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Re: [Q15X25] HF APRS and Q15X25 ?

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  • Jose Amador
    ... than 300 baud packet with 600 watts in much shorter ... Pactor II. ... Seems to be a matter of luck, as many other things in the human existence. And
    Message 1 of 17 , Sep 30, 2005
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      --- kd4e <kd4e@...> wrote:

      > > Something I did not mention on my other reply. I
      > > had to run 600 watts to "achieve" some 100 kb of
      > > compressed fwd per day.
      > >
      > > With pactor, 25 to 100 watts were able to move
      > > ten times more traffic. I had a link with Africa
      > > for forwarding to Europe which worked many times
      > > with as little as 25 watts with better thruput
      than > > 300 baud packet with 600 watts in much
      shorter
      > > links.

      > Which version of Pactor, please?

      Pactor II.

      > Pactor III is proprietary and expensive and thus not
      > an available tool for most Hams.

      > It may be superior in certain ways and not in others
      > but since it is not affordable nor healthy for Ham
      > radio it is not the answer to the need.

      Seems to be a matter of luck, as many other things in
      the human existence.

      And of course, the need arises from the fact that
      something much better than packet exists and is not
      widely available.

      Plain pactor with memory ARQ achieves a thereshold 10
      dB lower than RTTY, and P II 18 dB lower. That may
      explain the lower power required to establish a link.

      Since it is a one to one link, there are no
      collissions, perhaps, maybe, ocassional QRM from
      others who consider to own certain frequencies. The
      transfer protocol is more elaborate and better
      (compression, interleaving, convolutional encoding,
      Viterbi decoding, etc).

      No wonder that some techniques used for space
      communications can also help in terrestrial comms.

      I have been following Q15X25 as it may have better
      characteristics, those of modern HF data
      communications systems.

      Certainly, 300 baud FSK is far from optimal.

      Q15X25 and similar modulation methods may allow to
      have more people to communicate with on HF. With
      recent developments, there seems to be hope for may of
      us.

      73 de Jose, CO2JA
    • kd4e
      ... If I recall Pactor II may be monitored without the costly proprietary SCS hardware and software, so it may be a more acceptable app in Ham use -- at least
      Message 2 of 17 , Oct 1, 2005
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        > Since it is a one to one link, there are no
        > collissions, perhaps, maybe, ocassional QRM from
        > others who consider to own certain frequencies. The
        > transfer protocol is more elaborate and better
        > (compression, interleaving, convolutional encoding,
        > Viterbi decoding, etc).

        If I recall Pactor II may be monitored without the
        costly proprietary SCS hardware and software, so it
        may be a more acceptable app in Ham use -- at least
        one may determine who the QRMing offender is and
        report them -- one may also determine is the op is
        sending Ham-legal communications or something else.

        QRMing is rarely against folks camoing out on a
        freq 24/7 but most often the result of someone
        engaged in a QSO where another op is too careless
        or selfish to bother to check for activity and
        who jumps on top of them.

        There is no lack of space on the bands, except perhaps
        during the all-too-frequent contests, so there is no
        excuse for QRMing -- especially witha digital signal
        that cannot be decoded by 99% of Hams and may be
        readily abused for non-Ham legal or nefarious purposes

        > I have been following Q15X25 as it may have better
        > characteristics, those of modern HF data
        > communications systems.

        That is why we are all on this list.

        > Certainly, 300 baud FSK is far from optimal.

        For sure -- but that may also be a regulatory quirk
        choking-off new technologies that needs to be addressed.

        > Q15X25 and similar modulation methods may allow to
        > have more people to communicate with on HF. With
        > recent developments, there seems to be hope for may of
        > us.

        Agreed.

        > 73 de Jose, CO2JA
      • Jose Amador
        ... It might fit in your frame if we used, as you do, a BBS only frequency. We did not, anyone could connect freely. Perhaps that´s part of my problem with
        Message 3 of 17 , Oct 1, 2005
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          --- Charles Brabham <n5pvl@...> wrote:

          > --- In Q15X25@yahoogroups.com, Jose Amador
          > <co2ja@y...> wrote:
          > >
          > > Something I did not mention on my other reply. I
          > had
          > > to run 600 watts to "achieve" some 100 kb of
          > > compressed fwd per day.
          > >
          > > With pactor, 25 to 100 watts were able to move
          > ten
          > > times more traffic. I had a link with Africa for
          > > forwarding to Europe which worked many times with
          > as
          > > little as 25 watts with better thruput than 300
          > baud
          > > packet with 600 watts in much shorter links.
          > >
          > > Jose, CO2JA
          >
          > Personally, I have never heard of a Packet BBS SYSOP
          > before who ran
          > more than 50-70 watts power. If you were running 600
          > watts, that may
          > have been part of your problem with Packet.

          > Were the stations you connected to all running 600
          > watts too? - Or
          > were they running 50-70 watts, as all the SYSOPs I
          > know have found to
          > be work out best? ( I know a lot of SYSOPs, by the
          > way. )

          It might fit in your frame if we used, as you do, a
          BBS only frequency. We did not, anyone could connect
          freely.

          Perhaps that´s part of my problem with packet, I hate
          losing time with bad links and retries. I was able to
          do it, those were my finals and my power bill, at the
          service of my users. And it never caused problems to
          anyone. I do not operate a HF packet forwarding link
          since 1998. With pactor, or whatever replaces 300 baud
          FSK modems, it is not necessary to run high power to
          run a reliable link.

          > Your story doesn't make a lot of sense... I have
          > operated both modes
          > and though PACTOR does give better throughput, it
          > does not do so for
          > all of the BBS software currently in use.

          So, what makes sense is to use the BEST BBS software.

          I understand it does not make sense to you, but not
          all BBS programmers (and I do not mean to offend any
          of them) are equally gifted. Only the best software
          did survive.

          > PACTOR is also prohibitively expensive, and has
          > virtually no signal
          > detection capability, very often making PACTOR
          > operators into
          > unwilling ( and unwitting ) lids. Lots of BBS SYSOPs
          > won't go for
          > being party to that.

          I do not want to impose that on anyone. Have I meant
          that? Never.

          > Add the greatly expanded bandwidth of the higher
          > performing PACTOR
          > modes, and you have a nice QRM generation system
          > there, second to
          > none when it comes to crashing people's QSO's.

          Pactor 2 fits into my CW filter.

          > Then there is the difficulty in trying to operate
          > multiple PACTOR
          > QSO's on a single frequency. Packet handles this
          > just fine, PACTOR
          > does not.

          Pactor is not meant to do that. If you operated it,
          and read the manual, you know that it does not make
          sense to make that comparison.

          > Most SYSOPs utilize Packet because nothing better
          > has come along to
          > replace it. - You are welcome to consider PACTOR as
          > a 'better'
          > replacemnent for Packet if you wish, but understand
          > that by doing so,
          > you place yourself with a tiny minority among BBS
          > SYSOPs, for the
          > reasons outlined above.

          I do not do Internet forwarding. And you might know
          that time in HF forwarding counts, when the bands are
          not open 24/24 like a wire or VHF/UHF.

          > That's just how it is, agree with it or not as you
          > wish. Whatever
          > PACTOR is, it is not a "replacement" for Packet. -
          > Good or bad.
          >
          > Charles, N5PVL

          I respect your point of view, you are entitled to it.

          But I also feel I have the right to disagree. As I
          disagree to go into a name calling fight that solves
          nothing.

          And period. End of the thread, at least for me, it is
          not relevant to Q15X25.

          Jose
        • Mark Miller
          ... Do you recall how this is done? I have only seen monitoring software for PACTOR I and am interested in monitoring PACTOR II. 73, Mark N5RFX
          Message 4 of 17 , Oct 4, 2005
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            At 07:43 AM 10/1/2005, you wrote:
            >If I recall Pactor II may be monitored without the
            >costly proprietary SCS hardware and software, so it
            >may be a more acceptable app in Ham use --

            Do you recall how this is done? I have only seen monitoring software for
            PACTOR I and am interested in monitoring PACTOR II.

            73,

            Mark N5RFX
          • wb8wka
            APRS is not tied to AX.25. Most of the display programs as well as internet servers let you input data in a text format. The APRS spec is here:
            Message 5 of 17 , Oct 7, 2005
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              APRS is not tied to AX.25. Most of the display programs as well as
              internet servers let you input data in a text format. The APRS spec is
              here: http://www.tapr.org/aprs_working_group.html

              Being most APRS position reports are from 13 to 40 bytes long (native
              APRS format) you don't need the speed of Q15X25. Also, most APRS
              transmissions in the wild are UI frames, or unacknowledged information
              frames. Meaning, they don't use the connected mode (or ARQ) function
              of ax.25.

              If your looking to optimize HF APRS from the present AX.25 UI frame
              300 baud means, you'd be better off looking at a mode that offers
              heavy FEC and good low signal performance. MT63, MFSK16 or perhaps
              Olivia come to mind. All offer good low signal performance and heavy
              FEC.

              300 baud on HF, as a signaling rate, is less then optimal due to group
              delay caused by different paths through the ionosphere. That is the
              reason Q15X25 reduced the baud rate to 83.5 (on each carrier) to
              reduce this effect.

              Good luck.



              --- In Q15X25@yahoogroups.com, Tapio Sokura <oh2kku@i...> wrote:
              >
              > Hi,
              >
              > I was wondering if there are any established a) frequencies and/or
              b)
              > Q15X25 modem parameters for HF APRS use? 300 bps packet seems to be
              a
              > lot less than optimal on HF and it would be interesting to see how
              > Q15X25 would do instead. I did some googling on this subject, but
              didn't
              > find any concrete information on frequencies/parameters, just some
              pages
              > that mention the possibility of combining the two.
              >
              > Tapio
              >
            • Charles Brabham
              ... If you are not operating within the automated sub-bands, then you are most definately QRM ing other hams with your PACTOR signals. The one and only place
              Message 6 of 17 , Oct 8, 2005
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                > > Were the stations you connected to all running 600
                > > watts too? - Or
                > > were they running 50-70 watts, as all the SYSOPs I
                > > know have found to
                > > be work out best? ( I know a lot of SYSOPs, by the
                > > way. )
                >
                > It might fit in your frame if we used, as you do, a
                > BBS only frequency. We did not, anyone could connect
                > freely.

                If you are not operating within the automated sub-bands, then you are
                most definately QRM'ing other hams with your PACTOR signals.

                The one and only place where you can operate PACTOR ( or Packet ) for
                BBS operation without regularly crashing people's QSO's are the
                automated sub-bands.

                That's why they exist.

                Packet BBS operation as a 'loner' who does not play by the rules
                other SYSOPs operate by is a pointless endeavor. Competent
                autoforwarding's first requirement is an ability to play well with
                others, in a cooperative way and friendly way.

                > With pactor, or whatever replaces 300 baud
                > FSK modems, it is not necessary to run high power to
                > run a reliable link.

                You are the one and only amateur who has ever suggested to me that
                Packet is unreliable except when using high power.

                From my location at the southern tip of Texas, I forward regularly
                with stations in Canada, California, Indiana, Florida and ( Here's an
                easy one ) Missouri. - All with 50 watts on HF Packet.

                > > Your story doesn't make a lot of sense... I have
                > > operated both modes
                > > and though PACTOR does give better throughput, it
                > > does not do so for
                > > all of the BBS software currently in use.
                >
                > So, what makes sense is to use the BEST BBS software.

                http://www.uspacket.org/l_protowars.htm

                What makes sense is to work with protocols/modes that are usable by
                all BBS software, including the new BBS software that is coming up.

                > > Then there is the difficulty in trying to operate
                > > multiple PACTOR
                > > QSO's on a single frequency. Packet handles this
                > > just fine, PACTOR
                > > does not.
                >
                > Pactor is not meant to do that. If you operated it,
                > and read the manual, you know that it does not make
                > sense to make that comparison.

                Looks like you are picking and choosing what is or is not 'relevant'
                according to how well it matches up with your personal views.

                As manager of an ARRL Skipnet, I can assure you that the ability to
                operate half a dozen or more stations on one frequency is highly
                relevant, unless and until somebody comes along and finds a way to
                greatly expand the autoforwarding sub-bands.

                If we can only have two stations per frequency, and those stations
                must be five or six times wider, that means that the network can only
                have a few participating stations, and so it would have very little
                coverage or capability, worldwide.

                We are trying to get more BBS stations to participate, not to shut
                them out by using inappropriate modes/protocols that do not 'play
                well with others' and so reduce our capability in this area.

                It should never be forgotten that participation in a network is a
                cooperative venture. Your value to that network in large part hinges
                upon your ability to work cooperatively with many other hams around
                the world.

                >
                > I respect your point of view, you are entitled to it.
                >
                > But I also feel I have the right to disagree. As I
                > disagree to go into a name calling fight that solves
                > nothing.
                >
                > And period. End of the thread, at least for me, it is
                > not relevant to Q15X25.
                >

                Right now I am manager of the NET117 ARRL SkipNet, experimenting with
                utilizing Q15x25 mode for autoforwarding. In my case at any rate,
                these questions and discussions are highly relevant to what I do.

                I have to think about stuff like bandwidth, signal strength, the
                ability to share a frequency, bitrate, compatability with all ( not
                just my personal favorite ) BBS software and ease of operation, along
                with a number of other factors.

                Personally I would like to see Q15x25 mode go into regular use for
                autoforwarding - but it is not my job to promote Q15x25. What I am
                doing is evaluating the mode instead, doing my best to give it a fair
                chance to show it's stuff. - Both good and bad.

                I'm beginning to wonder if 17 meters is the best place to do this
                evaluation, but that's the spot the ARRL folks gave me so that's what
                I have to work with right now. - I sure wish 15 meters was open more
                often!

                Charles, N5PVL
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