<html><head><meta http-equiv="content-type" content="text/html; charset=utf-8"></head><body dir="auto">OpenTrac is an even better idea and more extensible and more easily processed than APRS packets! Let’s really take a moment to reflect on what it could mean to start with a better solution end to end!<div><br></div><div>Gregg<br><br><div dir="ltr">Sent from my iPhone</div><div dir="ltr"><br><blockquote type="cite">On Feb 13, 2022, at 6:32 PM, John Langner WB2OSZ <wb2osz@comcast.net> wrote:<br><br></blockquote></div><blockquote type="cite"><div dir="ltr"><meta http-equiv="Content-Type" content="text/html; charset=us-ascii"><meta name="Generator" content="Microsoft Word 14 (filtered medium)"><style><!--
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</o:shapelayout></xml><![endif]--><div class="WordSection1"><p class="MsoNormal"><o:p> </o:p></p><p class="MsoNormal">The AX.25 and APRS protocol specifications say nothing<o:p></o:p></p><p class="MsoNormal"> at all about modems.<o:p></o:p></p><p class="MsoNormal"><o:p> </o:p></p><p class="MsoNormal">The reason that we are using 1200 bps is because early <o:p></o:p></p><p class="MsoNormal">packet radio developers, in Canada, in the late 1970s, happened <o:p></o:p></p><p class="MsoNormal">to acquire a pile of old Bell 202 modems for 75 cents each.<o:p></o:p></p><p class="MsoNormal"><o:p> </o:p></p><p class="MsoNormal">The method that we use for 9600 bps was developed in<o:p></o:p></p><p class="MsoNormal">the late 1980s. It has been widely implemented but won't<o:p></o:p></p><p class="MsoNormal">work with the microphone and speaker connections because<o:p></o:p></p><p class="MsoNormal">the audio processing distorts the signal and limits the bandwidth.<o:p></o:p></p><p class="MsoNormal"><o:p> </o:p></p><p class="MsoNormal">In the early 1990s, multiple TNC vendors produced products capable<o:p></o:p></p><p class="MsoNormal">of 2400 bps: MFJ-2400, AEA PK232-2400, Kantronics KPC-2400.<o:p></o:p></p><p class="MsoNormal">Maybe if other vendors had offered the same we would all be using<o:p></o:p></p><p class="MsoNormal">2400 bps today.<o:p></o:p></p><p class="MsoNormal"><o:p> </o:p></p><p class="MsoNormal">With the shift from hardware modems to software modems,<o:p></o:p></p><p class="MsoNormal">the possibilities are endless. Upgrades are easy. <o:p></o:p></p><p class="MsoNormal"><o:p> </o:p></p><p class="MsoNormal"><o:p> </o:p></p><p class="MsoNormal">Two methods of Forward Error Correction are currently being used:<o:p></o:p></p><p class="MsoListParagraph" style="text-indent:-.25in;mso-list:l0 level1 lfo1"><!--[if !supportLists]--><span style="mso-list:Ignore">(1)<span style="font:7.0pt "Times New Roman""> </span></span><!--[endif]-->FX.25 which is completely interoperable with original AX.25.<o:p></o:p></p><p class="MsoListParagraph" style="text-indent:-.25in;mso-list:l0 level1 lfo1"><!--[if !supportLists]--><span style="mso-list:Ignore">(2)<span style="font:7.0pt "Times New Roman""> </span></span><!--[endif]-->IL2P which has less overhead but is not compatible.<o:p></o:p></p><p class="MsoNormal"><o:p> </o:p></p><p class="MsoNormal"><o:p> </o:p></p><p class="MsoNormal">Better alternatives are available today for those who want to use <o:p></o:p></p><p class="MsoNormal">them. The problem is trying to convince most of the installed base<o:p></o:p></p><p class="MsoNormal">to break free of a precedent set more than 40 years ago.<o:p></o:p></p><p class="MsoNormal"><o:p> </o:p></p><p class="MsoNormal">73,<o:p></o:p></p><p class="MsoNormal">John WB2OSZ<o:p></o:p></p><p class="MsoNormal"><o:p> </o:p></p></div><span>_______________________________________________</span><br><span>aprssig mailing list</span><br><span>aprssig@lists.tapr.org</span><br><span>http://lists.tapr.org/mailman/listinfo/aprssig_lists.tapr.org</span><br></div></blockquote></div></body></html>