<html><head></head><body><div style="color:#000; background-color:#fff; font-family:Courier New, courier, monaco, monospace, sans-serif;font-size:16px"><div id="yui_3_16_0_ym19_1_1465816905815_3955"><span id="yui_3_16_0_ym19_1_1465816905815_4116">250 bytes per packet at undefined data rate? This seems like a low throughput IoT device.</span></div><div id="yui_3_16_0_ym19_1_1465816905815_3954" class="qtdSeparateBR"><br><br></div><div style="display: block;" id="yui_3_16_0_ym19_1_1465816905815_3936" class="yahoo_quoted">  <div id="yui_3_16_0_ym19_1_1465816905815_3935" style="font-family: Courier New, courier, monaco, monospace, sans-serif; font-size: 16px;"> <div id="yui_3_16_0_ym19_1_1465816905815_3934" style="font-family: HelveticaNeue, Helvetica Neue, Helvetica, Arial, Lucida Grande, sans-serif; font-size: 16px;"> <div id="yui_3_16_0_ym19_1_1465816905815_3951" dir="ltr"> <font id="yui_3_16_0_ym19_1_1465816905815_3952" face="Arial" size="2"> <hr id="yui_3_16_0_ym19_1_1465816905815_3953" size="1"> <b><span style="font-weight:bold;">From:</span></b> Andrew Rich via aprssig <aprssig@tapr.org><br> <b><span style="font-weight: bold;">To:</span></b> Ross Whenmouth <ross@topwire.co.nz>; TAPR APRS Mailing List <aprssig@tapr.org> <br> <b><span style="font-weight: bold;">Sent:</span></b> Monday, June 13, 2016 6:55 AM<br> <b><span style="font-weight: bold;">Subject:</span></b> Re: [aprssig] 9600 Baud Packet Network?<br> </font> </div> <div id="yui_3_16_0_ym19_1_1465816905815_3933" class="y_msg_container"><br><div id="yiv7651736922"><div id="yui_3_16_0_ym19_1_1465816905815_3932"><div id="yui_3_16_0_ym19_1_1465816905815_3931"><a id="yui_3_16_0_ym19_1_1465816905815_3950" rel="nofollow" shape="rect" target="_blank" href="http://www.lprs.co.uk/assets/media/downloads/eRIC_USB_Dongle.pdf">http://www.lprs.co.uk/assets/media/downloads/eRIC_USB_Dongle.pdf</a><br clear="none"><br clear="none"><div id="yui_3_16_0_ym19_1_1465816905815_3949">-----------------------------</div>Sent from my iPhone<div id="yui_3_16_0_ym19_1_1465816905815_3948">Andrew Rich</div><div id="yui_3_16_0_ym19_1_1465816905815_3947"><a rel="nofollow" shape="rect" ymailto="mailto:vk4tec@tech-software.net" target="_blank" href="mailto:vk4tec@tech-software.net">vk4tec@tech-software.net</a></div><div id="yui_3_16_0_ym19_1_1465816905815_3930"><a rel="nofollow" shape="rect" target="_blank" href="http://www.tech-software.net/">www.tech-software.net</a></div><div id="yui_3_16_0_ym19_1_1465816905815_3937">0419 738 223</div></div><div class="yiv7651736922yqt9874252510" id="yiv7651736922yqt38690"><div id="yui_3_16_0_ym19_1_1465816905815_4152"><br clear="none">On 13 Jun 2016, at 19:20, Ross Whenmouth via aprssig <<a rel="nofollow" shape="rect" ymailto="mailto:aprssig@tapr.org" target="_blank" href="mailto:aprssig@tapr.org">aprssig@tapr.org</a>> wrote:<br clear="none"><br clear="none"></div><blockquote type="cite"><div>
  
    </div></blockquote></div></div><div class="yiv7651736922yqt9874252510" id="yiv7651736922yqt64068"><div id="yui_3_16_0_ym19_1_1465816905815_4126"><div id="yui_3_16_0_ym19_1_1465816905815_4125" class="yiv7651736922moz-cite-prefix">Hi,<br clear="none">
      <br clear="none">
      Robert Bruninga wrote;<br clear="none">
      <blockquote id="yui_3_16_0_ym19_1_1465816905815_4151" type="cite"><span style="font-size:11.0pt;">19k2
          is there – the modules are $40</span></blockquote>
      Bob, could you please post a link to these modules?<br clear="none">
      <br clear="none">
      <br clear="none">
      Re: faster than 9k6 without modifying radios<br clear="none">
      At the penalty of increased sensitivity to noise, modulations more
      complex than K9NG/G3RUH can be fed through the <u>linear</u><u>
        audio channel</u> of a pair of 9k6-ready ham transceivers. A 9k6
      audio channel provides 5 kHz bandwidth, more than that of a
      standard telephone land-line - a quick back of the envelope with
      Shanon's Law indicates that we should be able to push bits much
      faster than 9k6 <a rel="nofollow" shape="rect" target="_blank" href="https://en.wikipedia.org/wiki/Shannon%E2%80%93Hartley_theorem"></a><a rel="nofollow" shape="rect" class="yiv7651736922moz-txt-link-freetext" target="_blank" href="https://en.wikipedia.org/wiki/Shannon%E2%80%93Hartley_theorem">https://en.wikipedia.org/wiki/Shannon%E2%80%93Hartley_theorem</a><br clear="none">
      Think DSP "TNC" software running in your PC, smartphone, Raspberry
      pi, or in a processor like a PIC32 or STM32, with automatic
      channel equalisation, GMSK/QPSK/n-QAM and Forward Error
      Correction. Note that about twenty years ago you could just go to
      the computer store and buy a consumer modem that would push 33k6
      in 3.4 kHz BW down a (then) 40 year old telephone line...<br clear="none">
      <br clear="none">
      <br clear="none">
      Re: Utilising smartphones, tablets, laptops, etc as user
      interfaces;<br clear="none">
      Why not use Bluetooth to link your device to the TNC? - it is
      pretty much well universally supported by mobile devices and
      doesn't chew through as much battery power as WiFi<br clear="none">
      eg <a rel="nofollow" shape="rect" target="_blank" href="http://www.mobilinkd.com/tnc2/">http://www.mobilinkd.com/tnc2/</a><br clear="none">
      <br clear="none">
      <br clear="none">
      Re: Transferring (larger) files;<br clear="none">
      Send larger packets so there is less time consumed per unit
      payload on TXdelay, ACK, etc. eg a 1500 byte/12kbit packet takes
      less than 1.5 seconds to send at 9k6, and only incurs one TXdelay,
      where as, if you limit yourself to 256 byte AX.25 packets, you
      need to send 6 of them to move 1500 bytes... <br clear="none">
      Forward Error Correction seems like a good way to reduce packet
      re-transmissions (corruption of a single bit in standard AX.25
      results in rejection of the packet, requiring a resend) <a rel="nofollow" shape="rect" target="_blank" href="http://www.stensat.org/docs/FX-25_01_06.pdf"></a><a rel="nofollow" shape="rect" class="yiv7651736922moz-txt-link-freetext" target="_blank" href="http://www.stensat.org/docs/FX-25_01_06.pdf">http://www.stensat.org/docs/FX-25_01_06.pdf</a><br clear="none">
      New data transfer protocols eg using a "Fountain Code" would allow
      most of the ACK/REJ packets to be eliminated and would be very
      efficient for simultaneously distributing a file to multiple
      recipients <a rel="nofollow" shape="rect" target="_blank" href="https://docs.switzernet.com/people/emin-gabrielyan/060112-capillary-references/ref/MacKay05.pdf"></a><a rel="nofollow" shape="rect" class="yiv7651736922moz-txt-link-freetext" target="_blank" href="https://docs.switzernet.com/people/emin-gabrielyan/060112-capillary-references/ref/MacKay05.pdf">https://docs.switzernet.com/people/emin-gabrielyan/060112-capillary-references/ref/MacKay05.pdf</a><br clear="none">
      <br clear="none">
      <br clear="none">
      73 ZL2WRW<br clear="none">
      Ross Whenmouth<br clear="none">
    </div>
  

<blockquote type="cite"><div><span>_______________________________________________</span><br clear="none"><span>aprssig mailing list</span><br clear="none"><span><a rel="nofollow" shape="rect" ymailto="mailto:aprssig@tapr.org" target="_blank" href="mailto:aprssig@tapr.org">aprssig@tapr.org</a></span><br clear="none"><span><a rel="nofollow" shape="rect" target="_blank" href="http://www.tapr.org/mailman/listinfo/aprssig">http://www.tapr.org/mailman/listinfo/aprssig</a></span><br clear="none"></div></blockquote></div></div></div><br><div class="yqt9874252510" id="yqt60411">_______________________________________________<br clear="none">aprssig mailing list<br clear="none"><a shape="rect" ymailto="mailto:aprssig@tapr.org" href="mailto:aprssig@tapr.org">aprssig@tapr.org</a><br clear="none"><a shape="rect" href="http://www.tapr.org/mailman/listinfo/aprssig" target="_blank">http://www.tapr.org/mailman/listinfo/aprssig</a><br clear="none"></div><br><br></div> </div> </div>  </div></div></body></html>