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

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  • Alex, VE3NEA
    Hi Jerry, Thank you for your suggestions, I have added them to my list of requested features. Meanwhile you may want to try and feed CW Skimmer with the 14-kHz
    Message 1 of 19 , Mar 29, 2008
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      Hi Jerry,

      Thank you for your suggestions, I have added them to my list of requested
      features. Meanwhile you may want to try and feed CW Skimmer with the 14-kHz
      IF signal from your Orion. The Skimmer may be able to process it in the
      SoftRock-IF mode.

      73 Alex VE3NEA



      ----- Original Message -----
      From: "jeraldvolpe" <techmail@...>
      To: <dxatlas_group@yahoogroups.com>
      Sent: Saturday, March 29, 2008 02:43 PM
      Subject: [dxatlas] CW Skimmer 1.1 doesn't allow for transceivers with more
      than 3 KHz bandwidth....


      Alex,

      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.

      Perhaps there a way I can fudge the 'software defined radio' settings
      to work? I haven't figured out a magic set of settings so far...
      Seriously Alex, being able to open up that 3KHz window to 4, 5, ....
      or in Orion owners situation... 8 kHz would truly add to the power of
      CW Skimmer.

      I had already mentioned a request to allow selectable use of one or
      the other of the transceivers two VFOs. I don't see any mention of
      that in this release either. Now I modified my OmniRig Orion
      definition file to trick CW Skimmer to read and modify the second VFO,
      but I don't think most users are up to that level of control file
      modification. Couldn't this be added within CW Skimmer for those who's
      transceivers have second receivers?

      Also another future 'enhancement' to consider might be something like
      a 'sticky preset' that we could use to set a CW Skimmer preset
      frequency so that we can quickly return to a known base frequency. For
      example, the DX is listening up 5 to 10 kHz.... right now my second
      receiver/transmitter starts at that point but as soon as I click on a
      signal in the CW Skimmer waterfall the original reference point is
      lost. Many DX jump around not following a specific pattern of slowly
      up or down.... so having a 'sticky preset' we could quickly return to
      that base skim point and proceed up from there.

      Please don't think my comments in any way reduce what is an exemplary
      software tool for amateur radio CW ops.... just love to see it be even
      more for many of us.

      73,
      Jerry, KG6TT
    • Pete Smith
      Sure Ed - I envy you that radio, but most of us are stuck with hardware. I presume Alex wrote Skimmer with a 3 KHz limit to avoid confusing users. 73, Pete
      Message 2 of 19 , Mar 30, 2008
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        Sure Ed - I envy you that radio, but most of us are stuck with hardware. I
        presume Alex wrote Skimmer with a 3 KHz limit to avoid confusing users.

        73, Pete

        At 07:54 PM 3/29/2008, Ed Russell wrote:
        >Pete,
        >
        >I set up my Flex5k to output 8khz of bandwidth to Skimmer via VAC. In
        >Skimmer I can only see 3khz, and I don't see any calls outside that
        >bandwidth appearing in the call list.
        >
        >73 Ed W2RF
        >
        >On 29 Mar 2008 at 17:40, Pete Smith wrote:
        >
        > >
        > > Jerry, I think that the rub is that the 3-KHz mode uses audio, and the
        > > audio passband of your radio rolls off pretty steeply above 3 KHz,
        > > even if
        > > your IF bandwidth is out to 8 KHz or more.
        > >
        > > 73, Pete N4ZR
        > >
        > > -At 02:43 PM 3/29/2008, you wrote:
        > > >Alex,
        > > >
        > > >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.
        > > >
        > > >Perhaps there a way I can fudge the 'software defined radio' settings
        > > >to work? I haven't figured out a magic set of settings so far...
        > > >Seriously Alex, being able to open up that 3KHz window to 4, 5, ....
        > > >or in Orion owners situation... 8 kHz would truly add to the power of
        > > >CW Skimmer.
        > > >
        > > >I had already mentioned a request to allow selectable use of one or
        > > >the other of the transceivers two VFOs. I don't see any mention of
        > > >that in this release either. Now I modified my OmniRig Orion
        > > >definition file to trick CW Skimmer to read and modify the second
        > > VFO,
        > > >but I don't think most users are up to that level of control file
        > > >modification. Couldn't this be added within CW Skimmer for those
        > > who's
        > > >transceivers have second receivers?
        > > >
        > > >Also another future 'enhancement' to consider might be something like
        > > >a 'sticky preset' that we could use to set a CW Skimmer preset
        > > >frequency so that we can quickly return to a known base frequency.
        > > For
        > > >example, the DX is listening up 5 to 10 kHz.... right now my second
        > > >receiver/transmitter starts at that point but as soon as I click on a
        > > >signal in the CW Skimmer waterfall the original reference point is
        > > >lost. Many DX jump around not following a specific pattern of slowly
        > > >up or down.... so having a 'sticky preset' we could quickly return to
        > > >that base skim point and proceed up from there.
        > > >
        > > >Please don't think my comments in any way reduce what is an exemplary
        > > >software tool for amateur radio CW ops.... just love to see it be
        > > even
        > > >more for many of us.
        > > >
        > > >73,
        > > >Jerry, KG6TT
        > > >
        > > >
        > > >------------------------------------
        > > >
        > > >Yahoo! Groups Links
        > > >
        > > >
        > > >
        > >
        > >
        >
        >
        >
        >
        >------------------------------------
        >
        >Yahoo! Groups Links
        >
        >
        >
      • jeraldvolpe
        Actually the audio does NOT role off in the Orion if you are not utilizing roofing filters to limit it.... which is the case when you are using the sub
        Message 3 of 19 , Mar 30, 2008
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          Actually the audio does NOT role off in the Orion if you are not
          utilizing roofing filters to limit it.... which is the case when you
          are using the sub receiver. It you have receive EQ on '0'. I have done
          low signal sweeps using an audio spectrum display and find equal noise
          and signal patterns from under 100Hz to 8kHz.

          73,
          Jerry, KG6TT

          --- In dxatlas_group@yahoogroups.com, Pete Smith <n4zr@...> wrote:
          >
          > Jerry, I think that the rub is that the 3-KHz mode uses audio, and the
          > audio passband of your radio rolls off pretty steeply above 3 KHz,
          even if
          > your IF bandwidth is out to 8 KHz or more.
          >
          > 73, Pete N4ZR
          >
          > -At 02:43 PM 3/29/2008, you wrote:
          > >Alex,
          > >
          > >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.
          > >
          > >Perhaps there a way I can fudge the 'software defined radio' settings
          > >to work? I haven't figured out a magic set of settings so far...
          > >Seriously Alex, being able to open up that 3KHz window to 4, 5, ....
          > >or in Orion owners situation... 8 kHz would truly add to the power of
          > >CW Skimmer.
          > >
          > >I had already mentioned a request to allow selectable use of one or
          > >the other of the transceivers two VFOs. I don't see any mention of
          > >that in this release either. Now I modified my OmniRig Orion
          > >definition file to trick CW Skimmer to read and modify the second VFO,
          > >but I don't think most users are up to that level of control file
          > >modification. Couldn't this be added within CW Skimmer for those who's
          > >transceivers have second receivers?
          > >
          > >Also another future 'enhancement' to consider might be something like
          > >a 'sticky preset' that we could use to set a CW Skimmer preset
          > >frequency so that we can quickly return to a known base frequency. For
          > >example, the DX is listening up 5 to 10 kHz.... right now my second
          > >receiver/transmitter starts at that point but as soon as I click on a
          > >signal in the CW Skimmer waterfall the original reference point is
          > >lost. Many DX jump around not following a specific pattern of slowly
          > >up or down.... so having a 'sticky preset' we could quickly return to
          > >that base skim point and proceed up from there.
          > >
          > >Please don't think my comments in any way reduce what is an exemplary
          > >software tool for amateur radio CW ops.... just love to see it be even
          > >more for many of us.
          > >
          > >73,
          > >Jerry, KG6TT
          > >
          > >
          > >------------------------------------
          > >
          > >Yahoo! Groups Links
          > >
          > >
          > >
          >
        • jeraldvolpe
          ... requested ... 14-kHz ... I m considering your suggestion to tap into the Orion s IF. Question: Have you considered an RTTY Skimmer? It would be equally
          Message 4 of 19 , Mar 30, 2008
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            --- In dxatlas_group@yahoogroups.com, "Alex, VE3NEA" <alshovk@...> wrote:
            >
            > Hi Jerry,
            >
            > Thank you for your suggestions, I have added them to my list of
            requested
            > features. Meanwhile you may want to try and feed CW Skimmer with the
            14-kHz
            > IF signal from your Orion. The Skimmer may be able to process it in the
            > SoftRock-IF mode.
            >
            > 73 Alex VE3NEA

            I'm considering your suggestion to tap into the Orion's IF.

            Question: Have you considered an RTTY Skimmer? It would be equally
            useful and probably would utilize a large portion of the code you have
            already developed. It certainly has to be easier decoding RTTY which
            has to follow one of but a few shift, speed and possible inversion
            patterns. Food for thought (as if you are just sitting around looking
            for things to do. :)

            73,
            Jerry, KG6TT
          • bill_w4zv
            ... 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
            Message 5 of 19 , Apr 22, 2008
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              --- 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
            • 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 6 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 7 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 8 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 9 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 10 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 11 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 12 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 13 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 14 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 15 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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