On Wednesday, May 2, 2018 at 9:23:29 PM UTC-4, Tom BravoMike wrote:
If it's all about software, why can't we have software using the ADS-B transmission (more universal, stronger ergo better visible) to provide us, glider pilots, with the information (visual/acoustic) equal to that produced by FLARM.

I'm pretty sure that it is not 'all about software'. The two other 'biggies' are radio frequency bandwidth (limited) and the rate at which 3-D positions need to be broadcast. Position transmission rate must be limited to avoid saturation of the available bandwidth. To calculate collision avoidance between gliders (that are sharing a thermal), 3-D position broadcasts need to be very frequent, much more frequent than the rate needed for collision avoidance between powered aircraft with nominal separation.

I doubt that ADS-B out transmits frequent enough position reports to compute collision avoidance between gliders. Gliders frequently fly close to other gliders.

So you might ask, 'how come Powerflarm has enough bandwidth to do collision avoidance between proximate aircraft and ADS-B does not?' Part of the answer (I guess) is that Powerflarm uses lower transmission power (so the signal does not travel as far), and there are far fewer Powerflarm transmitters in range of other Powerflarm transmitters, than the number of ADS-B transmitters talking to each other in a Bravo airspace. Another guess is that a Powerflarm transmission is smaller than an ADS-B transmission.

ADS-B transmission is not encrypted, so if anyone would like to try to build Flarm like collision avoidance on top of ADS-B, there is nothing stopping you. I'd love to see that happen, but I'd not under-estimate the obstacles, and I would certainly not delay installing Powerflarm while waiting for something new to come on line.