[aprssig] Need Path Mentoring

J T w0jrt at yahoo.com
Thu Sep 20 17:43:09 EDT 2007


Steve Noskowicz <noskosteve at yahoo.com> wrote: K9DCI-9>TRRW0S,WIDE1-1,WIDE2-1,qAR,N9OIG:'t(Fl!h>/]"6]}

Meaning that:  IGate N9IOG heard me directly and shot
me into the APRS-IS, right?  _____
Correct.
2- Seeing WIDE3-3 in the first slot suggests a Digi is
substituting “WIDE3-3” for my “WIDE1-1” since there
are digi calls after it?  Eh?
That's sure what it looks like.  It appears that there is a mis-configured digi or fill-in digi that is doing call-sign substitution but sticking WIDE3-3 in there instead of its own callsign.  There is evidence to support this in the packets shown below, where other digis have seen that the packet was retransmitted by station "WIDE3-3" (with that digi marked as being used in the AX.25 packet) and proceeded to digi you packet using the remainder of the path.  This mystery station can apparently be heard directly by K9ESV-3, K9ABC-10, EX9MKX, WA9CJN-15, and K8BRC.  
Excerpts from Raw data:
K9DCI-9>TRRW0S,WIDE3-3*,K8BRC*,WIDE2*,qAo,N8FQ:'t(El-Q>/]
K9DCI-9>TRRW0T,WIDE3-3*,K8BRC*,WIDE2*,qAo,N8FQ:'t(EliW>/]"6[}

K9DCI-9>TRRW0S,WIDE3-3,K9ESV-3,WIDE2*,qAo,W9TMW:'t(El-Q>/]

Note that in these examples, there are actual call
signs with the “*” appended.  Is that part of “The
New”??  or a mix of new and old.   I thought the “old”
was to accept it and append the “*”,   but new is only
to substitute – but remember that half-life effect.
Neither, really.  In the new-N paradigm WIDEn-N is fully traceable, so each digi that passes on the packet will perform callsign substitution.  The asterisk isn't related to the old vs. new paradigm but is a function of the receiving TNC.  An asterisk appears next to the digi that the receiving station heard the packet from (or the entire string of digis, up to the last one heard, depending on how the TNC presents this data to the user).  But to know what the original path was, when the "N" in WIDEn-N gets decremented to zero the digi that does that not only inserts its callsign in the string along with setting the bit that indicates that digi slot was used, but it keeps the WIDEn-0 in the list (where 0 is typically not displayed) and also sets the bit to indicate that slot was used.
Seeing this:
 K9DCI-9>TRRV2Q,K9ESV-3,WIDE1*,WIDE2-1,qAR,N9OIG:'t+O
Hu>/]"6X}
Does this say that K9ESV-3 is accepting the WIDE1-1?  
Also, rather than substituting, is it *inserting* its
call and putting the “*” after the “WIDE1” part of the
“WIDE1-1”  ???
Yes, K9ESV-3 is digi'ing on WIDE1-1, performing callsign substitution, but to keep the history of the original path, it keeps the WIDE1-0 in the list and also flags it as being used such that the rest of the path will be used appropriately by other digis, since digis have to be used in order from left to right.
The fella doing K9ESV, while a nice guy trying to do
it correctly, has expressed doubt and asked me (yea,
right) to look at his parameters.
It looks like it's configured pretty well.  It appears to be a combination WX station and full digi.  It appears to be using a single 2-hop path (WIDE2-2) instead of a varying path (from 0 to 2 hops) as is often used in stand-alone digis, but since this is sending WX data with each transmission path may be appropriate for that area.

-Jerome, W0JRT

       
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