EC-121 & ALRI

Contributed by Tom Page

EC-121 Superconstellation radar aircraft were operated by US Air Force personnel off the East Coast and the West Coast (and by US Navy personnel further out). This system was known as "Airborne Long-Range Inputs," or ALRI.

The East Coast Air Force EC-121 aircraft were configured for SAGE operations. That is, the radar data were digitized, transmitted by microwave carrier to an AN/GSC-7 receiver at one of four ground-based long-range radar sites along the coast, and then sent to a regional SAGE direction center via land lines.

The four ALRI sites on the East Coast were North Truro AFS, MA (Z-10); Montauk AFS, LI, NY (Z-45); Cape Charles AFS, VA (Z-56); and Fort Fisher AFS, NC (Z-115).

Conversely, the West Coast Air Force EC-121 aircraft were *not* configured for SAGE operations; their radar operations were entirely "manual." Those aircraft carried additional radar operators and scopes, plus plotting boards. Aircraft tracks were reported to a regional SAGE direction center by voice radios (via GATR sites). ALRI was phased out circa 1974.