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Raspberry Pi as WSPR transmitter up to 250Mhz

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  • Guido
    There is now a modified version of Dan s, WsprryPi that should be capable transmitting WSPR on HF and VHF bands, just with a LPF and antenna connected to
    Message 1 of 25 , Mar 20, 2013
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      There is now a modified version of Dan's, WsprryPi that should be capable transmitting WSPR on HF and VHF bands, just with a LPF and antenna connected to GPIO4.

      For experimentation, my code and binary can be found here: https://github.com/threeme3/WsprryPi

      73, Guido
      PE1NNZ

      On Sun, Mar 17, 2013 at 8:11 PM, Daniel Ankers <md1clv@...> wrote:

      > you will see that it is possible to use the Pi as an FM Tx without any
      > additional components other than a piece of wire for an aerial.
      >
      There is also https://github.com/DanAnkers/WsprryPi which uses the same
      technique (or to be more accurate, reuses the code!) to produce WSPR on LF
      with only a low pass filter and an antenna.

      Regards,
      Dan MD1CLV
    • Ronny Julian
      As one that wants to try this copying the mail, whats and LPF?
      Message 2 of 25 , Mar 20, 2013
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        As one that wants to try this copying the mail, whats and LPF?

        On Wed, Mar 20, 2013 at 11:18 AM, Guido <threeme3@...> wrote:
         

        There is now a modified version of Dan's, WsprryPi that should be capable transmitting WSPR on HF and VHF bands, just with a LPF and antenna connected to GPIO4.

        For experimentation, my code and binary can be found here: https://github.com/threeme3/WsprryPi

        73, Guido
        PE1NNZ

        On Sun, Mar 17, 2013 at 8:11 PM, Daniel Ankers <md1clv@...> wrote:

        > you will see that it is possible to use the Pi as an FM Tx without any
        > additional components other than a piece of wire for an aerial.
        >
        There is also https://github.com/DanAnkers/WsprryPi which uses the same
        technique (or to be more accurate, reuses the code!) to produce WSPR on LF
        with only a low pass filter and an antenna.

        Regards,
        Dan MD1CLV


      • Ray Wells
        LPF = Low Pass Filter. It s purpose is to allow the wanted frequency pass to the antenna but attenuate all harmonics and other unwanted rubbish in the spectrum
        Message 3 of 25 , Mar 20, 2013
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          LPF = Low Pass Filter. It's purpose is to allow the wanted frequency pass to the antenna but attenuate all harmonics and other unwanted rubbish in the spectrum above the wanted frequency.



          Ray vk2tv

          On 21/03/13 12:25, Ronny Julian wrote:
           

          As one that wants to try this copying the mail, whats and LPF?

          On Wed, Mar 20, 2013 at 11:18 AM, Guido <threeme3@...> wrote:
           
          There is now a modified version of Dan's, WsprryPi that should be capable transmitting WSPR on HF and VHF bands, just with a LPF and antenna connected to GPIO4.

          For experimentation, my code and binary can be found here: https://github.com/threeme3/WsprryPi

          73, Guido
          PE1NNZ

          On Sun, Mar 17, 2013 at 8:11 PM, Daniel Ankers <md1clv@...> wrote:

          > you will see that it is possible to use the Pi as an FM Tx without any
          > additional components other than a piece of wire for an aerial.
          >
          There is also https://github.com/DanAnkers/WsprryPi which uses the same
          technique (or to be more accurate, reuses the code!) to produce WSPR on LF
          with only a low pass filter and an antenna.

          Regards,
          Dan MD1CLV


        • Ronny Julian
          This I have to try!
          Message 4 of 25 , Mar 20, 2013
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            This I have to try! 

            On Wed, Mar 20, 2013 at 11:56 PM, Ray Wells <vk2tv@...> wrote:
             

            LPF = Low Pass Filter. It's purpose is to allow the wanted frequency pass to the antenna but attenuate all harmonics and other unwanted rubbish in the spectrum above the wanted frequency.



            Ray vk2tv


            On 21/03/13 12:25, Ronny Julian wrote:
             

            As one that wants to try this copying the mail, whats and LPF?

            On Wed, Mar 20, 2013 at 11:18 AM, Guido <threeme3@...> wrote:
             
            There is now a modified version of Dan's, WsprryPi that should be capable transmitting WSPR on HF and VHF bands, just with a LPF and antenna connected to GPIO4.

            For experimentation, my code and binary can be found here: https://github.com/threeme3/WsprryPi

            73, Guido
            PE1NNZ

            On Sun, Mar 17, 2013 at 8:11 PM, Daniel Ankers <md1clv@...> wrote:

            > you will see that it is possible to use the Pi as an FM Tx without any
            > additional components other than a piece of wire for an aerial.
            >
            There is also https://github.com/DanAnkers/WsprryPi which uses the same
            technique (or to be more accurate, reuses the code!) to produce WSPR on LF
            with only a low pass filter and an antenna.

            Regards,
            Dan MD1CLV



          • Stephen
            Guys, I ll be meeting up with Guido tomorrow for a couple of days to discuss, among other things, production of a kit o parts for a set of Low Pass Filters
            Message 5 of 25 , Mar 21, 2013
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              Guys,

              I'll be meeting up with Guido tomorrow for a couple of days to discuss, among other things, production of a "kit o parts" for a set of Low Pass Filters which can be switched from the Pi plus a small on board Power Amplifier.

              You need a Low Pass Filter on the output of the Pi to stop it transmitting the harmonics of the programmed output frequency. The Pi puts out a square wave rich in harmonics. To find out more about this topic see here :-

              http://electronics.stackexchange.com/questions/32310/what-exactly-are-harmonics-and-how-do-they-appear


              For a discussion about how to make one you can do no better than here :-

              http://www.interalia.plus.com/q_tech2.htm

              Toroids and capacitors can be bought from a fellow ham here :-

              http://www.kitsandparts.com

              If Guido and I decide to do some kits for a multi band LPF and PA board we will let you know



              Hope this helps,

              73s Steve G0XAR



              --- In Raspberry_Pi_4-Ham_RADIO@yahoogroups.com, Ray Wells <vk2tv@...> wrote:
              >
              > LPF = Low Pass Filter. It's purpose is to allow the wanted frequency
              > pass to the antenna but attenuate all harmonics and other unwanted
              > rubbish in the spectrum above the wanted frequency.
              >
              >
              >
              > Ray vk2tv
              >
              > On 21/03/13 12:25, Ronny Julian wrote:
              > >
              > > As one that wants to try this copying the mail, whats and LPF?
              > >
              > > On Wed, Mar 20, 2013 at 11:18 AM, Guido <threeme3@...
              > > <mailto:threeme3@...>> wrote:
              > >
              > > There is now a modified version of Dan's, WsprryPi that should be
              > > capable transmitting WSPR on HF and VHF bands, just with a LPF and
              > > antenna connected to GPIO4.
              > >
              > > For experimentation, my code and binary can be found here:
              > > https://github.com/threeme3/WsprryPi
              > >
              > > 73, Guido
              > > PE1NNZ
              > >
              > > On Sun, Mar 17, 2013 at 8:11 PM, Daniel Ankers <md1clv@...
              > > <mailto:md1clv@...>> wrote:
              > >
              > >
              > > > you will see that it is possible to use the Pi as an FM Tx
              > > without any
              > > > additional components other than a piece of wire for an aerial.
              > > >
              > > There is also https://github.com/DanAnkers/WsprryPi which uses
              > > the same
              > > technique (or to be more accurate, reuses the code!) to
              > > produce WSPR on LF
              > > with only a low pass filter and an antenna.
              > >
              > > Regards,
              > > Dan MD1CLV
              > >
              > >
              > >
              >
            • Ronny Julian
              Stephen you might take a page out of the 4 States QRP group book and make everything part of the board for a 30 or 40 meter version. Seen this?
              Message 6 of 25 , Mar 21, 2013
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                Stephen you might take a page out of the 4 States QRP group book and make everything part of the board for a 30 or 40  meter version.  Seen this?

                Look forward to what you come up with.
                Ronny
                K4RJJ



                On Thu, Mar 21, 2013 at 4:51 AM, Stephen <squirrox@...> wrote:
                 

                Guys,

                I'll be meeting up with Guido tomorrow for a couple of days to discuss, among other things, production of a "kit o parts" for a set of Low Pass Filters which can be switched from the Pi plus a small on board Power Amplifier.

                You need a Low Pass Filter on the output of the Pi to stop it transmitting the harmonics of the programmed output frequency. The Pi puts out a square wave rich in harmonics. To find out more about this topic see here :-

                http://electronics.stackexchange.com/questions/32310/what-exactly-are-harmonics-and-how-do-they-appear

                For a discussion about how to make one you can do no better than here :-

                http://www.interalia.plus.com/q_tech2.htm

                Toroids and capacitors can be bought from a fellow ham here :-

                http://www.kitsandparts.com

                If Guido and I decide to do some kits for a multi band LPF and PA board we will let you know

                Hope this helps,

                73s Steve G0XAR



                --- In Raspberry_Pi_4-Ham_RADIO@yahoogroups.com, Ray Wells <vk2tv@...> wrote:
                >
                > LPF = Low Pass Filter. It's purpose is to allow the wanted frequency
                > pass to the antenna but attenuate all harmonics and other unwanted
                > rubbish in the spectrum above the wanted frequency.
                >
                >
                >
                > Ray vk2tv
                >
                > On 21/03/13 12:25, Ronny Julian wrote:
                > >
                > > As one that wants to try this copying the mail, whats and LPF?
                > >
                > > On Wed, Mar 20, 2013 at 11:18 AM, Guido <threeme3@...
                > > <mailto:threeme3@...>> wrote:
                > >
                > > There is now a modified version of Dan's, WsprryPi that should be
                > > capable transmitting WSPR on HF and VHF bands, just with a LPF and
                > > antenna connected to GPIO4.
                > >
                > > For experimentation, my code and binary can be found here:
                > > https://github.com/threeme3/WsprryPi
                > >
                > > 73, Guido
                > > PE1NNZ
                > >
                > > On Sun, Mar 17, 2013 at 8:11 PM, Daniel Ankers <md1clv@...
                > > <mailto:md1clv@...>> wrote:
                > >
                > >
                > > > you will see that it is possible to use the Pi as an FM Tx
                > > without any
                > > > additional components other than a piece of wire for an aerial.
                > > >
                > > There is also https://github.com/DanAnkers/WsprryPi which uses
                > > the same
                > > technique (or to be more accurate, reuses the code!) to
                > > produce WSPR on LF
                > > with only a low pass filter and an antenna.
                > >
                > > Regards,
                > > Dan MD1CLV
                > >
                > >
                > >
                >


              • Stephen
                Actually I have the 4 States Class E TX kit in the shack ready to make. But 5 watts is a bit QRO for a QRSS/WSPR beacon. However the companion RX from the guys
                Message 7 of 25 , Mar 21, 2013
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                  Actually I have the 4 States Class E TX kit in the shack ready to make. But 5 watts is a bit QRO for a QRSS/WSPR beacon. However the companion RX from the guys at 4 States QRP is brilliant and if anyone here wants a good 40 meters narrow band RX I will shamelessly recommend it.

                  73s Steve G0XAR
                • Eldon Brown
                  OK, here is my lash up with 30m LPF, http://wa0uwh.blogspot.com/2013/03/rpi-as-wspr-beacon-with-pa47.html Thanks Dan, for the neat program. Regards, Eldon
                  Message 8 of 25 , Mar 21, 2013
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                    OK, here is my lash up with 30m LPF,  http://wa0uwh.blogspot.com/2013/03/rpi-as-wspr-beacon-with-pa47.html

                    Thanks Dan, for the neat program.


                    Regards,
                    Eldon Brown

                    73 - Eldon - WA0UWH - CN88xc - http://WA0UWH.blogspot.com/




                    On Wed, Mar 20, 2013 at 10:54 PM, Ronny Julian <k4rjjradio@...> wrote:
                     

                    This I have to try! 



                    On Wed, Mar 20, 2013 at 11:56 PM, Ray Wells <vk2tv@...> wrote:
                     

                    LPF = Low Pass Filter. It's purpose is to allow the wanted frequency pass to the antenna but attenuate all harmonics and other unwanted rubbish in the spectrum above the wanted frequency.



                    Ray vk2tv


                  • Rick Simpson
                    Eldon, I just visited your site and discovered the Open QRP project. Are kits still available? Is the project still alive? Rick K3IND
                    Message 9 of 25 , Mar 21, 2013
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                      Eldon,
                       
                      I just visited your site and discovered the Open QRP project. Are kits still available? Is the project still alive?
                       
                      Rick
                      K3IND
                    • psk31
                      This sounded interesting, I just had to give it a try. Here are some preliminary tests of the RasPi for generating WSPR on the carrier frequency. Tests in
                      Message 10 of 25 , Mar 25, 2013
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                        This sounded interesting, I just had to give it a try.
                        Here are some preliminary tests of the RasPi for generating WSPR on the carrier frequency.
                        Tests in order of Frequency :-

                        475.700KHz.
                        Spurious signals spaced at 100Hz intervals either side of the wanted frequency would preclude its use on this band and would make it unsuitable for feeding an amplifier. An LPF or indeed any filter would not cure this problem.
                        The level of the closest spurri was not measured as strangely, after 1Hour of test, decoding stopped (not a timing problem) and the RasPi has never produced a decodeable signal again on this frequency.

                        1.838100MHz
                        Frequencies in this range gave warnings that Symbols were out of range of the fractional divider.

                        3.594100MHz
                        Signals produced decodes but the 100Hz images were numerous  and the nearest on either side were only -2dB compared to the wanted.

                        7.040100MHz
                        Signals decoded, the 100Hz images on either side of the wanted were -19dB

                        10.140200MHz
                        Signals decoded, the 100Hz images were well down, the one above the wanted frequency is the strongest at -29dB. This should be quite useable for QRP. The RasPi has run WsprryPi successfully for over 3 Hours.

                        Tests are continuing.

                        73 Eddie G3ZJO


                        On 20/03/2013 15:18, Guido wrote:  
                        There is now a modified version of Dan's, WsprryPi that should be capable transmitting WSPR on HF and VHF bands, just with a LPF and antenna connected to GPIO4.

                        For experimentation, my code and binary can be found here: https://github.com/threeme3/WsprryPi

                        73, Guido
                        PE1NNZ

                        On Sun, Mar 17, 2013 at 8:11 PM, Daniel Ankers <md1clv@...> wrote:

                        > you will see that it is possible to use the Pi as an FM Tx without any
                        > additional components other than a piece of wire for an aerial.
                        >
                        There is also https://github.com/DanAnkers/WsprryPi which uses the same
                        technique (or to be more accurate, reuses the code!) to produce WSPR on LF
                        with only a low pass filter and an antenna.

                        Regards,
                        Dan MD1CLV

                      • psk31
                        Further tests I meant to mention in my last post that an essential test will be to power the RasPi from a linear PSU or ideally a battery to see if any of the
                        Message 11 of 25 , Mar 25, 2013
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                          Further tests
                          I meant to mention in my last post that an essential test will be to power the RasPi from a linear PSU or ideally a battery to see if any of the 100Hz and 50Hz spurii are improved.

                          14.095600MHz
                          Signals decoded 100Hz spurii -23dB

                          18.106100MHz
                          Signals decoded spurii -25dB. Further investigation needed there is another group of signals a few KHz above the wanted signal.

                          21.096100MHz
                          Signals decoded spurii -23dB.

                          24.926100MHz
                          Signals decoded spurri +/- 100Hz -30dB

                          28.126100MHz
                          Signals decoded spurii +/- 100 Hz -25dB

                          50.294500MHz
                          RX not connected to a computer signal audibly broad and distorted. Further investigation needed.

                          144.490500MHz
                          No decodes. Signal wide, distorted, with a ripple and clicks.


                          On 25/03/2013 12:14, psk31 wrote:
                           

                          This sounded interesting, I just had to give it a try.
                          Here are some preliminary tests of the RasPi for generating WSPR on the carrier frequency.
                          Tests in order of Frequency :-

                          475.700KHz.
                          Spurious signals spaced at 100Hz intervals either side of the wanted frequency would preclude its use on this band and would make it unsuitable for feeding an amplifier. An LPF or indeed any filter would not cure this problem.
                          The level of the closest spurri was not measured as strangely, after 1Hour of test, decoding stopped (not a timing problem) and the RasPi has never produced a decodeable signal again on this frequency.

                          1.838100MHz
                          Frequencies in this range gave warnings that Symbols were out of range of the fractional divider.

                          3.594100MHz
                          Signals produced decodes but the 100Hz images were numerous  and the nearest on either side were only -2dB compared to the wanted.

                          7.040100MHz
                          Signals decoded, the 100Hz images on either side of the wanted were -19dB

                          10.140200MHz
                          Signals decoded, the 100Hz images were well down, the one above the wanted frequency is the strongest at -29dB. This should be quite useable for QRP. The RasPi has run WsprryPi successfully for over 3 Hours.

                          Tests are continuing.

                          73 Eddie G3ZJO



                        • Guido
                          Good morning Eddie, et al, Thanks all for your interest in this project and performing these tests. A good USB power supply is required to prevent 100 Hz side
                          Message 12 of 25 , Mar 26, 2013
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                            Good morning Eddie, et al,

                            Thanks all for your interest in this project and performing these tests.
                            A good USB power supply is required to prevent 100 Hz side bands. 
                            Most probably this 100Hz created in the rectification stage of your USB 
                            power supply and then mixed with the clock signal on GPIO4. I am 
                            interested to know you measurement results when using another regulated 
                            power supply.

                            The PLL fractional divider stage in the RPi and the alternation algorithm in 
                            WsprryPi are other potential sources of spurs. I found that increasing the 
                            clock of modulating the fractional divider reduces the number of spurs, 
                            especially on higher frequencies (30MHz and up); but unfortunately it also 
                            decrease the frequency resolution making below the required WSPR 
                            symbol bandwidth. If you like to measure spuri, please try my new version 
                            If you change n_iter value in code and re-compile, you may try 50 and 70Mhz, 
                            it is currently blocked.

                            The new version has also a feature that lets you control the duty cycle of 
                            your TX; a set of frequencies can be added where 0 frequency stands for
                            a two minute interval where TX is disabled. E.g 25% duty cycle:

                                  sudo ./wspr G3ZJO FN20 10 7040074 0 0 0

                            73, Guido
                            PE1NNZ
                          • psk31
                            Good Morning Guido / All Thanks for your work on this interesting project, thank you also for adding selectable TX periods. I am very happy to test. For those
                            Message 13 of 25 , Mar 26, 2013
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                              Good Morning Guido / All

                              Thanks for your work on this interesting project, thank you also for adding selectable TX periods.
                              I am very happy to test.

                              For those who like me haven't done any serious Linux for a while, installing the new version is merely a case of deleting the WSprryPi folder and re installing from github.

                              To power the RasPi for Radio use, I have in mind a large 5Volt regulator running from my shack 12Volt float charged battery supply, I avoid all mains borne noise in this way. For the moment I am using a 2Amp Switch mode Mains supply which came with the RasPi.

                              I have tried the new version on 24MHz. There is a bug here, one of the WSPR data units has feelings of grandeur and exhibits an 8Hz shift.

                              28MHz . Was very successful on the previous version, on this version there are no decodes despite all looking OK.

                              10MHz. Was fine previously, on this version there are no decodes.

                              7MHz . Decodes fine on both versions.

                              73 Eddie G3ZJO


                              On 26/03/2013 10:20, Guido wrote:  
                              Good morning Eddie, et al,

                              Thanks all for your interest in this project and performing these tests.
                              A good USB power supply is required to prevent 100 Hz side bands. 
                              Most probably this 100Hz created in the rectification stage of your USB 
                              power supply and then mixed with the clock signal on GPIO4. I am 
                              interested to know you measurement results when using another regulated 
                              power supply.

                              The PLL fractional divider stage in the RPi and the alternation algorithm in 
                              WsprryPi are other potential sources of spurs. I found that increasing the 
                              clock of modulating the fractional divider reduces the number of spurs, 
                              especially on higher frequencies (30MHz and up); but unfortunately it also 
                              decrease the frequency resolution making below the required WSPR 
                              symbol bandwidth. If you like to measure spuri, please try my new version 
                              If you change n_iter value in code and re-compile, you may try 50 and 70Mhz, 
                              it is currently blocked.

                              The new version has also a feature that lets you control the duty cycle of 
                              your TX; a set of frequencies can be added where 0 frequency stands for
                              a two minute interval where TX is disabled. E.g 25% duty cycle:

                                    sudo ./wspr G3ZJO FN20 10 7040074 0 0 0

                              73, Guido
                              PE1NNZ

                            • Guido
                              Good afternoon Eddie, Thanks again for performing these tests, very helpful. OK, I understand that the higher clock rates now causing symbols not being aligned
                              Message 14 of 25 , Mar 26, 2013
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                                Good afternoon Eddie,

                                Thanks again for performing these tests, very helpful. 
                                OK, I understand that the higher clock rates now causing symbols not being aligned properly due to rounding errors, need to fix this when have time.
                                For now I have reverted to previous clock rate which should work fine again as before.

                                73, Guido
                                PE1NNZ


                                On Tue, Mar 26, 2013 at 1:54 PM, psk31 <psk31@...> wrote:
                                Good Morning Guido / All

                                Thanks for your work on this interesting project, thank you also for adding selectable TX periods.
                                I am very happy to test.

                                For those who like me haven't done any serious Linux for a while, installing the new version is merely a case of deleting the WSprryPi folder and re installing from github.

                                To power the RasPi for Radio use, I have in mind a large 5Volt regulator running from my shack 12Volt float charged battery supply, I avoid all mains borne noise in this way. For the moment I am using a 2Amp Switch mode Mains supply which came with the RasPi.

                                I have tried the new version on 24MHz. There is a bug here, one of the WSPR data units has feelings of grandeur and exhibits an 8Hz shift.

                                28MHz . Was very successful on the previous version, on this version there are no decodes despite all looking OK.

                                10MHz. Was fine previously, on this version there are no decodes.

                                7MHz . Decodes fine on both versions.

                                73 Eddie G3ZJO



                                On 26/03/2013 10:20, Guido wrote:
                                 
                                Good morning Eddie, et al,

                                Thanks all for your interest in this project and performing these tests.
                                A good USB power supply is required to prevent 100 Hz side bands. 
                                Most probably this 100Hz created in the rectification stage of your USB 
                                power supply and then mixed with the clock signal on GPIO4. I am 
                                interested to know you measurement results when using another regulated 
                                power supply.

                                The PLL fractional divider stage in the RPi and the alternation algorithm in 
                                WsprryPi are other potential sources of spurs. I found that increasing the 
                                clock of modulating the fractional divider reduces the number of spurs, 
                                especially on higher frequencies (30MHz and up); but unfortunately it also 
                                decrease the frequency resolution making below the required WSPR 
                                symbol bandwidth. If you like to measure spuri, please try my new version 
                                If you change n_iter value in code and re-compile, you may try 50 and 70Mhz, 
                                it is currently blocked.

                                The new version has also a feature that lets you control the duty cycle of 
                                your TX; a set of frequencies can be added where 0 frequency stands for
                                a two minute interval where TX is disabled. E.g 25% duty cycle:

                                      sudo ./wspr G3ZJO FN20 10 7040074 0 0 0

                                73, Guido
                                PE1NNZ


                              • Rick Simpson
                                You guys discussing using the Pi as an RF transmitter intrigue me. Can you point me to a site that discusses how the Pi can generate and control frequencies
                                Message 15 of 25 , Mar 26, 2013
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                                  You guys discussing using the Pi as an RF transmitter intrigue me. Can you point me to a site that discusses how the Pi can generate and control frequencies way above its clock rate?
                                   
                                  Rick
                                  K3IND
                                   
                                   
                                  ----- Original Message -----
                                  From: Guido
                                  Sent: Tuesday, March 26, 2013 10:38 AM
                                  Subject: Re: [Raspberry_Pi_4-Ham_RADIO] Raspberry Pi as WSPR transmitter up to 250Mhz

                                   

                                  Good afternoon Eddie,

                                  Thanks again for performing these tests, very helpful. 
                                  OK, I understand that the higher clock rates now causing symbols not being aligned properly due to rounding errors, need to fix this when have time.
                                  For now I have reverted to previous clock rate which should work fine again as before.

                                  73, Guido
                                  PE1NNZ


                                  On Tue, Mar 26, 2013 at 1:54 PM, psk31 <psk31@...> wrote:
                                  Good Morning Guido / All

                                  Thanks for your work on this interesting project, thank you also for adding selectable TX periods.
                                  I am very happy to test.

                                  For those who like me haven't done any serious Linux for a while, installing the new version is merely a case of deleting the WSprryPi folder and re installing from github.

                                  To power the RasPi for Radio use, I have in mind a large 5Volt regulator running from my shack 12Volt float charged battery supply, I avoid all mains borne noise in this way. For the moment I am using a 2Amp Switch mode Mains supply which came with the RasPi.

                                  I have tried the new version on 24MHz. There is a bug here, one of the WSPR data units has feelings of grandeur and exhibits an 8Hz shift.

                                  28MHz . Was very successful on the previous version, on this version there are no decodes despite all looking OK.

                                  10MHz. Was fine previously, on this version there are no decodes.

                                  7MHz . Decodes fine on both versions.

                                  73 Eddie G3ZJO



                                  On 26/03/2013 10:20, Guido wrote:
                                   
                                  Good morning Eddie, et al,

                                  Thanks all for your interest in this project and performing these tests.
                                  A good USB power supply is required to prevent 100 Hz side bands. 
                                  Most probably this 100Hz created in the rectification stage of your USB 
                                  power supply and then mixed with the clock signal on GPIO4. I am 
                                  interested to know you measurement results when using another regulated 
                                  power supply.

                                  The PLL fractional divider stage in the RPi and the alternation algorithm in 
                                  WsprryPi are other potential sources of spurs. I found that increasing the 
                                  clock of modulating the fractional divider reduces the number of spurs, 
                                  especially on higher frequencies (30MHz and up); but unfortunately it also 
                                  decrease the frequency resolution making below the required WSPR 
                                  symbol bandwidth. If you like to measure spuri, please try my new version 
                                  If you change n_iter value in code and re-compile, you may try 50 and 70Mhz, 
                                  it is currently blocked.

                                  The new version has also a feature that lets you control the duty cycle of 
                                  your TX; a set of frequencies can be added where 0 frequency stands for
                                  a two minute interval where TX is disabled. E.g 25% duty cycle:

                                        sudo ./wspr G3ZJO FN20 10 7040074 0 0 0

                                  73, Guido
                                  PE1NNZ


                                • Daniel Ankers
                                  ... Hi Rick, The Pi has a PLL and fractional divider combo built into it which is intended to be used as a general purpose clock. The PLL runs at 2GHz and is
                                  Message 16 of 25 , Mar 27, 2013
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                                    On 26 March 2013 15:49, Rick Simpson <goatguy101@...> wrote:
                                     

                                    You guys discussing using the Pi as an RF transmitter intrigue me. Can you point me to a site that discusses how the Pi can generate and control frequencies way above its clock rate?
                                     
                                    Rick
                                    K3IND


                                    Hi Rick,

                                    The Pi has a PLL and fractional divider combo built into it which is intended to be used as a general purpose clock.  The PLL runs at 2GHz and is then divided by 4 before being fed into the programmable divider - one of the designers states this here: http://raspberrypi.org/phpBB3/viewtopic.php?f=37&t=25301&p=234081#p234081

                                    Regards,
                                    Dan MD1CLV
                                  • Ron Wright
                                    I would be reluctant to use a computer clock for an RF source, that is for any distance. Often lots of work goes into a computer design to reduce the
                                    Message 17 of 25 , Mar 27, 2013
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                                      I would be reluctant to use a computer clock for an RF source, that is for any distance.  Often lots of work goes into a computer design to reduce the radiation to meet FCC part 15 to prevent interference to other devices. Good shielded connectors and good PC board layout with good ground is used.   Us Hams have seen what some computers do to our shack rigs, hi.  Plasma TVs have been known to radiate lots of bad energy, a display problem.

                                      The main reason I would be cautious in using a computer clock or software generated source is computers deal with square waves, or near square.  These are rich in harmonics and something one does not want being radiated.  However, there are applications for such like a signal source for test bench servicing, but for communications not sure how one could make a clean source without good filters.

                                      73, ron, n9ee/r

                                      Ron Wright, N9EE/R
                                      BSEE
                                      Micro Computer Concepts
                                      352-683-4476
                                      mccrpt@...



                                      To: Raspberry_Pi_4-Ham_RADIO@yahoogroups.com
                                      From: md1clv@...
                                      Date: Wed, 27 Mar 2013 11:08:16 +0000
                                      Subject: Re: [Raspberry_Pi_4-Ham_RADIO] Raspberry Pi as WSPR transmitter up to 250Mhz

                                       
                                      On 26 March 2013 15:49, Rick Simpson <goatguy101@...> wrote:

                                       

                                      You guys discussing using the Pi as an RF transmitter intrigue me. Can you point me to a site that discusses how the Pi can generate and control frequencies way above its clock rate?
                                       
                                      Rick
                                      K3IND


                                      Hi Rick,

                                      The Pi has a PLL and fractional divider combo built into it which is intended to be used as a general purpose clock.  The PLL runs at 2GHz and is then divided by 4 before being fed into the programmable divider - one of the designers states this here: http://raspberrypi.org/phpBB3/viewtopic.php?f=37&t=25301&p=234081#p234081

                                      Regards,
                                      Dan MD1CLV

                                    • psk31
                                      ... Hi Dan, plus All When thanking Guido yesterday for his work on the WsprryPi project, I neglected to include your work, I did mean to but unfortunately
                                      Message 18 of 25 , Mar 27, 2013
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                                        On 27/03/2013 11:08, Daniel Ankers wrote:
                                        The Pi has a PLL and fractional divider combo built into it which is intended to be used as a general purpose clock.  The PLL runs at 2GHz and is then divided by 4 before being fed into the programmable divider - one of the designers states this here: http://raspberrypi.org/phpBB3/viewtopic.php?f=37&t=25301&p=234081#p234081

                                        Regards,
                                        Dan MD1CLV
                                        Hi Dan, plus All

                                        When thanking Guido yesterday for his work on the WsprryPi project, I neglected to include your work, I did mean to but unfortunately often my thoughts get lost somewhere. I haven't yet tried your version, I do intend to.

                                        WsprryPi Power Supply Tests

                                        Today I have concentrated my efforts on the Power Supply for the RaspPi to see how much improvement there is in the 'hum' sidebands if a clean supply is used.

                                        I used a 5 Volt Regulator with  the usual input and output capacitors connected to my 13.8Volt float charged battery shack supply, powering the RaspPi via the mini USB socket. The reduction in  sidebands was clear, however the keyboard went wild inputting strings of random characters. Now where have I heard of this before, reports of "when I used the RasPi with a powered hub made by X, I got random keyboard operation".
                                        Connecting to my shack supply connects to my Antenna Earth, something which will be necessary if and when the Wsprry goes on air. Normally everything on the Pi floats and they get away with it, maybe bonding the supply negative to earth changes the characteristics for pickup of mains supply noise.
                                        Next I tried a 12Volt gel battery as the power source, same wiring but now floating above earth, the keyboard worked fine, 100Hz sidebands were down measuring -21dB on 7MHz.

                                        So with a clean supply to the RasPi it was still producing what looked like mains related, modulated sidebands. Once WsprrPi was running
                                        I switched off the USB powered hub, the sidebands vanished below detectable levels on 7MHz. Most likely the rubbish from the Switching Regulator was also causing the keyboard problem when the set up was earthed.

                                        Solution, my original thought. Powering everything from the shack supply. I used a large heatsink with 2 mounting places for the original 5Volt regulator. I added another regulator with the usual capacitors and  for good luck decoupled the separate outputs which feed two USB sockets with a 1000pF and 1000uF each. The powered hub now receives its power via a USB lead.

                                        Conclusion, to use the RasPi as a DDS / QRP transmitter it is essential that a clean power supply system is used, for the computer and peripherals too,  not surprising really.

                                        73
                                        Eddie G3ZJO



                                         
                                      • psk31
                                        ... Hi Guido / Group Following today s PSU building work there are some nice improvements, results so far for LF, MF and HF Bands. Test set up, a very short
                                        Message 19 of 25 , Mar 27, 2013
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                                          On 26/03/2013 10:20, Guido wrote:
                                          I am 
                                          interested to know you measurement results when using another regulated 
                                          power supply.
                                          Hi Guido / Group

                                          Following today's PSU building work there are some nice improvements, results so far for LF, MF and HF Bands.

                                          Test set up, a very short wire on GPIO4 providing 0dB or greater WSPR signal.

                                          136KHz, 474KHz,1.9MHz Spurii below detectable levels on Spectrum Lab using Kenwood TS870 as RX.

                                          3.6MHz, visible sidebands but below WSPR decode level.
                                           
                                          7MHz, 100Hz sidebands -27dB.

                                          10MHz, Sidebands below decode levels.

                                          14MHz, 100Hz sidebands -25dB

                                          17MHz, 21MHz, Sidebands below decode levels.

                                          24MHz, 28MHz, Both frequencies have a close in companion WSPR modulated product, HF of the wanted signal, 100Hz WSPR modulated sidebands and a comb of spurs. I really wouldn't want to transmit this even as a QRP test transmission.

                                          Tomorrow I might get round to connecting some LPF's and maybe getting some reports.

                                          73 Eddie G3ZJO

                                        • Robert Nickels
                                          ... I ll chime in on the benefits of using a real power supply. Check hamfest under the table boxes for 5 volt open frame power supplies - they used to be
                                          Message 20 of 25 , Mar 28, 2013
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                                            On 3/27/2013 4:16 PM, psk31 wrote:
                                            > measurement results when using another regulated
                                            > power supply.

                                            I'll chime in on the benefits of using a real power supply. Check
                                            hamfest "under the table boxes" for 5 volt open frame power supplies -
                                            they used to be free or nearly so but aren't as common nowadays. I'm
                                            using a 3A 5V Power One that feeds into the GPIO connector and have a
                                            noticeably reduced noise level when using the Pi as an SDR dongle server
                                            with my HF converter. I haven't tried to measure it but it was like
                                            flipping off a switch. For ham apps running on the Pi at home, I can't
                                            see any downslide to using a good regulated DC supply and preferably a
                                            linear rather than switcher.

                                            73, Bob W9RAN
                                          • psk31
                                            ... Sure thing Bob I had very good results today, although I didn t check all bands, with an old, typical CB type 3A linear PSU to feed my 5Volt USB set up. I
                                            Message 21 of 25 , Mar 28, 2013
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                                              On 28/03/2013 16:09, Robert Nickels wrote:
                                              > For ham apps running on the Pi at home, I can't
                                              > see any downslide to using a good regulated DC supply and preferably a
                                              > linear rather than switcher.
                                              Sure thing Bob I had very good results today, although I didn't check
                                              all bands, with an old, typical CB type 3A linear PSU to feed my 5Volt
                                              USB set up.

                                              I found a couple of my QRP Low Pass Filters one for 14MHz and one for
                                              7MHz. So that set the bands to test on air at this time.

                                              Had an hour or so on 14MHz, with no reports so changed to 7MHz.

                                              However just after I changed to 7MHz I found this report on the Data
                                              Base, my first report with the Pi sneaked in at the last moment.

                                              2013-03-28 16:22 G3ZJO 14.097119 -23 1 IO92ng
                                              +7 0.005 LY2BOS KO24or 1736 1079

                                              Now on 7Mhz the Spots are coming in from all around Europe.

                                              2013-03-28 17:40 G3ZJO 7.040083 -15 1 IO92ng
                                              +7 0.005 PI4THT JO32kf 527 327
                                              2013-03-28 17:36 G3ZJO 7.040084 -20 1 IO92ng
                                              +7 0.005 DK6UG JN49cm 706 439
                                              2013-03-28 17:36 G3ZJO 7.040099 -16 0 IO92ng
                                              +7 0.005 ON7KO JO21ce 370 230
                                              2013-03-28 17:36 G3ZJO 7.040081 -19 0 IO92ng
                                              +7 0.005 OZ7IT JO65df 924 574
                                              2013-03-28 17:32 G3ZJO 7.040066 -18 0 IO92ng
                                              +7 0.005 PA7EY JO22jj 385 239
                                              2013-03-28 17:32 G3ZJO 7.040093 -18 0 IO92ng
                                              +7 0.005 F4CWN/2 JN03kn 977 607
                                              2013-03-28 17:32 G3ZJO 7.040088 -20 1 IO92ng
                                              +7 0.005 EI9GNB IO51sv 520 323
                                              2013-03-28 17:32 G3ZJO 7.040081 -17 0 IO92ng
                                              +7 0.005 OZ7IT JO65df 924 574
                                              2013-03-28 17:32 G3ZJO 7.040084 -21 0 IO92ng
                                              +7 0.005 DK6UG JN49cm 706 439
                                              2013-03-28 17:32 G3ZJO 7.040082 -16 0 IO92ng
                                              +7 0.005 PI4THT JO32kf 527 327
                                              2013-03-28 17:32 G3ZJO 7.040098 -24 1 IO92ng
                                              +7 0.005 ON7KO JO21ce 370 230
                                              2013-03-28 17:28 G3ZJO 7.040088 -21 1 IO92ng
                                              +7 0.005 EI9GNB IO51sv 520 323
                                              2013-03-28 17:28 G3ZJO 7.040082 -21 0 IO92ng
                                              +7 0.005 F1JRD/3 JN03on 981 610
                                              2013-03-28 17:28 G3ZJO 7.040067 -17 0 IO92ng
                                              +7 0.005 PA7EY JO22jj 385 239
                                              2013-03-28 17:28 G3ZJO 7.040084 -20 1 IO92ng
                                              +7 0.005 DK6UG JN49cm 706 439
                                              2013-03-28 17:28 G3ZJO 7.040083 -16 1 IO92ng
                                              +7 0.005 PI4THT JO32kf 527 327
                                              2013-03-28 17:20 G3ZJO 7.040080 -27 0 IO92ng
                                              +7 0.005 IK1WVQ JN44cb 1133 704
                                              2013-03-28 17:20 G3ZJO 7.040081 -15 0 IO92ng
                                              +7 0.005 OZ7IT JO65df 924 574
                                              2013-03-28 17:20 G3ZJO 7.040088 -21 0 IO92ng
                                              +7 0.005 EI9GNB IO51sv 520 323
                                              2013-03-28 17:20 G3ZJO 7.040067 -16 1 IO92ng
                                              +7 0.005 PA7EY JO22jj 385 239
                                              2013-03-28 17:20 G3ZJO 7.040099 -19 1 IO92ng
                                              +7 0.005 ON7KO JO21ce 370 230
                                              2013-03-28 17:20 G3ZJO 7.040083 -17 0 IO92ng
                                              +7 0.005 PI4THT JO32kf 527 327
                                              2013-03-28 17:16 G3ZJO 7.040067 -17 1 IO92ng
                                              +7 0.005 PA7EY JO22jj 385 239
                                              2013-03-28 17:16 G3ZJO 7.040083 -18 0 IO92ng
                                              +7 0.005 PI4THT JO32kf 527 327
                                              2013-03-28 17:12 G3ZJO 7.040083 -18 0 IO92ng
                                              +7 0.005 PI4THT JO32kf 527 327
                                              2013-03-28 17:12 G3ZJO 7.040067 -19 0 IO92ng
                                              +7 0.005 PA7EY JO22jj 385 239

                                              No surprises there, I am a keen QRP'er but pretty impressive that the Pi
                                              is doing everything. I must set the power correct I measure about 15mW,
                                              5mW is just an old habit of mine.

                                              73 Eddie G3ZJO
                                            • Robert Nickels
                                              ... Not for an experienced guy like you Eddie, but I m in awe! I m off to make LPF - would appreciate any suggestion as to which band(s) are best -
                                              Message 22 of 25 , Mar 28, 2013
                                              • 0 Attachment
                                                On 3/28/2013 12:51 PM, psk31 wrote:
                                                > No surprises there,

                                                Not for an experienced guy like you Eddie, but I'm in awe! I'm off
                                                to make LPF - would appreciate any suggestion as to which band(s) are
                                                best - otherwise I'll probably try 20 meters. Will be my first
                                                go-round with WSPR.

                                                Nice work, all!

                                                73, Bob W9RAN
                                              • Guido
                                                There is an update of WsprryPi, now supporting some new features that was requested by few: 1. the slower brother of WSPR-2 is supported called WSPR-15. To use
                                                Message 23 of 25 , Apr 1, 2013
                                                • 0 Attachment
                                                  There is an update of WsprryPi, now supporting some new features that was requested by few:

                                                  1. the slower brother of WSPR-2 is supported called WSPR-15. To use it, specify a frequency in the 25Hz sub-band that is just above the regular wspr band:
                                                       LF   137400 - 137600
                                                            137600 - 137625 (WSPR-15)
                                                       MF   475600 - 475800
                                                            475800 - 475825 (WSPR-15)
                                                      160m  1838000 - 1838200
                                                            1838200 - 1838225 (WSPR-15)

                                                  2. it is now possible to specify either a prefix or suffix in the callsign.
                                                  Prefix may contain up to three characters before the callsign, e.g: EA8/PE1NNZ or F/PE1NNZ.
                                                  Suffixes may contain a single alphanumeric character or double digit, e.g: PE1NNZ/p, PE1NNZ/1, PE1NNZ/99

                                                  New features can be downloaded in github: https://github.com/threeme3/WsprryPi.git

                                                  73, Guido
                                                  PE1NNZ


                                                  On Fri, Mar 29, 2013 at 2:55 AM, Robert Nickels <w9ran@...> wrote:
                                                  On 3/28/2013 12:51 PM, psk31 wrote:
                                                  > No surprises there,

                                                  Not for an experienced guy like you Eddie, but I'm in awe!     I'm off
                                                  to make LPF - would appreciate any suggestion as to which band(s) are
                                                  best - otherwise I'll probably try 20 meters.   Will be my first
                                                  go-round with WSPR.

                                                  Nice work, all!

                                                  73, Bob W9RAN


                                                  ------------------------------------

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                                                • Jon Ove Johnsen
                                                  Hi Guido, Thanks for the last versions of WsprryPi. There are of course always more to wish for. The communication between us has not been perfect. I will
                                                  Message 24 of 25 , Apr 5, 2013
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                                                    Hi Guido,
                                                    Thanks for the last versions of WsprryPi.
                                                    There are of course always more to wish for.
                                                    The communication between us has not been perfect.
                                                    I will try to summarize my comments.

                                                    1. Calibration.
                                                    I would like to suggest that the calibration should always be done for a particular RasPi board before any txing is performed.
                                                    The calibrating could be done in a few steps by the command wspr LA3JJ JO59 10 10140200 C  offset, where offset  may be + or - 1, 10 ,100 . This because to use the editor vi and a new compilation is a bit complicated. When a board has been calibrated it has been so for life, so the value should be saved in a file in the home dir and be automatically used the next time when a new version is loaded.

                                                    2. Hash coding.
                                                    To be able to run txing of longer messages hash coding concept has been used. In my Arduino applications I have still not implemented this, but instead used the program from W3PM to generate the two messages on my W7 PC. When I in advance know the location I have made sets of the relevant dual symbol codes hard coded and select-able from my Arduino LCD screen. The hash coding seemed a bit over my head. At W3PM's pages there are examples of this, but so far I will not go into this for my part. (It would have been nice to have it implemented though as my Arduino is interfaced to a GPS module and calculates the Maidenhead location continuously.)

                                                    3. Time sync.
                                                    The WsprrPi uses time sync via the internet. It would have been nice to have sync from a GPS module also to be able to run it really portable.
                                                    point a) here is to read and decode GPS time from a GPS module like I have done in my Arduino. Or pint b) to have an input pin (or two) on the RasPi where GPS generated minute time pulses could be received.

                                                    4. Multiple band operation.
                                                    I made a comment of this:   http://wsprnet.org/drupal/node/3994#comment-9882

                                                     At the moment I am visiting family at loc JP54 and as my present WsprryPi needs wired internet connection I decided not to bring it along.
                                                    I do hope I will be able to make it a fully portable rig in the future.
                                                    At the age of 70 now I am learning a little more about C and Python coding every day, but it moves on very slowly.

                                                    73
                                                    Jon Ove, la3jj

                                                    .

                                                    Fra: Guido <threeme3@...>
                                                    Til: Raspberry_Pi_4-Ham_RADIO@yahoogroups.com
                                                    Sendt: Mandag, 1. april 2013 20.04
                                                    Emne: Re: [Raspberry_Pi_4-Ham_RADIO] Raspberry Pi as WSPR transmitter up to 250Mhz

                                                     
                                                    There is an update of WsprryPi, now supporting some new features that was requested by few:

                                                    1. the slower brother of WSPR-2 is supported called WSPR-15. To use it, specify a frequency in the 25Hz sub-band that is just above the regular wspr band:
                                                         LF   137400 - 137600
                                                              137600 - 137625 (WSPR-15)
                                                         MF   475600 - 475800
                                                              475800 - 475825 (WSPR-15)
                                                        160m  1838000 - 1838200
                                                              1838200 - 1838225 (WSPR-15)

                                                    2. it is now possible to specify either a prefix or suffix in the callsign.
                                                    Prefix may contain up to three characters before the callsign, e.g: EA8/PE1NNZ or F/PE1NNZ.
                                                    Suffixes may contain a single alphanumeric character or double digit, e.g: PE1NNZ/p, PE1NNZ/1, PE1NNZ/99

                                                    New features can be downloaded in github: https://github.com/threeme3/WsprryPi.git

                                                    73, Guido
                                                    PE1NNZ


                                                    On Fri, Mar 29, 2013 at 2:55 AM, Robert Nickels <w9ran@...> wrote:
                                                    On 3/28/2013 12:51 PM, psk31 wrote:
                                                    > No surprises there,

                                                    Not for an experienced guy like you Eddie, but I'm in awe!     I'm off
                                                    to make LPF - would appreciate any suggestion as to which band(s) are
                                                    best - otherwise I'll probably try 20 meters.   Will be my first
                                                    go-round with WSPR.

                                                    Nice work, all!

                                                    73, Bob W9RAN


                                                    ------------------------------------

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                                                  • ferrymanr
                                                    I wonder if anyone has looked into using the RPi as a DDS synthyesiser. I would guess it might be possible to create up to 25MHz but not sure whether it is
                                                    Message 25 of 25 , Apr 5, 2013
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                                                      I wonder if anyone has looked into using the RPi as a DDS synthyesiser. I would guess it might be possible to create up to 25MHz but not sure whether it is practically possible.
                                                      Dick G4BBH
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