d. In any event, the bandwidth of present satellite receivers is great enough to accommodate the use of
spread-spectrum antijam techniques. Such antijam techniques are very effective, even in the face of heavy
4. Flexibility. Vehicle-mounted satellite ground-station equipment can be flown to remote areas and placed in
operation in a matter of hours. Once these stations are operational, long-distance communications can be
established with any other satellite ground station within sight of the satellite.
LEARNING EVENT 5: APPLICATION TO THE DEFENSE COMMUNICATIONS SYSTEM
1. The Defense Communications System.
a. The DCS is a communications network established by order of the DoD and placed under the direction
of the Defense Information Security Agency (DISA). The mission of the DISA is to ensure the DCS will be so
established, improved, and operated as to meet the long-distance, point-to-point telecommunications
requirements of the DoD and other governmental agencies as directed.
b. The DCS is a unified communications system that provides the long-distance, point-to-point
telecommunication requirements of the DoD. No other facilities are authorized for this purpose. The DCS
provides strategic communications facilities for command, operations, intelligence, weather, logistics, and
administrative purposes. It provides the quality and quantity of communications capabilities required for these
c. The DCS network consists of switching centers located in various areas around the world and the links
interconnecting them. Individual service units need only provide communications to the nearest switching
center to become network subscribers and have access through the network to the entire system.
2. Satellite application.
a. Satellite communications form part of the long-distance links between the switching centers. These
links employ the satellites in addition to other firms of existing communications media-HF radio, tropospheric
scatter, ionospheric scatter, landline, cable, and LOS microwave. They provide added capacity between various
points in the network and, since the satellite links continue in operation under conditions that will render other
media inoperable, they provide the important reliability factor necessary to military communications.
b. As the techniques of satellite communications evolve and are perfected, satellite communications can be
expected to provide the major part of all intercontinental links in the DCS. Their particular advantages in terms
of flexibility and survivability, which increase dramatically as the number of satellites in use is increased, will
predictably establish communications satellites as a major factor in the system.