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HDSDR/Parallels update

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  • Dave Sublette
    Good evening, My Softrock Ensemble II is working perfectly using HDSDR running Parallels. I am using it to look at the IF output from my microwave
    Message 1 of 20 , Jun 1, 2014
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      Good evening,

      My Softrock Ensemble II is working perfectly using HDSDR running Parallels. I am using it to look at the IF output from my microwave transporters. The IF from the transporters is 144 MHz. I split that and send one side to my Elecraft K2 and the other side to the Ensemble II through a DEMI 144/28 INT transverter and run that to the Ensemble II.

      Both side look to be equally sensitive. The advantage of the Softrock is that I can see a 96 Khz slice of spectrum to look for signals that are off frequency. That saves a lot of tuning with the K2.

      It has been an interesting exercise. Thanks to all who have offered advice and help.

      73,

      Dave, K4TO
    • Zack Widup
      Transporters ? Autocorrect? ... 73, Zack W9SZ On 6/1/14, Dave Sublette k4to@bellsouth.net [softrock40]
      Message 2 of 20 , Jun 1, 2014
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        "Transporters"? Autocorrect?
        :-)

        73, Zack W9SZ

        On 6/1/14, Dave Sublette k4to@... [softrock40]
        <softrock40@yahoogroups.com> wrote:
        > Good evening,
        >
        > My Softrock Ensemble II is working perfectly using HDSDR running Parallels.
        > I am using it to look at the IF output from my microwave transporters. The
        > IF from the transporters is 144 MHz. I split that and send one side to my
        > Elecraft K2 and the other side to the Ensemble II through a DEMI 144/28 INT
        > transverter and run that to the Ensemble II.
        >
        > Both side look to be equally sensitive. The advantage of the Softrock is
        > that I can see a 96 Khz slice of spectrum to look for signals that are off
        > frequency. That saves a lot of tuning with the K2.
        >
        > It has been an interesting exercise. Thanks to all who have offered advice
        > and help.
        >
        > 73,
        >
        > Dave, K4TO
      • warrenallgyer
        Dave Just out of curiosity because I own one.... would the Ensemble RXII VHF work in this application? And could you not eliminate the 144/28 transverter this
        Message 3 of 20 , Jun 2, 2014
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          Dave

          Just out of curiosity because I own one.... would the Ensemble RXII VHF work in this application? And could you not eliminate the 144/28 transverter this way?

          Warren Allgyer
          9V1TD
        • Dave Sublette
          NAWù I got me one of them Star Trek things, ;-) Dave ... NAWù I got me one of them Star Trek things, ;-) Dave On Jun 1, 2014, at 11:31 PM, Zack Widup
          Message 4 of 20 , Jun 2, 2014
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            NAW— I got me one of them Star Trek things,  ;-)

            Dave

            On Jun 1, 2014, at 11:31 PM, Zack Widup w9sz.zack@... [softrock40] <softrock40@yahoogroups.com> wrote:

            "Transporters"? Autocorrect?
            :-)

            73, Zack W9SZ

            On 6/1/14, Dave Sublette k4to@... [softrock40]
            <softrock40@yahoogroups.com> wrote:
            > Good evening,
            >
            > My Softrock Ensemble II is working perfectly using HDSDR running Parallels.
            > I am using it to look at the IF output from my microwave transporters. The
            > IF from the transporters is 144 MHz. I split that and send one side to my
            > Elecraft K2 and the other side to the Ensemble II through a DEMI 144/28 INT
            > transverter and run that to the Ensemble II.
            >
            > Both side look to be equally sensitive. The advantage of the Softrock is
            > that I can see a 96 Khz slice of spectrum to look for signals that are off
            > frequency. That saves a lot of tuning with the K2.
            >
            > It has been an interesting exercise. Thanks to all who have offered advice
            > and help.
            >
            > 73,
            >
            > Dave, K4TO


          • Dave Sublette
            GM Warren I am thinking I could do this. The E RXII VHF wasnÆt available when I built the E II HF. I can tell you that the present transverter has a noise
            Message 5 of 20 , Jun 2, 2014
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              GM Warren

              I am thinking I could do this. The E RXII VHF wasn’t available when I built the E II HF. I can tell you that the present transverter has a noise figure of 4.5 dB and 0 dB gain…. that’s the way it is designed. If the E RXII VHF will match that NF, it should do the job. My HP8970A NF meter will measure NF directly to 1500 Mhz. I should build one and try it.

              Is there anyone who has measured the NF of the E RX II or are there published specs? I haven’t looked to see.

              Dave

              On Jun 2, 2014, at 3:03 AM, allgyer@... [softrock40] <softrock40@yahoogroups.com> wrote:

              > Dave
              >
              > Just out of curiosity because I own one.... would the Ensemble RXII VHF work in this application? And could you not eliminate the 144/28 transverter this way?
              >
              > Warren Allgyer
              > 9V1TD
            • warrenallgyer
              Now you have done it! For 40 years I have been trying to understand NF..... and I never had the equipment nor the time to try to figure it out or measure it.
              Message 6 of 20 , Jun 2, 2014
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                Now you have done it!

                For 40 years I have been trying to understand NF..... and I never had the equipment nor the time to try to figure it out or measure it. Now I have both..... and no excuses.

                Going to read up on it then do it...... back soon with my results.

                WA
                9V1TD
              • Dave Sublette
                IsnÆt that another great thing about these discussion groups! One guy will say something and it spurs another to learn! My meager knowledge of nf is that it
                Message 7 of 20 , Jun 2, 2014
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                  Isn’t that another great thing about these discussion groups! One guy will say something and it spurs another to learn!

                  My meager knowledge of nf is that it measures how much additional noise is added by your receiving system to the noise seen by the antenna.  It is most useful and critical to know this for VHF and up, where atmospheric noise is not as high and system noise is a more significant factor in how weak of a signal you can hear.  Man made noise is always a factor. If we are lucky, we live in an electrically quiet location.

                  Good luck with you studies.

                  Dave


                  On Jun 2, 2014, at 7:54 AM, allgyer@... [softrock40] <softrock40@yahoogroups.com> wrote:

                  Now you have done it!

                  For 40 years I have been trying to understand NF..... and I never had the equipment nor the time to try to figure it out or measure it. Now I have both..... and no excuses. 

                  Going to read up on it then do it...... back soon with my results.

                  WA
                  9V1TD


                • warrenallgyer
                  Haha Dave. You are right on! So the way I read it, NF is directly related to and derived from MDS. NF = MDS - (10 log (BW) - 174) dB -10 log BW - 174 in a 500
                  Message 8 of 20 , Jun 2, 2014
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                    Haha Dave. You are right on!

                    So the way I read it, NF is directly related to and derived from MDS.

                    NF = MDS - (10 log (BW) - 174) dB


                    -10 log BW - 174 in a 500 Hz passband, which is what is used to determine MDS = 147. (Man! I hate math!)


                    So, my RXII VHF has an MDS of -103 dB (ouch!) which means a NF of 44 dB, which means it is stone deaf, which means I messed up something when I built it over a year ago and am just finding out now.


                    Thanks a LOT guys!


                    Warren Allgyer

                    9V1TD

                  • Dave Sublette
                    Sure sounds like a problem to me. I would look to see if all the components are properly soldered from the LO to detector. I also had to do some crossing of
                    Message 9 of 20 , Jun 2, 2014
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                      Sure sounds like a problem to me.  I would look to see if all the components are properly soldered from the LO to detector.  I also had to do some crossing of wires from various interstage coupling transformers — e.g. input from antenna and LO coupling transformer.

                      If it turns out that it really is that deaf, a preamp stage should fix it.  

                      BTW, how did you measure nf?  My HP8970 puts noise into the input jack and looks at the output, either on the same frequency, if it is a device between 10 -1500 Mhz.  Or, it has a mode to look at a different output frequency, as in the case of a transverter.  With the Soft rock, the output is audio!  I don’t think I can use the HP that way.

                      Dave


                      On Jun 2, 2014, at 8:33 AM, allgyer@... [softrock40] <softrock40@yahoogroups.com> wrote:

                      Haha Dave. You are right on!

                      So the way I read it, NF is directly related to and derived from MDS. 

                      NF = MDS - (10 log (BW) - 174) dB 


                      -10 log BW - 174 in a 500 Hz passband, which is what is used to determine MDS = 147. (Man! I hate math!)


                      So, my RXII VHF has an MDS of -103 dB (ouch!) which means a NF of 44 dB, which means it is stone deaf, which means I messed up something when I built it over a year ago and am just finding out now.


                      Thanks a LOT guys!


                      Warren Allgyer

                      9V1TD



                    • Dave Sublette
                      Well DUH! I re-read your email .. you just measure MDS and do the math :-) Dave
                      Message 10 of 20 , Jun 2, 2014
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                        Well DUH! I re-read your email .. you just measure MDS and do the math :-)
                        Dave
                        On Jun 2, 2014, at 8:33 AM, allgyer@... [softrock40] <softrock40@yahoogroups.com> wrote:

                        Haha Dave. You are right on!

                        So the way I read it, NF is directly related to and derived from MDS. 

                        NF = MDS - (10 log (BW) - 174) dB 


                        -10 log BW - 174 in a 500 Hz passband, which is what is used to determine MDS = 147. (Man! I hate math!)


                        So, my RXII VHF has an MDS of -103 dB (ouch!) which means a NF of 44 dB, which means it is stone deaf, which means I messed up something when I built it over a year ago and am just finding out now.


                        Thanks a LOT guys!


                        Warren Allgyer

                        9V1TD



                      • Alan
                        Original Message ----- Subject: Re: [softrock40] Re: HDSDR/Parallels update ... Dave, Look in the Files area. I feel sure Bob, G8VOI, did that. As I recall the
                        Message 11 of 20 , Jun 2, 2014
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                          Original Message -----
                          Subject: Re: [softrock40] Re: HDSDR/Parallels update


                          >Is there anyone who has measured the NF of the E RX II or are there published specs? I haven’t looked to see.

                          Dave,

                          Look in the Files area. I feel sure Bob, G8VOI, did that.
                          As I recall the figures were good, mine works well although it is a while since I used it.

                          73 Alan G4ZFQ
                        • warrenallgyer
                          Well I found 35 dB of loss between the IF output of the mixer and the QSD...... that would make up a lot of it! It appears that what should be a series
                          Message 12 of 20 , Jun 2, 2014
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                            Well I found 35 dB of loss between the IF output of the mixer and the QSD...... that would make up a lot of it! It appears that what should be a series resonant circuit of L4 and C15 isn't.... probably because C15 appears to be an unrecognizable value when it should be 82 pf. You would think, after 8 Softrocks kits there would be an 82 pf cap in the leftover parts drawer... but it appears there is not.

                            Off to the parts store at lunch tomorrow. The REAL NF of the RX VHF will have to wait another day.

                            Warren Allgyer
                            9V1TD
                          • warrenallgyer
                            Thanks for the pointer Alan. I found Bob s file here: Yahoo Groups https://groups.yahoo.com/neo/groups/softrock40/files/G8VOI/ His definition of MDS does not
                            Message 13 of 20 , Jun 2, 2014
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                              Thanks for the pointer Alan. I found Bob's file here:

                              Yahoo Groups

                              His definition of MDS does not conform with the ARRL  method so there is a little ambiguity there. Bob looked at MDS as the minimum visible signal above the noise floor on WinradHD with a 2.4 KHz filter bandwidth. By those criteria he recorded MDS of -140 dBm. If that were the real MDS then the NF would be 7 dB..... not as good as the transverter. I suspect that "real" MDS would be somewhat worse if measured as 3 dB S+N/N since I usually see a several dB signal spike above the noise floor at this point. I normally have RBW sitting at 1.5 Hz but it does not affect the ARRL measurement, only the visual display.

                              More info to come when I find that 82 pf cap!

                              Warren Allgyer
                              9V1TD

                               

                            • warrenallgyer
                              OK.... 82 pf cap replaced (actually used a 68 and a 15 from the junk box in parallel, no patience for shopping today) and the IF response is back to normal.
                              Message 14 of 20 , Jun 3, 2014
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                                OK.... 82 pf cap replaced (actually used a 68 and a 15 from the junk box in parallel, no patience for shopping today) and the IF response is back to normal. Tuned everything up and I just completed MDS measurements and I don't quite believe my numbers. So I will explain my methodology and maybe someone can tell me if I did it wrong:

                                MDS: -143 - 144 dBm
                                NF: 2-3 dB

                                If it is real I think I should be happy with it. Here is how I got there:

                                Signal generator with pads producing -57 dBm as displayed on the spectrum analyzer.

                                Unplugged from the S/A and input the the RX running HDSDR.

                                Calibrated HDSDR to read -57 dBm with the S- meter calibration.

                                HDSDR in CW mode with the filter 3 dB points set at plus and minus 250 Hz

                                Audio output from HDSDR into an RMS voltmeter

                                Attenuated the signal until there was a 3 dB difference indicated on the meter when  the signal was in the passband as compared to when I flicked the tuning 10 KHz off.

                                Read the indicated signal level on the HDSDR scale at -143 to -144 dBm

                                The noise figure constant for a 500 Hz passband is 147. 147 plus -144 equals a 3 dB noise figure.

                                For reference purposes, I was reading the -144 dBm in the small lower right window with the RBW set to 1.5 Hz. With these settings the visible noise floor was sitting at -159 dBm so the "MDS" signal was a spike  a full 15 dB above the visible noise floor at this RBW.

                                Lots of numbers but I would love to hear if someone thinks I missed something or did something wrong. If not, then I think this is a pretty good little receiver.

                                Warren Allgyer
                                9V1TD
                              • Dave Sublette
                                Good morning Warren, This Softrock Ensemble II Hf is working so well, now that I fixed the downconverter feeding it! I wonder if it ever worked correctly!
                                Message 15 of 20 , Jun 4, 2014
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                                  Good morning Warren,

                                  This Softrock Ensemble II Hf is working so well, now that I fixed the downconverter feeding it! I wonder if it ever worked correctly! I’m fighting the urge to buy the VHF kit. I have too many projects going at the moment.

                                  73,

                                  Dave


                                  On Jun 3, 2014, at 8:49 AM, allgyer@... [softrock40] <softrock40@yahoogroups.com> wrote:
                                • warrenallgyer
                                  Good morning/Good evening Dave That is great to hear. It is funny because I am feeling the same way about my VHF now that I recovered the 35 dB lost in the IF!
                                  Message 16 of 20 , Jun 4, 2014
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                                    Good morning/Good evening Dave

                                    That is great to hear. It is funny because I am feeling the same way about my VHF now that I recovered the 35 dB lost in the IF! Having so much fun that I was a click away from ordering another one for six meters last night and still may after another glass of wine tonight. As you may have seen, the performance seems excellent. I am sitting here listening to a repeater in Malaysia on 146.3 using just a 19" piece of wire taped to my apartment window. On a whim I re-tuned it down to 120.3 to listen to Changi Approach at the airport (STRICTLY verboten to do this in Singapore) and, while I lost most the 35 dB again in the re-tune, I could clearly hear both the tower and the aircraft on approach. I never realized those guys are using AM! Seems very archaic. Anyway, HDSDR seems to work equally well on AM, SSB, CW, and FM.

                                    Do it! Get the VHF. It is the price of dinner for one at a nice place, dinner for two at a regular one.

                                    Good luck Dave!

                                    Warren Allgyer
                                    9V1TD
                                  • MICHAEL TALLENT
                                    The pre-amp device is a dual gate Mos Fet BF991 and has a noise spec of max 2DB at 200 MHz, typical of 1 DB NF. So this level of performance would not be
                                    Message 17 of 20 , Jun 4, 2014
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                                      The pre-amp device is a dual gate Mos Fet BF991 and has a noise spec of max 2DB at 200 MHz, typical of 1 DB NF.  So this level of performance would not be unexpected.
                                       
                                      I don’t know what type of RMS meter you are using but it is measuring the full spectrum, noise from the audio circuit.  It might be worth a check to see what your RMS meter measures with the SDR disconnected from the sound input.
                                       
                                      I hope to join the fray soon as I am updating my LAB by upgrading from 1960’s to 1980’s spectrum analyzers, that is HP-141T types to HP-8566B and HP-8568 SA’s.
                                       
                                      Mike  W6MXV  in  KY
                                       
                                      Sent: Tuesday, June 03, 2014 8:49 AM
                                      Subject: Re: [softrock40] Re: HDSDR/Parallels update
                                       


                                      OK.... 82 pf cap replaced (actually used a 68 and a 15 from the junk box in parallel, no patience for shopping today) and the IF response is back to normal. Tuned everything up and I just completed MDS measurements and I don't quite believe my numbers. So I will explain my methodology and maybe someone can tell me if I did it wrong:

                                      MDS: -143 - 144 dBm
                                      NF: 2-3 dB

                                      If it is real I think I should be happy with it. Here is how I got there:

                                      Signal generator with pads producing -57 dBm as displayed on the spectrum analyzer.

                                      Unplugged from the S/A and input the the RX running HDSDR.

                                      Calibrated HDSDR to read -57 dBm with the S- meter calibration.

                                      HDSDR in CW mode with the filter 3 dB points set at plus and minus 250 Hz

                                      Audio output from HDSDR into an RMS voltmeter

                                      Attenuated the signal until there was a 3 dB difference indicated on the meter when  the signal was in the passband as compared to when I flicked the tuning 10 KHz off.

                                      Read the indicated signal level on the HDSDR scale at -143 to -144 dBm

                                      The noise figure constant for a 500 Hz passband is 147. 147 plus -144 equals a 3 dB noise figure.

                                      For reference purposes, I was reading the -144 dBm in the small lower right window with the RBW set to 1.5 Hz. With these settings the visible noise floor was sitting at -159 dBm so the "MDS" signal was a spike  a full 15 dB above the visible noise floor at this RBW.

                                      Lots of numbers but I would love to hear if someone thinks I missed something or did something wrong. If not, then I think this is a pretty good little receiver.

                                      Warren Allgyer
                                      9V1TD

                                      Posted by: allgyer@...

                                    • warrenallgyer
                                      Hi Michael Thanks for the input. The RMS voltmeter is an Amber 3500 Distortion and Noise Analyzer Set, a relic of the 80s that I restored from my time then as
                                      Message 18 of 20 , Jun 4, 2014
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                                        Hi Michael

                                        Thanks for the input. The RMS voltmeter is an Amber 3500 Distortion and Noise Analyzer Set, a relic of the 80s that I restored from my time then as a television chief engineer in San Francisco. It is old technology but a very useful toy.

                                        I tried to make my measurements with the SDR volume control set so that the noise level was at about -20 dBV and at that level the background noise was at least 20 dB down with the SDR disconnected so I think it was not a factor. The Amber allows me to lo cut the audio spectrum at 400 Hz and hi cut at 50 KHz. The measurements were made with these filters in but the baseline difference with them in or out was less than half a dB.

                                        Warren Allgyer
                                        9V1TD
                                      • MICHAEL TALLENT
                                        OK, A Chief TV Engr, maybe you used some of my inventions, Digital Time Base Corrector. I started 3 companies in SF Bay area 1970’s 1980’s, CVS, ADDA
                                        Message 19 of 20 , Jun 4, 2014
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                                          OK, A Chief TV Engr, maybe you used some of my inventions, Digital Time Base Corrector.  I started 3 companies in SF Bay area 1970’s 1980’s, CVS, ADDA Corp. and ALTA Group.  I want to thank you for the interesting measurements, got me more interested in making measurements also.
                                           
                                          Mike  W6MXV
                                           
                                          Sent: Wednesday, June 04, 2014 6:44 PM
                                          Subject: Re: [softrock40] Re: HDSDR/Parallels update
                                           


                                          Hi Michael

                                          Thanks for the input. The RMS voltmeter is an Amber 3500 Distortion and Noise Analyzer Set, a relic of the 80s that I restored from my time then as a television chief engineer in San Francisco. It is old technology but a very useful toy.

                                          I tried to make my measurements with the SDR volume control set so that the noise level was at about -20 dBV and at that level the background noise was at least 20 dB down with the SDR disconnected so I think it was not a factor. The Amber allows me to lo cut the audio spectrum at 400 Hz and hi cut at 50 KHz. The measurements were made with these filters in but the baseline difference with them in or out was less than half a dB.

                                          Warren Allgyer
                                          9V1TD
                                        • warrenallgyer
                                          Mike I spent 3 weeks inside a CVS-504 on the workbench in Cleveland. I had finished a minor repair on the 3-layer sandwich that was the A-D converter, and was
                                          Message 20 of 20 , Jun 4, 2014
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                                            Mike

                                            I spent 3 weeks inside a CVS-504 on the workbench in Cleveland. I had finished a minor repair on the 3-layer sandwich that was the A-D converter, and was in the process of verifying it on the extender. While chatting with a colleague across the bench I plugged it in upside down reversing, (from memory now) the + and - 24V supplies and pretty much trashing the board. The next 3 weeks were spent doing component level repairs on the devastation!

                                            I now run Strategic Account sales for Miranda/Grass Valley here in Singapore. Still cannot keep my fingers off the toys though.

                                            Warren Allgyer
                                            9V1TD
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