In March 1967, Big Eye was renamed College Eye Task Force (CETF)and relocated at Ubon Royal Thai Air Force Base.
Because of the complexity of the aircraft and its systems along with the large support group it required, CETF was not welcome at the relatively small Thai bases.
It moved to Udon RTAFB in July and to its final station at Korat RTAFB in October 1967.
Seven of 26 EC-121s deployed from Otis AFB and arrived at Korat, on the 19th.

From April 1965 to early 1966 and beginning again in late 1967, the EC-121Ds also controlled a flight of MiGCAP fighters for unarmed support aircraft operating over the Tonkin Gulf.
The EC-121Ds also served as an airborne communications relay center for strike aircraft to transmit mission results and position reports to  Danang Air Control Center; directed operations of fighter escorts, MiGCAPs, Lockheed C-130 Hercules flare ships and A-26 strike aircraft along the North Vietnamese-Laotian border; provided radar and navigational assistance for Combat Search and Rescue missions; and assisted fighters in finding tankers for emergency refuelling.

The government of China in May 1966, formally protested an incursion by a Republic F-105 Thunderchief pursuing a North Vietnamese MiG it subsequently shot down 25 miles inside Chinese territory.
A US board of inquiry recommended that College Eye also had to monitor the "no-fly zone" inside the North Vietnamese border with China, to provide alerts to US aircraft nearing the buffer zone and to report border crossing violations by US aircraft.
This could not be done from the Gulf so a third orbit, Ethan Charlie, was created in Laos.
After tests in June and August, regular missions began 24 August.
There were not enough EC-121s or crews to support 3 orbits twice daily, so the Laotian orbit was only flown every third day, with Ethan Bravo missions canceled on those days.
After 13 October 1966, the Charlie orbit was flown every day and the Bravo orbit suspended altogether.
In April 1967, 4 more EC-121s were deployed, 2 to Thailand on 29 May, making for a total strength of 3 College Eyes in Taiwan and 6 in Thailand.

In April 1967, USAF began fitting its entire EC-121 fleet with QRC-248 IFF transponder interrogators.
 QRC-248 had been developed to follow Soviet -export aircraft flown by the Cuban Air Force.
The SRO-2 transponders installed in Soviet export MiGs enabled Cuban ground-controlled interception (GCI) radars to identify and control their fighters.
A testbed EC-121 called Quick Look had flown with College Eye in January 1967 to test QRC-248 and found that North Vietnamese MiGs used the same transponder!
QRC-248 accurately discriminated MiG radar returns from the myriad returns picked up during a mission and extended the range of low-altitude detection to more than 175 miles, covering virtually all important North Vietnamese target areas.

By May, all College Eyes had been fitted with QRC-248.
Ethan Bravo's mission was changed from that of a backup for Ethan Alpha to being the primary QRC-248 listener.
However College Eye was prohibited by the Joint Chiefs of Staff from actively "interrogating" MiG transponders, following a National Security Agency security policy protecting its "intelligence sources" (of which the QRC-248 was one) and thus was restricted to waiting for North Vietnamese GCI to interrogate its aircraft.
QRC-248 began regular use in July 1967, but by then North Vietnam's MiG force, which had suffered serious losses in May, had suspended its combat ops.

In the last week of August, however, after a period of intensive training and revision of tactics, the MiGs began engaging US strike forces again, scoring a number of kills.
Then Seventh Air Force finally obtained permission for the new Ethan Bravo mission EC-121 to actively interrogate with QRC-248 on 6 October.
By 4 December, its success outweighed any value in flying the Ethan Alpha orbit, which was discontinued until July 1972.

On 1 March 1968, College Eye callsigns changed to Ethan 01, 02, 03 and 04 in conformity with USAF SOP's.
Ethan 03 (Laotian orbit) began "positive control" (a
In March 1967, Big Eye was renamed College Eye Task Force (CETF)and relocated at Ubon Royal Thai Air Force Base. Because of the complexity of the aircraft and its systems along with the large support group it required, CETF was not welcome at the relatively small Thai bases. It moved to Udon RTAFB in July and to its final station at Korat RTAFB in October 1967. Seven of 26 EC-121s deployed from Otis AFB and arrived at Korat, on the 19th.
From April 1965 to early 1966 and beginning again in late 1967, the EC-121Ds also controlled a flight of MiGCAP fighters for unarmed support aircraft operating over the Tonkin Gulf. The EC-121Ds also served as an airborne communications relay center for strike aircraft to transmit mission results and position reports to  Danang Air Control Center; directed operations of fighter escorts, MiGCAPs, Lockheed C-130 Hercules flare ships and A-26 strike aircraft along the North Vietnamese-Laotian border; provided radar and navigational assistance for Combat Search and Rescue missions; and assisted fighters in finding tankers for emergency refuelling.
The government of China in May 1966, formally protested an incursion by a Republic F-105 Thunderchief pursuing a North Vietnamese MiG it subsequently shot down 25 miles inside Chinese territory. A US board of inquiry recommended that College Eye also had to monitor the "no-fly zone" inside the North Vietnamese border with China, to provide alerts to US aircraft nearing the buffer zone and to report border crossing violations by US aircraft. This could not be done from the Gulf so a third orbit, Ethan Charlie, was created in Laos. After tests in June and August, regular missions began 24 August. There were not enough EC-121s or crews to support 3 orbits twice daily, so the Laotian orbit was only flown every third day, with Ethan Bravo missions canceled on those days. After 13 October 1966, the Charlie orbit was flown every day and the Bravo orbit suspended altogether. In April 1967, 4 more EC-121s were deployed, 2 to Thailand on 29 May, making for a total strength of 3 College Eyes in Taiwan and 6 in Thailand.
In April 1967, USAF began fitting its entire EC-121 fleet with QRC-248 IFF transponder interrogators.  QRC-248 had been developed to follow Soviet -export aircraft flown by the Cuban Air Force. The SRO-2 transponders installed in Soviet export MiGs enabled Cuban ground-controlled interception (GCI) radars to identify and control their fighters. A testbed EC-121 called Quick Look had flown with College Eye in January 1967 to test QRC-248 and found that North Vietnamese MiGs used the same transponder! QRC-248 accurately discriminated MiG radar returns from the myriad returns picked up during a mission and extended the range of low-altitude detection to more than 175 miles, covering virtually all important North Vietnamese target areas.
By May, all College Eyes had been fitted with QRC-248. Ethan Bravo's mission was changed from that of a backup for Ethan Alpha to being the primary QRC-248 listener. However College Eye was prohibited by the Joint Chiefs of Staff from actively "interrogating" MiG transponders, following a National Security Agency security policy protecting its "intelligence sources" (of which the QRC-248 was one) and thus was restricted to waiting for North Vietnamese GCI to interrogate its aircraft. QRC-248 began regular use in July 1967, but by then North Vietnam's MiG force, which had suffered serious losses in May, had suspended its combat ops.
In the last week of August, however, after a period of intensive training and revision of tactics, the MiGs began engaging US strike forces again, scoring a number of kills. Then Seventh Air Force finally obtained permission for the new Ethan Bravo mission EC-121 to actively interrogate with QRC-248 on 6 October. By 4 December, its success outweighed any value in flying the Ethan Alpha orbit, which was discontinued until July 1972.
On 1 March 1968, College Eye callsigns changed to Ethan 01, 02, 03 and 04 in conformity with USAF SOP's. Ethan 03 (Laotian orbit) began "positive control" (a
Lockheed EC-121 Warning Star