Two ADS-B-compliant aircraft can be invisible to each other due to America's dual-frequency mandate - understanding why matters most in mountain terrain.
Radio Hangar explores The Two ADS-B Links, Ten Ninety ES and Nine Seventy-Eight UAT, and Why the FAA Has to Rebroadcast Traffic So the Two Halves of the Sky Can See Each Other.
Radio Hangar explores The Two Frequencies of ADS-B, Ten Ninety ES and Nine Seventy-Eight UAT, and Why America Split Its Traffic Picture Onto Two Radios That Can't Hear Each Other.