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Re: spike on first TX after standby

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  • chris
    So funny! I have tested 3 SR63 from 3 different batch , and all make the same spike , so someone else must have the same problem :)
    Message 1 of 19 , Mar 9, 2013
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      So funny! I have tested 3 SR63 from 3 different batch , and all make the same spike , so someone else must have the same problem :)

      --- In softrock40@yahoogroups.com, "chris" <oz1bxn@...> wrote:
      >
      > Well , in my case the SR6.3 produce the spike , even with no input (drive =0) or even without sound cables connected .
      > If I take the SR6.3 , connect only the 12V DC , and PTT using at battery , I can produce the spike .
      > However the funny stuff is that I get a spike on my first PTT keying , When I do #2 , 3 4... I have no spike . If I wait in rx for 2 minute , the spikes shows again! but only on the first PTT keying-
      >
      > --- In softrock40@yahoogroups.com, "alanzfq" <alan4alan@> wrote:
      > >
      > >
      > >
      > > --- In softrock40@yahoogroups.com, "chris" <oz1bxn@> wrote:
      > > >
      > > > I have a funny/serious problem ,
      > > > I switch on my SR6.3. then I start TX (either key down or MOX on PSDR IQ) . Herafter I get an RF spike of 10volts 1mS before normal output .
      > > >
      > > > Has someone else the same problem , and how did it solve?
      > > >
      > >
      > >
      > > Chris
      > >
      > > I have seen this, a long time ago.
      > > I do not remember how I reduced the effect but it was partly due to the way I had setup PSDR.
      > > I reduced the input gain of the Softrock so the soundcard would only just drive to maximum. (But a setting in PSDR compensates for this so this is probably not needed)
      > >
      > > But, I think, more important was that I read the manual and setup PSDR properly.
      > >
      > > 73 Alan G4ZFQ
      > >
      > >
      > > >
      > >
      >
    • John Greusel
      That sounds like a capacitor that s charging and discharging so it doesn t have time to rebound on the 2nd  keying. John KC9OJV  
      Message 2 of 19 , Mar 9, 2013
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        That sounds like a capacitor that's charging and discharging so it doesn't have time to rebound on the 2nd  keying.

        John
        KC9OJV
         



        From: chris <oz1bxn@...>
        To: softrock40@yahoogroups.com
        Sent: Saturday, March 9, 2013 4:54 AM
        Subject: [softrock40] Re: spike on first TX after standby

         
        So funny! I have tested 3 SR63 from 3 different batch , and all make the same spike , so someone else must have the same problem :)

        --- In softrock40@yahoogroups.com, "chris" <oz1bxn@...> wrote:
        >
        > Well , in my case the SR6.3 produce the spike , even with no input (drive =0) or even without sound cables connected .
        > If I take the SR6.3 , connect only the 12V DC , and PTT using at battery , I can produce the spike .
        > However the funny stuff is that I get a spike on my first PTT keying , When I do #2 , 3 4... I have no spike . If I wait in rx for 2 minute , the spikes shows again! but only on the first PTT keying-
        >
        > --- In softrock40@yahoogroups.com, "alanzfq" <alan4alan@> wrote:
        > >
        > >
        > >
        > > --- In softrock40@yahoogroups.com, "chris" <oz1bxn@> wrote:
        > > >
        > > > I have a funny/serious problem ,
        > > > I switch on my SR6.3. then I start TX (either key down or MOX on PSDR IQ) . Herafter I get an RF spike of 10volts 1mS before normal output .
        > > >
        > > > Has someone else the same problem , and how did it solve?
        > > >
        > >
        > >
        > > Chris
        > >
        > > I have seen this, a long time ago.
        > > I do not remember how I reduced the effect but it was partly due to the way I had setup PSDR.
        > > I reduced the input gain of the Softrock so the soundcard would only just drive to maximum. (But a setting in PSDR compensates for this so this is probably not needed)
        > >
        > > But, I think, more important was that I read the manual and setup PSDR properly.
        > >
        > > 73 Alan G4ZFQ
        > >
        > >
        > > >
        > >
        >



      • chris
        That is a very good description , but where to look ? I have the spike before the PA unit , so either switching , amp or mixer?
        Message 3 of 19 , Mar 9, 2013
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          That is a very good description , but where to look ? I have the spike before the PA unit , so either switching , amp or mixer?

          --- In softrock40@yahoogroups.com, John Greusel <greusel@...> wrote:
          >
          > That sounds like a capacitor that's charging and discharging so it doesn't have time to rebound on the 2nd  keying.
          >
          > John
          > KC9OJV
          >  
          >
          >
          >
          > ________________________________
          > From: chris <oz1bxn@...>
          > To: softrock40@yahoogroups.com
          > Sent: Saturday, March 9, 2013 4:54 AM
          > Subject: [softrock40] Re: spike on first TX after standby
          >
          >
          >  
          > So funny! I have tested 3 SR63 from 3 different batch , and all make the same spike , so someone else must have the same problem :)
          >
          > --- In softrock40@yahoogroups.com, "chris" <oz1bxn@> wrote:
          > >
          > > Well , in my case the SR6.3 produce the spike , even with no input (drive =0) or even without sound cables connected .
          > > If I take the SR6.3 , connect only the 12V DC , and PTT using at battery , I can produce the spike .
          > > However the funny stuff is that I get a spike on my first PTT keying , When I do #2 , 3 4... I have no spike . If I wait in rx for 2 minute , the spikes shows again! but only on the first PTT keying-
          > >
          > > --- In softrock40@yahoogroups.com, "alanzfq" <alan4alan@> wrote:
          > > >
          > > >
          > > >
          > > > --- In softrock40@yahoogroups.com, "chris" <oz1bxn@> wrote:
          > > > >
          > > > > I have a funny/serious problem ,
          > > > > I switch on my SR6.3. then I start TX (either key down or MOX on PSDR IQ) . Herafter I get an RF spike of 10volts 1mS before normal output .
          > > > >
          > > > > Has someone else the same problem , and how did it solve?
          > > > >
          > > >
          > > >
          > > > Chris
          > > >
          > > > I have seen this, a long time ago.
          > > > I do not remember how I reduced the effect but it was partly due to the way I had setup PSDR.
          > > > I reduced the input gain of the Softrock so the soundcard would only just drive to maximum. (But a setting in PSDR compensates for this so this is probably not needed)
          > > >
          > > > But, I think, more important was that I read the manual and setup PSDR properly.
          > > >
          > > > 73 Alan G4ZFQ
          > > >
          > > >
          > > > >
          > > >
          > >
          >
        • Alan
          ... Subject: [softrock40] Re: spike on first TX after standby ... Look at the schematic. What switches? Just like the Ensemble, the PA/driver supply with a few
          Message 4 of 19 , Mar 9, 2013
          • 0 Attachment
            ----- Original Message -----
            Subject: [softrock40] Re: spike on first TX after standby


            >but where to look ? I have the spike before the PA unit , so either switching , amp or mixer?

            Look at the schematic. What switches?
            Just like the Ensemble, the PA/driver supply with a few 0.1uFs which would discharge rapidly.
            And the RX mixer switches off.

            I cannot imagine what happens, as I say the 6.3 is almost identical to the Ensemble. Nobody has complained about that.

            I wonder if it is something like a ground loop, the switching surge inducing a pulse into the TX opamps?
            Does it do it with the audio input disconnected?
            Disable the opamps, ground the driver base, try to find a situation that it does not happen.

            73 Alan G4ZFQ
          • MIKE DURKIN
            to me, its an amp that warmed up a bit from the first current draw .. get a can of Freeze it and frost a few components at a time till you find the one that
            Message 5 of 19 , Mar 9, 2013
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              to me, its an amp that warmed up a bit from the first current draw .. get a can of Freeze it and frost a few components at a time till you find the one that breaks into osc .... or cap with poor ESR ... or or or or .....

              Mike ... KC7NOA


              To: softrock40@yahoogroups.com
              From: greusel@...
              Date: Sat, 9 Mar 2013 06:30:31 -0800
              Subject: Re: [softrock40] Re: spike on first TX after standby

               

              That sounds like a capacitor that's charging and discharging so it doesn't have time to rebound on the 2nd  keying.

              John
              KC9OJV
               



              From: chris <oz1bxn@...>
              To: softrock40@yahoogroups.com
              Sent: Saturday, March 9, 2013 4:54 AM
              Subject: [softrock40] Re: spike on first TX after standby

               
              So funny! I have tested 3 SR63 from 3 different batch , and all make the same spike , so someone else must have the same problem :)

              --- In softrock40@yahoogroups.com, "chris" <oz1bxn@...> wrote:
              >
              > Well , in my case the SR6.3 produce the spike , even with no input (drive =0) or even without sound cables connected .
              > If I take the SR6.3 , connect only the 12V DC , and PTT using at battery , I can produce the spike .
              > However the funny stuff is that I get a spike on my first PTT keying , When I do #2 , 3 4... I have no spike . If I wait in rx for 2 minute , the spikes shows again! but only on the first PTT keying-
              >
              > --- In softrock40@yahoogroups.com, "alanzfq" <alan4alan@> wrote:
              > >
              > >
              > >
              > > --- In softrock40@yahoogroups.com, "chris" <oz1bxn@> wrote:
              > > >
              > > > I have a funny/serious problem ,
              > > > I switch on my SR6.3. then I start TX (either key down or MOX on PSDR IQ) . Herafter I get an RF spike of 10volts 1mS before normal output .
              > > >
              > > > Has someone else the same problem , and how did it solve?
              > > >
              > >
              > >
              > > Chris
              > >
              > > I have seen this, a long time ago.
              > > I do not remember how I reduced the effect but it was partly due to the way I had setup PSDR.
              > > I reduced the input gain of the Softrock so the soundcard would only just drive to maximum. (But a setting in PSDR compensates for this so this is probably not needed)
              > >
              > > But, I think, more important was that I read the manual and setup PSDR properly.
              > >
              > > 73 Alan G4ZFQ
              > >
              > >
              > > >
              > >
              >




            • chris
              My problem is that I have tested 3 different SR63 build by 3 different people at 3 different times, and all show same spike . So there must be others out there
              Message 6 of 19 , Mar 9, 2013
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                My problem is that I have tested 3 different SR63 build by 3 different people at 3 different times, and all show same spike .

                So there must be others out there ( just like X-files)

                I have an Xtal SR62, it don't spike . I also try to exclude my setup ( it is same PC and power , dummy and scope ). It is pretty mysterious :-)

                If I had something unintentioned oscillating , I might be able to isolate the problem , but this spike is so killing , especially because I have to wait 2-3 minute to reproduce ( the SR63).

                I will try the chill and see what happen , but your brain storm is appreciated.

                vy73/chris

                --- In softrock40@yahoogroups.com, MIKE DURKIN <Patriot121@...> wrote:
                >
                > to me, its an amp that warmed up a bit from the first current draw .. get a can of Freeze it and frost a few components at a time till you find the one that breaks into osc .... or cap with poor ESR ... or or or or .....
                >
                > Mike ... KC7NOA
                >
                > To: softrock40@yahoogroups.com
                > From: greusel@...
                > Date: Sat, 9 Mar 2013 06:30:31 -0800
                > Subject: Re: [softrock40] Re: spike on first TX after standby
                >
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                > That sounds like a capacitor that's charging and discharging so it doesn't have time to rebound on the 2nd keying.
                > JohnKC9OJV
                >
                > From: chris <oz1bxn@...>
                > To: softrock40@yahoogroups.com
                > Sent: Saturday, March 9, 2013 4:54 AM
                > Subject: [softrock40] Re: spike on first TX after standby
                >
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                > So funny! I have tested 3 SR63 from 3 different batch , and all make the same spike , so someone else must have the same problem :)
                >
                >
                >
                > --- In softrock40@yahoogroups.com, "chris" <oz1bxn@> wrote:
                >
                > >
                >
                > > Well , in my case the SR6.3 produce the spike , even with no input (drive =0) or even without sound cables connected .
                >
                > > If I take the SR6.3 , connect only the 12V DC , and PTT using at battery , I can produce the spike .
                >
                > > However the funny stuff is that I get a spike on my first PTT keying , When I do #2 , 3 4... I have no spike . If I wait in rx for 2 minute , the spikes shows again! but only on the first PTT keying-
                >
                > >
                >
                > > --- In softrock40@yahoogroups.com, "alanzfq" <alan4alan@> wrote:
                >
                > > >
                >
                > > >
                >
                > > >
                >
                > > > --- In softrock40@yahoogroups.com, "chris" <oz1bxn@> wrote:
                >
                > > > >
                >
                > > > > I have a funny/serious problem ,
                >
                > > > > I switch on my SR6.3. then I start TX (either key down or MOX on PSDR IQ) . Herafter I get an RF spike of 10volts 1mS before normal output .
                >
                > > > >
                >
                > > > > Has someone else the same problem , and how did it solve?
                >
                > > > >
                >
                > > >
                >
                > > >
                >
                > > > Chris
                >
                > > >
                >
                > > > I have seen this, a long time ago.
                >
                > > > I do not remember how I reduced the effect but it was partly due to the way I had setup PSDR.
                >
                > > > I reduced the input gain of the Softrock so the soundcard would only just drive to maximum. (But a setting in PSDR compensates for this so this is probably not needed)
                >
                > > >
                >
                > > > But, I think, more important was that I read the manual and setup PSDR properly.
                >
                > > >
                >
                > > > 73 Alan G4ZFQ
                >
                > > >
                >
                > > >
                >
                > > > >
                >
                > > >
                >
                > >
                >
              • chris
                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 ...
                Message 7 of 19 , Mar 11, 2013
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                  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
                  And Yes no PC connections only PS and a load.

                  A Brazilian ZeroSDR writs in his project that the FTS3253 can spike if the output is not well balanced . This could indicate some problems with the PA unit , but again I have 4 of them , and I am not that bad with coils :)

                  You are right nobody has complained , but perhaps nobody realize the problem , Spikes are often overlooked . I have operated this unit without any problems or bad reports . But when I installed an "over hysterical" SCR SWR protection in my QRO PA and it began to show fault , I began to investigate.

                  73/chris


                  --- In softrock40@yahoogroups.com, "Alan" <alan4alan@...> wrote:
                  >
                  >
                  > ----- Original Message -----
                  > Subject: [softrock40] Re: spike on first TX after standby
                  >
                  >
                  > >but where to look ? I have the spike before the PA unit , so either switching , amp or mixer?
                  >
                  > Look at the schematic. What switches?
                  > Just like the Ensemble, the PA/driver supply with a few 0.1uFs which would discharge rapidly.
                  > And the RX mixer switches off.
                  >
                  > I cannot imagine what happens, as I say the 6.3 is almost identical to the Ensemble. Nobody has complained about that.
                  >
                  > I wonder if it is something like a ground loop, the switching surge inducing a pulse into the TX opamps?
                  > Does it do it with the audio input disconnected?
                  > Disable the opamps, ground the driver base, try to find a situation that it does not happen.
                  >
                  > 73 Alan G4ZFQ
                  >
                • warrenallgyer
                  Chris I have read all of these messages and it is not clear to ne what you are looking at when you see the spike. I assume you are using a scope if you could
                  Message 8 of 19 , Mar 11, 2013
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                    Chris

                    I have read all of these messages and it is not clear to ne what you are looking at when you see the spike. I assume you are using a scope if you could measure a 7 ms pulse. It would be interesting to know what frequency it is on.

                    Since you have a scope, if I were you I would work my way back. If you are seeing it on the output then do you see it on the collector of the driver. If so do you see it on the output of the mixer? If so to you see a spike on the audio input to the mixer?

                    At some point the spike will disappear and you will have isolated the stage that is causing it. Then the real fun begins.

                    The only two things I can see that could do this would be a momentary transient out of the transmit op amps that would unbalance the mixer. It should be easy to see and confirm on the hairpins of R3,6,9, and 12.

                    Warren Allgyer - W8TOD

                    --- In softrock40@yahoogroups.com, "chris" <oz1bxn@...> wrote:
                    >
                    > I have a funny/serious problem ,
                    > I switch on my SR6.3. then I start TX (either key down or MOX on PSDR IQ) . Herafter I get an RF spike of 10volts 1mS before normal output .
                    >
                    > Has someone else the same problem , and how did it solve?
                    >
                    > vy73 oz1bxn/chris
                    >
                  • Alan
                    ... Subject: [softrock40] Re: spike on first TX after standby ... Chris, I ve just tried with my 6.3 Monitoring with a receiver whose S meter shows over FSD on
                    Message 9 of 19 , Mar 12, 2013
                    ----- Original Message -----
                    Subject: [softrock40] Re: spike on first TX after standby


                    >
                    > You are right nobody has complained , but perhaps nobody realize the problem , Spikes are often overlooked . I have operated this
                    > unit without any problems or bad reports . But when I installed an "over hysterical" SCR SWR protection in my QRO PA and it began
                    > to show fault , I began to investigate.
                    >

                    Chris,

                    I've just tried with my 6.3
                    Monitoring with a receiver whose S meter shows over FSD on 2mW output from these rigs:_
                    I hear a click when PTT is set and a click when released. It is not a loud click. The click does not move the meter.
                    It does not move a 1 watt FSD power meter.

                    So, I thought "What is Chris talking about?"
                    BUT trying my USB scope showed it. TX WSPR Tune, 1 second.
                    Attached 1NoAF-COM is after standing, smaller one after several seconds.
                    So, this pulse is short enough not to be noticed normally?

                    I do not find this consistent, sometimes there is no pulse after waiting. Or not a second one after.

                    Now, I have a crude plug arrangement that gives me USB-AVR PTT. All it does is change PTT-I from COM port +ve to AVR pin 3. I think
                    this is all.

                    I started WSPR to give some audio (just enough to give a few mW) then used GFGSR to PTT, see 1USB-PTT
                    These seem to show that there is RF 1/2mS before the pulse.

                    Testing my 6.1 I do not see any pulse.

                    So, I see an intermittent PTT pulse.
                    Your comments indicate that this may be common to 6.3s. What causes it? I'm beginning to wonder if it is something in the plug-in
                    board layout, the schematic is almost identical to the Ensemble. Assuming the Ensemble is clean? There are likely far more of those
                    in use than 6.3s.
                    But strange it has not been reported before.

                    So wondering what next I thought grounding the hairpin of R26 might be worth a try.
                    This switches the TX mixer on (and disables the RX mixer).
                    So far I've seen no pulses.

                    IF this "cures" the problem I do not think that cutting a track and permanently grounding the TX mixer pins 1, 15 will have any
                    effect on operation. At least that will be my next test. When my "workshop" gets warmed up..
                    I am assuming that the actual RX mixer switching is not involved in producing the pulse.

                    73 Alan G4ZFQ
                  • 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 10 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 11 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 12 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 13 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 14 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 15 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 16 of 19 , Mar 14, 2013
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                                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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