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Re: [Raspberry_Pi_4-Ham_RADIO] Pi as a "dongle server" for SDR

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  • Robert Nickels
    ... Hi Rick, Yes, my own copy just arrived yesterday, but due to space limitations I wasn t able to mention the dongle server concept (plus it would have
    Message 1 of 20 , Dec 15, 2012
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      On 12/14/2012 9:27 PM, Rick Simpson wrote:
      > Is it correct that the Pi simply acts to convert the IQ signals from
      > the USB stick to the local area network consisting of one or more PCs?
      > Does the Pi do any other processing of the IQ signals? I guess I
      > should just wait for the new issue of QST.

      Hi Rick,

      Yes, my own copy just arrived yesterday, but due to space limitations I
      wasn't able to mention the "dongle server" concept (plus it would have
      probably been beyond the technical scope they are after). But your
      description is correct - this approach makes the SDR into a
      client/server app. The dongle attaches to the R-Pi and runs Osmocom's
      "rtl_tcp" app, which provides a command interface via TCP to tune and
      control the dongle parameters, and which packages the I/Q samples into
      TCP packets. On the SDR (client) side (I use SDR# exclusively so
      that's the only DSP app I can really comment on) - you select "rtl-tcp"
      as the "front end" and specify the IP address of the R-Pi on your
      network, and that's all there is to it. The tuning is usually just as
      responsive as a direct USB connection, and the neat thing is you can now
      go to any PC on your LAN and run SDR# and it will work just as if the
      dongle was attached to that PC. Of course, only one user can be in
      control at a time (although there's probably a way to do multi-user
      control, which would be pretty neat in a school, for example). There
      could be any number of remote dongle servers, linked via the internet to
      do all sorts of interesting things!

      A different SDR app (ghpsdr3) is based on a three-tiered client/server
      architecture (rather than just two). The first is a "radio server"
      similar to the above, but the DSP task is divided intoa "dsp server" and
      a "GUI". This dsp server must run on a PC that has the necessary
      processing power, but there are GUI clients for Android, iOS, WIndows,
      Linux, etc. To be able to send the GUI over a network, the dsp
      server creates a "low bandwidth version of the spectrum in 8 bit data,
      the audio data 8-bit ALAW audio format at only 480 sample size at 10
      times a second." You can find demos on Youtube that are really cool,
      and I like this approach myself as it would make it possible to use
      inexpensive tablets as your "walkie/talkie/lookie" SDR interface!
      Also in this architecture, one Pi could act as the radio server and
      another as the GUI, (assuming a suitable GUI client app existed - the
      current jmonitor client is written in Java).

      I just haven't had time to personally play with ghpsdr3 (or the "alex"
      version) - but according to their wiki page, it supports " HPSDR,
      Softrock, UHFSDR, Microtelecom Perseus, SDR-iq, HiQSDR, Ettus Research
      USRP and rtl-sdr DVB-T dongles".

      Without doubt, the SDR world is rapidly evolving so if you don't like
      today's offerings, check back tomorrow! As they say, "it only takes
      software".

      73, Bob W9RAN
    • Mathison Ott
      Hi ALL, This has been done in the ghpsdr3 project. Here is my site with whaty ive done with sdr s, previously. http://qsl.net/kj6dzb/HAM/sdr%20makin.html
      Message 2 of 20 , Dec 15, 2012
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         Hi ALL,
         
        This has been done in the ghpsdr3 project. Here is my site with whaty ive done with sdr's, previously. 
         
         
         
        There is a problem/do with project:....
        1. At the moment the project hasnt tacked a a server that that can make conections from multible hardware servers (ie no mixing softrocks and HPSDR servers, on 1 server.
        2. I have a some modified code for the RTL-server  hat will decetct multible rtl devises, but the code in the DSP server can take advantage of having 2 recevers. 
         
        Project Goals

        1. Open source (GPL) SDR software

        2. Client-server network-enabled by design from the ground up

        3. Customized server for each SDR hardware type. Currently supporting HPSDR, Softrock, UHFSDR, Microtelecom Perseus, RFSPACE SDR-IQ, HiQSDR, Ettus Research USRP, and the rtl-sdr DVB-T dongle.

        4. Single dspserver that connects to single server. However, each server can have multiple Rx and Tx channels.

        5. Multiple clients, such as QtRadio, that can concurrently connect to a single dspserver.

        6. Full Rx and Tx capability for hardware capable of Tx

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

         
        Im working on a multi band SDR server. So i biult a enclosure with a softrock2 & 2 RTLSDR. It all runs on 120v--12v power and a USB port. This brings me to my next point. The SDR-wiget group has goten a few RPi up and running with the software, with mixed performance results results. I my self have never been able to get my two RPi and rtlsdrs in the same lab together. I should soon.

        73 KJ6DZB
         
      • Robert Nickels
        ... Hi Siegfried, Yes, in theory - but I ve not got any hardware or software going yet. Hopefully we ll find someone smarter at linux than I am who can help
        Message 3 of 20 , Dec 15, 2012
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          On 12/15/2012 10:43 AM, siegfried jackstien wrote:
          >
          > Do you know how to remotely control the gpio pins??
          >
          Hi Siegfried,

          Yes, in theory - but I've not got any hardware or software going yet.
          Hopefully we'll find someone smarter at linux than I am who can help
          with a simple app to toggle a few bits on/off so we can start to do
          things like you've described.
          >
          >
          > I am asking cause I wanna build a "filtered" preamp board (maybe with
          > also a
          > shortwave converter) ... and for that I have to have a few pins selectable
          > (to change filters and other things)
          >

          A good idea. I was after the simplest and cheapest approach that would
          provide acceptable performance for entry-level newbies. For example,
          I'd love to see these things in classrooms to show kids what's really
          out in the RF world we all take for granted nowadays. So that led me to
          a minimalist design, but everything you describe is certainly doable and
          "right" in terms of optimizing performance.
          >
          >
          > The e4k is a bit deaf ... and a receiver with an iput as big as a barn
          > door
          > .... so a low noise preamp (with high ip3 that is is not overloaded
          > even on
          > strong signals) ... and then switched filters behind it ...
          >
          Well I'm a bit skeptical - the tuned LNA in the E4000 has really
          impressed me. As an example, I'm hearing ADS-B "virtual radar" signals
          from planes 100 miles away with no other LNA and just a collinear
          vertical fed via 50 ft. of RG/GU. There's probably room for
          improvement with a good preamp and filters, but it's pretty good as-is
          IMHO for lots of uses.

          You (and others) might be interested in the white papers from Elonics
          (before they went out of business) that describe the "Digital Tune
          Architecture" of the e4K chip - you can find them at goo.gl/suS2w
          <http://goo.gl/suS2w> But from all indications, the Raphael R820T tuner
          that is also supported works quite well too.

          73, Bob W9RAN
        • Rick Simpson
          Complete info on manipulating the I/O pins is in the Raspberry Pi User Guide by Upton and Halfacree available from Amazon. It has complete Python code for
          Message 4 of 20 , Dec 15, 2012
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            Complete info on manipulating the I/O pins is in the "Raspberry Pi User Guide" by Upton and Halfacree available from Amazon. It has complete Python code for what you want to do. I would also check the back issues of the Magpi, the free online RPi magazine.
             
            Rick
            ----- Original Message -----
            Sent: Saturday, December 15, 2012 1:18 PM
            Subject: Re: AW: [Raspberry_Pi_4-Ham_RADIO] Pi as a "dongle server" for SDR

             

            On 12/15/2012 10:43 AM, siegfried jackstien wrote:
            >
            > Do you know how to remotely control the gpio pins??
            >
            Hi Siegfried,

            Yes, in theory - but I've not got any hardware or software going yet.
            Hopefully we'll find someone smarter at linux than I am who can help
            with a simple app to toggle a few bits on/off so we can start to do
            things like you've described.
            >
            >
            > I am asking cause I wanna build a "filtered" preamp board (maybe with
            > also a
            > shortwave converter) ... and for that I have to have a few pins selectable
            > (to change filters and other things)
            >

            A good idea. I was after the simplest and cheapest approach that would
            provide acceptable performance for entry-level newbies. For example,
            I'd love to see these things in classrooms to show kids what's really
            out in the RF world we all take for granted nowadays. So that led me to
            a minimalist design, but everything you describe is certainly doable and
            "right" in terms of optimizing performance.
            >
            >
            > The e4k is a bit deaf ... and a receiver with an iput as big as a barn
            > door
            > .... so a low noise preamp (with high ip3 that is is not overloaded
            > even on
            > strong signals) ... and then switched filters behind it ...
            >
            Well I'm a bit skeptical - the tuned LNA in the E4000 has really
            impressed me. As an example, I'm hearing ADS-B "virtual radar" signals
            from planes 100 miles away with no other LNA and just a collinear
            vertical fed via 50 ft. of RG/GU. There's probably room for
            improvement with a good preamp and filters, but it's pretty good as-is
            IMHO for lots of uses.

            You (and others) might be interested in the white papers from Elonics
            (before they went out of business) that describe the "Digital Tune
            Architecture" of the e4K chip - you can find them at goo.gl/suS2w
            <http://goo.gl/suS2w> But from all indications, the Raphael R820T tuner
            that is also supported works quite well too.

            73, Bob W9RAN

          • David Kjellquist
            Remote control of the GPIO pins can be accomplished several ways. 1. Python socket programming with a simple client program communicating with a server on RPi.
            Message 5 of 20 , Dec 15, 2012
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              Remote control of the GPIO pins can be accomplished several ways.

              1. Python socket programming with a simple client program communicating with a server on RPi. The server, also in Python, uses the RPi.GPIO module. Adafruit has several tutorials using python and RPi.GPIO  Socket programming isn't too difficult.
              2. Check out webiopi that provides a REST framework(  http://code.google.com/p/webiopi/ ) With a REST frame work you can either use a Python client executing POST/ GET commands with Python requests module. Or, via a simple web browser - javascript enabled web page. Both methods connect to webiopi running on Raspberry Pi.

              Python is good because it's available for almost any computing platform.

              I am in the process of completing a RPi wireless (WiFi) or wired (Ethernet) 1x6 100 watt antenna switch that will use any of these methods.

              Software and proto board hardware are working. Assembly of a finished switch will start after the holidays. I plan on submitting to QST.

              Dave,  WB5NHL




              On 12/15/2012 1:18 PM, Robert Nickels wrote:
               

              On 12/15/2012 10:43 AM, siegfried jackstien wrote:
              >
              > Do you know how to remotely control the gpio pins??
              >
              Hi Siegfried,

              Yes, in theory - but I've not got any hardware or software going yet.
              Hopefully we'll find someone smarter at linux than I am who can help
              with a simple app to toggle a few bits on/off so we can start to do
              things like you've described.
              >
              >
              > I am asking cause I wanna build a "filtered" preamp board (maybe with
              > also a
              > shortwave converter) ... and for that I have to have a few pins selectable
              > (to change filters and other things)
              >

              A good idea. I was after the simplest and cheapest approach that would
              provide acceptable performance for entry-level newbies. For example,
              I'd love to see these things in classrooms to show kids what's really
              out in the RF world we all take for granted nowadays. So that led me to
              a minimalist design, but everything you describe is certainly doable and
              "right" in terms of optimizing performance.
              >
              >
              > The e4k is a bit deaf ... and a receiver with an iput as big as a barn
              > door
              > .... so a low noise preamp (with high ip3 that is is not overloaded
              > even on
              > strong signals) ... and then switched filters behind it ...
              >
              Well I'm a bit skeptical - the tuned LNA in the E4000 has really
              impressed me. As an example, I'm hearing ADS-B "virtual radar" signals
              from planes 100 miles away with no other LNA and just a collinear
              vertical fed via 50 ft. of RG/GU. There's probably room for
              improvement with a good preamp and filters, but it's pretty good as-is
              IMHO for lots of uses.

              You (and others) might be interested in the white papers from Elonics
              (before they went out of business) that describe the "Digital Tune
              Architecture" of the e4K chip - you can find them at goo.gl/suS2w
              <http://goo.gl/suS2w> But from all indications, the Raphael R820T tuner
              that is also supported works quite well too.

              73, Bob W9RAN


            • Robert Nickels
              ... Excellent Dave! I ve thought of that to, and look forward to seeing what you come up with. 73, Bob W9RAN
              Message 6 of 20 , Dec 15, 2012
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                On 12/15/2012 1:19 PM, David Kjellquist wrote:
                > I plan on submitting to QST

                Excellent Dave! I've thought of that to, and look forward to seeing
                what you come up with.

                73, Bob W9RAN
              • flask28
                I have used a KPC3+ (in kiss mode) and a TinyTrack4 with my Pi. The TT4 is 30% of the cost of the KPC3+ and it worked great. They both worked great, actually.
                Message 7 of 20 , Dec 15, 2012
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                  I have used a KPC3+ (in kiss mode) and a TinyTrack4 with my Pi. The TT4 is 30% of the cost of the KPC3+ and it worked great. They both worked great, actually.

                  I used the serial port on the Pi's GPIO pins rather than use a usb port.

                  http://m0hpj.wordpress.com/tag/raspberrypi/

                  Something along these lines. I got a $3 TTL to RS232 converter off ebay and it works great.

                  I also worked with soundmodem for about three weeks, I was using a USB Signalink as my radio interface. It worked, for sure. But the packet decode success was 30% of what the hardware TNC's was, listening to APRS for example. I worked on tuning it for better performance for days and days but never really got it close to the TNC in terms of decode performance. Encoding and transmitting seemed to work fine though, and I moved winlink mail using soundmodem, so it at least sorta works.

                  I overclocked the Pi to get fldigi working, and I noticed packet decode with soundmodem improved a ton at 1ghz vs 700mhz (as did fldigi decoding). But my Pi is completely unstable at that speed. The best stable speed this unit likes is 775mhz which didn't that much gain over the stock speeds.

                  I say stick with a hardware TNC, either the TNC-X or the TT4. If you don't have other plans for the serial port on the GPIO header I'd use that over a usb/serial converter just for simplicity, but it seems like lots of guys are having success using converter or a usb TNC-X. So either is fine.

                  Adam
                  KF7LJH

                  --- In Raspberry_Pi_4-Ham_RADIO@yahoogroups.com, Ronny Julian K4RJJ <k4rjj@...> wrote:
                  >
                  > Is this a good idea for a remote site? Stable as a TNC?
                  >
                  > On 12/14/2012 3:22 PM, Mathison Ott wrote:
                  > > Think about using an audio card, and use the I/O pins on the RPi for PTT.
                  > >
                  > > http://www.linux-ax25.org/wiki/Soundmodem
                  > >
                  > > 73
                  > > Mathison kj6dzb
                  > >
                  >
                • Mathison Ott
                  WB5NHL, Keep me posted, i have a few sample switching relays, from the UHFSDR project. I am in the process of completing a RPi wireless (WiFi) or wired
                  Message 8 of 20 , Dec 15, 2012
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                    WB5NHL, Keep me posted, i have a few sample switching relays, from the UHFSDR project.
                     
                    I am in the process of completing a RPi wireless (WiFi) or wired (Ethernet) 1x6 100 watt antenna switch that will use any of these methods.
                     
                    dose your project have a web interface? for comand, it would make running multible switches EZ.
                    ----------------------------
                     
                    Ive been biulding big and small Pan/Tilt heads for a bit now, and with the RPi running Gpredict, code to interface with the USB servo controler would make for a satalite tracking or antenna rotator, A scensor package could add Gyro and magnetic north atharithmic tracking refinment, as well as a s/w r read from an I/O pin.
                     
                     
                     
                    73 Kj6dzb
                    Mathison

                     
                     
                     
                  • K2DMS
                    I wonder if the ArgetData OTUSB can be used with the Pi over USB? It emulates serial connection and has AGC for the receive audio in the latest firmware.
                    Message 9 of 20 , Dec 15, 2012
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                      I wonder if the ArgetData OTUSB can be used with the Pi over USB? It emulates serial connection and has AGC for the receive audio in the latest firmware. Around $40.

                      Danny
                      K2DMS

                      --- In Raspberry_Pi_4-Ham_RADIO@yahoogroups.com, "flask28" <kf7ljh@...> wrote:
                      >
                      > I have used a KPC3+ (in kiss mode) and a TinyTrack4 with my Pi. The TT4 is 30% of the cost of the KPC3+ and it worked great. They both worked great, actually.
                      >
                      > I used the serial port on the Pi's GPIO pins rather than use a usb port.
                      >
                      > http://m0hpj.wordpress.com/tag/raspberrypi/
                      >
                      > Something along these lines. I got a $3 TTL to RS232 converter off ebay and it works great.
                      >
                      > I also worked with soundmodem for about three weeks, I was using a USB Signalink as my radio interface. It worked, for sure. But the packet decode success was 30% of what the hardware TNC's was, listening to APRS for example. I worked on tuning it for better performance for days and days but never really got it close to the TNC in terms of decode performance. Encoding and transmitting seemed to work fine though, and I moved winlink mail using soundmodem, so it at least sorta works.
                      >
                      > I overclocked the Pi to get fldigi working, and I noticed packet decode with soundmodem improved a ton at 1ghz vs 700mhz (as did fldigi decoding). But my Pi is completely unstable at that speed. The best stable speed this unit likes is 775mhz which didn't that much gain over the stock speeds.
                      >
                      > I say stick with a hardware TNC, either the TNC-X or the TT4. If you don't have other plans for the serial port on the GPIO header I'd use that over a usb/serial converter just for simplicity, but it seems like lots of guys are having success using converter or a usb TNC-X. So either is fine.
                      >
                      > Adam
                      > KF7LJH
                      >
                      > --- In Raspberry_Pi_4-Ham_RADIO@yahoogroups.com, Ronny Julian K4RJJ <k4rjj@> wrote:
                      > >
                      > > Is this a good idea for a remote site? Stable as a TNC?
                      > >
                      > > On 12/14/2012 3:22 PM, Mathison Ott wrote:
                      > > > Think about using an audio card, and use the I/O pins on the RPi for PTT.
                      > > >
                      > > > http://www.linux-ax25.org/wiki/Soundmodem
                      > > >
                      > > > 73
                      > > > Mathison kj6dzb
                      > > >
                      > >
                      >
                    • Robert Nickels
                      Just as a follow-up on this, I thought I d pass along some CPU utilization data (per TOP) for using the R-Pi as a dongle server. In other words, this is a Pi
                      Message 10 of 20 , Dec 16, 2012
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                        Just as a follow-up on this, I thought I'd pass along some CPU
                        utilization data (per TOP) for using the R-Pi as a dongle server. In
                        other words, this is a Pi without any X or GUI, running rtl_tcp:

                        1. Sample rate of 1,024,000 samples per second; avg 29%
                        utilization, 5% memory
                        2. Sample rate of 2,048,000 samples per second: avg. 60% CPU
                        utilization, 5% memory

                        This is the burden on the Pi for just taking I/Q data from the USB port
                        and loading it into TCP packets. It would be interesting to know how
                        this compares with a soundcard-based SDR, but it still seems to me we'll
                        need access to the GPU in order to ever put a DSP on the Pi. If it can
                        run Blu Ray video it ought to have the horses needed to run an SDR DSP.

                        73, Bob W9RAN
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