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Fw: [softrock40] Re: DDS-60 and Softrock V5 - Spurs

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  • windy10605@juno.com
    Can you, N3HKN, describe what you see relative to the DDS spurs ? Is that across the whole 20m ? qty 10 20dB spurs at frequency x-y, no spurs between frequency
    Message 1 of 1 , Feb 27, 2006
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      Can you, N3HKN, describe what you see relative to the DDS spurs ? Is that across the whole 20m ? qty 10 20dB spurs at frequency x-y, no spurs between frequency a-b, etc. Just a rough idea if what you are dealing with.
       
      73 Kees K5BCQ
       
       
      ----- Forwarded Message -----
      From: "mikezingman" <mikezingman@...>
      Date: Tue, 28 Feb 2006 03:39:05 -0000
      Subject: [softrock40] Re: DDS-60 and Softrock V5 - Spurs
       
      Dick,

      I measure 0.8v P-P on my 20 meter BPF board, so I suspect that you
      should be able to drive it with the DDS-60.  I am in the process of
      doing exactly the same thing as soon as I build up a new BPF minus the
      OSC.

      As far as the spurs, quite a lot has been done based on the
      information in the Analog Devices white papers on the subject and then
      translated into code by Bob, N4HY.  Refer to section 4 in this link:
      <
      http://www.analog.com/UploadedFiles/Tutorials/450968421DDS_Tutorial_rev12-2-99.pdf
      >


      Mike N4IRR


      --- In softrock40@yahoogroups.com, "n3hkn" <n3hkn@...> wrote:
      >
      > I also posted on QRP-L...
      >
      > I have my
      PIC-EL/DDS-60 as a VFO for my 20 meter V5 QSD. Works well
      > except for the
      spurs. I run the V5 from a small battery to eliminate
      > any pasty path
      that way. However, on some frequencies no spurs in a
      > 48khz bandpass
      while on others total spurs end-to-end. Mostly I can
      > position a station
      between spurs but this is a bit awkward.
      >
      > So, I know that there
      has been discussion on the spurs issues. Has
      > anyone come up with some
      solutions that reduced the number/amplitude
      > of the spurs? As an example,
      does putting either the PIC-EL or the
      > Softrock V5 in a case do any
      good?? DDS-60 connected to Pin-4 of the
      > header via 6 inches of RG-174.
      No components on the OSC/BPF board are
      > connected to Pin-4. Ground to
      Pin-7.
      >
      > One other issue is that the max I can get from the
      DDS-60 is 2V P-P.
      > Is this enough?
      >
      > Thanks-Dick
      Boley  N3HKN
      >




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