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PowerSDR-IF question

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  • roger.shultz
    I don t know if this is the right forum to ask this or if it is more SoftRock40 related. I have a V9.0 softrock with Fred s upgraded ATTiny 85 processor
    Message 1 of 4 , May 6, 2009
      I don't know if this is the right forum to ask this or if it is more SoftRock40 related.

      I have a V9.0 softrock with Fred's upgraded ATTiny 85 processor running PowerSDR-IF v.92 from WU2X which is interfaced to my Kenwood TS-940SAT with Piexx board and Ham Radio Deluxe.

      Everything works pretty much as advertised though the bandwith of the Kenwood 8.83 KHz IF seems to be only about 16 KHz wide.

      I have two issues. The sensitivity of the PowerSDR-IF display does not seem to be all that sensitive. Yes, I can see signals similar to what I have seen using PowerSDR alone but they are lower. I set all parameters as shown in the WU2X web document.

      Second, I see the image on both sides of the received frequency with a dip in the middle, something I don't see when using just PowerSDR though I do see that condition when using Rocky.

      My soundcard is not impressive I know being a Creative Labs Soundblaster Live 24 bit.

      I'm puzzled though about why I see an image on some software and not PowerSDR. This makes the usefulness of the entire setup less than I had hoped for, so I am soliciting from those with far more experience what is the problem and what can I do to try and correct it?

      The Softrock40 V9.0 is a really impressive radio and I love it but the objective that took me down this path was to add a spectrum display to my Kenwood TS-940 to make spotting signals when using a transverter easy to find and go to.

      Thanks for any help!

      73, Roger, NJ2R
    • g8voip
      Hi Roger, You are probably more likely to get more answers on the Softrock40 group. I am not familiar with that version of PSDR you are using, but I believe
      Message 2 of 4 , May 7, 2009
        Hi Roger,

        You are probably more likely to get more answers on the 'Softrock40' group.

        I am not familiar with that version of PSDR you are using, but I believe the SoundBlaster Live 24 (PCI card)? requires a 1 bit delay inserting in the right channel in order to get proper image rejection.

        The Flexradio original versions of the software do not provide this support, only the modified ones like Christos PSDR-IQ or Guido PE1NNZ versions, again not sure about the one you are using.

        Apart from possibly needing the 1 bit delay with your soundcard, PSDR is the odd one out as far as I / Q signal polarity goes. If you have wired your hardware so that PSDR works ok for image rejection, in all other programs (Rocky, Winrad) you will need to swap the I/ Q signals in the software set-up (PSDR does not provide that facility). Perhaps that is why you have problems with Rocky, also you either need to either manually optimise the image rejection, or select the 'auto' mode.

        As far as 'smooth tuning' goes, if you are using a fixed centre frequency for an IF application, you are not actually using that function as you are not altering the Si570 LO frequency, just tuning within the sound card range in software.

        Hope that's of use,

        73, Bob G8VOI



        --- In powersdr-iq@yahoogroups.com, "roger.shultz" <nj2r@...> wrote:
        >
        > I don't know if this is the right forum to ask this or if it is more SoftRock40 related.
        >
        > I have a V9.0 softrock with Fred's upgraded ATTiny 85 processor running PowerSDR-IF v.92 from WU2X which is interfaced to my Kenwood TS-940SAT with Piexx board and Ham Radio Deluxe.
        >
        > Everything works pretty much as advertised though the bandwith of the Kenwood 8.83 KHz IF seems to be only about 16 KHz wide.
        >
        > I have two issues. The sensitivity of the PowerSDR-IF display does not seem to be all that sensitive. Yes, I can see signals similar to what I have seen using PowerSDR alone but they are lower. I set all parameters as shown in the WU2X web document.
        >
        > Second, I see the image on both sides of the received frequency with a dip in the middle, something I don't see when using just PowerSDR though I do see that condition when using Rocky.
        >
        > My soundcard is not impressive I know being a Creative Labs Soundblaster Live 24 bit.
        >
        > I'm puzzled though about why I see an image on some software and not PowerSDR. This makes the usefulness of the entire setup less than I had hoped for, so I am soliciting from those with far more experience what is the problem and what can I do to try and correct it?
        >
        > The Softrock40 V9.0 is a really impressive radio and I love it but the objective that took me down this path was to add a spectrum display to my Kenwood TS-940 to make spotting signals when using a transverter easy to find and go to.
        >
        > Thanks for any help!
        >
        > 73, Roger, NJ2R
        >
      • roger.shultz
        Thanks Bob. Your response gives me some direction. I think one thing to to is to add an I/Q reversing switch which may help with teh image problem. I think
        Message 3 of 4 , May 7, 2009
          Thanks Bob.

          Your response gives me some direction. I think one thing to to is to add an I/Q reversing switch which may help with teh image problem.

          I think PSDR-IF is based on an earlier version of PSDR v. 1.9.0 so many changes have occurred since then I realize.

          Yes, the center frequency doesn't really change since it is essentially "locked" at the Kenwood 8.8830 MHz IF frequency. I guess I ahve been spoiled by the performance I see using the newer versions of PSDR and I was hoping to see similar performance with the IF version.

          I guess that is what experimentation and trial and error is all about. Thanks for your help,

          73, Roger, NJ2R

          --- In powersdr-iq@yahoogroups.com, "g8voip" <g8voi.reeves59@...> wrote:
          >
          > Hi Roger,
          >
          > You are probably more likely to get more answers on the 'Softrock40' group.
          >
          > I am not familiar with that version of PSDR you are using, but I believe the SoundBlaster Live 24 (PCI card)? requires a 1 bit delay inserting in the right channel in order to get proper image rejection.
          >
          > The Flexradio original versions of the software do not provide this support, only the modified ones like Christos PSDR-IQ or Guido PE1NNZ versions, again not sure about the one you are using.
          >
          > Apart from possibly needing the 1 bit delay with your soundcard, PSDR is the odd one out as far as I / Q signal polarity goes. If you have wired your hardware so that PSDR works ok for image rejection, in all other programs (Rocky, Winrad) you will need to swap the I/ Q signals in the software set-up (PSDR does not provide that facility). Perhaps that is why you have problems with Rocky, also you either need to either manually optimise the image rejection, or select the 'auto' mode.
          >
          > As far as 'smooth tuning' goes, if you are using a fixed centre frequency for an IF application, you are not actually using that function as you are not altering the Si570 LO frequency, just tuning within the sound card range in software.
          >
          > Hope that's of use,
          >
          > 73, Bob G8VOI
          >
          >
          >
          > --- In powersdr-iq@yahoogroups.com, "roger.shultz" <nj2r@> wrote:
          > >
          > > I don't know if this is the right forum to ask this or if it is more SoftRock40 related.
          > >
          > > I have a V9.0 softrock with Fred's upgraded ATTiny 85 processor running PowerSDR-IF v.92 from WU2X which is interfaced to my Kenwood TS-940SAT with Piexx board and Ham Radio Deluxe.
          > >
          > > Everything works pretty much as advertised though the bandwith of the Kenwood 8.83 KHz IF seems to be only about 16 KHz wide.
          > >
          > > I have two issues. The sensitivity of the PowerSDR-IF display does not seem to be all that sensitive. Yes, I can see signals similar to what I have seen using PowerSDR alone but they are lower. I set all parameters as shown in the WU2X web document.
          > >
          > > Second, I see the image on both sides of the received frequency with a dip in the middle, something I don't see when using just PowerSDR though I do see that condition when using Rocky.
          > >
          > > My soundcard is not impressive I know being a Creative Labs Soundblaster Live 24 bit.
          > >
          > > I'm puzzled though about why I see an image on some software and not PowerSDR. This makes the usefulness of the entire setup less than I had hoped for, so I am soliciting from those with far more experience what is the problem and what can I do to try and correct it?
          > >
          > > The Softrock40 V9.0 is a really impressive radio and I love it but the objective that took me down this path was to add a spectrum display to my Kenwood TS-940 to make spotting signals when using a transverter easy to find and go to.
          > >
          > > Thanks for any help!
          > >
          > > 73, Roger, NJ2R
          > >
          >
        • g8voip
          Hi Roger, There s no need to wire up a switch to reverse the I / Q signals, just wire the receiver up correctly to work with PSDR. All of the other SDR
          Message 4 of 4 , May 7, 2009
            Hi Roger,

            There's no need to wire up a switch to reverse the I / Q signals, just wire the receiver up correctly to work with PSDR.

            All of the other SDR programs have a tick box option to reverse the I/Q in software. Makes life a lot easier that way, plus does not introduce any other possible reason to affect the I/Q phase or amplitude, which is critical for good image rejection.

            73, Bob G8VOI




            --- In powersdr-iq@yahoogroups.com, "roger.shultz" <nj2r@...> wrote:
            >
            > Thanks Bob.
            >
            > Your response gives me some direction. I think one thing to to is to add an I/Q reversing switch which may help with teh image problem.
            >
            > I think PSDR-IF is based on an earlier version of PSDR v. 1.9.0 so many changes have occurred since then I realize.
            >
            > Yes, the center frequency doesn't really change since it is essentially "locked" at the Kenwood 8.8830 MHz IF frequency. I guess I ahve been spoiled by the performance I see using the newer versions of PSDR and I was hoping to see similar performance with the IF version.
            >
            > I guess that is what experimentation and trial and error is all about. Thanks for your help,
            >
            > 73, Roger, NJ2R
            >
            > --- In powersdr-iq@yahoogroups.com, "g8voip" <g8voi.reeves59@> wrote:
            > >
            > > Hi Roger,
            > >
            > > You are probably more likely to get more answers on the 'Softrock40' group.
            > >
            > > I am not familiar with that version of PSDR you are using, but I believe the SoundBlaster Live 24 (PCI card)? requires a 1 bit delay inserting in the right channel in order to get proper image rejection.
            > >
            > > The Flexradio original versions of the software do not provide this support, only the modified ones like Christos PSDR-IQ or Guido PE1NNZ versions, again not sure about the one you are using.
            > >
            > > Apart from possibly needing the 1 bit delay with your soundcard, PSDR is the odd one out as far as I / Q signal polarity goes. If you have wired your hardware so that PSDR works ok for image rejection, in all other programs (Rocky, Winrad) you will need to swap the I/ Q signals in the software set-up (PSDR does not provide that facility). Perhaps that is why you have problems with Rocky, also you either need to either manually optimise the image rejection, or select the 'auto' mode.
            > >
            > > As far as 'smooth tuning' goes, if you are using a fixed centre frequency for an IF application, you are not actually using that function as you are not altering the Si570 LO frequency, just tuning within the sound card range in software.
            > >
            > > Hope that's of use,
            > >
            > > 73, Bob G8VOI
            > >
            > >
            > >
            > > --- In powersdr-iq@yahoogroups.com, "roger.shultz" <nj2r@> wrote:
            > > >
            > > > I don't know if this is the right forum to ask this or if it is more SoftRock40 related.
            > > >
            > > > I have a V9.0 softrock with Fred's upgraded ATTiny 85 processor running PowerSDR-IF v.92 from WU2X which is interfaced to my Kenwood TS-940SAT with Piexx board and Ham Radio Deluxe.
            > > >
            > > > Everything works pretty much as advertised though the bandwith of the Kenwood 8.83 KHz IF seems to be only about 16 KHz wide.
            > > >
            > > > I have two issues. The sensitivity of the PowerSDR-IF display does not seem to be all that sensitive. Yes, I can see signals similar to what I have seen using PowerSDR alone but they are lower. I set all parameters as shown in the WU2X web document.
            > > >
            > > > Second, I see the image on both sides of the received frequency with a dip in the middle, something I don't see when using just PowerSDR though I do see that condition when using Rocky.
            > > >
            > > > My soundcard is not impressive I know being a Creative Labs Soundblaster Live 24 bit.
            > > >
            > > > I'm puzzled though about why I see an image on some software and not PowerSDR. This makes the usefulness of the entire setup less than I had hoped for, so I am soliciting from those with far more experience what is the problem and what can I do to try and correct it?
            > > >
            > > > The Softrock40 V9.0 is a really impressive radio and I love it but the objective that took me down this path was to add a spectrum display to my Kenwood TS-940 to make spotting signals when using a transverter easy to find and go to.
            > > >
            > > > Thanks for any help!
            > > >
            > > > 73, Roger, NJ2R
            > > >
            > >
            >
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