The SAGE building at McGuire Air Force Base, circa 1958. On the far left are cooling towers for the generators located in the (low) middle building. The “cube” has four floors, with air conditioning and wiring on the ground, the computers on the second floor, offices on the third and the combat center on top.
Research to improve military communication continued apace following World War II. Many government entities including the National Bureau of Standards contributed to research, as did many corporations seeking government contracts, including David Sarnoff’s RCA. Effective radio communication was essential in the year-long Berlin Airlift that involved both military and civilian pilots flying cargo along narrow flight paths.
Korean War (1950-1953) communications generally used equipment from and followed patterns set in World War II, though television brought a delayed view of the war to home viewers. Much World War II communications equipment had been properly moth-balled and stockpiled in Japan in 1949 to 1950. American forces lived off this equipment during the early, desperate months of the Korean War. Korea’s climatic extremes, mountainous terrain, and lack of good roads greatly complicated communications. The Army Signal Corps depended heavily on very high frequency (VHF) radios to span the long distances, while on the ground signal soldiers often used water buffalo to string wire. After truce talks began in mid-1951, the front became largely static, and wire and radio operations more routine. Paradoxically, the Army Signal Corps also tried carrier pigeons, though they proved vulnerable to Korean hawks.
Seeds of the third military communications revolution were laid in this period. Development of the transistor at the Bell Telephone Laboratories in the late 1940s began what would become the solid state electronics revolution in communications. The notion of solid state electronics had been suggested in principle in the early 1950s and was of central interest to the armed services. If workable, such systems promised huge benefits of special value to military applications-robustness, lower weight and power requirements, and far greater capacity. The U. S. Air Force contracted with Westinghouse in 1959 to experiment with “molecular electronics.” The Signal Corps was already developing a “micro-module” project to shrink component size across a variety of military needs. Research and development work was underway at many companies, usually funded by Air Force or Navy contracts. Over the next dozen years reliance on fragile vacuum tubes was swept away in the face of more durable transistor circuits.
That revolution was substantially boosted with the integrated circuit invented independently by Jack Kilby and Robert Noyce in 1959. They both determined that squeezing all elements of an electrical circuit-transistors, connections, and other electronic devices-onto a tiny silicon chip could be accomplished and would save considerable space while speeding up signal processing speed. Eliminating the need for individually hand-wired connections between the transistors and other elements would also greatly increase circuit reliability. The potential was huge. These tiny means of powering electronic devices aided the drive to component miniaturization that lay behind the development of ballistic missiles and computers. By the 1960s, Silicon Valley was fast developing, funded in part by growing military procurement of information technology (IT).
Working with the U. S. Air Force, the Army Signal Corps launched the world’s first communications satellite in December 1958. Two years later it cooperated with the Weather Bureau and others to develop the first weather satellite.
Communication links proved vital in the short but intense 1962 Cuban Missile Crisis. By the late 1960s, communications satellites had begun to allow instantaneous communication from central military commands to remote parts of the world. For more local areas, intelligence ships bristled with communication antennas of all sorts, but as the Liberty affair proved, they were vulnerable to attack or takeover. China, India, and Pakistan developed increasingly sophisticated systems of military communications, as did such smaller countries as the Netherlands. British Commonwealth nations including Canada, Australia, New Zealand, and South Africa all honed their communications systems, many of which dated to before World War I.
In 1960 the U. S. Department of Defense put its various communication systems under unified control to become a single Defense Communications System, managed by the Defense Communications Agency. In October 1962, a concept of operations for a World Wide Military Command and Control System (WWMCCS) sought to integrate all of these systems. Operating from 1963 to 1996, the WWMCCS was a centralized system to access information and communicate directives to American military forces. Labeled a “loosely knit confederation” of systems, WWMCCS lacked the centralized design, procurement, and operations needed to perform its mission successfully on a consistent basis. In 1967, the packet-switched DARPANET began to connect a growing number of academic and defense research establishments- it would operate for more than two decades. DARPANET (which would evolve into the Internet in the mid-1990s) used computer protocols to interconnect different types of equipment and software.
The Vietnam War (1959-1975) saw the peak of analog military communications potential. Airmobile communications closely tied ground troops to their air support. For the first time, high-quality commercial communications became available to the soldier in the field. On the tactical level, new transistorized combat radios enabled infantry, armor, and artillery to communicate directly with each other. For strategic purposes, the Signal Corps employed such sophisticated techniques as microwave relay and tropospheric scatter. The American Phu Lam communications hub in South Vietnam processed growing amounts of military information by the early 1970s.
Priority access over all systems-including the first communication satellite links-was assigned to command-and-control and intelligence users, while logistics, personnel, and other less urgent matters were carried on slower radio-teletype links until the introduction of first-generation digital communications (the automatic digital network, or AUTODIN, system) in 1968. After American withdrawal from Vietnam in 1973, shortages of skilled technicians and spare parts rendered some 40 percent of the U. S.-supplied communications equipment held by South Vietnam forces inoperable. As a result, increasing quantities of their classified messages were also carried by courier until the war’s end in 1975.
North Vietnamese and Viet Cong forces relied on a combination of old and newer means of communication, primarily paper orders carried by couriers as well as Chinese and Soviet radio equipment. U. S. intelligence estimates showed that signals personnel comprised less than 5 percent of total enemy unit strength, compared with up to 20 percent in American ground forces. Security protocols included use of prearranged transmission times, spectrum frequency changes, concise messaging, and one-way communications. During large operations, minimal use was made of radios; troops relied instead on traditional couriers, fire and flame, lights and beacons, and music signals (whistles and the like).
Unlike in earlier wars, tactical military and larger political concerns were very closely intertwined, often confusing propaganda messages and effects. Broadcasts, loudspeaker announcements, and leaflets were the primary means of transmitting messages against the Viet Cong and North Vietnamese throughout the fighting areas. But both enemy forces were far more complex targets (they were more committed to their fighting role than earlier opponents) in what many considered a civil war. The way in which the war ended in Vietnam had a debilitating impact on the practice of military propaganda and psychological warfare, and their importance sharply declined in the American military services for several years.
Throughout the 1945-1990 Cold War, both the United States and the Soviet Union spent enormous sums on weapons, communications security, and counterintelligence efforts, though often with only limited result. As but two examples of expensive means of air defense communications, the Airborne Warning and Control System (AWACS) and Semi-Automatic Ground Environment (SAGE) system pushed analog technology to the edge of what was attainable. Security of American military transmissions fell to the Signals Security Agency, soon to become the huge National Security Agency based at Fort Meade, located north of Washington.