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)

5.252 Alternative allocation: in Botswana, Eswatini, Lesotho, Malawi, Mozambique, Namibia, South Africa, Zambia and Zimbabwe, the frequency bands 230-238 MHz and 246-254 MHz are allocated to the broadcasting service on a primary basis, subject to agreement obtained under No. 9.21. (WRC 19)

5.254 The bands 235-322 MHz and 335.4-399.9 MHz may be used by the mobile-satellite service, subject to agreement obtained under No. 9.21, on condition that stations in this service do not cause harmful interference to those of other services operating or planned to be operated in accordance with the Table of Frequency Allocations except for the additional allocation made in footnote No. 5.256A. (WRC-03)

5.256 The frequency 243 MHz is the frequency in this band for use by survival craft stations and equipment used for survival purposes. (WRC 07)

5.256A Additional allocation: in China, the Russian Federation and Kazakhstan, the frequency band 258-261 MHz is also allocated to the space research service (Earth-to-space) and space operation service (Earth-to-space) on a primary basis. Stations in the space research service (Earth-to-space) and space operation service (Earth-to-space) shall not cause harmful interference to, or claim protection from, or constrain the use and development of, the mobile service systems and mobile-satellite service systems operating in the frequency band. Stations in space research service (Earth-to-space) and space operation service (Earth-to-space) shall not constrain the future development of fixed service systems of other countries. (WRC-15)

G27 In the bands 225-328.6 MHz, 335.4-399.9 MHz, and 1350-1390 MHz, the fixed and mobile services are limited to the military services.

G100 The bands 235-322 MHz and 335.4-399.9 MHz are also allocated on a primary basis to the mobile-satellite service, limited to military operations.

SpectrumWiki

Band Uses (235 - 267 MHz)

UHF Follow-On (UFO) Satellite Constellation

UFO is a narrowband satellite communications system belonging to the U.S. military. The first UFO satellite was launched in September 1993, and the tenth was launched in December 2003. Presently eight of the satellites remain functional, and the constellation is passing its expected lifetime. MUOS (see separate wiki entry) is the UFO replacement. All UFO satellites are in geostationary orbit. Each satellite provides 21 5-kHz channels and 17 25-kHz channels.

Frequency Bands
Band	Use	Service	Table
243 - 270 MHz	UFO service downlink	Mobile-satellite	F
292 - 317 MHz	UFO service uplink	Mobile-satellite	F

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Military Mobile-Satellite Communications (NTIA)

Satellites operating in the mobile-satellite service in this band are used by the military services and the Coast Guard. The military mobile-satellite communications networks in the band serve ships at sea, aircraft, land-based forces, and a variety of other U.S. military fixed and mobile terminals used by mobile users. The bands 225-322 MHz and 335.4- 399.9 MHz are the only bands below 7250 MHz available for Federal Government mobile-satellite communications, and the narrowband satellite links are frequently the only reliable means of communications.

The military makes extensive use of the mobile-satellite service operating in this band because the electromagnetic waves can penetrate foliage, inclement weather, and urban terrain including concrete-reinforced buildings. Small antennas can be used at the earth terminals making it easy to transport the stations. There are numerous satellite earth terminals currently in use by the military, many of which are small and portable enough to be carried deep into theaters of operation.

The Federal use of the band for mobile satellites was initiated in 1978 with the Navy's Fleet Satellite Communications System (FLTSATCOM), a constellation of five geostationary satellites operating in the band 235-322 MHz, channelized into the downlinks at 243.855-269.95 MHz and corresponding uplinks in the band 292.85- 317.325 MHz. The Navy began upgrading the FLTSATCOM in the 1990s with the UHF Follow-On (UFO) satellites. The UFO satellites offer increased communications channel capacity over the same frequency spectrum used by the previous FLTSATCOM systems. Each UFO satellite has 39 channels with a total 555 kHz bandwidth. The satellite payload comprises 21 narrowband channels at 5 kHz each and 17 relay channels at 25 kHz.3 These channels are used by the military agencies for tactical communications on land, ships, submarines, and aircraft. The Coast Guard also uses channels on the military satellites on some of their ships.

The Department of Defense (DOD) Defense Satellite Communications System (DSCS-III) series of geostationary satellites operating in the 7- and 8- GHz bands also carry a transponder in this band called the single channel transponder (SCT) that provides communications for emergency action messages to the forces. The Military, Strategic, and Tactical Relay Satellite (MILSTAR) geostationary satellite also has mobile-satellite capability in this band, with a transponder that provides four Air Force Satellite Communications (AFSATCOM IIR) channels and a fleet broadcast channel.

The Navy has launched the next generation mobile satellites, termed the Multiple User Objective System (MUOS) that use the bands 243.525-270.05 MHz and 280-320 MHz. The MUOS is undergoing testing and is not fully operational as of September, 2014. The Navy has awarded contracts for the MUOS, and overall, the MUOS will be $6.4 billion system. The MUOS enables communications to various terminal devices such as handhelds, laptops, and personal communications units. To support legacy systems, the MUOS will use a narrowband system of 64 kbps/channel and below. The MUOS will use wideband-code-division-multiple-access (WCDMA) technology, the same technology as some forms of the third generation (3G) commercial cellphone technology. The capacity is 4 Mbps per antenna beam.

In general, the band 225-328.6 MHz is reserved for military uses by North Atlantic Treaty Organization (NATO), its member nations, and other U.S. allies. The band is harmonized among NATO-member nations for secure communications.

(Information extracted from the NTIA Federal Government Spectrum Use Reports, dated December 1, 2015)

Frequency Bands
Band	Use	Service	Table
225 - 322 MHz	Military mobile-satellite communications	Mobile-satellite	F
335.4 - 399.9 MHz	Military mobile-satellite communications	Mobile-satellite	F

External Links:

FAS Space Policy Project, DSCS III Satellite Description (fas.org)

NTIA Spectrum Use Summary 225.0-328.6 MHz

UHF-MILSATCOM frequencies (RadioReference.com)

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Area Common User System (ACUS) (NTIA)

The military agencies use the band 225-328.6 MHz for tactical and non-tactical land mobile and fixed service point-to-point communications. The most extensive use is by the Army's Area Common User System (ACUS), consisting of both land mobile and fixed communications systems. The mobile version uses mobile subscriber equipment (MSE) that functions like a cellular communications network, capable of providing communications to many users.

The fixed communications part of the ACUS is a high capacity line-of-sight point-to-point radio system. The radio provides voice and data communications over paths up to 70 miles. The system can use various data rates, with the highest being 34 Mbps, and it has a feature that provides a spectrum scan to detect spectrum congestion to identify frequencies to maximize link availability.

In general, the band 225-328.6 MHz is reserved for military uses by North Atlantic Treaty Organization (NATO), its member nations, and other U.S. allies. The band is harmonized among NATO-member nations for secure communications.

(Information extracted from the NTIA Federal Government Spectrum Use Reports, dated December 1, 2015)

Frequency Bands
Band	Use	Service	Table
225 - 328.6 MHz	Military land mobile communications	Mobile	F
225 - 328.6 MHz	Military fixed point-to-point communications	Fixed	F

External Links:

NTIA Spectrum Use Summary 225.0-328.6 MHz

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Federal Maritime Mobile Communications (NTIA)

The Navy, Coast Guard, and NASA use the band 225-328.6 MHz for tactical and non-tactical operations such as ship-to-air-to-ship and ship-to-ship for clear and secure voice communications. The Coast Guard also uses the band for a secure data communications link.

In general, the band 225-328.6 MHz is reserved for military uses by North Atlantic Treaty Organization (NATO), its member nations, and other U.S. allies. The band is harmonized among NATO-member nations for secure communications.

(Information extracted from the NTIA Federal Government Spectrum Use Reports, dated December 1, 2015)

Frequency Bands
Band	Use	Service	Table
225 - 328.6 MHz	Federal Ship-to-Shore and Ship-to-Ship Communications	Mobile	F

External Links:

NTIA Spectrum Use Summary 225.0-328.6 MHz

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Military Aeronautical/ATC Communications and Telemetry (NTIA)

The military agencies, National Guard units, the Coast Guard, and the FAA are the heaviest users of the band 225-328.6 MHz, using the band for critical air-to-ground-to-air communications systems. The military agencies and National Guard units use the band 225-328.6 MHz for various types of aeronautical communications, e.g., for training flights and air-traffic-control functions such as ground control, approach control, enroute aircraft separation, and in-flight refueling services. The Air Force, Army, Navy, and the FAA have thousands of frequency assignments for air-to-ground-to-air communications in the band 225-328.6 MHz. Most of these assignments are to ground stations.

The Coast Guard uses the band on its maritime search-and-rescue aircraft and other aircraft for air-to-ground-to-air communications. The military agencies, National Guard units, and the FAA make extensive use of the band 225-328.6 MHz which alleviates possible impact of the national airspace civilian air-to-ground-to-air communications operating in the bands within 117.975-137 MHz. Thus, the Federal use of the band 225-328.6 MHz for aeronautical communications plays an important part in national defense and security, and to control the nation's airspace.

The band 225-328.6 MHz is also used for essential communications by a number of other agencies such as NASA, DOE, and DOC. NASA uses the band for aircraft communications, and for International Space Station (ISS) communications during Extravehicular Activity (EVA); and DOC uses the band on National Oceanographic and Atmospheric Administration (NOAA) hurricane-hunter aircraft, and on ground stations to communicate with other hurricane-hunter aircraft.

The military agencies use the band 225-328.6 MHz for a major tactical communications system to provide anti-jam, secure, frequency-hopping radio communications for tactical air-to-air and air-to-ground-to-air communications. The uses include coordination and vectoring of aircraft to targets, and large scale training exercises.

For example, the major radio communications systems are deployed on all rotary wing aircraft, and are used by all operational aviation units, air traffic services, and units. The radio communications system enables interoperability communications among Air Force, Navy, Army, and NATO units.

The Navy makes extensive use of the band for aeronautical telemetry, and DOE also uses the band for this purpose. The Navy uses the band for flight testing of military aircraft. The military agencies also use this band for telemetry systems for rocket testing.

In generall, the band 225-328.6 MHz is reserved for military uses by North Atlantic Treaty Organization (NATO), its member nations, and other U.S. allies. The band is harmonized among NATO-member nations for secure communications.

(Information extracted from the NTIA Federal Government Spectrum Use Reports, dated December 1, 2015)

Frequency Bands
Band	Use	Service	Table
225 - 328.6 MHz	Military aeronautical communications and telemetry	Mobile	F

External Links:

NTIA Spectrum Use Summary 225.0-328.6 MHz

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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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Military Battle Simulation Systems (NTIA)

The military agencies use the band for research, development, testing, and evaluation of various types of communications and sensing systems. The military agencies operate training center instrumentation systems in this band for data links connecting battle simulation systems on participants' platforms (airborne, shipborne, or surface) to central processing facilities.

In general, the band 225-328.6 MHz is reserved for military uses by North Atlantic Treaty Organization (NATO), its member nations, and other U.S. allies. The band is harmonized among NATO-member nations for secure communications.

(Information extracted from the NTIA Federal Government Spectrum Use Reports, dated December 1, 2015)

Frequency Bands
Band	Use	Service	Table
225 - 328.6 MHz	Military battle simulation systems	Mobile	F

External Links:

NTIA Spectrum Use Summary 225.0-328.6 MHz

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Occupancy Measurements (10)

Engineering Data

	Lower Frequency	Center Frequency	Upper Frequency
Frequency	235 MHz	251 MHz	267 MHz
Wavelength	1.3 m	1.2 m	1.1 m
Band designator(s)	VHF	VHF	VHF
Isotropic collecting area	1,295.1 cm²	1,135.2 cm²	1,003.2 cm²
Free space loss (1 m)	19.9 dB	20.4 dB	21.0 dB
Free space loss (1 km)	79.9 dB	80.4 dB	81.0 dB
Free space loss (10 km)	99.9 dB	100.4 dB	101.0 dB
Free space loss (100 km)	119.9 dB	120.4 dB	121.0 dB
Free space loss (1000 km)	139.9 dB	140.4 dB	141.0 dB
Free space loss (35,786 km = GEO orbit)	170.9 dB	171.5 dB	172.1 dB
Free space loss (378,370 km = Moon)	191.4 dB	192.0 dB	192.5 dB