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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">I agree, there is no better tropo indicator (or meteorscatter) detection system than APRS. With 20,000 transmitters all over the country running continuously, even a few seconds of enhanced propogation will appear on the APRS network while the Voice Operators may be waiting72 hours for the weekend.</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">Of course, someone in a rural area that can only hear one local digi will hear a LOT more tropo than someone in a busy APRS area where the channel is always busy…</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">In fact, people is remote APRS areas my feel lonely with the lack of activity, but any activity they DO see can be very exciting with enhanced propogation… And now is the season for tropo. I hear it every day in Maryalnd in the mornings when I hear the FM radio stations all jumbled coming to work… bob</span></p><p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d"> </span></p><div><div style="border:none;border-top:solid #b5c4df 1.0pt;padding:3.0pt 0in 0in 0in"><p class="MsoNormal"><b><span style="font-size:10.0pt;font-family:"Tahoma","sans-serif"">From:</span></b><span style="font-size:10.0pt;font-family:"Tahoma","sans-serif""> aprssig [mailto:<a href="mailto:aprssig-bounces@tapr.org">aprssig-bounces@tapr.org</a>] <b>On Behalf Of </b>Ev Tupis via aprssig<br><b>Sent:</b> Tuesday, September 01, 2015 9:20 AM<br><b>To:</b> TAPR APRS Mailing List<br><b>Subject:</b> [aprssig] unusual Terrestrial APRS propagation</span></p></div></div><p class="MsoNormal"> </p><div><div id="yui_3_16_0_1_1441112402151_2858"><div id="yui_3_16_0_1_1441112402151_2857"><div id="yui_3_16_0_1_1441112402151_2856"><p class="MsoNormal" style="background:white"><b><span style="font-size:10.0pt;font-family:"Arial","sans-serif";color:black">Sent:</span></b><span style="font-size:10.0pt;font-family:"Arial","sans-serif";color:black"> Monday, August 31, 2015 8:47 PM<br><b id="yui_3_16_0_1_1441112402151_4042">Subject:</b> Re: [aprssig] unusual Terrestrial APRS propagation</span><span style="font-family:"Helvetica","sans-serif";color:black"></span></p></div><div id="yui_3_16_0_1_1441112402151_2867"><p class="MsoNormal" style="background:white"><span style="font-family:"Helvetica","sans-serif";color:black"> </span></p><div id="yiv0416169969"><div id="yui_3_16_0_1_1441112402151_2866"><div id="yui_3_16_0_1_1441112402151_2865"><div id="yui_3_16_0_1_1441112402151_2864"><div><p class="MsoNormal" style="margin-bottom:12.0pt;background:white"><span style="font-family:"Helvetica","sans-serif";color:black"> </span></p></div><div id="yiv0416169969yqtfd62827"><div id="yui_3_16_0_1_1441112402151_2863"><p class="MsoNormal" style="background:white"><span style="font-family:"Helvetica","sans-serif";color:black">On Mon, Aug 31, 2015 at 6:38 PM, Paul Bramscher via aprssig <<a href="mailto:aprssig@tapr.org" target="_blank">aprssig@tapr.org</a>> wrote:<br><br></span></p><p class="MsoNormal" style="background:white"><span style="font-family:"Helvetica","sans-serif";color:black">No errors in reasoning. I indeed heard 2m "DX" (Kansas and elsewhere to<br>Minnesota) -- but ONLY on 144.390 Mhz. If 2m was genuinely open to<br>tropo ducting, etc. it wouldn't manifest solely on that freq. This was<br>in the daytime over the weekend. If I truly had a 300-400 mile range on<br>2m, broadly speaking, there would have been many distant phone<br>conversations elsewhere on 2m. Instead, there were none at all.<br><br>Likely someone was just re-TX'ing internet traffic locally.</span></p><div id="yui_3_16_0_1_1441112402151_2868"><p class="MsoNormal" style="background:white"><span style="font-family:"Helvetica","sans-serif";color:black"> </span></p></div><p class="MsoNormal" style="background:white"><span style="font-family:"Helvetica","sans-serif";color:black">Hi Paul</span></p></div></div></div></div></div></div><div id="yui_3_16_0_1_1441112402151_3264"><p class="MsoNormal" style="background:white"><span style="font-family:"Helvetica","sans-serif";color:black">It is common for people to trust only their own observation. In this case, the lack of distant phone conversations on other frequencies is likely because there were no phone conversations taking place at the instant that you scanned for them.</span></p></div><div id="yui_3_16_0_1_1441112402151_3280"><p class="MsoNormal" style="background:white"><span style="font-family:"Helvetica","sans-serif";color:black"> </span></p></div><div id="yui_3_16_0_1_1441112402151_2974"><p class="MsoNormal" style="background:white"><span style="font-family:"Helvetica","sans-serif";color:black">What is being observed here is a classic tropospheric anomaly that occurs when a high pressure system sets up on the East Coast USA. The phenomenon has been documented and observed for decades. In fact, when it occurs over the Western Atlantic, it is referred to as a "Bermuda High" and hams that are East of the Appalachian Mountains benefit from it nicely.</span></p></div><div id="yui_3_16_0_1_1441112402151_2997"><p class="MsoNormal" style="background:white"><span style="font-family:"Helvetica","sans-serif";color:black"> </span></p></div><div id="yui_3_16_0_1_1441112402151_3013"><p class="MsoNormal" style="background:white"><span style="font-family:"Helvetica","sans-serif";color:black">The use of RF that is "always on" (APRS, WX Radar, etc) allows for easier visualization of the event.</span></p></div><div id="yui_3_16_0_1_1441112402151_3014"><p class="MsoNormal" style="background:white"><span style="font-family:"Helvetica","sans-serif";color:black"> </span></p></div><div id="yui_3_16_0_1_1441112402151_3076"><p class="MsoNormal" style="background:white"><span style="font-family:"Helvetica","sans-serif";color:black">I've attached three graphics to illustrate. They were just captured a moment ago and are...</span></p></div><div id="yui_3_16_0_1_1441112402151_3015"><p class="MsoNormal" style="background:white"><span style="font-family:"Helvetica","sans-serif";color:black"> </span></p></div><div id="yui_3_16_0_1_1441112402151_3031"><p class="MsoNormal" style="background:white"><span style="font-family:"Helvetica","sans-serif";color:black">Untitled00 = 144-MHz APRS-based propagation maps</span></p></div><div id="yui_3_16_0_1_1441112402151_3033"><p class="MsoNormal" style="background:white"><span style="font-family:"Helvetica","sans-serif";color:black">Untitled01 = 9-GHz NWS Radar propagation maps</span></p></div><div id="yui_3_16_0_1_1441112402151_3072"><p class="MsoNormal" style="background:white"><span style="font-family:"Helvetica","sans-serif";color:black">Untitled03 = NWS surface maps</span></p></div><div id="yui_3_16_0_1_1441112402151_3135"><p class="MsoNormal" style="background:white"><span style="font-family:"Helvetica","sans-serif";color:black"> </span></p></div><div id="yui_3_16_0_1_1441112402151_3817"><p class="MsoNormal" style="background:white"><span style="font-family:"Helvetica","sans-serif";color:black">The "geometry" of the inversion layer determines what frequencies it will affect.</span></p></div><div id="yui_3_16_0_1_1441112402151_3833"><p class="MsoNormal" style="background:white"><span style="font-family:"Helvetica","sans-serif";color:black"> </span></p></div><div id="yui_3_16_0_1_1441112402151_3136"><p class="MsoNormal" style="background:white"><span style="font-family:"Helvetica","sans-serif";color:black">By the way...see that "green patch" in the NWS map? That indicates a MASSIVE inversion in progress. If you were to scan for 10 GHz ham signals, you'd hear "ssssssssssssss" only because I doubt there are any QSO's taking place. :-)</span></p></div><div id="yui_3_16_0_1_1441112402151_3438"><p class="MsoNormal" style="background:white"><span style="font-family:"Helvetica","sans-serif";color:black"> </span></p></div><div id="yui_3_16_0_1_1441112402151_3440"><p class="MsoNormal" style="background:white"><span style="font-family:"Helvetica","sans-serif";color:black">'hope this is helpful.</span></p></div><div id="yui_3_16_0_1_1441112402151_3441"><p class="MsoNormal" style="background:white"><span style="font-family:"Helvetica","sans-serif";color:black"> </span></p></div><div id="yui_3_16_0_1_1441112402151_3442"><p class="MsoNormal" style="background:white"><span style="font-family:"Helvetica","sans-serif";color:black">Kind regards,</span></p></div><div id="yui_3_16_0_1_1441112402151_3443"><p class="MsoNormal" style="background:white"><span style="font-family:"Helvetica","sans-serif";color:black">Ev, W2EV</span></p></div><div id="yui_3_16_0_1_1441112402151_3444"><p class="MsoNormal" style="background:white"><span style="font-family:"Helvetica","sans-serif";color:black"> </span></p></div></div></div></div></div></div></body></html>