[aprssig] How to Send to the APRS IS

Andrew Rich vk4tec at internode.on.net
Wed May 10 06:41:20 EDT 2017

Thanks Pete

You have confirmed my suspicions

It is time based checking

Is this information central for an individual to peruse ?


Sent from my iPhone

> On 10 May 2017, at 8:13 pm, Pete Loveall AE5PL Lists <hamlists at ametx.com> wrote:
> The dupe algorithm in the servers (and, I suspect, aprs.fi) is based on a 30 second -sliding- window and is individual packet-specific.  This means that, for instance, what appears to be inconsistent in your example is actually very consistent.  Packet #3 is a duplicate of packet #1 (29 seconds apart). Packet #2 does -not- replace packet #1 in the dupe check algorithm.  Packets are checked based solely on the sender callsign-SSID, the destination callsign (SSID ignored), and data without regard to later packets with different data (each packet is consider individually because that is how you prevent loops).  This is as designed and described at www.aprs-is.net
> 73,
> Pete Loveall AE5PL
> pete at ae5pl dot net
>> -----Original Message-----
>> From: aprssig [mailto:aprssig-bounces at tapr.org] On Behalf Of Andrew Rich
>> Sent: Wednesday, May 10, 2017 3:59 AM
>> To: aprssig at tapr.org
>> Subject: Re: [aprssig] How to Send to the APRS IS
>> And this lot I have no idea - they are all different positions
>> Unless it is time based
>> 2017-05-10 18:53:58 AEST: VK4TEC-
>> 9>APZ001,TCPIP*,qAS,VK4TEC:!2720.21S/15302.65E> [Duplicate position
>> packet]
>> 2017-05-10 18:54:08 AEST: VK4TEC-
>> 9>APZ001,TCPIP*,qAS,VK4TEC:!2720.20S/15302.65E> [Duplicate position
>> packet]
>> 2017-05-10 18:54:27 AEST: VK4TEC-
>> 9>APZ001,TCPIP*,qAS,VK4TEC:!2720.21S/15302.64E> [Duplicate position
>> packet]
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