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Re: [softrock40] Re: spike on first TX after standby

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  • Alan
    ... Sent: Monday, March 11, 2013 11:18 PM Subject: [softrock40] Re: spike on first TX after standby ... Chris, I see this is a receiver (with great attention
    Message 1 of 19 , Mar 12, 2013
    ----- Original Message -----
    Sent: Monday, March 11, 2013 11:18 PM
    Subject: [softrock40] Re: spike on first TX after standby


    > Hi Alan
    > I put the project on cool for a few days. What is bad is that I can produce this on 3 different units . I also have a 6.2 , and
    > this don't spike ... So
    >
    > A Brazilian ZeroSDR writs in his project that the FTS3253 can spike if the output is not well balanced .

    Chris,

    I see this is a receiver (with great attention to balance) http://py2wm.qsl.br/SDR/SDRZero-2.html and the FST3253 is not switched.
    However I have found that the switching seems to be the cause of the pulse.

    Attached, picture of my test mod. I can revert by moving the jumper.
    The track next to pin 1 cut, the jumper reconnects it or connects 1, 15 directly to ground.
    So far I've seen no spike.
    The possible downside of leaving the mixer live? I do not think there is one, just maybe a little more LO floating around?
    And the reason this only happens on the 6.3? Maybe because there is more unbalance due to the extra tracks/connector for the
    plug-in? Certainly the Ensemble goes very directly to the transformer.

    Spot the missing Si570? It is at the other side of the board wrapped up with a Khune heater.

    73 Alan G4ZFQ
  • MIKE DURKIN
    where and how much is a Khune heater? To: softrock40@yahoogroups.com From: alan4alan@googlemail.com Date: Tue, 12 Mar 2013 16:54:53 +0000 Subject: Re:
    Message 2 of 19 , Mar 12, 2013
    • 0 Attachment
      where and how much is a Khune heater?


      To: softrock40@yahoogroups.com
      From: alan4alan@...
      Date: Tue, 12 Mar 2013 16:54:53 +0000
      Subject: Re: [softrock40] Re: spike on first TX after standby [1 Attachment]

       
      [Attachment(s) from Alan included below]
      ----- Original Message -----
      Sent: Monday, March 11, 2013 11:18 PM
      Subject: [softrock40] Re: spike on first TX after standby

      > Hi Alan
      > I put the project on cool for a few days. What is bad is that I can produce this on 3 different units . I also have a 6.2 , and
      > this don't spike ... So
      >
      > A Brazilian ZeroSDR writs in his project that the FTS3253 can spike if the output is not well balanced .

      Chris,

      I see this is a receiver (with great attention to balance) http://py2wm.qsl.br/SDR/SDRZero-2.html and the FST3253 is not switched.
      However I have found that the switching seems to be the cause of the pulse.

      Attached, picture of my test mod. I can revert by moving the jumper.
      The track next to pin 1 cut, the jumper reconnects it or connects 1, 15 directly to ground.
      So far I've seen no spike.
      The possible downside of leaving the mixer live? I do not think there is one, just maybe a little more LO floating around?
      And the reason this only happens on the 6.3? Maybe because there is more unbalance due to the extra tracks/connector for the
      plug-in? Certainly the Ensemble goes very directly to the transformer.

      Spot the missing Si570? It is at the other side of the board wrapped up with a Khune heater.

      73 Alan G4ZFQ

    • Alan
      ... Subject: RE: [softrock40] Re: spike on first TX after standby ... http://www.kuhne-electronic.de/en/products/crystal-heater.html 13€+ Whether it is worth
      Message 3 of 19 , Mar 12, 2013
      • 0 Attachment
        ----- Original Message -----
        Subject: RE: [softrock40] Re: spike on first TX after standby


        >where and how much is a Khune heater?

        http://www.kuhne-electronic.de/en/products/crystal-heater.html 13€+

        Whether it is worth the price for use with the Si570 I'm not sure.
        I use them on crystals in RXs and they hold things very steady. The drift in the Si570 is reduced, but not so well.
        The one in my Softrock is mounted on a small board with the heater and wrapped up.
        Connected to the Softrock with thin wires.

        73 Alan G4ZFQ
      • chris
        Hi Alan Today the wx put me on cool with a snow chaos :) Thank you for your efforts . I came to same result as you. every time I enable the QSE by grounding
        Message 4 of 19 , Mar 13, 2013
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          Hi Alan

          Today the wx put me on cool with a snow chaos :)
          Thank you for your efforts .

          I came to same result as you. every time I enable the QSE by grounding the collector of Q3 , I get the spike .

          I will try your mods , and see where it take the project . However as you , I am puzzles why my SR6.2 is not spiking , it is same design , but as you writes, shorter leads to the T200.

          What I have don is pulled up R17&18 with each a 47ohm to the tap between R15 and R16. Then I key the PTT IN and measure on the right side of R18 , and I have no spike! BUT I do get a DC dip , that look like a capacitor discharge curve , thinking of C16.
          (the PA module is of cause not plug-in)

          I will test my SR6.2 to see if it has the same DC surge. Could it be a bad batch of FTS 3253 for all of us??

          best vy73 de oz1bxn/chris





          --- In softrock40@yahoogroups.com, "Alan" <alan4alan@...> wrote:
          >
          >
          > ----- Original Message -----
          > Sent: Monday, March 11, 2013 11:18 PM
          > Subject: [softrock40] Re: spike on first TX after standby
          >
          >
          > > Hi Alan
          > > I put the project on cool for a few days. What is bad is that I can produce this on 3 different units . I also have a 6.2 , and
          > > this don't spike ... So
          > >
          > > A Brazilian ZeroSDR writs in his project that the FTS3253 can spike if the output is not well balanced .
          >
          > Chris,
          >
          > I see this is a receiver (with great attention to balance) http://py2wm.qsl.br/SDR/SDRZero-2.html and the FST3253 is not switched.
          > However I have found that the switching seems to be the cause of the pulse.
          >
          > Attached, picture of my test mod. I can revert by moving the jumper.
          > The track next to pin 1 cut, the jumper reconnects it or connects 1, 15 directly to ground.
          > So far I've seen no spike.
          > The possible downside of leaving the mixer live? I do not think there is one, just maybe a little more LO floating around?
          > And the reason this only happens on the 6.3? Maybe because there is more unbalance due to the extra tracks/connector for the
          > plug-in? Certainly the Ensemble goes very directly to the transformer.
          >
          > Spot the missing Si570? It is at the other side of the board wrapped up with a Khune heater.
          >
          > 73 Alan G4ZFQ
          >
        • Alan
          ... Subject: [softrock40] Re: spike on first TX after standby ... Chris, I do not understand the operation of U3 but will the charge across the opamp output
          Message 5 of 19 , Mar 13, 2013
          • 0 Attachment
            ----- Original Message -----
            Subject: [softrock40] Re: spike on first TX after standby


            >
            > I came to same result as you. every time I enable the QSE by grounding the collector of Q3 , I get the spike .
            >
            > I will try your mods , and see where it take the project . However as you , I am puzzles why my SR6.2 is not spiking , it is same
            > design , but as you writes, shorter leads to the T200.
            >
            > What I have don is pulled up R17&18 with each a 47ohm to the tap between R15 and R16. Then I key the PTT IN and measure on the
            > right side of R18 , and I have no spike! BUT I do get a DC dip , that look like a capacitor discharge curve , thinking of C16.
            > (the PA module is of cause not plug-in)
            >
            > I will test my SR6.2 to see if it has the same DC surge. Could it be a bad batch of FTS 3253 for all of us??
            >

            Chris,

            I do not understand the operation of U3 but will the charge across the opamp output capacitors C4, 6, 11, 13 change when it starts
            clocking?
            And, yes also C16. This is biased to about 2V, I wonder why?
            What state are the switches at when not clocking?

            But none of this is different from other Softrocks, well, just C16 is 4u7 in the Ensemble.

            It could be a difference in the FST3253s but only in the 6.3s??

            I have reassembled mine and testing, it seems OK but it would be interesting to know what is the real cause of the spike.
            Possibly this is at LO frequency and caused by a temporary unbalance?? I had at first wondered if it was a sign of instability in
            the amplifiers.

            73 Alan G4ZFQ
          • Jose Bonanca
            There was a problema with the 3253 back some years. it was corrcted, but I think it happened in the 6.2 version. 73 ... -- Jose (Ct1aos)
            Message 6 of 19 , Mar 13, 2013
            • 0 Attachment
              There was a problema with the 3253 back some years. it was corrcted, but I think it happened in the 6.2 version.
              73

              On 13 March 2013 16:26, Alan <alan4alan@...> wrote:
               


              ----- Original Message -----
              Subject: [softrock40] Re: spike on first TX after standby

              >
              > I came to same result as you. every time I enable the QSE by grounding the collector of Q3 , I get the spike .
              >
              > I will try your mods , and see where it take the project . However as you , I am puzzles why my SR6.2 is not spiking , it is same
              > design , but as you writes, shorter leads to the T200.
              >
              > What I have don is pulled up R17&18 with each a 47ohm to the tap between R15 and R16. Then I key the PTT IN and measure on the
              > right side of R18 , and I have no spike! BUT I do get a DC dip , that look like a capacitor discharge curve , thinking of C16.
              > (the PA module is of cause not plug-in)
              >
              > I will test my SR6.2 to see if it has the same DC surge. Could it be a bad batch of FTS 3253 for all of us??
              >

              Chris,

              I do not understand the operation of U3 but will the charge across the opamp output capacitors C4, 6, 11, 13 change when it starts
              clocking?
              And, yes also C16. This is biased to about 2V, I wonder why?
              What state are the switches at when not clocking?

              But none of this is different from other Softrocks, well, just C16 is 4u7 in the Ensemble.

              It could be a difference in the FST3253s but only in the 6.3s??

              I have reassembled mine and testing, it seems OK but it would be interesting to know what is the real cause of the spike.
              Possibly this is at LO frequency and caused by a temporary unbalance?? I had at first wondered if it was a sign of instability in
              the amplifiers.

              73 Alan G4ZFQ




              --
              Jose (Ct1aos)
            • chris
              OK . I really would like to try out a new FST3253. To me it looks like it is leaky . If C4,6,11,13 , just one is low on charge , the spike will occur when
              Message 7 of 19 , Mar 14, 2013
              • 0 Attachment
                OK . I really would like to try out a new FST3253.
                To me it looks like it is "leaky" .
                If C4,6,11,13 , just one is low on charge , the spike will occur when the capacitor is charges true the FST3253 .

                Perhaps a pull-up to the bias of 1A&2A , but again :it should work without mods .

                I am a bit empty other than to try a new chip-



                --- In softrock40@yahoogroups.com, "Alan" <alan4alan@...> wrote:
                >
                >
                > ----- Original Message -----
                > Subject: [softrock40] Re: spike on first TX after standby
                >
                >
                > >
                > > I came to same result as you. every time I enable the QSE by grounding the collector of Q3 , I get the spike .
                > >
                > > I will try your mods , and see where it take the project . However as you , I am puzzles why my SR6.2 is not spiking , it is same
                > > design , but as you writes, shorter leads to the T200.
                > >
                > > What I have don is pulled up R17&18 with each a 47ohm to the tap between R15 and R16. Then I key the PTT IN and measure on the
                > > right side of R18 , and I have no spike! BUT I do get a DC dip , that look like a capacitor discharge curve , thinking of C16.
                > > (the PA module is of cause not plug-in)
                > >
                > > I will test my SR6.2 to see if it has the same DC surge. Could it be a bad batch of FTS 3253 for all of us??
                > >
                >
                > Chris,
                >
                > I do not understand the operation of U3 but will the charge across the opamp output capacitors C4, 6, 11, 13 change when it starts
                > clocking?
                > And, yes also C16. This is biased to about 2V, I wonder why?
                > What state are the switches at when not clocking?
                >
                > But none of this is different from other Softrocks, well, just C16 is 4u7 in the Ensemble.
                >
                > It could be a difference in the FST3253s but only in the 6.3s??
                >
                > I have reassembled mine and testing, it seems OK but it would be interesting to know what is the real cause of the spike.
                > Possibly this is at LO frequency and caused by a temporary unbalance?? I had at first wondered if it was a sign of instability in
                > the amplifiers.
                >
                > 73 Alan G4ZFQ
                >
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