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<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>http://tech-software.net/wordpress/wp-content/uploads/2016/05/img_2645.jpg<o:p></o:p></span></font></p>
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<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>Add AMP and your are laughing<o:p></o:p></span></font></p>
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<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>Mr Andrew Rich</span></font><font
color=navy><span style='color:navy'><o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
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<p class=MsoNormal><font size=2 color=navy face=Arial><span style='font-size:
10.0pt;font-family:Arial;color:navy'>0419 738 223</span></font><o:p></o:p></p>
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<p class=MsoNormal><b><font size=2 face=Tahoma><span lang=EN-US
style='font-size:10.0pt;font-family:Tahoma;font-weight:bold'>From:</span></font></b><font
size=2 face=Tahoma><span lang=EN-US style='font-size:10.0pt;font-family:Tahoma'>
aprssig [mailto:aprssig-bounces@tapr.org] <b><span style='font-weight:bold'>On
Behalf Of </span></b>Andrew Rich via aprssig<br>
<b><span style='font-weight:bold'>Sent:</span></b> Monday, 13 June 2016 8:55 PM<br>
<b><span style='font-weight:bold'>To:</span></b> Ross Whenmouth; TAPR APRS
Mailing List<br>
<b><span style='font-weight:bold'>Subject:</span></b> Re: [aprssig] 9600 Baud
Packet Network?</span></font><span lang=EN-US><o:p></o:p></span></p>
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12.0pt'><o:p> </o:p></span></font></p>
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<p class=MsoNormal style='margin-bottom:12.0pt'><font size=3
face="Times New Roman"><span style='font-size:12.0pt'><a
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><o:p></o:p></span></font></p>
<div>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'>-----------------------------<o:p></o:p></span></font></p>
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<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'>Sent from my iPhone<o:p></o:p></span></font></p>
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<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'>Andrew Rich<o:p></o:p></span></font></p>
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<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'><a href="mailto:vk4tec@tech-software.net">vk4tec@tech-software.net</a><o:p></o:p></span></font></p>
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12.0pt'><a href="http://www.tech-software.net">www.tech-software.net</a><o:p></o:p></span></font></p>
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<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'>0419 738 223<o:p></o:p></span></font></p>
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<p class=MsoNormal style='margin-bottom:12.0pt'><font size=3
face="Times New Roman"><span style='font-size:12.0pt'><br>
On 13 Jun 2016, at 19:20, Ross Whenmouth via aprssig <<a
href="mailto:aprssig@tapr.org">aprssig@tapr.org</a>> wrote:<o:p></o:p></span></font></p>
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<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'>Hi,<br>
<br>
Robert Bruninga wrote;<br>
<br>
<o:p></o:p></span></font></p>
<p class=MsoNormal><font size=2 face=Calibri><span style='font-size:11.0pt;
font-family:Calibri'>19k2 is there – the modules are $40</span></font><o:p></o:p></p>
<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'>Bob, could you please post a link to these modules?<br>
<br>
<br>
Re: faster than 9k6 without modifying radios<br>
At the penalty of increased sensitivity to noise, modulations more complex than
K9NG/G3RUH can be fed through the <u>linear 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 href="https://en.wikipedia.org/wiki/Shannon%E2%80%93Hartley_theorem"></a><a
href="https://en.wikipedia.org/wiki/Shannon%E2%80%93Hartley_theorem">https://en.wikipedia.org/wiki/Shannon%E2%80%93Hartley_theorem</a><br>
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>
<br>
<br>
Re: Utilising smartphones, tablets, laptops, etc as user interfaces;<br>
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>
eg <a href="http://www.mobilinkd.com/tnc2/">http://www.mobilinkd.com/tnc2/</a><br>
<br>
<br>
Re: Transferring (larger) files;<br>
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>
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
href="http://www.stensat.org/docs/FX-25_01_06.pdf"></a><a
href="http://www.stensat.org/docs/FX-25_01_06.pdf">http://www.stensat.org/docs/FX-25_01_06.pdf</a><br>
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
href="https://docs.switzernet.com/people/emin-gabrielyan/060112-capillary-references/ref/MacKay05.pdf"></a><a
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>
<br>
<br>
73 ZL2WRW<br>
Ross Whenmouth<o:p></o:p></span></font></p>
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<p class=MsoNormal><font size=3 face="Times New Roman"><span style='font-size:
12.0pt'>_______________________________________________<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">http://www.tapr.org/mailman/listinfo/aprssig</a><o:p></o:p></span></font></p>
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