[aprssig] The East will Rise again! (at 9600?)

Scott Miller scott at opentrac.org
Thu May 5 13:35:18 CDT 2016


If we're going to push for expanded 9600 baud implementation, can we 
pretty please enforce some more rigorous technical standards than on 
144.39?  For 1200 baud APRS you never know if you're going to see Bell 
202 or V.23, pre-emphasized or flat, deviation could be anything, the 
HDLC reset sequence is awful for fast clock recovery but there's no 
other standard preamble, you don't know if the receiving TNC is going to 
choke on non-printable characters in the payload or if it's even 
checking FCS or PID, and you've got tens of thousands of Kenwood devices 
that have a fixed 500 ms TXD.

At 9600 baud there doesn't seem to be much agreement on filter selection 
and documentation is scarce.

You could probably match 1200 baud's Eb/N0 advantage just by requiring 
certain basic technical standards on a 9600 baud network.

Scott
N1VG

On 5/5/2016 10:59 AM, Brian D Heaton via aprssig wrote:
> Why KPC9612s and 2M?
>
> Commercial TNC/Node combos (KPC9612 and others) - Small computers are 
> available which can provide all the needed/desired functions and 
> interface to multiple TNCs or sound interfaces. Recent testing shows 
> that QPSK/4800 is quite reliable via a sound interface to a radio with 
> a 9600 data port. 9600 is just a step up the chain from that. I expect 
> xPSK (likely OQPSK or 8PSK) rates of around 19200 are quite 
> achievable. You can still use KPC9612s if sticking to 9600.
>
> Many (I will guess "the vast majority") of EOCs already have issues 
> with desense from multiple radios on 2M. If the supporting rationale 
> that may make more sites available is EMCOMM support, I would put the 
> backbone links on either 1.25M or 70cm with a preference for 1.25M. I 
> would keep the backbone frequency clear of users to avoid additional 
> congestion and hidden transmitters. Users could access on 
> 2M/1.25M/70cm (whichever band the backbone link(s) aren't running on) 
> at either 1200 or 9600. Why kill performance of an engineered and well 
> adjusted backbone link/network with user stations?
>
> 73-KY9K/Brian
>
>
> On 5/5/2016 10:29, Robert Bruninga via aprssig wrote:
>>
>> SAVE your KPC9612’s Boys, the East will RISE AGAIN!
>>
>> The Golden Packet team is toying with the idea of making our annual 
>> Appalachian mountain digipeater string from Maine to Georgia 
>> permament and making it a 9600 baud network for emergency and ham 
>> radio disaster response and play.  We already have 3 of the 14 sites 
>> with approval for installations…
>>
>> Lets face it, traditional packet networks are deadandalthough APRS is 
>> alive and well, it is specific andonly operates at 1200 baud.Although 
>> all fully integrated APRS radios work perfectly well at 1200 and 9600 
>> baud, all of the existing APRS network is 1200because all the 
>> digipeaters (not integrated APRS radios) operate at 1200 and the 
>> majority of all home APRS stationsand IGatesuse TNC’sthat operateat 
>> 1200. A huge legacy.  Besides, going to 9600 only barely doubles APRS 
>> speeds while degrading link reliability.
>>
>> So, since we have already shown for 6 years now, that this long 2000 
>> mile linear chain of mountains and valleys can support a 2000 mile 
>> network with only 14 digis,  why not establish a long haul 9600 baud 
>> Node chainfrom Maine to Georgiawhich could be a significant boost to 
>> Packet radio emergency operations. The network would not operate as 
>> APRS digipeaters but as KAnodes.  As we all knew back in the 1990’s 
>> link-by-link acknowledgment was vastly superior to end-to-end.
>>
>> We already have three sites in MD, and PA …  But we need more than 
>> hikers, to get us access to some existing ham radio maintained 
>> sites.  We do NOT want nodes to branch off down into the plains.  
>> These nodes would bog down the network. No, the main backbone would 
>> be to support emergency operations with beams that can point up to 
>> the mountains to pass traffic.
>>
>> So, we are splashing this onto the APRSSIG to see if people have SITE 
>> access and/or have unused 9600 baud KPC-9612’s to step up and lets 
>> see what we got.  Also will need a freq.  I’m thinking 145.01 but 
>> every time I think of it, people give feedback, and I LOSE or forget 
>> the feedback as to what existing systems are already on 145.01, such 
>> as DX clusters, etc…
>>
>> Every day we get MORE AND MORE addicted to our wireless 
>> infrastructure, which we all know, will be hard to access in a real 
>> emergency.  We need to keep the Ham radio Plan-B alive…
>>
>> Bob, WB4APR
>>
>>
>>
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