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[aprssig] KJ4GQV ClusterBalloon Flying

Bob Bruninga bruninga at usna.edu
Sun Aug 1 14:59:22 UTC 2010

Thanks for the reminder!  I have remembered that someone else suggested the WIDE1-1 idea which I jumped on immediatley as the solution to the RELAY problem.  But over the years I could not remember who had posted that original email.  So now that we know it was you, I'll try to remember this and weave it into my docs when I get the chance.


---- Original message ----
>Date: Sat, 31 Jul 2010 16:16:27 -0700
>From: aprssig-bounces at tapr.org (on behalf of "Stephen H. Smith" <wa8lmf2 at aol.com>)
>Subject: Re: [aprssig] KJ4GQV ClusterBalloon Flying  
>To: TAPR APRS Mailing List <aprssig at tapr.org>,oh2mqk at sral.fi
>   On 7/31/2010 12:45 PM, Matti Aarnio wrote:
> What?  Is my APRS digipeater code wrong as it treats all  WIDEn-N
> constructs the same and does dupe suppression on them all?
>   Under the current "New Paradigm" standards,
>   WIDE1-1   IS   treated differently from higher
>   orders of N-N
>   The whole WIDE1-1, WIDE2-1 construct was invented
>   (it was my proposal years ago) to work around the
>   "brain-dead" firmware limitations in Kantronics KPC3
>   TNCs. These TNCs are by far the most widely-used
>   piece of hardware for stand-alone digis without a
>   computer in the US.   [It's hard to beat the
>   simplicity and low power consumption (15mA at 12
>   VDC) of a KPC3+radio digi at a remote site.]    The
>   problem is that KPCs do dupe suppression on WIDEn-N
>   paths but NOT on plain  RELAY or plain WIDE.    
>   On the other hand, many home users operating
>   first-tier low-level digipeaters (that in the past
>   responded to "RELAY") use old TNCs (such as PK-232s,
>   TAPR TNC-2s, MFJ 1270s, etc) that do not have
>   APRS-aware firmware in them.  These older devices
>   CAN NOT do   n-N   decremented SSIDs.    
>   With rapid APRS growth in the early '2000s, the
>   volume of unnecessary APRS traffic due to RELAY and
>   plain WIDE not supporting dupe checking just
>   exploded.    A lot of discussion followed on how one
>   could migrate to an exclusively WIDEn-N network
>   (with effective dupe control)  while still allowing 
>   non-N-N-aware   home fill-in digis to remain part of
>   the APRS infrastructure.  At the same time, one
>   wanted to prevent home digis from acting on anything
>   but the very first hop of a path.   
>   The solution was the two-part  WIDE1-1,WIDE2-n path
>   I proposed.  
>   All home low-level digis set WIDE1-1 as a simple
>   alias to be treated as an ordinary callsign of WIDE1
>   with an SSID of -1.   When a "dumb" home digi hears
>   WIDE1-1 as the first hop in a path, it digipeats it
>   just like any other fixed callsign, marks it as
>   used, and passes the second WIDE2-1 or WIDE2-2 part
>   onward to the next tier of "real" N-N digis.    (The
>   home digis completely ignore WIDE2-anything or
>   higher since only WIDE1-1 is set as an alias to
>   digipeat on.)
>   True high-level WIDEn-N will respond to any value of
>   WIDEn.  If a high-level digi (that DOES have proper
>   WIDEn-N support) happens to hear the initial
>   transmission, it will process WIDE1-1 as a
>   decremented n-N, mark it used up and hand the second
>   half WIDE2-n to the next (high-level)
>   digipeater(s). 
>   The difference when monitored off the air after the
>   first hop is that a home fill-in digipeat of the
>   first hop would yield
>        WA8LMF to APRS via  WIDE1-1*,WIDE2-1
>   while a first hop captured by a "real" decrementing
>   WIDEn-N digi, would produce
>        WA8LMF to APRS via WIDE1-0*,WIDE2-1  
>                 or possibly
>        WA8LMF to APRS via *WIDE1*,WIDE2-1
>   if the monitoring TNC's firmware treats an SSID of
>   "zero" as effectively no SSID at all for display
>   purposes.
>   The low-level WIDE1-1 home digis far outnumber the
>   WIDE2-n "true wides".   Beaconing WIDE1-1 as the
>   first hop from aircraft (that have a range of
>   hundreds of miles/km line-of-site) can potentially
>   trigger hundreds of home WIDE1-1 digis
>   simultaneously,  when then ALL retransmit to the
>   nearest true WIDEn-N systems.  If the first hop from
>   an airborne station is a WIDE2-n only (which the
>   home digis just ignore) a few "true wides" rather
>   than hundreds of home stations will be triggered.  
>   Yes, the whole scheme is a kludge to work around the
>   limitations of 20-year-old "clunker" TNC hardware,
>   but it does kinda' sorta' work.........
>   ----------------------------------------------------
>   --
>   Stephen H. Smith    wa8lmf (at) aol.com
>   EchoLink Node:      WA8LMF  or 14400    [Think
>   bottom of the 2M band]
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>   Home Page:          http://wa8lmf.net
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>     http://wa8lmf.net/DigiPaths
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