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How sensitive (relatively) is the RXTX Ensemble receiver

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  • jvilardo2000
    I just completed enough of the RXTX Ensemble to turn it on and listen to the receiver. I dont know what to expect on performance from the softrock and not
    Message 1 of 10 , Jan 8, 2013
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      I just completed enough of the RXTX Ensemble to turn it on and listen to the receiver. I dont know what to expect on performance from the softrock and not sure I have everything set correctly. I am using a run of the mill sound card that is part of the motherboard of my win7 computer with I3 processor. The sample rate of the sound chip is 44100. I am using HDSDR software and have the the input /output band width set to 2400.

      I notice that signals dont visually appear much above the noise level on the spectra scope and I have to look hard to see a signal. Is this normal ? Would a better sound card like the DELTA 44 make a difference?

      I dont have tools to measure the absolute sensitivity but compared to my TS590 on the same antenna the softrock is much less sensitive than the TS590. Is this what I should expect from the softrock or do I have a failure somewhere in the softrock? The softrock has passed all of the tests so far, I don't have a signal generator so I could not perform the signal injection asked for.

      Any comments would be welcomed.

      Joe K3JV
    • Roger Critchlow
      What antenna? -- rec --
      Message 2 of 10 , Jan 8, 2013
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        What antenna?

        -- rec --


        On Tue, Jan 8, 2013 at 7:13 PM, jvilardo2000 <jvilardo@...> wrote:
         

        I just completed enough of the RXTX Ensemble to turn it on and listen to the receiver. I dont know what to expect on performance from the softrock and not sure I have everything set correctly. I am using a run of the mill sound card that is part of the motherboard of my win7 computer with I3 processor. The sample rate of the sound chip is 44100. I am using HDSDR software and have the the input /output band width set to 2400.

        I notice that signals dont visually appear much above the noise level on the spectra scope and I have to look hard to see a signal. Is this normal ? Would a better sound card like the DELTA 44 make a difference?

        I dont have tools to measure the absolute sensitivity but compared to my TS590 on the same antenna the softrock is much less sensitive than the TS590. Is this what I should expect from the softrock or do I have a failure somewhere in the softrock? The softrock has passed all of the tests so far, I don't have a signal generator so I could not perform the signal injection asked for.

        Any comments would be welcomed.

        Joe K3JV


      • Joe Vilardo
        The antenna is a 80/40 meter fan dipole at 50 feet. I have a switch that let s me switch between ts590 and the txrx ensemble. The relative sensitivity
        Message 3 of 10 , Jan 8, 2013
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          The antenna is a 80/40 meter fan dipole at 50 feet.  I have a switch that let's me switch between ts590 and the txrx ensemble. The relative sensitivity  between radios is significantly different on the same antenna.

          Joe Vilardo
          West Chester, PA



          On Jan 8, 2013, at 10:51 PM, Roger Critchlow <rec@...> wrote:

           

          What antenna?

          -- rec --


          On Tue, Jan 8, 2013 at 7:13 PM, jvilardo2000 <jvilardo@...> wrote:
           

          I just completed enough of the RXTX Ensemble to turn it on and listen to the receiver. I dont know what to expect on performance from the softrock and not sure I have everything set correctly. I am using a run of the mill sound card that is part of the motherboard of my win7 computer with I3 processor. The sample rate of the sound chip is 44100. I am using HDSDR software and have the the input /output band width set to 2400.

          I notice that signals dont visually appear much above the noise level on the spectra scope and I have to look hard to see a signal. Is this normal ? Would a better sound card like the DELTA 44 make a difference?

          I dont have tools to measure the absolute sensitivity but compared to my TS590 on the same antenna the softrock is much less sensitive than the TS590. Is this what I should expect from the softrock or do I have a failure somewhere in the softrock? The softrock has passed all of the tests so far, I don't have a signal generator so I could not perform the signal injection asked for.

          Any comments would be welcomed.

          Joe K3JV


        • Alan
          ... Subject: Re: [softrock40] How sensitive (relatively) is the RXTX Ensemble receiver ... Joe , The Softrock should hear as much, or more, than a 590 on those
          Message 4 of 10 , Jan 8, 2013
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            ----- Original Message -----
            Subject: Re: [softrock40] How sensitive (relatively) is the RXTX Ensemble receiver


            >The antenna is a 80/40 meter fan dipole at 50 feet. I have a switch that let's me switch between ts590 and the txrx ensemble. The
            >relative sensitivity between radios is significantly different on the same antenna.

            Joe ,

            The Softrock should hear as much, or more, than a 590 on those bands.

            > Would a better sound card like the DELTA 44 make a difference?

            Maybe, but it will only be a small difference. Probably not noticeable in most circumstances.

            You must have a problem, go back and check your soldering to the coils.
            Check the antenna switching.
            Check T5 is correctly wound.

            You can try removing the L4 connection, the other side from C39. Connect the antenna to the free end. This will bypass the antenna
            switching.

            73 Alan G4ZFQ
          • warrenallgyer
            Joe Alan forgot to give you the best advice he gives every newcomer: Watch the noise level on HDSDR as you connect and disconnect the antenna. It should rise
            Message 5 of 10 , Jan 9, 2013
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              Joe

              Alan forgot to give you the best advice he gives every newcomer: Watch the noise level on HDSDR as you connect and disconnect the antenna. It should rise significantly on 80 and 40 meters with the antenna connected.

              My guess is yours will not and that will be an indication of a problem in the signal path that Alan describes.

              Sorry Alan...... but it really is such good advice for a new guy and your reinforcing it with me at the outset has saved me several follicles over the two years of playing with these things.

              Warren Allgyer - W8TOD

              --- In softrock40@yahoogroups.com, "Alan" wrote:
              >
              >
              > ----- Original Message -----
              > Subject: Re: [softrock40] How sensitive (relatively) is the RXTX Ensemble receiver
              >
              >
              > >The antenna is a 80/40 meter fan dipole at 50 feet. I have a switch that let's me switch between ts590 and the txrx ensemble. The
              > >relative sensitivity between radios is significantly different on the same antenna.
              >
              > Joe ,
              >
              > The Softrock should hear as much, or more, than a 590 on those bands.
              >
              > > Would a better sound card like the DELTA 44 make a difference?
              >
              > Maybe, but it will only be a small difference. Probably not noticeable in most circumstances.
              >
              > You must have a problem, go back and check your soldering to the coils.
              > Check the antenna switching.
              > Check T5 is correctly wound.
              >
              > You can try removing the L4 connection, the other side from C39. Connect the antenna to the free end. This will bypass the antenna
              > switching.
              >
              > 73 Alan G4ZFQ
              >
            • Chris Wilson
              ... I run a TS-590 and a RXTX Ensemble. On the same 160 meter long horizontal quad loop antenna and balanced line matching unit the TS-590 will resolve an
              Message 6 of 10 , Jan 9, 2013
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                >
                > I just completed enough of the RXTX Ensemble to turn it on and
                > listen to the receiver. I dont know what to expect on performance
                > from the softrock and not sure I have everything set correctly. I am
                > using a run of the mill sound card that is part of the motherboard
                > of my win7 computer with I3 processor. The sample rate of the sound
                > chip is 44100. I am using HDSDR software and have the the input /output band width set to 2400.

                > I notice that signals dont visually appear much above the noise
                > level on the spectra scope and I have to look hard to see a signal.
                > Is this normal ? Would a better sound card like the DELTA 44 make a difference?

                > I dont have tools to measure the absolute sensitivity but compared
                > to my TS590 on the same antenna the softrock is much less sensitive
                > than the TS590. Is this what I should expect from the softrock or do
                > I have a failure somewhere in the softrock? The softrock has passed
                > all of the tests so far, I don't have a signal generator so I could
                > not perform the signal injection asked for.

                > Any comments would be welcomed.

                > Joe K3JV

                I run a TS-590 and a RXTX Ensemble. On the same 160 meter long
                horizontal quad loop antenna and balanced line matching unit the TS-590
                will resolve an incredibly weak SSB signal a tiny bit better than the
                Softrock, as is to be hoped, given the price difference! It *IS*
                marginal though. Factor in that the RX audio on the Softrock is
                infinitely better than the TS-590, as is the ease of operation via
                HPSDR, and it's obvious why 95% of my listening is done with the
                Softrock, with the 590 tracking it via Omni Rig software, ready to TX
                if I need a good few Watts. The 590 TX audio is bad, too. I am one of
                the few who own a 590 that's not too proud to admit it. I can
                recognize another 590 just by listening on the Softrock, they have a
                certain "digital" sound with a sort of scratchiness in the mid to high
                end of the audio range. Plus they have measly RX and TX audio
                bandwidth should you want to listen to a wide band SSB transmission,
                or take part in one, but that's an aside.

                Now, if I run this RXTX on my Asus motherboard's on board sound card
                the noise floor rises to double what I see now, and the ability to
                resolve all but strong signals is gone immediately. As soon as I
                bought an M-Audio Delta 44 card the change was night and day and I
                suddenly realised where these SDR folks were coming from. Others seem
                happy with their on board card or cheaper stand alone one. Maybe my on
                board sound "card" is faulty?

                As another aside my gripe with the SDR I have used is the difficulty
                interfacing SDR stuff to other gear and applications. Mainly due to
                the constraints of multiple devices communicating over effectively a
                single USB port. I want to move up to a DDC / DUC SDR next, but will
                only do so if I can wave good bye to USB stuff and know inter
                operability of logging software, and flawless remote operation from a
                PC in a different part of my hose is possible. I am investigating this
                currently. The devil is in the software, IMO.

                09/01/2013 11:40



                --
                Best Regards,
                Chris Wilson. 2E0ILY
              • Alan
                ... Subject: Re: [softrock40] How sensitive (relatively) is the RXTX Ensemble receiver ... Chris, This is certainly not typical of modern on-board cards.
                Message 7 of 10 , Jan 9, 2013
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                  ----- Original Message -----
                  Subject: Re: [softrock40] How sensitive (relatively) is the RXTX Ensemble receiver


                  >
                  > Now, if I run this RXTX on my Asus motherboard's on board sound card
                  > the noise floor rises to double what I see now, and the ability to
                  > resolve all but strong signals is gone immediately. As soon as I
                  > bought an M-Audio Delta 44 card the change was night and day and I
                  > suddenly realised where these SDR folks were coming from. Others seem
                  > happy with their on board card or cheaper stand alone one. Maybe my on
                  > board sound "card" is faulty?
                  >

                  Chris,

                  This is certainly not typical of modern on-board cards.
                  Several I've seen are better than some of the PCI cards used a few years ago. Even those were usually adequate to get a Softrock
                  going well. Even a really bad card will receive medium/strong signals.
                  Incorrect settings can make them look bad but that is usually obvious when someone describes what they see.
                  The problem with modern sound systems is their software. So many mixer/enhancement settings and no option to install just the basic
                  driver.

                  Joe,

                  As Warren says, on 80m you should see a big increase in noise when the antenna is connected. But if you see this then the Softrock
                  should be receiveing satisfactorily.
                  With no antenna connected you may well see a slight noise decrease when the Softrock power is removed. That's a test that shows the
                  card is as sensitive as it needs to be on the quietest bands.

                  73 Alan G4ZFQ
                • warrenallgyer
                  Chris To reinforce what Alan says a bit... I use the cheapest Netbook I can find, the current one is an MSI EePC I bought in Taiwan for less than $130 USD, and
                  Message 8 of 10 , Jan 9, 2013
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                    Chris

                    To reinforce what Alan says a bit... I use the cheapest Netbook I can find, the current one is an MSI EePC I bought in Taiwan for less than $130 USD, and I use the internal sound cards. I have made extensive measurements an I can tell you with some certainty that you will hear any signal that can be resolved by the Softrocks just as well on this audio card as you will on the M44 or any "professional" audio card.

                    There are advantages to the high priced cards: 192 KHz sampling, greater dynamic range, and.... well there MUST be others. But the incongruity of using a thousand dollar PC with a 500 dollar audio card to listen to an $89 transceiver leaves me scratching my head.

                    With a normally operating internal card your antenna noise on any band below 30 MHz is going to be a minimum of 15 dB above the noise floor of that card. Spending $500 do lower the noise a few dB further makes no sense to me....you will never be able to hear or measure any improvement.

                    As I have said before.... spend your money on antennas, whiskey, and flowers for your wife. All will give you a much better return than a high priced audio card.

                    ....... IMHO of course.

                    Warren Allgyer - W8TOD

                    --- In softrock40@yahoogroups.com, "Alan" wrote:
                    >
                    >
                    > ----- Original Message -----
                    > Subject: Re: [softrock40] How sensitive (relatively) is the RXTX Ensemble receiver
                    >
                    >
                    > >
                    > > Now, if I run this RXTX on my Asus motherboard's on board sound card
                    > > the noise floor rises to double what I see now, and the ability to
                    > > resolve all but strong signals is gone immediately. As soon as I
                    > > bought an M-Audio Delta 44 card the change was night and day and I
                    > > suddenly realised where these SDR folks were coming from. Others seem
                    > > happy with their on board card or cheaper stand alone one. Maybe my on
                    > > board sound "card" is faulty?
                    > >
                    >
                    > Chris,
                    >
                    > This is certainly not typical of modern on-board cards.
                    > Several I've seen are better than some of the PCI cards used a few years ago. Even those were usually adequate to get a Softrock
                    > going well. Even a really bad card will receive medium/strong signals.
                    > Incorrect settings can make them look bad but that is usually obvious when someone describes what they see.
                    > The problem with modern sound systems is their software. So many mixer/enhancement settings and no option to install just the basic
                    > driver.
                    >
                    > Joe,
                    >
                    > As Warren says, on 80m you should see a big increase in noise when the antenna is connected. But if you see this then the Softrock
                    > should be receiveing satisfactorily.
                    > With no antenna connected you may well see a slight noise decrease when the Softrock power is removed. That's a test that shows the
                    > card is as sensitive as it needs to be on the quietest bands.
                    >
                    > 73 Alan G4ZFQ
                    >
                  • Chris Wilson
                    ... 09/01/2013 16:16 There may well be something wrong with the on board sound, I have no way of telling, plus the mother board is at least 8 years old (I am
                    Message 9 of 10 , Jan 9, 2013
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                      >
                      > Chris

                      > To reinforce what Alan says a bit... I use the cheapest Netbook I
                      > can find, the current one is an MSI EePC I bought in Taiwan for less
                      > than $130 USD, and I use the internal sound cards. I have made
                      > extensive measurements an I can tell you with some certainty that
                      > you will hear any signal that can be resolved by the Softrocks just
                      > as well on this audio card as you will on the M44 or any "professional" audio card.

                      > There are advantages to the high priced cards: 192 KHz sampling,
                      > greater dynamic range, and.... well there MUST be others. But the
                      > incongruity of using a thousand dollar PC with a 500 dollar audio
                      > card to listen to an $89 transceiver leaves me scratching my head.

                      > With a normally operating internal card your antenna noise on any
                      > band below 30 MHz is going to be a minimum of 15 dB above the noise
                      > floor of that card. Spending $500 do lower the noise a few dB
                      > further makes no sense to me....you will never be able to hear or measure any improvement.

                      > As I have said before.... spend your money on antennas, whiskey,
                      > and flowers for your wife. All will give you a much better return than a high priced audio card.

                      > ....... IMHO of course.

                      > Warren Allgyer - W8TOD

                      09/01/2013 16:16

                      There may well be something wrong with the on board sound, I have no
                      way of telling, plus the mother board is at least 8 years old (I am
                      not one to change PC's like socks :)) Hopefully my next big spend will
                      be away from sound card based SDR, as the fantastic fun I have had
                      with the Softrocks has made me believe that a conventional transceiver
                      with or without kludged on panadaptors is history for me, but SDR is now in my
                      blood, and a fully encapsulated DDC SDR is going to be my next
                      purchase. I still have a couple of SR kits to build, and I can never see
                      me selling the Softrocks, they are quite dear to me! Flowers for the
                      wife? Has that sawn through brake pipe failed at last.... ;)




                      --
                      Best Regards,
                      Chris Wilson. 2E0ILY
                    • Joe Vilardo
                      Alan Finally sorted out the issue with low sensitivity. I had several false starts; rewound T5 , thought I might have reversed the bifilar winding direction
                      Message 10 of 10 , Jan 13, 2013
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                        Alan
                         
                        Finally sorted out the issue with low sensitivity.  I had several false starts; rewound T5 , thought I might have reversed the bifilar winding direction and concerned that I was too aggressive with the number of twists per inch, but that wasn’t the problem. I rechecked DC voltages several times but no joy. I never could see any change in the noise floor when I attached the antenna and decided to try your suggestion of by passing the rf switching and attach the antenna direct to L4. Not easy to unsolder the #30 wire lead from it’s pad but it was worth the effort because the receiver came to life.  The Softrock has a very nice receiver NOW.  I re-attached the end of L4 and took a close look at Q10’s solder pads with the 10X eye loupe and thought that there could be a solder bridge between two of the pads so I solder wicked the pads to be on the safe side.  I rechecked all the voltages in the rx switching path from the supplemental notes
                        of G8VOI and they were in the ball park.  My conclusion is that in my original install of L4 I didn’t get all the enamel off at the point of attachment OR a solder bridge at Q10.
                         
                        This receiver sensitivity is equal or better than the TS590 and that is great !
                         
                        Thanks for the supporting comments and the suggestions.  It is nice to know I am not out here alone trying to get through this challenging project.
                         
                        Joe K3JV
                         
                        From: Alan
                        Sent: Wednesday, January 09, 2013 2:39 AM
                        Subject: Re: [softrock40] How sensitive (relatively) is the RXTX Ensemble receiver
                         
                         


                        ----- Original Message -----
                        Subject: Re: [softrock40] How sensitive (relatively) is the RXTX Ensemble receiver

                        >The antenna is a 80/40 meter fan dipole at 50 feet. I have a switch that let's me switch between ts590 and the txrx ensemble. The
                        >relative sensitivity between radios is significantly different on the same antenna.

                        Joe ,

                        The Softrock should hear as much, or more, than a 590 on those bands.

                        > Would a better sound card like the DELTA 44 make a difference?

                        Maybe, but it will only be a small difference. Probably not noticeable in most circumstances.

                        You must have a problem, go back and check your soldering to the coils.
                        Check the antenna switching.
                        Check T5 is correctly wound.

                        You can try removing the L4 connection, the other side from C39. Connect the antenna to the free end. This will bypass the antenna
                        switching.

                        73 Alan G4ZFQ

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