"The kluge I was doing for my rocketry might be still a solution here for APM.   On the drone end, one could use an arduino mini with a program to append a call-sign with every sentence or packet and on the receiving end, another arduino mini to…"

"Regarding call-sign being transmitted at the end of communication:  I'm not certain that is absolutely necessary with packet radio.  Take APRS for example, the call-sign is transmitted at the beginning of every packet, The systems I've seen do not…"

"The call-sign that the minim-osd provides should satisfy FCC requirements if you were transmitting video and data on a regulated ATV frequency.  
It probably won't cover us if we were transmitting data using a data modem is on a different frequency…"

"Following the MAVLink path, looks like some work has already been done in this area with the Minim-OSD module. This is primarily for use with a video feed.  This is an add-on extras to the basic fw. Don't know much other than what I've read so far.…"

"Sorry if this is a repeat, it seems I did not post my previous reply properly. For tracking my rockets, I use an Arduino between the GPS module and the data transceiver with a small program that appends my call sign as a header to the NMEA sentences…"

"Sorry, I realize this is a stale thread, but has there been any progress on this? The only other thread I've found with reference to this subject matter was consumed in a fight over appropriate use of GPLicensing. "