[Xastir] corrupt packets

[Lynn W. Deffenbaugh (Mr)]

If you mean corrupt packets are causing object definition overwrites, 
well, that's the definition of objects.  If you hear someone else 
beaconing "your" object, the spec says you are supposed to "cease 
transmitting" your object.  However, UI-View (and apparently xastir) 
implemented this as "adopt the received definition" and duly modify 
their local definition of the received object.

Lynn (D) - KJ4ERJ - Author of APRSISCE for Windows Mobile and Win32

PS.  The full spec section on "Replacing an Object / Item" in 
aprs101.pdf states:

> A fundamental precept of APRS is that any station may take over the
> reporting responsibility for an APRS Object or Item, by simply 
> transmitting a
> new report with the same Object/Item name.
> The replacement report may specify the existing location or a new 
> location.
> The original station will cease transmitting an Object/Item Report when it
> sees an incoming report with the same name from another station.

APRSISCE/32 doesn't have this implemented yet, but my plan is two-fold 
to avoid this issue.  1) When an locally-declared object is heard from 
another station, the Xmit Enabled of that object will be turned off and 
an internal message generated to inform the local operator.  2) Support 
a "Keep It Mine" configuration option that ignores the fact that someone 
tried to adopt (commandeer) the object and simply retransmit the local 
definition on the next interval (this is basically what it does now 
being oblivious to the received object).

However, in either case, the received object WILL be placed on the map 
and the information duly recorded and displayed until something 
different is received (as in #2 above) for the object in the future.

Oh, and if anyone transmits an object or item that commandeers a real 
station, of course the station isn't aware of this and on the next 
normal beacon "ownership" of that ID reverts back to the "real" station.


On 10/19/2011 11:02 AM, Mike Swiatkowski, AA9VI wrote:
> The last couple of days I have been reading about corrupt packets getting transmitted over the air.  This sounds similar to what I had mentioned a month ago.  There was no obvious solution then.  I use a KPC3 and Xastir 2.0.0.  I could find no solution until I set permissions on the objects.log and objects-temp.log file to 555.  So, there is some over the air feedback mechanism causing bad packets to be heard over the air and then get fed back into Xastir and then overwrite the default settings. Wouldn't a simple solution be to not have that feedback algorithm? 
>
> Mike, AA9VI
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