The AN/TPS-25 “Tipsy 25” Battlefield Ground Surveillance Radar system was an incredible piece of equipment for its time. It was so effective that it was still in use during Gulf 1. The Doppler feature was probably the most significant part of the system. It allowed a skilled operator to identify the target via audio feedback. Moving things created a wavy “flaky” image on the otherwise green, straight horizontal line at the bottom of the small scope. Moving the flaky stuff into a 1/4″ wide range gate brought the Doppler feature into play. This was vitally important. Wind-blown vegetation could create the flaky image as well as moving persons. The swinging arms and legs of personnel created very distinct whooshing-like sounds in the radar audio system. An experienced operator could easily distinguish between the wind-blown leaves and moving personnel.
Once we detected and identified a target, we could determine the strength (number of people) and direction of movement, plus the map coordinates. We could count on the enemy troop columns to move at pretty much the same pace and direction for a few minutes or more, so we could fairly accurately predict their location in say, 8 minutes, the usual amount of time it took to get rounds on target. And of course from there, we could call adjustments if necessary. More often than not, we put it right between their horns.
Our primary AO (Area of Operation) was near the Cambodian border with focus on two distinct areas known as the “Angel’s Wing” and “Parrot’s Beak.” Each border shape resembled their namesake, protruding into Vietnam. We spent most of our time at FSB’s (Fire Support Base) within a few miles of the border. We often observed enemy movement just across the border. Obviously, these were staging areas for enemy soldiers and equipment, just before they crossed into Vietnam during the night. We were within rocket range. They could shoot at us, but we weren’t allowed to shoot at them until they crossed the border. What a crazy war.
Each of our 5-man team pulled 2 shifts per night of about 1.5 hours each. That may not seem very long, but I can assure you that it is easy to start seeing and hearing things not long after that. We needed a break.
We kept a logbook at arm’s reach on the left shelf in the cramped radar van. On our right was a PRC-25 radio, complete with a magic KY-38 encoder/decoder unit. We reset the codes every night at midnight. As the SRO (Senior Radar Operator) and only person in the crowd with a secret clearance, I had to sign for the encoder/decoder box and also for the weekly new code booklet. I kept it on a string around my neck. I chained and locked the encoder/decoder unit to the van. I burned the previous nights code page, with a witness. I almost felt important.
Some of the guys on our team got pretty excited during a fire mission. Perhaps Jerry, a draftee, was the most enthusiastic of the bunch. He was a darned good operator and did his best to detect targets. He’d gleefully point to his entries in the logbook the next morning with great excitement. The rest of us got pretty excited too when we completed successful missions, but probably didn’t make such a big deal out of it. But no matter. The point was, as a team, we were stopping a very significant amount of enemy infiltration along the Cambodian border from the Ho Chi Minh Trail. Not only did we increase our chances of surviving, I’m sure we made a positive difference for a lot of our buddies in the area. All of us are very proud of what we did. We had a non-glorious job; a job that is not well known and at best, very misunderstood. This is my attempt to change that perspective.