Exhibit

0263-EX-PL-2000 Text Documents

COMSAT Corporation/COMSAT Mobile Communications

2000-12-06ELS_43231

                    ID :                                 DEC 0500          11:37 No .001 P .02

                                                               FCC Form 442 Exhibit 1: CMC
                                                                                   Page 1/3




                                       EXLLLBIT 1

                            EQUJPMENT DESCRIPTION


PROGRAM DESCRIPTION

Comsat Mobile Communications (CMC) will be operating one fixed Satcom pallet
equipped with Honeywell Electronics Avionics at their INMARSAT ground earth station
at Santa Paula, CA. The equipment will be operated for the purpose of,

a) Test and demonstrate operation of an INMARSAT aircraft earth station (AES) with
   terrestrial public switched telephone and data systems (PSTN and PSIDN) inter{aces
   for voice/data/fax applications.

b) Provide capability to monitor vendor changes, training capability for the
   commissioning and Maintenance Terminal (CMT), monitoring ofLand Earth Station
   (LES)/AES interface and confirm AES preference programming specifications.

The equipment shall opcrate in the Marine and Acronautical Mobile Satceilite band of
frequencies. Demonstration of the operational capability of this equipment requires
transmitting. No "FOR JJIRE" communications are to be provided during any use of this
equipment.

DIGITAL VOICE AND DATA

The equipment shall transmit on channel of digital voice or high speed data using 21
Kb/sec (10.5) A—QPSK modulation. The system shall use a high gain stationary helix test
antenna, In addition, low speed data will be transmitted using an A—BPSK modulation,
All modulation complies with aviation standards, Ground communication services shall be
provided by CMC and other INMARSAT land earth station operators (LESOs) as
required.

OPERATING DETAILS

The bands comprising 1626.5 to 1660,.5 MHz will be used. Specific frequencies and
operating schedules will be coordinated with Inmarsat, in cooperation with CMC and
other INMARSAT LESOs.

RF Power Output

The maximum RF power output of the equipment will be 60 Watts per carrier (17.8 dBW
peak).


                       ID:                               DEC O5 °00           11:38 No .001 P .03

                                                               FCC Form 442 Exhibit 1: CMC
                                                                                   Page 2/3



Antenna Gwain

A high gain helix antenna shall be used to provide a gain of 12 dBic and half power beam
width of 28 degrees.

EIRP

The maximum equivalent isotropic radiated power (KIRP) shall be 27.6 dBW (peak) {17.8
19.8).

Emission Types

                                                                   Rate 1/2
       !mission        Modulation          Symbol               Convolutionally
         Type            Type               Rate                 Encoded Rate

       840HGID         A—BPSK              600 baud             (600 b/sec)
       1K68GID          A—BPSK             1200 baud            (1200 b/sec)
       3K36GID         A—BPSK              2400 baud            (2400 b/sec)
       4K80G)L)        A—QPSK              2400 baud            (4800 b/sec)
       6K72GIW         A—QPSK              4.2 kbaud            {(8400 b/sec)
       10KSGID         A—QPSK              5.25 kbaud           {(10.5 kb/sec)
       21KOGIW         A—QPSK              10.5 kbaud           (21.0 kb/sec)



Modulation Methods

Type              Description

A—QPSK            Aviation Quadrature Phase Shift Keying uses a
                  specific form of Offset QPSK where the modulationfiltering is
                  optimized for satellite communications with aviation applications
                  (Reference: "Quaternary Transmission Over Satellite Channels with
                  Cascaded Non—Linear Elements and Adjacent Channel Interference" by
                  Russel Fang in TIEEE Transactions on Communications, May 1981,
                  Vol. COM—29, No. 5, pp. 567—581.}

A—BPSK            Aviation Binary Phase Shift Keying uses a specific form of differentially
                  encoded BPSK where in—phase and quadrature channels are usedto
                  transmit alternate symbols. (Referenced: "Differential Detection With
                  Intersymbol Interference and Frequency Uncertainty" by J.H. Wintore
                  in 1EEE Transactions on Communications, January 1984, Vol. Comin—
                  32, No. 1, pp. 25—33.)


                        ID :                                  DEC 0500          11:38 No .001 P .04

                                                                    FCC Form 442 Exhibit 1: CMC
                                                                                        Page 3/3

NECESSARY BANDWIDT!HL

Radiated bandwidth from the equipment is controlled by the use of raised cosine filters in the
transmitter. ‘The A—QPSK are signals subjected to either a 60% or 100% raised cosine filter.
A 40% raised cosine filter is used for the A—l3PSK signals.

The associated necessary bandwidth calculation is:

   BW=—L/T (1+1)
   Where 1/7T is the symbel transmission rate in symbols per second and r is the roiloff factor.

Symbol Rate      Modulation       Rolloff       Bandwidth
   (Baud)        _ Type             Lr            (BWw)
    600          A—BPSK             0.4         0.840 KHz
   1200          A—BPSK             0.4         1.680 KHz
   2400          A—BPSK             0.4         3.300 Kl1z
   2400          A—QPSK             1.0         4.800 KHz
   4200          A—QPSK             0.6         6.720 KHz
   5250          A—QPSK             1.0         10.5 KHz
   10. 5k        A—QPSK             1.0         21.00 K1z



Document Created: 2000-12-06 09:36:03
Document Modified: 2000-12-06 09:36:03

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