On Friday, May 29, 2015 at 7:45:05 AM UTC-7, John Galloway wrote:

The differences in the information transmitted by Flarm and ADS-B are
not minor. There is plenty of information included, or linked to, earlier
in this thread to explain what Flarm transmits and why.

John Galloway

Yep.

Has anyone actually pulled apart some of the (pre-encryption) Flarm transmissions? You would think that would settle this debate. I have not personally verified it, but have been told directly by FLARM engineers and the logic of not having to do flight path projections for every glider you are tracking individually makes sense to me when it is a relatively straightforward proposition to send out a handful of projected flight path points as part of each glider's transmission. That plus the dropped packet issue convinced me that this wasn't something the FLARM marketing people came up with just to snow people (BTW, I don't believe Flarm has any dedicated marketing people - which may explain some things).

It amazes me how much misunderstanding and misinformation is floating around out there on this. Glider pilots are generally pretty smart - though many are also dogmatic.

Andy
9B