Company G was part of the Marine Support Battalion (MarSptBn), a small group of Marines that supported the United States Navy in their cryptologic endeavors. Sabana Seca was and is a Navy base, specifically Naval Security Group Activity (NSGA), Sabana Seca. It was also known as U.S. Naval Communications Station, Sabana Seca (USNAVCOMMSTA). There was a separate company of guard Marines stationed there who provided security and sentry duty for the base. The base closed in 2003.
Our work spaces were a couple of miles away perhaps four or five miles from the Atlantic Ocean on the north central coast of Puerto Rico. There were two buildings, numbers 85 and 40, each separated by a couple of miles. We took a bus from the base to get there.
There were other "letter" companies like Company "G" around the world, usually on Navy bases. The school we attended to learn our occupation was a Navy school, a cryptology school.
Whereas the USMC total strength in 1965 was 190,213, there were less than 1,500 Marines who were in the Marine Support Battalion.
(Our tour of duty there was usually two years, although some stayed longer. The average number of Marines in Co G at any given time was approximately 46 to 50 Marines.)
We all had Top Secret clearances. Most if not all of the things we did have long since been declassified, as technology left what we used to do in the dust long ago. Of course there is still Morse Code and always will be, but its uses were far more common in the mid-1960s than now. Some of the equipment we used is now seen only in museums, alongside various Neanderthal exhibits. This is a little depressing, naturally. But we move on.
Around 1997 I began a search of former Co G Marines, locating perhaps 50 people. Before that, a lot of us had already kept in touch for some time.
Other Marines who stayed in for 20 years have remarked that the particular group at Co G was unique, (1964-1968) and was the best duty station and the best group of people that they ever encountered in all their years in the Corps.
One Marine describes the experience there as "magical".