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ADEC Network Transponder Technical Information

Design Parameters:

  1. The choice of transponders shall be limited to Ku-band.
  2. The transponder shall be provided on a satellite which is located in the domestic orbital arc between 75 dgrs W and 125 dgrs W to facilitate access by ADEC uplink equipment located on the East and West Coasts.
  3. The transponder shall be capable of delivering the following services:
    1. Wireless Internet transmitted from an ADEC member hub
    2. Digital broadcast quality transmission of video/audio programming to Direct Broadcast Satellite (DBS), cable and television network providers.
    3. SCPC channels which are accessible from ADEC member digital uplink facilities. These channels may be dedicated to single members, shared by one or more members or offered on an occasional use basis to members.
  4. The ADEC transponder shall be controlled from facilities which are located at an ADEC member institution

Potential Satellites:

The following satellites have been identified as potential candidates to host one or more ADEC transponders:

TELSTAR 5 (Loral Skynet)
Orbital Location:    97 degrees West Longitude
Ku-band Transponder Bandwidth:    27 & 54 MHz
TWTA Power:    100 Watts nominal
Estimated End of Life (EOL):    2009
Peak EIRP:    50.5 dBW
Typical EIRP:
   CONUS:    48.3 dBW
   Alaska:    39.1 dBW
   Hawaii:    46.4 dBW
   Puerto Rico &USVI:    44.9 dBW
TELSTAR 6 (Loral Skynet)
Orbital Location:    93 degrees West Longitude
Ku-band Transponder Bandwidth:    27 & 54 MHz
TWTA Power:    100 Watts nominal
Estimated End of Life (EOL):    2011
Peak EIRP:    50.5 dBW
Typical EIRP:
   CONUS:    48.3 dBW
   Alaska:    39.1 dBW
   Hawaii:    46.4 dBW
   Puerto Rico & USVI:    44.9 dBW
   Mexico:    43.6 dBW
   Southern Canada:    44.3 dBW
   Caribbean:    43.4 dBW
SATMEX 5/K-2 Beam (Loral/Telephonica Autrey)
Orbital Location:    116.8 degrees West Longitude
Ku-band Transponder Bandwidth:    36 MHz
TWTA Power:    132.5 Watts
Estimated End of Live (EOL):    2014
Peak EIRP:    48.7 dBW
Coverage (Regional EIRP tbd)
   Southern Canada and Maritime Provinces
   Puerto Rico & USVI
   Eastern and Western Caribbean
   Central America

Loral has a number of 27 MHZ transponders available on TELSTAR 5. The opening price offer is $175,000/month for pre-emptible service. The opening price offered for 54 MHZ service on TELSTAR 5 is $255,000/month. SatMex 5 will be available for service during the First Quarter of 1999. The satellite will carry eight Ku-band transponders for CONUS service (K-1), eight for CONUS and South American service (K-2) and eight switchable transponders. The opening price for 36 MHz service on the K-2 transponders is $195,000/month. Loral will be launching TELSTAR 6 into orbit at 93 degrees West Longitude in First Quarter of 1999. This satellite will be identical to TELSTAR 5. Loral and its partners now hold a majority share of SATMEX (formerly the Mexican satellite communications parastatal ) and Orion which provides VSAT satellite communications service to Europe and Latin America. Ownership of space segment on Loral equipment would give ADEC proprietary pricing advantages for Orion and SATMEX services. Protected service transponders are available on the Loral and Loral/SatMex satellites.

GE-3 (GE Americom)
Orbital Location:    87 degrees West Longitude
Ku-band Transponder Bandwidth:    36 MHZ
TWTA Power:    60 Watts
Estimated End of Life (EOL):    2012
Peak EIRP:    50.0 dBW
Typical EIRP:
   CONUS:    46 dBW
   Alaska:    n/a
   Hawaii:    40 dBW
   Puerto Rico/USVI    n/a (C-band coverage only)
GE-5 (GE Americom)
Orbital Location    79 degrees West Longitude
Ku-band Transponder Bandwidth:    54 MHz
TWTA Power:    55 Watts
Estimated End of Life (EOL)    2011
Peak EIRP    49.± dBW
Coverage (Regional EIRP tbd)
   Southern Canada
   Northern Mexico

GE Americom is the principal marketing agent for transponders on GE-3 which are offered for an opening price of $210,000/month subject to discounts for long term contract agreements. Loral Skynet owns two transponders on GE-3 which are available for sale for an opening price of $165,000.month. PBS has indicated that it would like to dispose of two of its seven transponders on GE-3. Two brokers, ISIS and The Spaceconnection, Inc., both marketing agents for these transponders, have shown an interest in working with ADEC and have indicated that a price of around $155,000/month could be negotiated. All prices have been provided for pre-emptible service.

Conditional protected service is available, however, GE-3 serves as a back-up satellite for GE-2 which provides all of its Ku-band Transponders to Primestar DBS service. A catastrophic failure of GE-2 would result in all tenants on GE-3 being removed or relocated. Inquires made to Hughes Communications, DirecTV and GE Americom indicate that the PrimeStar Ku-band assets on GE-2 will not be release for sale as a result of the DirecTV-PrimeStar merger.

The primary uses for GE-5 (launched November 28, 1998) are Satellite New Gathering (SNG), occassional services, VSAT, business television and broadband Internet market services. A dedicated pool of occassional transponders will be made available to news costumers.

Link Budgets:

A link budget has been prepared for Multiple Channel Per Carrier (MCPC) service. A DigiCipher II (DCII) or MPEG II/DVB multiple channel encoder will be operated at an ADEC member institution which will transmit to the ADEC transponder.

The design will support MCPC video channels in NTSC quality as well as the transmission of data (up to 9 Mb/s isochronous ).

After all of the overhead is taken into consideration for Forward Error Correction (FEC -- rate 7/8) and Reed Solomon coding, a final bit rate of 11.81 megabit, in 9.74 MHZ of bandwidth results. Loral will require a guard-band allocation of an additional 1.37 MHZ for a cumulative total bandwidth of 11.11 MHZ.

With a calculated threshold of 7.15 db, C/N on the downlink side, (ie., the minimum signal to noise ratio required for successful operation of the receivers), the following link budget results (based on some assumptions which are very conservative):

Downlink Antenna Diameter:    6 feet (1.8 Meters)
Antenna Noise Temperature:    28 deg C (SWAG)
Antenna Gain:    45.99 dBi
Electronics Temperature:    85 deg C. (Conservative)
I.F. Bandwidth:    9.75 MHZ
Satellite EIRP (CONUS)    48 dBw
Back-off:    15 dBw
Downlink G/T:    25.06
Downlink Eb/NO (C/N)    10.31 dB

Single Channel Per Carrier (SCPC) Service:

Investigation of other digital transponder tenants such as the National Technology University (NTU) indicates that an allocation of approximately 3 MHZ of bandwidth for each SCPC channel would provide sufficient transmission and security bandwidth for effective operation of an ADEC transponder if ADEC controlled the entire transponder. Loral engineers have advised us that a dedication of between 2.75 and 3.00 MHZ of bandwidth (including security) will provide sufficient bandwidth to deliver broadcast quality (1.83 Mega-symbols/second) video. Higher resolution transmissions would require the dedication of greater bandwidth but the quality of the video transmission in 2.75-3 MHZ of bandwidth would be comparable to DBS quality.


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Last Updated: June 25, 2002