Ham ID Solutions
I believe I have solved the problem of identifying with my Ham Call Sign. The requirement is to ID every 10 minutes and at the end of the transmission.
For the Vortex 150 I found a Camera ID option under the Special menu. Normally it outputs a unique camera serial number but is turned off. I turned it on and then reset the last 6 characters with my call sign, KM6MSP. You can see this continually displayed at the bottom of the screen.
My FT Gremlin does not have any sort of Heads Up Display or camera ID that I know of, so in order to solve that problem I made a takeoff mat from a plastic cutting mat. These are readily available at any grocery store as a flexible cutting board. I would normally use it as a takeoff pad to keep the props out of the grass. With the addition of a simple printout which is laminated with clear packing tape it becomes an ID placard. All I have to do is point the camera at it at the end of the flight and I have met the ID requirement. Gremlin flights only last 3 to 5 minutes max so once at the end of the flight is plenty, and possibly at the beginning if I remember.
The Gremlin is only outputting 25mW with a range of about 100 ft. so it is highly unlikely that anyone but me would ever see the ID transmission, but the same technique could easily be used with more powerful video transmitters. Even at 650mW the range is so short that it is not much of a practical problem but if you ever want a theoretical solution, one does exist.
Beyond that, it can be argued that labeling the video TX is adequate. Accordingly I have labeled both the Gremlin and the Vortex 150 with my call sign and contact information. This is more difficult with the Gremlin due to its small size but you can see the minimum of information in the photo.
This idea of labeling the TX is really meant to apply to the TX that provides control signals, not video signals. It could be argued that the video signals are part of the control loop. I think it is an invalid argument, but with such low power and short range the requirement is more theoretical than practical anyway. Having contact information on the aircraft could possibly help you get your equipment back if you ever lost it though. It might also show a certain intent to follow the rules, especially if the person asking doesn't really know the rules.