<div dir="ltr">Andrew,<div><br></div><div>You're going to find that only Government agencies and the Military are granted the luxury of such practice. In the commercial world where time is actually money, such practices are loosely followed largely by Graduates until such time as they realise they can work with out it. At which point we make then senior.</div><div><br></div><div>73</div><div><br></div><div>Matthew</div><div>VK5ZM</div></div><div class="gmail_extra"><br><div class="gmail_quote">On 18 December 2017 at 14:31, Andrew Rich <span dir="ltr"><<a href="mailto:vk4tec@tech-software.net" target="_blank">vk4tec@tech-software.net</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">Are we following any system engineering practices ?<br>
<br>
Sent from my iPhone<br>
<span class=""><br>
> On 18 Dec 2017, at 1:17 pm, Glen English VK1XX <<a href="mailto:glenlist@pacificmedia.com.au">glenlist@pacificmedia.com.au</a>> wrote:<br>
><br>
> Yep<br>
><br>
</span>> It's ready to go. But I have to get work done this week, got to sgo to sort a few things out at a few sites. I need to get some python code written before going to site tomorrow.<br>
<div class="HOEnZb"><div class="h5">><br>
> Over the weekend I remembered how it all works (it's a modem I wrote 4 years ago) , and modified a few blocks to reduce the CPU usage for this narrow band application, and also I added a block to generate IQ baseband signals from real input (radio output) , so it can use a standard radio.<br>
><br>
> Compilation targets are x86 and ARM+NEON... If compiling for ARM, it is HEAVILY NEON optimized as it had to run on a certain platform ... (oDroid) .<br>
><br>
> It searches through a specified bandwidth, throwing as many cores at it as you tell it to, each core gets a chunk of spectrum to work on. Roughly 50mS per second processing time per 2kHz of searching BW on a 3.5 GHz i4670k single thread. Will run on a Odroid C1, C2, XU4 etc. might run on later Pis, never used them...<br>
><br>
> Sync can be acheived at about 9dB below what is required for a decode (~ 1dB SNR), the modem can decode multiple transissions simultaneously in the passband and used a 1/5 rate LDPC code. Modulation is D2BPSK (2nd order diff ).<br>
><br>
> g<br>
><br>
>> On 18/12/2017 1:30 PM, Graeme wrote:<br>
>> Glen English has stated that he is working on something new for HF APRS that should be a lot better than what’s currently available.<br>
>> Graeme 2HFG<br>
>> *From:* Gerard Hill<br>
>> *Sent:* Monday, December 18, 2017 11:25 AM<br>
>> *To:* Australian APRS Users<br>
>> *Subject:* Re: [OZAPRS] HF APRS<br>
>> PAs - as in Power Amplifiers, Andrew.<br>
>> In the past I've run an IGate using PSK63 and GFSK63 using software called APRS Messenger <<a href="http://www.crosscountrywireless.net/aprs_messenger.htm" rel="noreferrer" target="_blank">http://www.<wbr>crosscountrywireless.net/aprs_<wbr>messenger.htm</a>>.<br>
>> These modes have great performance even without Forward Error Correction.<br>
>> Availability for mobiles is limited although there is a standalone modem for PSK63 available called FreeTrak63 <<a href="http://www.ringolake.com/pic_proj/FT63/ft63_page.html" rel="noreferrer" target="_blank">http://www.ringolake.com/pic_<wbr>proj/FT63/ft63_page.html</a>>.<br>
>> Some info on these modes from WA8LMF here <<a href="http://wa8lmf.net/APRS_PSK63/index.htm" rel="noreferrer" target="_blank">http://wa8lmf.net/APRS_PSK63/<wbr>index.htm</a>>.<br>
>> Be interesting to know more about what Matthew is referring to.<br>
>> Cheers,<br>
>> Gerard - VK2IO<br>
>> On 18 December 2017 at 11:01, <<a href="mailto:vk4tec@tech-software.net">vk4tec@tech-software.net</a>> wrote:<br>
>><br>
>> What is “Pas”<br>
>><br>
>> Whats coming ?<br>
>><br>
>> *From:*OZAPRS [mailto:<a href="mailto:ozaprs-bounces@aprs.net.au">ozaprs-bounces@aprs.<wbr>net.au</a>] *On Behalf Of<br>
>> *Matthew Cook<br>
>> *Sent:* Monday, 18 December 2017 9:22 AM<br>
>> *To:* Australian APRS Users <<a href="mailto:ozaprs@aprs.net.au">ozaprs@aprs.net.au</a>><br>
>> *Subject:* Re: [OZAPRS] HF APRS<br>
>><br>
>> I'd wait until early next year and see what's coming in terms of<br>
>> HF ARRS, plans are a foot.<br>
>><br>
>> 73<br>
>><br>
>> Matthew<br>
>><br>
>> VK5ZM<br>
>><br>
>> On 18 December 2017 at 09:48, Robert <<a href="mailto:rbaker@bigpond.com">rbaker@bigpond.com</a>> wrote:<br>
>><br>
>> Hi All.<br>
>><br>
>> Just a quick question on HF APRS.<br>
>><br>
>> I have seen people chatting about modified FSK modem used<br>
>> directly onto Pas. My question is do I use these modified<br>
>> modems when I directly use say IC-706 mk2, or will a TT4,<br>
>> Opentracker do the job.<br>
>><br>
>> Thanks in advance.<br>
>><br>
>> Cheers<br>
>><br>
>> Robert<br>
>><br>
>><br>
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>> <<a href="http://lists.aprs.net.au/mailman/listinfo/ozaprs" rel="noreferrer" target="_blank">http://lists.aprs.net.au/<wbr>mailman/listinfo/ozaprs</a>><br>
>><br>
>><br>
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>> <<a href="http://lists.aprs.net.au/mailman/listinfo/ozaprs" rel="noreferrer" target="_blank">http://lists.aprs.net.au/<wbr>mailman/listinfo/ozaprs</a>><br>
>><br>
>> ------------------------------<wbr>------------------------------<wbr>------------<br>
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>><br>
>><br>
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><br>
><br>
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> <a href="mailto:OZAPRS@aprs.net.au">OZAPRS@aprs.net.au</a><br>
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</div></div></blockquote></div><br></div>