Radio Frequency Management Division
The Radio Frequency Management Division (RFMD) is responsible for ensuring the availability and usability of RF spectrum to radio users in the Department of Commerce (DOC). Additional information can be found in the Department Administrative Order 201-39. This work involves:
- obtaining authorization to use new and existing radio systems, and ensuring that such systems meet relevant federal standards
- coordination of National Oceanic and Atmospheric Administration (NOAA) satellite systems with domestic and foreign space networks to ensure compatible operation
- prevention and resolution of interference involving DOC and other systems through coordination with other agencies and the private sector
- participation in DOC Continuity Of Operations (COOP) plans to ensure survivability of frequency management within DOC
- negotiation with other government agencies, the private sector, and foreign and international entities on behalf of Commerce and/or the U.S.A. to ensure the future availability of spectrum and the absence of interference
The RFMD represents the DOC and its various elements in several fora, including the Interdepartment Radio Advisory Committee (IRAC) and its various subcommittees, and at meetings of international organizations dealing with frequency matters. The latter includes the International Telecommunications Union (ITU), OAS Commission for Inter-American Telecommunications (CITEL), Space Frequency Coordination Group (SFCG) and a Steering Group on Radio Frequency Coordination of the World Meteorological Organization (WMO).
Within the DOC, the largest user of radio is NOAA. Several radio frequency bands are utilized by various platforms supporting NOAA’s mission goals, including meteorological satellites, in situ fixed and mobile platforms (e.g., buoys, weather stations, ships, aircraft), radiosondes, and other data collection platforms.
Representations of the radio frequency spectrum allocation for the U.S. as published by the Department of Commerce National Telecommunications and Information Administration (NTIA) can be obtained as visual and text-based representations.
NOTE: All DOC radio frequency spectrum use requires NTIA spectrum certification and authorization. Please contact RFMD in the early stages of planning and acquisition of any equipment or systems which require use of radio frequency spectrum to ensure the needed spectrum will be available and can be protected.
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Originally, radio technology was called 'wireless telegraphy', which was shortened to 'wireless'. The identity of the original inventor of radio, at the time called wireless telegraphy, is contentious. The controversy over who invented the radio, with the benefit of hindsight, can be summed up with the answer to who invented 'wireless transmission of data'. Nikola Tesla holds the US patent for this. The founding principles and inventions of wireless technology can be found in the lectures and patent record of Tesla. It was also later pioneered by Jagdish Chandra Bose and Guglielmo Marconi. A wireless set was the radio receiver, referring to its use as a wireless telecommunication station.
In modern usage, wireless is a method of communication that uses low-powered radio waves to transmit data between devices. The term refers to communication without cables or cords, chiefly using radio frequency and infrared waves. Common uses include the various communications defined by the Infrared Data Association (IrDA) and the wireless networking of computers. These include various types of fixed, mobile, and portable two-way radios, cellular telephones, personal digital assistants (PDAs), wireless laptop computers and other portable devices employing Wi-Fi and 3G communications technology. Other examples of wireless technology include GPS units, garage door openers, wireless computer mice, keyboards and headsets, satellite television and cordless telephones.
Low-powered radio waves, such as those used in networking to transmit data between devices, are often unregulated. High-powered transmission sources usually require government licenses to broadcast on a specific wavelength. This platform has historically carried voice and has grown into a large industry, carrying many thousands of broadcasts around the world.
1. Spectrum XXI (SXXI)
The SXXI (Spectrum management in the 21st century) software was developed under the management and direction of the Department of Defense Joint Spectrum Center (JSC) and the National Telecommunications and Information Administration (NTIA). SXXI was developed to fulfill a need to automate many processes and to standardize the spectrum management processes throughout the Federal Government. The primary capabilities of SXXI focus on Frequency Assignment, Interference Analysis, Equipment Certification, Electronic Warfare (EW) Support, Frequency Engineering, and Allotment Plan Generation. More information on these capabilities can be found by downloading the Spectrum Management in the 21st Century PDF.
2. NTIA Government Master File
The Government Master File (GMF) contains records of the frequencies assigned to all US Federal Government agencies in the US and its possessions. The master file is updated daily.
Each NOAA bureau and each DOC component organization has a designated liaison through which operational units within DOC request frequency assignments. Each liaison forwards the request for frequency assignments to RFMD for completion and submission to NTIA. A list of the DOC/NOAA frequency liaisons is located in the Contact Us tab. Proposals for frequency assignments are submitted electronically by RFMD to NTIA. Each member agency on the Frequency Assignment Subcommittee (FAS) reviews each proposal along with the NTIA action officer assigned to that proposal. Each person reviewing the proposal looks for conformance with the NTIA Manual of Regulations and Procedures for Federal Radio Frequency Management.
Each agency representative is also looking at each proposal for potential interference to his agency's present operations. Upon approval on a frequency assignment by the FAS, NTIA issues a radio frequency authorization for that assignment and the assignment is recorded in the NTIA Government Master File (GMF) of Frequency Assignments.
Commerce, like all other member agencies, manages its existing frequency assignments in the GMF. Experimental assignments are only granted authority for a limited time, and RFMD works with the appropriate liaison either to allow existing assignments to expire if no longer in operation or to request renewal by NTIA for continuing experimental operations. Permanent operational assignments are required to be reviewed every five years for accuracy and retention. RFMD has ongoing procedures to work with each liaison to review and update each assignment as appropriate.
- Basic Elements of Spectrum Management
- International Telecommunications Union (ITU)
- National Telecommunications and Information Agency (NTIA)
- Inter-American Telecommunication Commission (CITEL)
- Conference of European Postal and Telecommunications Administrations (CEPT)
- Federal Communications Commission (FCC)
- U. S. Department of Commerce (DOC)
- National Oceanic and Atmospheric Administration (NOAA)
- National Weather Service (NWS)
- Lloyd's Satellite Constellations
The Inter-American Telecommunication Commission endeavors to make telecommunications a catalyst for the dynamic development of the Americas by working with governments and the private sector. Under the auspices of the Organization of American States (OAS), it resides in Washington, DC, USA. It has 34 Member States and over 200 Associate Members. It has been entrusted by the Heads of State at the Summits of the Americas with specific mandates to intensify its activities in key areas.
CITEL has technical autonomy to perform its functions within the limits prescribed by the OAS Charter, its statutes and the mandates of the General Assembly. Its objectives include facilitating and promoting the continuous development of telecommunications in the Hemisphere.
CITEL has a Permanent Executive Committee (COM/CITEL) consisting of eleven members, and two Permanent Consultative Committees, Permanent Consultative Committee I: Public Telecommunication Services, and Permanent Consultative Committee II: Radiocommunications and Broadcasting whose members are all Member States of the Organization, Associate Members that represent various private telecommunications associations or companies, permanent observers and regional and international organizations.
The mandates for the two permanent committees and the Steering Committee are as follows:
Permanent Consultative Committee I: Public Telecommunication Services
PCC.I: Focuses on standards coordination, planning, financing, construction, operations, maintenance, technical assistance, equipment certification processes, rate principles, and other matters related to the use, implementation, and operation of public telecommunications services in the Member States.
Permanent Consultative Committee II: Radiocommunications Including Broadcasting
PCC.II: Deals with standards coordination, planning, and full and efficient use of the radio spectrum and satellite orbits, as well as matters pertaining to radiocommunication services in the Member States. Acts as a technical advisory body within the Inter-American Telecommunication Commission with respect to standards coordination, planning, operation, and technical assistance for the broadcasting service in its different forms.
The Steering Committee is formed by the Chair and Vice-Chair of COM/CITEL and the Chairs of the PCCs. The Committee is responsible for proposing to COM/CITEL the review of CITEL's program of activities to ensure that the Commission is responding to of its members' needs, assuring the continued effective and efficient use of resources and, when it deems necessary, to propose additional initiatives for the COM/CITEL agenda. The Executive Secretary acts as Secretary of the Committee.
The International Telecommunications Union (ITU) is a specialized U.N. agency which coordinates telecommunications matters among member countries. Use of the radio spectrum is largely coordinated through the Radiocommunications Sector (ITU-R), which develops technical coordination criteria and standards for such use, and through various periodic conferences attended by member nations of ITU. Perhaps the best known of these is the series of World Radiocommunication Conferences (WRCs, formerly known as World Administrative Radio Conferences. ) The ITU is headquartered in Geneva, Switzerland.
- ITU Tower Building (Entrance: Avenue Giuseppe-Motta)
- ITU Varembé Building (Entrance: 6, Rue de Varembé)
- ITU Montbrillant Building (Entrance: 2, Rue de Varembé)
- EFTA European Free Trade Association
- CICG Geneva International Conference Centre
- Underground garage (Parking des Nations)
- Le Salève
The National Telecommunications and Information Administration (NTIA) is an element of the Department of Commerce which has among its responsibilities the job of exercising the President's authority under The Communications Act of 1934, As Amended for regulating use of the radio spectrum by agencies of the Federal Government. It is distinct from RFMD in that it is responsible, through the Secretary of Commerce, to the President. RFMD is responsible to the Secretary, just as the frequency management offices of the other agencies are responsible to the heads of their respective organizations.
The Interdepartment Radio Advisory Committee (IRAC) was established in 1922 to advise the president and now advises the National Telecommunications and Information Administration (NTIA) on telecommunications policy, technical and other matters affecting the Federal agencies. It comprises representatives from twenty Federal agencies and has observers from several more. The IRAC has several standing subcommittees, including:
- The Spectrum Planning Subcommittee (SPS), which reviews major radio systems planned by Federal agencies to ensure that they comply with applicable Federal equipment standards and communications policy, and they can be supported in the bands which their proponents plan to use.
- The Frequency Assignment Subcommittee (FAS), which reviews proposed frequency assignments (see below) in Federal bands to determine their compatibility with existing operations and applicable rules.
- The Technical Subcommittee (TSC), which develops technical standards for Government radio equipment.
- The Radio Conference Subcommittee (RCS), which develops Government positions for upcoming international conferences.
- The Space Systems Subcommittee (SSS), which handles the coordination of Federal space systems with other domestic and foreign satellites
- The Emergency Planning Subcommittee (EPS), which deals with emergency spectrum planning.
- The Aeronautical Standards Groups (ASG), which coordinates assignments for Federal aircraft issues (bands, trends, net users, net industry).
The electromagnetic spectrum is a continuous band of frequencies extending from radio waves to gamma waves, corresponding to the very lowest frequencies to the highest possible frequencies. The lowest frequencies (longest wavelengths) are associated with the lowest energies while the highest frequencies (shortest wavelengths) are associated with the highest energies, based on Planck’s law, where is the energy at frequency (measured in Hertz or cycles per second) and is Planck’s constant. A pictorial representation of the Electromagnetic Spectrum is shown below.
Typical sources of radio waves include AM, FM and Shortwave broadcasts, television (VHF and UHF channels), weather radio, aircraft communications, wireless devices, mobile phones and Global Positioning Systems (GPS). Microwave applications include ground- and satellite-based radar, radio astronomy and communications satellites. Since the earth and its atmosphere are natural sources of microwave and infrared radiation, these frequencies are also monitored by environmental satellite instrumentation to determine the properties of land, ocean and atmosphere for weather forecasting and climate monitoring purposes. Note that the visible portion of the spectrum occupies only a very small fraction of the full electromagnetic spectrum. Space-borne astronomical observatories monitor many of the higher energy frequencies (ultraviolet, X-rays, and gamma rays) to determine the state of solar activity (e.g., “space weather”) as well as study the properties of other celestial phenomena such as nebulae, pulsars and quasars.
A useful tool for converting between electromagnetic frequency and wavelength, as well as for understanding the applications of various segments of the spectrum, is this provided tool.
The meteorology radio frequency bands are a primary target of industry. Cellular, Mobile Satellite Service (MSS) and many other commercial systems would be best served by having the same spectrum available to them worldwide. This would simplify the design of their satellites and allow use of the same ground terminals around the globe. Coincidentally, the primary meteorological bands (137-138 MHz, 400.15-406 MHz, 1670-1710 MHz and 2700-2900 MHz) are allocated to meteorology worldwide and, if captured by industry, would provide them with exactly the sort of arrangement they would most like to have. The results show in the history of WARC-92 through WRC-2000: the industry is working to obtain additional parts of these bands.
The discussion takes place in terms of band sharing with meteorology, but "sharing" has several meanings in the ITU's International Radio Regulations. One definition includes the removal of present occupants from part of a band so it can be given over to the new users. This form of "sharing" is, in fact, expropriation. Other types of sharing involve limiting the use by both occupants in a way which permits both to use the band. The U.S. has decided that the MSS will share 400.15-401 MHz by limiting its emissions so as not to interfere with the meteorological satellites using the band (time sharing) and with radiosondes by having the radiosondes go somewhere else. The U.S. proposals to WRC-97 involved limiting the power flux density of MSS satellites in 402-405 MHz so as not to interfere with radiosondes (thus mandating the use of spread spectrum by the MSS) and removing radiosondes from 405-406 MHz, making this the exclusive domain of MSS systems. These U.S. proposals failed to be adopted at the WRC.
The foreign proposals seen at WRC-97 respecting the 1675-1683 MHz band would have required the removal of radiosondes from this spectrum. In the United States radiosondes are barred from future use of 1670-1675 MHz by OBRA-93 (discussed above) and would thus have to use the spectrum above 1683, where they would interfere with meteorological satellite downlinks. GVAR (GOES VARiable data) occupies the region 1682-1690 MHz; WEFAX, EMWIN and other data are in 1690-1697 or so, and HRPT from the polar meteorological satellites occupies 1697-1710 MHz. Clearly, there is no place for the radiosondes to go that would not cause problems for meteorological satellite receivers. Fortunately, these issues were resolved at WRC-2003, where the MSS was given a new allocation at 1668-1675 MHz with protection of meteorology required in certain countries.
Those designing meteorological satellite receivers need to bear in mind that the bands will be changing significantly in the next few years. Where in the past they were the exclusive domain of meteorological systems, they may soon be occupied as well by large numbers of commercial satellites. Receivers thus must be capable of functioning properly in the presence of additional signals, some fairly strong, operating in adjacent channels. Selectivity, adjacent channel rejection and resistance to overload will become increasingly important in coming years and designing for minimum cost may no longer produce adequate equipment.
In 137-138 MHz, there have already been complaints of interference from the MSS satellites operating in the band. Receivers having excessive bandwidth are vulnerable to MSS satellites operating in adjacent channels to those used by meteorological satellites.
In 1675-1700 MHz, there have been instances of interference to GVAR and WEFAX receivers caused by radiosondes operating in the adjacent bands. Tests reveal this interference to result from excessive bandwidth and non-linearity in the front end of satellite receivers.
Contact: James L. Mentzer
Phone: (301) 628-5649
Contact: Carmelo Rivera
Phone: (301) 628-5646
Contact: David Franc
Phone: (301) 628-5647
Contact: Jeremiah Sullivan
Phone: (301) 628-5645
If you would like to see a list of all of the ITU events scheduled go to: