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Re: FT1000 MK5 Field / Icom radio IF panadapter.

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  • ccmarco2004
    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
    Message 1 of 9 , Jun 1, 2006
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      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).

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

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

      Am i wrong in some way ?

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

      Saluti, Marco.




      --- In softrock40@yahoogroups.com, "Giancarlo" <i7swx@...> wrote:
      >
      > --- In softrock40@yahoogroups.com, "ccmarco2004" <ccmarco@> wrote:
      > >
      > > Hi to all,
      > > i'm new of this group, i'm awaiting for two, just ordered,
      > SoftRock
      > > kit, one v6.0 and one v7.0.
      > >
      > > I was wondering if someone could give me any tip regarding the
      use
      > > of these circuits as IF panadapter for the FT-1000 MKV Field
      8.215
      > > MHz IF and Icom's 9.015 Mhz IF.
      > >
      > > My intent is to modify circuits input filters, shift network
      (for
      > > v7.0)and Xtals to obtain proper tuning on center IF freq.
      > >
      > > Maybe could be also good to use an IF input preamplifier to feed
      > > SoftRock input to avoid IF chains loading.
      > >
      > > For Yaesu seems fine to use 8.192 MHz Xtal with SR v7.0 as seems
      > > fine to use 9 MHz Xtal for Icom.
      > >
      > > I could be good also to use 36 MHz Xtal with SR v6.0 with 4x
      > setting.
      > >
      > > Has anyone already done something like that ?
      > >
      > > Thanks in advance.
      > >
      > > Marco, IW2NYX.
      > >
      >
      > Hi Marco,
      >
      > my comments to your question are only "suggestions" as I have not
      > tried anything.
      >
      > As you said you will have to change the xtal for the proper
      receiver
      > IF selected. For SR V7 you will need a xtal cut for the yaesu
      8.192
      > or icom 9.0+ IF; for this you will have to adjust the phasing
      > capacitor's value. For the SR V6 you will need a xtal IF x 4.
      >
      > I suggest you not to have any filter at the SR input.
      >
      > For the Yaesu FT1000MK you should attach the SR at the secondary
      of
      > T2001 in the Noise Blanker IF amplifier. If not enough output to
      > drive the SR you can attach it to T2002 secondary output.
      > I do not know what is the impedance at these points. While
      modifying
      > the nd Mixer and 2nd IF in the FT1000MP I "discovered" (measure
      > guessing) some transformers secondaries where around 200 ohm (???).
      >
      > To avoid mismatching problems, you should add a JFET buffer (J310
      or
      > BF245) with a 47 to 100 ohm R and a parallel C of 0.1uF R between
      > the source and the SR input primary transformer (one side of it to
      > gnd).
      >
      > With this solution you will monitor all signals passing througfht
      > the 70 MHz 1st IF roofing filter, although being at 8 MHz.
      >
      > Regarding ICOM transceivers I do not know which model you are
      > thinking of. The IC756, IC775 and IC765 are quite similar at the
      2nd
      > conversion. You may try to connect the SR, with input JFET buffer
      > connected at the 2nd IF roofing filter FL23. If not enough gain
      then
      > you may replace the JFET buffer with a DGM cascode amplifier or
      have
      > a grounded gate JFET ampolifier following the JFET buffer and
      > driving the SoftRock.
      >
      > These are ideas that may work right away ... please post any "try
      > and buy" you may experiment.
      >
      > For additional discussions in Italian you can send me direct mail.
      >
      > 73
      >
      > Gian
      > I7SWX
      >
    • 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 2 of 9 , Jun 1, 2006
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        --- 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 3 of 9 , Jun 2, 2006
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          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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