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    Hello Dom, All,<br>
    <br>
    An interesting possible explanation, and it may partly account for
    the observations.<br>
    <br>
    However, here is one of TKK's posits:<br>
    <br>
    <span class="raw_line">2014-09-23 12:02:47 EST: <b><a
          href="http://aprs.fi/?c=raw&limit=&call=VK3TKK-9">VK3TKK-9</a></b>>ST43ZL,<a
        href="http://aprs.fi/?c=raw&limit=&call=VK2AMW-1">VK2AMW-1*</a>,WIDE2-1,qAR,<a
        href="http://aprs.fi/?c=raw&limit=&call=VK2NR-5">VK2NR-5</a>:`MV<span
        class="raw_bin"><0x1c></span>qzZ>/`";3}Just cruising ^:-}_"</span><br>
    <span class="raw_line">2014-09-23 12:02:48 EST: <b><a
          href="http://aprs.fi/?c=raw&limit=&call=VK3TKK-9">VK3TKK-9</a></b>>ST43ZL,<a
        href="http://aprs.fi/?c=raw&limit=&call=VK2AMW-1">VK2AMW-1</a>,<a
        href="http://aprs.fi/?c=raw&limit=&call=VK2RTZ-1">VK2RTZ-1</a>,WIDE2*,qAR,<a
        href="http://aprs.fi/?c=raw&limit=&call=VK2ZEN-5">VK2ZEN-5</a>:`MV qzZ>/`";3}Just cruising ^:-}_" </span><br>
    <span class="raw_line"><br>
      Look at the  </span><span class="raw_line"><span class="raw_bin"><0x1c>
        in NR's submission, and see that in ZEN's for the same posit,
        there is a blank.<br>
        <br>
        Some software developers think that AX.25 packets contain
        printable characters, and substitute non-printables (eg with a
        space as here) and so corrupt the packets. It seems aprsd
        developers may have thought that way.<br>
        <br>
        MICE packets are not purely printable characters, and it is
        presumptuous for any server handling traffic to edit the
        contents of a another parties packet 'info' section.<br>
        <br>
        I think this problem in aprsd has been known for more than a
        decade.<br>
        <br>
        Best way to avoid position reports if that is a concern is to
        turn the thing off, and it saves bandwidth otherwise utilised by
        garbage!<br>
        <br>
        73<br>
        Owen<br>
        <br>
        <br>
      </span></span>
    <div class="moz-cite-prefix">On 23/09/2014 15:26, Dom Dahl wrote:<br>
    </div>
    <blockquote
cite="mid:CANkT2uPtOQmNXjYswzkyJgtw25=0dmrTS_F=6aUuEhOooLxn5w@mail.gmail.com"
      type="cite">
      <div dir="ltr">
        <div>
          <div>
            <div>Hi Owen<br>
              <br>
            </div>
            I thought the same thing to start with but his whole track
            was from goulburn was all over the place. (I didn't look
            back any futher)<br>
            <br>
          </div>
          I was reading this the othe day and i think this would explain
          what VK3TKK-9 setup is. Its more a security thing. Who knows
          why you would use it but some people just really don't want
          you to know there exact location.<br>
          <br>
        </div>
        Cheers<br>
        <br>
        Dom<br>
        <div><br>
          <h2> <span class="" id="Ambiguous_positions">Ambiguous
              positions</span></h2>
          <p>Many APRS transmitters using MIC-E or uncompressed packets
            can be configured to intentionally transmit less precise
            positions. This may seem a bit backward at first, but there
            are perfectly good reasons to do so. Some people might want
            to transmit a rough location of their car without revealing
            the exact parking spot where their expensive radio gear
            spend their night in. Some might like some aspects of APRS
            but wish to adjust the level of privacy by hiding their
            precise location.
          </p>
          <p>Ambiguity is configured by setting the number of digits
            which will be truncated from the end of the position.
            Plaintext APRS positions are transmitted in degrees and
            decimal minutes (DD° MM.mm'), with two decimals of minutes.
            When ambiguity is set to 1, it'll be truncated to DD° MM.m',
            2 will transmit DD° mm', 4 will transmit DD° only, resulting
            in a resolution of 1 degree.
          </p>
          <p>The station in the following image has chosen to send
            positions with 1 digit of precision reduced. It can be seen
            that the car is driving the ring road, but the positions are
            slightly off.
          </p>
          <br>
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      <div class="gmail_extra"><br>
        <div class="gmail_quote">On Tue, Sep 23, 2014 at 3:00 PM, owen <span
            dir="ltr"><<a moz-do-not-send="true"
              href="mailto:owen@owenduffy.net" target="_blank">owen@owenduffy.net</a>></span>
          wrote:<br>
          <blockquote class="gmail_quote" style="margin:0 0 0
            .8ex;border-left:1px #ccc solid;padding-left:1ex">Hello All,<br>
            <br>
            In the past, I have been a devotee of MIC encoding as it
            reduced packet<br>
            size, reducing channel utilisation and increasing
            probability of<br>
            successful transmission.<br>
            <br>
            But... I have review that position seeing the existence and
            continued<br>
            operation of nodes that corrupt MICE packets.<br>
            <br>
            An example of the effect is VK3TKK-9's track up the Hume
            today, see<br>
            <a moz-do-not-send="true"
href="http://owenduffy.net/files/Screenshot%20-%2023_09_2014%20,%2013_20_03.png"
              target="_blank">http://owenduffy.net/files/Screenshot%20-%2023_09_2014%20,%2013_20_03.png</a>
            .<br>
            <br>
            No, he is not drunk... his MICE packets are corrupted by
            VK2ZEN-5 and<br>
            hence the gross track errors.<br>
            <br>
            My suggestion is to NOT use MIC encoding as there would seem
            little<br>
            chance of fixing network infrastructure.<br>
            <br>
            73<br>
            <span class="HOEnZb"><font color="#888888">Owen<br>
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