gps --> OpenTracker+ --> Radio --> 1/4 wave "ground plane" antenna
The GPS appears to have worked fairly well, as did the OpenTracker+. There were issues with the radio.
Concerns with the radio turned our attention to two issues - Data logging and antenna design. Data logging is being taken up as a separate project.
Perhaps the biggest issue with the antenna design from the start is that it had an inadequate ground plane. I suspect that this is why sometimes it worked in tests (when I set it on the aluminum window frame) but often it did not.
Instead of constructing a 19" diameter ground plane (lots of pointy bits), thinking about turning attention to a dipole construction. I found nice instructions for a dipole bicycle antenna which looks very suitable. I love how they used a fiberglass bicycle flag as the structural element.
I'm a little bit curious as to how the best way to mount this would be. If we have it centered, running through the payload it would be less likely to be destroyed. If we have it off-center, it would be far easier to mount and possibly less likely to have issues with the other electronics running in the payload area.