LEARNING EVENT 7: APPLICATIONS OF SATELLITE COMMUNICATIONS
1. Transoceanic live television. Military communications satellites will probably not be used for regular
television broadcasts. However, in the event that commercial communications satellites are not in position to
cover important public events, military satellites may be pressed into service for television relay.
2. Commercial communications. There is a definite increasing trend on the part of business interests to use
computers in their operations. Machine-to-machine communications are now used regularly within continental
limits. Satellites have extended this type of communications to other continents and increased efficiency of
business using transoceanic digital data communications.
3. Telephone communications. Worldwide telephone communications have approached reality with the
introduction of satellite communications. The inhabitants of remote regions are no longer denied the benefits of
modern technological breakthroughs in communications. The vast expense of constructing and maintaining
telephone lines over inaccessible terrain will be largely eliminated by using communications satellites. The
only additional need will be a suitable ground terminal placed in an advantageous position.
4. Direct-distance dialing. Direct-distance-dial telephone communications systems are being extended on a
worldwide basis. The short dialing pulses used on these systems create many technical problems that are
difficult to solve when using existing long-distance communications facilities. The large values of line
constants (inductance and capacitance) in undersea telephone cables cause serious distortion of the dialing
pulses. Moreover, the noise, fading, and interference problems on the long-distance HF radio circuits cause
many dialing inaccuracies. Designers of direct-distance-link telephonic communications systems are therefore
looking toward the utilization of communications satellites to satisfy their needs. Experience with
communications satellites has proved the received signal to be admirably suited to carry direct-dialing pulses.
The received signal from a satellite is normally stable and relatively free from noise. Further, the absence of
large values of inductance and capacitance assures comparative freedom from pulse-length distortion.
5. Other applications. As satellite communications come into practical use, other applications will be found
which have not been conceived at the present time. Space communications technology has advanced at a very
rapid rate and is expected to continue to advance. Therefore, it is reasonable to assume that many new and
startling applications can be expected within the near future.
SS0031
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