Ledsled----so this J curve you speak about.....Is that the East Coast ( CNS to ADL ) Radar coverage area above 10,000' is it?
Ok sorry didn't get the meaning of J curve until now.
Either way it leaves a huge hole over the GAFFA he can't fly in above FL280, an area that benefits from ADSB and I can see why ASA wants it fitted to all Aircraft so they can use the airspace much more efficiently. ( and make more money, what they call a win win )