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Re: [softrock40] 40dBm IP3-Mixer

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  • Marco IK1ODO -2
    ... Ed Oxner, KB6QJ, was a designer of Siliconix in the 70 and 80 . A quick search on the web retrieves an interesting patent (by Dobrovolny) referring to his
    Message 1 of 13 , Apr 1, 2007
      At 16.44 01/04/2007, you wrote:


      >Any one remember Ed Oxners articles about 4 FETs in a ring, back in the
      >70's if I remember right.
      >I've probably misspelt the guys name..sorry
      >
      >Richard

      Ed Oxner, KB6QJ, was a designer of Siliconix in the 70' and 80'. A
      quick search on the web retrieves an interesting patent (by
      Dobrovolny) referring to his work, for a quad-GaAsFET mixer: - it's
      #5280648 . Worth studying... also check #5027163.

      There was an article by Ed Oxner on Ham Radio, in 1988, about FET
      ring mixers. Anyone has a PDF copy?

      73 - Marco IK1ODO
    • Bill Dumke
      Another thing that helps a lot is to terminate the mixer s IF port in a short circuit everywhere outside the IF passband. This is easy with a narrowband IF.
      Message 2 of 13 , Apr 1, 2007
        Another thing that helps a lot is to terminate the mixer's IF port in a
        short circuit everywhere outside the IF passband. This is easy with a
        narrowband IF. If the first IF filter looks like an open circuit
        outside the passband, use an impedance inverter. Voila! A short circuit.

        If the mixer port sees a high impedance outside of the passband on the
        IF port, it will have more gain, or less loss, than it does in the
        passband. And the 3rd order intermod will be worse.

        Diode mixers are bad for a number of reasons, but terminating them in 50
        Ohms doesn't help any. Active mixers properly biased work a lot better
        than diode mixers, because you can get lower noise figures with some
        gain instead of just loss. And if you bias a good RF power FET with
        the right LO voltage swing, etc. you can get great intermod performance
        as well.

        This thing uses FETs, not diodes.

        See patents under Franklin J. Cerny, Motorola. Worked with him in the
        early 70's.

        Bill wa9pwr

        Marco IK1ODO -2 wrote:
        >
        > At 16.44 01/04/2007, you wrote:
        >
        > >Any one remember Ed Oxners articles about 4 FETs in a ring, back in the
        > >70's if I remember right.
        > >I've probably misspelt the guys name..sorry
        > >
        > >Richard
        >
        > Ed Oxner, KB6QJ, was a designer of Siliconix in the 70' and 80'. A
        > quick search on the web retrieves an interesting patent (by
        > Dobrovolny) referring to his work, for a quad-GaAsFET mixer: - it's
        > #5280648 . Worth studying... also check #5027163.
        >
        > There was an article by Ed Oxner on Ham Radio, in 1988, about FET
        > ring mixers. Anyone has a PDF copy?
        >
        > 73 - Marco IK1ODO
        >
        >
      • tom_iphi
        Thanks Guido, that s interesting. I didn t find a schematic on their webpage. So it s a single balanced FET mixer. Simple enough. 73, Tom DG8SAQ ... 10Watts
        Message 3 of 13 , Apr 1, 2007
          Thanks Guido,

          that's interesting. I didn't find a schematic on their webpage.
          So it's a single balanced FET mixer. Simple enough.

          73, Tom DG8SAQ

          --- In softrock40@yahoogroups.com, Guido <threeme3@...> wrote:
          >
          > Hello Tom,
          >
          > While ago I read this about something comparable:
          >
          > http://phenix.rootshell.be/~pe1nnz/ne3508.jpg
          >
          > 73, Guido
          >
          > On 4/1/07, tom_iphi <iphi@...> wrote:
          >
          > > I have stumbled across this very impressive HF mixer:
          > > What's the trick to achieve such a high IP3 without running a
          10Watts
          > > LO?
          > >
          >
        • Guido
          Hello, Yes, and you know I was really surprised to see that the softrock v7 is actually a setup in a similar configuration as is in the schematic and like
          Message 4 of 13 , Apr 2, 2007
            Hello,

            Yes, and you know I was really surprised to see that the softrock v7 is actually a setup in a similar configuration as is in the schematic and like patent 5280648.  ...or is this thought too simple?

            Guido

            On 4/2/07, tom_iphi <iphi@...> wrote:
            Thanks Guido,

            that's interesting. I didn't find a schematic on their webpage.
            So it's a single balanced FET mixer. Simple enough.

            73, Tom DG8SAQ

            --- In softrock40@yahoogroups.com, Guido <threeme3@...> wrote:
            >
            > Hello Tom,
            >
            > While ago I read this about something comparable:
            >
            >     http://phenix.rootshell.be/~pe1nnz/ne3508.jpg
            >
            > 73, Guido
            >
            > On 4/1/07, tom_iphi <iphi@...> wrote:
            >
            > > I have stumbled across this very impressive HF mixer:
            > > What's the trick to achieve such a high IP3 without running a
            10Watts
            > > LO?

          • Guido
            Hello, Yes, and you know I was really surprised to see that the softrock v7 is actually a setup in a similar configuration as is in the schematic and like
            Message 5 of 13 , Apr 2, 2007
              Hello,

              Yes, and you know I was really surprised to see that the softrock v7 is actually a setup in a similar configuration as is in the schematic and like patent 5280648.  ...or is this thought too simple?

              Guido


              On 4/2/07, tom_iphi < iphi@...> wrote:
              Thanks Guido,

              that's interesting. I didn't find a schematic on their webpage.
              So it's a single balanced FET mixer. Simple enough.

              73, Tom DG8SAQ

              --- In softrock40@yahoogroups.com, Guido <threeme3@...> wrote:
              >
              > Hello Tom,
              >
              > While ago I read this about something comparable:
              >
              >     http://phenix.rootshell.be/~pe1nnz/ne3508.jpg
              >
              > 73, Guido
              >
              > On 4/1/07, tom_iphi <iphi@...> wrote:
              >
              > > I have stumbled across this very impressive HF mixer:
              > > What's the trick to achieve such a high IP3 without running a
              10Watts
              > > LO?

            • tom_iphi
              Hello, I take it back! That s no single balanced mixer at all! Not SoftRock like. The RF does obviously NOT pass thru the FETs. The FETs somehow serve as
              Message 6 of 13 , Apr 2, 2007
                Hello,

                I take it back! That's no single balanced mixer at all! Not SoftRock
                like. The RF does obviously NOT pass thru the FETs. The FETs somehow
                serve as switchable wave-reflectors, but I haven't fully grasped the
                function yet.
                RF and IF are connected at a single point, call it P. If the baluns
                weren't there it would just be a linear circuit without mixing
                action. Thus the baluns + FETs must serve as a switchable impedance
                also connected at point P. If switched with the LO we get mixing.

                Does anybody have an idea why the left part with FETs and baluns
                looks like it looks?

                73, Tom DG8SAQ

                --- In softrock40@yahoogroups.com, Guido <threeme3@...> wrote:
                >
                > Hello,
                >
                > Yes, and you know I was really surprised to see that the softrock
                v7 is
                > actually a setup in a similar configuration as is in the schematic
                and like
                > patent 5280648. ...or is this thought too simple?
                >
                > Guido
                >
                > On 4/2/07, tom_iphi <iphi@...> wrote:
                > >
                > > Thanks Guido,
                > >
                > > that's interesting. I didn't find a schematic on their webpage.
                > > So it's a single balanced FET mixer. Simple enough.
                > >
                > > 73, Tom DG8SAQ
                > >
                > > --- In softrock40@yahoogroups.com, Guido <threeme3@> wrote:
                > > >
                > > > Hello Tom,
                > > >
                > > > While ago I read this about something comparable:
                > > >
                > > > http://phenix.rootshell.be/~pe1nnz/ne3508.jpg
                > > >
                > > > 73, Guido
                > > >
                > > > On 4/1/07, tom_iphi <iphi@> wrote:
                > > >
                > > > > I have stumbled across this very impressive HF mixer:
                > > > > What's the trick to achieve such a high IP3 without running a
                > > 10Watts
                > > > > LO?
                > >
                >
              • Giancarlo
                Hi Guido, the SoftRock V7 is not derived from the patented mixer . It is derived from a I-Q mixer I proposed in 2004 and it was published in RadCom in the
                Message 7 of 13 , Apr 4, 2007
                  Hi Guido,

                  the SoftRock V7 is not derived from the "patented mixer".

                  It is derived from a I-Q mixer I proposed in 2004 and it was
                  published in RadCom in the G3VA column Technical Topics. I will
                  upload the circuit diagram. You will see two I7SWX 1T Double balanced
                  mixer drveng by a digital quadrature generator. The circuit has two
                  separate transformers that could have been driven by a combiner.
                  The V7 was taken from such circuit but using a single transformer and
                  in place of the FST3125 Phil, VK6APH, used the FST3253 multipler as
                  used in the V6 version.
                  As the Synergy datasheet is publishe in 2006 ... maybe they took the
                  idea from 2004 ... hi hi hi !!!
                  The same circuit was also publishe in Radio Rivista in 2004

                  73

                  Gian
                  I7SWX

                  --- In softrock40@yahoogroups.com, Guido <threeme3@...> wrote:
                  >
                  > Hello,
                  >
                  > Yes, and you know I was really surprised to see that the softrock
                  v7 is
                  > actually a setup in a similar configuration as is in the schematic
                  and like
                  > patent 5280648. ...or is this thought too simple?
                  >
                  > Guido
                  >
                  > On 4/2/07, tom_iphi <iphi@...> wrote:
                  > >
                  > > Thanks Guido,
                  > >
                  > > that's interesting. I didn't find a schematic on their webpage.
                  > > So it's a single balanced FET mixer. Simple enough.
                  > >
                  > > 73, Tom DG8SAQ
                  > >
                  > > --- In softrock40@yahoogroups.com, Guido <threeme3@> wrote:
                  > > >
                  > > > Hello Tom,
                  > > >
                  > > > While ago I read this about something comparable:
                  > > >
                  > > > http://phenix.rootshell.be/~pe1nnz/ne3508.jpg
                  > > >
                  > > > 73, Guido
                  > > >
                  > > > On 4/1/07, tom_iphi <iphi@> wrote:
                  > > >
                  > > > > I have stumbled across this very impressive HF mixer:
                  > > > > What's the trick to achieve such a high IP3 without running a
                  > > 10Watts
                  > > > > LO?
                  > >
                  >
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