# PBS Satellite Service

The PBS Satellite Service (also known as the PBS National Program Service, with the primary C-band feed being formerly known as PBS Schedule X in Eastern Time, with the West Coast delay signal designated PBS-XP) consists of feeds relayed from PBS by satellite to public television stations throughout the United States. The service launched on March 1, 1978, with wider adoption beginning in September 1978 as more satellite downlinks were installed at each PBS stations. The service provides a mixed variety of programming selected from PBS's regular network services. In the X/XP years a satellite feed was multicast by some PBS member stations on an over-the-air DTV subchannel along with their regular programming, or during overnight hours on their main channel to provide a second opportunity for viewers to watch or record primetime programming.
PBS currently utilizes one transponder on the Galaxy 16 satellite, transponder 22. This is a MCPC (multiple channel per carrier) which currently has seven channels uplinked from the PBS NOC (Network Operations Center) in Alexandria, Virginia.
Currently, select stations broadcast the feed, usually overnight, like KGTF (PBS Guam, broadcasts most of the channel as a localised feed). The primary feed, known as HD01, is also available over satellite providers like DirecTV (Channel 389), though this feed is down-converted to SD. PBS provides all of their channels free to TV providers who do not receive local member stations.
As of 2023, PBS's satellite feeds, as well as a few other PBS stations, can be received unscrambled using a free-to-air satellite receiver set to these coordinates:
* PBS at 99°W (on the Galaxy 16 satellite), K$_u$-band, unencrypted.
* Montana PBS at 99°W (on the Galaxy 16 satellite), K$_u$-band, unencrypted.
* LPB at 87°W (on the SES-2 satellite), K$_u$-band, unencrypted.
PBS affiliate KETA, part of the Oklahoma Educational Television Authority (OETA), was also available on AMC-21 until June 2016. Their removal from satellite coincided with the completion of their transition to fiber distribution.
PBS transitioned to a fiber-based interconnection system known as sIX, otherwise known as the sixth generation of PBS's interconnection system, in July 2021. The original end date for linear program feeds via satellite was slated for 2016, but was later pushed to 2018, and was then pushed again to the beginning of 2021; none of these deadlines were met. PBS's main network feeds are still active as of June 2023; however, only one NPS feed remains, namely HD03. The only programs airing on this feed are news and public affairs programming; all other linear program feeds have moved to sIX; however, there may occasionally be an unannounced feed of program unrelated to news or public affairs, such as Great Performances.

## History
### 1971–1978: The First-Generation Interconnection System

Starting in 1971, PBS began distributing programs via microwave relay circuits leased from AT&T Long Lines. This was the first generation of PBS’s interconnection system. Prior to this, PBS would distribute programs to stations via "bicycling tapes," meaning that tapes would be shipped between stations through the mail. The interconnection system consisted of nearly 20,000 miles of microwave paths spread across the country. To send programming, PBS would feed these videotaped programs via the AT&T network of microwave relay circuits throughout the country. Instead of each program being received by each individual public television station, these programs were fed to "regional networks," which would then redirect these feeds to stations within their network. Examples of these regional networks included the Southern Educational Communications Association (SECA), which is now known as the National Educational Telecommunications Association (NETA); the Central Educational Network (CEN); the Eastern Educational Television Network (EEN), which is now known as American Public Television (APT); and Midwestern Educational Television (MET). This system made use of a "round-robin" method when distributing programming; this meant that, "a number of stations on the loop can originate to all other stations in the system." The system, however, had its limits. One problem was that video and audio quality would be lessened the farther away a receiving station was due to the distance the program had to travel via the interconnection system. Furthermore, areas outside the contiguous U.S., such as Hawaii, was not "economically feasible," all stations received the same feed, and there was no ability for a second or alternate program feed. In addition, according to PBS, the use of telephone lines to deliver programming was "incapable of producing high-fidelity sound," so they started to look for an alternate method of distributing programming.
PBS began to inquire about the use of satellite for program distribution dating back to 1971. PBS quickly discovered the benefits satellite distribution would have on their operations. A satellite-based interconnection system would allow improved video and audio quality. Unlike the terrestrial-based system, where quality degrades the farther the signal travels, programs fed via satellite would suffer no loss in quality; each station would receive the same copy of the program. A satellite-based system would also allow for more than one program feed.
Before the transition to satellite, PBS utilized what was known as DATE (Digital Audio for TElevision) to transmit stereo audio; however, according to PBS, it was never widely adopted due to "high cost". Decoders for the DATE system cost up to $11,000 in the mid-1980s. PBS recommended that a station purchase at least two decoders, one of these acting as a backup unit. By 1987, "less than half of PBS’s member stations" could adequately decode and broadcast DATE audio signals due to these high costs and the lack of available parts.

### 1978: The Launch of the Second-Generation, Satellite-Based Interconnection System

In 1976, PBS, as well as NPR, received approval from the FCC regarding their plans to create a satellite-based interconnection network. Implementation of this project began in mid-1977.$^{[1]}$ PBS launched their satellite interconnection system on March 1, 1978. This was their second-generation interconnection system. At the time, only 24 stations, all located in the southeastern portion of the U.S., were able to receive the satellite feeds. Throughout 1978, satellite dishes were installed at each public television station in the country. At the end of 1978, all public television stations were now receiving programs via satellite, which ended PBS’s terrestrial-based interconnection system. The interconnection system cost $39.5 million to implement and develop. PBS originally utilized three full-time C-band transponders on the Westar 1 satellite, at orbital position 99°W, to deliver programing, but they also leased a fourth "occasional" transponder beginning sometime in 1980. Westar 2, a satellite at orbital position 123.5°W, would be designated as a backup in case of a failure of Westar 1. In 1982, Westar 4 replaced Westar 1 in the same orbital position; PBS transferred their feeds to this new satellite. One primary advantage of Westar 4 was that it contained 24 transponders, compared to Westar 1’s 12 transponders.
To communicate with stations, PBS launched a service called the Dial Access Communications System (DACS). DACS, considered a form of "electronic mail," allowed PBS and its stations to communicate with each other about private matters. On July 21, 1995, a new communications system, known as PBS Express, launched. PBS Express launched alongside DACS, which would be discontinued in 1996. Stations now communicate private matters via myPBS, launched in 2013, which is where stations are alerted to new program offers from PBS and other distributors, any schedule changes, or program availability changes. Other station matters are also communicated via The Hub.

### 1987: Controversy Surrounding Potential Use of VideoCipher II

During this time, PBS did not utilize any type of encryption on their feeds. However, beginning in mid-1987, PBS began to explore the possibility of encoding their feeds with VideoCipher II. With PBS planning to encode their feeds with VideoCipher II, home-dish viewers of PBS’s feeds began to voice concerns that PBS was preparing to encrypt their feeds. One of these viewers was named Diane Friedel Davis, who lived in St. Joe, Arkansas, a rural part of the state; she appeared before a congressional hearing on July 31, 1987, to discuss the recently proposed Satellite TV Fair Marketing Act. This act, as it relates to public broadcasting, stipulated, "No person shall encrypt or continue to encrypt satellite delivered Public Broadcasting Service programming intended for public viewing by retransmission by public broadcast stations." PBS had "serious reservations" about this and requested that this section be removed from the proposal. Michael E. Hobbs, the former Vice President of Policy and Planning for PBS, urged congress to remove this section. "We urge you to delete the section that prohibits PBS from scrambling: not because we want to scramble, but because the practical effect of that section would be to freeze public television in the backwater of an obsolescent technology, and deny real benefits to home dish owners and broadcast viewers alike," he said in a statement. In Diane’s statement, she echoed the sentiment felt by home-dish viewers at the time by expressing her worry about PBS potentially encrypting their signals. "PBS… [does] not have a right to scramble our public airwaves," she said in her statement. In a written statement, she said that using a satellite dish was the only way for her to receive television broadcasts because not only would a television antenna not receive a signal, but the local cable company was not willing to travel such a long distance to establish service. "If a satellite dish is the only way a person can receive that signal, then he/she should be allowed access," she said in her written statement. She continued, "There are the farmers, the elderly, the physically challenged, and millions of rural Americans who, for one reason or another, live in remote and isolated areas of this vast country. For them, television is their window. Should these people be denied their First Amendment rights just because they do not live in urban or suburban areas where a television signal is received over a standard VHF antenna?"
According to PBS during the July 1987 hearing, VideoCipher II would not be used for general encryption purposes, but rather more efficient stereo audio and the opportunity to add other audio services, such as Descriptive Video Service or a Secondary Audio Program. David Hobbs later explained more concerning the reasoning for using VideoCipher II. "We are planning to use that technology to install stereo audio capability system-wide, a dream that we have had in public television for 20 years. We are also working on the development of Descriptive Video Services for the blind, and multi-lingual audio tracks for the non-English-speakers in our audience." Utilizing VideoCipher II would also be cheaper for PBS and its stations; VideoCipher II decoders cost an average of $500 and could be easily found on the market. He also made clear that PBS’s proposal to use VideoCipher II did not mean eventual encryption. "We at PBS are proud to have worked vigorously since our earliest days to extend public television service to as many Americans as possible. …In keeping with that commitment, PBS has never scrambled any satellite transmission of our program service. We have not done so, and we have no plan to do so." In a later statement, he reaffirmed this point again by saying, "At the outset, I would like to say once again that PBS has no plans to encrypt its regular program transmissions." In April 1988, PBS began encoding programs with VideoCipher II. The feeds were usually broadcast in a "fixed key" mode (usually 0000), which allowed anyone with a VideoCipher II receiver to be able to receive these feeds. PBS, however, would encrypt the feeds anytime they aired what they referred to as "private communications," which include teleconferences and previews of programs that they haven't yet received broadcast rights for; all other programs remained unencrypted.
The use of VideoCipher II also created confusion among home-dish users who did not have a way to view content encoded with VideoCipher II since, "they have not been able to get reliable information as to the schedule for PBS's 'clear feeds.'" To combat this, PBS took several steps to accommodate these viewers: publishing schedules in satellite magazines, broadcasting nearly every "clear" program transmission on one transponder, broadcasting a slate showing a program schedule, creating an office to answer viewer questions, broadcasting an audio barker message to explain how to obtain a schedule, and sending viewers a monthly schedule of programs upon request.

### 1991–1997: The Third-Generation Interconnection System

In 1987, PBS, along with the Corporation for Public Broadcasting (CPB), approached Congress with a request upgrade the interconnection system. On March 15, 1988, Bruce L. Christensen, the President of PBS at the time, appeared before a Senate committee to discuss the proposed Public Telecommunications Act of 1988. "The satellite currently used by public television (Westar 4) will run out of fuel by mid-1991, which means that public television must find new satellite capacity," he said in a statement. "Faced with a failing satellite and deteriorating ground facilities, public television must acquire a new satellite distribution system if it is to continue its present services, let alone provide new opportunities for all Americans, in the future." The proposal, "authorizes an additional $200 million to be used over a three year period to replace the satellite interconnection system."
The Public Telecommunications Act of 1988 became law on November 7, 1988, guarantee funding for the upgrade of PBS’s interconnection system. This act included a provision stating that PBS must provide a "clear" feed of its programming to home-dish viewers who do not have a decoder. This act also created a committee to research and propose new plans regarding replacement of the satellite used for the interconnection system, known as the Public Television Interconnection Committee. The committee was made up of "designated representatives of the public stations". This committee approved a satellite replacement plan in December 1981, with PBS's board endorsing the plan. In this plan, PBS would continue to lease four C-band transponders starting in 1991, with the goal being to convert their satellite operations to Ku-band sometime in 1993 or 1994. In 1991, PBS purchased C-band transponder space on the Spacenet 1 satellite, owned by GTE, at orbital position 120°W. This move occurred on January 3, 1991. This began the third generation of PBS’s interconnection system. The system was guaranteed to last at least 15 years, until 2006. PBS later moved their feeds to a new satellite, Spacenet 4, at orbital position 101°W, on July 18, 1992.
The move to Spacenet 1 and, later, Spacenet 4 was only a temporary solution. In 1989, an agreement was reached with AT&T for PBS to purchase transponder space on a new satellite named Telstar 401, which wouldn’t launch until 1993. Six Ku-band transponders were purchased, but one C-band transponder was purchased; this C-band transponder was purchased to fulfill the "clear feed" requirement in the Public Telecommunication Act of 1988. This C-band feed was the "PBS-X" service. PBS’s primary reason for converting to a Ku-band system was to take advantage of "more advanced technical capabilities available on Ku-band transponders," such as increased transponder bandwidth and an increase in the number of services that could be provided. PBS also wanted to create an “educational neighborhood” on Telstar 401 where other public educational services, including PBS’s services, would be on the same satellite. PBS said that as many as 80 educational services would be provided via Telstar 401, allowing libraries, schools, and universities to access a multitude of programming on the same satellite. Telstar 401 launched on December 16, 1993. PBS moved to Telstar 401, at orbital position 97°W, on February 5, 1994, ending primary program distribution to affiliates via C-band. Telstar 402R, a satellite that launched to orbital position 89°W on September 24, 1995, would serve as a backup.
In 1994, with the launch of the Ku-Band feeds, PBS began testing DigiCipher I, the digital equivalent to VideoCipher. Initial tests proved to be successful, leading PBS to adopt DigiCipher I for all their services in August 1994. PBS had wanted to use the newest version of DigiCipher, known as DigiCipher II, but due to "delays in the adoption of MPEG-2," PBS said that they wouldn’t be able to utilize DigiCipher II until "late 1995". Sometime in early 1996, PBS made the switch to DigiCipher II and, in the process, converted their services from analog to digital.
On January 11, 1997, at 6:15 a.m., Telstar 401 suffered a failure due to a coronal mass ejection. AT&T tried to re-establish contact with the satellite, but all attempts failed. To restore service, PBS temporarily moved their feeds to Telstar 402R (later Telstar 4). To prevent noticeable interruption to their service, PBS carried out a Satellite Service Recovery Plan. It took “less than 25 minutes” for PBS to switch service to Telstar 402R, preventing a severe disruption to their services.

### 1997–2006: The Fourth-Generation Interconnection System

The fourth generation of the interconnection system launched in 1997. In April, an agreement was made with GE Americom for PBS to purchase transponder space on GE-3, a satellite at orbital position 87W that launched on August 9, 1996. PBS moved to GE-3 in October 1997. The use of this satellite caused some trouble for areas outside too contiguous U.S., such as Alaska and the Caribbean islands, because these areas were outside the satellite’s footprint. To remedy this, PBS purchase one C-band transponder on another GE satellite, GE-1, which was at orbital position 131°W. There were not many major changes between the third and fourth generation interconnection systems.

### 2006–2018: The Fifth-Generation Interconnection System

In 2004, PBS published a proposal for the fifth generation of their interconnection system, known as the Next Generation Interconnection System (NGIS). PBS and the CPB expected the upgrade to cost $177 million. PBS had three reasons for upgrading the interconnection system, one of these being that their satellite contracts were scheduled to end on October 4, 2006. The current fourth generation interconnection system would be 15 years old in 2006; PBS said that this system "has run its course" and needed to be upgraded. Adding on to this, PBS wanted a new system that could fully support digital television. One other reason for the upgrade involved "[leveraging] new technologies to enhance efficiency and service to stations." PBS warned that the NGIS must be operational by October 4, 2006, otherwise, "PTV will be unable to function in its current form." One important aspect of the NGIS was that it would allow PBS to distribute programs in non-real time (NRT) by sending programs as digital video files to public television station by using a terrestrial Internet-based network. PBS said that the "vast majority" of programming would be sent via NRT distribution, a move away from the tape-based interconnection system currently in use. Files would be stored on "cache servers" at each public television station. Even with NRT program distribution, PBS was still committed to satellite distribution, but mainly reserved satellite distribution for live or near-live programs with a "short turnaround," such as A Capitol Fourth, Charlie Rose, and The NewsHour with Jim Lehrer; other programs besides these, such as children’s programming and other general prerecorded programs, would still be fed via satellite. The NGIS would also revolve heavily revolve around the Internet, allowing public television stations and PBS to contact each other more easily.
PBS stated within their report that the NGIS would lead to "increased efficiency" of the distribution or programs. According to PBS, "smaller, financially strained, rural market" stations would air a program as it was being fed via satellite; this was done to save costs. This method led to many "redundant national program feeds," with PBS saying that one program would be fed "as many as five times or more" in a single day. Some of these refeeds would also occur due to weather interfering with satellite reception or due to problems recording the program to tape. In 2001, PBS distributed nearly 120,000 hours of programming through their interconnection system; according to PBS, "all but 7,000 hours were repeated programming" feeds. By using NRT distribution, these redundant feeds would be greatly reduced. The NGIS would also save be cheaper to operate, with station expected to save between $50,000 and $250,000 ever year. PBS expected this system to last about 10 years. The NGIS would launch in October 2006. When the new system launched, PBS launched a transponder that would carry IP data via satellite on two services called NR01 and NR02; these would be the services used for NRT program distribution. NR01 would feed national PBS programs and NR02 would sometimes feed programs from other distributors, such as NETA. Programs would be sent as MXF files. PBS also made the switch to DVB-S MPEG-2 when the new system was launched.
During planning for the NGIS, PBS considered seven different models for this interconnection system.
* The first model would’ve continued the current operations of the fourth generation interconnection system, with all programming being fed via satellite. The number of transponders would decrease from seven to six. PBS eliminated this model from consideration because they claimed that this was no longer an adequate option due to advancements in digital television; NRT distribution was also not possible.
* The second model was like the first model but would make use of a local "cache server" at the public television station. This model would have considerably decreased the number of transponders, going from seven to three. This model was eliminated for the same reasons as the first model.
* The third model incorporated both satellite and terrestrial distribution, in addition to "terrestrial transaction management". PBS selected this model due to its "reasonable cost and low risk".
* The fourth model would’ve reserved satellite distribution solely for real-time programming and terrestrial distribution solely for non-real time programming. This model was eliminated due to "high operational and implementation costs," with PBS saying the cost of this model would have been "double" that of the model selected for the NGIS.
* The fifth model was like the first model, an all-satellite distribution system, but would’ve incorporated both Ku-band and Ka-band satellite. PBS said that there was "significant risk" with this model because, at the time, Ka-band technology was "untested," meaning they had no "proven business model" of a Ka-band system operating without trouble. At that time, Ka-band satellites for commercial use did not exist, not to mention that investment costs that covered the satellite’s lifespan could total up to $2 billion. PBS also didn’t think "any satellite communications company will base their operation on public broadcasting's business".
* The sixth model would’ve created a terrestrial interconnection system that would’ve distributed all programs, both real-time and NRT. Satellite would continue to be used for "a small percentage of live and near-live programs," but terrestrial distribution would be the primary method of distribution. This model was eliminated due to "extremely high capital and operating costs," with this model expected to cost nearly three times the operating price of the current NGIS model. PBS noted that terrestrial distribution at this scale wasn’t yet possible, but said, "In the future, this model may provide significant opportunities."
* The seventh model, the last to be considered, would use satellite to distribute live and near-live programs, but all other programs would be distributed to stations via "fixed media," such as DVDs. This method has similarities to the "bicycling tapes" system used by PBS before 1971 in that stations would receive a physical copy of programs, being DVDs in this case, through the mail, but these DVDs would not be sent to other stations after one station was finished broadcasting the program. This model was eliminated because it would have created "significant operational complexity" for the public television stations, in addition to there being an "extremely high operational cost and complexity and high risk."
In 2008, PBS switched to a new satellite, AMC-21, which would be in orbital position 125W. In October 2012, PBS began encoding their feeds in the DVB-S2 MPEG-4 codec, which they currently use.

### 2018–present: The Sixth-Generation Interconnection System

In June 2015, the CPB began to consider options for the sixth generation of PBS’s interconnection system, known at the time as "v6". To help consider their options, they commissioned the help of Cognizant Technology Solutions to come up with a new cost-effective solution to improve the Public Television Interconnection System. A report discussing the proposed model for the sixth generation of the interconnection system was published in November 2015. Included in this report were the results of interviews with twelve public television stations, who were chosen as a representative sample of all public television stations; these stations were asked about their satisfaction with the fifth generation interconnection system, the NGIS (referenced in the report, and hereafter, as "v5"). Two-thirds of interviewed stations, eight out the chosen twelve, expressed dissatisfaction with the current version of the interconnection system. Overall, according to these stations, the v5 system was able to "effectively" distribute live and near-live content, but as for NRT content, this was where the v5 system failed. NRT program feeds were not "reliable" nor were they "consistent," and because of this, there were "many" stations, according to the report, that did not "fully adopted v5"; two stations that were interviewed "did not use the v5 system at all". Indeed, the delivery of NRT content was the biggest problem with the v5 system, with 90% of stations (based on the representative sample size described earlier) agreeing that receiving NRT content was problematic.
With that, Cognizant's recommendation was "that the system adopt a single interconnection system that is cloud-based, using mainly the public internet and an ecosystem of centralized master control service providers". The selected model would primarily utilize "a terrestrial fiber-based network," with satellite being used as a back-up. This system would decrease the number of transponders used by PBS from three to one. As part of this plan, PBS would switch their primary feeds back to the C-band spectrum beginning in March 2016; however, this transition never occurred. The primary plan was to transition linear program feeds via satellite, as well as programs fed via the NRT transponder, to the terrestrial-based system. One of the key benefits of the v6 system was that it would allow stations to send content to each other via FTP (File Transfer Protocol), allowing for P2P (peer-to-peer) sharing. By using an FTP client, all stations could easily send content to each other. However, stations could still receive physical media, such as tapes (usually HDCAM) and disks (usually XDCAM discs) “via courier service”. These formats were usually bicycling formats. The v6 system also allowed for cloud-based storage of content instead of local storage, which allowed for a more efficient approach to storing and managing content, as well as the possibility for a "joint master control" operations. CPB expected this system to be completed and operational by May 2018. The CPB tasked Vigor Systems, Inc. with developing and deploying the new interconnection system. According to Vigor, this interconnection system is known as sIX ("six"), the official meaning being "Service Interconnection."
PBS, its affiliates, and its partners upload content to a central cloud-based hub that allows stations to download content that will be broadcast. sIX is based on OneVigor's PitchBlue distribution platform, which is used by networks such as CBS. To manage content, stations make use of either the Myers ProTrack or OneVigor platforms. Downloaded programs are then saved to online servers known as Edisen Edge servers (formerly known as MagnuBoxes). Uploads of programming to sIX occur at different times; for example, a new episode of a program may be uploaded to sIX approximately 12 hours before the program feeds on HD01. Other times, uploads may be scheduled for specific dates and times. There are times when an entire season of a program becomes available at once and other times where episodes of programming are uploaded weekly. Some programs, such as premieres of new episodes of Amampour and Company, Democracy Now!, and Frontline, in addition to live events, are not initially available via sIX as downloadable files; they are only available through the linear satellite or terrestrial feeds of HD01 and HD02 (for Amampour and Company and Frontline) or linear terrestrial feeds of HD64 and HD65 (for Democracy Now!, BBC News programs, and NHK programs). However, episodes of these programs will later be uploaded to sIX after the initial satellite or terrestrial feed. Programs also have an expiration date; once this date arrives, the file is removed from the sIX platform and can no longer be downloaded. Program files are always delivered in the MXF OP1a container (regardless if a program is in HD or UHD) with most HD programs encoded in the XDCAM HD422 codec (MPEG-2 Long GOP @ 50Mbps), which is the preferred delivery format for PBS. Other codecs that are approved for use when delivering in HD are three versions of the DNxHD codec: DNx145, DNx220, and DNx220x. For UHD content, PBS has approved three versions of the DNxHR codec: DNxHR HQ, DNxHR HQX, and DNxHR 444.

#### Transition away from satellite

Testing of sIX commenced in March 2018. With initial tests proving successful, PBS discontinued their NRT (non-real-time) file-based services on AMC-21, NR01 and NR02, created as part of the NGIS interconnection system, sometime in Q4 2018. The goal was to move all linear-fed content to sIX in the near future. The rollout of sIX is occurring in several phases. Phase 1 involved phasing out the NRT file-based Ku-band transponder. Phase 2 began in 2020 and is currently ongoing, which according to a May 2021 report from the CPB, "considers future options for the delivery of linear and live content." The report says that later stages will be "defined as business and technology needs evolve." PBS has expressed that they will continue to lease transponder space for live and near-live programs, such as the PBS NewsHour; PBS will also continue to lease transponder space in the event their sIX system suddenly fails or experiences an outage. According to KNME (New Mexico PBS), "99% of Public Television Stations have successfully implemented sIX functionality".
As the transition to sIX has progressed, PBS began to shut down some of their NPS satellite distribution feeds. The first feed to shut down was PBS's SD01 service, shutting down on September 5, 2016. Two years later, as previously mentioned, the NRT file-based service was shut down sometime near the end of 2018. On March 4, 2019, PBS's C-Band feed on SES-3 (103°W) was discontinued, leaving PBS with no active C-band transponders for the first time. On November 13, 2019, PBS discontinued their SD07 Ku-band service on AMC-21, which was uplinked from SCETV in Columbia, South Carolina.
The transition to sIX accelerated in March 2021 when APT began to transition select programs off satellite and into the sIX system. In July 2021, programming from the NETA and APT migrated fully to sIX, ending distribution via satellite. However, three programs from APT – Consuelo Mack Wealthtrack, GZERO World with Ian Bremmer, and Laura Flanders & Friends – continue to be fed via satellite on HD03 on Fridays, with sIX uploads of each episode occurring after the satellite feed. Program uplinks from KNME, with the exception of Democracy Now! until the closure of the HD05 service on May 31, 2023, also migrated to sIX. PBS themselves had also migrated many regular, non-news linear feeds to sIX, including feeds of pledge programs, which were last fed in May 2021. The only content left on their three (at the time) primary NPS HD distribution feeds, HD03, HD04, and HD05, was news and public affairs programming. On July 21, 2021, a few weeks after this transition, PBS decommissioned two more satellite feeds, SD05 and SD06, at 2:56 p.m. ET.
On January 20, 2023, PBS's main transponder on AMC-21 (which included HD01-HD03, HD06, SD02, SD04, and SD08) began simulcasting on Galaxy 16, a satellite at orbital position 99°W. On May 3, 2023, a ticker appeared on HD04 and HD05 alerting that both services would shut down on June 1, 2023, at 00:00 UTC (May 31, 2023, 8:00 p.m. ET); the ticker was later updated on May 25, 2023, with a new shutoff date of May 31, 2023, at 23:59:59 p.m. ET (11:59:59 p.m. ET). In the ticker, PBS said that program feeds on HD04 and HD05 would move to two new terrestrial-based services, HD64 and HD65; this was part of one of the phases of the sIX transition, which involved transitioning feeds from HD04 and HD05 to these new services. On May 31, 2023, at 11:58:52 p.m. ET, PBS completed the move to Galaxy 16. HD04 and HD05 were decommissioned at the same time.
In 2024, PBS started testing new terrestrial feeds as part of their sIX interconnection system. These services are the same as the current satellite feeds on Galaxy 16 (HD01, HD02, HD03, HD06, Create, and World). A terrestrial feed of HD03 launched on the sIX platform in December 2024. FNX will be added at a later date. This is part of a new phase on the sIX rollout known as Phase F2, which is currently ongoing. It is not known whether PBS will decommission the satellite feeds once Phase F2 is complete. For now, stations record programs from both the satellite and terrestrial feeds, with one or the other acting as a backup.

## Channels

The channels currently available via Ku-band satellite on Galaxy 16 at 99°W are listed below (Lyngsat).
* Montana PBS (this transponder is independent of PBS's other feeds)
* HD01 (PBS East)
* HD02 (PBS West)
* HD03 (NPS Feed)
* HD06 (PBS Kids Channel)
* SD02 (Create (TV network))
* SD04 (World (TV network))
* SD08 (FNX)
Discontinued Feeds:
* HD04 (NPS Feed, SCPC) (December 10, 2008 - May 31, 2023)
* HD05 (NPS Feed, SCPC) (June 2013 - May 31, 2023)
* SD01 (NPS Feed) (December 9, 2008 - September 5, 2016)
* SD03 (V-me) (December 9, 2008 - March 2017)
* SD05 (NPS Feed, SCPC) (December 10, 2008 - July 21, 2021)
* SD06 (NPS Feed, SCPC) (December 10, 2008 - July 21, 2021)
* SD07 (NPS Feed, SCPC) (December 10, 2008 - November 13, 2019)
* 1 2 3 4 5 6 7 8 9 In Standard-Definition.
* 1 2 3 4 5 6 In High-Definition.

## Overview of Past Services

Throughout much of their history on satellite, PBS utilized four transponders corresponding to a different "Schedule," namely 'Schedule A,' 'Schedule B,' 'Schedule C,' and 'Schedule D'. Another feed, Schedule E, launched in 1988. Also starting around 1988, PBS would begin displaying an on-screen schedule on their feeds; this was in response to confusion and concerns from home dish users concerning schedule availability. PBS did previously display a schedule of upcoming program feeds on their services, but instead of listing program names, they used NOLA codes, a broadcast code that PBS assigns to every program they broadcast (e.g. "GPER" for Great Performances). PBS would later drop this practice starting around 1996. On August 15, 1994, to coincide with an ongoing transition to digital, PBS launched nine new services to replace the former A, B, C, D, and E feeds, namely: 5A0, 5A5, 5B0, 5B5, 5B6, 6, 7L, 7U, and 8. Some of these services, such as Schedule 5A0 and 5A5, shared the same MCPC transponder. PBS utilized four transponders on Telstar 401 during this time, transponders 5-8. Transponder 5 was a digital transponder and was reserved for PBS full-time. Transponders 6-8 were analog and were shared transponders, meaning other educational services would utilize the transponders for a period during the day; however, PBS had full control over these transponders during weekends. In 1997, PBS would rename their services with the prefix "50-" (Schedule 501, 502, etc.). There were five primary NPS feeds, Schedules 501–505, in addition to three SCPC feeds, Schedules 511–513. Schedule 511 was the primary feed for APT content, in addition to other SD content; this service originated from CPTV in Hartford, CT, most of the time. Schedule 512 was reserved for regional uplinks and other SD content. Schedule 513 was the primary feed for NETA content and other SD content; this service originated from SC ETV in Columbia, SC, for most of the time. Schedule 505, based on available information, was decommissioned by PBS sometime in 2007. Full-time services were Schedules 500 (PBS-X), 540 (PBS-X) and 543 (unknown service as of December 2024). In the early 2000s, PBS launched 5 new services that would exist alongside the current SD feeds: DT1A, DT1B, DT1C, DT2A, and DT3A. The DT2A service launched on March 1, 2004. DT2A was the national feed for the then-new PBS HD channel. At the beginning of 2008, PBS the DT3A service. DT3A was the primary HD soft feed channel that was used to feed HD content to stations, such as HD broadcasts of the PBS NewsHour (then known as The NewsHour with Jim Lehrer). As for the DT1A, DT1B, and DT1C services, there is no other available information about these services as of December 2024.
During its operation, the PBS Adult Learning Service (ALS) fed programming via satellite, offering college telecourses and other adult education programs. When the service launched on August 29, 1981, feeds occurred on Schedule A during weekends. During weekdays from 9:00 a.m. to 5:00 a.m. ET, ALS feeds were on Schedule D. During the digital transition in August 1994, ALS feeds moved to Schedule 7U. The feed times remained unchanged. With the launch of Schedule 503 in 1997, ALS feeds moved to this service. The ALS was most active during academic semesters, mainly during the Fall semester (August–December) and Spring semester (January–May), though there would be occasional “blockfeeds” (multiple episodes of one program, usually more than two episodes, fed in a row) during the months of June and July. In addition to PBS programs produced for the ALS, programs from Annenberg/CPB were also fed on this service. The ALS was discontinued in September 2005.
In December 2008, with the transition to HD, PBS launched new services that would phase out and consolidate some of their existing SD services. SD01-SD04 launched on December 9, 2008; HD04 and SD05-SD07 launched on December 10, 2008; and HD01-HD03 launched on December 21, 2008; all launching at 6:00 a.m Eastern. Programming on HD04 began on December 21, 2008. Programming on SD01 began on February 11, 2009. SD01, SD03, SD05, SD06, and SD07 are now defunct. DT2A and DT3A were discontinued on December 21, 2008, at 6:00 a.m, HD01 and HD02 replacing both services. Schedules 500 (PBS-X), 501–504, and 540 (PBS-XP) were discontinued on February 11, 2009.
SD01 was a new “soft feed” service and would serve as the main service to distribute PBS content produced in SD. Teleconferences and other SD content from other distributors would be on this service. A few services were renamed during this transition. Service 515, Create, was renamed SD02; Service 505, V-me, was renamed SD03; Service 506, World, was renamed SD04. In addition, SD05 would replace Schedule 511, SD06 would replace Schedule 512, and SD07 would replace Schedule 513. HD01 would become the main HD feed of PBS programming, becoming the PBS East feed. This service incorporated feeds from Schedule 500 (PBS-X), Schedule 501, Schedule 502, and DT2A (the former PBS HD Channel). PBS-X feeds that moved to HD01 included the weekend schedule of programs and “late night NPS repeats”. Feeds of kids programming during the weekday on Schedule 501 and primetime “ETZ” (Eastern Time Zone) feeds from Schedule 502 also moved to HD01. HD02 would be a three-hour delay of HD01, serving as the PBS West feed. Like HD01, primetime feeds from Schedule 502 would move here, but only the “PTZ” (Pacific Time Zone) feeds. HD02 was the replacement for DT3A; soft feeds on DT3A would move to HD03. Schedule 540 feeds (PBS-XP) moved to HD02. HD03 would become the main service used by PBS to distribute HD content to stations. This service would carry content such as soft feeds, promo reels (from PBS and APT), pledge feeds, preview feeds, and other distributor content, such as content from APT.
HD04 would be the first HD SCPC feed. This service would have minimal content from PBS and would instead distribute content from other distributors, such as NETA, or other regional uplinks. This feed was the primary feed for NETA programming until July 2021, when all NETA programs moved to sIX. This feed was used solely for affiliate uplinks, with the exception of a few programs on HD05, usually from KNME. APT utilized this service to sometimes feed HD promo reels as well. Daily feeds on HD04 included four feeds of BBC News programming (two feeds of BBC World News, BBC World News Outside Source, and BBC World News America, with BBC World News Today airing weekly on Fridays), and six feeds of NHK Newsline originating from Connecticut Public Television. This feed shut down on May 31, 2023. The final feed was an 11:00 p.m ET airing of BBC News.
In June 2013, PBS launched their HD05 feed. HD05, like HD04, was occasionally uplinked from various sites as well as the PBS NOC. Pledge feeds were likely to be uplinked on this feed as well during pledge seasons until February 2021, when nearly all pledge feeds moved to HD03. Daily feeds on HD05 included two feeds of Democracy Now! (originating from KNME) and two feeds from DW (DW News and The Day). Weekly feeds included a feed of DW's Euromaxx on Tuesdays and a feed of White House Chronicle on Fridays. Other weekly feeds included a feed of Florida Crossroads on Monday and Capitol Update on Fridays and Saturdays (originating from WFSU), as well as two back-to-back feeds of Market to Market (originating from Iowa PBS). HD05 did serve as the feed reserved for live political events covered by the PBS NewsHour. These broadcasts were originally fed on SD05 until the feed was shut down on July 21, 2021. This feed shut down on May 31, 2023. The final feed was a 4:30 p.m ET airing of DW's The Day.
The newest feed to be launched by PBS was their HD06 feed in October 2016, initially airing only a test pattern. This feed was reserved for the new iteration of the PBS Kids channel, which launched in January 2017.

## Current services

The PBS Satellite Service is freely and nationally available from the designated Ku-band broadcast satellites using free-to-air satellite dishes as small as 30 inches. Before PBS's transition to their new interconnection system in July 2021, the three (at the time) 'Schedule' feeds (HD03, HD04, HD05) used to broadcast different programs at various times throughout the day, with weekends and late night hours usually having no feeds. Some program feeds were only temporary and were usually not consistent. PBS would usually feed programs a few days to as long as a few weeks in advance. The former SD05 and SD06 services were rarely utilized, usually showing a test pattern for the whole day, though SD05 would occasionally show live feeds of major political events, such as confirmation hearings for new Supreme Court justices and, more recently, the entirety of the first and second impeachment trials of former President Donald Trump. SD05 (and sometimes SD06) was also used for host teleconferences from APT.
When no program is being fed, the channels would broadcast a slate displaying the name (e.g. Schedule HD03) and the time & date (both Eastern and Pacific time are shown).
HD03 is uplinked from the PBS NOC 24/7 and was the sole service for pre-feeding PBS programs before the transition to sIX. This service was also the primary service for a majority of programs from APT until July 2021, when all APT programs (except the three mentioned previously) moved to sIX. This service mostly fed soft feeds, pre-feeds, and until January 2020, promo reels (which have moved to PBS Source, which is where promos and other promotional material are hosted). Daily feeds on HD03 include East and West feeds of PBS NewsHour (including two feeds of PBS NewsHour Weekend during the weekend) and one feed of Amanpour & Company every weekday. MotorWeek, To the Contrary with Bonnie Erbé, and White House Chronicle continue to be fed on Fridays. The service is also used to feed repackaged versions (usually versions with synchronized captions and "Previously Recorded" logos) of live programs such as A Capitol Fourth, the National Memorial Day Concert, and live episodes of Great Performances.

## Various videos of the service

* https://www.youtube.com/watch?v=phF2IsbBt84 (Schedule B, May 10, 1990; electronic programming guide showing a schedule for part of the current day's programs)
* https://www.youtube.com/watch?v=-S80WKV67sY (Schedule B, March 17, 1992; EPG showing the day's programs)
* https://www.youtube.com/watch?v=gTvdHsI3VzY (PBS-X, 1994; PBS ident with a schedule of programs and a looped text message reading, "On this transponder, you'll find programs from the PBS National Program Service and programs from other Public TV distributors as well.")
* https://www.youtube.com/watch?v=Y0peKirF1SI (PBS-X, 1995; 5-second ident saying, "You're watching PBS. Viewer supported public television.")
* https://www.youtube.com/watch?v=9K6YiPSEsvU (2001; During 9/11 The NewsHour With Jim Lehrer credits before PBS Kids)
* https://www.youtube.com/watch?v=MwiCfrngm-Q (HD01, 2018; PBS Promos before Mister Rogers' Neighborhood)
* https://www.youtube.com/watch?v=gE1mmx8US8A (Schedule SD01, July 1, 2016)
* https://www.youtube.com/watch?v=ps9w_Q8POfo (Schedule HD03, July 6, 2016; Test Pattern and slate before Charlie Rose; this is the current layout.)
* https://www.youtube.com/watch?v=7bdGQL4FPj4 (Schedule HD04, June 16, 2021; Test pattern and slate before BBC World News America.)
* https://www.youtube.com/watch?v=JdhbQeb8L0A (Schedule HD05, August 31, 2020; Test pattern and slate before a pledge program, titled Ken Burns: The Civil War.)
* https://www.youtube.com/watch?v=TO7saQEQDTE (HD04/HD05 shutdown notice with a scrolling ticker at the bottom, May 3, 2023.)