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Re: [softrock40] SoftRock V6 with AD9951

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  • John Melton
    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 -
    Message 1 of 14 , Jul 4, 2006
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      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
    • Ben Hall
      Hi John and group, Crystal clear! (pun not intended, but I guess its a little funny) thanks and 73, ben, KD5BYB
      Message 2 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 3 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 4 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 5 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 6 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 7 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 8 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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