… "It's easy" followed by "use any AX.25 1200 baud packet system” makes
sense to you experienced hams, but that covers a lot of new ground for me.
Although “rocket science,” it CAN be done with your HT … (grin)
Here is a reference page of good material. Look at Joanne’s excellent article on working the ISS via packet.
https://amsat-uk.org/beginners/how-to-work-the-iss-on-aprs-packet-radio/ https://amsat-uk.org/beginners/how-to-work-the-iss-on-aprs-packet-radio/
And know now that the ISS’ packet work is on 440 - NOT 2M - due to an equipment failure on board. Here is a suggested frequency chart for you to accommodate now for Doppler on that 440 frequency …
http://www.work-sat.com/Home_files/WS-50-85-ISS.pdf http://www.work-sat.com/Home_files/WS-50-85-ISS.pdf
Clint Bradford K6LCS (909) 999-SATS