5.441A In Brazil, Paraguay and Uruguay, the frequency band 4 800-4 900 MHz, or portions thereof, is identified for the implementation of International Mobile Telecommunications (IMT). This identification does not preclude the use of this frequency band by any application of the services to which it is allocated and does not establish priority in the Radio Regulations. The use of this frequency band for the implementation of IMT is subject to agreement obtained with neighbouring countries, and IMT stations shall not claim protection from stations of other applications of the mobile service. Such use shall be in accordance with Resolution 223 (Rev.WRC 19). (WRC 19)

5.441B In Angola, Armenia, Azerbaijan, Benin, Botswana, Brazil, Burkina Faso, Burundi, Cambodia, Cameroon, China, Côte d’Ivoire, Djibouti, Eswatini, Russian Federation, Gambia, Guinea, Iran (Islamic Republic of), Kazakhstan, Kenya, Lao P.D.R., Lesotho, Liberia, Malawi, Mauritius, Mongolia, Mozambique, Nigeria, Uganda, Uzbekistan, the Dem. Rep. of the Congo, Kyrgyzstan, the Dem. People's Rep. of Korea, Sudan, South Africa, Tanzania, Togo, Viet Nam, Zambia and Zimbabwe, the frequency band 4 800-4 990 MHz, or portions thereof, is identified for use by administrations wishing to implement International Mobile Telecommunications (IMT). This identification does not preclude the use of this frequency band by any application of the services to which it is allocated and does not establish priority in the Radio Regulations. The use of IMT stations is subject to agreement obtained under No. 9.21 with concerned administrations, and IMT stations shall not claim protection from stations of other applications of the mobile service. In addition, before an administration brings into use an IMT station in the mobile service, it shall ensure that the power flux-density (pfd) produced by this station does not exceed −155 dB(W/(m² · 1 MHz)) produced up to 19 km above sea level at 20 km from the coast, defined as the low-water mark, as officially recognized by the coastal State. This pfd criterion is subject to review at WRC 23. Resolution 223 (Rev.WRC 19) applies. This identification shall be effective after WRC 19. (WRC 19)

5.438 Use of the frequency band 4 200-4 400 MHz by the aeronautical radionavigation service is reserved exclusively for radio altimeters installed on board aircraft and for the associated transponders on the ground. (WRC-15)

5.439 Additional allocation: in Iran (Islamic Republic of), the band 4 200-4 400 MHz is also allocated to the fixed service on a secondary basis. (WRC 12)

5.440 The standard frequency and time signal-satellite service may be authorized to use the frequency 4 202 MHz for space-to-Earth transmissions and the frequency 6 427 MHz for Earth-to-space transmissions. Such transmissions shall be confined within the limits of ± 2 MHz of these frequencies, subject to agreement obtained under No. 9.21.

US261 The use of the band 4200-4400 MHz by the aeronautical radionavigation service is reserved exclusively for airborne radio altimeters. Experimental stations will not be authorized to develop equipment for operational use in this band other than equipment related to altimeter stations. However, passive sensing in the Earth-exploration satellite and space research services may be authorized in this band on a secondary basis (no protection is provided from the radio altimeters).

SpectrumWiki

Aeronautical Radio Altimeters

According to the International Civil Aviation Organization (ICAO):

"Th[is] band is used exclusively for airborne radio altimeters (also called radar altimeters) (see Footnote 5.438), which have a vital task in automated landing for flare guidance, and as the sensor component in ground proximity warning systems. The basic function of radio altimeters is to measure the aircraft's absolute height above ground level... These radio altimeters are operational during all phases of flight."

The center frequency for radio altimeters is 4300 +/- 25 MHz. The altimeters use a power output of 20-500 mW, and have a range of up to about 5000 ft (about 1526 m). Their antenna beamwidth is 70 deg, and the pulse width is approximately 200 ns.

Frequency Bands
Band	Use	Service	Table
4200 - 4400 MHz	Radio Altimeters	Aeronautical Radionavigation	-

External Links:

Handbook on Radio Frequency Spectrum Requirements for Civil Aviation (Source: ICAO)

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4 GHz Fixed Service Band

Geostationary Fixed Satellite Service (GSO FSS)

The "C-band" is the workhorse of the Geostationary Fixed Satellite Service (GSO FSS), with 3.7—4.2 GHz the downlink band and its associated uplink 5.925—6.425 GHz. More generally, the 4—8 GHz spectrum is designated as C-band.

Cable TV networks use the C-band to provide programming to cable systems. Program package providers directly serve viewers with home satellite dish receivers (Direct-to-Home FSS or DTH-FSS, a service also available in the Ku-band, see 11.7—12.2 GHz).

Many radio stations receive programming by C-band satellite, and international telephone and data traffic travel over the satellites of the International Telecommunications Satellite Organization (Intelsat) and its competitors in the 4/6 and 11/14 GHz bands.

The C-band also is used for tracking, telemetry, and control (TTC) of satellites while transferring them to final orbit position. Satellite operators want to expand TTC to adjacent spectrum (see 3.65—3.7 GHz).

Paired Frequency Bands
Paired Bands	Use	Service	Table
3700 - 4200 MHz	C-band GSO FSS Downlink	Fixed-satellite	N
5925 - 6425 MHz	C-band GSO FSS Uplink	Fixed-satellite (Earth-to-space)	N

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Common Carrier Fixed Point-to-Point Microwave

These bands are permitted for use by common carrier fixed point-to-point microwave systems under Part 101, Subparts C & I of the FCC rules.

Frequency Bands
Band	Use	Service	Table
2450 - 2500 MHz	Common Carrier Fixed Point-to-Point Microwave	Fixed	N
3700 - 4200 MHz	Common Carrier Fixed Point-to-Point Microwave (max bandwidth 20 MHz)	Fixed	N
5925 - 6425 MHz	Common Carrier Fixed Point-to-Point Microwave (max bandwidth 30 MHz)	Fixed	N
6425 - 6525 MHz	Common Carrier Fixed Point-to-Point Microwave (max bandwidth 25 MHz)	Fixed	N
6525 - 6875 MHz	Common Carrier Fixed Point-to-Point Microwave (max bandwidth 30 MHz)	Fixed	N
10.55 - 10.68 GHz	Common Carrier Fixed Point-to-Point Microwave	Fixed	N
10.7 - 11.7 GHz	Common Carrier Fixed Point-to-Point Microwave (max bandwidth 40 MHz)	Fixed	N
13.2 - 13.25 GHz	Common Carrier Fixed Point-to-Point Microwave (max bandwidth 25 MHz)	Fixed	N
17.7 - 18.58 GHz	Common Carrier Fixed Point-to-Point Microwave (max bandwidth 220 MHz)	Fixed	N
18.58 - 18.82 GHz	Common Carrier Fixed Point-to-Point Microwave (max bandwidth 20 MHz)	Fixed	N
18.82 - 18.92 GHz	Common Carrier Fixed Point-to-Point Microwave (max bandwidth 10 MHz)	Fixed	N
18.92 - 19.16 GHz	Common Carrier Fixed Point-to-Point Microwave (max bandwidth 20 MHz)	Fixed	N
19.16 - 19.26 GHz	Common Carrier Fixed Point-to-Point Microwave (max bandwidth 10 MHz)	Fixed	N
19.26 - 19.7 GHz	Common Carrier Fixed Point-to-Point Microwave (max bandwidth 220 MHz)	Fixed	N
21.2 - 23.6 GHz	Common Carrier Fixed Point-to-Point Microwave (max bandwidth 50 MHz)	Fixed	N

External Links:

FCC NPRM and NOI on Backhaul (FCC 10-146)

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Military Troposcatter Systems

IEEE 802.15.4 HRP UWB

High pulse repetition frequency ultra-wideband (HPR UWB) is one of the physical layers defined for low data rate personal area network (LR-WPAN) communications in the IEEE 802.15.4 standard.

According to the FiRa Consortium:

"In challenging environments, such as parking structures, hospitals, airports and high density venues, ultra-wideband (UWB) technology outperforms other technologies in terms of accuracy, power consumption, robustness in wireless connectivity, and security, by a wide margin.

"UWB securely determines the relative position of peer devices with a very high degree of accuracy and can operate with line of sight at up to 200 meters. In contrast to narrow band wireless technologies, the use of wide bandwidth means UWB provides very stable connectivity, with little to no interference and offers highly precise positioning, even in congested multi-path signal environments.

"By calculating precise location, fine ranging based on UWB is a more secure approach to closing and opening locks, whether those locks are installed on a car door, a warehouse entryway, a conference room, or your front door."

Frequencies
Frequency	Bandwidth	Use	Service	Table
499.2 MHz	499.2 MHz	802.15.4 HRP UWB Channel 0	-	-
3494.4 MHz	499.2 MHz	802.15.4 HRP UWB Channel 1	-	-
3993.6 MHz	499.2 MHz	802.15.4 HRP UWB Channel 2	-	-
3993.6 MHz	1.3312 GHz	802.15.4 HRP UWB Channel 4	-	-
4492.8 MHz	499.2 MHz	802.15.4 HRP UWB Channel 3	-	-
6489.6 MHz	1.0816 GHz	802.15.4 HRP UWB Channel 7	-	-
6489.6 MHz	499.2 MHz	802.15.4 HRP UWB Channel 5	-	-
6988.8 MHz	499.2 MHz	802.15.4 HRP UWB Channel 6	-	-
7488 MHz	499.2 MHz	802.15.4 HRP UWB Channel 8	-	-
7987.2 MHz	1.3312 GHz	802.15.4 HRP UWB Channel 11	-	-
7987.2 MHz	499.2 MHz	802.15.4 HRP UWB Channel 9	-	-
8486.4 MHz	499.2 MHz	802.15.4 HRP UWB Channel 10	-	-
8985.6 MHz	499.2 MHz	802.15.4 HRP UWB Channel 12	-	-
9484.8 MHz	1.35497 GHz	802.15.4 HRP UWB Channel 15	-	-
9484.8 MHz	499.2 MHz	802.15.4 HRP UWB Channel 13	-	-
9984 MHz	499.2 MHz	802.15.4 HRP UWB Channel 14	-	-

External Links:

IEEE 802.15.4 standard (IEEE)

IEEE 802.15.4 (Wikipedia)

Associated Files:

802.15.4 HRP UWB PHY band allocation

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Actions to support FSS Earth stations in 3400-4200 MHz (WRC-15 Agenda Item 9.1.5)

ITU WRC-15 Agenda Item 9.1.5:

"Consideration of technical and regulatory actions in order to support existing and future operation of fixed-satellite service earth stations within the band 3400-4200 MHz, as an aid to the safe operation of aircraft and reliable distribution of meteorological information in some countries in Region 1."

Frequency Bands
Band	Use	Service	Table
3400 - 4200 MHz	Actions to support FSS Earth stations in 3400-4200 MHz (WRC-15 Agenda Item 9.1.5	Fixed-satellite	-

External Links:

ITU-R Preparatory Studies for WRC-15

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WRC-27 study for potential IMT use

WRC-27 agenda item 1.7:

to consider studies on sharing and compatibility and develop technical conditions for the use of International Mobile Telecommunications (IMT) in the frequency bands 4 400-4 800 MHz, 7 125-8 400 MHz (or parts thereof), and 14.8-15.35 GHz taking into account existing primary services operating in these, and adjacent, frequency bands, in accordance with Resolution 256 (WRC-23)

Frequency Bands
Band	Use	Service	Table
4400 - 4800 MHz	WRC-27 study for potential IMT use	Mobile	-
7125 - 8400 MHz	WRC-27 study for potential IMT use	Mobile	-
14.8 - 15.35 GHz	WRC-27 study for potential IMT use	Mobile	-

External Links:

Resolution 256 (WRC-23)

WRC-27 Agenda (see Annex 1)

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WRC-27 consideration of EESS (passive) allocations

WRC-27 agenda item 1.19:

to consider possible primary allocations in all Regions to the Earth exploration-satellite service (passive) in the frequency bands 4 200-4 400 MHz and 8 400-8 500 MHz, in accordance with Resolution 674 (WRC-23)

Frequency Bands
Band	Use	Service	Table
4200 - 4400 MHz	WRC-27 consideration of EESS (passive) allocations	Earth Exploration-satellite	-
8400 - 8500 MHz	WRC-27 consideration of EESS (passive) allocations	Earth Exploration-satellite	-

External Links:

WRC-27 agenda (see annex 1)

Resolution 674 (WRC-23)

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Related Documents, Links, and Multimedia:

FCC Proceeding (3)

Higher Ground LLC Application for Blanket Earth Station License (FCC Order)

With this Order, we grant the application of Higher Ground LLC (Higher Ground), with conditions, for a blanket earth station license to operate up to 50,000 earth stations, known as “SatPaqs,” to communicate with the following U.S.-licensed satellites: Galaxy 3-C at the 95.05° W.L. orbital location, Galaxy 12 at the 129.0º W.L. orbital location, and Galaxy 19 at the 97.0° W.L. orbital location. In doing so, we waive the Table of Frequency Allocations to the extent necessary to permit Higher Ground to provide the services proposed in its application in the 5925-6425 MHz (Earth-to-space) and the 3700-4200 MHz (space-to-Earth) frequency bands on a non-interference basis, subject to the conditions listed below. The authorization will serve the public interest by allowing Higher Ground to provide new communications services to U.S. consumers, with safeguards designed to minimize the risk of harmful interference to primary users operating in these frequency bands. Accordingly, we deny the Petition to Deny filed by the Fixed Wireless Communications Coalition, Inc. (FWCC).

Frequencies/Bands

3700 - 4200 MHz

5925 - 6425 MHz

Document type and status: FCC proceeding (Current)
Document date or date of hyperlink query: March 10, 2017
Fcc Docket(s): SES-LIC-20150616-00357

Higher Ground LLC Application for Blanket Earth Station License (FCC Order)

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FCC Notice of Inquiry on 3980-4200 MHz (Upper C-band)

The 3.7–4.2 GHz band (C-band) is a prime band for many enhanced spectrum-based
services due to its desirable coverage, capacity, and propagation characteristics. In 2020, the Commission
repurposed the 3.7–3.98 GHz portion of the C-band for flexible use in the contiguous United States.
Thanks to those efforts, operators deployed new and improved wireless services that brought 5G to
countless communities, including rural, remote, and underserved areas. To meet projected spectrum
demand, spur economic growth, and advance American security interests, we initiate this proceeding to
consider whether we should take additional actions regarding the remainder of the C-band.

This Notice of Inquiry (NOI) broadly seeks to continue an important and ongoing
conversation among stakeholders about whether the Commission should make some or all of the 3.98–4.2
GHz portion of the band (Upper C-band) available for more intensive use. This NOI is an initial step
towards exploring whether, and if so, how to introduce new operations in the Upper C-band, and we
encourage all interested parties to submit detailed and evidence-based comments to advance current
discussions.

Frequencies/Bands

3980 - 4200 MHz

Document type and status: FCC proceeding (Current)
Document date or date of hyperlink query: May 20, 2025
Fcc Docket(s): GN 25-59

FCC Notice of Inquiry on 3980-4200 MHz (Upper C-band)

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FCC WRC-12 Notice of Proposed Rulemaking (FCC 15-50)

In the Notice of Proposed Rulemaking (WRC-12 Notice), we propose to amend Parts 2, 15, 80, 90, 97, and 101 of the Commission’s rules to implement allocation decisions from the WRC-12 Final Acts and make certain updates to our rules. Specifically, we propose to:

• Allocate the 8.3-11.3 kHz band to the meteorological aids service on a primary basis.

• Allocate the 472-479 kHz band (630 meter band) to the amateur service on a secondary basis.

• Amend the amateur service rules to provide for use of the 135.7-137.8 kHz (2200 meter) and 472-479 kHz (630 meter) bands. Amateur stations would share the band with power line carrier (PLC) systems operated by electric utilities. Amateur stations would be permitted to operate in these bands at fixed locations when separated from electric transmission lines by a specified distance.

• Amend Part 80 of the Commission’s rules to authorize radio buoy operations in the 1900-2000 kHz band under a ship station license.

• Limit the use of the 495-505 kHz band to the maritime mobile service.

• Allocate seven frequency bands (4.438-4.488 MHz, 5.25-5.275 MHz, 16.1-16.2 MHz, 24.45-24.65 MHz, 26.2-26.42 MHz, 41.015-41.665 MHz, and 43.35-44 MHz) to the radiolocation service (RLS) on a primary basis for Federal and non-Federal use, allocate the 13.45-13.55 MHz band to the RLS on a secondary basis for Federal and non-Federal use, limit the use of these RLS allocations to oceanographic radars, require that these radars not cause harmful interference to, or claim protection from, existing and future stations in the incumbent fixed and mobile services, and amend Part 90 of the Commission’s rules accordingly.

• Reallocate the 156.7625-156.7875 MHz (AIS 3) and 156.8125-156.8375 MHz (AIS 4) bands to the MSS (Earth-to-space) on a primary basis for Federal and non-Federal use to allow for greater probability of vessel tracking, with resulting benefits to maritime safety and security.

• Seek comment on the ability of Federal/non-Federal AMT stations to share spectrum with the incumbent services in the 4400-4940 MHz and 5925-6700 MHz bands.

• Extend the AM(R)S allocation from the 5091-5150 MHz band (adopted in the WRC-07 R&O) by also allocating the 5000-5091 MHz range to the AM(R)S on a primary basis for Federal and non-Federal use. AM(R)S use of the smaller 5000-5030 MHz range would extend the tuning range for AeroMACS, with the use of the 5010-5030 MHz band limited to those requirements that cannot be meet in the 5000-5010 MHz and 5091-5150 MHz bands. AM(R)S use of the 5030-5091 MHz band would support line-of-sight control links for unmanned aircraft.

• Allocate the 7850-7900 MHz band to the meteorological-satellite service (space-to-Earth) on a primary basis for Federal use.

• Allocate the 15.4-15.7 GHz band to the RLS on a primary basis for Federal use.

• Allocate the 22.55-23.15 GHz band to the space research service (SRS) (Earth-to-space) on a primary basis for Federal and non-Federal use and allocate the 25.5-27 GHz band to the SRS (space-to-Earth) on a primary basis for non-Federal use.

• Delete the aeronautical mobile service allocation from the 37-38 GHz band.

• Encourage operators of fixed stations operating in the 81-86 GHz and 92-94 GHz bands to take all reasonable steps to ensure that their unwanted emissions power in the 86-92 GHz band does not exceed the levels recommended by WRC-12.

Frequencies/Bands

8.3 - 11.3 kHz

135.7 - 137.8 kHz

472 - 479 kHz

495 - 505 kHz

1900 - 2000 kHz

4438 - 4488 kHz

5250 - 5275 kHz

13450 - 13550 kHz

16100 - 16200 kHz

24450 - 24650 kHz

26200 - 26420 kHz

41.015 - 41.665 MHz

43.35 - 44 MHz

156.775 MHz

156.825 MHz

4400 - 4940 MHz

5000 - 5150 MHz

5925 - 6700 MHz

7850 - 7900 MHz

15.4 - 15.7 GHz

22.55 - 23.15 GHz

25.5 - 27 GHz

37 - 38 GHz

86 - 92 GHz

275 - 3000 GHz

Document type and status: FCC proceeding (Current)
Document date or date of hyperlink query: July 29, 2015

FCC WRC-12 Notice of Proposed Rulemaking (FCC 15-50)

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Engineering Data

	Lower Frequency	Center Frequency	Upper Frequency
Frequency	4.2 GHz	4.3 GHz	4.4 GHz
Wavelength	7.1 cm	7.0 cm	6.8 cm
Band designator(s)	SHF; C-band (IEEE)	SHF; C-band (IEEE)	SHF; C-band (IEEE)
Isotropic collecting area	4.1 cm²	3.9 cm²	3.7 cm²
Free space loss (1 m)	44.9 dB	45.1 dB	45.3 dB
Free space loss (1 km)	104.9 dB	105.1 dB	105.3 dB
Free space loss (10 km)	124.9 dB	125.1 dB	125.3 dB
Free space loss (100 km)	144.9 dB	145.1 dB	145.3 dB
Free space loss (1000 km)	164.9 dB	165.1 dB	165.3 dB
Free space loss (35,786 km = GEO orbit)	196.0 dB	196.2 dB	196.4 dB
Free space loss (378,370 km = Moon)	216.5 dB	216.7 dB	216.9 dB