[aprssig] Weird Behavior on the APRS-IS

[Steve Dimse]

On Feb 17, 2014, at 6:27 PM, Stephen H. Smith <WA8LMF2 at aol.com> wrote:
> 
> Normally, one assumes that whenever anything is fed into an APRS-IS server, it propagates to all the others within a second or two.   Here I was seeing a nearly 20-MINUTE delay.

Were you only using the ISS position as the indicator of a 20 minute delay? Perhaps someone is feeding a bad position based either on clock offset or old keplerian elements.

I've been chasing a problem with a 45 second delay but it seems to only involve the CWOP weather data. A 20 minute delay would not be impossible (say from a saturated digi that holds data for long periods), but it is much more likely that someone is just generating bad positions.

I never trust the ISS position on the APRS IS because I've seen lots of bad data over the years. findU runs its own orbital code to generate ISS position for www.ariss.net, it also generates a +5 minute and +10 minute position so you can see where it is heading, which I find a lot more useful than the current position anyway!

Steve K4HG