Sec. 25.202  Frequencies, frequency tolerance and emission limitations.

    (a)(1) Frequency bands. The following frequencies are available for 
use by the fixed-satellite service. Precise frequencies and bandwidths 
of emission shall be assigned on a case-by-case basis.

                                                                        
------------------------------------------------------------------------
                                                          Earth-to-space
                  Space-to-Earth (GHz)                         (GHz)    
------------------------------------------------------------------------
3.7-4.2 \1\.............................................  \1\ 5.925-6.42
                                                                 5      
10.95-11.2 \1\..........................................  \4\ 13.75-14.0
11.45-11.7 \2\..........................................  \5\ 14.0-14.2 
11.7-12.2 \3\...........................................  14.2-14.5     
17.7-19.7 \1\...........................................  \1\ 27.5-29.5 
19.7-20.2...............................................  29.5-30.0     
------------------------------------------------------------------------
\1\ This band is shared coequally with terrestrial radiocommunication   
  services.                                                             
\2\ Use of this band by the fixed-satellite service is limited to       
  international systems, i.e., other than domestic systems.             
\3\ Use of this band by the fixed-satellite service in Region 2 is      
  limited to national and subregional systems. Fixed-satellite          
  transponders may be used additionally for transmissions in the        
  broadcasting-satellite service.                                       
\4\ This band is shared on an equal basis with the Government           
  radiolocation service, grandfathered space stations in the Tracking   
  and Data Relay Satellite System, and until January 1, 2000, spaceborne
  sensors.                                                              
\5\ In this band, stations in the radionavigation service shall operate 
  on a secondary basis to the fixed-satellite service.                  

    (2) The following frequencies are available for use by the 
Radiodetermination Satellite Service:

1610-1626.5 MHz: User-to-Satellite Link
2483.5-2500 MHz: Satellite-to-User Link


Fixed-Satellite service frequencies may be used for links between 
radiodetermination satellites and control centers, including the 
following designated bands, subject to the Rules in this subpart:

5150-5216 MHz: Satellite-to-Control Center Link
6525-6541.5 MHz: Control Center-to-Satellite Link


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    (3) The following frequencies are available for use by the non-
voice, non-geostationary mobile-satellite service:

137-138 MHz: space-to-Earth
148-149.9 MHz: Earth-to-space
149.9-150.05 MHz: Earth-to-space
399.9-400.05 MHz: Earth-to-space
400.15-401 MHz: space-to-Earth

Until January 1, 1997, the allocations in the 149.9-150.05 MHz and 
399.9-400.05 MHz bands may be used on a secondary basis only. Since the 
399.9-400.05 MHz band is not allocated internationally to the mobile-
satellite service, all operations outside the United States will be on a 
non-interference basis only.

    (4) The following frequencies are available for use by the 1.6/2.4 
GHz Mobile-Satellite Service:

1610-1626.5 MHz: User-to-Satellite Link
1613.8-1626.5 MHz: Satellite-to-User Link (secondary)
2483.5-2500 MHz: Satellite-to-User Link

    (5) The following frequencies are available for use by the inter-
satellite service:

22.55-23.00 GHz
23.00-23.55 GHz
24.45-24.65 GHz
24.65-24.75 GHz

    (6) The following spectrum is available for exclusive use by the 
satellite digital audio radio service:

2320-2345 MHz: space-to-Earth (primary).

    (b) Other frequencies and associated bandwidths of emission may be 
assigned on a case-by-case basis to space systems under this part in 
conformance with Sec. 2.106 of this chapter and the Commission's rules 
and policies.
    (c) Orbital locations assigned to space stations licensed under this 
part by the commission are subject to change by summary order of the 
Commission on 30 days notice. An authorization to construct and/or to 
launch a space station becomes null and void if the construction is not 
begun or is not completed, or if the space station is not launched and 
positioned at its assigned orbital location and operations commenced in 
accordance with the station authorization, by the respective date(s) 
specified in the authorization. Frequencies and orbital location 
assignments are subject to the policies set forth in the Report and 
Order, FCC 83-184, adopted April 27, 1983 in CC Docket No. 81-704 and 
the Report and Order, adopted July 25, 1985 in CC Docket No. 84-1299 as 
modified by the Report and Order, adopted January 19, 1996 in IB Docket 
No. 95-41.
    (d) Frequency tolerance, Earth stations. The carrier frequency of 
each earth station transmitter authorized in these services shall be 
maintained within 0.001 percent of the reference frequency.
    (e) Frequency tolerance, space stations. The carrier frequency of 
each space station transmitter authorized in these services shall be 
maintained within 0.002 percent of the reference frequency.
    (f) Emission limitations. The mean power of emissions shall be 
attenuated below the mean output power of the transmitter in accordance 
with the following schedule:
    (1) In any 4 kHz band, the center frequency of which is removed from 
the assigned frequency by more than 50 percent up to and including 100 
percent of the authorized bandwidth: 25 dB;
    (2) In any 4 kHz band, the center frequency of which is removed from 
the assigned frequency by more than 100 percent up to and including 250 
percent of the authorized bandwidth: 35 dB;
    (3) In any 4 kHz band, the center frequency of which is removed from 
the assigned frequency by more than 250 percent of the authorized 
bandwidth: An amount equal to 43 dB plus 10 times the logarithm (to the 
base 10) of the transmitter power in watts;
    (4) In any event, when an emission outside of the authorized 
bandwidth causes harmful interference, the Commission may, at its 
discretion, require greater attenuation than specified in paragraphs (f) 
(1), (2) and (3) of this section.
    (g) Telemetry, tracking and telecommand functions for U.S. domestic 
satellites shall be conducted at either or both edges of the allocated 
band(s). Frequencies, polarization and coding

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shall be selected to minimize interference into other satellite networks 
and within their own satellite system.
[ 30 FR 7176 , May 28, 1965, as amended at  36 FR 2562 , Feb. 6, 1971;  38 FR 8573 , Apr. 4, 1973;  39 FR 33527 , Sept. 18, 1974;  48 FR 40254 , Sept. 6, 
1983;  50 FR 36079 , Sept. 5, 1985;  51 FR 18445 , May 20, 1986;  51 FR 20975 , June 10, 1986;  54 FR 49993 , Dec. 4, 1989;  56 FR 24024 , May 28, 
1991;  58 FR 13419 , Mar. 11, 1993;  58 FR 68061 , Dec. 23, 1993;  59 FR 53329 , Oct. 21, 1994;  61 FR 9952 , Mar. 12, 1996;  61 FR 52307 , Oct. 7, 
1996;  62 FR 11105 , Mar. 11, 1997]