So ive been messing with APRS for a few months now and mostly its been working fine, running a Mobilinkd TNC3 into my Baofeng UV-5R which i know isnt ideal but it gets the job done. The problem started maybe two weeks ago where my position on aprs.fi is showing me like 40 miles northwest of where i actually am. The packets are definitely getting out because i can see them being digipeated and hitting the igate, but the coordinates in the packet are just wrong.

I checked the GPS lock on my phone (im using APRSDroid on Android) and it shows my correct position fine in other apps. Thought maybe it was a datum issue or something but honestly i dont know enough about that to even troubleshoot it properly. Tried power cycling everything, re-pairing the Mobilinkd, nothing changed. Anyone run into this before? Is there some setting in APRSDroid that controls how the GPS data gets formatted into the packet?

yeah APRSDroid has had some weirdness with certain Android versions and how it reads the GPS provider. go into settings and check which location source its set to use — if its on "network" instead of GPS that could do it, network location can be pretty far off especially if youre not near a lot of cell towers. also check if you have any mock location apps running in developer options, those can mess with what APRSDroid sees even if your maps app is pulling real GPS fine.

the other thing worth looking at is the NMEA sentence format. if the TNC is somehow getting the position from a different source or theres a parsing issue the coordinates can come out scrambled. id try disconnecting and reconnecting the Mobilinkd a few times with APRSDroid fully closed and restarted between attempts, sounds dumb but sometimes it picks up a stale position from the first lock.

40 miles northwest is a weirdly specific offset, makes me wonder if its a sign error somewhere in how the lat/lon is being encoded. like if one of the decimal degrees is getting the hemisphere wrong or truncated. i had something similar once when i was using Direwolf and had a config typo in my position — came out like 3 degrees off because i had the wrong number of decimal places. probably not exactly your situation but worth looking at the raw packet data on aprs.fi, click on the packet and look at the actual string, sometimes the error is pretty obvious when you see it written out.