[aprssig] ISS internet feed

Pete Loveall AE5PL Lists hamlists at ametx.com
Sun Mar 20 07:21:56 EDT 2011

That is not how it works and for good reason.  All APRS-IS servers implement the dupe filtering so in answer to your question, "No" you cannot have an "APRS-IS feeder" that ignores dupes.  The dupe sliding window at each server is 30 seconds.  This was purposefully selected to prevent large area delayed digipeated packets and slow servers from reintroducing "stale" packets.  There was a lot of testing and tweaking that went into that back in the 2000-2003 timeframe and it still holds today.

Dupe elimination is necessary to reduce loops and to reduce bandwidth requirements at the servers and at the clients.  APRS-IS is not an RF propagation tool because of this dupe checking nor can it be reasonably used for RF diagnosis other than at the source of specific packets.  The primary purpose of APRS-IS is to interconnect amateur radio RF APRS networks and to accomplish this, dupe checking, q-constructs, etc. are necessary to ensure the highest level of reliability under the architecture and protocol put in place over a decade ago.

Hope this helps.


Pete Loveall AE5PL
pete at ae5pl dot net

> -----Original Message-----
> From: Andrew Rich
> Sent: Sunday, March 20, 2011 2:32 AM
> Is it possible to set up and APRS -IS feeder that does not ignore dupes ?
> It would be nice to have a space APRS-IS feed for ISS that allows the
> subscribed stations to hear what other stations contributed , apart from the
> "winning" packet
> What is the latency rejection of an APRS-IS station ?
> How "late" can a packet arrive before it is considered not a dupe and classed
> as a "new" packet ?

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