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[aprssig] APRS Objects

Robert Bruninga bruninga at usna.edu
Tue Aug 28 16:58:56 UTC 2007


> My originating station isn't very high or powerful, PHG3000.
> I'm configured to transmit WIDE2-2, and ... I can [not]
> adjust it to anything smaller for an object like that

Which is one of the reasons why permanent objects from client
stations are not a good idea.  The rest of the reasons are
posted on this web page for local-voice repeater frquency
objects(about 80% down):

http://web.ew.usna.edu/~bruninga/localinfo.html

Some of these reasons for not generating objects from APRS home
stations  using client APRS software are:
* objects are not on a reliable 10 minute rate for local info
* or are too infrequent to be of any value 
* often transmitted multiple hops instead of DIRECT ONLY
* therefore, add QRM everywhere 
* have a high probability of collision with other users 
* take twice the channel time for a digipeat 
* There is no limit to the ego or number of such objects 
  a local client can generate 

The best place to put an object is in the BTEXT of a digipeater
so that it is only transmitted when the digi hears a clear
channel.  This eliminates the load or potential for collision
with other stations.  But since the BTEXT of each digipeater is
supposed to alerayd have in it, the object for the local voice
receommended frequency, then it is arealdy in use.

We always want these local objects local.  No spam out of area.

Hope that helps
Bob, WB4APR
> 
> On 8/28/07, Robert Bruninga <bruninga at usna.edu> wrote:
> > > Subject: [aprssig] APRS Objects
> > > Am I doing this right?
> > > http://www.findu.com/cgi-bin/find.cgi?call=FMH
> > >
> > > NE3R>APX190,WIDE2-2:;FMH
> > *280032z3925.41N/07724.93WhFrederick
> > > Memorial Hospital
> >
> > Depends on what you mean by right?
> >
> > Here is my take on it.
> >
> > 1) Yes it is the correct format for an object.
> > 2) From Frederick Maryland that object will be seen in 4
states,
> > MD, VA, WV, PA at least depending on how high your
originating
> > station is.
> > 3) Since everyone in those states knows there is probably a
> > hospital in Frederick Maryland, I don't think they are
> > interested in seeing this from so far away.
> >
> > 4) The only people who need to see this object are those in
the
> > local area.
> >
> > Therefore, I would cut back the path length to either a
direct
> > packet, or at most one  hop.  Otherwise the object might be
> > considerd as spam by the other 200 people who will receive
it,
> > day-in,day-out forever
> >
> > I think it is a good idea to keep local info local.
> >
> > But wihtout knowing your intent, of course, you could be
trying
> > to do something entirely differerent...
> >
> > Just my opinion.
> > Bob
> > WB4APR
> >
> >
> > _______________________________________________
> > aprssig mailing list
> > aprssig at lists.tapr.org
> > https://lists.tapr.org/cgi-bin/mailman/listinfo/aprssig
> >
> 





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