so ive been trying to get my APRS setup working for about two weeks now and im just about ready to throw the whole thing out the window. running a Kenwood TM-D710G which has the built-in TNC and supposedly handles all of this natively, beacon is set to every 5 minutes on 144.390, and i can hear packets coming through on the speaker so i know the radio is receiving something. but my own position just does not show up on aprs.fi no matter what i do.

ive gone through the menu like four times and set the callsign with the SSID (-9 for mobile), the symbol is set to car icon, smart beaconing is on. the TX light flickers sometimes which i think means its transmitting? but nothing shows up. tried with a fixed beacon interval too just to rule out smart beaconing being weird. my antenna is just a mag mount on the car so maybe 3dB gain or so, should be totally fine for local digis.

is there a way to tell if the radio is actually keying up and sending a proper AX.25 packet or is it just... doing something that looks like transmitting but isnt. not sure how to even diagnose this without a second radio to monitor myself. anyone run into this with the D710

had almost the exact same thing happen to me with a D700 a while back, different radio but same TNC architecture basically. what fixed it for me was going into the APRS setup and making sure the data band was actually set to band A and that band A was the one tuned to 144.390. the radio can receive APRS on one band while trying to transmit on a completely different frequency and you'd never know unless you checked. sounds dumb but it got me for like three days.

also worth checking — is your GPS locked? if you have the GPS unit connected and it hasnt got a fix yet the radio sometimes just wont send a position packet at all, it'll sit there looking like its doing stuff but the position data is null so it holds off. if youre parked in a garage or something that'll do it. try it outside in open sky for 5-10 mins and see if the GPS icon on the display shows a solid lock before you start troubleshooting the RF side.

check if theres a digi anywhere near you that's actually up. aprs.fi not showing you doesnt necessarily mean you arent transmitting, it means your packets arent making it to an igate. if the local digi is down or your signal isnt hitting one, youre just shouting into the void and nobody hears it. you can look up your area on aprs.fi map and see if there are active digis nearby, and also check when they last heard something — if a digi hasnt gated anything in hours its probably offline.

the other thing i'd do is just grab a sdr dongle and use it on a second device to actually listen to your own transmission. tune to 144.390 and when you key up you should see a big spike and hear the packet burst. at least then you know the radio is actually putting RF out with data on it.