Loading ...
Sorry, an error occurred while loading the content.

Removing mirror image signals

Expand Messages
  • bty230314
    Quite new to this, but already had a nice education and thrill through building RXTX6. Many thanks Tony et al. I have experimented with Rocky, SDR and M0KGK
    Message 1 of 27 , Apr 1, 2007
    • 0 Attachment
      Quite new to this, but already had a nice education and thrill
      through building RXTX6. Many thanks Tony et al.

      I have experimented with Rocky, SDR and M0KGK Software and all work
      sufficiently impressively for me to appreciate the potential. Its
      addictive to watch CW signals and use the bandwidth etc to resolve
      sigs that are very close together.

      However with my rx, I have not been able to reduce the mirror image
      sigs. I have read the many inputs and suggestions on this, but
      without success.

      Recent comments suggested that a cause of an image sig of approx the
      same strength may be caused by the absense of either the I or O
      sig. To see if this is my problem, I have looked at the Line-In Tip
      and Ring, but cannot see any sig with my 20mhertz scope. Should I
      see something ?? How would you determine if you are getting the
      appropriate sig at the Line-In Tip and Ring???

      I have also checked to see if the I and O are shorted--they are not.

      My sound cards are Creative Audigy ZS and Creative Audigy 24 Live
      (external- USB)

      I have not done much with the TX but have run the IQ GEN prog which
      produces a nice 20v pp sinewave with about 2.5 Vpp input. So that
      looks good. I have gone through the motions of keying but have only
      seen a very modest less than 1v pp output. Again checking Line-Out R
      and L , I cannot see any sig. What should I see??

      Any comments appreciated.

      Colin M3WCK
    • Tony Parks
      Hi Colin, Not sure, but I think your soundcard is one where a one sample-time offset compensation is needed. Several of the SDR programs provide for a +1 or
      Message 2 of 27 , Apr 1, 2007
      • 0 Attachment
        Hi Colin,
         
        Not sure, but I think your soundcard is one where a one sample-time offset compensation is needed.  Several of the SDR programs provide for a +1 or -1 sample-time offset selection and this and it should make all the difference in the RX image nulling.
         
        Your TX RF output sound right for the 2.5 v p-p quadrature audio input.  You should be able to use TX with your board without additional work.
         
        Good luck with your debug process.
         
        73,
        Tony KB9YIG
         
        ----- Original Message -----
        From: bty230314
        Sent: Sunday, April 01, 2007 1:02 PM
        Subject: [softrock40] Removing mirror image signals

        Quite new to this, but already had a nice education and thrill
        through building RXTX6. Many thanks Tony et al.

        I have experimented with Rocky, SDR and M0KGK Software and all work
        sufficiently impressively for me to appreciate the potential. Its
        addictive to watch CW signals and use the bandwidth etc to resolve
        sigs that are very close together.

        However with my rx, I have not been able to reduce the mirror image
        sigs. I have read the many inputs and suggestions on this, but
        without success.

        Recent comments suggested that a cause of an image sig of approx the
        same strength may be caused by the absense of either the I or O
        sig. To see if this is my problem, I have looked at the Line-In Tip
        and Ring, but cannot see any sig with my 20mhertz scope. Should I
        see something ?? How would you determine if you are getting the
        appropriate sig at the Line-In Tip and Ring???

        I have also checked to see if the I and O are shorted--they are not.

        My sound cards are Creative Audigy ZS and Creative Audigy 24 Live
        (external- USB)

        I have not done much with the TX but have run the IQ GEN prog which
        produces a nice 20v pp sinewave with about 2.5 Vpp input. So that
        looks good. I have gone through the motions of keying but have only
        seen a very modest less than 1v pp output. Again checking Line-Out R
        and L , I cannot see any sig. What should I see??

        Any comments appreciated.

        Colin M3WCK

      • k5nwa
        Depending on the input signal the output signal could be quite small, feed at least a 50 uV signal and your output will be in millivolts so unless you have a
        Message 3 of 27 , Apr 1, 2007
        • 0 Attachment
          Depending on the input signal the output signal could be quite small,
          feed at least a 50 uV signal and your output will be in millivolts so
          unless you have a really good oscilloscope feed it a large signal.

          If you don't have a signal generator, transmit into a dummy load and
          use a wire as an antenna, moving it closer to the dummy load to get a
          bigger signal. The output should be sine waves equal in amplitude and
          90 degrees apart.

          At 12:02 PM 4/1/2007, you wrote:

          >Quite new to this, but already had a nice education and thrill
          >through building RXTX6. Many thanks Tony et al.
          >
          >I have experimented with Rocky, SDR and M0KGK Software and all work
          >sufficiently impressively for me to appreciate the potential. Its
          >addictive to watch CW signals and use the bandwidth etc to resolve
          >sigs that are very close together.
          >
          >However with my rx, I have not been able to reduce the mirror image
          >sigs. I have read the many inputs and suggestions on this, but
          >without success.
          >
          >Recent comments suggested that a cause of an image sig of approx the
          >same strength may be caused by the absense of either the I or O
          >sig. To see if this is my problem, I have looked at the Line-In Tip
          >and Ring, but cannot see any sig with my 20mhertz scope. Should I
          >see something ?? How would you determine if you are getting the
          >appropriate sig at the Line-In Tip and Ring???
          >
          >I have also checked to see if the I and O are shorted--they are not.
          >
          >My sound cards are Creative Audigy ZS and Creative Audigy 24 Live
          >(external- USB)
          >
          >I have not done much with the TX but have run the IQ GEN prog which
          >produces a nice 20v pp sinewave with about 2.5 Vpp input. So that
          >looks good. I have gone through the motions of keying but have only
          >seen a very modest less than 1v pp output. Again checking Line-Out R
          >and L , I cannot see any sig. What should I see??
          >
          >Any comments appreciated.
          >
          >Colin M3WCK
          >
          >

          Cecil
          KD5NWA
          www.qrpradio.com www.hpsdr.com

          Cum catapultae proscriptae erunt tum soli proscripti catapultas habebunt.
          (When catapults are outlawed, only outlaws will have catapults!)
        • Terry
          From Terry, WB4JFI: If you feed a fairly strong rf signal into the Softrock receiver at near the LO frequency, you should see two sine waves on the audio
          Message 4 of 27 , Apr 1, 2007
          • 0 Attachment
            From Terry, WB4JFI:
            If you feed a fairly strong rf signal into the Softrock receiver at
            near the LO frequency, you should see two sine waves on the audio
            outputs (left & right) whose frequency should be the difference
            between the RF and LO signals. The two audio sine waves should be 90-
            degrees from each other.

            A short or missing I or Q signal on the SoftRock board are not the
            only potential culprits that cause image frequencies to show up.
            Others include:
            1. Mono input to sound card. Laptops are very bad for this. Most
            have mic-only inputs, which are not stereo.
            2. Samples from the sound card are one bit off in time. Most SDR
            software now allows you to adjust the I/Q bit timing.
            3. Stereo input, but mixer set for mono, or mixer input "balance
            control" not centered. Some Windows mixers do not come up in stereo,
            or they have been adjusted for all-left or all-right channel. Make
            sure the balance control is in the center. Remember, these mixer
            controls are the "record" controls, not the playback controls.

            You might check the computer input by making up a set of cables that
            goes from a stereo-mini plug to two RCA jacks, then two double-female
            RCA jacks, then another two-to stereo-mini. Also have a double-RCA
            (male or female) to RCA (female) Y-adaptor handy. Begin by taking an
            iPod or any other stereo audio source, and plug one end of a mini-
            stereo into it. Then, plug the other mini stereo into the PC line
            input. Now hook together the two sets of RCA ends with the barrels.

            Play the iPod, and listen to the stereo output of the PC. You should
            hear stereo audio once the mixer is setup properly (including setting
            the Window mixer temproarilty to enable line in on the line-output
            (called e-to-e). Now, disconnect only one RCA barrel, and one side
            of the stereo should disappear. Next, try the other RCA to make sure
            the other channel goes away. It is best to listen to the PC out with
            headsets or speakers where you can differentiate left and right.

            Now, using the Y adaptor (and possibly the RCA barrels), plug both
            ends of the cable leading into the PC line input to the Y adaptor.
            Then, plug the other end of the Y adaptor to one of the iPod
            outputs. This will create the same audio signal to both channels
            (mono). You can now verify proper balance of the PC line input
            because you will hear the same audio at the same level in each
            headset/speaker. You can verify channels by pulling one RCA from the
            cable leading to the PC line input. Only one channel should go away
            each time you do that. If you hear proper mono audio with both parts
            of the Y connected, and only one channel (cleanly) when you pull each
            of the line-input RCAs, then your PC sound system is working fine.

            If you hear wierd stuff, then eomething is wrong. Sometimes, inputs
            can be out-of-phase, causing a much lower and distorted signal when
            both channels are connected, but clean audio if only one is
            connected. Sometimes, the balance is off, or the input is set to
            mono, or many other things.

            I concentrated on checking the PC sound card input here. If you see
            a pair of good audio signals (sine waves) at the output of the
            SopftRock, and they are 90-degrees out of phase, then the SoftRock is
            probably working OK. If not, you need to look at the SoftRock some
            more. Common SoftRock issues are discussed in other emails, but we
            can help mre if you are concerned about the SoftRock itself.

            I have had badly made stereo mini-plug cables from Radio Shack. They
            were wired wrong, but that did not show up unit I checked them witht
            he above procedure. Then, ohming them out sometimes showed it and
            sometimes did not, depending on how the end connector was flexed. I
            ahve also seen mixer setting pinned to the left or right channel
            only, which will cause problems even though the hardware is fine.

            Let us know.
            Terry

            --- In softrock40@yahoogroups.com, "bty230314" <cweaving@...> wrote:
            >
            > Quite new to this, but already had a nice education and thrill
            > through building RXTX6. Many thanks Tony et al.
            >
            > I have experimented with Rocky, SDR and M0KGK Software and all work
            > sufficiently impressively for me to appreciate the potential. Its
            > addictive to watch CW signals and use the bandwidth etc to resolve
            > sigs that are very close together.
            >
            > However with my rx, I have not been able to reduce the mirror image
            > sigs. I have read the many inputs and suggestions on this, but
            > without success.
            >
            > Recent comments suggested that a cause of an image sig of approx
            the
            > same strength may be caused by the absense of either the I or O
            > sig. To see if this is my problem, I have looked at the Line-In
            Tip
            > and Ring, but cannot see any sig with my 20mhertz scope. Should I
            > see something ?? How would you determine if you are getting the
            > appropriate sig at the Line-In Tip and Ring???
            >
            > I have also checked to see if the I and O are shorted--they are not.
            >
            > My sound cards are Creative Audigy ZS and Creative Audigy 24 Live
            > (external- USB)
            >
            > I have not done much with the TX but have run the IQ GEN prog
            which
            > produces a nice 20v pp sinewave with about 2.5 Vpp input. So that
            > looks good. I have gone through the motions of keying but have only
            > seen a very modest less than 1v pp output. Again checking Line-Out
            R
            > and L , I cannot see any sig. What should I see??
            >
            > Any comments appreciated.
            >
            > Colin M3WCK
            >
          • C WEAVING
            Hi Terry and others, Great response--thank you. I think Terry s reply would have great merit as a File for referance for new builders. I am clearly not alone
            Message 5 of 27 , Apr 2, 2007
            • 0 Attachment
              Hi Terry and others,
               
              Great response--thank you.
               
              I think Terry's reply would have great merit as a File for referance for new  builders. I am clearly not alone with the image problem, and for some of us, the SoftRock/ Radio/Computer  combo, is a lot to get our heads around.
               
              Terry covered several of the points that I had dug out from previous postings, and others which I was unaware of. Maybe of more importance, i also have a better understandinf of how this wonderful toy works.
               
              I have some work to do following the suggestions made. Unfortunately I will be away for two weeks, but shortly after that hope to report a successful trouble-shoot.
               
              Thank you Colin 
               
            • geoffrey_cottrell
              Hello Group ... I have just done Terry s simple first test on the audio signal outputs - the ring o/p is fine - obeys the rule (i.e. freq varies with
              Message 6 of 27 , Apr 17, 2007
              • 0 Attachment
                Hello Group

                --- In softrock40@yahoogroups.com, "Terry" <wb4jfi@...> wrote:
                >
                > From Terry, WB4JFI:
                > If you feed a fairly strong rf signal into the Softrock receiver at
                > near the LO frequency, you should see two sine waves on the audio
                > outputs (left & right) whose frequency should be the difference
                > between the RF and LO signals. The two audio sine waves should be 90-
                > degrees from each other.
                >
                > I concentrated on checking the PC sound card input here. If you see
                > a pair of good audio signals (sine waves) at the output of the
                > SopftRock, and they are 90-degrees out of phase, then the SoftRock is
                > probably working OK. If not, you need to look at the SoftRock some
                > more. Common SoftRock issues are discussed in other emails, but we
                > can help mre if you are concerned about the SoftRock itself.
                >
                I have just done Terry's simple first test on the audio signal outputs - the "ring" o/p is fine
                - obeys the rule (i.e. freq varies with difference between SR xtal and sig gen freq), but
                there is no signal on the "tip" o/p at all.

                As a beginner - what should I do next?

                Thanks in advance for any help
                Geoff
                G3XGC
              • Terry
                ... at ... be 90- ... see ... SoftRock is ... some ... we ... outputs - the ring o/p is fine ... and sig gen freq), but ... Hello Geoff: Make sure your cable
                Message 7 of 27 , Apr 17, 2007
                • 0 Attachment
                  --- In softrock40@yahoogroups.com, "geoffrey_cottrell" <g3.xgc@...>
                  wrote:
                  >
                  > Hello Group
                  >
                  > --- In softrock40@yahoogroups.com, "Terry" <wb4jfi@> wrote:
                  > >
                  > > From Terry, WB4JFI:
                  > > If you feed a fairly strong rf signal into the Softrock receiver
                  at
                  > > near the LO frequency, you should see two sine waves on the audio
                  > > outputs (left & right) whose frequency should be the difference
                  > > between the RF and LO signals. The two audio sine waves should
                  be 90-
                  > > degrees from each other.
                  > >
                  > > I concentrated on checking the PC sound card input here. If you
                  see
                  > > a pair of good audio signals (sine waves) at the output of the
                  > > SopftRock, and they are 90-degrees out of phase, then the
                  SoftRock is
                  > > probably working OK. If not, you need to look at the SoftRock
                  some
                  > > more. Common SoftRock issues are discussed in other emails, but
                  we
                  > > can help mre if you are concerned about the SoftRock itself.
                  > >
                  > I have just done Terry's simple first test on the audio signal
                  outputs - the "ring" o/p is fine
                  > - obeys the rule (i.e. freq varies with difference between SR xtal
                  and sig gen freq), but
                  > there is no signal on the "tip" o/p at all.
                  >
                  > As a beginner - what should I do next?
                  >
                  > Thanks in advance for any help
                  > Geoff
                  > G3XGC
                  >
                  Hello Geoff:
                  Make sure your cable is not shorting out the audio for the tip side.
                  Disconnect the wire (if you have a connector of the board) and check
                  both the tip and ring for similar signals. I use single inline
                  connectors between the board and power, antenna, and audio output
                  cables. That makes it easy to quickly change boards.

                  Do you have a scope and/or DMM? If so, you should be able to
                  troubleshoot fairly easily.

                  Since one channel is working right, I think we can assume the
                  oscillator, divider chain, and QSD are all probably working OK.
                  There is a slight possibility that a only portion of the QSD chip
                  itself is bad, but that's not likely.

                  Verify the resistor values are correct (especially R10=10ohm &
                  R11=1.0k). Since the two halves of U5 are the same circuit, you
                  should be able to compare between them. The ring (good) signal comes
                  from U5B, pins 5, 6, and 7. Your problem is in U5A, pins 2, 3, and
                  1. Check the soldering around the capacitor just above U5, close to
                  the board edge, to make sure there are no solder shorts there. Also
                  check U5 pins 1, 2, 3 for shorts.

                  U5 pins 1, 2, 3, 5, 6, 7, should all read about one-half the voltage
                  regulator out. Mine is a little low at 4.9V from the regulator, so I
                  read 2.44V on all those pins. If they are right, it must be an AC
                  problem, not bias or voltage divider issue.

                  I fed a -20dbm signal into the antenna input of my SoftRock lite,
                  designed for 10.7MHz IF operation. Audio IF signal at SR Lite output
                  was at 34.7kHz in my case. At that level, I saw approx. 220mV p-p
                  (scope) on the RING out (52mV on AC scale of decent DMM), and at the
                  TIP output approx 210mV p-p (scope), 48mV on DMM. I could not see
                  anything on the opamp input pins.

                  I then fed 0dbm signal into antenna, and read:
                  Ring out & U5 pin 7 2.4V p-p (scope), 0.398V on DMM AC scale
                  U5 pin 6 approx 30mV p-p (scope) - nothing on DMM
                  U5 pin 5 approx 20mV p-p (scope) - nothing on DMM
                  (note that this should be 0 signal, bypass caps)
                  Tip out & U5 pin 1 2.1V p-p (scope) and 0.368V on DMM AC scale
                  U5 pin 2 approx 20mv p-p (scope) - nothing on DMM
                  U5 pin 3 approx 20mv p-p (scope) - nothing on DMM
                  (note pin 3 should be 0, like pin 5)

                  If you use a DMM on AC scale, make sure it is a decent DMM. The ten
                  dollar Radio Shack wonders do NOT work well. I tested two, and had
                  no reading at all on either one.

                  Rocky was showing a very strong signal, with a strong image at these
                  rf input levels.

                  Let me know if that helps.
                  Terry
                • Terry
                  Sorry, to clarify the comment about U5 pins 1, 2, 3, 5, 6, 7 all reading 1/2 the regulator out: Those should ALL be DC voltage readings. Terry ... receiver
                  Message 8 of 27 , Apr 17, 2007
                  • 0 Attachment
                    Sorry, to clarify the comment about U5 pins 1, 2, 3, 5, 6, 7 all
                    reading 1/2 the regulator out: Those should ALL be DC voltage
                    readings.
                    Terry


                    --- In softrock40@yahoogroups.com, "Terry" <wb4jfi@...> wrote:
                    >
                    > --- In softrock40@yahoogroups.com, "geoffrey_cottrell" <g3.xgc@>
                    > wrote:
                    > >
                    > > Hello Group
                    > >
                    > > --- In softrock40@yahoogroups.com, "Terry" <wb4jfi@> wrote:
                    > > >
                    > > > From Terry, WB4JFI:
                    > > > If you feed a fairly strong rf signal into the Softrock
                    receiver
                    > at
                    > > > near the LO frequency, you should see two sine waves on the
                    audio
                    > > > outputs (left & right) whose frequency should be the difference
                    > > > between the RF and LO signals. The two audio sine waves should
                    > be 90-
                    > > > degrees from each other.
                    > > >
                    > > > I concentrated on checking the PC sound card input here. If
                    you
                    > see
                    > > > a pair of good audio signals (sine waves) at the output of the
                    > > > SopftRock, and they are 90-degrees out of phase, then the
                    > SoftRock is
                    > > > probably working OK. If not, you need to look at the SoftRock
                    > some
                    > > > more. Common SoftRock issues are discussed in other emails,
                    but
                    > we
                    > > > can help mre if you are concerned about the SoftRock itself.
                    > > >
                    > > I have just done Terry's simple first test on the audio signal
                    > outputs - the "ring" o/p is fine
                    > > - obeys the rule (i.e. freq varies with difference between SR
                    xtal
                    > and sig gen freq), but
                    > > there is no signal on the "tip" o/p at all.
                    > >
                    > > As a beginner - what should I do next?
                    > >
                    > > Thanks in advance for any help
                    > > Geoff
                    > > G3XGC
                    > >
                    > Hello Geoff:
                    > Make sure your cable is not shorting out the audio for the tip
                    side.
                    > Disconnect the wire (if you have a connector of the board) and
                    check
                    > both the tip and ring for similar signals. I use single inline
                    > connectors between the board and power, antenna, and audio output
                    > cables. That makes it easy to quickly change boards.
                    >
                    > Do you have a scope and/or DMM? If so, you should be able to
                    > troubleshoot fairly easily.
                    >
                    > Since one channel is working right, I think we can assume the
                    > oscillator, divider chain, and QSD are all probably working OK.
                    > There is a slight possibility that a only portion of the QSD chip
                    > itself is bad, but that's not likely.
                    >
                    > Verify the resistor values are correct (especially R10=10ohm &
                    > R11=1.0k). Since the two halves of U5 are the same circuit, you
                    > should be able to compare between them. The ring (good) signal
                    comes
                    > from U5B, pins 5, 6, and 7. Your problem is in U5A, pins 2, 3, and
                    > 1. Check the soldering around the capacitor just above U5, close
                    to
                    > the board edge, to make sure there are no solder shorts there.
                    Also
                    > check U5 pins 1, 2, 3 for shorts.
                    >
                    > U5 pins 1, 2, 3, 5, 6, 7, should all read about one-half the
                    voltage
                    > regulator out. Mine is a little low at 4.9V from the regulator, so
                    I
                    > read 2.44V on all those pins. If they are right, it must be an AC
                    > problem, not bias or voltage divider issue.
                    >
                    > I fed a -20dbm signal into the antenna input of my SoftRock lite,
                    > designed for 10.7MHz IF operation. Audio IF signal at SR Lite
                    output
                    > was at 34.7kHz in my case. At that level, I saw approx. 220mV p-p
                    > (scope) on the RING out (52mV on AC scale of decent DMM), and at
                    the
                    > TIP output approx 210mV p-p (scope), 48mV on DMM. I could not see
                    > anything on the opamp input pins.
                    >
                    > I then fed 0dbm signal into antenna, and read:
                    > Ring out & U5 pin 7 2.4V p-p (scope), 0.398V on DMM AC scale
                    > U5 pin 6 approx 30mV p-p (scope) - nothing on DMM
                    > U5 pin 5 approx 20mV p-p (scope) - nothing on DMM
                    > (note that this should be 0 signal, bypass caps)
                    > Tip out & U5 pin 1 2.1V p-p (scope) and 0.368V on DMM AC scale
                    > U5 pin 2 approx 20mv p-p (scope) - nothing on DMM
                    > U5 pin 3 approx 20mv p-p (scope) - nothing on DMM
                    > (note pin 3 should be 0, like pin 5)
                    >
                    > If you use a DMM on AC scale, make sure it is a decent DMM. The
                    ten
                    > dollar Radio Shack wonders do NOT work well. I tested two, and had
                    > no reading at all on either one.
                    >
                    > Rocky was showing a very strong signal, with a strong image at
                    these
                    > rf input levels.
                    >
                    > Let me know if that helps.
                    > Terry
                    >
                  • geoffrey_cottrell
                    Hi Terry and the group I should have mentioned that I have the RXTX 6.1 here. ... Measurements were made on the board, with no cables connected. ... Ring was
                    Message 9 of 27 , Apr 18, 2007
                    • 0 Attachment
                      Hi Terry and the group

                      I should have mentioned that I have the RXTX 6.1 here.

                      > > --- In softrock40@yahoogroups.com, "Terry" <wb4jfi@> wrote:

                      > Hello Geoff:
                      > Make sure your cable is not shorting out the audio for the tip side.

                      Measurements were made on the board, with no cables connected.
                      > Disconnect the wire (if you have a connector of the board) and check
                      > both the tip and ring for similar signals.

                      Ring was OK - nil signal on tip.
                      >
                      > Do you have a scope and/or DMM? If so, you should be able to
                      > troubleshoot fairly easily.
                      Yes I do

                      > Since one channel is working right, I think we can assume the
                      > oscillator, divider chain, and QSD are all probably working OK.
                      > There is a slight possibility that a only portion of the QSD chip
                      > itself is bad, but that's not likely.
                      >
                      > Verify the resistor values are correct (especially R10=10ohm &
                      > R11=1.0k). Since the two halves of U5 are the same circuit, you
                      > should be able to compare between them. The ring (good) signal comes
                      > from U5B, pins 5, 6, and 7. Your problem is in U5A, pins 2, 3, and
                      > 1. Check the soldering around the capacitor just above U5, close to
                      > the board edge, to make sure there are no solder shorts there. Also
                      > check U5 pins 1, 2, 3 for shorts.
                      >
                      > U5 pins 1, 2, 3, 5, 6, 7, should all read about one-half the voltage
                      > regulator out. Mine is a little low at 4.9V from the regulator, so I
                      > read 2.44V on all those pins. If they are right, it must be an AC
                      > problem, not bias or voltage divider issue.

                      Do you know equivalent pin numbers for the RXTX?

                      Thanks

                      Geoff
                      G3XGC
                    • Len Warner
                      ... Terry, I m mostly very impressed by your testing technique ... How do you know this? We have no idea of Geoff s signal levels, only that he sees a
                      Message 10 of 27 , Apr 18, 2007
                      • 0 Attachment
                        At 08:41 07/04/18, Digest Number 1498 4b. wrote:
                        > Posted by: "Terry" wb4jfi@... wb4jfi
                        > Date: Tue Apr 17, 2007 1:22 pm ((PDT))
                        >[snip]

                        Terry, I'm mostly very impressed by your testing technique
                        except for this first point:

                        >Since one channel is working right,

                        How do you know this? We have no idea of Geoff's signal levels,
                        only that he sees a difference frequency of the right value.
                        It only takes one semiconductor junction to do that.

                        > I think we can assume the
                        >oscillator, divider chain, and QSD are all probably working OK.

                        Only if you can be reasonably confident that the divider chain _is_
                        working can you deduce that one baseband channel might be
                        being demodulated correctly - otherwise your reasoning is circular.

                        You can be fairly confident of the divider chain if the flip-flop
                        outputs measure mid-rail on a DC meter. If an output is
                        at Vcc or ground then that stage isn't clocking properly.

                        [Ok, quibble over ;-) ]

                        Similarly, the opamp inputs and outputs should be near
                        mid-rail: the inputs because they are biassed that way
                        and the outputs because of negative feedback.

                        If the outputs of a Softrock opamp are around mid-rail
                        then most of the circuit around it is likely ok.

                        A tiny difference in input voltages (that you probably wouldn't
                        be able to measure) will tip the output to one extreme or the
                        other. If the feedback connection is open circuit this could
                        happen easily, if the feedback connection is intact it will take
                        a stronger imbalance in the input to force the amp off-centre
                        and you have a greater chance of being able to spot it by DMM..

                        >[snip]
                        >I fed a -20dbm signal into the antenna input of my SoftRock lite,
                        >[snip] I could not see anything on the opamp input pins.
                        >
                        >I then fed 0dbm signal into antenna, and read:
                        >[snip]
                        > U5 pin 5 approx 20mV p-p (scope) - nothing on DMM
                        > (note that this should be 0 signal, bypass caps)

                        Yeah, right, probably - in theory ;-)

                        But we don't know how good that 10uF is at 10.7MHz and we
                        ought to expect some effect from the charge/discharge currents
                        to C11 & C13, which are not that much smaller than C20+C18;
                        nor do we have a spec for commutation drive crosstalk in the
                        switch, which may well be signal level dependant; and
                        the input signal is 100x so the stray pickup will 100x too
                        (20mVpp from 0dBm would only be 2mVpp at -20dBm)

                        So it's not a surprise to see _something_ there: explaining what
                        causes it is more difficult ;-)

                        Terry, is seems to me that some people are taking an unconscionably
                        long time to get their Softrock working and some of them should be
                        commended for their fortitude in "hangin' on in there".

                        What should have been (and is) a simple hardware project drags on
                        and on and they can't be blamed if they can't read circuit diagrams,
                        don't have much test equipment or any RF testing skills.

                        We really need to find a simple way to debug these projects that
                        needs minimal testgear and knowhow and I think your detailed
                        measurements are laying the ground for this.


                        Regards, LenW
                        --
                        From Yahoo! Groups help: ... trim all the irrelevant quoted text out of
                        your message
                        (as a courtesy to the other members of the group to make the digest
                        easier to read).
                      • geoffrey_cottrell
                        Hi Terry ... Following your logic, I have just checked the pins DC voltages of U8 on the RXTX board. I guess analagous to U5 on SR40 RX. They are: pin 1 2.76V
                        Message 11 of 27 , Apr 18, 2007
                        • 0 Attachment
                          Hi Terry

                          --- In softrock40@yahoogroups.com, "Terry" <wb4jfi@...> wrote:
                          >
                          > Sorry, to clarify the comment about U5 pins 1, 2, 3, 5, 6, 7 all
                          > reading 1/2 the regulator out: Those should ALL be DC voltage
                          > readings.
                          > Terry
                          >
                          >

                          Following your logic, I have just checked the pins DC voltages of U8
                          on the RXTX board. I guess analagous to U5 on SR40 RX. They are:
                          pin 1 2.76V
                          pin 2 3.14V
                          pin 3 3.14V
                          pin 4 0V
                          pin 5 3.14V
                          pin 6 3.1V
                          pin 7 4.95V
                          pin 8 4.95V

                          The regulator volts is 4.98V.

                          Seems that pin 7 is too high. No shorts between U8 pins.

                          Any thoughts?

                          73
                          Geoff
                          G3XGC
                        • Terry
                          Thanks for the comments Len. My comments embedded. ... You are correct that we don t know how sensitive the receiver is. I am assuming that since a signal
                          Message 12 of 27 , Apr 18, 2007
                          • 0 Attachment
                            Thanks for the comments Len. My comments embedded.
                            --- In softrock40@yahoogroups.com, Len Warner <novost@...> wrote:
                            >
                            > At 08:41 07/04/18, Digest Number 1498 4b. wrote:
                            > > Posted by: "Terry" wb4jfi@... wb4jfi
                            > > Date: Tue Apr 17, 2007 1:22 pm ((PDT))
                            > >[snip]
                            >
                            > Terry, I'm mostly very impressed by your testing technique
                            > except for this first point:
                            >
                            > >Since one channel is working right,
                            >
                            > How do you know this? We have no idea of Geoff's signal levels,
                            > only that he sees a difference frequency of the right value.
                            > It only takes one semiconductor junction to do that.
                            >

                            You are correct that we don't know how sensitive the receiver is. I
                            am assuming that since a signal shows up on one output that mimics
                            somewhat what I expect (output changes with input frequency change),
                            and NO SIGNAL AT ALL on the other output, that the output with no
                            signal is the problem. But, I am making MANY assumptions here. For
                            exmaple, can he drive the signal source properly, and should there
                            even be a signal present at all? It could be that he is driving the
                            antenna input with a totally wrong signal and there should be no
                            output. Then, the assumed good but defective channel is creating a
                            false signal due to bad mixing, a bad capacitor, or the phase of the
                            moon is wrong.

                            Bench troubleshooting requires some assumptions, especially when
                            trying to do it remotely.

                            How likely is it that some simple but defective receiver is magically
                            transforming the wanted signal to another wanted signal at close to
                            the right frequency in a way that mimics a functioning receiver? It
                            is more likely that if he is seeing a frequency conversion close to
                            what is expected (another assumption I know), that the receiver is in
                            fact working to some degree.

                            It typically takes more than a diode to cause a frequency conversion
                            that matches what one expects to see. Is it theoretically possible
                            for the diode to mix another signal and cause the desired result, but
                            isn't it more likely that most of the receiver is in fact working as
                            designed, than think some unknown signal is mixing?

                            > > I think we can assume the
                            > >oscillator, divider chain, and QSD are all probably working OK.
                            >
                            > Only if you can be reasonably confident that the divider chain _is_
                            > working can you deduce that one baseband channel might be
                            > being demodulated correctly - otherwise your reasoning is circular.
                            >
                            > You can be fairly confident of the divider chain if the flip-flop
                            > outputs measure mid-rail on a DC meter. If an output is
                            > at Vcc or ground then that stage isn't clocking properly.
                            >
                            Again, if the receiver is converting a known good signal into another
                            expected signal, the frequency conversion ciruitry is probably
                            working. The simpler answer is most likely correct. For the
                            frequency conversion to be working, either the divider chain is
                            working, or somewhere else there is something generating the right
                            conversion as if by magic. I'll go with the oscillator and divider
                            working.

                            I took him at his word (assumption) that he is seeing - probably via
                            software such as Rocky - that is he feeds a signal into the Lite at
                            the right frequency, he is in fact seeing a result that is consistent
                            with correct frequency conversion. I guess he could be feeding in an
                            AM boradcast signal, and the conversion circuit is not right, but the
                            QSD capacitors and opamps are miswired to the point that they react
                            to the AM signal. There are lots of potentials, but the assumtions
                            that he is not trying to mess with us and he is asking for real help,
                            and that the receiver is actually close to really working, but has
                            one small problem in one output circuit is much higher in my book.

                            I am just trying to help. I did not see a lot of other responses
                            here. Some builders need real, practical help. My response would be
                            a LOT longer if I took into account even most of the possible issues,
                            and not just the likely ones.

                            Yes, he could check the oscillator and divider chain with a scope, or
                            the dividers with a DMM. That testing was covered a whle back in
                            another email. Maybe we need to make a troubleshooting document that
                            combines various comments and suggestions, and is proerly vetted.

                            > [Ok, quibble over ;-) ]
                            Quibble response over.

                            >
                            > Similarly, the opamp inputs and outputs should be near
                            > mid-rail: the inputs because they are biassed that way
                            > and the outputs because of negative feedback.
                            >
                            > If the outputs of a Softrock opamp are around mid-rail
                            > then most of the circuit around it is likely ok.
                            >
                            > A tiny difference in input voltages (that you probably wouldn't
                            > be able to measure) will tip the output to one extreme or the
                            > other. If the feedback connection is open circuit this could
                            > happen easily, if the feedback connection is intact it will take
                            > a stronger imbalance in the input to force the amp off-centre
                            > and you have a greater chance of being able to spot it by DMM..
                            >
                            > >[snip]
                            > >I fed a -20dbm signal into the antenna input of my SoftRock lite,
                            > >[snip] I could not see anything on the opamp input pins.
                            > >
                            > >I then fed 0dbm signal into antenna, and read:
                            > >[snip]
                            > > U5 pin 5 approx 20mV p-p (scope) - nothing on DMM
                            > > (note that this should be 0 signal, bypass caps)
                            >
                            > Yeah, right, probably - in theory ;-)
                            >
                            > But we don't know how good that 10uF is at 10.7MHz and we
                            > ought to expect some effect from the charge/discharge currents
                            > to C11 & C13, which are not that much smaller than C20+C18;
                            > nor do we have a spec for commutation drive crosstalk in the
                            > switch, which may well be signal level dependant; and
                            > the input signal is 100x so the stray pickup will 100x too
                            > (20mVpp from 0dBm would only be 2mVpp at -20dBm)
                            >
                            > So it's not a surprise to see _something_ there: explaining what
                            > causes it is more difficult ;-)
                            >
                            Plus, it is likely that my scope probes have some stray pickup of RF
                            at 50mV per division.

                            > Terry, is seems to me that some people are taking an unconscionably
                            > long time to get their Softrock working and some of them should be
                            > commended for their fortitude in "hangin' on in there".
                            >
                            > What should have been (and is) a simple hardware project drags on
                            > and on and they can't be blamed if they can't read circuit diagrams,
                            > don't have much test equipment or any RF testing skills.
                            >
                            > We really need to find a simple way to debug these projects that
                            > needs minimal testgear and knowhow and I think your detailed
                            > measurements are laying the ground for this.
                            >
                            I agree totally. I think someone should create a set of documents to
                            assist in troubleshooting. I would be glad to provide some input,
                            but I'm not capable of generating the final version (obviously).

                            I have tried to help as I can, using my 40+ years bench experience.
                            But, I only have practical, real-world experience (:<). That would
                            probably get in the way of the theory behind how this stuff works.

                            Thanks again for providing a way to clarify the above for others here
                            on the group.
                            Terry

                            >
                            > Regards, LenW
                            > --
                            > From Yahoo! Groups help: ... trim all the irrelevant quoted text
                            out of
                            > your message
                            > (as a courtesy to the other members of the group to make the
                            digest
                            > easier to read).
                            >
                          • Terry
                            I will compare the schematics and get back to you shortly. Terry ... side. ... check ... comes ... and ... to ... Also ... voltage ... so I ... AC
                            Message 13 of 27 , Apr 18, 2007
                            • 0 Attachment
                              I will compare the schematics and get back to you shortly.
                              Terry

                              --- In softrock40@yahoogroups.com, "geoffrey_cottrell" <g3.xgc@...>
                              wrote:
                              >
                              > Hi Terry and the group
                              >
                              > I should have mentioned that I have the RXTX 6.1 here.
                              >
                              > > > --- In softrock40@yahoogroups.com, "Terry" <wb4jfi@> wrote:
                              >
                              > > Hello Geoff:
                              > > Make sure your cable is not shorting out the audio for the tip
                              side.
                              >
                              > Measurements were made on the board, with no cables connected.
                              > > Disconnect the wire (if you have a connector of the board) and
                              check
                              > > both the tip and ring for similar signals.
                              >
                              > Ring was OK - nil signal on tip.
                              > >
                              > > Do you have a scope and/or DMM? If so, you should be able to
                              > > troubleshoot fairly easily.
                              > Yes I do
                              >
                              > > Since one channel is working right, I think we can assume the
                              > > oscillator, divider chain, and QSD are all probably working OK.
                              > > There is a slight possibility that a only portion of the QSD chip
                              > > itself is bad, but that's not likely.
                              > >
                              > > Verify the resistor values are correct (especially R10=10ohm &
                              > > R11=1.0k). Since the two halves of U5 are the same circuit, you
                              > > should be able to compare between them. The ring (good) signal
                              comes
                              > > from U5B, pins 5, 6, and 7. Your problem is in U5A, pins 2, 3,
                              and
                              > > 1. Check the soldering around the capacitor just above U5, close
                              to
                              > > the board edge, to make sure there are no solder shorts there.
                              Also
                              > > check U5 pins 1, 2, 3 for shorts.
                              > >
                              > > U5 pins 1, 2, 3, 5, 6, 7, should all read about one-half the
                              voltage
                              > > regulator out. Mine is a little low at 4.9V from the regulator,
                              so I
                              > > read 2.44V on all those pins. If they are right, it must be an
                              AC
                              > > problem, not bias or voltage divider issue.
                              >
                              > Do you know equivalent pin numbers for the RXTX?
                              >
                              > Thanks
                              >
                              > Geoff
                              > G3XGC
                              >
                            • Terry
                              It took me a while to find my RxTX schematics. I have a prototype RxTx built, but my production RxTx is still in kit form. You are correct, U8 on the RxTx
                              Message 14 of 27 , Apr 18, 2007
                              • 0 Attachment
                                It took me a while to find my RxTX schematics. I have a prototype
                                RxTx built, but my production RxTx is still in kit form.

                                You are correct, U8 on the RxTx would be similar to U5 on the SR Lite.

                                I would agree that U8, pin 7 seems high. Is it coincidental that pin
                                7 is right next to supply voltage to U8 on pin 8? Can you double
                                check with an ohm meter that pins 7 & 8 are not shorted? It could
                                also be that U8 is defective, or many other possibilities around
                                that. My guess is that your problem is right there in U8B (pins 5-7).

                                In looking at my unbuild board, there does appear to be adequate
                                separation of traces. I remember Tony mentioning that there was a
                                problem on a limited number of PC boards for the RxTx, but I can't
                                find the email about that right now. I don't think it was around U8,
                                however.

                                Your center voltage at 3.14V seems a little high as well, but I doubt
                                that is the main problem.

                                Please let us know what you find.
                                Terry


                                --- In softrock40@yahoogroups.com, "geoffrey_cottrell" <g3.xgc@...>
                                wrote:
                                >
                                > Hi Terry
                                >
                                > --- In softrock40@yahoogroups.com, "Terry" <wb4jfi@> wrote:
                                > >
                                > > Sorry, to clarify the comment about U5 pins 1, 2, 3, 5, 6, 7 all
                                > > reading 1/2 the regulator out: Those should ALL be DC voltage
                                > > readings.
                                > > Terry
                                > >
                                > >
                                >
                                > Following your logic, I have just checked the pins DC voltages of U8
                                > on the RXTX board. I guess analagous to U5 on SR40 RX. They are:
                                > pin 1 2.76V
                                > pin 2 3.14V
                                > pin 3 3.14V
                                > pin 4 0V
                                > pin 5 3.14V
                                > pin 6 3.1V
                                > pin 7 4.95V
                                > pin 8 4.95V
                                >
                                > The regulator volts is 4.98V.
                                >
                                > Seems that pin 7 is too high. No shorts between U8 pins.
                                >
                                > Any thoughts?
                                >
                                > 73
                                > Geoff
                                > G3XGC
                                >
                              • Terry
                                I found the email about shorrts on the RxTx boards. They were shorts to ground, so that s probably not your problem. But, I would check around pin 7 to make
                                Message 15 of 27 , Apr 18, 2007
                                • 0 Attachment
                                  I found the email about shorrts on the RxTx boards. They were shorts
                                  to ground, so that's probably not your problem. But, I would check
                                  around pin 7 to make sure it is not shorted to VCC anyway. Double-
                                  check with a meter, as a very thin short could occur, even under the
                                  IC.
                                  Terry


                                  --- In softrock40@yahoogroups.com, "Terry" <wb4jfi@...> wrote:
                                  >
                                  > It took me a while to find my RxTX schematics. I have a prototype
                                  > RxTx built, but my production RxTx is still in kit form.
                                  >
                                  > You are correct, U8 on the RxTx would be similar to U5 on the SR
                                  Lite.
                                  >
                                  > I would agree that U8, pin 7 seems high. Is it coincidental that
                                  pin
                                  > 7 is right next to supply voltage to U8 on pin 8? Can you double
                                  > check with an ohm meter that pins 7 & 8 are not shorted? It could
                                  > also be that U8 is defective, or many other possibilities around
                                  > that. My guess is that your problem is right there in U8B (pins 5-
                                  7).
                                  >
                                  > In looking at my unbuild board, there does appear to be adequate
                                  > separation of traces. I remember Tony mentioning that there was a
                                  > problem on a limited number of PC boards for the RxTx, but I can't
                                  > find the email about that right now. I don't think it was around
                                  U8,
                                  > however.
                                  >
                                  > Your center voltage at 3.14V seems a little high as well, but I
                                  doubt
                                  > that is the main problem.
                                  >
                                  > Please let us know what you find.
                                  > Terry
                                  >
                                  >
                                  > --- In softrock40@yahoogroups.com, "geoffrey_cottrell" <g3.xgc@>
                                  > wrote:
                                  > >
                                  > > Hi Terry
                                  > >
                                  > > --- In softrock40@yahoogroups.com, "Terry" <wb4jfi@> wrote:
                                  > > >
                                  > > > Sorry, to clarify the comment about U5 pins 1, 2, 3, 5, 6, 7
                                  all
                                  > > > reading 1/2 the regulator out: Those should ALL be DC voltage
                                  > > > readings.
                                  > > > Terry
                                  > > >
                                  > > >
                                  > >
                                  > > Following your logic, I have just checked the pins DC voltages of
                                  U8
                                  > > on the RXTX board. I guess analagous to U5 on SR40 RX. They are:
                                  > > pin 1 2.76V
                                  > > pin 2 3.14V
                                  > > pin 3 3.14V
                                  > > pin 4 0V
                                  > > pin 5 3.14V
                                  > > pin 6 3.1V
                                  > > pin 7 4.95V
                                  > > pin 8 4.95V
                                  > >
                                  > > The regulator volts is 4.98V.
                                  > >
                                  > > Seems that pin 7 is too high. No shorts between U8 pins.
                                  > >
                                  > > Any thoughts?
                                  > >
                                  > > 73
                                  > > Geoff
                                  > > G3XGC
                                  > >
                                  >
                                • geoffrey_cottrell
                                  Hi Terry Thanks for your help. I have just checked pins 7 and 8 again - there is definitely no short between them! Hmmmm ... curious! Geoff
                                  Message 16 of 27 , Apr 18, 2007
                                  • 0 Attachment
                                    Hi Terry

                                    Thanks for your help.

                                    I have just checked pins 7 and 8 again - there is definitely no short
                                    between them!

                                    Hmmmm ... curious!

                                    Geoff

                                    --- In softrock40@yahoogroups.com, "Terry" <wb4jfi@...> wrote:
                                    >
                                    > I found the email about shorrts on the RxTx boards. They were shorts
                                    > to ground, so that's probably not your problem. But, I would check
                                    > around pin 7 to make sure it is not shorted to VCC anyway. Double-
                                    > check with a meter, as a very thin short could occur, even under the
                                    > IC.
                                    > Terry
                                    >
                                    >
                                    > --- In softrock40@yahoogroups.com, "Terry" <wb4jfi@> wrote:
                                    > >
                                    > > It took me a while to find my RxTX schematics. I have a prototype
                                    > > RxTx built, but my production RxTx is still in kit form.
                                    > >
                                    > > You are correct, U8 on the RxTx would be similar to U5 on the SR
                                    > Lite.
                                    > >
                                    > > I would agree that U8, pin 7 seems high. Is it coincidental that
                                    > pin
                                    > > 7 is right next to supply voltage to U8 on pin 8? Can you double
                                    > > check with an ohm meter that pins 7 & 8 are not shorted? It could
                                    > > also be that U8 is defective, or many other possibilities around
                                    > > that. My guess is that your problem is right there in U8B (pins 5-
                                    > 7).
                                    > >
                                    > > In looking at my unbuild board, there does appear to be adequate
                                    > > separation of traces. I remember Tony mentioning that there was a
                                    > > problem on a limited number of PC boards for the RxTx, but I can't
                                    > > find the email about that right now. I don't think it was around
                                    > U8,
                                    > > however.
                                    > >
                                    > > Your center voltage at 3.14V seems a little high as well, but I
                                    > doubt
                                    > > that is the main problem.
                                    > >
                                    > > Please let us know what you find.
                                    > > Terry
                                    > >
                                    > >
                                    > > --- In softrock40@yahoogroups.com, "geoffrey_cottrell" <g3.xgc@>
                                    > > wrote:
                                    > > >
                                    > > > Hi Terry
                                    > > >
                                    > > > --- In softrock40@yahoogroups.com, "Terry" <wb4jfi@> wrote:
                                    > > > >
                                    > > > > Sorry, to clarify the comment about U5 pins 1, 2, 3, 5, 6, 7
                                    > all
                                    > > > > reading 1/2 the regulator out: Those should ALL be DC voltage
                                    > > > > readings.
                                    > > > > Terry
                                    > > > >
                                    > > > >
                                    > > >
                                    > > > Following your logic, I have just checked the pins DC voltages of
                                    > U8
                                    > > > on the RXTX board. I guess analagous to U5 on SR40 RX. They are:
                                    > > > pin 1 2.76V
                                    > > > pin 2 3.14V
                                    > > > pin 3 3.14V
                                    > > > pin 4 0V
                                    > > > pin 5 3.14V
                                    > > > pin 6 3.1V
                                    > > > pin 7 4.95V
                                    > > > pin 8 4.95V
                                    > > >
                                    > > > The regulator volts is 4.98V.
                                    > > >
                                    > > > Seems that pin 7 is too high. No shorts between U8 pins.
                                    > > >
                                    > > > Any thoughts?
                                    > > >
                                    > > > 73
                                    > > > Geoff
                                    > > > G3XGC
                                    > > >
                                    > >
                                    >
                                  • Len Warner
                                    ... If you compare RXTXv6.1 schematic sheet 2 12_27.pdf and v6.2 SoftRock Lite schematic 12_18.pdf you will see that the circuits are very nearly
                                    Message 17 of 27 , Apr 18, 2007
                                    • 0 Attachment
                                      At 08:41 07/04/18, Digest Number 1498 wrote:
                                      > Posted by: "geoffrey_cottrell" g3.xgc@... geoffrey_cottrell
                                      > Date: Wed Apr 18, 2007 12:31 am ((PDT))
                                      >
                                      >I should have mentioned that I have the RXTX 6.1 here.
                                      >[snip]
                                      >Do you know equivalent pin numbers for the RXTX?

                                      If you compare
                                      "RXTXv6.1 schematic sheet 2 12_27.pdf"
                                      and
                                      "v6.2 SoftRock Lite schematic 12_18.pdf"
                                      you will see that the circuits are very nearly identical,
                                      with the exception of the antenna filter and JP1 and JP2.

                                      All the major components are in the same place in both
                                      schematics, so it shouldn't be difficult to translate Terry's
                                      SR6.2 test points into SR6.1 Rx ones. If you begin to
                                      understand the circuit a little it should become obvious.

                                      (Yes, we should have separate diagnostic sheets - one day ;-)


                                      Regards, LenW
                                      --
                                      From Yahoo! Groups help: ... trim all the irrelevant quoted text out of
                                      your message
                                      (as a courtesy to the other members of the group to make the digest
                                      easier to read).
                                    • geoffrey_cottrell
                                      Len Thanks for that. I have compared the two circuits and noticed the similarity - hence my earlier post. As there is no measured short on pins 7 and 8 of U8,
                                      Message 18 of 27 , Apr 18, 2007
                                      • 0 Attachment
                                        Len

                                        Thanks for that. I have compared the two circuits and noticed the similarity - hence my
                                        earlier post. As there is no measured short on pins 7 and 8 of U8, am beginning to
                                        suspect a fault in the chip itself.

                                        Geoff

                                        --- In softrock40@yahoogroups.com, Len Warner <novost@...> wrote:
                                        >
                                        > At 08:41 07/04/18, Digest Number 1498 wrote:
                                        > > Posted by: "geoffrey_cottrell" g3.xgc@... geoffrey_cottrell
                                        > > Date: Wed Apr 18, 2007 12:31 am ((PDT))
                                        > >
                                        > >I should have mentioned that I have the RXTX 6.1 here.
                                        > >[snip]
                                        > >Do you know equivalent pin numbers for the RXTX?
                                        >
                                        > If you compare
                                        > "RXTXv6.1 schematic sheet 2 12_27.pdf"
                                        > and
                                        > "v6.2 SoftRock Lite schematic 12_18.pdf"
                                        > you will see that the circuits are very nearly identical,
                                        > with the exception of the antenna filter and JP1 and JP2.
                                        >
                                        > All the major components are in the same place in both
                                        > schematics, so it shouldn't be difficult to translate Terry's
                                        > SR6.2 test points into SR6.1 Rx ones. If you begin to
                                        > understand the circuit a little it should become obvious.
                                        >
                                        > (Yes, we should have separate diagnostic sheets - one day ;-)
                                        >
                                        >
                                        > Regards, LenW
                                        > --
                                        > From Yahoo! Groups help: ... trim all the irrelevant quoted text out of
                                        > your message
                                        > (as a courtesy to the other members of the group to make the digest
                                        > easier to read).
                                        >
                                      • geoffrey_cottrell
                                        To follow on - more events. It seems I was right - U8 was defective. Fortunately I had a second RXTX kit 40/30 that had just arrived and I replaced U8 in my
                                        Message 19 of 27 , Apr 18, 2007
                                        • 0 Attachment
                                          To follow on - more events. It seems I was right - U8 was defective.
                                          Fortunately I had a second RXTX kit 40/30 that had just arrived and I
                                          replaced U8 in my 160m version with a new one. Now getting credible
                                          outputs from tip and ring; the frequency of both follows the
                                          difference in frequency between sig gen and xtal; and they are 90
                                          degrees apart! Moreover the voltages are now 2.5 volts on the
                                          important pins of U8. So thank you Terry and Len for valuable
                                          comments. Now to test with an antenna!

                                          73
                                          Geoff
                                          G3XGC

                                          --- In softrock40@yahoogroups.com, "geoffrey_cottrell" <g3.xgc@...> wrote:
                                          >
                                          > Len
                                          >
                                          > Thanks for that. I have compared the two circuits and noticed the
                                          similarity - hence my
                                          > earlier post. As there is no measured short on pins 7 and 8 of U8,
                                          am beginning to
                                          > suspect a fault in the chip itself.
                                          >
                                          > Geoff
                                          >
                                          > --- In softrock40@yahoogroups.com, Len Warner <novost@> wrote:
                                          > >
                                          > > At 08:41 07/04/18, Digest Number 1498 wrote:
                                          > > > Posted by: "geoffrey_cottrell" g3.xgc@ geoffrey_cottrell
                                          > > > Date: Wed Apr 18, 2007 12:31 am ((PDT))
                                          > > >
                                          > > >I should have mentioned that I have the RXTX 6.1 here.
                                          > > >[snip]
                                          > > >Do you know equivalent pin numbers for the RXTX?
                                          > >
                                          > > If you compare
                                          > > "RXTXv6.1 schematic sheet 2 12_27.pdf"
                                          > > and
                                          > > "v6.2 SoftRock Lite schematic 12_18.pdf"
                                          > > you will see that the circuits are very nearly identical,
                                          > > with the exception of the antenna filter and JP1 and JP2.
                                          > >
                                          > > All the major components are in the same place in both
                                          > > schematics, so it shouldn't be difficult to translate Terry's
                                          > > SR6.2 test points into SR6.1 Rx ones. If you begin to
                                          > > understand the circuit a little it should become obvious.
                                          > >
                                          > > (Yes, we should have separate diagnostic sheets - one day ;-)
                                          > >
                                          > >
                                          > > Regards, LenW
                                          > > --
                                          > > From Yahoo! Groups help: ... trim all the irrelevant quoted
                                          text out of
                                          > > your message
                                          > > (as a courtesy to the other members of the group to make the
                                          digest
                                          > > easier to read).
                                          > >
                                          >
                                        • Terry
                                          Congrats Geoff!! May your antenna be strong, and your SDR receive great! Terry ... defective. ... I
                                          Message 20 of 27 , Apr 18, 2007
                                          • 0 Attachment
                                            Congrats Geoff!! May your antenna be strong, and your SDR receive
                                            great!
                                            Terry


                                            --- In softrock40@yahoogroups.com, "geoffrey_cottrell" <g3.xgc@...>
                                            wrote:
                                            >
                                            > To follow on - more events. It seems I was right - U8 was
                                            defective.
                                            > Fortunately I had a second RXTX kit 40/30 that had just arrived and
                                            I
                                            > replaced U8 in my 160m version with a new one. Now getting credible
                                            > outputs from tip and ring; the frequency of both follows the
                                            > difference in frequency between sig gen and xtal; and they are 90
                                            > degrees apart! Moreover the voltages are now 2.5 volts on the
                                            > important pins of U8. So thank you Terry and Len for valuable
                                            > comments. Now to test with an antenna!
                                            >
                                            > 73
                                            > Geoff
                                            > G3XGC
                                            >
                                            > --- In softrock40@yahoogroups.com, "geoffrey_cottrell" <g3.xgc@>
                                            wrote:
                                            > >
                                            > > Len
                                            > >
                                            > > Thanks for that. I have compared the two circuits and noticed the
                                            > similarity - hence my
                                            > > earlier post. As there is no measured short on pins 7 and 8 of U8,
                                            > am beginning to
                                            > > suspect a fault in the chip itself.
                                            > >
                                            > > Geoff
                                            > >
                                            > > --- In softrock40@yahoogroups.com, Len Warner <novost@> wrote:
                                            > > >
                                            > > > At 08:41 07/04/18, Digest Number 1498 wrote:
                                            > > > > Posted by: "geoffrey_cottrell" g3.xgc@ geoffrey_cottrell
                                            > > > > Date: Wed Apr 18, 2007 12:31 am ((PDT))
                                            > > > >
                                            > > > >I should have mentioned that I have the RXTX 6.1 here.
                                            > > > >[snip]
                                            > > > >Do you know equivalent pin numbers for the RXTX?
                                            > > >
                                            > > > If you compare
                                            > > > "RXTXv6.1 schematic sheet 2 12_27.pdf"
                                            > > > and
                                            > > > "v6.2 SoftRock Lite schematic 12_18.pdf"
                                            > > > you will see that the circuits are very nearly identical,
                                            > > > with the exception of the antenna filter and JP1 and JP2.
                                            > > >
                                            > > > All the major components are in the same place in both
                                            > > > schematics, so it shouldn't be difficult to translate Terry's
                                            > > > SR6.2 test points into SR6.1 Rx ones. If you begin to
                                            > > > understand the circuit a little it should become obvious.
                                            > > >
                                            > > > (Yes, we should have separate diagnostic sheets - one day ;-)
                                            > > >
                                            > > >
                                            > > > Regards, LenW
                                            > > > --
                                            > > > From Yahoo! Groups help: ... trim all the irrelevant quoted
                                            > text out of
                                            > > > your message
                                            > > > (as a courtesy to the other members of the group to make the
                                            > digest
                                            > > > easier to read).
                                            > > >
                                            > >
                                            >
                                          • Dave Mynatt
                                            A basic question for the experts in our group; Does everyone have a special QSL card made for their call sign? I ve been looking at the ones for sale and see
                                            Message 21 of 27 , Apr 18, 2007
                                            • 0 Attachment
                                              A basic question for the experts in our group; Does everyone have a 'special' QSL card made for their call sign? I've been looking at the ones for sale and see some neat ones, and I can design my own, but is that something our hobby does as a matter of course?
                                               
                                               
                                               
                                               
                                               
                                               
                                               
                                               
                                              ----- Original Message -----
                                              From: Terry
                                              Sent: Wednesday, April 18, 2007 2:42 PM
                                              Subject: [softrock40] Re: Removing mirror image signals

                                              Congrats Geoff!! May your antenna be strong, and your SDR receive
                                              great!
                                              Terry

                                              --- In softrock40@yahoogro ups.com, "geoffrey_cottrell" <g3.xgc@...>
                                              wrote:
                                              >
                                              > To follow on - more events. It seems I was right - U8 was
                                              defective.
                                              > Fortunately I had a second RXTX kit 40/30 that had just arrived and
                                              I
                                              > replaced U8 in my 160m version with a new one. Now getting credible
                                              > outputs from tip and ring; the frequency of both follows the
                                              > difference in frequency between sig gen and xtal; and they are 90
                                              > degrees apart! Moreover the voltages are now 2.5 volts on the
                                              > important pins of U8. So thank you Terry and Len for valuable
                                              > comments. Now to test with an antenna!
                                              >
                                              > 73
                                              > Geoff
                                              > G3XGC
                                              >
                                              > --- In softrock40@yahoogro ups.com, "geoffrey_cottrell" <g3.xgc@>
                                              wrote:
                                              > >
                                              > > Len
                                              > >
                                              > > Thanks for that. I have compared the two circuits and noticed the
                                              > similarity - hence my
                                              > > earlier post. As there is no measured short on pins 7 and 8 of U8,
                                              > am beginning to
                                              > > suspect a fault in the chip itself.
                                              > >
                                              > > Geoff
                                              > >
                                              > > --- In softrock40@yahoogro ups.com, Len Warner <novost@> wrote:
                                              > > >
                                              > > > At 08:41 07/04/18, Digest Number 1498 wrote:
                                              > > > > Posted by: "geoffrey_cottrell" g3.xgc@ geoffrey_cottrell
                                              > > > > Date: Wed Apr 18, 2007 12:31 am ((PDT))
                                              > > > >
                                              > > > >I should have mentioned that I have the RXTX 6.1 here.
                                              > > > >[snip]
                                              > > > >Do you know equivalent pin numbers for the RXTX?
                                              > > >
                                              > > > If you compare
                                              > > > "RXTXv6.1 schematic sheet 2 12_27.pdf"
                                              > > > and
                                              > > > "v6.2 SoftRock Lite schematic 12_18.pdf"
                                              > > > you will see that the circuits are very nearly identical,
                                              > > > with the exception of the antenna filter and JP1 and JP2.
                                              > > >
                                              > > > All the major components are in the same place in both
                                              > > > schematics, so it shouldn't be difficult to translate Terry's
                                              > > > SR6.2 test points into SR6.1 Rx ones. If you begin to
                                              > > > understand the circuit a little it should become obvious.
                                              > > >
                                              > > > (Yes, we should have separate diagnostic sheets - one day ;-)
                                              > > >
                                              > > >
                                              > > > Regards, LenW
                                              > > > --
                                              > > > From Yahoo! Groups help: ... trim all the irrelevant quoted
                                              > text out of
                                              > > > your message
                                              > > > (as a courtesy to the other members of the group to make the
                                              > digest
                                              > > > easier to read).
                                              > > >
                                              > >
                                              >

                                            • Tony Parks
                                              Hi Geoff and others, Any missing or defective component in a SoftRock Lite or RXTXvt6.1 kit will be replaced a no charge to the kit buyer. Just send me a
                                              Message 22 of 27 , Apr 18, 2007
                                              • 0 Attachment
                                                Hi Geoff and others,
                                                 
                                                Any missing or defective component in a SoftRock Lite or RXTXvt6.1 kit will be replaced a no charge to the kit buyer.  Just send me a brief e-mail on what part or parts are needed and include your mailing address where you want the parts sent.
                                                 
                                                Glad to hear the RX portion seems to be operating properly.
                                                 
                                                73,
                                                Tony KB9YIG
                                                 
                                                ----- Original Message -----
                                                Sent: Wednesday, April 18, 2007 4:34 PM
                                                Subject: [softrock40] Re: Removing mirror image signals

                                                To follow on - more events. It seems I was right - U8 was defective.
                                                Fortunately I had a second RXTX kit 40/30 that had just arrived and I
                                                replaced U8 in my 160m version with a new one. Now getting credible
                                                outputs from tip and ring; the frequency of both follows the
                                                difference in frequency between sig gen and xtal; and they are 90
                                                degrees apart! Moreover the voltages are now 2.5 volts on the
                                                important pins of U8. So thank you Terry and Len for valuable
                                                comments. Now to test with an antenna!

                                                73
                                                Geoff
                                                G3XGC

                                                --- In softrock40@yahoogro ups.com, "geoffrey_cottrell" <g3.xgc@...> wrote:
                                                >
                                                > Len
                                                >
                                                > Thanks for that. I have compared the two circuits and noticed the
                                                similarity - hence my
                                                > earlier post. As there is no measured short on pins 7 and 8 of U8,
                                                am beginning to
                                                > suspect a fault in the chip itself.
                                                >
                                                > Geoff
                                                >
                                                > --- In softrock40@yahoogro ups.com, Len Warner <novost@> wrote:
                                                > >
                                                > > At 08:41 07/04/18, Digest Number 1498 wrote:
                                                > > > Posted by: "geoffrey_cottrell" g3.xgc@ geoffrey_cottrell
                                                > > > Date: Wed Apr 18, 2007 12:31 am ((PDT))
                                                > > >
                                                > > >I should have mentioned that I have the RXTX 6.1 here.
                                                > > >[snip]
                                                > > >Do you know equivalent pin numbers for the RXTX?
                                                > >
                                                > > If you compare
                                                > > "RXTXv6.1 schematic sheet 2 12_27.pdf"
                                                > > and
                                                > > "v6.2 SoftRock Lite schematic 12_18.pdf"
                                                > > you will see that the circuits are very nearly identical,
                                                > > with the exception of the antenna filter and JP1 and JP2.
                                                > >
                                                > > All the major components are in the same place in both
                                                > > schematics, so it shouldn't be difficult to translate Terry's
                                                > > SR6.2 test points into SR6.1 Rx ones. If you begin to
                                                > > understand the circuit a little it should become obvious.
                                                > >
                                                > > (Yes, we should have separate diagnostic sheets - one day ;-)
                                                > >
                                                > >
                                                > > Regards, LenW
                                                > > --
                                                > > From Yahoo! Groups help: ... trim all the irrelevant quoted
                                                text out of
                                                > > your message
                                                > > (as a courtesy to the other members of the group to make the
                                                digest
                                                > > easier to read).
                                                > >
                                                >

                                              • Tim Folkenson
                                                Overnightprints.com has plenty of generic options you could use to design your card online if you want to go custom without too much work. 1000 full color 4 x
                                                Message 23 of 27 , Apr 18, 2007
                                                • 0 Attachment
                                                  Overnightprints.com has plenty of generic options you could use to
                                                  design your card online if you want to go custom without too much
                                                  work. 1000 full color 4 x 6 cards are $99 last time I checked. I use
                                                  them for Real Estate and they come out great.

                                                  Tim

                                                  --- In softrock40@yahoogroups.com, "Dave Mynatt" <dave@...> wrote:
                                                  >
                                                  > A basic question for the experts in our group; Does everyone have
                                                  a 'special' QSL card made for their call sign? I've been looking at
                                                  the ones for sale and see some neat ones, and I can design my own,
                                                  but is that something our hobby does as a matter of course?
                                                  >
                                                  >
                                                  >
                                                  >
                                                  >
                                                  >
                                                  >
                                                  >
                                                  > ----- Original Message -----
                                                  > From: Terry
                                                  > To: softrock40@yahoogroups.com
                                                  > Sent: Wednesday, April 18, 2007 2:42 PM
                                                  > Subject: [softrock40] Re: Removing mirror image signals
                                                  >
                                                  >
                                                  > Congrats Geoff!! May your antenna be strong, and your SDR receive
                                                  > great!
                                                  > Terry
                                                  >
                                                  > --- In softrock40@yahoogroups.com, "geoffrey_cottrell" <g3.xgc@>
                                                  > wrote:
                                                  > >
                                                  > > To follow on - more events. It seems I was right - U8 was
                                                  > defective.
                                                  > > Fortunately I had a second RXTX kit 40/30 that had just arrived
                                                  and
                                                  > I
                                                  > > replaced U8 in my 160m version with a new one. Now getting
                                                  credible
                                                  > > outputs from tip and ring; the frequency of both follows the
                                                  > > difference in frequency between sig gen and xtal; and they are
                                                  90
                                                  > > degrees apart! Moreover the voltages are now 2.5 volts on the
                                                  > > important pins of U8. So thank you Terry and Len for valuable
                                                  > > comments. Now to test with an antenna!
                                                  > >
                                                  > > 73
                                                  > > Geoff
                                                  > > G3XGC
                                                  > >
                                                  > > --- In softrock40@yahoogroups.com, "geoffrey_cottrell"
                                                  <g3.xgc@>
                                                  > wrote:
                                                  > > >
                                                  > > > Len
                                                  > > >
                                                  > > > Thanks for that. I have compared the two circuits and noticed
                                                  the
                                                  > > similarity - hence my
                                                  > > > earlier post. As there is no measured short on pins 7 and 8
                                                  of U8,
                                                  > > am beginning to
                                                  > > > suspect a fault in the chip itself.
                                                  > > >
                                                  > > > Geoff
                                                  > > >
                                                  > > > --- In softrock40@yahoogroups.com, Len Warner <novost@> wrote:
                                                  > > > >
                                                  > > > > At 08:41 07/04/18, Digest Number 1498 wrote:
                                                  > > > > > Posted by: "geoffrey_cottrell" g3.xgc@ geoffrey_cottrell
                                                  > > > > > Date: Wed Apr 18, 2007 12:31 am ((PDT))
                                                  > > > > >
                                                  > > > > >I should have mentioned that I have the RXTX 6.1 here.
                                                  > > > > >[snip]
                                                  > > > > >Do you know equivalent pin numbers for the RXTX?
                                                  > > > >
                                                  > > > > If you compare
                                                  > > > > "RXTXv6.1 schematic sheet 2 12_27.pdf"
                                                  > > > > and
                                                  > > > > "v6.2 SoftRock Lite schematic 12_18.pdf"
                                                  > > > > you will see that the circuits are very nearly identical,
                                                  > > > > with the exception of the antenna filter and JP1 and JP2.
                                                  > > > >
                                                  > > > > All the major components are in the same place in both
                                                  > > > > schematics, so it shouldn't be difficult to translate
                                                  Terry's
                                                  > > > > SR6.2 test points into SR6.1 Rx ones. If you begin to
                                                  > > > > understand the circuit a little it should become obvious.
                                                  > > > >
                                                  > > > > (Yes, we should have separate diagnostic sheets - one day ;-
                                                  )
                                                  > > > >
                                                  > > > >
                                                  > > > > Regards, LenW
                                                  > > > > --
                                                  > > > > From Yahoo! Groups help: ... trim all the irrelevant quoted
                                                  > > text out of
                                                  > > > > your message
                                                  > > > > (as a courtesy to the other members of the group to make the
                                                  > > digest
                                                  > > > > easier to read).
                                                  > > > >
                                                  > > >
                                                  > >
                                                  >
                                                • ian mcphedran
                                                  That s really encouraging. I have exactly the same symptoms on mine and deduced that U8 is faulty (definitely no shorts). Tony is sending a replacement and in
                                                  Message 24 of 27 , Apr 19, 2007
                                                  • 0 Attachment
                                                    That's really encouraging. I have exactly the same symptoms on mine and deduced that U8 is faulty (definitely no shorts). Tony is sending a replacement and in the meantime I have removed the ic and confirm no shorts underneath.
                                                    Enjoy your TX/RX
                                                    Ian GM3GTQ

                                                    geoffrey_cottrell <g3.xgc@...> wrote:
                                                    To follow on - more events. It seems I was right - U8 was defective.
                                                    Fortunately I had a second RXTX kit 40/30 that had just arrived and I
                                                    replaced U8 in my 160m version with a new one. Now getting credible
                                                    outputs from tip and ring; the frequency of both follows the
                                                    difference in frequency between sig gen and xtal; and they are 90
                                                    degrees apart! Moreover the voltages are now 2.5 volts on the
                                                    important pins of U8. So thank you Terry and Len for valuable
                                                    comments. Now to test with an antenna!

                                                    73
                                                    Geoff
                                                    G3XGC

                                                    --- In softrock40@yahoogro ups.com, "geoffrey_cottrell" <g3.xgc@...> wrote:
                                                    >
                                                    > Len
                                                    >
                                                    > Thanks for that. I have compared the two circuits and noticed the
                                                    similarity - hence my
                                                    > earlier post. As there is no measured short on pins 7 and 8 of U8,
                                                    am beginning to
                                                    > suspect a fault in the chip itself.
                                                    >
                                                    > Geoff
                                                    >
                                                    > --- In softrock40@yahoogro ups.com, Len Warner <novost@> wrote:
                                                    > >
                                                    > > At 08:41 07/04/18, Digest Number 1498 wrote:
                                                    > > > Posted by: "geoffrey_cottrell" g3.xgc@ geoffrey_cottrell
                                                    > > > Date: Wed Apr 18, 2007 12:31 am ((PDT))
                                                    > > >
                                                    > > >I should have mentioned that I have the RXTX 6.1 here.
                                                    > > >[snip]
                                                    > > >Do you know equivalent pin numbers for the RXTX?
                                                    > >
                                                    > > If you compare
                                                    > > "RXTXv6.1 schematic sheet 2 12_27.pdf"
                                                    > > and
                                                    > > "v6.2 SoftRock Lite schematic 12_18.pdf"
                                                    > > you will see that the circuits are very nearly identical,
                                                    > > with the exception of the antenna filter and JP1 and JP2.
                                                    > >
                                                    > > All the major components are in the same place in both
                                                    > > schematics, so it shouldn't be difficult to translate Terry's
                                                    > > SR6.2 test points into SR6.1 Rx ones. If you begin to
                                                    > > understand the circuit a little it should become obvious.
                                                    > >
                                                    > > (Yes, we should have separate diagnostic sheets - one day ;-)
                                                    > >
                                                    > >
                                                    > > Regards, LenW
                                                    > > --
                                                    > > From Yahoo! Groups help: ... trim all the irrelevant quoted
                                                    text out of
                                                    > > your message
                                                    > > (as a courtesy to the other members of the group to make the
                                                    digest
                                                    > > easier to read).
                                                    > >
                                                    >



                                                    Yahoo! Mail is the world's favourite email. Don't settle for less, sign up for your free account today.

                                                  • Russell Blair
                                                    Terry, I have been trying to keep up with this thread of e-mails, I have been using Rocky3.0 as the software to RX on the SR-40 40m/30m board. Now with
                                                    Message 25 of 27 , Apr 19, 2007
                                                    • 0 Attachment
                                                      Terry, I have been trying to keep up with this thread
                                                      of e-mails, I have been using Rocky3.0 as the software
                                                      to RX on the SR-40 40m/30m board. Now with Rocky3.0 my
                                                      Lo is 10.125 Khz, I move the Lo (10.125 Khz 30m)to the
                                                      center of the window, now I'm able to see the low side
                                                      and the high side of the Lo (10.100---10.125---10.150)
                                                      +/- a few Khz.

                                                      Now if that RTTY station that has a strong signal I
                                                      can see him on both sides of the Lo, but this is not
                                                      true for all stations, there are some stations on cw
                                                      on the low side that are not on the upper side or they
                                                      are supprested. I cant say this is true for 40m.

                                                      So from all the e-mails I take it that I should not be
                                                      seeing the same station on both sides ?, I will go
                                                      back and check my voltage readings on U8 and see what
                                                      I have. My sound card is the Sound Blaster Live and I
                                                      only have one card installed in the PC.

                                                      Tnx Russell NC5O
                                                      --- Terry <wb4jfi@...> wrote:

                                                      > Congrats Geoff!! May your antenna be strong, and
                                                      > your SDR receive
                                                      > great!
                                                      > Terry
                                                      >
                                                      >
                                                      > --- In softrock40@yahoogroups.com,
                                                      > "geoffrey_cottrell" <g3.xgc@...>
                                                      > wrote:
                                                      > >
                                                      > > To follow on - more events. It seems I was right
                                                      > - U8 was
                                                      > defective.
                                                      > > Fortunately I had a second RXTX kit 40/30 that had
                                                      > just arrived and
                                                      > I
                                                      > > replaced U8 in my 160m version with a new one.
                                                      > Now getting credible
                                                      > > outputs from tip and ring; the frequency of both
                                                      > follows the
                                                      > > difference in frequency between sig gen and xtal;
                                                      > and they are 90
                                                      > > degrees apart! Moreover the voltages are now 2.5
                                                      > volts on the
                                                      > > important pins of U8. So thank you Terry and Len
                                                      > for valuable
                                                      > > comments. Now to test with an antenna!
                                                      > >
                                                      > > 73
                                                      > > Geoff
                                                      > > G3XGC
                                                      > >
                                                      > > --- In softrock40@yahoogroups.com,
                                                      > "geoffrey_cottrell" <g3.xgc@>
                                                      > wrote:
                                                      > > >
                                                      > > > Len
                                                      > > >
                                                      > > > Thanks for that. I have compared the two
                                                      > circuits and noticed the
                                                      > > similarity - hence my
                                                      > > > earlier post. As there is no measured short on
                                                      > pins 7 and 8 of U8,
                                                      > > am beginning to
                                                      > > > suspect a fault in the chip itself.
                                                      > > >
                                                      > > > Geoff
                                                      > > >
                                                      > > > --- In softrock40@yahoogroups.com, Len Warner
                                                      > <novost@> wrote:
                                                      > > > >
                                                      > > > > At 08:41 07/04/18, Digest Number 1498 wrote:
                                                      > > > > > Posted by: "geoffrey_cottrell" g3.xgc@
                                                      > geoffrey_cottrell
                                                      > > > > > Date: Wed Apr 18, 2007 12:31 am ((PDT))
                                                      > > > > >
                                                      > > > > >I should have mentioned that I have the RXTX
                                                      > 6.1 here.
                                                      > > > > >[snip]
                                                      > > > > >Do you know equivalent pin numbers for the
                                                      > RXTX?
                                                      > > > >
                                                      > > > > If you compare
                                                      > > > > "RXTXv6.1 schematic sheet 2 12_27.pdf"
                                                      > > > > and
                                                      > > > > "v6.2 SoftRock Lite schematic 12_18.pdf"
                                                      > > > > you will see that the circuits are very nearly
                                                      > identical,
                                                      > > > > with the exception of the antenna filter and
                                                      > JP1 and JP2.
                                                      > > > >
                                                      > > > > All the major components are in the same place
                                                      > in both
                                                      > > > > schematics, so it shouldn't be difficult to
                                                      > translate Terry's
                                                      > > > > SR6.2 test points into SR6.1 Rx ones. If you
                                                      > begin to
                                                      > > > > understand the circuit a little it should
                                                      > become obvious.
                                                      > > > >
                                                      > > > > (Yes, we should have separate diagnostic
                                                      > sheets - one day ;-)
                                                      > > > >
                                                      > > > >
                                                      > > > > Regards, LenW
                                                      > > > > --
                                                      > > > > From Yahoo! Groups help: ... trim all the
                                                      > irrelevant quoted
                                                      > > text out of
                                                      > > > > your message
                                                      > > > > (as a courtesy to the other members of the
                                                      > group to make the
                                                      > > digest
                                                      > > > > easier to read).
                                                      > > > >
                                                      > > >
                                                      > >
                                                      >
                                                      >
                                                      >


                                                      =================
                                                      IN GOD WE TRUST !
                                                      =================
                                                      Russell Blair
                                                      QTH ========= Richardson Tx
                                                      CALL ========= NC5O
                                                      GRID ========= EM12px
                                                      FH# ========== 300
                                                      DOS# ========= 470
                                                      =================

                                                      __________________________________________________
                                                      Do You Yahoo!?
                                                      Tired of spam? Yahoo! Mail has the best spam protection around
                                                      http://mail.yahoo.com
                                                    • Terry
                                                      If you have some signals that show up on only one side of center freq, then the SoftRock and Rocky are probably working right (as a guess from me).
                                                      Message 26 of 27 , Apr 19, 2007
                                                      • 0 Attachment
                                                        If you have some signals that show up on only one side of center
                                                        freq, then the SoftRock and Rocky are "probably" working right (as a
                                                        guess from me). Especially if the single frequency signals are of a
                                                        higher level on the display, it is probably OK.

                                                        There is a finite amount of image rejection that occurs, and many
                                                        things affect the extent of rejection. As you get near the edges of
                                                        the reveive bandwidth, the sound card performance could be poorer.
                                                        The IQ calibration only happens at the frequency you run it at, as
                                                        you move away from that frequency, image rejection changes.

                                                        A very strong signal may show up on both sides of center freq. For
                                                        example, I just setup a SR Lite & Rocky 1.5. I fed in a signal and
                                                        reset the IQ balance with a strong signal near the lower edge of the
                                                        receive band, and get over 60dB image rejection. However, when I
                                                        tune the signal generator to near the center frequency, I get only
                                                        about 30dB image rejection.

                                                        If you have a scope (or maybe just a Windows audio program), you
                                                        should verify that there is audio on both the left and right channels
                                                        going into the sound card, and at near the same level. If the
                                                        two "audio" dignals (actually a low IF) are near the same level, the
                                                        hardware is probably working right. With a scope, you could verify
                                                        that one sine wave is about 90-degrees delayed from the other. Try
                                                        to do this at a frequency that is closer to the center frequency
                                                        hump, as the IF frequency will be lower, and easier to see.

                                                        <legal biolerplate>
                                                        This is a simplification, and based on some assumptions that I cannot
                                                        comletely verify due to the remote nature of this correspondance.
                                                        Your mileage may vary. No warranty expressed or implied. Done.
                                                        </legal boilerplate>

                                                        Hope that helps.
                                                        Terry



                                                        --- In softrock40@yahoogroups.com, Russell Blair
                                                        <russell_blair86@...> wrote:
                                                        >
                                                        > Terry, I have been trying to keep up with this thread
                                                        > of e-mails, I have been using Rocky3.0 as the software
                                                        > to RX on the SR-40 40m/30m board. Now with Rocky3.0 my
                                                        > Lo is 10.125 Khz, I move the Lo (10.125 Khz 30m)to the
                                                        > center of the window, now I'm able to see the low side
                                                        > and the high side of the Lo (10.100---10.125---10.150)
                                                        > +/- a few Khz.
                                                        >
                                                        > Now if that RTTY station that has a strong signal I
                                                        > can see him on both sides of the Lo, but this is not
                                                        > true for all stations, there are some stations on cw
                                                        > on the low side that are not on the upper side or they
                                                        > are supprested. I cant say this is true for 40m.
                                                        >
                                                        > So from all the e-mails I take it that I should not be
                                                        > seeing the same station on both sides ?, I will go
                                                        > back and check my voltage readings on U8 and see what
                                                        > I have. My sound card is the Sound Blaster Live and I
                                                        > only have one card installed in the PC.
                                                        >
                                                        > Tnx Russell NC5O
                                                        > --- Terry <wb4jfi@...> wrote:
                                                        >
                                                        > > Congrats Geoff!! May your antenna be strong, and
                                                        > > your SDR receive
                                                        > > great!
                                                        > > Terry
                                                        > >
                                                        > >
                                                        > > --- In softrock40@yahoogroups.com,
                                                        > > "geoffrey_cottrell" <g3.xgc@>
                                                        > > wrote:
                                                        > > >
                                                        > > > To follow on - more events. It seems I was right
                                                        > > - U8 was
                                                        > > defective.
                                                        > > > Fortunately I had a second RXTX kit 40/30 that had
                                                        > > just arrived and
                                                        > > I
                                                        > > > replaced U8 in my 160m version with a new one.
                                                        > > Now getting credible
                                                        > > > outputs from tip and ring; the frequency of both
                                                        > > follows the
                                                        > > > difference in frequency between sig gen and xtal;
                                                        > > and they are 90
                                                        > > > degrees apart! Moreover the voltages are now 2.5
                                                        > > volts on the
                                                        > > > important pins of U8. So thank you Terry and Len
                                                        > > for valuable
                                                        > > > comments. Now to test with an antenna!
                                                        > > >
                                                        > > > 73
                                                        > > > Geoff
                                                        > > > G3XGC
                                                        > > >
                                                        > > > --- In softrock40@yahoogroups.com,
                                                        > > "geoffrey_cottrell" <g3.xgc@>
                                                        > > wrote:
                                                        > > > >
                                                        > > > > Len
                                                        > > > >
                                                        > > > > Thanks for that. I have compared the two
                                                        > > circuits and noticed the
                                                        > > > similarity - hence my
                                                        > > > > earlier post. As there is no measured short on
                                                        > > pins 7 and 8 of U8,
                                                        > > > am beginning to
                                                        > > > > suspect a fault in the chip itself.
                                                        > > > >
                                                        > > > > Geoff
                                                        > > > >
                                                        > > > > --- In softrock40@yahoogroups.com, Len Warner
                                                        > > <novost@> wrote:
                                                        > > > > >
                                                        > > > > > At 08:41 07/04/18, Digest Number 1498 wrote:
                                                        > > > > > > Posted by: "geoffrey_cottrell" g3.xgc@
                                                        > > geoffrey_cottrell
                                                        > > > > > > Date: Wed Apr 18, 2007 12:31 am ((PDT))
                                                        > > > > > >
                                                        > > > > > >I should have mentioned that I have the RXTX
                                                        > > 6.1 here.
                                                        > > > > > >[snip]
                                                        > > > > > >Do you know equivalent pin numbers for the
                                                        > > RXTX?
                                                        > > > > >
                                                        > > > > > If you compare
                                                        > > > > > "RXTXv6.1 schematic sheet 2 12_27.pdf"
                                                        > > > > > and
                                                        > > > > > "v6.2 SoftRock Lite schematic 12_18.pdf"
                                                        > > > > > you will see that the circuits are very nearly
                                                        > > identical,
                                                        > > > > > with the exception of the antenna filter and
                                                        > > JP1 and JP2.
                                                        > > > > >
                                                        > > > > > All the major components are in the same place
                                                        > > in both
                                                        > > > > > schematics, so it shouldn't be difficult to
                                                        > > translate Terry's
                                                        > > > > > SR6.2 test points into SR6.1 Rx ones. If you
                                                        > > begin to
                                                        > > > > > understand the circuit a little it should
                                                        > > become obvious.
                                                        > > > > >
                                                        > > > > > (Yes, we should have separate diagnostic
                                                        > > sheets - one day ;-)
                                                        > > > > >
                                                        > > > > >
                                                        > > > > > Regards, LenW
                                                        > > > > > --
                                                        > > > > > From Yahoo! Groups help: ... trim all the
                                                        > > irrelevant quoted
                                                        > > > text out of
                                                        > > > > > your message
                                                        > > > > > (as a courtesy to the other members of the
                                                        > > group to make the
                                                        > > > digest
                                                        > > > > > easier to read).
                                                        > > > > >
                                                        > > > >
                                                        > > >
                                                        > >
                                                        > >
                                                        > >
                                                        >
                                                        >
                                                        > =================
                                                        > IN GOD WE TRUST !
                                                        > =================
                                                        > Russell Blair
                                                        > QTH ========= Richardson Tx
                                                        > CALL ========= NC5O
                                                        > GRID ========= EM12px
                                                        > FH# ========== 300
                                                        > DOS# ========= 470
                                                        > =================
                                                        >
                                                        > __________________________________________________
                                                        > Do You Yahoo!?
                                                        > Tired of spam? Yahoo! Mail has the best spam protection around
                                                        > http://mail.yahoo.com
                                                        >
                                                      • Russell Blair
                                                        Tnx Terry, The RTTY signal is close to the Lo frequency, and that no other mirror image are seen on eather side of the Lo, I would think I m OK. I also try to
                                                        Message 27 of 27 , Apr 19, 2007
                                                        • 0 Attachment
                                                          Tnx Terry, The RTTY signal is close to the Lo
                                                          frequency, and that no other mirror image are seen on
                                                          eather side of the Lo, I would think I'm OK. I also
                                                          try to check other station locations from the Lo in
                                                          Khz and then check the other side of the Lo at the
                                                          same Khz and see if I see a signal. 95% of the time
                                                          it's not there, Only that RTTY station thats on 30m
                                                          not a Ham station.

                                                          Tnx Russell NC5O


                                                          --- Terry <wb4jfi@...> wrote:

                                                          > If you have some signals that show up on only one
                                                          > side of center
                                                          > freq, then the SoftRock and Rocky are "probably"
                                                          > working right (as a
                                                          > guess from me). Especially if the single frequency
                                                          > signals are of a
                                                          > higher level on the display, it is probably OK.
                                                          >
                                                          > There is a finite amount of image rejection that
                                                          > occurs, and many
                                                          > things affect the extent of rejection. As you get
                                                          > near the edges of
                                                          > the reveive bandwidth, the sound card performance
                                                          > could be poorer.
                                                          > The IQ calibration only happens at the frequency you
                                                          > run it at, as
                                                          > you move away from that frequency, image rejection
                                                          > changes.
                                                          >
                                                          > A very strong signal may show up on both sides of
                                                          > center freq. For
                                                          > example, I just setup a SR Lite & Rocky 1.5. I fed
                                                          > in a signal and
                                                          > reset the IQ balance with a strong signal near the
                                                          > lower edge of the
                                                          > receive band, and get over 60dB image rejection.
                                                          > However, when I
                                                          > tune the signal generator to near the center
                                                          > frequency, I get only
                                                          > about 30dB image rejection.
                                                          >
                                                          > If you have a scope (or maybe just a Windows audio
                                                          > program), you
                                                          > should verify that there is audio on both the left
                                                          > and right channels
                                                          > going into the sound card, and at near the same
                                                          > level. If the
                                                          > two "audio" dignals (actually a low IF) are near the
                                                          > same level, the
                                                          > hardware is probably working right. With a scope,
                                                          > you could verify
                                                          > that one sine wave is about 90-degrees delayed from
                                                          > the other. Try
                                                          > to do this at a frequency that is closer to the
                                                          > center frequency
                                                          > hump, as the IF frequency will be lower, and easier
                                                          > to see.
                                                          >
                                                          > <legal biolerplate>
                                                          > This is a simplification, and based on some
                                                          > assumptions that I cannot
                                                          > comletely verify due to the remote nature of this
                                                          > correspondance.
                                                          > Your mileage may vary. No warranty expressed or
                                                          > implied. Done.
                                                          > </legal boilerplate>
                                                          >
                                                          > Hope that helps.
                                                          > Terry
                                                          >
                                                          >
                                                          >
                                                          > --- In softrock40@yahoogroups.com, Russell Blair
                                                          > <russell_blair86@...> wrote:
                                                          > >
                                                          > > Terry, I have been trying to keep up with this
                                                          > thread
                                                          > > of e-mails, I have been using Rocky3.0 as the
                                                          > software
                                                          > > to RX on the SR-40 40m/30m board. Now with
                                                          > Rocky3.0 my
                                                          > > Lo is 10.125 Khz, I move the Lo (10.125 Khz 30m)to
                                                          > the
                                                          > > center of the window, now I'm able to see the low
                                                          > side
                                                          > > and the high side of the Lo
                                                          > (10.100---10.125---10.150)
                                                          > > +/- a few Khz.
                                                          > >
                                                          > > Now if that RTTY station that has a strong signal
                                                          > I
                                                          > > can see him on both sides of the Lo, but this is
                                                          > not
                                                          > > true for all stations, there are some stations on
                                                          > cw
                                                          > > on the low side that are not on the upper side or
                                                          > they
                                                          > > are supprested. I cant say this is true for 40m.
                                                          > >
                                                          > > So from all the e-mails I take it that I should
                                                          > not be
                                                          > > seeing the same station on both sides ?, I will go
                                                          > > back and check my voltage readings on U8 and see
                                                          > what
                                                          > > I have. My sound card is the Sound Blaster Live
                                                          > and I
                                                          > > only have one card installed in the PC.
                                                          > >
                                                          > > Tnx Russell NC5O
                                                          > > --- Terry <wb4jfi@...> wrote:
                                                          > >
                                                          > > > Congrats Geoff!! May your antenna be strong,
                                                          > and
                                                          > > > your SDR receive
                                                          > > > great!
                                                          > > > Terry
                                                          > > >
                                                          > > >
                                                          > > > --- In softrock40@yahoogroups.com,
                                                          > > > "geoffrey_cottrell" <g3.xgc@>
                                                          > > > wrote:
                                                          > > > >
                                                          > > > > To follow on - more events. It seems I was
                                                          > right
                                                          > > > - U8 was
                                                          > > > defective.
                                                          > > > > Fortunately I had a second RXTX kit 40/30 that
                                                          > had
                                                          > > > just arrived and
                                                          > > > I
                                                          > > > > replaced U8 in my 160m version with a new one.
                                                          >
                                                          > > > Now getting credible
                                                          > > > > outputs from tip and ring; the frequency of
                                                          > both
                                                          > > > follows the
                                                          > > > > difference in frequency between sig gen and
                                                          > xtal;
                                                          > > > and they are 90
                                                          > > > > degrees apart! Moreover the voltages are now
                                                          > 2.5
                                                          > > > volts on the
                                                          > > > > important pins of U8. So thank you Terry and
                                                          > Len
                                                          > > > for valuable
                                                          > > > > comments. Now to test with an antenna!
                                                          > > > >
                                                          > > > > 73
                                                          > > > > Geoff
                                                          > > > > G3XGC
                                                          > > > >
                                                          > > > > --- In softrock40@yahoogroups.com,
                                                          > > > "geoffrey_cottrell" <g3.xgc@>
                                                          > > > wrote:
                                                          > > > > >
                                                          > > > > > Len
                                                          > > > > >
                                                          > > > > > Thanks for that. I have compared the two
                                                          > > > circuits and noticed the
                                                          > > > > similarity - hence my
                                                          > > > > > earlier post. As there is no measured short
                                                          > on
                                                          > > > pins 7 and 8 of U8,
                                                          > > > > am beginning to
                                                          > > > > > suspect a fault in the chip itself.
                                                          > > > > >
                                                          > > > > > Geoff
                                                          > > > > >
                                                          > > > > > --- In softrock40@yahoogroups.com, Len
                                                          > Warner
                                                          > > > <novost@> wrote:
                                                          > > > > > >
                                                          > > > > > > At 08:41 07/04/18, Digest Number 1498
                                                          > wrote:
                                                          > > > > > > > Posted by: "geoffrey_cottrell"
                                                          > g3.xgc@
                                                          > > > geoffrey_cottrell
                                                          > > > > > > > Date: Wed Apr 18, 2007 12:31 am
                                                          > ((PDT))
                                                          > > > > > > >
                                                          > > > > > > >I should have mentioned that I have the
                                                          > RXTX
                                                          > > > 6.1 here.
                                                          > > > > > > >[snip]
                                                          > > > > > > >Do you know equivalent pin numbers for
                                                          > the
                                                          > > > RXTX?
                                                          > > > > > >
                                                          > > > > > > If you compare
                                                          > > > > > > "RXTXv6.1 schematic sheet 2 12_27.pdf"
                                                          > > > > > > and
                                                          > > > > > > "v6.2 SoftRock Lite schematic 12_18.pdf"
                                                          > > > > > > you will see that the circuits are very
                                                          > nearly
                                                          > > > identical,
                                                          > > > > > > with the exception of the antenna filter
                                                          > and
                                                          > > > JP1 and JP2.
                                                          > > > > > >
                                                          > > > > > > All the major components are in the same
                                                          > place
                                                          > > > in both
                                                          > > > > > > schematics, so it shouldn't be difficult
                                                          > to
                                                          > > > translate Terry's
                                                          > > > > > > SR6.2 test points into SR6.1 Rx ones. If
                                                          > you
                                                          > > > begin to
                                                          > > > > > > understand the circuit a little it should
                                                          > > > become obvious.
                                                          > > > > > >
                                                          >
                                                          === message truncated ===


                                                          =================
                                                          IN GOD WE TRUST !
                                                          =================
                                                          Russell Blair
                                                          QTH ========= Richardson Tx
                                                          CALL ========= NC5O
                                                          GRID ========= EM12px
                                                          FH# ========== 300
                                                          DOS# ========= 470
                                                          =================

                                                          __________________________________________________
                                                          Do You Yahoo!?
                                                          Tired of spam? Yahoo! Mail has the best spam protection around
                                                          http://mail.yahoo.com
                                                        Your message has been successfully submitted and would be delivered to recipients shortly.