Continuing my reporting on the 17 October 2018 symposium on the Tet Offensive:
As I noted yesterday, I contributed to the signals intelligence forewarning of the Tet Offensive in two ways, even though I was not at NSA when the report and its ten follow-ups were issued.
The first action on my part was that I saw the country-wide offensive coming and urged NSA to alert U.S forces.
During the late summer and early fall of 1967, I was in the western highlands supporting U.S. forces there. From the intercept and analysis of North Vietnamese communications, I was able to tip off the 173rd Airborne Brigade and the 4th Infantry Division to the buildup of Vietnamese Communist forces in Kontum Province and their intent to attack us. The end result was the battle of Dak To.
As the battle was winding down, I moved south to the Bien Hoa area, just north of Saigon. Once there I saw the same enemy communications practices we had observed in the highlands. Signals intelligence units all over the country detected the same patterns. I realized that the North Vietnamese were planning simultaneous attacks nationwide and exhorted NSA to pull together all the data and report the battle preparations.
The result was the alert to all recipients of our reporting that a country-wide offensive was about to begin.