Location changes too fast (adaptive limit)

[Korhan Buken - TA5FW]

2021-09-16 18:07:57 +03: TA5AQD-9>SV5Y83,YM5KAD,WIDE1,YM5KMR,WIDE2*,qAR,YM5KMS:`?0zl!<>/`"4(}RESUL DAN Herkese iyi gunler 73.._% [Location changes too fast (adaptive limit)]
2021-09-16 18:08:05 +03: TA5AQD-9>3V5X80,WIDE1-1,WIDE2-1,qAS,TA5DDS-10:`?0*n@f>/`"4&}_% [Location changes too fast (adaptive limit)]

Hello there,

A friend of mine uses Yaesu FTM-400 in his car. While my friend is actually at a different point, he always goes to the same point as if his FTM-400 radio does not actually send a beacon, or he goes to another point and returns to the coordinates he received from the GPS after a short while. And the "Location changes too fast (adaptive limit)" error appears above.

If anyone has any comments or explanations on this topic, we would love to hear it. I wish you good work.

TA5FW at 73

[Heikki Hannikainen]

You're possibly seeing delayed packets - some component on the network
over there (digipeater, igate?) is holding old packets for a longer while,
and then forwarding them, delayed.

This will cause stations to jump back to one of their older positions,
unless the algorithm on aprs.fi manages to catch them. The "Location
changes too fast" filter catches a lot of these - it figures out that it
would be impossible or very unusual for a station to suddenly move that
fast to an older position far away.

Sometimes it also causes "Rate limited (< 5 sec)" warnings as the delayed
packet may come in very close to a new, fresh packet.

To find the place where the packets are delayed, please look at the raw
packets: https://aprs.fi/?c=raw&call=TA5AQD-9&limit=300&view=normal

Select a longer range of packets (300, 500, 1000), and then go looking for
the errored packets. Press CTRL-F to bring up the search feature of the
web browser (to find text strings within the page), and copy-paste the
encoded packet data of the errored packet (the `?0zl!<>/`"4(}R or such in
this case, these are mic-e encoded packets) to the search field, and the
browser will nicely highlight all the copies of the same packets that have
arrived. You may then be able to figure out which igate or digipeater the
delayed packets have traversed.

Note that the "rate limit" error may happen just as well on a new, fresh
packet, or the delayed packet, depending on which one happened to arrive
first within a 5-second window.

- Hessu