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Wireless Communications Service (WCS)
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The following discussion on WCS is from FCC 10-82 (May 20, 2010):
The Commission's rules define WCS as a radiocommunication service licensed pursuant to Part 27 of the Commission’s rules in specified frequency bands, including the 2305-2320 and 2345-2360 MHz bands. The Commission established the WCS in February 1997.27 Licensees in this service are permitted to provide fixed, mobile, portable, and radiolocation services. The Commission found that allowing a broad range of services would permit the development and deployment of new telecommunications services and products to consumers. Specific potential services advocated by WCS proponents in 1997 included high-speed wireless Internet access, return links for interactive cable and broadcasting services, mobile data, fixed terrestrial use, and the provision of wireless local loop services. The Commission auctioned 128 WCS licenses in April 1997. In July 1997, the Commission issued licenses to the WCS auction winners.
WCS Blocks A and B
In 1997, the Commission awarded WCS licenses for 2 paired 5-megahertz-wide channel blocks (WCS Blocks A and B) in 52 Major Economic Areas (MEAs) authorizing service on 10 megahertz of spectrum. WCS Block A is comprised of spectrum at 2305-2310 MHz paired with 2350-2355 MHz. The lower band edge of Block A (2305 MHz) is adjacent to a 5-megahertz-wide Amateur Radio Service band at 2300-2305 MHz, and second adjacent to Federal Deep Space Network (DSN) Receivers at 2290-2300 MHz. WCS Block B is immediately above Block A, and is comprised of spectrum at 2310-2315 MHz paired with 2355-2360 MHz. The upper band edge of Block B (2360 MHz) is adjacent to an Aeronautical Mobile Telemetry (AMT) Service band at 2360-2395 MHz.
WCS Blocks C and D
The Commission also awarded WCS licenses for 2 unpaired 5-megahertz-wide channel blocks (WCS Blocks C and D) in 12 Regional Economic Area Groupings (REAGs) separately authorizing service on 5 megahertz of spectrum. WCS Block C is located at 2315-2320 MHz and is adjacent to the lower band edge of the SDARS spectrum at 2320-2345 MHz. WCS Block D is located at 2345-2350 MHz and is adjacent to the upper band edge of the SDARS spectrum.
Although the Commission permitted WCS licensees to provide both fixed and mobile services, it adopted different power and OOBE limits for these two classes of service. For WCS fixed operations in the 2305-2320 and 2345-2360 MHz bands, the Commission adopted a power limit of 2 kW peak EIRP. The Commission also required WCS fixed stations' OOBE to be attenuated below the transmitter power (P) within the SDARS frequencies of 2320-2345 MHz by a factor not less than 80 + 10 log (P) dB. For WCS mobile stations, the Commission adopted a peak power limit of 20-W EIRP and required an OOBE attenuation factor of not less than 110 + 10 log (P) dB within the SDARS frequencies. The Commission adopted these power and OOBE limits, in part, to protect neighboring SDARS operations from harmful interference.
Originally, the Commission's rules required WCS licensees to make a showing of substantial service in their license areas by the end of their initial 10-year license term, which commenced on July 21, 1997. However, in December 2006, the Wireless Telecommunications Bureau (WTB) granted a 3-year extension of the construction deadline for certain WCS licensees. WCS licensees argued, among other things, that the uncertainty regarding the rules governing the operation of adjacent-band SDARS terrestrial repeaters had hindered WCS equipment development, network design, and facility deployment, and that an extension would allow them to deploy newly developed WiMAX technology in the 2.3 GHz band in the next few years. WTB found that the possibility of WiMAX deployment warranted a 3-year extension of the initial 10-year construction requirement. Thus, the current deadline for meeting the construction requirements set forth in Section 27.14 of the Commission's rules was extended until July 2010 for WCS licensees.
Historical Information on WCS
The following historical information on WCS is from Wireless Spectrum Finder, by Benn Kobb, last published in 2001. Wireless Spectrum Finder is now (c) SpectrumWiki.com.
*****
With a fund-raising mandate from Congress that identified specific bands for auction, the FCC allocated 2305—2320 MHz and 2345—2360 MHz to a flexible new service.
It received the generic placeholder name Wireless Communications Service (WCS) after an internal FCC naming contest failed to attract any non-frivolous entries. The FCC later added 700 MHz spectrum to WCS and renamed it the Miscellaneous Wireless Communications Services (see 746—764 MHz), although the service is still generally called WCS.
The FCC also proposed to add frequencies in the 4.9 GHz band to WCS: spectrum formerly intended for the General Wireless Communications Service (GWCS, see 4.94—4.99 GHz).
Opinions Mean Nothing
FCC auctions chief Jerry Vaughan, presenting WCS to prospective bidders, said, "Here is some spectrum. Do whatever you want with it, with a few very minor exceptions. Our opinions mean nothing 15 seconds after you buy the spectrum."
The April 1997 auction of 128 WCS licenses to 17 winning bidders raised more than $13 million for the Treasury, an amount far less than predicted by congressional budget experts. Some licenses went for as little as $1.00. At this writing, it appears that one of the earliest WCS license winners to place WCS systems in operation is Metricom (see 902—928 MHz).
Various theories about the low receipts emerged. Some charged that the FCC simply had already auctioned more spectrum than the wireless industry could comfortably absorb. Moreover, legislation required the FCC to begin auctioning licenses in these bands no later than April 15, 1997, giving the industry little time to develop equipment or business plans after the WCS allocation order of February 19, 1997. It required the FCC to deposit all funds raised no later than September 30, 1997, ruling out long-term payment plans.
A reason for the relative lack of interest in WCS licenses probably was the FCC's insistence on extremely tight out-of-band emissions limits for WCS transmitters, in order to prevent interference from WCS to reception of the satellite Digital Audio Radio Service (SDARS or DARS) in 2320—2345 MHz. The filtering and shielding necessary to achieve the limits could make WCS devices too unwieldy and expensive to compete with tiny wireless phones. Wireless fixed data, telephone, and entertainment transmission, however, remain a possibility.
"WCS licensees themselves will determine the specific services they will provide within their assigned spectrum and geographic areas," the FCC said. "The services that can be provided, however, will be subject to specific technical rules…to prevent interference to other services. We emphasize that with the current state of technology there is a substantial risk that these rules will severely limit, if not preclude, most mobile and mobile radiolocation uses. Fixed uses will be less severely affected, but still will require equipment that will meet technical standards higher than those used for similar purposes on comparable bands, and therefore may be more costly."
The FCC later relented somewhat and relaxed the out-of-band emissions limits in order to accommodate prospective WCS licensees who wanted to deploy services based on the Personal Access Communications System (PACS), a low-mobility handheld phone standard. No PACS-based WCS systems are operating.
According to Bell Atlantic NYNEX Mobile, which won major eastern WCS markets for a total of $1.6 million, "some of the potential uses for the new spectrum include data communications, Internet access, and low mobility wireless services for customers who need 'walkaround' wireless access in a limited geographic area, such as a local neighborhood or business campus."
Licensing
The FCC licensed WCS as two 10-MHz channel blocks plus two 5-MHz blocks. "The record suggests that the 10-MHz channel blocks represent the minimum amount of spectrum needed to support certain data and wireless local loop services, including wireless Internet access," the agency said.
"In addition, we believe that providing for 10 MHz of spectrum on a paired basis would allow for the introduction of both one-way and two-way services and would facilitate the implementation of a variety of technologies. In the spectrum adjacent to the satellite DARS band, however, we believe that WCS mobile operations may be prohibitively expensive and technologically infeasible for a substantial period of time."
The WCS channel blocks include A, 2305—2310 MHz and 2350—2355 MHz; B, 2310—2315 MHz and 2355—2360 MHz; C, 2315—2320 MHz; and D, 2345—2350 MHz.
The A and B blocks were licensed in 53 Major Economic Areas (MEAs) and the C and D blocks were licensed in six continental Regional Economic Area Groupings (REAGs), plus six other REAGs for U.S. possessions plus Alaska, Hawaii, and the Gulf of Mexico.
Like other holders of FCC licenses for exclusive territories, WCS licensees can partition, or assign parts of their geographic service areas, and disaggregate portions of their licensed spectrum to other entities, including those that did not participate in the auction. These geographic partitioning and spectrum disaggregation rules, "while not a substitute for licensing directly by the Commission, nevertheless will help to eliminate market entry barriers…by providing smaller, less capital-intensive areas and spectrum blocks which are more accessible by small business entities," the FCC said.
WCS licensees were granted the most liberal construction, or build-out requirement ever adopted by the FCC. Licensees are simply required to provide substantial service to their service area within 10 years. "Given the undeveloped nature of equipment for use in this band and the technical requirements we are adopting to prevent interference, we are concerned that strict construction requirements might have the effect of discouraging participation in the provision of services over the WCS spectrum," the Commission said.
It suggested that substantial service could include four links per million population for fixed WCS services, or 20 percent coverage of the population in the service area for mobile services. Other possible substantial service factors could include specialized or technologically sophisticated service or service to niche markets or unserved areas.
WCS Satellites
In late 1998, WCS Radio Inc. of Menlo Park, California, a venture associated with WCS licensees, applied for FCC permission to use their licenses to provide SDARS service from two geostationary spacecraft in 2310—2320 MHz and 2345—2360 MHz.
The FCC’s WCS rules do in fact contemplate SDARS in some of the WCS spectrum, as one of a number of possible WCS services. In theory, licensees participating in WCS Radio were in a desirable position because they required neither new spectrum allocations, new service rules, nor auctions in order to establish rights to provide SDARS services.
WCS Radio would have provided "up to 100 channels of high quality music and talk radio and innovative data services throughout the contiguous United States," the company told the FCC. "Users in motor vehicles, on boats, in the air, on foot, or in buildings will be able to receive the programming with a low-cost receiver and a small low-gain, omnidirectional antenna. The digital technology combined with a unique scheme of path diversity and time diversity will provide music quality superior to current and proposed terrestrial radio systems and will rival the quality of stereo compact disks."
The company intended to use its WCS frequencies for terrestrial repeaters that would rebroadcast its satellite signal to improve reception. Service was supposed to begin in 2002. But in May 1999, revealing significant, if brief, information about its future intentions, WCS Radio withdrew its proposal from FCC consideration.
"WCSR discovered both that there were more obstacles to launching an SDARS system than anticipated, and that the market for SDARS services was changing," the company said. "WCSR has now determined that terrestrial-based WCS networks could create a more robust and cost-effective system for delivering audio, Internet and streaming services to handheld and mobile devices than could a satellite system operating under the restraints imposed by WCS licensees."
The 2305—2310 MHz portion of the WCS allocation is shared on a secondary basis with Amateur Radio, one of the few places in the spectrum where ham operators are supposed to share with auction winners.
***** (End of historical information from Wireless Spectrum Finder)
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Paired Frequency Bands |
| Paired Bands | Use | Service | Table |
| 2305 - 2310 MHz | WCS A block | Fixed | N |
| 2350 - 2355 MHz | WCS A block | Fixed | N |
| 2310 - 2315 MHz | WCS B block | Fixed | N |
| 2355 - 2360 MHz | WCS B block | Fixed | N |
Frequency Bands |
| Band | Use | Service | Table |
| 2315 - 2320 MHz | WCS C block | Fixed | N |
| 2345 - 2350 MHz | WCS D block | Fixed | N |
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Satellite Digital Audio Radio Service (SDARS) (Sirius & XM)
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Sirius and XM, which are now one company, use this band to transmit digital radio from their satellites and also from ground-based transmitters (terrstrial repeaters) that fill in coverage gaps due to building and terrain blockage of the satellite signals.
According to the FCC (FCC 10-82), "The Commission's rules define SDARS - commonly known as "satellite radio" – as "[a] radiocommunication service in which audio programming is digitally transmitted by one or more space stations directly to fixed, mobile, and/or portable stations, and which may involve complementary repeating terrestrial transmitters, telemetry, tracking and control facilities." Thus, SDARS is primarily a satellite-delivered service in which programming is sent directly from satellites to subscriber receivers either at a fixed location or in motion. Because a direct line of sight is generally required in order to receive an acceptable satellite signal, ground-based terrestrial repeaters are used in many areas to re-transmit the same signals provided by satellites directly to subscribers in order to maintain adequate signal power. These areas include "urban canyons" between tall buildings, heavily foliaged areas, tunnels, and other places where obstructions could limit satellite visibility or cause multipath interference from reflected signals.
"Licenses to provide SDARS within the United States were awarded by auction in early April, 1997. The two winners of the auction – XM and Sirius – were each assigned 12.5 megahertz of spectrum for their exclusive use on a primary basis. XM and Sirius launched their satellites and began commercial operations in 2001 and 2002, respectively. As of March 31, 2010, Sirius XM reported it had 18,944,199 subscribers in the conterminous United States.
"On August 5, 2008, the Commission approved the merger of XM and Sirius, which have subsequently combined to form a merged entity called "Sirius XM." In the merger proceeding, the Commission found that significant engineering differences in the XM and Sirius infrastructures make integration of the two systems difficult in the short term. In addition, the Commission noted that XM and Sirius had each invested significantly in their existing infrastructure, with the expectation of operating this infrastructure for years to come. Thus, despite the merger of the two companies, the XM and Sirius satellite and repeater infrastructures will operate as separate, legacy systems, at least in the near term.
"Sirius XM offers hundreds of channels of music, entertainment, news, and sports programming on the Sirius and XM satellite radio networks, as well as weather and data information services for maritime, aeronautical, and other purposes. SDARS radio receivers are used in cars, trucks, boats, aircraft, and homes – and are available for portable use..."
Acccording to SiriusXM, their satellite signals cover the 48 contiguous states, and 200 miles "off shore."
Historical Information on SDARS
The following is historical information on SDARS from Benn Kobb's 2001 book Wireless Spectrum Finder. That book is now (c) SpectrumWiki.com:
*****
The principal worldwide band for audio broadcasting direct to the public from satellites (Broadcasting-Satellite Service (Sound) or BSS) is the so-called L-band, 1452—1492 MHz.
That band falls within aeronautical test telemetry spectrum in the U.S. (see 1435—1525 MHz).
As an alternative, the International Telecommunication Union (ITU) allocated the S-band, 2310—2360 MHz, for domestic satellite audio broadcasting in the U.S. Other nations, especially Canada, criticized this action as detrimental to the realization of a uniform worldwide service in the L-band.
The ITU also allocated 2520—2670 MHz for BSS national and regional systems for community reception. (India and Mexico also are authorized to use the S-band for BSS.)
Against ferocious opposition from conventional broadcasters, the FCC eventually allocated 2320—2345 MHz to satellite Digital Audio Radio Services (SDARS or DARS). “Satellite DARS will provide continuous radio service of compact disc quality for all listeners and will offer an increased choice of over-the-air audio programming,” the FCC said.
No other significant terrestrial U.S. users are in the S-band, but adjacent countries operate terrestrial fixed point-to-point, fixed point-to-multipoint, and aeronautical mobile telemetry systems in the band. Satellite DARS operators must take precautions to avoid interference with the systems of other nations.
Sirius and XM
There are two SDARS licensees : Sirius Satellite Radio (2320—2332.5 MHz), formerly Satellite CD Radio and XM Satellite Radio (2332.5—2345 MHz), formerly American Mobile Radio.
These companies won their licenses by bidding $83 million and $89 million, respectively, at an April 1997 auction. The FCC concluded that only enough spectrum existed in the S-band for two SDARS licensees of 12.5 MHz each. The FCC requires that SDARS receivers be capable of picking up broadcasts from both of the licensees.
The licensees must deploy hundreds of terrestrial repeaters, ground transmitters that relay broadcasts from satellites. Most of the gap-fillers will be in urban areas where obstructions inhibit satellite reception.
Sirius will use three satellites in inclined elliptical orbits will offer a service directed mainly to vehicle radios. Sirius-1 and Sirius-2 had been launched at this writing. The major investors in Sirius include Ford and Loral.
XM will use two geostationary satellites (officially designated “Rock” and “Roll”) that are directed both to vehicle and portable radios. XM’s major investors include GM and its DirecTV business; Clear Channel Communications; and Liberty Media, in addition to its founder, Motient Corp., formerly American Mobile Satellite Corp.
Uplink stations in 7.025—7.075 GHz feed these satellites. They use frequencies in the S-band in 3.7—4.2 GHz, and 5.925—6.425 GHz for telemetry and control, operation during transfer to final orbit, and for contingency purposes.
Other SDARS-Related Issues
Sirius and XM might have faced competition from SDARS service in the Wireless Communications Service (WCS) band. A group of WCS licensees applied for permission to use their licenses to provide SDARS (see 2305—2310 MHz). They later abandoned the idea.
The FCC licensed, originally on an experimental basis only, the WorldSpace SDARS system to broadcast in the L-band (see 1435—1525 MHz). It later granted full authorization to the Washington, D.C.-based WorldSpace, but does not permit the company to serve U.S. audiences.
NASA’s Goldstone Solar System Radar operates at 2320 MHz and 8.56 GHz in the Mojave Desert northeast of Los Angeles. Scientists used it to observe Comet Hyakutake when it passed within 9.3 million miles of Earth in 1996.
SDARS interference is expected to make radar astronomy operations at 2320 MHz “nearly impossible,” according to NASA’s Jet Propulsion Laboratory.
The 2310—2390 MHz spectrum is one of many restricted bands in which the FCC Part 15 rules permit unlicensed devices to emit only very low level emissions.
***** (End of historical information from Wireless Spectrum Finder)
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Industrial, Scientific, and Medical Devices (ISM, FCC Part 18)
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Part 18 (section 18.301) of the FCC rules designate certain bands for high-power Industrial, Scientific, and Medical (ISM) devices. These devices generate significant radio energy, but not for telecommunications purposes. Examples includes microwave ovens, industrial heaters, medical diathermy, jewelry cleaners, and RFID tags.
ISM devices may be operated in most frequency bands subject to strict power limits, but are allowed unlimited power in these eleven specially-designated ISM bands.
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Unlicensed bands
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Although these bands are allocated for ISM use, e.g. microwave ovens and industrial equipment, a major use has been unlicensed (Part 15) systems such as Wi-Fi, Bluetooth, and ZigBee. In the period 1995-2005, most of the cordless phones marketed in the US were in the 902-928 MHz band, but conflicts with the other uses and availability of DECT equipment has greatly decreased sales of 902-928 MHz cordless phones.
The rules for these bands sprung from FCC Docket 81-413 which sought to end an implicit prohibition of spread spectrum/CDMA technology that resulted from a focus on FDMA spectrum uses. This resulted in rules adopted in 1985 that allow unlicensed spread spectrum systems to use these bands for almost any possible application subject to a 1W power limit and a power spectral density limit. Initial applications, however, were limited to frequency hopping and "direct sequence" modulations, the latter being subject to ill-defined spreading and processing gain requirements.
An FCC rulemaking in 2002, in ET Docket No. 99-231, dropped the spreading and processing gain requirements, and permitted any digital modulation that meets the power and power spectral density limits. The immediate effect was to authorize Wi-Fi products under standard IEEE 802.11g. Subsequent Wi-Fi standards, including n and ac, were eligible for certification with no further rule changes.
Bluetooth is authorized under the original 1985 frequency hopping provisions.
The 2400 and 5800 MHz bands are used for Wi-Fi.
A good history is "The Innovation Journey of Wi-Fi: The Road To Global Success" by Wolter Lemstra, Vic Hayes, John Groenewegen; Cambridge University Press, 2010.
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Frequency Bands |
| Band | Use | Service | Table |
| 902 - 928 MHz | 900 MHz unlicensed band | - | - |
| 2400 - 2483.5 MHz | Unlicensed band (commonly used by Wi-Fi) | - | - |
| 5725 - 5850 MHz | Unlicensed band (commonly used by Wi-Fi) | - | - |
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802.11/WLAN/Wi-Fi/WiGig
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Wireless LANS utilize various channels in the 2.4, 5, and 6 GHz bands (multiple countries), and (in theory) the 3.6 GHz band (U.S. only). For a list of which channels are available in which regions, refer to the Wikipedia article.
Wi-Fi is a trademark permitted for devices that are based upon a published standard of the IEEE 802.11 committee and that have been certified by the Wi-Fi Alliance. Wi-Fi is presently incorporated in about three billion devices. Wireless cash registers were one of the earliest applications of what is now Wi-Fi.
Wi-Fi devices operate on an unlicensed basis, generally meaning they cannot cause interference to licensed services, and must accept any interference caused to them. Wi-Fi shares bands with other unlicensed or ISM devices, such as cordless phones at 2.4 and 5.8 GHz and microwave ovens at 2.4 GHz.
Some of the key patents related to Wi-Fi are credited (in the courts at least) to the Commonwealth Scientific and Industrial Research Organisation (CSIRO) in Australia, which has collected over $400 million in royalties and legal settlements over patent rights.
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Frequency Bands |
| Band | Use | Service | Table |
| 2400 - 2495 MHz | Wireless LANs | - | - |
| 3655 - 3700 MHz | Wireless LANS (U.S. only; standardized but not used) | - | - |
| 4910 - 4990 MHz | Wireless LANs (Japan) (U.S. public safety 4940-4990) | - | - |
| 5030 - 5090 MHz | WLANs (Japan, 2002-2017) | - | - |
| 5150 - 5350 MHz | Wireless LANs (U-NII-1 and U-NII-2A) | - | - |
| 5470 - 5895 MHz | Wireless LANs (U-NII-2C, U-NII-3, U-NII-4) | - | - |
| 5925 - 7125 MHz | Wireless LANs (U-NII-5, U-NII-6, U-NII-7, U-NII-8) | - | - |
| 42.39 - 46.71 GHz | Wireless LANs (WiGig) | - | - |
| 57.24 - 74.52 GHz | Wireless LANs (WiGig) | - | - |
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NASA Tracking and Data Relay Satellite System (TDRSS)
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According to NASA:
The Tracking and Data Relay Satellites (TDRS) comprise the communication satellite component of the Tracking and Data Relay Satellite System (TDRSS). TDRSS is a communication signal relay system which provides tracking and data aquisition services between low-earth orbiting spacecraft and control and/or data processing facilities. The system is capable of transmitting to and receiving data from spacecraft over at least 85% of the spacecraft's orbit.
The TDRSS space segment consists of six on-orbit Tracking and Data Relay Satellites located in geosynchronous orbit. Three TDRSs are available for operational support at any given time. The operational spacecraft are located at 41°, 174° and 275° West longitude. The other TDRSs in the constellation provide ready backup in the event of a failure to an operational spacecraft and, in some specialized cases, resources for target of opportunity activities.
The TDRSS ground segment is located near Las Cruces, New Mexico, known as the White Sands Complex. Forward data is uplinked from the ground segment to the TDRS and from the TDRS to the spacecraft. Return data is downlinked from the spacecraft via the TDRS to the ground segment and then on to the designated data collection location.
The Tracking and Data Relay Satellite (TDRS) Project is providing follow-on and replacement spacecraft necessary to maintain and expand the Space Network. The contract to build three additional TDRS spacecraft, known as TDRS K, L, and M, was awarded to Boeing Space Systems in December 2007. TDRS K launched January 30, 2013, and TDRS L launched January 23, 2014. TDRS M's launch readiness date is scheduled for 2015. The contract also has options for one additional spacecraft, TDRS N. In addition to building the TDRS K, L, and M spacecraft, the contract also includes the modifications to the White Sands Complex (WSC) ground system required to support these new spacecraft.
The TDRS Project, established in 1973, is responsible for the development, launch, and on-orbit test and calibration of TDRS spacecraft. There have been four procurements of TDRS spacecraft, which include the Basic Program (TDRS F1-F6), the Replacement Program (TDRS F7), the TDRS H,I,J Program, and the TDRS K,L,M Program. TDRS Flight 7 was a replacement for Flight 2, which was lost aboard Challenger in 1986. The first seven spacecraft (TDRS F1-F7) are referred to as the First Generation, the H,I,J series are called the Second Generation, and the K,L,M series are known as the Third Generation. TDRS F1-7 spacecraft were built by TRW (now Northrop Grumman) in Redondo Beach, CA. The TDRS F8-10 (H,I,J) spacecraft were built by Hughes (now Boeing) in El Segundo, CA.
The NASA Space Network consists of the on-orbit telecommunications TDRS satellites, placed in geosynchronous orbit, and the associated TDRS ground stations, located in White Sands, New Mexico and Guam. The TDRS constellation is capable of providing nearly continuous high bandwidth (S, Ku, and Ka band) telecommunications services for expandable launch vehicles and user spacecraft in low Earth orbit. Examples include: the Hubble Space Telescope, the Earth Observig Fleet and the International Space Station. The TDRS System is a basic agency capability and a critical national resource.
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Paired Frequency Bands |
| Paired Bands | Use | Service | Table |
| 2025.8 - 2117.9 MHz | S-band Single Access (TDRS transmit) | Space Operation | F |
| 2200 - 2300 MHz | S-band Single Access (TDRS receive) | Space Research (space-to-Earth) | F |
| 2103.4 - 2109.4 MHz | S-band Multiple Access (TDRS transmit) | Space Operation | F |
| 2285 - 2290 MHz | S-band Multiple Access (TDRS receive) | Space Operation (space-to-Earth) | F |
| 13.4 - 14.05 GHz | TDRS downlink | Space Research | F |
| 14.6 - 15.25 GHz | TDRS uplink | Space Research (Earth-to-space) | F |
| 13.75 - 13.8 GHz | Ku-band Single Access (TDRS transmit) | Space Operation | F |
| 14.891 - 15.116 GHz | Ku-band Single Access (TDRS receive) | Space Research (space-to-Earth) | F |
Frequencies |
| Frequency | Bandwidth | Use | Service | Table |
| 2036 MHz | - | TDRS command uplink | Space Operation | F |
| 2211 MHz | - | TDRS telemetry downlink | Space Operation | F |
| 13.731 GHz | - | TDRS telemetry downlink | Space Operation | F |
| 14.785 GHz | - | TDRS command uplink | Space Operation | F |
| 15.15 GHz | - | TDRS reference frequency signal uplink | Space Operation | F |
Frequency Bands |
| Band | Use | Service | Table |
| 25.25 - 27.5 GHz | Ka-band Single Access (TDRS receive) | Space Research | F |
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Amateur Radio (13 cm Band)
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The band 2300-2450 MHz is allocated on a secondary basis to amateur radio in all three ITU regions. According to the ITU, this band is used for short-range communications and for experimentation.
By virtue of 5.282, in the band 2400-2450 MHz, the amateur-satellite service may operate subject to not causing harmful interference to other services operating in accordance with the Table.
In the United States, only the sub-bands 2300-2310 and 2390-2450 MHz are allocated to the amateur service. The ARRL has adopted the following band plan:
2300.0-2303.0 High-rate data
2303.0-2303.5 Packet
2303.5-2303.8 TTY packet
2303.9-2303.9 Packet, TTY, CW, EME
2303.9-2304.1 CW, EME
2304.1 Calling frequency
2304.1-2304.2 CW, EME, SSB
2304.2-2304.3 SSB, SSTV, FAX, Packet AM, Amtor
2304.30-2304.32 Propagation beacon network
2304.32-2304.40 General propagation beacons
2304.4-2304.5 SSB, SSTV, ACSSB, FAX, Packet AM, Amtor experimental
2304.5-2304.7 Crossband linear translator input
2304.7-2304.9 Crossband linear translator output
2304.9-2305.0 Experimental beacons
2305.0-2305.2 FM simplex (25 kHz spacing)
2305.20 FM simplex calling frequency
2305.2-2306.0 FM simplex (25 kHz spacing)
2306.0-2309.0 FM Repeaters (25 kHz) input
2309.0-2310.0 Control and auxiliary links
2390.0-2396.0 Fast-scan TV
2396.0-2399.0 High-rate data
2399.0-2399.5 Packet
2399.5-2400.0 Control and auxiliary links
2400.0-2403.0 Satellite
2403.0-2408.0 Satellite high-rate data
2408.0-2410.0 Satellite
2410.0-2413.0 FM repeaters (25 kHz) output
2413.0-2418.0 High-rate data
2418.0-2430.0 Fast-scan TV
2430.0-2433.0 Satellite
2433.0-2438.0 Satellite high-rate data
2438.0-2450.0 WB FM, FSTV, FMTV, SS experimental
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Frequency Bands |
| Band | Use | Service | Table |
| 2300 - 2450 MHz | Amateur radio 13 cm band | AM | N |
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Arecibo Planetary Radar
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The Arecibo radio telescope in Puerto Rico is used in radar mode, at a frequency of 2380 MHz, to map out the surface structure and orbits of planets, planetary moons, asteroids, comets, and the Moon. The radar can be used to detect near-Earth asteroids that could pose a threat to our planet.
The planetary radar is the most powerful transmitter on Earth, combining a 1 million watt transmitter with the 76 dBi forward gain of the giant Arecibo 1000' speherical reflector, to provide about 40 trillion watts of effective isotropic radiated power.
The radar transmitter has been used on several occasions to broadcast messages to space, in the hopes that the messages may one day be intercepted by extraterrestrial civilizations.
The Arecibo telescope is also capable of transmitting at 430 and 46 MHz, frequencies which are used for probing the Earth's magnetosphere, ionosphere, and upper atmosphere.
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Frequency Bands |
| Band | Use | Service | Table |
| 2370 - 2390 MHz | Arecibo Planetary Radar | Radiolocation | F |
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This Arecibo radar image in delay-Doppler coordinates of the south pole region of the Moon was made at Arecibo in a search for ice in permanently shadowed areas. It is 400 km in each coordinate and the original image has a resolution of 500 m in delay (vertical) and 580 m in Doppler (horizontal). The illumination is from the top (so range increases downward), and increasing Doppler frequency is towards the left. The approximate location of the south pole is indicated by the cross. The search was for the characteristic radar signature of ice, high backscatter cross section and high circular polarization ratio. No clear indication of ice was found, although a small number of areas with anomalous radar properties need further investigation. These lunar investigations were done by N. J. Stacy as part of his Cornell Ph.D. thesis.
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