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Re: [softrock40] Re: SRv5 - 1/2 actual soundcard bandwidth - confusion ?!?

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  • Tony Parks
    Hi Vikki, Any place in the SoftRock circuit or connection to the soundcard that seriously affects one of the audio channels will result in little or no image
    Message 1 of 14 , Mar 2, 2006
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      Hi Vikki,

      Any place in the SoftRock circuit or connection to the soundcard that
      seriously affects one of the audio channels will result in little or no
      image rejection. This can include items on the OSC/BPF board, the QSD board
      or even the soundcard input. Some things to check wold include the
      following:

      1. R25 and C25 values on each of the OSC/BPF boards.
      In a number of cases the OSC/BPF kits were shipped with a 100k resistor for
      R25 rather than the correct value of 1k. Measure the resistance between
      pins 5 and 6 on the 15-pin header to make sure R25 is 1k. Read the value
      code on C25 to be 151 (150pF) for 40m and 470 (47pF) for 20m.

      2. Wiring on secondary of T21.
      The resistance between pin 9 and 10 on the 15-pin header should read about
      zero. Also the resistance between pins 9 and 11 should read about zero.
      Along with the correct resistance readings the wires connected to via 6 and
      via 3 on the T21 mounting position should come out of opposite side of the
      T21 core, one out of the top and one out of the bottom.

      3. If you have a scope then view the waveforms on pins 5 and 8 of the
      15-pin header. Both should be fairly symmetic square waves with the
      waveform on pin 8 lagging 90 degrees compared to the waveform on pin 5.
      (Circuit ground is at pin 12 of the header.)

      4. The DC voltage at pin 9 of the 15-pin header should be close to 2.5 VDC.

      5. The DC voltage at the + wire on C13 and C14 should both be close to 2.5
      VDC.

      6. Make sure you really are plugged into the line-in on your soundcard and
      the soundcard is selected by the SDR program in use.

      Hope the above make sense and will help a bit.

      73,
      Tony KB9YIG

      ----- Original Message -----
      From: "wrlabs" <pmudmap5@...>
      To: <softrock40@yahoogroups.com>
      Sent: Thursday, March 02, 2006 2:25 PM
      Subject: [softrock40] Re: SRv5 - 1/2 actual soundcard bandwidth - confusion
      ?!?


      > Hi Jean-Claude,
      >
      >> [ ... ]
      >> > This problem occurs on both the 40 and 20m LO/BPF boards so I
      >> [ ... ]
      >> This would confirm that the problem is on the QSD board.
      >
      > Thanks again!
      >
      > That does make sense, but the QSD was the last place I would have
      > looked as the QSD board was built and tested and then shipped to me,
      > maybe something got knocked loose in shipping ?!?
      >
      > I mostly suspected the LO/BPF boards as I built those myself :).
      >
      > Especially the 20m module where I broke off the 2N3904 during assembly
      > and for a while had it replaced with a 2N3906 before I caught that and
      > replaced it with a 2N3904 as it should have been. Funny that it
      > doesn't work at all with a PNP in place of an NPN :).
      >
      > I took the LO/BPF schematic and drew it up in gschem for the 20m
      > module specifically just to make troubleshooting easier. I'll check
      > that today and put it up on my SoftRock page, might make things a bit
      > easier for someone else. Plan on doing the same with the 40m module
      > just so I don't have to look through the data lines for each bands values.
      >
      > I did look at the 20m board under a magnifier last night and it looked
      > good, I am going to verify values today while I am at it today.
      >
      > This gets more exciting!
      >
      > Thanks & take care es 73, Vikki (WV9K/7)
      >
      >
      >
      >
      >
      >
      > Yahoo! Groups Links
      >
      >
      >
      >
      >
      >
      >
    • John Melton
      Some other things to check: 1. the values of R25 and C25 are the correct values. 2. you are using the line-in on the soundcard and it is stereo. 3. any shorts
      Message 2 of 14 , Mar 2, 2006
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        Some other things to check:

        1. the values of R25 and C25 are the correct values.
        2. you are using the line-in on the soundcard and it is stereo.
        3. any shorts on the I and Q audio cable to the sound card.

        Regards,

        John g0orx/n6lyt

        wrlabs wrote:
        > Hi Jean-Claude,
        >
        > > [ ... ]
        > > > This problem occurs on both the 40 and 20m LO/BPF boards so I
        > > [ ... ]
        > > This would confirm that the problem is on the QSD board.
        >
        > Thanks again!
        >
        > That does make sense, but the QSD was the last place I would have
        > looked as the QSD board was built and tested and then shipped to me,
        > maybe something got knocked loose in shipping ?!?
        >
        > I mostly suspected the LO/BPF boards as I built those myself :).
        >
        > Especially the 20m module where I broke off the 2N3904 during assembly
        > and for a while had it replaced with a 2N3906 before I caught that and
        > replaced it with a 2N3904 as it should have been. Funny that it
        > doesn't work at all with a PNP in place of an NPN :).
        >
        > I took the LO/BPF schematic and drew it up in gschem for the 20m
        > module specifically just to make troubleshooting easier. I'll check
        > that today and put it up on my SoftRock page, might make things a bit
        > easier for someone else. Plan on doing the same with the 40m module
        > just so I don't have to look through the data lines for each bands values.
        >
        > I did look at the 20m board under a magnifier last night and it looked
        > good, I am going to verify values today while I am at it today.
        >
        > This gets more exciting!
        >
        > Thanks & take care es 73, Vikki (WV9K/7)
        >
        >
        >
        >
        >
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      • Guido
        Hi Vikki, The noise problem, could be due to a bad crystal. My 20m crystal behaves bad and causes about 20db noise over the whole band compared to another
        Message 3 of 14 , Mar 2, 2006
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          Hi Vikki,

          The noise problem, could be due to a bad crystal. My 20m crystal behaves bad and causes about 20db noise over the whole band compared to another crystal or LC replacement.

          What also can cause the noise, is that the mixer input setting is not preserved in de soundcard driver. Selecting again the input port line-in will solve. I do not recommend to use mic input port.

          Guido


          On 3/1/06, wrlabs <pmudmap5@...> wrote:
          Hi folks,

            I'm real confused here and I have not found and answer for this, so
          please let me pester all the experts out here :-).

            I have the SRv5 with the 40m and 20m LO/BPF modules.  On the
          computer I (reluctantly :) put windoz on to deal with this (old
          Thunderbird 1100 / 512M RAM / MSI-K7T-PRO2-A motherboard) I am using
          the built in AC97 sound.

          Using Rocky and M0KGK I see the same thing.

            I ***APPEARS*** to me that only half of the banwidth shown is real,
          the other half is a mirror?!?

            I have NOISE problems here and am lucky when a signal gets through,
          but I finally got enough of a good day here to get several signals
          going through the 20m module.  This time long enough to do some checking.

            There is a central spike in the display corresponding to the LO
          crystal frequency and a couple smaller spikes very close to that one.

            Signals are mirrored on the opposite side of the central spike, or
          so it certainly seems to be here.

            A couple pix of this for reference:

          http://wrlabs.shacknet.nu/~vw/hamradio/SoftRockV5/

            I wander back and forth between this is right (mix products) and
          maybe I have something wrong? Yes, confuzed-r-us :-).

            One last question, I have a spare SB Live! floating around, would
          that be any better than the onboard AC97 (Delta is not in the budget :)?

            Any thoughts appreciated!

          Thanks & take care es 73, Vikki.








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        • wrlabs
          Thanks **VERY** much to all who responded to this. Thanks to your gracious efforts I good idea of where to go from here. I did finish up the schematics for the
          Message 4 of 14 , Mar 2, 2006
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            Thanks **VERY** much to all who responded to this.

            Thanks to your gracious efforts I good idea of where to go from here.

            I did finish up the schematics for the 20m and 40m LO/BPF boards, you
            can find them at:

            http://wrlabs.shacknet.nu/~vw/hamradio/SoftRockV5/

            Hopefully they will help in some way.

            Again, thanks!

            Take care es 73, Vikki (WV9K/7)
          • John Seager
            Vikki I am not an expert but have had a similar problem with mirror image response on either side of the midline when using SRv 5.0 with Rocky and an onboard
            Message 5 of 14 , Mar 3, 2006
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              Vikki
              I am not an expert but have had a similar problem with mirror image response on either side of the midline when using SRv 5.0 with Rocky and an onboard AC97 soundcard. Using the I2PHD SDRadio programme the unwanted images to the left of the midline disappear almost completely if the sound card channel skew calibration is set to give a delay of about -14 microseconds. Because of this I have assumed that the problem lies in the AC97 sound card and that an M-Audio Delta 44 would eliminate the problem. Of course it might not... John  G0UCP
            • wrlabs
              Hi Folks, After going over the boards and finding no problems, I tracked back down the cables and the one to the soundcard had pulled about halfway out of the
              Message 6 of 14 , Mar 4, 2006
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                Hi Folks,

                After going over the boards and finding no problems, I tracked back
                down the cables and the one to the soundcard had pulled about halfway
                out of the extension cable.

                Rule One still applies :-) Make sure it is plugged in! LOL.

                To all who responded, again, thanks MUCH!

                Is there any point to replacing the AC97 with an SB Live! ?

                Thanks & take care es 73, Vikki (WV9k/7)
              • KD5NWA
                On many of my PC s the built in AC97 card work quite well, some of them are very quiet in terms of noise and hum pickup. But the Sound Blaster Live 24 PCI has
                Message 7 of 14 , Mar 4, 2006
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                  On many of my PC's the built in AC97 card work quite well, some of
                  them are very quiet in terms of noise and hum pickup. But the Sound
                  Blaster Live 24 PCI has the advantage of 24 bit resolution, which you
                  can notice when there are weak signals, and it's less than $30 in most places.

                  I would say if you can afford it go for it, but beware some of the
                  higher price SB cards don't give you enough increased performance
                  compared to their cost increase. Also their USB versions take a much
                  heavier toll in terms of increases CPU usage compared to their PCI
                  cousins, that is specially important if you don't have a top end computer.

                  Have fun.:-)


                  At 11:45 AM 3/4/2006, you wrote:

                  >Hi Folks,
                  >
                  >After going over the boards and finding no problems, I tracked back
                  >down the cables and the one to the soundcard had pulled about halfway
                  >out of the extension cable.
                  >
                  >Rule One still applies :-) Make sure it is plugged in! LOL.
                  >
                  >To all who responded, again, thanks MUCH!
                  >
                  >Is there any point to replacing the AC97 with an SB Live! ?
                  >
                  >Thanks & take care es 73, Vikki (WV9k/7)
                  >
                  >
                  >
                  >
                  >
                  >
                  >
                  >Yahoo! Groups Links
                  >
                  >
                  >
                  >


                  Cecil Bayona
                  KD5NWA
                  www.qrpradio.com

                  "Windows the worlds most successful software virus"
                • wrlabs
                  Hello Cecil, Thanks for the info here, it sure clears up a number of questions I had! Much appreciated! I found one at NewEgg and will probably go ahead and
                  Message 8 of 14 , Mar 5, 2006
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                    Hello Cecil,

                    Thanks for the info here, it sure clears up a number of questions I
                    had! Much appreciated!

                    I found one at NewEgg and will probably go ahead and order it.

                    Thanks & take care es 73, Vikki (WV9K/7)



                    --- In softrock40@yahoogroups.com, KD5NWA <KD5NWA@...> wrote:
                    >
                    > On many of my PC's the built in AC97 card work quite well, some of
                    > them are very quiet in terms of noise and hum pickup. But the Sound
                    > Blaster Live 24 PCI has the advantage of 24 bit resolution, which you
                    > can notice when there are weak signals, and it's less than $30 in
                    most places.
                    >
                    > I would say if you can afford it go for it, but beware some of the
                    > higher price SB cards don't give you enough increased performance
                    > compared to their cost increase. Also their USB versions take a much
                    > heavier toll in terms of increases CPU usage compared to their PCI
                    > cousins, that is specially important if you don't have a top end
                    computer.
                    >
                    > Have fun.:-)
                    >
                    > Cecil Bayona
                    > KD5NWA
                    > www.qrpradio.com
                    >
                    > "Windows the worlds most successful software virus"
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