CABLE SATELLITES : THE NEXT GENERATION Issues Facing Cable Operators and Programmers

Robert Zitter Home Box Office, Inc.

A development that will impact the ABSTRACT cable industry is the FCC mandate to phase-in a uniform 2-degree spacing The deployment of next-generation between U.S. domestic satellites. The satellites in compliance with the FCC's intent of the plan is to alleviate uniform 2-degree spacing plan, together overcrowding in the U.S. orbital arc. It with the movement of cable times the deployment of next generation programming, will occur during the next satellites with improvements in ground two years. A discussion of the transition station receiving characteristics in order scenario, the technical differences in the to control the ensuing increase in new satellites, and ground station adjacent satellite interference. requirements reveals that Cable TV and SMATV facilities will require This paper discusses the satellite reconfiguration and in some cases and orbital changes that are expected to replacement may be necessary. The occur during the next two years, and satellite movement and programming presents some critical issues and transfers in the early nineties compel the challenges facing satellite programmers cable industry to examine the future and cable operators . performance of existing facilities.

o Time of Replacements

In the early days, 4-degrees of separation within the two segments o Introduction assigned to U.S. domestic communication satellites -- 70 to I 04 C-Band satellites have become a degrees and 117 to 143 degrees West reliable means of delivery for cable Longitude (oWL) -- consisting of 15 television programs and have played an satellite slots were found adequate. (The important role in the phenomenal growth central portion from 104 o to 117 o has of the industry. We have seen numerous been reserved for Canadian and Mexican operational, technical and regulatory satellites.) But as the popularity and changes together with technological importance of satellite delivered services advances in satellite and ground station increased, the separation provided in the equipment that led to significant usable orbital arc for U.S. domestic reduction in overall costs. The cable satellites was found inadequate for industry has demonstrated its ability to planned spacecrafts. successfully deal with such changes over the years.

188-1991 NCTA Technical Papers Hence, in 1983, the FCC adopted most of the technical, regulatory and a plan to essentially double the number economic developments that we of orbiting domestic communications experienced during the past decade. satellites by gradually reducing the In the early nineties, Alascom, Figure 1. Next Generation Satellites AT&T, Conte!, GE Americom, GTE Spacenet and Hughes communications CARRIER/ FREQ ORBIT LAUNCH will construct and launch next-generation SATELLITE BAND DATE satellites as shown in Figure 1. The cable ALASCOM industry has committed to basically two Aurora II satellite vendors -- Hughes and GE (Satcom CS) C 139 May 1991 AT&T Americom --involving four satellites_ HBO Telstar 401 C 97 May 1993 and Turner Broadcasting are anchoring Telstar 402 C/K 89 Mar 1994 CONTELASC Hughes' Galaxy V and Galaxy IR, while ASCII C/K 101 Apr 1991 Viacom Networks and a group of other ASC1R C/K 129 Sep 1993 programmers including H BO have GEAMERICOM chosen Satcom C3 and Satcom C4. ~:!~~~ g~ : .!\:1!!§. :=::1\11\ !l:!i:,:::i~i::::,: .·:::::~t.V.,~~~ :::::: ~ Satcom C1 C 137 Nov 1990 • Satcom H1 C/K 79 1994 GTE SPACENET GStar 4 K 64 Nov 1990 Spacenet 1R C/K 103 May 1993 Spacenet 2R C/K 69 Sep 1993 o TRANSITION GStar1R K 121 Jun 1994 HUGHES SBS 6 K 72 Oct 1990 The preparations for launching the Galaxy v =:::::: (/C :=:::: ;-::':)2S.' ::::: ·''·''''''tool::: o next generation cable satellites and the Galaxy 1R \)/: C ;:;:;::: A~:: ;: :::: :: ·))~~~::·\' o accompanying movement of Galaxy VII C 91 1992 Galaxy VI C 91 Oct 1990 • programming actually began in 1988, as Galaxy IV C/K 99 1992 Galaxy I and Satcom 3R approached Galaxy IIIR C 95 1994 NATIONAL EXCHANGE their designed end-of-life terms. Spotnet I C/K 93 Mar 1993 Recognizing that approximately three Spotnet II C/K 127 Sep 1993 years of lead time is required to design,

o Cable Satellites construct and launch satellites, the FCC _ • In-orbit Backup for Cable Satellites and satellite vendors developed a transition strategy with the goals of spacing between satellites, so that over ensuring uninterrupted service and approximately ten years, a uniform 2- minimize inconvenience to users. degree spacing would be achieved. This evolutionary approach was chosen The transition timetable for the because: It prevented early obsolescence deployment of satellites is illustrated in of existing satellites; it granted Figure 2_ Note that Satcom 3R (131 OWL) manufacturers sufficient time to design has been temporarily replaced by and construct antennas that can better Satcom 1R in 1991 and will remain there discriminate between adjacent satellites; until Satcom C3 (131 ° WL) becomes and, it permitted cable operators to operational in 1993. Satcom 1R (originally amortize their existing facilities. The at 139 o) moved its traffic to Satcom C 1 FCC's 2-degree spacing plan guided (139°W) and then Satcom IR was

1991 NCTA Technical Papers-189 repositioned to 131 oW to take over traffic unable to be used in the 2-degree from the retiring Satcom 3R (131 OW). spacing plan can be replaced or new Satcom C3 will take over when antennas with better specifications can be installed.

1991 1993 1994 1995 2004

(139) The move will most likely occur SATCOM C1 during a 7-day period, beginning on (137) Monday. To minimize service disruptions, SATCOM C4 (135) the bulk of the satellite movement would occur on weekdays. Only one or two GALAXY I (134-133) repainting procedures would be normally

SATCOM 3R required, depending on antenna size, (131) antenna directivity and system noise GALAXY V margin. (125)

GALAXY III (93. 5) Galaxy V (125 oWL) will be launched during the last quarter of 1991 GALAXY VI (91) and will become operational in early 1992. Fig. 2 Deployment of Next Generation Cable Satellites In the middle of 1993, Galaxy IR (133 ° WL) will replace the retiring co­ located Galaxy I (133 oWL) and remain there until its end of life in 2005 Satcom 1R retires. Although the changeover and spacecraft maneuvers Another cable satellite, Galaxy Ill between Satcom 3R, 1R and C3 are (93.5 oWL) will remain in its current orbital complicated, most transfer activities will location until its end of life in 1995. The be transparent to cable operators broken line in Figure 2 depicts a possible because antenna repainting would not be transition of programming from Galaxy Ill required. Minor polarization skew to other satellites as transponder leases adjustments needed to be performed expire in 1993. when Satcom IR was relocated due to the finalization of the orthogonal While these transfers are interleaving of adjacent satellites, which happening, both GE Americom and was not supported by Satcom 3R. Hughes will maintain two C-Band fleet spare satellites Satcom C1 (137 ° WL) and Galaxy I will be moved by one Galaxy VI (91 OWL) respectively. These in­ degree from 134 oWL to 133 oWL during orbit spare satellites were launched in May or June of 1991 in compliance with advance (1990) to provide restoration in the FCC uniform 2-degree spacing plan. case of launch failures of the four primary This movement will require antenna cable satellites. The spare satellites will repainting. The schedule will be contain pre-emptible programming to announced to the industry ahead of time accommodate protected cable services in so that multiple-beam antenna feeds the event of fleet satellite failures.

190-1991 NCTA Technical Papers Figure 3. PROGRAMMING ON CURRENT AND NEXT GENERATION SATELLITES (January 1991)

PROGRAMMING ON CURRENT SATB.lJTES POSSIBLE PROGRAMMING ON NEXT GENERATION SATEUJTES

SATCOM C4 ~ ~TCOMIR GAlAXY Ill GALAXYV GALAXY IR ~TCOMC3 (Formerly lilA) HBO E HBO E Showtime Nickelodeon HBO E HBOW MTVE TBS Cinemax E Movie Channel C-SPAN 2 Comedy Channel BET MTVW TNT Turner Bdcst VH·1 ave Headline News Request TV 1 Nick E Headline News Disney W E! Nustar ESPN USAW HA! CNN USAW ave Discovery Showtime W CNBC Viewer's Chce 1 ESPN ESPN A&EW Prevue Guide TMCW Ufetime W Viewer's Chce 2 USA E Eternal Word C-SPAN 1 Family Chan W Disney E TNT (to G1 3/91) Weather Cha A&E E Univision Family Chan E Sci-fi Chan A&E Cinemax W C-Span II Disney E Nostalgia Home Shopping 1 Home Shop 2 TNT (3/91) Bravo VH-1 Mind Ext. U Group W Learning Channel Viewer's Choice CNN El Ufetime E FNN Inspirational Ufetime E Ufetime W Cinemax E Learning Channel C-SPAN I BET Viewer's Choice WOR-TV WTBS FNN/Source NickW Monitor Channel Weather Channel Showtime E AMC/AVN Family Net Group W-Nashville Cinemax W TMC E Request TV 2 Nustar United Video-WGN HBOW USA E Fashion MEU Trin1ty Disney W TBN EWTN Viacom Discovery jvideo Mall Shop TV CVN TNN Unlvision HSN Family Channel ave ACTS WGN VISN CVSJPPV ESPN Blackout CNN/feeds ESPN Blackout CMTV Travel WWOR Home Shop 2 Inspirational lnspirational(4/91) Galavision

o Where will programming windup? encouraged to keep in touch with programmers to keep abreast with As the new fleets of next developments and to determine the exact generation satellites become fully timing and location of simultaneous operational, the programming lineup will feeds. It is imperative for cable operators transition as well. The transfer of to find out where the programs currently programming will take place in 1992 and carried will wind up. In order to determine 1993. how the transition will impact individual HBO and Turner Broadcasting, cable system operation, you should joined by USA, ESPN, Disney and others become familiar with the future satellite will anchor Galaxy V and Galaxy IR. plans of each programmer. Viacom, joined by other programmers will anchor Satcom C3 and Satcom C4. HBO and Cinemax West feeds will be on Satcom C3. After the switchover to the 0 2° Spacing-Timing and next generation satellites, the cable Implications programming lineup will most likely appear as in Figure 3. The process of retiring satellites and launching new ones has been To minimize service interruptions, carefully planned to ensure a smooth the programming networks will most transition. Actually, the space segment likely dual-feed each of their services for procedures have already started. For a certain period. Cable operators are example, the two spare in-orbit satellites

1991 NCTA Technical Papers-191 have already been launched and now Smaller diameter antennas such operational; new generation satellites are as those serving SMA1V or smaller cable now either approaching final design systems are particularly susceptible to stages or under construction; and, some increased interference from adjacent spacecraft maneuvers have been satellites due to their wider beamwidths. accomplished. There are more activities that are planned to take place during the Other antenna configurations such next two years, and more ground as those having multiple feed horns segment activities can be expected. could be seriously affected if each individual C-Band feedhorns can not be The eventual reduction of satellite physically moved closer to one another. spacing to two degrees will require To correct this problem, some antenna careful examination of several ground manufacturers devised new assemblies segment technical issues. Of utmost and/or feedhorn designs that are claimed importance is the earth station's ability to to function under the 2-degree spacing avoid interference from signals coming plan. from undesired adjacent satellites. The parameters that affect interference are: In some cases, parabolic antennas Satellite transmit power (EIRP), antenna that were retrofitted with dual or triple directivity, receiver sensitivities, signal feeds might have to return to single feed formats, type of modulation, frequency configurations. offset, IF Bandwidth and filtering techniques. Of these, satellite EIRP and There is still sufficient time to antenna directivity are major factors that identify potential problems and deal with determine acceptable or objectional them accordingly. levels of interference.

The majority of C-Band satellite receiving antennas currently serving the cable industry are of parabolic design, o Technical Differences in the New and pick up signals from a single Generation Satellites satellite. Since 1983, antenna manufacturers have been improving their designs in anticipation of the 2-degree The technical parameters of next spacing scenario. Cable operators generation C-Band satellites have should find out from antenna improved significantly. Traveling Wave manufacturers which designs need Tube Amplifiers (TWTAs) have modification or replacement. In addition, progressed from 5 Watts to 8 Watts, up proof-of-performance tests should be to its new capability of 16 Watts. The undertaken to ensure that antennas latest in antenna beam-shaping currently meet design specifications after techniques also allow a more uniform many years of use. Corrosion, warping concentration of power to desired and misalignment degrade antenna coverage areas. Furthermore, other performance. spacecraft improvements such as better power subsystem design, better heat management, decreased intermodulation

192-1991 NCTA Technical Papers distortion (IMD), and improved transponder protection schemes Figure 4. shows how the signal ultimately yields a significantly improved quality would change if satellite spacing next generation C-Band satellite system. is reduced to 2-degrees using the next generation satellites. It can be seen that Figure 4. Comparison of Signal Quality larger antennas (4.5M or larger) would be less affected by adjacent satellite interference and therefore would yield signal to noise ratios in the mid to upper Ant. Retiring Next-Gen. fifties (dB) of video signal to noise ratio. Satellites Size Satellites These high values are desirable when 3.0 C/N=11. 4 C/N=14.4 feeding television to cable distribution (M) C/1=23.1 C/1=19.7 systems, even more so as fiber reduces C/N+1=11.1 C/N+1=12.4 its distribution plant degradation and VSN=48.3 VSN=49.6 improves video signal-to-noise in subscriber delivery. 3.7 C/N=13. 2 C/N=16.2 (M) C/1=24.9 C/1=21. 5 C/N+1=12.9 C/N+1=14.2 VSN=50.2 VSN=51.4 o Summary: What is the Impact on 4.5 C/N=14.9 C/N=17.9 Cable Operators? (M) C/1=26.6 C/1=23.2 C/N+1=14.6 C/N+1=15.9 VSN=51.8 VSN=53.1 Satellite and cable operators are 7.0 C/N=18.8 C/N=21.8 now faced with the inevitable challenges (M) C/1=30.5 C/1=27.1 that next generation C-Band cable C/N+1=18.5 C/N+1=19.8 satellites, 2-degree spacing mandate, and VSN=55.7 VSN=57.0 the accompanying movement of cable

Where: programming present. Cable operators C/N = Carrier-to-noise ratio using antennas smaller than 4.5-meters C/1 = Carrier-to-interference ratio or those using multiple beam feeds could C/N +I = Total carrier-to-noise plus interference, calculated as power summations and taking into account be affected. Everyone will experience the slight EIRP differences among adjacent satellites. inconvenience of antenna repainting, so The separation of 3-degrees were used for retiring satellites and 2-degrees for next generation satellites. break out the Liquid Wrench! Some will VSN = Weighted Video Signal-to-Noise Ratio face equipment reconfiguration and perhaps in some cases, replacement. Given: Antenna Efficiency= 65% Antenna Temp=25 oK The transition plan is set, but there is LNA Temp = 70 o K IF Bandwidth= 28 MHz ample time to prepare. The industry EIRP(retiring) = 34 dBW EIRP(next gen) =37dBW needs to work closely with each other to raise awareness of the need to ascertain These improvements are all well the future performance of existing and good, but the forthcoming uniform 2- facilities. Specifically, there is a need to: degree spacing environment will negate 1) Determine the migration plans of the benefits if appropriate steps at the programmers currently carried by the ground segment were not taken. system; 2) determine the impact of 2 o spacing on

1991 NCTA Technical Papers-193 existing facilities; and then, 3) come up with a system-specific technical plan and transition timetable.

By doing so, we will ensure a successful transfer of services to the next generation satellites and maintain the excellent signal quality that we strive to provide to all our subscribers.

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REFERENCES

1. "Reduced domestic Satellite Orbital Spacings at 4/6 GHz," G. Sharp, OST Report FCC/OST R83-2 May, 1983.

2. "Fixed Service: No Surplus in Sight," P. Lambert, Broadcasting Magazine, July 30,1990, pp. 48- 51.

3. Hughes Communications and GE Americom Press releases.

194-1991 NCTA Technical Papers