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Re: FT1000 MK5 Field / Icom radio IF panadapter.

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  • Lyle Koehler, K0LR
    ... The SDR input is in parallel with the used filter. I offset the SDR local oscillator so that the center of the filter passband came out at 13 kHz on the
    Message 1 of 9 , Jun 1, 2006
      --- In softrock40@yahoogroups.com, "ccmarco2004" <ccmarco@...> wrote:
      >
      > Hi Lyle,
      > good news because i also own a IC-706.
      >
      > some questions :
      >
      > - do you feed the SDR by mean of empty filter slot input line ?
      > - or is the SDR input in parallel with the used filter ?
      > - did you notice injected noise to 706 RXed signal when using SDR
      > connection ?
      >

      The SDR input is in parallel with the used filter. I offset the SDR
      local oscillator so that the center of the filter passband came out
      at 13 kHz on the Winrad display. That kept the local oscillator out
      of the passband, and I didn't notice any injected noise. But a FET
      follower is a good idea because it would reduce the loading of the
      IF circuit and would also provide some reverse isolation.

      Lyle, K0LR
    • Giancarlo
      Hi Marco, pse see below ... comparator ... OK. Going lower in frequency you will have a lower effect of group delay. ... this ... Nothing is perfect in this
      Message 2 of 9 , Jun 2, 2006
        Hi Marco,

        pse see below

        --- In softrock40@yahoogroups.com, "ccmarco2004" <ccmarco@...> wrote:
        >
        > Hi Gian,
        >
        > many thanks for detailed FT-1000 IF connection aid.
        >
        > I have just a question about v7.0 schematic :
        >
        > yesterday i was simulating the shifter network for 10 meter band
        > version (R8: 1K, C9 : 10pF), and taking into account the
        comparator
        > propagation delay, 4.2 nS, and input capacitance, 2 pF, i have
        > obtained a total group delay greater than expected (8.86 nS, 90
        > degree @ 28.204 MHz).

        OK. Going lower in frequency you will have a lower effect of group
        delay.

        > I also thinked that could be very difficult trim & fix exactly
        this
        > delay, due to parassitic parameter variance (thermal, aging, etc
        > etc).

        Nothing is perfect in this world ... so you have to compromise ...
        and adapt yourself and the circuit...hi

        > From this aspect, is not much better the v6.0 configuration, with
        > digital divider ?

        Yes

        > Am i wrong in some way ?

        NO

        > Could you quickly explain me performance differences from SR v6.0
        > and v7.0 ?

        I havent done any measurements comparison between the two. The V6
        certainly has a better quadrature generation.

        I am working an a digital quadrature circuit where we have a divide
        by 2 that will make possible to reduce the L.O. frequency
        particularly going up to 28-30MHz band.

        I will keep the group posted ... last night I got a fault on the
        OPA ...one channel went bang !"!! hi

        Going out for lunch with XYL, family and friend to celebrate out
        37th wedding anniversary ...hi

        73

        Gian
        I7SWX
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