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Fw: Fw: Re: Fw: Re: [softrock40] Re: Bandpass filter smilter

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  • windy10605@juno.com
    You would expect the third harmonic to be the predominant one with no filtering. You are using the DDS-60 for the OSC on the SR-40, right ? set to receive 1Mhz
    Message 1 of 2 , Jan 30, 2006
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      You would expect the third harmonic to be the predominant one with no filtering. You are using the DDS-60 for the OSC on the SR-40, right ? set to receive 1Mhz ?  What are you doing to measure the harmonics ?
       
      73 Kees K5BCQ
       
      ----- Forwarded Message -----
      From: "joe price" <joeprice@...>
      Date: Wed, 01 Feb 2006 23:07:08 -0000
      Subject: Fw: Re: Fw: Re: [softrock40] Re: Bandpass filter smilter
       
      --- In softrock40@yahoogroups.com, windy10605@... wrote:
      >
      > Exactly ! I would much prefer an old tuneable WJ double
      tuned frontend
      > ....but I don't have one, was going to adapt a Drake 2B
      preselector
      > ...haven't done that either, and don't really want to plug
      and replug
      the
      > BPFs as I scoot around the HF spectrum trying other
      things.
      >
      > Looking for the "least undesirable
      alternative".
      >
      > 73 Kees K5BCQ
      >

      Kees,

      I just reconnected my test SD40 setup using DDS as 4x vfo although it
      will hear the even harmonic (way down) it's the odd that is predominate.

      I set DDS to 4mhz for a receive frequency of 1mhz

      2mhz down 45 to 50db

      3mhz down 10db

      5mhz down 12db

      7mhz down 15db

      Joe



    • joe price
      ... no ... right ? set ... Kees, I m using a DDS30 set to 4mhz connected to base of SR40 OSC transistor with feedback caps removed. I have a HP654 generator
      Message 2 of 2 , Feb 1 4:09 PM
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        --- In softrock40@yahoogroups.com, windy10605@... wrote:
        >
        > You would expect the third harmonic to be the predominant one with
        no
        > filtering. You are using the DDS-60 for the OSC on the SR-40,
        right ? set
        > to receive 1Mhz ? What are you doing to measure the harmonics ?
        >
        > 73 Kees K5BCQ
        >

        Kees,

        I'm using a DDS30 set to 4mhz connected to base of SR40 OSC transistor
        with feedback caps removed. I have a HP654 generator with calibrated
        output attenuators. By using one of ROCKY'S DB lines as a reference
        the test generator can be adjusted to the same line and the attenuator
        read as the difference in db.
        Please connect that MiniCiruit transformer and verify my results.

        Joe wa9cgz
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