it fairly well. 67 calls identified
          between 7006.4 and 7018.9 with about 71% CPU utilization (i.e. not
          maxing out). But for some reason my Skimmer display still only shows
          about 3 kHz at a time...maybe I just haven't yet discovered how to
          enable the wide display.

          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?

          A couple of things strike me so far:

          1. Is it possible to suppress decoders for zero point station QRGs
          once they are identified? 23 of the 58 in the last run were USA.
          This would make for a less cluttered display and probably free up some
          resources. I suppose USA calls would be eliminated from a band map in
          a contest program anyway but am just curious.

          2. I'm not sure how well Skimmer will work with very weak signals.
          It seems to pick up signals with good S/N very well but I'm wondering
          how it might work for weak DX signals on a band like 160? Has anyone
          had much experience with weak signals? It could be I'm still not set
          up correctly but it seems like you need a real S5 signal or better for
          it to decode calls quickly. I can hear many Q5 signals on the K3 that
          don't even register solidly on Skimmer's waterfall.

          I definitely plan to upgrade my computer eventually but am just
          playing with what I have for now and am curious about others' experiences.

          73, Bill
        • Pete Smith
          ... 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
          Message 4 of 19 , Apr 24, 2008
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            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
          • rt_tclay
            Is the reason you only see 3 KHz because you haven t resized the Skimmer window? Just drag the bottom edge to make it bigger. Tor N4OGW
            Message 5 of 19 , Apr 25, 2008
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              Is the reason you only see 3 KHz because you haven't resized the
              Skimmer window? Just drag the bottom edge to make it bigger.

              Tor
              N4OGW
            • rt_tclay
              ... with Similar results here on the CQWW file. Running with graphics window shrunk down. XP Pro SP2. 1) old 1 GHz AMD Athlon. 1.25 GB RAM maxed out 100% CPU,
              Message 6 of 19 , Apr 25, 2008
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                --- 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


                Similar results here on the CQWW file. Running with graphics window
                shrunk down. XP Pro SP2.

                1) old 1 GHz AMD Athlon. 1.25 GB RAM

                maxed out 100% CPU, decoded only 69 calls

                2) 1.8 GHz AMD Sempron ("3100+" model I think), 1 GB RAM

                max CPU 70-80%, 155 calls


                Given that CPU never hit 100% on the second system, I would say that
                throwing more CPU at it won't give more calls decoded. Of course if
                it ran for longer, the number of decoders might increase enough to
                hit 100%. I think to test performance on faster CPU's you need a
                longer sample.

                Tor
                N4OGW
              • bill_w4zv
                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
                Message 7 of 19 , 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
                  >
                • rt_tclay
                  ... not ... decoders ... seen I don t know for sure, but I think the program just uses the green bar setting for the audio output filter width. I can copy
                  Message 8 of 19 , Apr 26, 2008
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                    --- In dxatlas_group@yahoogroups.com, "bill_w4zv" <w0zv@...> wrote:
                    >
                    > 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

                    I don't know for sure, but I think the program just uses the green
                    bar setting for the audio output filter width.

                    I can copy better than Skimmer on weak signals. If you watch it
                    trying to copy a weak signal, it usually gets a few letters correct
                    each time, but has a hard time putting together the full correct
                    callsign. That's where the brain obviously has an advantage, when you
                    are copying you can say definitely if you copied a particular letter
                    and mark that mentally as "good copy".

                    If on your computer Skimmer is reaching 100% cpu, then yes, it is
                    having to reduce the number of decoders. I don't know the algorithm
                    used to do that, but yes, it might do that based signal strength. Try
                    reducing the bandwidth. My old 1GHz Athlon can't keep up with 96 KHz,
                    but is ok at 48 KHz if the band isn't too busy.

                    Tor
                    N4OGW
                  • Pete Smith
                    ... Hi Bill - I think you may need to do some experimenting to maximize Skimmer s weak-signal performance. I may have mentioned this already, but a great deal
                    Message 9 of 19 , Apr 26, 2008
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                      At 09:20 AM 4/26/2008, bill_w4zv wrote:
                      >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.

                      Hi Bill - I think you may need to do some experimenting to maximize
                      Skimmer's weak-signal performance. I may have mentioned this already, but
                      a great deal depends on the dynamic range of the line input of your
                      soundcard. Whichever card you use, you need to make sure that the input
                      gain is set just short of clipping, in order to get the closest possible
                      approximation of the sensitivity of the receiver alone. and of course, you
                      are comparing it with one of the best receivers ever made - no fair hi.

                      73, Pete N4ZR
                    • Pete Smith
                      ... One of the most effective tricks is to uncheck the Adaptive decoder box, and set a specified maximum number of decoders. Hitting 100% isn t so
                      Message 10 of 19 , Apr 26, 2008
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                        At 02:01 PM 4/26/2008, rt_tclay wrote:
                        >If on your computer Skimmer is reaching 100% cpu, then yes, it is
                        >having to reduce the number of decoders. I don't know the algorithm
                        >used to do that, but yes, it might do that based signal strength. Try
                        >reducing the bandwidth. My old 1GHz Athlon can't keep up with 96 KHz,
                        >but is ok at 48 KHz if the band isn't too busy.


                        One of the most effective tricks is to uncheck the "Adaptive" decoder box,
                        and set a specified maximum number of decoders. Hitting 100% isn't so
                        important, in my view, as eliminating most of the junk you get from
                        Skimmer's trying to decode on RTTY signals. If you set a maximum number of
                        decoders, Alex says that Skimmer accommodates that by narrowing the band of
                        frequencies that it attempts to decode, centered around the center
                        frequency of the waterfall display. Experimentally, I discovered that 150
                        decoders seemed pretty much to eliminate anything above about 14060 on a
                        normally busy weekend band, when I set the waterfall on 14030. Today,
                        running 300 decoders, I'm getting a lot of "AA4EE" type "callsigns" in the
                        14070 and above range. During a major contest, you might have to set it to
                        a higher number to get the same approximate frequency coverage.

                        73, Pete N4ZR
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