College Eye

Lockheed EC-121 Warning Star and related Technology in the Vietnam War, 1967-1972

Sergio Santana

A rare insight into the development, operational deployment, and combat operations of a programme that eventually evolved into the ‘Mother of modern-day AWACS aircraft'.
Publication date:
July 2021
Publisher :
Helion and Company
Series :
Illustration :
100 photos, 15 artworks, 5-6 maps, 4-5 diags
Format Available     Quantity Price
ISBN : 9781912866328

Dimensions : 297 X 210 mm
Not Yet Published. Available for PreOrder.


During the Cuban Missile Crisis of 1962, the National Security Agency (NSA) of the USA realized that it was capable of reading transmissions emitted by SRO-2 identification friend or foe (IFF) transponders carried by Soviet-made combat aircraft airborne over Cuba.

After several years of development work, the resulting technology was installed in the form of the QRC-248 enemy IFF-interrogator system into Lockheed EC-121 Warning Star airborne early warning (AEW) aircraft deployed in support of US operations over North Vietnam, in 1967, within the Project code-named College Eye.

While deployed with extreme caution in order to safeguard ‘intelligence sources' - and thus remaining dependent on the North Vietnamese pilots activating their IFF transponders - the QRC-248 proved a true ‘eye-opener' for the Americans involved: all of a sudden, College Eye's EC-121s became capable of accurately discriminating low-flying MiGs from the myriad returns picked up by their long-range radars, and detecting these from a range out to 170 miles.

Project College Eye was further intensified and the QRC-248 made capable of reading transmissions from two additional Soviet transponders, the SRO-1 and the SOD-57 (Project Rivet Top). Combined with the addition of on-board Vietnamese linguists capable of listening to and translating the radio transmissions from North Vietnamese fighter-pilots in real time (Project Rivet Gym), suitably equipped EC-121s became the lynchpins in the US aerial warfare strategy.

Meanwhile, the miniaturized version of the QRC-248 - the APX-80 Combat Tree enemy IFF-interrogator - was installed into a handful of McDonnell Douglas F-4D Phantom II interceptors of the US Air Force. The fighters in question scored some of the most spectacular air combat victories in the Vietnam War of 1971-1972; they also suffered some of the most painful losses.

Telling a little-known story, yet of crucial importance for the flow of the air war over North Vietnam, College Eye provides rare insights into the development, operational deployment, and combat operations of a relatively small community of US airmen: a story about what eventually evolved into the ‘Mother of modern-day AWACS aircraft'.