[aprssig] KPC3+ Question

Tue May 22 12:46:50 EDT 2007

You also asked:

> Is there a way of BULIST-ing or excluding certain 
> stations, to control what a digi will actually repeat?

Again, assuming you really want only one-way paths to a single
point and want to cutoff everyone else in the remote areas of
your system from seeing those close to that single point, then
there is something you can do.

No matter how all of your 8 digis are arranged, there are some
that are
Immediately adjacent to your one-single-point site where you
want to collect the data.  These 1st tier digis only need to
digipeat a WIDE3-3 packet ONCE.  Therefore you can put WIDE3-3
into the UIDIGI LIST settings.  Then when a WIDE3-3 station is
in that area, their packets are only digipeated ONCE.  But
everyone else beyond that first tier wont see them.  TO me this
undermines the intent of APRS...

Repeating myself, if the central single site you want to receive
all this data is more or less centrally located, I would think
that WIDE2-2 would get packets there from all 8 surrounding
digis.  If the one single site is at the end of a very long
string of 8 linear digis, then you are going to have to tell
your users to use SS1-1,SS7-7.  So it all depends...

Bob, WB4APR

> -----Original Message-----
> From: aprssig-bounces at lists.tapr.org 
> [mailto:aprssig-bounces at lists.tapr.org] On Behalf Of Robert
Bruninga
> Sent: Tuesday, May 22, 2007 12:25 PM
> To: jim at stuckinthemud.org; 'TAPR APRS Mailing List'
> Subject: RE: [aprssig] KPC3+ Question
> 
> > A question for all KPC3+ experts out there.
> 
> Jim, I'm going to answer based on the lowest common
denominator
> of interpretation of the information you have provided.  That
> is, I am assuming you have not implemented the New-N paradigm
> settings on these digis.  Forgive me if you already have...
My
> answers are more for others who may be following this thread.
> 
> > I have a scenario with eight KPC3+ digi's in 
> > a mountainous area, which are set up to get 
> > location beacons back to a central point.
> 
> Probably you mean they are "set up" situationally located for
RF
> such that they can all see the central point, that is one
thing.
> Again, I will assume a worst case assumption and assume you
may
> be talking about "TNC settings"...  In that case, there is
> practically nothing you can do in a digipeater to "force" any
> particular packets anywhere.  Where the packets go is up to
the
> originator of the packet.  If it takes 3 hops from one of
those
> digis to get the data back to the single specific point, then
> users in that area will have to use WIDE3-3.
> 
> > Digi's are hill-top, so I want to stop beacons from 
> > being repeated in areas they don't need to be (i.e. 
> > cut down the redundant RF traffic).
> 
> Simply implementing the New-N Paradigm in the KPC-3+'s should
> cut down on all dupes perfectly.  It eliminates all duplicate
> packets.  Each New-N digipeater repeats each packet once and
> only once.
> 
> > Control of the route via the sending station is not 
> > possible as they can be anywhere, which is why I'm 
> > looking for a "system" solution.  KPCs are running v9.1.
> 
> The system solution is to determine what the worst case path
is
> (say 3 hops) and have everyone in the area use three hops.
This
> is easy to convey to users, since all DIGIS under the New-N
> paradigm are supposed to show as the first few bytes of their
> Position Comment something like "W3,SSn-N" to tell users that
> WIDE3-3 is recommended in that area (and SSn-N is supported).
> This displays nicely from all New-N digis.
> 
> Maybe you only want packets to go to the central site, but
> focusing too much on that one-way path will exclude users in
> your "system" from seeing each other at the extremes.  In my
> opinion, you want packets originated anywhere in the area to
be
> able to hit all other digis, so that all users in your system
> see each other too.  APRS is for all-to-all communications.
> Most mobiles receive and display data as well as just transmit
> it.
> 
> On the other hand, 
> 
> If your "system" is well defined and truly has a specific well
> defined and well understood mission, then you can set it up
with
> a specific SSn-N system (SS can be from 2 to 5 bytes long).
> Then tell all users in the system to use SSn-N where N is the
> maximum worst case path from the fartherest extremes of the
> system.  This will guarantee that all 8 of your digis repeat
> each packet, but that NONE of the sourrounding states or areas
> will see any of them.  This might be unfair for the overall
> regional APRS communicatinos, but it will accomplish what you
> say you want.  You can even use SS7-7 without regret, because
no
> matter how big "7" is, these packets will still only hit each
of
> your eight SSn-N digis once and only once.  And not spread
> outward beyond your "system".
> 
> The KCPC3+'s all support both WIDEn-N and SSn-N
simultaneously,
> so this way you can meet your specific unique objective for
> specific users while also serving the general APRS mobile
public
> as well.
> 
> Hope this helps.
> 
> By the way, if you do implemente the SSn-N system, then the
> paths are the most traceable if the users use the path of
> SS1-1,SSn-N.  This will identify the packets when they arrive
> anywhere by the FIRST and LAST digis in the path.
> 
> Bob, WB4APR
> 
> 
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