Phantom Pings

[Alex]

I've noticed over the past few weeks that when reviewing my APRS path (on APRS.fi) to a given location, that about an hour later, there will be a "phantom ping" with a timestamp and location close to my originating, initial ping of the day. There is no way I'm actually transmitting during this phantom ping time as my radio is in my truck powered off with switched off ignition voltage, for one.

I wonder if anyone else is experiencing this bug?

Thank you and 73,
Alex, AK4AM

[Heikki Hannikainen]

Probably a misbehaving iGate somewhere, a gateway is holding the packets
and sending them out with a delay. aprs.fi does try to detect and filter
delayed duplicate packets out, but it's difficult especially with packets
which do not have an embedded timestamp. It'd be great if the APRS
protocol had timestamps or serial numbers in all packets, but
unfortunately they don't.

There is a classic bug in some Kantronics TNCs used in old igates, where
the TNC buffers packets internally and sends them out to the computer over
the serial line with a delay. I suppose that's still the most common
reason for this issue, but who knows if some new equipment has the same
problem.

- Hessu