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Re: [linuxham] Fldigi for VHF/UHF FM data [1 Attachment]

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  • Geoff McAlpin
    Here in the Seattle area there is a group that uses MT-63 2000 over 2m FM. They are actually using it over one of the local repeaters. In addition to sending
    Message 1 of 8 , Jul 26, 2013
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      Here in the Seattle area there is a group that uses MT-63 2000 over 2m FM. They are actually using it over one of the local repeaters. In addition to sending direct entry text, they are able to send image and document files as well. I have listened in on a few of their nets and it seems to work very well.

      Geoff, N7PGN
      Seattle, WA
      CN87tr

      On Jul 26, 2013 11:06 AM, "John Phelps" <kl4yfd@...> wrote:
       
      [Attachment(s) from John Phelps included below]

      Hello all,
      Apologies for the number of mailing-lists this touches, but am taking a bit of a survey:

      Want see how many people would be interested in using, developing, and/or testing Fldigi for "high speed" data over FM audio and/or FM-audio repeaters. In my testing so far, it appears the speed would be somewhere in the 3 Kb/s to 4 Kb/s range, possibly higher.

      Since the goal is fast data, audio coupling is out: faster speeds simply require a direct-audio connection. My inexpensive solution here was to interface a Baofeng UV-5R to a soundcard: see attached file for details (for good engineering practice, 1:1 isolation transformers should be added to isolate the radio form the soundcard).
      Conveniently, Baofeng and other radios contain an inbuilt VOX circuit to control PTT. No additional interface needed (I recently purchased 3 for this project, hihi)

      I saw some testing months ago for a mode that could be used over FM repeaters.
      Here I am proposing a new digital mode: NBEMS-FM
      This not a mode that I am making, but rather one I think we all should contribute to and discuss together. This will result in a better overall design.

      The details of the NBEMS-FM mode should be, in my opinion:
       * 2 Speeds: one for Uplink / Reliability, one for Downlink / Backhaul
       * No options to accidentally mis-configure
       * Modem uses a set-frequency (no AFC to be mis-adjusted)
       * Little-to-no FEC overhead
       * Use PSK instead of QAM, to better allow for drastic audio-level mis-adjustments to still decode
       * Common-sense balance of speed and reliability


      In my testing here, it appears 8PSK is the highest constellation that is reliable over FM audio. I have tested on-air patches for fldigi that reliably transmitted data using two 8PSK carriers at 500 Baud, for a datarate (raw and net) of 3Kbps. Will work on porting those patches forward to the recent Fldigi versions.

      First thing that is required is the common audio upper and lower "cutoff frequencies" of amateur repeaters and radios.
      From the previous testing, what was the consensus?

      Responses and opinions  appreciated at: kl4yfd@..., or on the mailing list.

      John
      KL4YFD

    • Charles J. Hargrove
      Count the NYC-ARECS organization as being interested. We encourage members to use FLdigi on all bands along with other modes like packet, SSTV, etc. It s
      Message 2 of 8 , Jul 26, 2013
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        Count the NYC-ARECS organization as being interested. We encourage members
        to use FLdigi on all bands along with other modes like packet, SSTV, etc.
        It's better to have more available tools in the toolbox!

        > Hello all,
        > Apologies for the number of mailing-lists this touches, but am taking a bit
        > of a survey:
        >
        > Want see how many people would be interested in using, developing, and/or
        > testing Fldigi for "high speed" data over FM audio and/or FM-audio
        > repeaters. In my testing so far, it appears the speed would be somewhere in
        > the 3 Kb/s to 4 Kb/s range, possibly higher.
        >
        > Since the goal is fast data, audio coupling is out: faster speeds simply
        > require a direct-audio connection. My inexpensive solution here was to
        > interface a Baofeng UV-5R to a soundcard: see attached file for details
        > (for good engineering practice, 1:1 isolation transformers should be added
        > to isolate the radio form the soundcard).
        > Conveniently, Baofeng and other radios contain an inbuilt VOX circuit to
        > control PTT. No additional interface needed (I recently purchased 3 for
        > this project, hihi)
        >
        > I saw some testing months ago for a mode that could be used over FM
        > repeaters.
        > Here I am proposing a new digital mode: NBEMS-FM
        > This not a mode that I am making, but rather one I think we all should
        > contribute to and discuss together. This will result in a better overall
        > design.
        >
        > The details of the NBEMS-FM mode should be, in my opinion:
        > * 2 Speeds: one for Uplink / Reliability, one for Downlink / Backhaul
        > * No options to accidentally mis-configure
        > * Modem uses a set-frequency (no AFC to be mis-adjusted)
        > * Little-to-no FEC overhead
        > * Use PSK instead of QAM, to better allow for drastic audio-level
        > mis-adjustments to still decode
        > * Common-sense balance of speed and reliability
        >
        >
        > In my testing here, it appears 8PSK is the highest constellation that is
        > reliable over FM audio. I have tested on-air patches for fldigi that
        > reliably transmitted data using two 8PSK carriers at 500 Baud, for a
        > datarate (raw and net) of 3Kbps. Will work on porting those patches forward
        > to the recent Fldigi versions.
        >
        > First thing that is required is the common audio upper and lower "cutoff
        > frequencies" of amateur repeaters and radios.
        > From the previous testing, what was the consensus?
        >
        > Responses and opinions appreciated at: kl4yfd@..., or on the mailing
        > list.
        >
        > John
        > KL4YFD


        --
        Charles J. Hargrove - N2NOV
        NYC ARECS/RACES Citywide Radio Officer/Skywarn Coord.

        NYC-ARECS/RACES Net Mon. @ 8:30PM 147.360/107.2 PL
        http://www.nyc-arecs.org and http://www.nyc-skywarn.org

        NYDXA SWL & Scanner Net Wed. @ 9PM 147.360/107.2 PL
        http://www.n2nov.net

        "Information is the oxygen of the modern age. It seeps through the walls topped
        by barbed wire, it wafts across the electrified borders." - Ronald Reagan

        "The more corrupt the state, the more it legislates." - Tacitus

        "Molann an obair an fear" - Irish Saying
        (The work praises the man.)

        "No matter how big and powerful government gets, and the many services it
        provides, it can never take the place of volunteers." - Ronald Reagan
      • Tom_Pryts
        I want to echo Geoff N7PGN report on the use of MT63 2000L over 2m FM. Our ARES group uses it in support of our 911 center. we have sent Red Cross Forms to
        Message 3 of 8 , Jul 26, 2013
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          I want to echo Geoff N7PGN report on the use of MT63 2000L over 2m FM. Our ARES group uses it in support of our 911 center. we have sent Red Cross Forms to Pittsburgh using linking repeaters from some 75 miles away. Very fast so you can audio or Signal link with solid results.
          check out http://groups.yahoo.com/group/wpaares-digital/ for more information
          Tom, N3NTF
          Hermitage, PA
          EN91sf

          --- In linuxham@yahoogroups.com, Geoff McAlpin <geoff.n7pgn@...> wrote:
          >
          > Here in the Seattle area there is a group that uses MT-63 2000 over 2m FM.
          > They are actually using it over one of the local repeaters. In addition to
          > sending direct entry text, they are able to send image and document files
          > as well. I have listened in on a few of their nets and it seems to work
          > very well.
          >
          > Geoff, N7PGN
          > Seattle, WA
          > CN87tr
          > On Jul 26, 2013 11:06 AM, "John Phelps" <kl4yfd@...> wrote:
          >
          > > **
          > >
          > > [Attachment(s) <#1401c2932f2a365d_TopText> from John Phelps included
          > > below]
          > >
          > > Hello all,
          > > Apologies for the number of mailing-lists this touches, but am taking a
          > > bit of a survey:
          > >
          > > Want see how many people would be interested in using, developing, and/or
          > > testing Fldigi for "high speed" data over FM audio and/or FM-audio
          > > repeaters. In my testing so far, it appears the speed would be somewhere in
          > > the 3 Kb/s to 4 Kb/s range, possibly higher.
          > >
          > > Since the goal is fast data, audio coupling is out: faster speeds simply
          > > require a direct-audio connection. My inexpensive solution here was to
          > > interface a Baofeng UV-5R to a soundcard: see attached file for details
          > > (for good engineering practice, 1:1 isolation transformers should be added
          > > to isolate the radio form the soundcard).
          > > Conveniently, Baofeng and other radios contain an inbuilt VOX circuit to
          > > control PTT. No additional interface needed (I recently purchased 3 for
          > > this project, hihi)
          > >
          > > I saw some testing months ago for a mode that could be used over FM
          > > repeaters.
          > > Here I am proposing a new digital mode: NBEMS-FM
          > > This not a mode that I am making, but rather one I think we all should
          > > contribute to and discuss together. This will result in a better overall
          > > design.
          > >
          > > The details of the NBEMS-FM mode should be, in my opinion:
          > > * 2 Speeds: one for Uplink / Reliability, one for Downlink / Backhaul
          > > * No options to accidentally mis-configure
          > > * Modem uses a set-frequency (no AFC to be mis-adjusted)
          > > * Little-to-no FEC overhead
          > > * Use PSK instead of QAM, to better allow for drastic audio-level
          > > mis-adjustments to still decode
          > > * Common-sense balance of speed and reliability
          > >
          > >
          > > In my testing here, it appears 8PSK is the highest constellation that is
          > > reliable over FM audio. I have tested on-air patches for fldigi that
          > > reliably transmitted data using two 8PSK carriers at 500 Baud, for a
          > > datarate (raw and net) of 3Kbps. Will work on porting those patches forward
          > > to the recent Fldigi versions.
          > >
          > > First thing that is required is the common audio upper and lower "cutoff
          > > frequencies" of amateur repeaters and radios.
          > > From the previous testing, what was the consensus?
          > >
          > > Responses and opinions appreciated at: kl4yfd@..., or on the
          > > mailing list.
          > >
          > > John
          > > KL4YFD
          > >
          > >
          > >
          >
        • John Phelps
          Hi Remi, ... pseudo-tty interface. ... The NBEMS-FM mode (both speeds) would indeed work with your FT-817 and 99% of all radios or handhelds without
          Message 4 of 8 , Jul 27, 2013
          • 0 Attachment
            Hi Remi, 

            RE:
            | Will it be usable on a "normal" radio such as FT817 ?
            | Also, at 2400 bauds, it might be nice to add a Hayes-compatible pseudo-tty interface. 
            | It is fast enough to do a telnet connection.

            The NBEMS-FM mode (both speeds) would indeed work with your FT-817 and 99% of all radios or handhelds without modification. This is by design. Will not require a "9600 capable" radio, or have the touchy adjustments. Here I have been using my FT-857 and a UV-5R when testing FM modes and/or flarq. The audio-bandwidth will fit within nearly every radio and repeater with only a few very old or especially narrow devices excluded. 

            From received emails and my tests so far, it appears 500hz is the "safe" lower audio-frequency to use on VHF FM with 300Hz being the "cutoff". Am still uncertain what the best upper frequency-limit is, as this is a complex question. It should be compatible with as many radios and repeaters as possible, without being crippled just to support very old or specifically-narrow radios/repeaters. 

            I received permission recently to perform some late-night bandwidth tests on all the local repeaters to determine what the upper frequency limits are, both the "cutoff" value and the "safe" value.
            So far it is looking like 3Khz or higher. Still have more emails to read and run these tests though. Given the quality of most FM links and modern modulation schemes, 2400baud/2.4Kbps is definitely do-able.

            Telnet, simple HTTP, and XMPP-chat over a ham radio with fldigi would be amazing, and there is no reason it can't be done with an external program to fldigi (like flarq, flamp, flmsg, etc). Some more coding and testing will have to be done though, hihi.

            ~ John 
            kl4yfd


            On Sat, Jul 27, 2013 at 1:38 AM, Remi Chateauneu <remi.chateauneu@...> wrote:
            Will it be usable on a "normal" radio such as FT817 ?
            Also, at 2400 bauds, it might be nice to add a Hayes-compatible pseudo-tty interface. It is fast enough to do a telnet connection.

            Remi


            On Sat, Jul 27, 2013 at 7:06 AM, Guy Story KC5GOI <kc5goi@...> wrote:
            John, we have been using the multi-carrier PSK modes in Denton County on our bi-weekly net with good results for roughly a year.  I have to go looking for it but we found on our repeater that lower frequency audio get more emphasis and gradually rolls off the higher in frequency you go.  I have graphs of the data but I need to dig for it.  I can to that tomorrow during the VOA Radiogram.

            73

            Guy
            KC5GOI


            On Fri, Jul 26, 2013 at 12:47 PM, John Phelps <kl4yfd@...> wrote:
            Hello all,
            Apologies for the number of mailing-lists this touches, but am taking a bit of a survey:

            Want see how many people would be interested in using, developing, and/or testing Fldigi for "high speed" data over FM audio and/or FM-audio repeaters. In my testing so far, it appears the speed would be somewhere in the 3 Kb/s to 4 Kb/s range, possibly higher.

            Since the goal is fast data, audio coupling is out: faster speeds simply require a direct-audio connection. My inexpensive solution here was to interface a Baofeng UV-5R to a soundcard: see attached file for details (for good engineering practice, 1:1 isolation transformers should be added to isolate the radio form the soundcard).
            Conveniently, Baofeng and other radios contain an inbuilt VOX circuit to control PTT. No additional interface needed (I recently purchased 3 for this project, hihi)

            I saw some testing months ago for a mode that could be used over FM repeaters.
            Here I am proposing a new digital mode: NBEMS-FM
            This not a mode that I am making, but rather one I think we all should contribute to and discuss together. This will result in a better overall design.

            The details of the NBEMS-FM mode should be, in my opinion:
             * 2 Speeds: one for Uplink / Reliability, one for Downlink / Backhaul
             * No options to accidentally mis-configure
             * Modem uses a set-frequency (no AFC to be mis-adjusted)
             * Little-to-no FEC overhead
             * Use PSK instead of QAM, to better allow for drastic audio-level mis-adjustments to still decode
             * Common-sense balance of speed and reliability


            In my testing here, it appears 8PSK is the highest constellation that is reliable over FM audio. I have tested on-air patches for fldigi that reliably transmitted data using two 8PSK carriers at 500 Baud, for a datarate (raw and net) of 3Kbps. Will work on porting those patches forward to the recent Fldigi versions.

            First thing that is required is the common audio upper and lower "cutoff frequencies" of amateur repeaters and radios.
            From the previous testing, what was the consensus?

            Responses and opinions  appreciated at: kl4yfd@..., or on the mailing list.

            John
            KL4YFD


            _______________________________________________
            fldigi-alpha mailing list
            fldigi-alpha@...
            https://lists.berlios.de/mailman/listinfo/fldigi-alpha



            --
            73

            Guy Story KC5GOI
            kc5goi@...

            _______________________________________________
            fldigi-alpha mailing list
            fldigi-alpha@...
            https://lists.berlios.de/mailman/listinfo/fldigi-alpha


          • Steve
            With the latest version 3.21.77 of FLDIGI. OSX 10.8.5: When there is one call sign not found in cd database then ever after that until restarting the
            Message 5 of 8 , Nov 21, 2013
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              With the latest version 3.21.77 of FLDIGI. OSX 10.8.5:

              When there is one call sign not found in cd database then ever after that until restarting the application,
              any time you press the world button to lookup the call sign selected it puts not found in database in the comments field.
              you can't get rid of it. but of course it is found and all the other fields populate correctly. So it is being found.
              it's just that the not found comment keeps coming back no matter how many times you delete it or replace it with something else.
              it just comes back.

              help?

              Steve
              KK4NNH
            • Steve
              Message 6 of 8 , Nov 24, 2013
              • 0 Attachment
                > With the latest version 3.21.77 of FLDIGI. OSX 10.8.5:
                >
                > When there is one call sign not found in cd database then ever after that until restarting the application,
                > any time you press the world button to lookup the call sign selected it puts not found in database in the comments field.
                > you can't get rid of it. but of course it is found and all the other fields populate correctly. So it is being found.
                > it's just that the not found comment keeps coming back no matter how many times you delete it or replace it with something else.
                > it just comes back.
                >
                > help?
                >
                > Steve
                > KK4NNH
              • w1hkj
                press the broom button between CD data base searches. The notes field is designed to append information rather than overwrite. You may have added some notes
                Message 7 of 8 , Nov 24, 2013
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                  press the broom button between CD data base searches.  The notes field is designed to append information rather than overwrite.  You may have added some notes regarding the QSO and then pressed the search button.  In which case you would be unhappy with the developer who just erased your input.

                  Dave

                  On 11/24/2013 03:31 PM, Steve wrote:
                   


                  > With the latest version 3.21.77 of FLDIGI. OSX 10.8.5:
                  >
                  > When there is one call sign not found in cd database then ever after that until restarting the application,
                  > any time you press the world button to lookup the call sign selected it puts not found in database in the comments field.
                  > you can't get rid of it. but of course it is found and all the other fields populate correctly. So it is being found.
                  > it's just that the not found comment keeps coming back no matter how many times you delete it or replace it with something else.
                  > it just comes back.
                  >
                  > help?
                  >
                  > Steve
                  > KK4NNH


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