so ive been messing with APRS for a few months now, got my TM-D710G set up with an external GPS puck on the dash and its been beaconing fine, i can see my position on aprs.fi updating every couple minutes when im mobile which is great. but the messaging side of things is completely broken as far as i can tell.

tried sending a message to another local ham who also runs APRS and he says he never gets anything from me, and when he tries to send back i get nothing either. my SSID is -9 which should be fine for a vehicle. im running through a local igate that i can see is active and digipeating. path is set to WIDE1-1,WIDE2-1 which i thought was pretty standard.

is there something specific i have to enable on the radio for messaging or is this an igate thing where some of them are receive-only and wont pass messages back RF side? i feel like im missing something obvious here and its been bugging me for a while now.

yeah that's almost certainly the igate issue you mentioned. a lot of igates out there are one-way, they hear you and push your packets to the internet but they don't do the reverse path back to RF. for messaging to work you need a two-way igate (sometimes called a bidirectional igate) that will actually take a message from APRS-IS and transmit it back out on 144.390 so your radio can hear it.

you can actually check on aprs.fi by looking at the igate's info page, should say whether it's rx-only or bidirectional. if all the igates near you are rx-only thats your problem and basically nothing you change on the radio will fix it. the 710G itself handles messaging fine, its a solid rig for APRS, so i wouldnt go poking around the radio settings too much before you verify the igate situation first.

had this exact same headache last year. turned out there was a two-way igate about 15 miles away but my path wasn't hitting it because of terrain, i was only reaching the closer rx-only one. i ended up bumping to WIDE1-1,WIDE2-2 temporarily just to test and suddenly messages started flowing. not saying thats your fix cause more hops isnt always better but it helped me figure out which igate was actually handling my traffic. also double check the message format on the 710, theres a known thing where if the other stations callsign isnt entered exactly right including the SSID it just silently drops it.