to The COMSAT Legacy Project, Satellite Television Corporation (STC) Resource.
Once again, the Executives, Scientists and Engineers at COMSAT revolutionized the industry and worked through the legal,
regulatory, and technical hurdles that were required to pave the way for the Direct Broadcast Satellite (DBS) Industry.
In 1980 COMSAT formed Satellite Television Corporation (STC) to enter what was projected to be a $6 billion-a-year market.
Headed, by Irving Goldstein, who joined COMSAT in 1966, STC was slated to deliver television programming by satellite directly to small, 2-foot-diameter dish antennas at the home. The service was expected to attract more than 20 million customers, an undertaking that could ultimately reach $1 billion for COMSAT.
At the time, television was widely available in U.S. cities, with over-the-air channels from the three original TV networks and several cable channels (e.g., HBO). But in many of the outlying and rural areas, which were too far from cities to receive over-the-air television and where the laying of cable was not economically viable, television was often unavailable. That was STC's initial market, and the expectation was that the company would then develop exclusive programming that would attract subscribers in the cities and suburbs.
In December of 1980 STC filed with the Federal Communications Commission (FCC) an application to build and implement the system, which would be the first Direct Broadcast Satellite (DBS) service in the world.
Like cable, the service was by paid subscription, bringing 3 channels of television to the entire U.S. But its design was radically different from the satellite systems in use then to distribute television to cable companies using 20 – 30 foot ground antennas. Instead of low-power C-band satellites covering the whole U.S. or more, the STC satellites would operate at K band and have roughly 20 times more transmission power focused on time-zone-size areas, allowing the use of the small antennas at the home.
After some opposition from several parties (see one example here), the FCC application was granted and in October of 1982 STC contracted with RCA for the construction of the first 2 satellites, one to serve roughly the Eastern Time Zone and the other one roughly the Central Time Zone, with an option for 2 additional satellites to later serve the western U.S., Alaska and Hawaii. Each of the RCA-built satellites employed 3-axis stabilization with deployed solar array panels (rather than the more common spin-stabilization with body-mounted solar cells typically used on earlier communications satellites) and would be launched to geosynchronous orbit from the Kennedy Space Center either on the the Space Shuttle or on a Delta rocket.
Aside from the frequency band and the 200-watt transmitter powering each of the 3 television channels, two other features of the satellites were noteworthy. To pack maximum communications gear, the satellites did not carry the heavy batteries needed to operate the television channels during the brief (maximum 90 minutes) solar eclipses that ocurr for several days around the equinoxes; to minimize the impact of the outage on subscribers, each satellite would be stationed far west of its coverage area at one of the orbital slots which would be assigned to the U.S. at the Regional Area Radio Conference (RARC) in 1983, so that the outage would occur at around 3 AM for the subscriber. The other salient feature was that although both satellites would be identical, multi-beam antennas could be configured in orbit to serve either of the two coverage areas, roughly the Eastern Time Zone or roughly the Central Time Zone.
While the satellites were under construction, considerable work continued along several tracks. From a business standpoint, discussions accelerated with television programming providers and similar entities to find a programming mix that would attract subscribers to the new service. Technical work proceeded on encryption systems to ensure the signals could not be “robbed” by non-subscribers. In addition, High Definition Television (HDTV) was being developed worldwide to offer far more resolution and a wider aspect ratio (width-to-height ratio) than was offered by the NTSC, PAL and SECAM video formats available then; because DBS offered the opportunity for the first time to distribute HDTV nationwide, work was being done at Comsat Laboratories and elsewhere for the cost-effective transmission of HDTV by DBS (see the last technical paper in the list below). But by far the most important factor was the advances being made by consumer electronics firms working on the development of the home terminals, with their performance exhibiting great improvement almost on a monthly basis*.
Partway during the construction of the satellites, analyses showed that the performance improvements demonstrated and forecast for the home terminals, as mentioned above, were sufficient that acceptable signal quality could be delivered to the television set if the coverage area of each satellite was widened, from a single time zone to two time zones. Therefore, STC contracted with RCA for a change so that one satellite would serve roughly the eastern half of the U.S. while the other one would serve the remainder of the U.S., including Alaska and Hawaii. Again, both satellites would be identical, with the multi-beam antenna configurable in orbit to provide either service.
That change would not only cut in half the cost of the space segment (satellites and launches) needed for nationwide service but would increase revenues by allowing STC to serve clients in the western U.S., Alaska and Hawaii from the outset, rather than years later.
Despite these business-enhancing changes, Comsat subsequently decided to cancel the program, when the 2 satellites were almost finished. While several reasons have been offered for this, the most prevalent include the inability to find a suitable partner that would provide the attractive television programming required and because of uncertainty on whether the subscription service would be profitable in light of the roughly $660 million dollars of capital investments in the project.
An effort was made to sell the satellites to several overseas entities, with changes to the antennas to serve a different coverage
area, but the efforts failed and Comsat ended up writing off $400 million; those efforts in the UK were chronicled by the
In an ironic twist, RCA sold the 2 satellites to NHK with antenna modifications for DBS service in Japan, and both were lost due to
separate launch failures.
A sampling of
from Ernesto R. Martin is presented below. They range from descriptions of the STC overall system, to profit-seeking techniques for DBS systems, to high-definition television.
"The Impact of WARC-79 on the Broadcasting-Satellite Service"
. Co-author. Institute of Electrical and Electronic Engineers Transactions
on Electromagnetic Compatibility, Vol. EMC-23, No. 3, August 1981.
"A Direct Broadcast Satellite (DBS) Service for the U.S. System Description and Trade-offs"
. Presented at the AIAA Communications
Satellite Systems Conference, Orlando, Florida, March 1982. American Institute of Aeronautics and Astronautics Paper No.
"Satellite Television Corporation's DBS System". Presented at the IEEE 16th Annual EASCON
Conference, Washington, DC, September 1983.
"Satellite Television Corporation's DBS System - An Update". Presented at the AIAA
Communications Satellite Systems Conference, Orlando, Florida, March 1984. American Institute of Aeronautics and Astronautics
Paper No. 84-0664.
"DBS Systems - Perspectives From a Profit-Seeking Company"
, presented at the XXXVth International
Astronautics Federation Conference, Lausanne, Switzerland, October 1984, and published in Telecommunications Policy, Vol. 9, No.
4, Fall 1984.
"RCA's Direct Broadcast Satellites for STC".
Co-author. Presented at the XXXVth International
Astronautics Federation Conference, Lausanne, Switzerland, October 1984.
"Downlinks for DBS:
Design and Engineering Considerations"
. Co-author. Institute of Electrical and Electronic Engineers Selected Areas in
Communications, Vol. SAC-3, No. 1, January 1985.
"High Definition Television - A DBS Perspective", Institute of Electrical and Electronic Engineers
Journal on Selected Areas in Communications, Vol. SAC-3, No. 1, January 1985.
* The small-antenna home terminal receives and amplifies the relatively weak signals from the satellite. How well it does that depends largely on how little noise is added by the low-noise block converter (LNB) mounted on the antenna during this amplification. The use of gallium arsenide semiconductors in the LNB was being developed at the time, with impressive improvements in the performance of the home terminal.
Currently, there are 85
photos in this collection,
Steven L. Teller
COMSAT Legacy Archives
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