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Re: Frequency Drift with Softrock Lite II IF & FT-950

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  • g8voip
    Hi Bill, I do not know the spec for the crystal used in the LiteII RX, but they are nothing special, but probably no better than 20 to 30ppm / deg C, could be
    Message 1 of 7 , Nov 1, 2010
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      Hi Bill,

      I do not know the spec for the crystal used in the LiteII RX, but they are nothing special, but probably no better than 20 to 30ppm / deg C, could be as bad as 50 ppm.

      With the sub-harmonic sampling, maths is not my strong point :), but 60Hz drift / error at 14MHz, equates to approximately 80Hz drift in the 18MHz oscillator, or around 4 ppm. Pretty good for a free running oscillator using a cheap off the shelf crystal.

      73, Bob G8VOI

      --- In softrock40@yahoogroups.com, Bill Richarz <billn4dh@...> wrote:
      >
      > The radio itself does not drift.  If it's tuned to 14.300 when I turn it on and listen to the MM net, it's right on and stays there.  The PowerSDR frequency readout starts out around 60 Hz higher.  After around 30 minutes I have to set the PowerSDR frequency to match the FT-950 readout.
      >
      > Puzzling to say the least.
      >
      > Bill, N4DH
      >
      > --- On Mon, 11/1/10, Alan <alan4alan@...> wrote:
      >
      > From: Alan <alan4alan@...>
      > Subject: Re: [softrock40] Frequency Drift with Softrock Lite II IF & FT-950
      > To: softrock40@yahoogroups.com
      > Date: Monday, November 1, 2010, 2:55 PM
      >
      >
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      >  
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      >
      > ----- Original Message -----
      >
      > From: "Bill Richarz"
      >
      > Subject: [softrock40] Frequency Drift with Softrock Lite II IF & FT-950
      >
      >
      >
      > > Whenever I first turn one my FT-950 and apply voltage to the Softrock Lite
      >
      > > II IF board, the PowerSDR reads about 60Hz higher going through the
      >
      > > PowerSDR software than the VFO readout on the radio. I did all the
      >
      > > calibrations using WWV 30 minutes after "warm up". I have tried turning
      >
      > > on the Softrock Lite II IF on 30 minutes before turning the FT-950 on.
      >
      > > Question is, what is drifting here? The radio, IF in the radio, the
      >
      > > Softrock Lite II board, or something having to do with the software?
      >
      > >
      >
      >
      >
      > Does the radio drift on its own? You need to check this first. It should
      >
      > stay zero beat on WWV.
      >
      > It is also possible the Softrock can drift but eliminate the radio first.
      >
      >
      >
      > 73 Alan G4ZFQ
      >
    • Bill Richarz
      Thanks Bob, Knew it was still pretty small.  It s really not a big deal.  Only when I click on a signal and the radio and SDR does not match for first 30
      Message 2 of 7 , Nov 1, 2010
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        Thanks Bob,

        Knew it was still pretty small.  It's really not a big deal.  Only when I click on a signal and the radio and SDR does not match for first 30 minutes.  I listen to audio from radio anyway.  Just curious what was drifting.

        73 de Bill, N4DH

        --- On Mon, 11/1/10, g8voip <g8voi.reeves59@...> wrote:

        From: g8voip <g8voi.reeves59@...>
        Subject: [softrock40] Re: Frequency Drift with Softrock Lite II IF & FT-950
        To: softrock40@yahoogroups.com
        Date: Monday, November 1, 2010, 4:04 PM

         

        Hi Bill,

        I do not know the spec for the crystal used in the LiteII RX, but they are nothing special, but probably no better than 20 to 30ppm / deg C, could be as bad as 50 ppm.

        With the sub-harmonic sampling, maths is not my strong point :), but 60Hz drift / error at 14MHz, equates to approximately 80Hz drift in the 18MHz oscillator, or around 4 ppm. Pretty good for a free running oscillator using a cheap off the shelf crystal.

        73, Bob G8VOI

        --- In softrock40@yahoogroups.com, Bill Richarz <billn4dh@...> wrote:
        >
        > The radio itself does not drift.  If it's tuned to 14.300 when I turn it on and listen to the MM net, it's right on and stays there.  The PowerSDR frequency readout starts out around 60 Hz higher.  After around 30 minutes I have to set the PowerSDR frequency to match the FT-950 readout.
        >
        > Puzzling to say the least.
        >
        > Bill, N4DH
        >
        > --- On Mon, 11/1/10, Alan <alan4alan@...> wrote:
        >
        > From: Alan <alan4alan@...>
        > Subject: Re: [softrock40] Frequency Drift with Softrock Lite II IF & FT-950
        > To: softrock40@yahoogroups.com
        > Date: Monday, November 1, 2010, 2:55 PM
        >
        >
        >
        >
        >
        >
        >
        >  
        >
        >
        >
        >
        >
        >
        >
        >
        >
        >
        >
        > ----- Original Message -----
        >
        > From: "Bill Richarz"
        >
        > Subject: [softrock40] Frequency Drift with Softrock Lite II IF & FT-950
        >
        >
        >
        > > Whenever I first turn one my FT-950 and apply voltage to the Softrock Lite
        >
        > > II IF board, the PowerSDR reads about 60Hz higher going through the
        >
        > > PowerSDR software than the VFO readout on the radio. I did all the
        >
        > > calibrations using WWV 30 minutes after "warm up". I have tried turning
        >
        > > on the Softrock Lite II IF on 30 minutes before turning the FT-950 on.
        >
        > > Question is, what is drifting here? The radio, IF in the radio, the
        >
        > > Softrock Lite II board, or something having to do with the software?
        >
        > >
        >
        >
        >
        > Does the radio drift on its own? You need to check this first. It should
        >
        > stay zero beat on WWV.
        >
        > It is also possible the Softrock can drift but eliminate the radio first.
        >
        >
        >
        > 73 Alan G4ZFQ
        >


      • Pat
        I use a lite II with my TS-940 and found that it drifts a bit. I eliminated the rig fairly early in my investigations. Unfortunately, I haven t had enough
        Message 3 of 7 , Nov 1, 2010
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          I use a lite II with my TS-940 and found that it drifts a bit. I eliminated the rig fairly early in my investigations. Unfortunately, I haven't had enough time to finish up what I was doing. In the interim, I use WWV and readjust the IF offset in PowerSDR-IF when I start operating. This works for me.

          Pat
          WB2GBF
        • Clive Jenner
          I would think that if your within 60Hz of a frequency on switch on with any item of frequency determining equipment, then that would be good enough for
          Message 4 of 7 , Nov 2, 2010
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            I would think that if your within 60Hz of a frequency on switch on with
            any item of frequency determining equipment, then that would be good
            enough for science!

            It's good practice to let equipment have a chance to reach thermal
            equilibrium., before you wish to use it.

            73 Clive GW0PPO
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