so ive been running APRS for about 6 months now, mostly just tracking with a TM-D710G and a Mobilinkd TNC hooked to an HT as a backup. everything seems fine, my beacon hits the map fine, i can see myself moving around on aprs.fi when im driving, digi path is WIDE1-1,WIDE2-1 which i thought was pretty standard for my area.

the problem is messaging. im trying to send messages to another guy in my club, he's running an FT3D with APRS enabled, and neither of us can get messages through to each other. we can both see each other on the map no problem. ive tried from the radio directly and also through APRS-IS using aprsdroid on my phone. sometimes a message will go through after like 10 minutes and sometimes never. we were literally parked next to each other last tuesday and it still wouldnt work reliably which is what really confused me.

is there something specific about how the FT3D handles messaging that might be the issue? or is this just how APRS messaging is and im expecting too much from it

APRS messaging is honestly pretty flaky in general, you're not doing anything wrong necessarily. the way it works is the message has to get acked back to you and if any hop in that chain drops a packet the sender just keeps retrying until it times out. being parked next to each other is almost worse in some situations because you can end up hearing each other direct but the ack might not make it back through the path you're expecting.

one thing to check is whether the FT3D guy has his station set to respond to messages at all — some of those Yaesu portables have APRS messaging kind of buried in the menu and it might not be enabled or might be in a weird mode. also worth checking what path he's using, if hes running WIDE2-2 and you're close to a busy digi you might be getting a lot of collisions. aprsdroid through APRS-IS should honestly work better than RF in that case since its going internet to internet, so if thats also failing i'd look at whether his callsign-SSID is configured exactly right on both ends

yeah what the other guy said about the SSID is real important. if his radio is beaconing as W1XYZ-9 but you're sending messages to W1XYZ you're gonna get nothing. APRS treats those as completely different stations. i made that mistake for like two weeks when i first started messing with this stuff and felt pretty dumb when i figured it out lol