KU-BAND DISTRIBUTION OF TELEVISION PROGRAMMING FOR THE CABLE INDUSTRY PAUL A. HEIMBACH and GERALD S. KAPLAN HOME BOX OFFICE, INC. and RCA AMERICAN COMMUNICATIONS, INC. INTRODUCTION The success of Ku-band distribution requires the optimization of the Ku-band for satellite delivery of satellite system including satellite television programming has become performance, in orbit and ground accepted worldwide. Abroad, protection to insure continued European and Japanese satellite operation, and the frequency plan to systems are based on the Ku-band ensure maximum utilization of the frequency to take advantage of (1), orbital resouce. On the ground higher power signals, which result careful planning and operation of in a less costly ground segment, and the Ku-band receiving earth stations (2), relative freedom from RFI, is needed to insure superior quality which facilitates antenna siting. and reliable reception of the signal. In the United States, Ku-band has been selected for network television In July, 1986 subsidiaries of HBO program distribution and for the and RCA formed a joint venture establishment of nationwide called Crimson Satellite Associates satellite newsgathering services by to build, acquire, and launch a Ku­ several entities. It is also the band satellite called K3. Crimson preferred transmission technology also has the option to acquire and for VSAT networking to establish launch a second Ku-band satellite, private voice/data, transaction and called K4, and, subject to FCC video conferencing systems. approval, to co-locate it with K3. Launch of K3 is scheduled for Mid- By 1992 67 percent of the satellites 1989. world wide will be operating at Ku­ band. And of the 6 domestic U.S. An existing RCA Ku-band satellite, launches planned between now and Kl, serves to provide interim 1990, five are either Ku-band or capacity until 1989 and allows the hybrid. cable industry to build confidence in Ku-band distribution by providing The use of Ku-band for program a time to experiment and learn. distribution to CATV and SMATV Thereafter Kl will serve as an systems is an evolutionary process, integral component in the satellite not a revolutionary step. Ku-band system protection plan. distribution allows affiliates to serve subscribers considered WHY KU-BAND unreachable at C-band, eliminates the problems of C-band terrestrial The use of Ku-band for program interference encountered at some distribution to CATV and SMATV primary receive locations, provides systems is a natural step in our a 2nd totally redundant signal industry, as illustrated by distribution path thus protecting examining future satellite systems. against program disruption and, over the next 3 years, allows an A review of launch schedules reveals unprecedented increase in the that the next generation of efficient use of a satellite orbital satellites are predominately Ku slot and spectrum. satellites. 268-1987 NCTA Technical Papers Between now and 1992, 59 proposed In most cases, economical communications satellites are 1.8 meter Ku dishes for authorized for launch worldwide. Of rural cluster cable these, 52 will be Ku-band or Ku­ systems not yet receiving hybrids, six will be C-band and one satellite programming, (Italy's) will operate at another thereby providing new frequency. services to homes heretofore unreached by Between 1987 and 1990, Ariane has programmers. reservations or contracts to launch 32 communications satellites on 24 Ku earth stations costing rockets. Of these 32 satellites, approximately $1300 can be only one does not have a Ku-band used by operators to reach payloacr:- Thi~~scilpabl~_ _!?ct unpassed multi-family merits emphasis: Every units (SMATV) prior to an communications satellite launched urban cable build or in between now and 1990 will be K-band, lieu of long cable runs to save one. reach a rural pocket such as a trailer park or Ku-band has become the clear choice apartment complex. for future capacity for four important reasons: 2. Superior Protection Against Failure:---------------------- 1. Business Benefits to the Cable Ku-band offers the opportunity Industry: to create a superior level of The benefits of Ku-band stem protection from catastrophe that largely from its regulatory is cost-effective, flexible, and heritage. C-band satellites are adaptable to the evolving secondary users of a shared­ business environment. The frequency assignment and objective is to maintain the consequently must not interfere business with minimal disruption with the terrestrial microwave to program continuity or the links also using the spectrum. installed receiving system. The interference is held to a minimum by operating C-band Protection at Ku-band makes satellites at low power levels. possible a protection Also, reception of C-band configuration ensuring minimum signals can be difficult or disruption of service by impossible because of eliminating the need to repaint interference from these same earth stations at a new terrestrial microwave links. satellite or disperse programming across several The Ku-band satellite service, satellites in the event of on the other hand, is a primary catastropic failure. user and does not need to protect any other radio service. Unlike any protection plan at Consequently, Ku satellites can C-band, Ku-band protection is be more powerful than those achieved by on-board redundancy, using C-band, permitting the use an in-orbit spare satellite and of smaller, less expensive a ground spare satellite. The equipment to receive the signal. growing base of Ku satellites This naturally provides business means the cost of protection is benefits to both programmers and reduced to each user while the cable affiliates, particularly number of C-band systems as they look to serve areas not decrease, the cost of protection yet passed by cable plant. will be shared by fewer users, These business benefits include: and thus cost to each user will increase. 0 The ability to situate a Ku earth station at an 3. Technical Evolution: urban headend regardless The-early~-band satellites of the presence of were primarily designed for the terrestrial microwave transmission of high volume signals, which will voice and data traffic from facilitate construction as point A to point B using the major urban markets relatively large antennas. Ku are cabled. satellites being constructed today and in the future will be 1987 NCTA Technical Papers-269 more sui ted to the predominant to 12.2 GHz band on the downlink. uses of satellite capacity Each satellite includes sixteen video and point-to-multipoint transponders with 47 watt TWTAs (60 small dish data transmission. watts with FCC approval). Eight of the transponders will be Ku-band satellite systems have horizontally polarized and eight been operational since 1980. will be vertically polarized. For The technology and performance high reliability, these sixteen characteristics have been transponders are protected by a studied and well-defined. The total of six spare TWTAs on board past 7 years of experience the satellite. allows this new generation of Ku-band satellite to overcome The transponders will be fully many of the problems experienced protected against eclipse outage. in the past. This lnsures full operation and power for 24 hours a day, 365 days a The early problems of degraded year for the 10 year design life of performance due to rain the satellite. attentuation exhibited in the first generation Ku satellites The high power available from the have been overcome through the TWTAs on board the satellite will be development of more powerful directed to the earth in one of satellites capable of providing three modes that are reconfigurable increased signal margin. Using on orbit by ground command. These the antenna sizes our industry modes will allow any individual employs, rain no longer degrades transponder to be configured as a service for any significant CONUS beam or an East beam or a West time. beam. This allows the entire transponder power to be concentrated 4. Channel Capacity: in the areas of the country where Only--24--channels of video the signal is desired. Selectable programming can be transmitted coverage ensures that each from each C-band orbital transponder has flexibility for the location. Therefore, headends user and can readily accomodate are now "antenna farms" with an varying traffic usage patterns. ever-increasing number of dishes looking at a variety of C-band An EIRP pattern showing the minimum satellites. The proposed EIRP valves for 60 watt transponders channelization plan of the expected for each of the transponder Crimson Satellite Associates modes is shown in Figures 1, 2, and Ku-band satellite system would 3. The East beam provides coverage allow each TVRO to receive a to the Eastern and Central time total of 32 program channels zones while the West beam covers the from a single orbital location. Pacific and Mountain time zones. The CONUS mode covers the 4 8 contigious states. Hawaii is CHARACTERISTICS OF THE K3 and K4 covered in the West beam and CONUS SATELLITES modes. Two video signals per transponder can be accommodated, The present FCC rules governing Ku­ allowing up to 32 television band satellites operating in the FSS channels to be distributed by one band allow more flexibility in satellite. satellite design: i.e. higher power densities are permitted (compared Another innovative feature of this with C-band) since interference with satellite is the on board dynamic terrestrial networks is not a limiter amplifiers (DLA). When the problem. DLA is operating in the limiter mode, the transponder output is The design of the K3 and K4 maintained at full downlink power satellites incorporate many advanced even when the uplink signal fades. features that will enable the high This insures that the overall video performance requirements of the CATV signal to noise ratio will be and SMATV industry to be met across affected minimally by uplink fades the country.