[aprssig] IGate FIlter for AMSATS?

Pete Loveall AE5PL Lists hamlists at ametx.com
Sun Feb 26 08:48:07 CST 2017

We ABSOLUTELY do NOT want delayed packets of ANY sort. That BREAKS APRS-IS and is the cause of many dupes, out-of-sequence packets, etc.  It assumes (bad word) that the SatGate will see the digipeated packet of the direct station either via the satellite or APRS-IS and that is an invalid assumption.

I assume terrestrial stations will use the same path which eliminates the ability to differentiate between terrestrial and satellite based solely on their packet structure.  Therefore, a choice must be made as to what is more important: someone within direct range of a SatGate needing to see their packet as digipeated on APRS-IS or seeing all satellite generated packets on APRS-IS.  I would say the priority is the latter as the station transmitting via the satellite should also be able to receive their digipeated packet directly from the satellite on RF and APRS-IS makes no difference in that case.

Since you make this point of satellites using a path which could be used by terrestrial stations, I will remove the "drop heard direct with path" capability from the SatGate mode in APRSIGate (javAPRSSrvr IGate module).  I believe it is far more important to see satellite-generated packets than to worry about the one or 2 hams who are nearby a SatGate that aren't satisfied with seeing their packets digipeated directly from the satellite instead of via APRS-IS.


Pete Loveall AE5PL
pete at ae5pl dot net

> -----Original Message-----
> From: Robert Bruninga [mailto:bruninga at usna.edu]
> Sent: Sunday, February 26, 2017 8:01 AM
> To: Pete Loveall AE5PL Lists <hamlists at ametx.com>
> Cc: TAPR APRS Mailing List <aprssig at tapr.org>; Robert Bruninga
> <bruninga at usna.edu>
> Subject: Re: [aprssig] IGate FIlter for AMSATS?
> Drats...  I forgot that the telemetry from the sats themselves are direct!
> Grrrr...
> So although this is a great idea, most of the APRS satellites all DO transmit with
> a one hop path.  They are transmitted via APRSAT so that any telemetry packet
> that might get heard by any other APRS satellite will be digipeated once.  THis
> way we can get a two-hop over the horizon data.  First time I saw it, the ISS was
> over North Africa, and heard by PCSAT over the atlantic (no one else in
> footprint) and the digipeated packet was heard in Maryland.
> So I guess maybe the held-until-not-seen-on-IS imight be the only solution that
> covers all cases withouth having to be managed call-by-call?
> Bob, WB4APR

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