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Re: Ensemble RXTX for 40/30/20 debate

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  • warrenallgyer
    The first clue I had on the varying impedance issue was when I built the external filter breadboard to test the new values in the first place. I terminated on
    Message 1 of 25 , Jan 5, 2013
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      The first clue I had on the varying impedance issue was when I built the external filter breadboard to test the new values in the first place. I terminated on side of the test filter and then fed the MFJ directly into the other side, measuring the voltage across the termination on the scope. It was a sort of manual sweep generator and I could very quickly see when the output level started to drop off as I swept up through 11 MHz or so. In the process I noted that the VSWR indication on the old MFJ was very low, nearly 1:1 at 7 MHz and it started to rise rapidly in correspondence with the output level falling off at higher frequencies.

      Similarly I have noted in the past when tuning up my antenna tuner, using a scope on the input to the tuner as a power indicator, that the indicated voltage at the scope rises rapidly as the tuner VSWR goes up.

      I like Orin's characterization of "attenuation" in these filters. The power in those harmonics and the portion of the fundamental that gets "scraped off" by the filter is substantial and it is not heating the filter. It is being reflected back and dissipated in the finals and one indication of this appears to be a rise in the measured voltage at the filter input.

      I really do apologize for the tedium this subject has brought to some. Allen has it exactly right from my point of view in that this is a learning opportunity and my excitement at that gets a little overactive at times. I have learned a ton from what you guys have written in these exchanges and I hope those I have bored to tears can just make allowances and skip over the topic.

      Thanks again for a great discussion!

      Warren Allgyer - W8TOD

      --- In softrock40@yahoogroups.com, "Orin" wrote:
      >
      >
      > --- In softrock40@yahoogroups.com, "allenbh57" wrote:
      > >
      > > Hi Tony, Warren and Alan,
      > >
      > > Very interesting discussion on the filters for 20-30-40. Warren, I
      > liked your thought that the Z of the filter may not be the same in your
      > test setup and the board, therefore the differences. Just for fun and
      > related information (isn't information being fun one reason we do this?
      > Hi Hi), would a VNA (don't have one available) or other suitable piece
      > of equipment measure the impedance of the filters as a black-box?
      >
      >
      > Yes, a VNA works fine for measuring the Z of the filter. You get
      > something like this:
      >
      > VNWA scan of 15/12/10m filter
      >
      JzHAUEj7Cg?feat=directlink>
      >
      > though that's for the 15-12-10m build and I didn't have the actual
      > impedance displayed. An antenna analyzer such as the MFJ 259B works
      > too if you terminate the filter output in 50 ohms; it will display
      > impedance, though the 259B doesn't give the sign of the reactive
      > component.
      >
      >
      > > For that matter, thinking off the top, could a directional coupler
      > between the amp and the BPF be used to show what is happening here?
      > Except that wold probably introduce another impedance into the mix.
      > >
      >
      > About to wander slightly off topic here on what they don't tell you
      > about filters; at least what they didn't tell me!
      >
      > That could work depending on what you have to look at the output from
      > the coupler. What you should see with these filters is no (ideally)
      > reverse power in the passband and for it to increase rapidly after the
      > cutoff frequency. Yes, I don't think the amateur radio exams I've taken
      > mention it, but this kind of filter doesn't do anything with input at
      > frequencies higher than the cutoff frequency, they merely bounce it back
      > to the source.
      >
      > Even though I might have said filter attenuation in the past, using the
      > term 'attenuate' can be misleading. Unlike an attenuator where power
      > that isn't passed through is turned into heat, these filters bounce the
      > harmonics back to the PA! (Rather unfortunate when you select the wrong
      > band/low pass filter on you amplifier. Say you leave you 40m LPF in and
      > transmit on 20m, almost all your power bounces back. Hopefully the PA
      > survives this abuse!) In the passband, there will be some slight
      > attenuation due to losses in the coils and capacitors, but it's usually
      > only a few tenths of a dB, depending on the Q of the coils and
      > capacitors.
      >
      > Orin.
      >
    • Anthony Casorso
      The AADE filter designer program that I use allows you to plot the filter input and output impedance vs frequency. I suspect that ELSIE does too. If you take a
      Message 2 of 25 , Jan 5, 2013
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        The AADE filter designer program that I use allows you to plot the filter input and output impedance vs frequency. I suspect that ELSIE does too. If you take a typical filter design, say a Chebyshev 5th order bandpass, and look at the impedance variation with frequency you will see that it is quite variable. A 50 ohm filter is almost never exactly 50 ohms and you can expect excursions from 10 to 150 ohms, depending on the filter specifics. This is just the nature of the beast. 

        Tony





      • Dave Miller
        Awesome discussion. As a newbie I am entitled to a couple dumb questions. ;-) I have a Peaberry 40,30,20. I have been struggling with testing out the TX. From
        Message 3 of 25 , Jan 9, 2013
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          Awesome discussion.
          As a newbie I am entitled to a couple dumb questions. ;-)
          I have a Peaberry 40,30,20.
          I have been struggling with testing out the TX. From what I have seen the filters do deserve a good look. In my testing 2nd and 3rd harmonics on 40 m were hardly attenuated. Building and testing filter filter got waylaid by getting software working on TX. :-(
          My biggest problem is getting the thing to transmit ia fashion suitable for testing.
          I was using HDSDR but have concluded its not really ready for transmit. I was trying to test on CW. Finally resorted to SSB and the whistle test. If I could only whistle.

          Briefly tried Rocky but seemed not to have much joy.

          I finally got PowerSDR-IQ running on RX. Have not got to TX yet but have not tried.

          So the question is. Can someone outline in some detail what software and method used to test TX on Ensemble RXTX (will work fine on Peaberry :-) ) ?
          I have the gear (dummy load, sampling Tap and Spec Analyzer) and knowledge to capture the data just too dumb to coax a continuous carrier out of the beast to capture.

          I have all the parts for the External Filter and will build it soon. I will sweep it when complete. I will post results. I got a VNWA3 for Christmas so I can post pretty pictures. ;-).

          Last question. Yes I know I may be exceeding number of allowable questions for the day. ;-)
          How much computing horsepower is required to run PowerSDR? I am using the version from the links on SdRBuzz? For testing on the bench I would like to use my old EEPC netbook. Will it work? HDSDR seemed to work on it. Ate they similar in computing requirements.

          Thanks all. Just amazed at the on air performance of the receiver. Like other have said after SDR it's hard to go back to no panadpter.
          Dave
          VE7PKE



          --- In softrock40@yahoogroups.com, "warrenallgyer" wrote:
          >
          > The first clue I had on the varying impedance issue was when I built the external filter breadboard to test the new values in the first place. I terminated on side of the test filter and then fed the MFJ directly into the other side, measuring the voltage across the termination on the scope. It was a sort of manual sweep generator and I could very quickly see when the output level started to drop off as I swept up through 11 MHz or so. In the process I noted that the VSWR indication on the old MFJ was very low, nearly 1:1 at 7 MHz and it started to rise rapidly in correspondence with the output level falling off at higher frequencies.
          >
          > Similarly I have noted in the past when tuning up my antenna tuner, using a scope on the input to the tuner as a power indicator, that the indicated voltage at the scope rises rapidly as the tuner VSWR goes up.
          >
          > I like Orin's characterization of "attenuation" in these filters. The power in those harmonics and the portion of the fundamental that gets "scraped off" by the filter is substantial and it is not heating the filter. It is being reflected back and dissipated in the finals and one indication of this appears to be a rise in the measured voltage at the filter input.
          >
          > I really do apologize for the tedium this subject has brought to some. Allen has it exactly right from my point of view in that this is a learning opportunity and my excitement at that gets a little overactive at times. I have learned a ton from what you guys have written in these exchanges and I hope those I have bored to tears can just make allowances and skip over the topic.
          >
          > Thanks again for a great discussion!
          >
          > Warren Allgyer - W8TOD
          >
          > --- In softrock40@yahoogroups.com, "Orin" wrote:
          > >
          > >
          > > --- In softrock40@yahoogroups.com, "allenbh57" wrote:
          > > >
          > > > Hi Tony, Warren and Alan,
          > > >
          > > > Very interesting discussion on the filters for 20-30-40. Warren, I
          > > liked your thought that the Z of the filter may not be the same in your
          > > test setup and the board, therefore the differences. Just for fun and
          > > related information (isn't information being fun one reason we do this?
          > > Hi Hi), would a VNA (don't have one available) or other suitable piece
          > > of equipment measure the impedance of the filters as a black-box?
          > >
          > >
          > > Yes, a VNA works fine for measuring the Z of the filter. You get
          > > something like this:
          > >
          > > VNWA scan of 15/12/10m filter
          > >
          > JzHAUEj7Cg?feat=directlink>
          > >
          > > though that's for the 15-12-10m build and I didn't have the actual
          > > impedance displayed. An antenna analyzer such as the MFJ 259B works
          > > too if you terminate the filter output in 50 ohms; it will display
          > > impedance, though the 259B doesn't give the sign of the reactive
          > > component.
          > >
          > >
          > > > For that matter, thinking off the top, could a directional coupler
          > > between the amp and the BPF be used to show what is happening here?
          > > Except that wold probably introduce another impedance into the mix.
          > > >
          > >
          > > About to wander slightly off topic here on what they don't tell you
          > > about filters; at least what they didn't tell me!
          > >
          > > That could work depending on what you have to look at the output from
          > > the coupler. What you should see with these filters is no (ideally)
          > > reverse power in the passband and for it to increase rapidly after the
          > > cutoff frequency. Yes, I don't think the amateur radio exams I've taken
          > > mention it, but this kind of filter doesn't do anything with input at
          > > frequencies higher than the cutoff frequency, they merely bounce it back
          > > to the source.
          > >
          > > Even though I might have said filter attenuation in the past, using the
          > > term 'attenuate' can be misleading. Unlike an attenuator where power
          > > that isn't passed through is turned into heat, these filters bounce the
          > > harmonics back to the PA! (Rather unfortunate when you select the wrong
          > > band/low pass filter on you amplifier. Say you leave you 40m LPF in and
          > > transmit on 20m, almost all your power bounces back. Hopefully the PA
          > > survives this abuse!) In the passband, there will be some slight
          > > attenuation due to losses in the coils and capacitors, but it's usually
          > > only a few tenths of a dB, depending on the Q of the coils and
          > > capacitors.
          > >
          > > Orin.
          > >
          >
        • Alan
          ... Subject: [softrock40] Re: Ensemble RXTX for 40/30/20 debate ... Assuming the Peaberry is like the Softrock it will need an extra LPF, Oh I see you just
          Message 4 of 25 , Jan 9, 2013
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            ----- Original Message -----
            Subject: [softrock40] Re: Ensemble RXTX for 40/30/20 debate


            > I have a Peaberry 40,30,20.
            > I have been struggling with testing out the TX. From what I have seen the filters do deserve a good look. In my testing 2nd and
            > 3rd harmonics on 40 m were hardly attenuated.

            Assuming the Peaberry is like the Softrock it will need an extra LPF, Oh I see you just have not built it.
            What values did you use in the integral LPF?

            Building and testing filter filter got waylaid by getting software working on TX. :-(
            > My biggest problem is getting the thing to transmit ia fashion suitable for testing.
            > I was using HDSDR but have concluded its not really ready for transmit. I was trying to test on CW.

            You will get a constant carrier on AM or FM.

            >I got a VNWA3 for Christmas so I can post pretty pictures. ;-).

            Make sure we can understand what they tell us:) Gerhard posted some and I'm puzzled!

            >
            > Last question. Yes I know I may be exceeding number of allowable questions for the day. ;-)
            > How much computing horsepower is required to run PowerSDR? I am using the version from the links on SdRBuzz? For testing on the
            > bench I would like to use my old EEPC netbook. Will it work? HDSDR seemed to work on it. Ate they similar in computing
            > requirements.

            Probably much the same. Just look at the CPU usage, if it goes over 50% it could be borderline.
            Probably the latest PDSR-IQ is the best bet if you go that way.

            73 Alan G4ZFQ
          • Dave Miller
            Alan, thanks for reply. See below. First off I see that as I failed to refresh my cache a significant amount of discussion has occurred on the topic of what
            Message 5 of 25 , Jan 9, 2013
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              Alan, thanks for reply. See below.
              First off I see that as I failed to refresh my cache a significant amount of discussion has occurred on the topic of what component vales to use for LPF. I was going to use what are in Dave T's build instructions. I printed them off last week. Given all the debate where is the most up to date and definitive turn and cap values?



              --- In softrock40@yahoogroups.com, "Alan" wrote:
              >
              >
              > ----- Original Message -----
              > Subject: [softrock40] Re: Ensemble RXTX for 40/30/20 debate
              >
              >
              > > I have a Peaberry 40,30,20.
              > > I have been struggling with testing out the TX. From what I have seen the filters do deserve a good look. In my testing 2nd and
              > > 3rd harmonics on 40 m were hardly attenuated.
              >
              > Assuming the Peaberry is like the Softrock it will need an extra LPF, Oh I see you just have not built it.
              > What values did you use in the integral LPF?

              Whatever were in the AE9RB online directions? What should I use?
              >
              > Building and testing filter filter got waylaid by getting software working on TX. :-(
              > > My biggest problem is getting the thing to transmit ia fashion suitable for testing.
              > > I was using HDSDR but have concluded its not really ready for transmit. I was trying to test on CW.
              >
              > You will get a constant carrier on AM or FM.
              I shall try that. Still want to get CW working. Have been talking to LC via email and understand HDSDR state on this.
              >
              > >I got a VNWA3 for Christmas so I can post pretty pictures. ;-).
              >
              > Make sure we can understand what they tell us:) Gerhard posted some and I'm puzzled!
              I shall. You can display so many traces . ;-) Its very confusing at first. starting to getba handle on it. I will try to post a couple of versions. The easy to understand and the full meal deal. For this just a simple thru measurement showing attenuation verses frequency is what counts and is easy to do on an external LPF. Orrin points out doing it properly on an internal gets more difficult.
              >
              > >
              > > Last question. Yes I know I may be exceeding number of allowable questions for the day. ;-)
              > > How much computing horsepower is required to run PowerSDR? I am using the version from the links on SdRBuzz? For testing on the
              > > bench I would like to use my old EEPC netbook. Will it work? HDSDR seemed to work on it. Ate they similar in computing
              > > requirements.
              >
              > Probably much the same. Just look at the CPU usage, if it goes over 50% it could be borderline.
              > Probably the latest PDSR-IQ is the best bet if you go that way.
              Ok Alan, thanks. Lots to learn. I appreciate all the assistance the group provides.
              I will have to keep up to date here.

              Thanks
              Dave
              VE7PKE

              >
              > 73 Alan G4ZFQ
              >
            • Dave Miller
              Alan, Just has a look at the wonderful pictures. The crib notes are just look at the S21 traces. S21 is the amount of the signal passing thru the filter. So
              Message 6 of 25 , Jan 9, 2013
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                Alan,
                Just has a look at the wonderful pictures.
                The crib notes are just look at the S21 traces.
                S21 is the amount of the signal passing thru the filter. So the hump should be where we want the signal to pass.
                The memory traces are other captures. Not clear on what they are.
                S11 is the reflection as measured from the input.

                I hope this helps.

                Many thanks for the OP for posting those pictures.

                Thanks
                Dave
                VE7PKE

                The memory traces are previous traces and without a detailed explanation rather difficult to follow

                --- In softrock40@yahoogroups.com, "Alan" wrote:
                >
                >
                > ----- Original Message -----
                > Subject: [softrock40] Re: Ensemble RXTX for 40/30/20 debate
                >
                >
                > > I have a Peaberry 40,30,20.
                > > I have been struggling with testing out the TX. From what I have seen the filters do deserve a good look. In my testing 2nd and
                > > 3rd harmonics on 40 m were hardly attenuated.
                >
                > Assuming the Peaberry is like the Softrock it will need an extra LPF, Oh I see you just have not built it.
                > What values did you use in the integral LPF?
                >
                > Building and testing filter filter got waylaid by getting software working on TX. :-(
                > > My biggest problem is getting the thing to transmit ia fashion suitable for testing.
                > > I was using HDSDR but have concluded its not really ready for transmit. I was trying to test on CW.
                >
                > You will get a constant carrier on AM or FM.
                >
                > >I got a VNWA3 for Christmas so I can post pretty pictures. ;-).
                >
                > Make sure we can understand what they tell us:) Gerhard posted some and I'm puzzled!
                >
                > >
                > > Last question. Yes I know I may be exceeding number of allowable questions for the day. ;-)
                > > How much computing horsepower is required to run PowerSDR? I am using the version from the links on SdRBuzz? For testing on the
                > > bench I would like to use my old EEPC netbook. Will it work? HDSDR seemed to work on it. Ate they similar in computing
                > > requirements.
                >
                > Probably much the same. Just look at the CPU usage, if it goes over 50% it could be borderline.
                > Probably the latest PDSR-IQ is the best bet if you go that way.
                >
                > 73 Alan G4ZFQ
                >
              • Alan
                ... Subject: [softrock40] Re: Ensemble RXTX for 40/30/20 debate ... Tony has altered the design slightly. It was found the HF cutoff was too low. See Robby s
                Message 7 of 25 , Jan 9, 2013
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                  ----- Original Message -----
                  Subject: [softrock40] Re: Ensemble RXTX for 40/30/20 debate


                  > Given all the debate where is the most up to date and definitive turn and cap values?
                  >

                  Tony has altered the design slightly. It was found the HF cutoff was too low. See Robby's pages
                  http://www.wb5rvz.org/ensemble_rxtx/ and set the band option. The revision is on RF/IO.

                  If already built I reckon two turns maximum removed from L2 and L3 should make the LPF conform to the original design if problems
                  are seen with the 20m output.

                  73 Alan G4ZFQ
                • John Greusel
                  Two turn is exactly what I did and then I measured the inductance and it was spot on to the original specs. Whistling yields almost 2.5 watts on 20 meters so
                  Message 8 of 25 , Jan 9, 2013
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                    Two turn is exactly what I did and then I measured the inductance and it was spot on to the original specs.
                    Whistling yields almost 2.5 watts on 20 meters so I've had to throttle back the output now.

                    John
                    KC9OJV
                     



                    From: Alan <alan4alan@...>
                    To: softrock40@yahoogroups.com
                    Sent: Wednesday, January 9, 2013 10:13 AM
                    Subject: Re: [softrock40] Re: Ensemble RXTX for 40/30/20 debate

                     

                    ----- Original Message -----
                    Subject: [softrock40] Re: Ensemble RXTX for 40/30/20 debate

                    > Given all the debate where is the most up to date and definitive turn and cap values?
                    >

                    Tony has altered the design slightly. It was found the HF cutoff was too low. See Robby's pages
                    http://www.wb5rvz.org/ensemble_rxtx/ and set the band option. The revision is on RF/IO.

                    If already built I reckon two turns maximum removed from L2 and L3 should make the LPF conform to the original design if problems
                    are seen with the 20m output.

                    73 Alan G4ZFQ



                  • Orin
                    If you are talking about my VNWA scan that I posted a few days back in this thread, the memory traces are the theoretical filter responses as calculated by
                    Message 9 of 25 , Jan 9, 2013
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                      If you are talking about my VNWA scan that I posted a few days back in this thread, the memory traces are the theoretical filter responses as calculated by "Elsie".

                      Orin.

                      --- In softrock40@yahoogroups.com, "Dave Miller" wrote:
                      >
                      > Alan,
                      > Just has a look at the wonderful pictures.
                      > The crib notes are just look at the S21 traces.
                      > S21 is the amount of the signal passing thru the filter. So the hump should be where we want the signal to pass.
                      > The memory traces are other captures. Not clear on what they are.
                      > S11 is the reflection as measured from the input.
                      >
                      > I hope this helps.
                      >
                      > Many thanks for the OP for posting those pictures.
                      >
                      > Thanks
                      > Dave
                      > VE7PKE
                      >
                      > The memory traces are previous traces and without a detailed explanation rather difficult to follow
                      >
                      > --- In softrock40@yahoogroups.com, "Alan" wrote:
                      > >
                      > >
                      > > ----- Original Message -----
                      > > Subject: [softrock40] Re: Ensemble RXTX for 40/30/20 debate
                      > >
                      > >
                      > > > I have a Peaberry 40,30,20.
                      > > > I have been struggling with testing out the TX. From what I have seen the filters do deserve a good look. In my testing 2nd and
                      > > > 3rd harmonics on 40 m were hardly attenuated.
                      > >
                      > > Assuming the Peaberry is like the Softrock it will need an extra LPF, Oh I see you just have not built it.
                      > > What values did you use in the integral LPF?
                      > >
                      > > Building and testing filter filter got waylaid by getting software working on TX. :-(
                      > > > My biggest problem is getting the thing to transmit ia fashion suitable for testing.
                      > > > I was using HDSDR but have concluded its not really ready for transmit. I was trying to test on CW.
                      > >
                      > > You will get a constant carrier on AM or FM.
                      > >
                      > > >I got a VNWA3 for Christmas so I can post pretty pictures. ;-).
                      > >
                      > > Make sure we can understand what they tell us:) Gerhard posted some and I'm puzzled!
                      > >
                      > > >
                      > > > Last question. Yes I know I may be exceeding number of allowable questions for the day. ;-)
                      > > > How much computing horsepower is required to run PowerSDR? I am using the version from the links on SdRBuzz? For testing on the
                      > > > bench I would like to use my old EEPC netbook. Will it work? HDSDR seemed to work on it. Ate they similar in computing
                      > > > requirements.
                      > >
                      > > Probably much the same. Just look at the CPU usage, if it goes over 50% it could be borderline.
                      > > Probably the latest PDSR-IQ is the best bet if you go that way.
                      > >
                      > > 73 Alan G4ZFQ
                      > >
                      >
                    • Dave Miller
                      Orin, I was actually referring to Gerhards new pictures. I got around to measuring the inductors for my external 40 m low pass on my 40,30,20 unit. Once I
                      Message 10 of 25 , Jan 9, 2013
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                        Orin,
                        I was actually referring to Gerhards new pictures.
                        I got around to measuring the inductors for my external 40 m low pass on my 40,30,20 unit. Once I removed the magic 2 turns they are now 1.3uH @10MHz according to my VNWA. Caps measured as marked so I figure I had things calibrated properly.

                        Slowly figuring this all out. I will have to pull the two inductors in on board Bandpass and measure them.

                        Thanks
                        Dave

                        --- In softrock40@yahoogroups.com, "Orin" wrote:
                        >
                        > If you are talking about my VNWA scan that I posted a few days back in this thread, the memory traces are the theoretical filter responses as calculated by "Elsie".
                        >
                        > Orin.
                        >
                        > --- In softrock40@yahoogroups.com, "Dave Miller" wrote:
                        > >
                        > > Alan,
                        > > Just has a look at the wonderful pictures.
                        > > The crib notes are just look at the S21 traces.
                        > > S21 is the amount of the signal passing thru the filter. So the hump should be where we want the signal to pass.
                        > > The memory traces are other captures. Not clear on what they are.
                        > > S11 is the reflection as measured from the input.
                        > >
                        > > I hope this helps.
                        > >
                        > > Many thanks for the OP for posting those pictures.
                        > >
                        > > Thanks
                        > > Dave
                        > > VE7PKE
                        > >
                        > > The memory traces are previous traces and without a detailed explanation rather difficult to follow
                        > >
                        > > --- In softrock40@yahoogroups.com, "Alan" wrote:
                        > > >
                        > > >
                        > > > ----- Original Message -----
                        > > > Subject: [softrock40] Re: Ensemble RXTX for 40/30/20 debate
                        > > >
                        > > >
                        > > > > I have a Peaberry 40,30,20.
                        > > > > I have been struggling with testing out the TX. From what I have seen the filters do deserve a good look. In my testing 2nd and
                        > > > > 3rd harmonics on 40 m were hardly attenuated.
                        > > >
                        > > > Assuming the Peaberry is like the Softrock it will need an extra LPF, Oh I see you just have not built it.
                        > > > What values did you use in the integral LPF?
                        > > >
                        > > > Building and testing filter filter got waylaid by getting software working on TX. :-(
                        > > > > My biggest problem is getting the thing to transmit ia fashion suitable for testing.
                        > > > > I was using HDSDR but have concluded its not really ready for transmit. I was trying to test on CW.
                        > > >
                        > > > You will get a constant carrier on AM or FM.
                        > > >
                        > > > >I got a VNWA3 for Christmas so I can post pretty pictures. ;-).
                        > > >
                        > > > Make sure we can understand what they tell us:) Gerhard posted some and I'm puzzled!
                        > > >
                        > > > >
                        > > > > Last question. Yes I know I may be exceeding number of allowable questions for the day. ;-)
                        > > > > How much computing horsepower is required to run PowerSDR? I am using the version from the links on SdRBuzz? For testing on the
                        > > > > bench I would like to use my old EEPC netbook. Will it work? HDSDR seemed to work on it. Ate they similar in computing
                        > > > > requirements.
                        > > >
                        > > > Probably much the same. Just look at the CPU usage, if it goes over 50% it could be borderline.
                        > > > Probably the latest PDSR-IQ is the best bet if you go that way.
                        > > >
                        > > > 73 Alan G4ZFQ
                        > > >
                        > >
                        >
                      • joelweder
                        I used to practice trying to whistle different tones when I worked repairing Motorola rigs years ago. But if you can t whistle, PowerSDR has a nice tone
                        Message 11 of 25 , Mar 3, 2013
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                          I used to practice trying to whistle different tones when I worked repairing Motorola rigs years ago. But if you can't whistle, PowerSDR has a nice tone generator built right in!

                          There may be some easier way to do this, but I used the Two Tone test feature in Setup. I'm using PowerSDR-IQ 2.4.4. Click on Setup, then go to the Tests tab. By default the tones are set to 700 and 1900 Hz. I set them both to the same value eg 1000 Hz.

                          The MOX button will put the radio into transmit but minimal power is transmitted when you're on a Sideband mode, so that doesn't work unless you can figure out a way to whistle into your mic! (or get an audio tone generator)

                          Joel VE6EI

                          --- In softrock40@yahoogroups.com, "Dave Miller" <ve7pke@...> wrote:
                          >
                          > Awesome discussion.
                          > As a newbie I am entitled to a couple dumb questions. ;-)
                          > I have a Peaberry 40,30,20.
                          > I have been struggling with testing out the TX. From what I have seen the filters do deserve a good look. In my testing 2nd and 3rd harmonics on 40 m were hardly attenuated. Building and testing filter filter got waylaid by getting software working on TX. :-(
                          > My biggest problem is getting the thing to transmit ia fashion suitable for testing.
                          > I was using HDSDR but have concluded its not really ready for transmit. I was trying to test on CW. Finally resorted to SSB and the whistle test. If I could only whistle.
                          >
                          > Briefly tried Rocky but seemed not to have much joy.
                          >
                          > I finally got PowerSDR-IQ running on RX. Have not got to TX yet but have not tried.
                          >
                          > So the question is. Can someone outline in some detail what software and method used to test TX on Ensemble RXTX (will work fine on Peaberry :-) ) ?
                          > I have the gear (dummy load, sampling Tap and Spec Analyzer) and knowledge to capture the data just too dumb to coax a continuous carrier out of the beast to capture.
                          >
                          > I have all the parts for the External Filter and will build it soon. I will sweep it when complete. I will post results. I got a VNWA3 for Christmas so I can post pretty pictures. ;-).
                          >
                          > Last question. Yes I know I may be exceeding number of allowable questions for the day. ;-)
                          > How much computing horsepower is required to run PowerSDR? I am using the version from the links on SdRBuzz? For testing on the bench I would like to use my old EEPC netbook. Will it work? HDSDR seemed to work on it. Ate they similar in computing requirements.
                          >
                          > Thanks all. Just amazed at the on air performance of the receiver. Like other have said after SDR it's hard to go back to no panadpter.
                          > Dave
                          > VE7PKE
                          >
                          >
                          >
                          > --- In softrock40@yahoogroups.com, "warrenallgyer" wrote:
                          > >
                          > > The first clue I had on the varying impedance issue was when I built the external filter breadboard to test the new values in the first place. I terminated on side of the test filter and then fed the MFJ directly into the other side, measuring the voltage across the termination on the scope. It was a sort of manual sweep generator and I could very quickly see when the output level started to drop off as I swept up through 11 MHz or so. In the process I noted that the VSWR indication on the old MFJ was very low, nearly 1:1 at 7 MHz and it started to rise rapidly in correspondence with the output level falling off at higher frequencies.
                          > >
                          > > Similarly I have noted in the past when tuning up my antenna tuner, using a scope on the input to the tuner as a power indicator, that the indicated voltage at the scope rises rapidly as the tuner VSWR goes up.
                          > >
                          > > I like Orin's characterization of "attenuation" in these filters. The power in those harmonics and the portion of the fundamental that gets "scraped off" by the filter is substantial and it is not heating the filter. It is being reflected back and dissipated in the finals and one indication of this appears to be a rise in the measured voltage at the filter input.
                          > >
                          > > I really do apologize for the tedium this subject has brought to some. Allen has it exactly right from my point of view in that this is a learning opportunity and my excitement at that gets a little overactive at times. I have learned a ton from what you guys have written in these exchanges and I hope those I have bored to tears can just make allowances and skip over the topic.
                          > >
                          > > Thanks again for a great discussion!
                          > >
                          > > Warren Allgyer - W8TOD
                          > >
                          > > --- In softrock40@yahoogroups.com, "Orin" wrote:
                          > > >
                          > > >
                          > > > --- In softrock40@yahoogroups.com, "allenbh57" wrote:
                          > > > >
                          > > > > Hi Tony, Warren and Alan,
                          > > > >
                          > > > > Very interesting discussion on the filters for 20-30-40. Warren, I
                          > > > liked your thought that the Z of the filter may not be the same in your
                          > > > test setup and the board, therefore the differences. Just for fun and
                          > > > related information (isn't information being fun one reason we do this?
                          > > > Hi Hi), would a VNA (don't have one available) or other suitable piece
                          > > > of equipment measure the impedance of the filters as a black-box?
                          > > >
                          > > >
                          > > > Yes, a VNA works fine for measuring the Z of the filter. You get
                          > > > something like this:
                          > > >
                          > > > VNWA scan of 15/12/10m filter
                          > > >
                          > > JzHAUEj7Cg?feat=directlink>
                          > > >
                          > > > though that's for the 15-12-10m build and I didn't have the actual
                          > > > impedance displayed. An antenna analyzer such as the MFJ 259B works
                          > > > too if you terminate the filter output in 50 ohms; it will display
                          > > > impedance, though the 259B doesn't give the sign of the reactive
                          > > > component.
                          > > >
                          > > >
                          > > > > For that matter, thinking off the top, could a directional coupler
                          > > > between the amp and the BPF be used to show what is happening here?
                          > > > Except that wold probably introduce another impedance into the mix.
                          > > > >
                          > > >
                          > > > About to wander slightly off topic here on what they don't tell you
                          > > > about filters; at least what they didn't tell me!
                          > > >
                          > > > That could work depending on what you have to look at the output from
                          > > > the coupler. What you should see with these filters is no (ideally)
                          > > > reverse power in the passband and for it to increase rapidly after the
                          > > > cutoff frequency. Yes, I don't think the amateur radio exams I've taken
                          > > > mention it, but this kind of filter doesn't do anything with input at
                          > > > frequencies higher than the cutoff frequency, they merely bounce it back
                          > > > to the source.
                          > > >
                          > > > Even though I might have said filter attenuation in the past, using the
                          > > > term 'attenuate' can be misleading. Unlike an attenuator where power
                          > > > that isn't passed through is turned into heat, these filters bounce the
                          > > > harmonics back to the PA! (Rather unfortunate when you select the wrong
                          > > > band/low pass filter on you amplifier. Say you leave you 40m LPF in and
                          > > > transmit on 20m, almost all your power bounces back. Hopefully the PA
                          > > > survives this abuse!) In the passband, there will be some slight
                          > > > attenuation due to losses in the coils and capacitors, but it's usually
                          > > > only a few tenths of a dB, depending on the Q of the coils and
                          > > > capacitors.
                          > > >
                          > > > Orin.
                          > > >
                          > >
                          >
                        • Alan
                          ... Subject: [softrock40] Re: Ensemble RXTX for 40/30/20 debate ... If you want a carrier why not use AM or FM with the mic gain right down? Works in HDSDR or
                          Message 12 of 25 , Mar 3, 2013
                          • 0 Attachment
                            ----- Original Message -----
                            Subject: [softrock40] Re: Ensemble RXTX for 40/30/20 debate


                            >I used to practice trying to whistle different tones when I worked repairing Motorola rigs years ago. But if you can't whistle,
                            >PowerSDR has a nice tone generator built right in!
                            >
                            > There may be some easier way to do this, but I used the Two Tone test feature in Setup. I'm using PowerSDR-IQ 2.4.4. Click on
                            > Setup, then go to the Tests tab. By default the tones are set to 700 and 1900 Hz. I set them both to the same value eg 1000 Hz.
                            >
                            > The MOX button will put the radio into transmit but minimal power is transmitted when you're on a Sideband mode, so that doesn't
                            > work unless you can figure out a way to whistle into your mic! (or get an audio tone generator)
                            >

                            If you want a carrier why not use AM or FM with the mic gain right down?
                            Works in HDSDR or PSDR.

                            73 Alan G4ZFQ
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