Allocations

 
U.S. Non-Federal-Government Allocations
121.9375 - 123.0875 MHz
AERONAUTICAL MOBILE

FCC Rule Parts:
Aviation (87)

U.S. Federal Government Allocations
121.9375 - 123.0875 MHz


ITU Region 1 Allocations
117.975 - 137 MHz
AERONAUTICAL MOBILE (R)


ITU Region 2 Allocations
117.975 - 137 MHz
AERONAUTICAL MOBILE (R)


ITU Region 3 Allocations
117.975 - 137 MHz
AERONAUTICAL MOBILE (R)


SpectrumWiki

Band Uses (117.975 - 137 MHz)


Footnotes

5.111   The carrier frequencies 2 182 kHz, 3 023 kHz, 5 680 kHz, 8 364 kHz and the frequencies 121.5 MHz, 156.525 MHz, 156.8 MHz and 243 MHz may also be used, in accordance with the procedures in force for terrestrial radiocommunication services, for search and rescue operations concerning manned space vehicles. The conditions for the use of the frequencies are prescribed in Article 31.
    The same applies to the frequencies 10 003 kHz, 14 993 kHz and 19 993 kHz, but in each of these cases emissions must be confined in a band of ± 3 kHz about the frequency. (WRC 07)

5.200   In the band 117.975-137 MHz, the frequency 121.5 MHz is the aeronautical emergency frequency and, where required, the frequency 123.1 MHz is the aeronautical frequency auxiliary to 121.5 MHz. Mobile stations of the maritime mobile service may communicate on these frequencies under the conditions laid down in Article 31 for distress and safety purposes with stations of the aeronautical mobile service. (WRC 07)

5.201   Additional allocation: in Armenia, Azerbaijan, Belarus, Bulgaria, Estonia, the Russian Federation, Georgia, Hungary, Iran (Islamic Republic of), Iraq (Republic of), Japan, Kazakhstan, Mali, Mongolia, Mozambique, Uzbekistan, Papua New Guinea, Poland, Kyrgyzstan, Romania, Senegal, Tajikistan, Turkmenistan and Ukraine, the frequency band 132-136 MHz is also allocated to the aeronautical mobile (OR) service on a primary basis. In assigning frequencies to stations of the aeronautical mobile (OR) service, the administration shall take account of the frequencies assigned to stations in the aeronautical mobile (R) service. (WRC 19)

5.202   Additional allocation: in Saudi Arabia, Armenia, Azerbaijan, Bahrain, Belarus, Bulgaria, the United Arab Emirates, the Russian Federation, Georgia, Iran (Islamic Republic of), Jordan, Mali, Oman, Uzbekistan, Poland, the Syrian Arab Republic, Kyrgyzstan, Romania, Senegal, Tajikistan, Turkmenistan and Ukraine, the frequency band 136-137 MHz is also allocated to the aeronautical mobile (OR) service on a primary basis. In assigning frequencies to stations of the aeronautical mobile (OR) service, the administration shall take account of the frequencies assigned to stations in the aeronautical mobile (R) service. (WRC 19)

US30   The band 121.9375-123.0875 MHz is available to FAA aircraft for communications pursuant to flight inspection functions in accordance with the Federal Aviation Act of 1958.

US31   The frequencies 122.700, 122.725, 122.750, 122.800, 122.950, 122.975, 123.000, 123.050 and 123.075 MHz may be assigned to aeronautical advisory stations. In addition, at landing areas having a part-time or no airdrome control tower or FAA flight service station, these frequencies may be assigned on a secondary non-interference basis to aeronautical utility mobile stations, and may be used by FAA ground vehicles for safety related communications during inspections conducted at such landing areas.

    The frequencies 122.850, 122.900 and 122.925 MHz may be assigned to aeronautical multicom stations. In addition, 122.850 MHz may be assigned on a secondary noninterference basis to aeronautical utility mobile stations. In case of 122.925 MHz, US213 applies.

    Air carrier aircraft stations may use 122.000 and 122.050 MHz for communication with aeronautical stations of the Federal Aviation Administration and 122.700, 122.800, 122.900 and 123.000 MHz for communications with aeronautical stations pertaining to safety of flight with and in the vicinity of landing areas not served by a control tower.

    Frequencies in the band 121.9375-122.6875 MHz may be used by aeronautical stations of the Federal Aviation Administration for communication with aircraft stations.

US33   The band 123.1125-123.5875 MHz is for use by flight test and aviation instructional stations. The frequency 121.950 MHz is available for aviation instructional stations.

US80   Federal stations may use the frequency 122.9 MHz subject to the following conditions: (a) All operations by Federal stations shall be restricted to the purpose for which the frequency is authorized to non-Federal stations, and shall be in accordance with the appropriate provisions of the Commission’s Rules and Regulations, Part 87, Aviation Services; (b) Use of the frequency is required for coordination of activities with Commission licensees operating on this frequency; and (c) Federal stations will not be authorized for operation at fixed locations.

US102   In Alaska only, the frequency 122.1 MHz may also be used for air carrier air traffic control purposes at locations where other frequencies are not available to air carrier aircraft stations for air traffic control.

US213   The frequency 122.925 MHz is for use only for communications with or between aircraft when coordinating natural resources programs of Federal or State natural resources, agencies, including forestry management and fire suppression, fish and game management and protection and environmental monitoring and protection.


SpectrumWiki

 
Orbcomm LEO Satellite Constellation
WRC-23 Agenda Item 1.7 Spectrum for Space-Based VHF Aeronautical Communications




Related Documents, Links, and Multimedia:
Occupancy Measurements (10)




Engineering Data

Lower Frequency Center Frequency Upper Frequency
Frequency 117.975 MHz 127.4875 MHz 137 MHz
Wavelength 2.5 m 2.4 m 2.2 m
Band designator(s) VHF VHF VHF
Isotropic collecting area 5,138.7 cm2 4,400.4 cm2 3,810.6 cm2
Free space loss (1 m) 13.9 dB 14.6 dB 15.2 dB
Free space loss (1 km) 73.9 dB 74.6 dB 75.2 dB
Free space loss (10 km) 93.9 dB 94.6 dB 95.2 dB
Free space loss (100 km) 113.9 dB 114.6 dB 115.2 dB
Free space loss (1000 km) 133.9 dB 134.6 dB 135.2 dB
Free space loss
(35,786 km = GEO orbit)
165.0 dB 165.6 dB 166.3 dB
Free space loss (378,370 km = Moon) 185.4 dB 186.1 dB 186.7 dB
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