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Re: [softrock40] SoftRock V6 with AD9951

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  • Ben Hall
    Hi John and group, Crystal clear! (pun not intended, but I guess its a little funny) thanks and 73, ben, KD5BYB
    Message 1 of 14 , Jul 4, 2006
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      Hi John and group,

      Crystal clear! (pun not intended, but I guess its a little funny)

      thanks and 73,
      ben, KD5BYB

      John Melton wrote:
      >
      >
      > Hi Ben,
      >
      > In all cases I have not populated Xtal/2n3904 oscillator circuit and I
      > have also put a 50 ohm termination across the input from the DDS-60.
      >
      > V4 - DDS-60 input to C8.
      > V5 - DDS-60 input to pin 4 of J1 on QSD board with 47pF cap in series.
      > V6 - DDS-60 input to C7
      > V7 - DDS-60 input to C6
      >
      > Hope that helps,
      >
      > Regards,
      >
      > John g0orx/n6lyt
    • n3hkn
      John, You seem to have a lot of experience with the DDS60 as a VFO driving the SoftRock series. My experience has been with the V5 where I found the amount of
      Message 2 of 14 , Jul 4, 2006
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        John,
        You seem to have a lot of experience with the DDS60 as a VFO driving
        the SoftRock series. My experience has been with the V5 where I found
        the amount of spurs in the bandpass to be high (amount) enough to set
        the DDS60 aside as a VFO. Do you find the number and amplitude of the
        spurs excessive (used as a VFO) in your experience?

        The one thing I did not do was to put 50ohms across the DDS60. I would
        guess that the resistor should be placed before the 47pf cap??

        Dick N3HKN

        --- In softrock40@yahoogroups.com, John Melton <john.melton@...> wrote:
        >
        > Hi Ben,
        >
        > In all cases I have not populated Xtal/2n3904 oscillator circuit and I
        > have also put a 50 ohm termination across the input from the DDS-60.
        >
        > V4 - DDS-60 input to C8.
        > V5 - DDS-60 input to pin 4 of J1 on QSD board with 47pF cap in series.
        > V6 - DDS-60 input to C7
        > V7 - DDS-60 input to C6
        >
        > Hope that helps,
        >
        > Regards,
        >
        > John g0orx/n6lyt
        >
        > Ben Hall wrote On 07/03/06 23:12,:
        >
        > > Hi John,
        > >
        > > How/where do you connect the DDS-60 to your various versions of the
        > > softrock?
        > >
        > > thanks and 73,
        > > ben, KD5BYB
        > >
        > > John Melton wrote:
        > > > I have a DDS-60 from AMQRP
        > > http://www.amqrp.org/kits/dds60/index.html
        > > <http://www.amqrp.org/kits/dds60/index.html>
        > > > <http://www.amqrp.org/kits/dds60/index.html
        > > <http://www.amqrp.org/kits/dds60/index.html>>
        > > > that I use with several different versions of the SoftRock.
        Apart from
        > > > some spurs, which can be avoided, it works well. Just make sure that
        > > > you have a good 50 ohm termination.
        > > >
        > > > Regards,
        > > >
        > > > John g0orx/n6lyt
        > >
        > >
        >
        >
        > --
        > --
        > John Melton
        > Sun IT CTO
        > Office: +44 1252 421708 (ext 21708)
        > Mobile: +44 7714 708861
        >
      • John Melton
        The 50 ohm termination does help somewhat and, yes, it is before the 47pf cap. There are still frequencies where there are many spurs across the 48/96 KHz
        Message 3 of 14 , Jul 4, 2006
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          The 50 ohm termination does help somewhat and, yes, it is before the
          47pf cap. There are still frequencies where there are many spurs across
          the 48/96 KHz bandwidth but you can easily offset the DDS-60 to a
          frequency that has none or minimal spurs and use the software to tune
          the required frequency.

          I have been experimenting with some code for a version of my Java GUI
          for DttSP that is similar to the spur reduction code in PowerSDR but
          modified for the AD9951. I plan on making that code part of the release
          for DttSP2.

          John

          n3hkn wrote On 07/04/06 14:41,:

          > John,
          > You seem to have a lot of experience with the DDS60 as a VFO driving
          > the SoftRock series. My experience has been with the V5 where I found
          > the amount of spurs in the bandpass to be high (amount) enough to set
          > the DDS60 aside as a VFO. Do you find the number and amplitude of the
          > spurs excessive (used as a VFO) in your experience?
          >
          > The one thing I did not do was to put 50ohms across the DDS60. I would
          > guess that the resistor should be placed before the 47pf cap??
          >
          > Dick N3HKN
          >
          > --- In softrock40@yahoogroups.com
          > <mailto:softrock40%40yahoogroups.com>, John Melton <john.melton@...>
          > wrote:
          > >
          > > Hi Ben,
          > >
          > > In all cases I have not populated Xtal/2n3904 oscillator circuit and I
          > > have also put a 50 ohm termination across the input from the DDS-60.
          > >
          > > V4 - DDS-60 input to C8.
          > > V5 - DDS-60 input to pin 4 of J1 on QSD board with 47pF cap in series.
          > > V6 - DDS-60 input to C7
          > > V7 - DDS-60 input to C6
          > >
          > > Hope that helps,
          > >
          > > Regards,
          > >
          > > John g0orx/n6lyt
          > >
          > > Ben Hall wrote On 07/03/06 23:12,:
          > >
          > > > Hi John,
          > > >
          > > > How/where do you connect the DDS-60 to your various versions of the
          > > > softrock?
          > > >
          > > > thanks and 73,
          > > > ben, KD5BYB
          > > >
          > > > John Melton wrote:
          > > > > I have a DDS-60 from AMQRP
          > > > http://www.amqrp.org/kits/dds60/index.html
          > <http://www.amqrp.org/kits/dds60/index.html>
          > > > <http://www.amqrp.org/kits/dds60/index.html
          > <http://www.amqrp.org/kits/dds60/index.html>>
          > > > > <http://www.amqrp.org/kits/dds60/index.html
          > <http://www.amqrp.org/kits/dds60/index.html>
          > > > <http://www.amqrp.org/kits/dds60/index.html
          > <http://www.amqrp.org/kits/dds60/index.html>>>
          > > > > that I use with several different versions of the SoftRock.
          > Apart from
          > > > > some spurs, which can be avoided, it works well. Just make sure that
          > > > > you have a good 50 ohm termination.
          > > > >
          > > > > Regards,
          > > > >
          > > > > John g0orx/n6lyt
          > > >
          > > >
          > >
          > >
          > > --
          > > --
          > > John Melton
          > > Sun IT CTO
          > > Office: +44 1252 421708 (ext 21708)
          > > Mobile: +44 7714 708861
          > >
          >
          >


          --
          --
          John Melton
          Sun IT CTO
          Office: +44 1252 421708 (ext 21708)
          Mobile: +44 7714 708861
        • datosa2001
          John, I have idea to design I/Q generator with 2 AD9951 or AD9954 to avoid the X4 factor, I have some doubt about the internal AD9954 comparator, did you
          Message 4 of 14 , Jul 4, 2006
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            John,
            I have idea to design I/Q generator with 2 AD9951 or AD9954 to avoid
            the X4 factor, I have some doubt about the internal AD9954
            comparator, did you already try that one? any advantage?

            Davide

            --- In softrock40@yahoogroups.com, John Melton <john.melton@...>
            wrote:
            >
            > The 50 ohm termination does help somewhat and, yes, it is before
            the
            > 47pf cap. There are still frequencies where there are many spurs
            across
            > the 48/96 KHz bandwidth but you can easily offset the DDS-60 to a
            > frequency that has none or minimal spurs and use the software to
            tune
            > the required frequency.
            >
            > I have been experimenting with some code for a version of my Java
            GUI
            > for DttSP that is similar to the spur reduction code in PowerSDR
            but
            > modified for the AD9951. I plan on making that code part of the
            release
            > for DttSP2.
            >
            > John
            >
            > n3hkn wrote On 07/04/06 14:41,:
            >
            > > John,
            > > You seem to have a lot of experience with the DDS60 as a VFO
            driving
            > > the SoftRock series. My experience has been with the V5 where I
            found
            > > the amount of spurs in the bandpass to be high (amount) enough to
            set
            > > the DDS60 aside as a VFO. Do you find the number and amplitude of
            the
            > > spurs excessive (used as a VFO) in your experience?
            > >
            > > The one thing I did not do was to put 50ohms across the DDS60. I
            would
            > > guess that the resistor should be placed before the 47pf cap??
            > >
            > > Dick N3HKN
            > >
            > > --- In softrock40@yahoogroups.com
            > > <mailto:softrock40%40yahoogroups.com>, John Melton <john.melton@>
            > > wrote:
            > > >
            > > > Hi Ben,
            > > >
            > > > In all cases I have not populated Xtal/2n3904 oscillator
            circuit and I
            > > > have also put a 50 ohm termination across the input from the
            DDS-60.
            > > >
            > > > V4 - DDS-60 input to C8.
            > > > V5 - DDS-60 input to pin 4 of J1 on QSD board with 47pF cap in
            series.
            > > > V6 - DDS-60 input to C7
            > > > V7 - DDS-60 input to C6
            > > >
            > > > Hope that helps,
            > > >
            > > > Regards,
            > > >
            > > > John g0orx/n6lyt
            > > >
            > > > Ben Hall wrote On 07/03/06 23:12,:
            > > >
            > > > > Hi John,
            > > > >
            > > > > How/where do you connect the DDS-60 to your various versions
            of the
            > > > > softrock?
            > > > >
            > > > > thanks and 73,
            > > > > ben, KD5BYB
            > > > >
            > > > > John Melton wrote:
            > > > > > I have a DDS-60 from AMQRP
            > > > > http://www.amqrp.org/kits/dds60/index.html
            > > <http://www.amqrp.org/kits/dds60/index.html>
            > > > > <http://www.amqrp.org/kits/dds60/index.html
            > > <http://www.amqrp.org/kits/dds60/index.html>>
            > > > > > <http://www.amqrp.org/kits/dds60/index.html
            > > <http://www.amqrp.org/kits/dds60/index.html>
            > > > > <http://www.amqrp.org/kits/dds60/index.html
            > > <http://www.amqrp.org/kits/dds60/index.html>>>
            > > > > > that I use with several different versions of the SoftRock.
            > > Apart from
            > > > > > some spurs, which can be avoided, it works well. Just make
            sure that
            > > > > > you have a good 50 ohm termination.
            > > > > >
            > > > > > Regards,
            > > > > >
            > > > > > John g0orx/n6lyt
            > > > >
            > > > >
            > > >
            > > >
            > > > --
            > > > --
            > > > John Melton
            > > > Sun IT CTO
            > > > Office: +44 1252 421708 (ext 21708)
            > > > Mobile: +44 7714 708861
            > > >
            > >
            > >
            >
            >
            > --
            > --
            > John Melton
            > Sun IT CTO
            > Office: +44 1252 421708 (ext 21708)
            > Mobile: +44 7714 708861
            >
          • n3hkn
            The first low value resistor I came across was 42 ohms so installed that across the DDS60 output. The spur population is now much less. I do not think that you
            Message 5 of 14 , Jul 5, 2006
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              The first low value resistor I came across was 42 ohms so installed
              that across the DDS60 output. The spur population is now much less.
              I do not think that you could ever simply set your SDR at a place in
              the 48/96khz bandwidth and simply tune the DD60 as you would
              a "normal" VFO. While the spurs are less numerous, such tuning
              produces constant low level audible birdies that could be signals
              (perhaps CW).

              However, as John noted, you can select a region of a band (48 or
              96khz) and tune the DDS to produce minimum/acceptable spurs. Then
              tune as you would if the SDR was xtal controlled. As an example if
              you were interested in PSK you can easily find a setting with spur
              free operation in the 14.070 area. The same for CW (more 48/96khz
              segments) or SSB (many more 48khz/96khz segments). However, for SSB
              some software has notch filtering which allows more general tuning
              with good results even if a spur is setting within the selected
              passband.

              Dick N3HKN



              --- In softrock40@yahoogroups.com, John Melton <john.melton@...>
              wrote:
              >
              > The 50 ohm termination does help somewhat and, yes, it is before
              the
              > 47pf cap. There are still frequencies where there are many spurs
              across
              > the 48/96 KHz bandwidth but you can easily offset the DDS-60 to a
              > frequency that has none or minimal spurs and use the software to
              tune
              > the required frequency.
              >
              > I have been experimenting with some code for a version of my Java
              GUI
              > for DttSP that is similar to the spur reduction code in PowerSDR
              but
              > modified for the AD9951. I plan on making that code part of the
              release
              > for DttSP2.
              >
              > John
              >
              > n3hkn wrote On 07/04/06 14:41,:
              >
              > > John,
              > > You seem to have a lot of experience with the DDS60 as a VFO
              driving
              > > the SoftRock series. My experience has been with the V5 where I
              found
              > > the amount of spurs in the bandpass to be high (amount) enough
              to set
              > > the DDS60 aside as a VFO. Do you find the number and amplitude
              of the
              > > spurs excessive (used as a VFO) in your experience?
              > >
              > > The one thing I did not do was to put 50ohms across the DDS60. I
              would
              > > guess that the resistor should be placed before the 47pf cap??
              > >
              > > Dick N3HKN
              > >
              > > --- In softrock40@yahoogroups.com
              > > <mailto:softrock40%40yahoogroups.com>, John Melton
              <john.melton@>
              > > wrote:
              > > >
              > > > Hi Ben,
              > > >
              > > > In all cases I have not populated Xtal/2n3904 oscillator
              circuit and I
              > > > have also put a 50 ohm termination across the input from the
              DDS-60.
              > > >
              > > > V4 - DDS-60 input to C8.
              > > > V5 - DDS-60 input to pin 4 of J1 on QSD board with 47pF cap in
              series.
              > > > V6 - DDS-60 input to C7
              > > > V7 - DDS-60 input to C6
              > > >
              > > > Hope that helps,
              > > >
              > > > Regards,
              > > >
              > > > John g0orx/n6lyt
              > > >
              > > > Ben Hall wrote On 07/03/06 23:12,:
              > > >
              > > > > Hi John,
              > > > >
              > > > > How/where do you connect the DDS-60 to your various versions
              of the
              > > > > softrock?
              > > > >
              > > > > thanks and 73,
              > > > > ben, KD5BYB
              > > > >
              > > > > John Melton wrote:
              > > > > > I have a DDS-60 from AMQRP
              > > > > http://www.amqrp.org/kits/dds60/index.html
              > > <http://www.amqrp.org/kits/dds60/index.html>
              > > > > <http://www.amqrp.org/kits/dds60/index.html
              > > <http://www.amqrp.org/kits/dds60/index.html>>
              > > > > > <http://www.amqrp.org/kits/dds60/index.html
              > > <http://www.amqrp.org/kits/dds60/index.html>
              > > > > <http://www.amqrp.org/kits/dds60/index.html
              > > <http://www.amqrp.org/kits/dds60/index.html>>>
              > > > > > that I use with several different versions of the SoftRock.
              > > Apart from
              > > > > > some spurs, which can be avoided, it works well. Just make
              sure that
              > > > > > you have a good 50 ohm termination.
              > > > > >
              > > > > > Regards,
              > > > > >
              > > > > > John g0orx/n6lyt
              > > > >
              > > > >
              > > >
              > > >
              > > > --
              > > > --
              > > > John Melton
              > > > Sun IT CTO
              > > > Office: +44 1252 421708 (ext 21708)
              > > > Mobile: +44 7714 708861
              > > >
              > >
              > >
              >
              >
              > --
              > --
              > John Melton
              > Sun IT CTO
              > Office: +44 1252 421708 (ext 21708)
              > Mobile: +44 7714 708861
              >
            • gack.brkkarter
              Hi all, A quick update for the new users with V6.2 RX/TX: Depopulate the Xtal/2n3904 oscillator circuit and interface the DDS-60 input to C45, use the
              Message 6 of 14 , Dec 15, 2007
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                Hi all,

                A quick update for the new users with V6.2 RX/TX:

                Depopulate the Xtal/2n3904 oscillator circuit and interface the DDS-60
                input to C45, use the unpopulated emitter solder point for Q13.

                Todd
                KV1M

                --- In softrock40@yahoogroups.com, John Melton <john.melton@...> wrote:
                >
                > Hi Ben,
                >
                > In all cases I have not populated Xtal/2n3904 oscillator circuit and I
                > have also put a 50 ohm termination across the input from the DDS-60.
                >
                > V4 - DDS-60 input to C8.
                > V5 - DDS-60 input to pin 4 of J1 on QSD board with 47pF cap in series.
                > V6 - DDS-60 input to C7
                > V7 - DDS-60 input to C6
                >
                > Hope that helps,
                >
                > Regards,
                >
                > John g0orx/n6lyt
                >
                > Ben Hall wrote On 07/03/06 23:12,:
                >
                > > Hi John,
                > >
                > > How/where do you connect the DDS-60 to your various versions of the
                > > softrock?
                > >
                > > thanks and 73,
                > > ben, KD5BYB
                > >
                > > John Melton wrote:
                > > > I have a DDS-60 from AMQRP
                > > http://www.amqrp.org/kits/dds60/index.html
                > > <http://www.amqrp.org/kits/dds60/index.html>
                > > > <http://www.amqrp.org/kits/dds60/index.html
                > > <http://www.amqrp.org/kits/dds60/index.html>>
                > > > that I use with several different versions of the SoftRock.
                Apart from
                > > > some spurs, which can be avoided, it works well. Just make sure that
                > > > you have a good 50 ohm termination.
                > > >
                > > > Regards,
                > > >
                > > > John g0orx/n6lyt
                > >
                > >
                >
                >
                > --
                > --
                > John Melton
                > Sun IT CTO
                > Office: +44 1252 421708 (ext 21708)
                > Mobile: +44 7714 708861
                >
              • Alan
                ... From: gack.brkkarter ... What I have done is remove JP2 and JP1. Then a DDS60 (or whatever) can be connected to the centre pin of JP1. Quick and simple
                Message 7 of 14 , Dec 16, 2007
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                  ----- Original Message -----
                  From: "gack.brkkarter"
                  >
                  > Depopulate the Xtal/2n3904 oscillator circuit and interface the DDS-60
                  > input to C45, use the unpopulated emitter solder point for Q13.

                  What I have done is remove JP2 and JP1.
                  Then a DDS60 (or whatever) can be connected to the centre pin of JP1.
                  Quick and simple to revert to the crystals.

                  73 Alan G4ZFQ
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