<html><head></head><body><div style="color:#000; background-color:#fff; font-family:Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif;font-size:16px"><div id="yui_3_16_0_1_1470660160766_20664" dir="ltr"><span id="yui_3_16_0_1_1470660160766_20718">I remember years ago my buddy FD K4FDS and I noting that his D700 always needed full-quieting packet audio to decode. Back then, we were routinely putting a D700 up against the HamHUD/KPC-3 setup we both owned and the KPC-3 always blew the D700 out of the water on decode performance. I have noticed that the D710 seems to have a better decode rate with less than perfect packets. I guess that has a lot to do with them moving away from the Tassco modem and going to a DSP decoding method. Much like what we're now doing in the YagTracker and ExpressTracker. They use SI3000 codec chips to do all of the audio handling. Remi has done a phenominal job making that little $3 codec do the job of a $10 dedicated AFSK modem chip.</span></div><div></div><div id="yui_3_16_0_1_1470660160766_20665"> </div><div class="signature" id="yui_3_16_0_1_1470660160766_20831">Jason Rausch - KE4NYV</div><div class="signature" id="yui_3_16_0_1_1470660160766_20831">RPC Electronics, LLC<br><div id="yui_3_16_0_1_1470660160766_20830"><a href="http://www.rpc-electronics.com/" id="yui_3_16_0_1_1470660160766_20828">www.rpc-electronics.com</a></div><div id="yui_3_16_0_1_1470660160766_20830"><br></div></div><div class="qtdSeparateBR" id="yui_3_16_0_1_1470660160766_20836"><br><br></div><div class="yahoo_quoted" id="yui_3_16_0_1_1470660160766_20840" style="display: block;"> <div style="font-family: Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif; font-size: 16px;" id="yui_3_16_0_1_1470660160766_20839"> <div style="font-family: HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif; font-size: 16px;" id="yui_3_16_0_1_1470660160766_20838"> <div dir="ltr" id="yui_3_16_0_1_1470660160766_20837"> <font size="2" face="Arial" id="yui_3_16_0_1_1470660160766_20841"> <hr size="1"> <b><span style="font-weight:bold;">From:</span></b> Stephen H. Smith via aprssig <aprssig@tapr.org><br> <b><span style="font-weight: bold;">To:</span></b> TAPR APRS Mailing List <aprssig@tapr.org> <br> <b><span style="font-weight: bold;">Sent:</span></b> Friday, August 5, 2016 11:53 PM<br> <b><span style="font-weight: bold;">Subject:</span></b> [aprssig] Kenwood D700 Internal TNC Amazingly Mediocre!<br> </font> </div> <div class="y_msg_container" id="yui_3_16_0_1_1470660160766_20842"><br>I had always assumed that the built-in TNC of the D700 was fairly optimized, <br>due to being mated directly to the radio's discriminator, avoiding audio <br>channel distortion, audio level issues, squelch rise times, de-emphasis issues, <br>etc.<br><br>I just got back from a road trip to the Colorado Rockies for the annual <br>Evergreen Jazz Festival. While there, I did some coverage testing in the <br>mountains around Evergreen of a potential portable digipeater and tracker for <br>the festival shuttle bus, that may be used next year.<br><br>This is very rugged mountain terrain with few line-of-sight paths and lots of <br>multipath. I used the D700's internal TNC with one copy of UIview on my <br>Panasonic CF-51 mobile Toughbook.<br><br>I also connected the 6-pin mini-DIN "data port" of the D700 through one of my <br>homebrew sound card interfaces to a Behringer UCA-202 external USB "soundcard". <br>In turn, the UCA-202 was used by the UZ7HO Soundmodem software TNC. The <br>Soundmodem was linked to a second copy of UIview running on the same computer. <br>(The Soundmodem faithfully emulates the AGW Packet Engine interface supported <br>by most current APRS clients.)<br><br>The tests consisted of placing my FT-1500/TinyTrack 3 ammo-box tracker at the <br>hillside location I picked for the digipeater, based on radials I drew on <br>Delorme TopoUSA. The tracker was set to beacon every 20 seconds on 144.37 MHz. <br>I then drove the 4-mile loop route taken by the shuttle bus during the event.<br><br>[The original intent of using the soft TNC on the mini-DIN port at all was to <br>try using 300-baud HF-style packet on VHF/FM to gain 3-4 dB of noise margin <br>compared to 1200 baud.]<br><br>I was completely shocked at the difference between the D700's hardware TNC and <br>the software TNC, both at 1200 baud. When the signals were clean and <br>fully-quieted, there was essentially no difference between the two TNCs. When <br>the signals fell out of full quieting, or were "fuzzed up" with multipath <br>distortion, the Soundmodem massively outperformed the D700 internal TNC.<br><br>Driving the 4-mile winding loop around Evergreen, only about a third of the <br>loop showed on the D700 hardware TNC, while 100% of the beacon transmissions <br>showed on the instance of UIview linked to the Soundmodem soft TNC.<br><br>When I saw how well the Soundmodem worked at 1200 baud, I abandoned the idea of <br>going to 300 baud for this project. (Staying at 1200 means I can intermix <br>off-the-shelf 1200-baud TNCs, radios and soft TNCs, while 300 baud would <br>require that every node involve a PC of some sort running the 300-baud software <br>Soundmodem.)<br><br>____________________________________________________________________<br><br> Stephen H. Smith wa8lmf (at) aol.com<br>Skype: WA8LMF<br>EchoLink: Node # 14400 [Think bottom of the 2-meter band]<br>Home Page: <a href="http://wa8lmf.net/" target="_blank">http://wa8lmf.net</a><br><br> _______ Windows 10 Outrages! _______<br> <<a href="http://wa8lmf.net/Windows10_Info" target="_blank">http://WA8LMF.net/Windows10_Info</a>><br><br>Live Off-The-Air APRS Activity Maps<br> <<a href="http://wa8lmf.net/map" target="_blank">http://wa8lmf.net/map</a>><br><br>Long-Range APRS on 30 Meters HF<br> <<a href="http://wa8lmf.net/aprs/HF_APRS_Notes.htm" target="_blank">http://wa8lmf.net/aprs/HF_APRS_Notes.htm</a>><br><br><br>_______________________________________________<br>aprssig mailing list<br><a ymailto="mailto:aprssig@tapr.org" 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><br><br><br></div> </div> </div> </div></div></body></html>