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[aprssig] Multiple SSID's from one station, with the New N Paradigm.

Bob Bruninga bruninga at usna.edu
Tue Dec 16 20:04:12 UTC 2008


Hams should look on this as an pooprtunity.  It should be trivial to find the source, if the APRS system in that area is using traceable New-N.  AND then operators learn about their network and do a little smart testing.

THis is the modern day equivalen of DFing.  ANd APRS is the perfect tool for it, but users just need to undersdant the ntwork and what they are looking for.

GOod luck.  But a traceable New-N network will do wonders for tracking down these mistakes.  Yes, this is a known problem in the D700 and why we have moved to TRACEABLE Widen-N.

good luck

Bob, WB4APR


---- Original message ----
>Date: Tue, 16 Dec 2008 12:18:11 -0000
>From: "Dave Baxter" <Dave at emv.co.uk>  
>Subject: Re: [aprssig] Multiple SSID's from one station, with the New N Paradigm.  
>To: "TAPR APRS Mailing List" <aprssig at tapr.org>
>
>Cheers Bob...
>
>Current suspects involve a rouge D700 somewhere.  It's also prevelant in
>France, and Ireland too it seems.  The decrementing of the originating
>SSID that is, both those areas use WIDEn-N, though it has been seen with
>TRACEn-N too, though not as bad.
>
>I know DigiNed, and am planning on using it sometime (or AGW Digi) so
>will take care with the settings, and get people to test it.
>
>Cheers.
>
>Dave G0WBX
>
> 
>
>> -----Original Message-----
>> From: Bob Donnell [mailto:kd7nm at pugetsound.net] 
>> Sent: 15 December 2008 20:33
>> To: 'TAPR APRS Mailing List'
>> Subject: Re: [aprssig] Multiple SSID's from one station,with 
>> the New N Paradigm.
>> 
>> If I had to venture a guess, someone on the network has tried 
>> to implement WIDEn-n with digined, or some other 
>> user-configurable softare handling the digipeating function.  
>> That station has a bad configuration, one that instead of 
>> decrementing the digipeating SSID, is instead, decrementing 
>> the sending station SSID.  There are not too many choices of 
>> widely disseminated software available, in that regard.  With 
>> all of the different things that have been tried on APRS in 
>> the Pacific Northwest, the problem you've documented is not a 
>> problem that I've ever seen reported having been done 
>> locally.  Don't feel like a Lone Ranger.  A number of 
>> modifications to the APRS digipeating paradigms have had 
>> their roots here.  Just like roots, some of those roots seem 
>> to run into solid obstacles, which slows their growth.
>> 
>> 73, Bob, KD7NM
>>  
>> 
>> -----Original Message-----
>> From: aprssig-bounces at tapr.org 
>> [mailto:aprssig-bounces at tapr.org] On Behalf Of Dave Baxter
>> Sent: Monday, December 15, 2008 12:52 AM
>> To: TAPR APRS Mailing List
>> Subject: Re: [aprssig] Multiple SSID's from one station,with 
>> the New N Paradigm.
>> 
>> Hi Keith....
>> 
>> Nope, the sending station only used one ssid -15.  There is something
>> elsewhere in the network (such as it is) that is causing this.   It is
>> one of the several reasons why England has not moved to Newn-N in the
>> past.   There is strong anecdotal evidence that misconfigured 
>> D700's are
>> a probable cause.
>> 
>> Believe me, trying to explain to several people who still 
>> think that the new WIDEn-N system is the same as WIDE (and 
>> not tracable) is a near vertical struggle.  They keep talking 
>> about this and not making clear which paradigm they are 
>> talking about, just to add to the confusion.
>> 
>> Regards.
>> 
>> Dave G0WBX
>> 
>> > -----Original Message-----
>> > From: Keith VE7GDH [mailto:ve7gdh at rac.ca]
>> > Sent: 13 December 2008 22:09
>> > To: TAPR APRS Mailing List
>> > Subject: Re: [aprssig] Multiple SSID's from one 
>> station,with the New N 
>> > Paradigm.
>> > 
>> > Dave G0WBX wrote...
>> > 
>> > > Following the recent IARU R1 meeting in Cavtat, and the resulting 
>> > > recommendation that Region 1 adopts the Newn-N paradigm...
>> > 
>> > I was pleased to hear that. There's a lot to be said for having 
>> > universal settings that will work everywhere without having to 
>> > reprogram as you travel.
>> > 
>> > > several people in the UK APRS network have been
>> > investigating how best
>> > > to adopt it.  Notwithstanding that many think it's not 
>> necessary to 
>> > > change from RELAY,TRACEn-N to WIDE1-1,WIDEn-N etc, for many
>> > reasons,
>> > > not least this following behaviour seen on air..
>> > 
>> > > 2008-12-08 14:36:12 UTC:
>> > > G7III-15>APRS,MB7UW*,WIDE5-3,qAR,G0CGL-12
>> > > :!5124.12N/00046.23W& Test Dup SSID: W5-5
>> > 
>> > > 2008-12-08 14:36:21 UTC:
>> > > G7III-14>APRS,MB7UW*,WIDE5-3,qAR,G0WKM-2
>> > >:!5124.12N/00046.23W& Test Dup SSID: W5-5
>> > 
>> > > 2008-12-08 14:36:25 UTC:
>> > > G7III-13>APRS,MB7UW*,WIDE5-2,qAR,G0WKM-2
>> > > :!5124.12N/00046.23W& Test Dup SSID: W5-5
>> > 
>> > > 2008-12-08 14:36:36 UTC:
>> > > G7III-12>APRS,MB7UW*,WIDE5-1,qAR,G0WKM-2
>> > > :!5124.12N/00046.23W& Test Dup SSID: W5-5
>> > 
>> > > Note the decrementing SSID of G7III, this is caused by a digi 
>> > > somewhere in the network, but is proving illusive to track
>> > down. G7III
>> > > of course only used one SSID, -15.
>> > >
>> > > It is (again I'm told) one of the main reasons why the UK (well, 
>> > > England at least) has stuck with RELAY,TRACEn-N as it 
>> doesnt happen 
>> > > with that path method.
>> > 
>> > In North America, we have made WIDEn-N traceable and the 
>> old TRACEn-N 
>> > isn't used... except for a few hold-outs. We could instead adopt 
>> > TRACEn-N and make that traceable againa, but that would involve a 
>> > change for many thousands of users. Not that it makes a lot of 
>> > difference, but WIDEn-N saves one byte compared to TRACEn-N, but of 
>> > course the length of the digipeated packet increases each 
>> time it is 
>> > digipeated.
>> > However, the advantage is in being able to see the actual 
>> path and no 
>> > dupes. Yes, you have tht now with the old TRACEn-N, but I 
>> think it is 
>> > a very worthwhile goal to have universal settings.
>> > 
>> > RELAY isn't traceable and can lead to dupes and 
>> ping-ponging between 
>> > digis.
>> > 
>> > In the example above, it appears the SSID was changed by the 
>> > originating station... G7III-15, G7III-14, G7III-13, G7III-12. The 
>> > beacon comment indicates "Test Dup SSID". Are you saying that G7III 
>> > only transmitted with one SSID? If so, something screwy is going on.
>> > 
>> > > Someone has said this...   "...there is a D700 somewhere 
>> > with UIFLOOD
>> > > set with NOID enabled." Is this the case, or is there
>> > something else
>> > > happening?
>> > 
>> > I'm not sure what is causing it.
>> > 
>> > > Was this odd behaviour seen in the USA when the New WIDEn-N
>> > system was
>> > > first rolled out?   If so, how did you track it down and fix it?
>> > 
>> > No. There was a transition period where most digis and 
>> mobile stations 
>> > changed over, but I've never heard of what was shown in the 
>> examples 
>> > you provided going on if the originating station wasn't 
>> changing the 
>> > SSID.
>> > Perhaps someone within earshot of G7III and some of the 
>> nearby digis 
>> > might be able to observe what is going on. The WIDEn-N should 
>> > decrement.
>> > The callsign-SSID of the originating station should most 
>> definitely be 
>> > changing.
>> > 
>> > 73 es cul - Keith VE7GDH
>> > --
>> > "I may be lost, but I know exactly where I am!"
>> > 
>> > 
>> > 
>> > 
>> 
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>> 
>> 
>> 
>> 
>
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