I just helped set up the Ramy Yanetz ASG29's TRIG TT21 transponder with a TN72 GPS Source to use as a TABS ADS-B out system. That along with PowerFLARM in his glider makes for a pretty capable overall traffic awareness/collision avoidance system.

Here is a screenshot of my portable Stratux ADS-B receiver (as would be used in many GA aircraft) receiving the ADS-B signal from the TT21 over 20 nautical miles away. Yes, it's a wave day out at Williams.

https://drive.google.com/file/d/1Kik...SlslyEyMPo62Mu

And again just an reminder, the TN72 is a ~$350 (+ GPS antenna + install costs) GPS Source that can easily be added to any Trig transponder to deliver ADS-B Out in your glider. (If you need full 2020 Compliant ADS-B Out it's a little more involved). This is low-enough cost that it will likely be a "just do it" choice for owners who already have a Trig transponder, and who especially want to provide more visibility to GA traffic (and it makes your glider visible to PowerFLARM buddies at much longer distances).