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--></style></head><body lang="EN-US" link="blue" vlink="purple"><div class="WordSection1"><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1f497d">It does not matter how you address it, even if a digi does not digipeat it, the channel is still busy during your packet period. And if any digi hears it at all, and digipeates it, then ALL the other digis are still blocked during that time too. So nothing is gained by limiting your packet to only be digipeated by one, since all will be blocked for the same two packet periods whether they digipeat it or not.</span></p><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1f497d"> </span></p><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1f497d">So APRS is designed to have all digieaters respond, and all respond at the same time, so that again, only the same two slots are used. So nothing is gained by targeting the first hop of a packet.</span></p><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1f497d"> </span></p><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1f497d">Conversely an order of magnitude is gained by targeting the 2<sup>nd</sup> hop (if any). Because then only the SECOND digi in the direction you choose is going to use up that 3<sup>rd</sup> slot time, instead of many.</span></p><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1f497d"> </span></p><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1f497d">This is why the DWAIT must be 0 in all APRS digis so they all transmit at the same time and do not wait for the others. That would drag out a single packet over multiple slots (not desired in APRS).</span></p><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1f497d"> </span></p><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1f497d">This built-in fratricide is intentional.</span></p><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1f497d"> </span></p><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1f497d">Little is lost, since anyone that is 10 dB closer to any one digi than all the rest will decode the packet no matter how many digis step on each other. Just the one that is 10 dB stronger to you will capture your FM receiver and will decode it.</span></p><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1f497d"> </span></p><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1f497d">Bob, WB4aPR<br><br></span></p><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1f497d"> </span></p><p class="MsoNormal"><b><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">From:</span></b><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"> <a href="mailto:jess@jesshaas.com">jess@jesshaas.com</a> [mailto:<a href="mailto:jess@jesshaas.com">jess@jesshaas.com</a>] <b>On Behalf Of </b>Jess Haas<br><b>Sent:</b> Monday, March 06, 2017 3:01 PM<br><b>To:</b> Robert Bruninga<br><b>Cc:</b> TAPR APRS Mailing List<br><b>Subject:</b> Re: [aprssig] Smart TX igate message routing?</span></p><p class="MsoNormal"> </p><div><p class="MsoNormal">Maybe it is a stupid idea but I do think we could do a bit better than a wide path. If we know a more specific path can't we decrease channel congestion and QRM while increasing range without needing any modification to the digipeater infrastructure?</p><div><p class="MsoNormal"> </p></div><div><p class="MsoNormal">Wouldn't the target station be more likely to receive the message if it is only hearing it from the closest digipeater instead of a bunch of them transmitting at the same time creating QRM?</p></div><div><p class="MsoNormal"> </p></div><div><p class="MsoNormal">When a mobile station is right next to an igate and they can hear each other directly why should we spam the whole region with the traffic via digipeaters?</p></div><div><p class="MsoNormal"> </p></div><div><p class="MsoNormal"><span style="font-size:9.5pt">Also it allows for using other stations not just digipeaters to extend your range for receiving messages not just transmitting. So if im in a valley and cant hit/hear a digipeater I can set the first hop in my path to another station i can hit and then when an igate tries to get a message back to me it will route it through that station.</span></p></div><div><p class="MsoNormal"> </p></div><div><p class="MsoNormal"><span style="font-size:9.5pt">-Jess</span></p></div><div><p class="MsoNormal"> </p></div><div><p class="MsoNormal"> </p><div><p class="MsoNormal">On Mon, Mar 6, 2017 at 10:11 AM, Robert Bruninga <<a href="mailto:bruninga@usna.edu" target="_blank">bruninga@usna.edu</a>> wrote:</p><blockquote style="border:none;border-left:solid #cccccc 1.0pt;padding:0in 0in 0in 6.0pt;margin-left:4.8pt;margin-right:0in"><div><div><p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1f497d">APRS by design will be digipeated by EVERY digipeater that hears it. So if the one farther south hears it, it is already going to digipeat it anyway. Nothing you need to do to make that happen… </span></p><p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1f497d"> </span></p><p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1f497d">And in SoCal, there are so many digis, that your path should be just one hop and it will still hit every digi that hears it that first hop.</span></p><p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1f497d"> </span></p><p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1f497d">Bob</span></p><p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1f497d"> </span></p><p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><b><span style="font-size:11.0pt;font-family:"Calibri",sans-serif">From:</span></b><span style="font-size:11.0pt;font-family:"Calibri",sans-serif"> aprssig [mailto:<a href="mailto:aprssig-bounces@tapr.org" target="_blank">aprssig-bounces@tapr.org</a>] <b>On Behalf Of </b>Jess Haas<br><b>Sent:</b> Monday, March 06, 2017 1:08 PM<br><b>To:</b> TAPR APRS Mailing List<br><b>Subject:</b> [aprssig] Smart TX igate message routing?</span></p><p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"> </p><div><p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto">Where I am located in Southern California I can hit many digipeaters. For home station beaconing setting a single one of them as my route seems to be the way to go but for tx message igating I was thinking it may make more sense if the outgoing path was the one that the station was last heard on. Has anyone implemented anything like this?</p><div><p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"> </p></div><div><p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto">For example the digipeater I have the strongest path to may not be able to get a message to a station farther south but I can hear and hit a digipeater rather far south that the station can hear easily. Also if I have heard a station directly recently than I should have no problem getting a message to them directly even if they have moved some with my basestation antenna and possibly higher power so digipeating to the whole area may be unnecessary.</p></div><div><p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"> </p></div><div><p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto">Another advantage of this would be that a station that is in an RF hole such as a valley that can't hear or hit a digipeater but has a path to another station that can could set that station as a path and messages would automatically be routed back to them.</p></div><div><p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"> </p></div><div><p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto">Thoughts?</p></div><div><p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"> Jess</p></div></div></div></div><p class="MsoNormal" style="margin-bottom:12.0pt"><br>_______________________________________________<br>aprssig mailing list<br><a href="mailto:aprssig@tapr.org">aprssig@tapr.org</a><br><a href="http://www.tapr.org/mailman/listinfo/aprssig" target="_blank">http://www.tapr.org/mailman/listinfo/aprssig</a></p></blockquote></div><p class="MsoNormal"> </p></div></div></div></body></html>