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Re: [tracker2] Re: looking for a comprehensive list of aprs digipeaters

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  • Eric Fort
    On Wed, Oct 3, 2012 at 11:28 AM, Craig Lumpy Lemke
    Message 1 of 14 , Oct 3, 2012
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      On Wed, Oct 3, 2012 at 11:28 AM, Craig 'Lumpy' Lemke <lumpy@...> wrote:
      Eric Fort wrote:


      > I specifically asked not for issues of routing but to get an idea of
      > coverage for a proposed vacation route...

      I didn't see that you "specifically asked nor for issues of routing".
      What I saw was you asked for a list of digipeaters. I suggest that
      a list of that nature borders on useless in trying to determine
      coverage.

      Much, much simpler, is to view the system in real time. Go to aprs.fi
      and view the area you want to travel in. See if other stations and mobiles
      are being digipeated. THAT will give you an accurate guess as to if you
      will be covered. A list of digi's won't.

      And in the bigger picture, knowing (guessing) that there is or isn't
      coverage in any particular area won't get you coverage. If you travel
      into an area without coverage, nothing you can do will change that.
      You won't reach the network. And conversely, traveling into an area
      that does have coverage is seamless. There's no settings to change.

      My apologies if you already knew all this. It appeared by your
      initial post that you weren't very familiar with how the network works.


      Craig 'Lumpy' Lemke

      www.n0eq.com

      I'm not all that familiar with how the aprs network works, but I do know that by knowing the locations of voice repeaters and other fixed radios in an area I can at least get a vague idea of the coverage and service area they provide.  It's also pretty obvious - no radio, no coverage.  Viewing traffic in real time only shows that there is traffic happening.  There could be infrastructure in an area that sees little use, thus the nodes are there, but little traffic.  In an area like the quiet zone where they'd prefer few to none intentional or even unintentional radiators I might suspect that very few would exist.  There's more than I figured.  The map (listing) also shows the calls of those who operate radio's in the area of interest which with the help of qrz one can contact those operators local to an area and get more info.  This I've done.  It's also been good to learn a bit more about the aprs network along the way.

      Eric
      AF6EP
    • Craig 'Lumpy' Lemke
      ... I think it certainly will be real time in terms of what the OP is trying to discover. Is there coverage in an area I m going to travel in? Look on aprs.fi
      Message 2 of 14 , Oct 4, 2012
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        Lynn W. Deffenbaugh wrote:

        > Pardon my picking of the nits, but
        > "view the system in real time" is
        > not going to be accomplished by "go to aprs.fi".
        >
        > Due to the duplicate packet filtering enforced
        > by the APRS-IS transport from which aprs.fi draws
        > all of its information, and the fact that
        > aprs.fi shows you stations from its accumulated
        > database based on selected time window, all you'll
        > get on an aprs.fi display is a time-windowed accumulation
        > of stations and the route their respective
        > FIRST packet to reach an IGate took.

        I think it certainly will be real time in terms of what
        the OP is trying to discover. Is there coverage in an area
        I'm going to travel in? Look on aprs.fi and I'll know.

        Do I know exactly the route my packet took? How many hops
        it was digi'd? Sometimes, absolutely yes. But even when the
        answer is "no" it doesn't make a difference for the question
        of "is there coverage". If I see mobile APRS stations
        hitting a digi, I'm quite confident there's coverage in the
        area between those mobiles.

        Consider the "list of digi's" approach.

        Here's a list of three fictitional digi's -

        W7AAA - 39.0 112.0 1400'
        W7BBB - 39.2 111.2 2200'
        W7CCC - 38.2 112.2 875'

        Is there any possible way to infer what kind of coverage
        there is in that area? I'm quite certain there isn't.

        But go to aprs.fi and VIEW the area in question. I'm quite
        certain I can ascertain if there is coverage in that area.
        Is it "real time"? Define the definition. If I send an RF
        packet to the network, I see it on aprs.fi in seconds. But
        even if it wasn't that fast, the digi's don't move. If stations
        are hitting digis they're doing it 24/7. Even if we were viewing
        them in time delay, the coverage wouldn't change.


        Craig 'Lumpy' Lemke

        www.n0eq.com
      • Craig 'Lumpy' Lemke
        ... Traffic happening is what APRS is. If there are nodes (they aren t typically called notes in unconnected packet like APRS) we see them. They beacon.
        Message 3 of 14 , Oct 4, 2012
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          Eric Fort wrote:

          > Viewing traffic in real time only shows that there is
          > traffic happening. There could be infrastructure in
          > an area that sees little use, thus the nodes are
          > there, but little traffic. In an area like the quiet
          > zone where they'd prefer few to none intentional or
          > even unintentional radiators I might
          > suspect that very few would exist. There's more than
          > I figured. The map (listing) also shows the calls of
          > those who operate radio's in the area of
          > interest which with the help of qrz one can
          > contact those operators local
          > to an area and get more info.
          > This I've done. It's also been good to
          > learn a bit more about the aprs network along the way.

          "Traffic happening" is what APRS is. If there are "nodes"
          (they aren't typically called notes in unconnected packet
          like APRS) we see them. They beacon. They ALL beacon. Some
          also digi. But there are no APRS stations that are lying in
          wait to be "woken up" by traffic. Or to put it another way,
          if you don't see "traffic" there IS no "infrastructure".

          Perhaps look at it this way...What is the desired outcome
          of your research into the area in question? Are you traveling
          there and want friends and relatives to see your icon on the web?
          If that's the scenario, you can find out if that will happen or
          not right now. Just view the web based APRS sites. If you see
          other mobiles in the area, then YOU will be seen when you're
          in the area.

          It's really much simpler than it sometimes seems. We beacon
          our packets, they either get picked up or they don't. It's
          not like we're (usually) communicating 2-way like we do on
          a 2m or UHF repeater.

          I suspect I've kind of set you off a bit. It really was not
          my intention. My apologies if I did. Perhaps someone else
          can explain it in a way which seems more logical. Simple,
          bottom line answer is - Just beacon your packets. The
          network does the rest magiriffically.


          Lumpy

          You Played on Lawrence Welk?
          Yes but no blue notes. Just blue hairs.

          www.LumpyMusic.com
        • Eric Fort
          Craig, Yes what I was looking for here was if a station passes through an area, will it bee seen. the means of figuring that out has been demonstrated and
          Message 4 of 14 , Oct 4, 2012
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            Craig,

            Yes what I was looking for here was if a station passes through an area, will it bee seen.  the means of figuring that out has been demonstrated and along the way as well as me learning a bit more about how things work along the way.  not off putting at all, simply educational and for that I thank everyone that has participated.

            Eric

            On Thu, Oct 4, 2012 at 4:15 PM, Craig 'Lumpy' Lemke <lumpy@...> wrote:
            Eric Fort wrote:

            > Viewing traffic in real time only shows that there is
            > traffic happening. There could be infrastructure in
            > an area that sees little use, thus the nodes are
            > there, but little traffic.  In an area like the quiet
            > zone where they'd prefer few to none intentional or
            > even unintentional radiators I might
            > suspect that very few would exist.  There's more than
            > I figured. The map (listing) also shows the calls of
            > those who operate radio's in the area of
            > interest which with the help of qrz one can
            > contact those operators local
            > to an area and get more info.
            > This I've done.  It's also been good to
            > learn a bit more about the aprs network along the way.

            "Traffic happening" is what APRS is. If there are "nodes"
            (they aren't typically called notes in unconnected packet
            like APRS) we see them. They beacon. They ALL beacon. Some
            also digi. But there are no APRS stations that are lying in
            wait to be "woken up" by traffic. Or to put it another way,
            if you don't see "traffic" there IS no "infrastructure".

            Perhaps look at it this way...What is the desired outcome
            of your research into the area in question? Are you traveling
            there and want friends and relatives to see your icon on the web?
            If that's the scenario, you can find out if that will happen or
            not right now. Just view the web based APRS sites. If you see
            other mobiles in the area, then YOU will be seen when you're
            in the area.

            It's really much simpler than it sometimes seems. We beacon
            our packets, they either get picked up or they don't. It's
            not like we're (usually) communicating 2-way like we do on
            a 2m or UHF repeater.

            I suspect I've kind of set you off a bit. It really was not
            my intention. My apologies if I did. Perhaps someone else
            can explain it in a way which seems more logical. Simple,
            bottom line answer is - Just beacon your packets. The
            network does the rest magiriffically.


            Lumpy

            You Played on Lawrence Welk?
            Yes but no blue notes. Just blue hairs.

            www.LumpyMusic.com





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          • James Ewen
            On Thu, Oct 4, 2012 at 2:49 PM, Craig Lumpy Lemke
            Message 5 of 14 , Oct 5, 2012
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              On Thu, Oct 4, 2012 at 2:49 PM, Craig 'Lumpy' Lemke <lumpy@...> wrote:

              > I think it certainly will be real time in terms of what
              > the OP is trying to discover. Is there coverage in an area
              > I'm going to travel in? Look on aprs.fi and I'll know.

              The original question was asking for a list of digipeaters, and the coverage in the areas in question.

              > Do I know exactly the route my packet took? How many hops
              > it was digi'd? Sometimes, absolutely yes. But even when the
              > answer is "no" it doesn't make a difference for the question
              > of "is there coverage". If I see mobile APRS stations
              > hitting a digi, I'm quite confident there's coverage in the
              > area between those mobiles.

              The information displayed at aprs.fi will not always provide the information that you say it will. You can get a partial picture of what is happening out there, but not a full picture.

              Much of the APRS RF network is hidden from the APRS-IS by the filtering that takes place as packets are moved from RF to the APRS-IS. Only the first packet to get into the APRS-IS stream is kept.

              Take an example where there are 4 digipeaters that can hear an area, and an i-gate as well. Send a packet out into that network, and the i-gate will pass the packet directly to the APRS-IS first. The packet will also bounce off the 4 digipeaters, and the i-gate will hear those 4 digipeats. The i-gate will try to forward the copies on to the APRS-IS stream, but the first heard only filter will drop the copies. For the observer on the internet, they would never know that the digipeaters can hear into the area.

              > But go to aprs.fi and VIEW the area in question. I'm quite
              > certain I can ascertain if there is coverage in that area.
              > Is it "real time"? Define the definition. If I send an RF
              > packet to the network, I see it on aprs.fi in seconds. But
              > even if it wasn't that fast, the digi's don't move. If stations
              > are hitting digis they're doing it 24/7. Even if we were viewing
              > them in time delay, the coverage wouldn't change.

              The issue isn't chronologic, but completeness of the data being observed.

              In the Edmonton area we have a number of digipeaters. Many of these can hear quite a bit of traffic, and our RF network works very well. We also have some i-gates with HUGE ears. The LAMONT RX only i-gate sits on a hilltop at a world class contesting station VE6JY. It can hear packets directly for a long distance. The CHPMAN digipeater sits a couple miles away. CHPMAN can hear fairly well itself, but looking at aprs.fi's coverage plot based on filtered data only shows a subset of the coverage area.

              Inline image 1

              Inline image 2

              aprs.fi does not show any of the packets that were heard in the City of Edmonton. Those were passed to the internet via one of the 5 or 6 i-gates running in town before CHPMAN handled the packet.

              Looking at aprs.fi, you can tell if something heard a packet in the area in question, but getting a full idea of the area of coverage of a specific digipeater from the available data is impossible.

              You could put up a wonderful network of i-gates fully covering an area, and aprs.fi would show that there's great coverage, but drive through the area and you'll never heard a digipeat, and will only hear others within simplex range since there are no digipeaters in the area.

              Of course the opposite is also true... you could be in an area with wonderful digipeater coverage, but with no i-gates around, one could assume that there's no coverage due to what can be observed via the APRS-IS stream.

              As long as you are aware that the APRS-IS stream only provides visibility of a small subset of the available data, and that it is skewed towards showing i-gate coverage versus RF coverage, you're good to go...

              -- 
              James
              VE6SRV
            • Tony VE6MVP
              ... In Feb/March of this year I travelled from Alberta to British Columbia in areas where there were no digipeaters for hours at a time. I was using my
              Message 6 of 14 , Oct 5, 2012
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                At 05:15 PM 2012-10-04, Craig 'Lumpy' Lemke wrote:

                >"Traffic happening" is what APRS is. If there are
                "nodes"
                >(they aren't typically called notes in unconnected packet
                >like APRS) we see them. They beacon. They ALL beacon. Some
                >also digi. But there are no APRS stations that are lying in
                >wait to be "woken up" by traffic. Or to put it another
                way,
                >if you don't see "traffic" there IS no
                "infrastructure".

                In Feb/March of this year I travelled from Alberta to British Columbia in areas where there were no digipeaters for hours at a time.   I was using my Kenwood D710 at the time and listening to the APRS audio.

                The definition of loneliness for an APRS mobile operator is not hearing yourself being digipeated.  <smile>

                Some of those areas I drove through particularly in East Central Alberta now have digi's.    

                Tony
              • Craig 'Lumpy' Lemke
                ... There is no list that will suggest any kind of coverage. I think the answers the OP received from everyone pointed that out. ... It will for my purposes.
                Message 7 of 14 , Oct 5, 2012
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                  James Ewen wrote:

                  > The original question was asking for a list of digipeaters, and the
                  > coverage in the areas in question.

                  There is no "list" that will suggest any kind of coverage.
                  I think the answers the OP received from everyone pointed
                  that out.



                  > The information displayed at aprs.fi will not always provide the
                  > information that you say it will.

                  It will for my purposes. And I suggest it will for the purpose
                  the OP was asking. "Is there coverage in some area?" aprs.fi will
                  answer that clearly, every time. If there's any "hidden stations"
                  they're not configured appropriately and therefore are of no
                  use to the question "Is there coverage?". If I want to know about
                  coverage, I don't care about subsequent packets. I only care if
                  it's hitting a digi and/or gate.

                  Bottom line - "Is there coverage?", look on aprs.fi and you'll know.


                  Lumpy

                  You played on "The Love Boat"?
                  Yes. White tux, huge sideburns.

                  www.LumpyMusic.com
                • James Ewen
                  On Fri, Oct 5, 2012 at 2:43 PM, Craig Lumpy Lemke ... That would be an inaccurate statement... Look for any APRS activity that you can find near Otter Lake,
                  Message 8 of 14 , Oct 5, 2012
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                    On Fri, Oct 5, 2012 at 2:43 PM, Craig 'Lumpy' Lemke
                    <lumpy@...> wrote:

                    >> The information displayed at aprs.fi will not always provide the
                    >> information that you say it will.
                    >
                    > It will for my purposes. And I suggest it will for the purpose
                    > the OP was asking. "Is there coverage in some area?" aprs.fi will
                    > answer that clearly, every time. If there's any "hidden stations"
                    > they're not configured appropriately and therefore are of no
                    > use to the question "Is there coverage?". If I want to know about
                    > coverage, I don't care about subsequent packets. I only care if
                    > it's hitting a digi and/or gate.
                    >
                    > Bottom line - "Is there coverage?", look on aprs.fi and you'll know.

                    That would be an inaccurate statement...

                    Look for any APRS activity that you can find near Otter Lake, Alberta.
                    I was up there a month ago, and had my Kenwood D710 operating as a
                    digipeater. I had my D72 sending packets, and being digipeated by the
                    D710. Show me that you can find a record of that operation.

                    You will not be able to as there is no other APRS infrastructure in
                    place in the area. No digipeaters, no i-gates, no users. Looking at
                    aprs.fi will not show that there was coverage in that area.

                    You seem to want to ignore the salient point of this whole
                    discussion... the APRS-IS stream is but a fraction of the available
                    data. Only that which makes it to an i-gate and is the first packet
                    handled is ever seen on the APRS-IS stream.

                    That which is available on the APRS-IS stream has indeed been heard by
                    an i-gate, and possibly a digipeater or digipeaters enroute to that
                    i-gate, but in no way can it be seen as the complete and whole image
                    of what is actually available on RF.

                    If all you care about is being seen via aprs.fi, then your statements
                    are accurate. If you can see someone else on aprs.fi in the area in
                    question, then you have a chance of being seen on aprs.fi from that
                    area as well.

                    --
                    James
                    VE6SRV
                  • Craig 'Lumpy' Lemke
                    ... OK. Sir. You win. There are apparently thousands of stations digipeating other stations in the area in which you operate and they don t show up on the web
                    Message 9 of 14 , Oct 6, 2012
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                      James Ewen wrote:


                      > That would be an inaccurate statement...

                      OK. Sir. You win.
                      There are apparently thousands of stations digipeating
                      other stations in the area in which you operate and
                      they don't show up on the web feeds.


                      Craig 'Lumpy' Lemke

                      www.n0eq.com
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