To update the figure that Rod obtained last year, I understand that the number of Flarm units sold in the UK is now equivalent to approximately 25% of the UK gliders, and the figure is still growing.
Nobody knows for certain, but I suspect that there will be a higher proportion of cross-country gliders equipped with Flarm, than the average which includes all those that remain usually fairly local to their home airfield.
A small number of Flarm units have also been sold to power aircraft operators, I understand.
Re lack of direction information from transponders in aircraft detected by PowerFlarm: is it because there is only a single aerial on this portable kit, and consequently it cannot determine direction? ADSB and Flarm signals include the transmitting aircraft’s GPS coordinates, from which a comparison can be made with the receiving GPS position. I don't see how a transponder signal can give other than range (computed from signal strength) and height difference (computed from mode C transmission). If there is another way, could someone please educate me by saying what it is?
Chris N