CFR > Title 47 - Telecommunication > CHAPTER I—FEDERAL COMMUNICATIONS COMMISSION > SUBCHAPTER B—COMMON CARRIER SERVICES (Parts 20–69) > PART 25—SATELLITE COMMUNICATIONS > SUBPART C—Technical Standards (§25.201 to §25.263) > 25.208—Power flux density limits.

25.208—Power flux density limits.

(a) In the band 3650-4200 MHz, the power flux density at the Earth's surface produced by emissions from a space station for all conditions and for all methods of modulation shall not exceed the following values:
−152 dB(W/m2) in any 4 kHz band for angles of arrival between 0 and 5 degrees above the horizontal plane;
−152 (δ−5)/2 dB(W/m2) in any 4 kHz band for angles of arrival δ (in degrees) between 5 and 25 degrees above the horizontal plane; and
−142 dB(W/m2) in any 4 kHz band for angles of arrival between 25 and 90 degrees above the horizontal plane
These limits relate to the power flux density which would be obtained under assumed free-space propagation conditions.
(b) In the bands 10.95-11.2 and 11.45-11.7 GHz for GSO FSS space stations and 10.7-11.7 GHz for NGSO FSS space stations, the power flux-density at the Earth's surface produced by emissions from a space station for all conditions and for all methods of modulation shall not exceed the lower of the following values:
(1) −150 dB(W/m 2) in any 4 kHz band for angles of arrival between 0 and 5 degrees above the horizontal plane; −150 (δ−5)/2 dB(W/m 2) in any 4 kHz band for angles of arrival (δ) (in degrees) between 5 and 25 degrees above the horizontal plane; and −140 dB(W/m 2) in any 4 kHz band for angles of arrival between 25 and 90 degrees above the horizontal plane; or
(2) −126 dB(W/m 2) in any 1 MHz band for angles of arrival between 0 and 5 degrees above the horizontal plane; −126 (δ−5)/2 dB(W/m 2) in any 1 MHz band for angles of arrival (δ) (in degrees) between 5 and 25 degrees above the horizontal plane; and −116 dB(W/m 2) in any 1 MHz band for angles of arrival between 25 and 90 degrees above the horizontal plane.

Code of Federal Regulations

Code of Federal Regulations 230
Note to paragraph (b): These limits relate to the power flux density, which would be obtained under assumed free-space propagation conditions.
(c) In the 17.7-17.8 GHz, 18.3-18.8 GHz, 19.3-19.7 GHz, 22.55-23.00 GHz, 23.00-23.55 GHz, and 24.45-24.75 GHz frequency bands, the power flux density at the Earth's surface produced by emissions from a space station for all conditions for all methods of modulation shall not exceed the following values:
(1) −115 dB (W/m 2) in any 1 MHz band for angles of arrival between 0 and 5 degrees above the horizontal plane.
(2) −115 0.5 (δ-5) dB (W/m 2) in any 1 MHz band for angles of arrival d (in degrees) between 5 and 25 degrees above the horizontal plane.
(3) −105 dB (W/m 2) in any 1 MHz band for angles of arrival between 25 and 90 degrees above the horizontal plane.
(d) In addition to the limits specified in paragraph (c) of this section, the power flux-density across the 200 MHz band 18.6-18.8 GHz produced at the Earth's surface by emissions from a space station under assumed free-space propagation conditions shall not exceed −95 dB (W/m 2) for all angles of arrival. This limit may be exceeded by up to 3 dB for no more than 5% of the time.
(e) In the 18.8-19.3 GHz frequency band, the power flux-density at the Earth's surface produced by emissions from a space station for all conditions and for all methods of modulation shall not exceed the following values:
−115−X dB(W/m2÷MHz) for 0° ≤ δ < 5°
−115−X ((10 X)/20)(δ−5)dB(W/m2÷MHz) for 5° ≤ δ < 25°
−105 dB(W/m2÷MHz) for 25° ≤ δ < 90°
Where:
δ: is the angle of arrival above the horizontal plane; and
X is defined as a function of the number of satellites in the non-GSO FSS constellation, n, as follows:
for n ≤ 50 X = 0 (dB)
for 50 < n ≤ 288 X = (5/119) (n − 50) (dB)
for n > 288 X = (1/69) (n 402) (dB)
(f) [Reserved]
(g) In the frequency bands 10.7-11.7 GHz and 11.7-12.2 GHz, the single-entry equivalent power-flux density in the space-to-Earth direction (EPFDdown ), at any point on the Earth's surface, produced by emissions from all co-frequency space stations of a single non-geostationary-satellite orbit (NGSO) system operating in the fixed-satellite service (FSS) shall not exceed the following limits for the given percentages of time. Tables 1G and 2G follow:
Table 1G—Single-Entry EPFDdown Limits for Protection of 0.6, 1.2, 3 and 10 Meter GSO FSS Earth Station Antennas 1,2
Frequency band (GHz) for InternationalAllocations Single-entry EPFDdown dB(W/m2) Percentage of time during which EPFDdown level may not be exceeded Reference bandwidth (kHz) Reference antenna diameter and reference radiation pattern 3
10.7-11.7 in all Regions; 11.7-12.2 in Region 2; 12.2-12.5 in Region 3; and 12.5-12.75 in Regions 1 and 3 −175.4−174 −170.8 −165.3 −160.4 −160 −160 090 99 99.73 99.991 99.997 100 40 60 cm, Recommendation ITU-R S.1428.
10.7-11.7 in all Regions; 11.7-12.2 in Region 2; 12.2-12.5 in Region 3; and 12.5-12.75 in Regions 1 and 3 −181.9−178.4 −173.4 −173 −164 −161.6 −161.4 −160.8 −160.5 −160 −160 099.5 99.74 99.857 99.954 99.984 99.991 99.997 99.997 99.9993 100 40 1.2 m, Recommendation ITU-R S.1428.
Code of Federal Regulations 231
10.7-11.7 in all Regions; 11.7-12.2 in Region 2; 12.2-12.5 in Region 3; and 12.5-12.75 in Regions 1 and 3 −190.45−189.45 −187.45 −182.4 −182 −168 −164 −162 −160 −160 090 99.5 99.7 99.855 99.971 99.988 99.995 99.999 100 40 3 m, Recommendation ITU-R S.1428.
10.7-11.7 in all Regions; 11.7-12.2 in Region 2; 12.2-12.5 in Region 3; and 12.5-12.75 in Regions 1 and 3 −195.45−195.45 −190 −190 −172.5 −160 −160 099 99.65 99.71 99.99 99.998 100 40 10 m, Recommendation ITU-R S.1428.
1 In addition to the limits shown in Table 1G, the limits shown in Table 2G shall apply to all antenna sizes greater than 60 cm in the frequency bands listed in Table 1G.
2 For each reference antenna diameter, the limit consists of the complete curve on a plot which is linear in decibels for the EPFD levels and logarithmic for the time percentages, with straight lines joining the data points.
3 The earth station antenna reference radiation patterns are to be used only for the calculation of interference from NGSO FSS systems into GSO FSS systems.
Table 2G—Single-Entry EPFDdown Limits Radiated By Non-GSO FSS Systems At Certain Latitudes
100% of the time EPFDdown dB(W/(m2/40 kHz)) Latitude (North or South in degrees)
-160 0 < | Latitude | ≤ 57.5.
-160 3.4 (57.5 − | Latitude | )/4 57.5 < | Latitude | ≤ 63.75
-165.3 63.75 ≤ | Latitude |

Code of Federal Regulations

Note to paragraph (g): These limits relate to the equivalent power flux density, which would be obtained under free-space propagation conditions, for all conditions and for all methods of modulation.
(h) In the frequency bands 10.7-11.7 GHz and 11.7-12.2 GHz, the aggregate equivalent power-flux density in the space-to-Earth direction (EPFDdown ), at any point on the Earth's surface, produced by emissions from all co-frequency space stations of all non-geostationary-satellite orbit systems operating in the fixed-satellite service (FSS) shall not exceed the following limits for the given percentages of time. Tables 1H and 2H follow:
Table 1H—Aggregate EPFDdown Limits for Protection of 0.6, 1.2, 3 and 10 Meter GSO FSS Earth Station Antennas 1
Frequency band (GHz) for International Allocations Aggregate EPFDdown dB(W/m2) Percentage of time during which EPFDdown may not beexceeded Reference bandwidth (kHz) Reference antenna diameter and reference radiation pattern 2
10.7-11.7 in all Regions; 11.7-12.2 in Region 2; 12.2-12.5 in Region 3; and 12.5-12.75 in Regions 1 and 3 −170−168.6 −165.3 −160.4 −160 −160 090 99 99.97 99.99 100 40 60 cm, Recommendation ITU-R S.1428.
10.7-11.7 in all Regions; 11.7-12.2 in Region 2; 12.2-12.5 in Region 3; and 12.5-12.75 in Regions 1 and 3 −176.5−173 −164 −161.6 −164.4 −160.8 −160.5 −160 −160 099.5 99.84 99.945 99.97 99.99 99.99 99.9975 100 40 1.2 m, Recommendation ITU-R S.1428.
10.7-11.7 in all Regions; 11.7-12.2 in Region 2; 12.2-12.5 in Region 3; and 12.5-12.75 in Regions 1 and 3 −185−184 −182 −168 −164 −162 −160 −160 090 99.5 99.9 99.96 99.982 99.997 100 40 3 m, Recommendation ITU-R S.1428.
10.7-11.7 in all Regions; 11.7-12.2 in Region 2; 12.2-12.5 in Region 3; and 12.5-12.75 in Regions 1 and 3 −190−190 −166 −160 −160 099 99.99 99.998 100 40 10 m, Recommendation ITU-R S.1428.
1 In addition to the limits shown in Table 1H, the aggregate EPFDdown limits shown in Table 2H shall apply to all antenna sizes greater than 60 cm in the frequency bands listed in Table 1H.
2 The earth station antenna reference patterns are to be used only for the calculation of interference from NGSO FSS systems into GSO FSS systems.
Table 2H—Single-Entry EPFDdown Limits Radiated By Non-GSO FSS Systems At Certain Latitudes
100% of the time EPFDdown dB(W/(m2/40 kHz)) Latitude (North or South in degrees)
-160 0 < | Latitude | ≤ 57.5
-160 3.4 (57.5 − | Latitude |)/4 57.5 < | Latitude | ≤ 63.75
-165.3 63.75 ≤ | Latitude |

Code of Federal Regulations

Note to paragraph (h): These limits relate to the equivalent power flux density, which would be obtained under free-space propagation conditions, for all conditions and for all methods of modulation.
(i) In the frequency bands 10.7-11.7 GHz and 11.7-12.2 GHz, the additional operational equivalent power-flux density, in the space-to-Earth direction, (additional operational EPFDdown) at any point on the Earth's surface, produced by actual operational emissions from all co-frequency space stations of a non-geostationary-satellite orbit (NGSO) system operating in the fixed-satellite service (FSS) shall not exceed the following operational limits for the given percentages of time:
Additional Operational Limits on the EPFDdown Radiated by Non-GSO FSS Systems Into 3 m and 10 m GSO FSS Earth Station Antennas
EPFDdown dB(W/(m2/40 kHz)) Percentage of time during which EPFDdown may not be exceeded Receive GSO earth stationantenna diameter (m)
−182 99.9
−179 99.94
−176 99.97
−171 99.98
−168 99.984 3
−165 99.993
−163 99.999
−161.25 99.99975
−161.25 100
−185 99.97
−183 99.98
−179 99.99
−175 99.996
−171 99.998 10
−168 99.999
−166 99.9998
−166 100

Code of Federal Regulations

Note to paragraph (i): These limits relate to the equivalent power flux density, which is obtained under free-space propagation conditions, for all conditions and for all methods of modulation.
(j) In the frequency bands 10.7-11.7 GHz and 11.7-12.2 GHz, the operational equivalent power-flux density, in the space-to-Earth direction, (operational EPFDdown) at any point on the Earth's surface, produced by actual operational emissions from the in-line co-frequency space station of a non-geostationary-satellite orbit (NGSO) system operating in the fixed-satellite service (FSS) shall not exceed the following operational limits for 100% of the time:
Operational Limits to the EPFDdown Radiated by Non-GSO FSS Systems in Certain Frequency Bands1
Frequency band (GHz) for International allocations EPFDdown dB(W/m2) Percentage of time during which EPFDdown may not be exceeded Reference bandwidth (kHz) Receive GSO earth station antenna diameter 2 (m) Orbital inclination of GSO satelite (degrees)
Prior to 31 December 2005: 10.7-11.7 in all Regions; 11.7-12.2 in Regions 2; 12.2-12.5 in Region 3; and 12.5;-12.75 in Regions 1 and 3 −163−166 −167.5 −169.5 100 40 36 9 ≥18 ≤2.5
Prior to 31 December 2005: 10.7-11.7 in all Regions; 11.7-12.2 in Region 2; 12.2-12.5 in Region 3; and 12.5-12.75 in Regions 1 and 3 −160−163 −164.5 −166.5 100 40 36 9 ≥18 >2.5 and ≤4.5
From 31 December 2005: 10.7-11.7 in all Regions; 11.7-12.2 in Region 2; 12.2-12.5 in Region 3; and 12.5-12.75 in Regions 1 and 3 −161.25−164 −165.5 −167.5 100 40 36 9 ≥18 ≤2.5
Code of Federal Regulations 234
From 31 December 2005: 10.7-11.7 in all Regions; 11.7-12.2 in Region 2; 12.2-12.5 in Region 3; and 12.5-12.75 in Regions 1 and 3 −158.25−161 −162.5 −164.5 100 40 36 9 ≥18 >2.5 and ≤4.5
1 The operational limits on the EPFDdown radiated by non-GSO FSS systems shall be the values given in Table 2G or this table, whichever are the more stringent.
2 For antenna diameters between the values given in this table, the limits are given by linear interpolation using a linear scale for EPFDdown in decibels and a logarithmic scale for antenna diameter in meters.

Code of Federal Regulations

Note to paragraph (j): These limits relate to the operational equivalent power flux-density which would be obtained under free-space propagation conditions, for all conditions, for all methods of modulation and for the specified inclined GSO FSS operations.
(k) In the frequency bands 12.75-13.15 GHz, 13.2125-13.25 GHz and 13.75-14.5 GHz, the equivalent power flux-density, in the Earth-to-space direction, (EPFDup) produced at any point on the geostationary satellite orbit (GSO) by the emissions from all co-frequency earth stations in a non-geostationary satellite orbit fixed-satellite service (NGSO FSS) system, for all conditions and for all methods of modulation, shall not exceed the following limits for the specified percentages of time limits:
Limits to the EPFDup Radiated by NGSO FSS Systems in Certain Frequency Bands
Frequency band (GHz) for International Allocations EPFDup dB(W/m2) Percentage of time during which EPFDup may not be exceeded Reference bandwidth (kHz) Reference antenna beamwidth and reference radiation pattern 1
12.5-12.75; 12.75-13.25; 13.75-14.5 −160 100 40 4°ITU-R S.672-4, Ls=−20
1 For the case of Ls = −10, the values a = 1.83 and b = 6.32 should be used in the equations in the Annex of Recommendation ITU-R S.672-4 for single-feed circular beams. In all cases of Ls, the parabolic main beam equation should start at zero.

Code of Federal Regulations

Note to paragraph (k): These limits relate to the uplink equivalent power flux density, which would be obtained under free-space propagation conditions, for all conditions and for all methods of modulation.
(l) In the frequency bands 11.7-12.2 GHz and 12.5-12.75 GHz in Region 3, 11.7-12.5 GHz in Region 1 and 12.2-12.7 GHz in Region 2, the single-entry equivalent power-flux density, in the space-to-Earth direction, (EPFDdown ), at any point on the Earth's surface, produced by emissions from all co-frequency space stations of a single non-geostationary-satellite orbit (NGSO) system operating in the fixed-satellite service (FSS) shall not exceed the following limits in Tables 1L and 2L for the given percentages of time:
Table 1L—Single-Entry EPFD Down Limits for Protection of 30, 45, 60, 90, 120, 180, 240 and 300 CM GSO BSS Earth Station Antennas 1,2,3,5
Frequency band (GHz) for internationalallocations EPDF down dB(W/m2) Percentage of time during which EPFDdown level may not be exceeded Reference bandwidth (kHz) Reference antenna diameter and reference radiation pattern 4
11.7-12.5 in Region 1; 1.7-12.2 and 12.5-12.75 in Region 3; 12.2-12.7 in Region 2 −165.841−165.541 −164.041 −158.6 −158.6 −158.33 −158.33 025 96 98.857 99.429 99.429 99.429 100 40 30 cmRecommendation ITU-R BO.1443 Annex 1
11.7-12.5 in Region 1; 1.7-12.2 and 12.5-12.75 in Region 3; 12.2-12.7 in Region 2 −175.441−172.441 −169.441 −164 −160.75 −160 −160 066 97.75 99.357 99.809 99.986 100 40 45 cmRecommendation ITU-R BO.1443 Annex 1
11.7-12.5 in Region 1; 1.7-12.2 and 12.5-12.75 in Region 3; 12.2-12.7 in Region 2 −176.441−173.191 −167.75 −162 −161 −160.2 −160 −160 097.8 99.371 99.886 99.943 99.971 99.997 100 40 60 cmRecommendation ITU-R BO. 1443 Annex 1
11.7-12.5 in Region 1; 1.7-12.2 and 12.5-12.75 in Region 3; 12.2-12.7 in Region 2 −178.94−178.44 −176.44 −171 −165.5 −163 −161 −160 −160 033 98 99.429 99.714 99.857 99.943 99.991 100 40 90 cmRecommendation ITU-R BO.1443 Annex 1
11.7-12.5 in Region 1; 1.7-12.2 and 12.5-12.75 in Region 3; 12.2-12.7 in Region 2 −182.44−180.69 −179.19 −178.44 −174.94 −173.75 −173 −169.5 −167.8 −164 −161.9 −161 −160.4 −160 090 98.9 98.9 99.5 99.68 99.68 99.85 99.915 99.94 99.97 99.99 99.998 100 40 120 cmRecommendation ITU-R BO.1443 Annex 1
11.7-12.5 in Region 1; 1.7-12.2 and 12.5-12.75 in Region 3; 12.2-12.7 in Region 2 −184.941−184.101 −181.691 −176.25 −163.25 −161.5 −160.35 −160 −160 033 98.5 99.571 99.946 99.974 99.993 99.999 100 40 180 cm 3 Recommendation ITU-R BO.1443 Annex 1
11.7-12.5 in Region 1; 1.7-12.2 and 12.5-12.75 in Region 3; 12.2-12.7 in Region 2 −187.441−186.341 −183.441 −178 −161.4 −161.9 −160.5 −160 −160 033 99.25 99.786 99.957 99.983 99.994 99.999 100 40 240 cm 2 Recommendation ITU-R BO.1443 Annex 1
Code of Federal Regulations 236
11.7-12.5 in Region 1; 1.7-12.2 and 12.5-12.75 in Region 3; 12.2-12.7 in Region 2 −191.941−189.441 −185.941 −180.5 −173 −167 −162 −160 −160 033 99.5 99.857 99.914 99.951 99.983 99.991 100 40 300 cmRecommendation ITU-R BO.1443 Annex 1
1 For BSS antenna diameters 180 cm, 240 cm and 300 cm, in addition to the single-entry limits shown in Table 1L, the limits in Table 2L shall also apply in the frequency band listed in Table 1L.
2 For 240 cm GSO BSS earth station antennas located in Alaska, communicating with GSO BSS satellites at the 91° W.L., 101° W.L., 110° W.L., 119° W.L. and 148° W.L. nominal orbital locations with elevation angles greater than 5°, −167 dB(W/(m2/40 kHz)) single-entry 100% of the time operational EPFDdown limit also applies to receive antennas.
3 For 180 cm GSO BSS earth station antennas located in Hawaii communicating with GSO BSS satellites that are operational as of December 30, 1999 at the 110° W.L., 119° W.L. and 148° W.L. nominal orbital positions, −162.5 dB(W/(m2/40 kHz)) single-entry 100% of the time operational EPFDdown limit also applies.
4 Under the section reference pattern of Annex 1 to Recommendation ITU-R BO.1443 shall be used only for the calculation of interference from non-GSO FSS systems into BSS systems.
5 For each reference antenna diameter, the limit consists of the complete curve on a plot which is linear in decibels for the EPFD levels and logarithmic for the time percentages, with straight line joining the data points.
Table 2L—Single-Entry EPFDdown Limits Radiated By Non-GSO FSS Systems At Certain Latitudes
100% of the time EPFDdown dB(W/(m2/40 kHz)) Latitude (North or South in degrees)
−160.0 0 ≤ | Latitude | ≤ 57.5
−160.0 3.4 (57.5 − | Latitude |)/4 57.5 ≤ | Latitude | ≤ 63.75
−165.3 63.75 ≤ | Latitude |

Code of Federal Regulations

Note to paragraph (l): These limits relate to the equivalent power flux density, which would be obtained under free-space propagation conditions, for all conditions and for all methods of modulation.
(m) In the frequency bands 11.7-12.2 GHz and 12.5-12.75 GHz in Region 3, 11.7-12.5 GHz in Region 1 and 12.2-12.7 GHz in Region 2, the aggregate equivalent power-flux density, in the space-to-Earth direction, (EPFDdown) at any point on the Earth's surface, produced by emissions from all co-frequency space stations of all non-geostationary-satellite orbit systems operating in the fixed-satellite service (FSS) shall not exceed the following limits in Tables 1M and 2M for the given percentages of time:
Table 1M—Aggregate EPFDdown Limits for Protection of 30, 45, 60, 90, 120, 180, 240 and 300 cm GSO BSS Earth Station Antennas 1,2,3,5 Contact Us | About Us | Terms | Privacy

Frequency band (GHz) for international allocations EPFDdown dB (W/m2) Percentage of time during which EPFDdown level may not be exceeded Reference bandwidth (kHz) Reference antenna diameter, and reference radiation pattern 4
11.7-12.5 in Region 1; 11.7-12.2 and 12.5-12.75 in Region 3; 12.2-12.7 in Region 2 −160.4−160.1 −158.6 −158.6 −158.33 −158.33 025 96 98 98 100 40 30 cmRecommendation ITU-R BO.1443 Annex 1.
11.7-12.5 in Region 1; 11.7-12.2 and 12.5-12.75 in Region 3; 12.2-12.7 in Region 2 −170−167 −164 −160.75 −160 −160 066 97.75 99.33 99.95 100 40 45 cmRecommendation ITU-R BO.1443 Annex 1.
11.7-12.5 in Region 1; 11.7-12.2 and 12.5-12.75 in Region 3; 12.2-12.7 in Region 2 −171−168.75 −167.75 −162 −161 −160.2 −160 −160 090 97.8 99.6 99.8 99.9 99.99 100 40 60 cmRecommendation ITU-R BO.1443 Annex 1.
11.7-12.5 in Region 1; 11.7-12.2 and 12.5-12.75 in Region 3; 12.2-12.7 in Region 2 −173.75−173 −171 −165.5 −163 −161 −160 −160 033 98 99.1 99.5 99.8 99.97 100 40 90 cmRecommendation ITU-R BO.1443 Annex 1.
11.7-12.5 in Region 1; 11.7-12.2 and 12.5-12.75 in Region 3; 12.2-12.7 in Region 2 −177−175.25 −173.75 −173 −169.5 −167.8 −164 −161.9 −161 −160.4 −160 090 98.9 98.9 99.5 99.7 99.82 99.9 99.965 99.993 100 40 120 cmRecommendation ITU-R BO.1443 Annex 1.