[aprssig] KPC3+ Question

Tue May 22 15:18:45 EDT 2007

> Currently using WIDE3-3 anyway as a beacon will get 
> to the monitoring point in 3 or less...
> Looks like we can't do what I was looking to with the 
> existing equipment, so we'll just carry on as we are!

You can do the one thing, and that is to make the first tier of
digis outward from the Monitoring site have WIDE3-3 in their
UIDIGI list.  This will at least cut the QRM from all users in
range of those digis to one hop only.  Depending on how many
digis can be heard direct at the monitroing point, this could be
significant if say it was 3 of the 8.

Bob

> -----Original Message-----
> From: Robert Bruninga [mailto:bruninga at usna.edu] 
> Sent: 22 May 2007 17:47
> To: bruninga at usna.edu; 'TAPR APRS Mailing List';
jim at stuckinthemud.org
> Subject: RE: [aprssig] KPC3+ Question
> 
> 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
> > 
> > 
> > _______________________________________________
> > aprssig mailing list
> > aprssig at lists.tapr.org
> > https://lists.tapr.org/cgi-bin/mailman/listinfo/aprssig
> > 
> 
> 
> 