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International Registration

The Radio Regulations is an international treaty that includes among its objectives: facilitating the efficient and effective use of the operation of all radio services, and assisting in the prevention and resolution of cases of harmful interference between radio services of different administrations. International allocations may be (and generally are) implemented by each country, but there is no obligation to do so, as every country retains sovereign rights regarding spectrum use within its borders. While there is no requirement to conform to the international allocations, in general, it is convenient to do so. Therefore, an international radio astronomy allocation does not necessarily provide protection from interference, rather the international system provides a framework for protection. In addition, administrations may provide protection to observatories through regulatory action other than a frequency allocation (e.g. through the establishment of coordination zones). Some articles of the Radio Regulations related to registration of radio stations (in particular radio astronomy stations, the rights of stations registered in the Master International Frequency Register (MIFR) and to resolution of cases of interference are reproduced below (some an abridged form).

4.4 Administrations...shall not assign to a station any frequency in derogation of either the Table of Frequency Allocation...or the other provisions of these Regulations, except on the express condition that such station, when using such a frequency assignment, shall not cause harmful interference to, and shall not claim protection from harmful interference caused by, a station operating in accordance with ...these Regulations.

4.6 For the purpose of resolving cases of harmful interference, the radio astronomy service shall be treated as a radiocommunication service. However, protection from services in other bands shall be afforded the radio astronomy service only to the extent that such services are afforded protection from each other.

8.1 The international rights and obligations of administrations in respect of their own and other administrations frequency assignments shall be derived from the recording of those assignments in the Master International Frequency Register (MIFR)...

8.3 Any frequency assignment recorded in the Master Register with a favorable finding under 11.31 shall have the right to international recognition.... this right means that other administrations shall take it into account when making their own assignments in order to avoid harmful interference.

11.12 Any frequency to be used for reception by a particular radio astronomy station may be notified if it is desired that such data be included in the Master Register.

11.30 Each notice shall be examined:
      11.31 a) With respect to its conformity with the Table of Allocations and other       provisions of these Regulations....
      11.31.2 The other provisions shall be identified and included in the Rules of       Procedure.
      11.31.3 Notices relating to radio astronomy stations are examined with respect to       11.31 only

15.25 Administrations shall cooperate in the detection and elimination of harmful interference, employing where appropriate the facilities described in Article 16 (monitoring) and the procedures detailed in this section.


International registration of radio astronomy stations offers the following advantages:

  • Recognition – The ITU and the international radio engineering community at large doesn’t “know” that a given observatory exists until told so (don’t assume that just because you operate the world’s largest dish, everyone knows about it, much less that everyone cares about its sensitivity!)

  • In the case of some bands used by non-geostationary satellite systems, a commitment on behalf of the registering administration regarding compliance with aggregate (unwanted emission) power flux-density limits in a neighboring radio astronomy band, at registered observatory sites.

  • A mechanism to initiate negotiations between administrations in case harmful interference occurs (telescope in country A interfered by transmitters in country B). It is much more difficult to do so when the telescope is not registered.

  • Demonstration of use of the band by the radio astronomy service to the international community, not readily noticeable to active users of the spectrum by other means.

Data Requirements for Notification of Radio Astronomy Assignments

The data requirements for registration of radio observatories are listed in Appendix 4, Annex 2 of the Radio Regulation, along with those necessary for registration of Earth stations of satellite networks. Annex 2B provides a quick look table of the necessary parameters. These parameters may only be altered by a World Radiocommunication Conference (WRC). Some changes were adopted at WRC-03, and proposals for others may be introduced at WRC-07. Current data requirements are:

  • Name of the Radio Observatory
  • Registering Administration
  • Geographical Coordinates: Latitude and Longitude in (DD/MM/SS, to 10th of arcmin)
  • Date on Which Use of Frequency Begins
  • Operating Agency
  • Antenna Type, Dimensions, Aeff and Angular Coverage
  • Center Frequency of Band Observed
  • Bandwidth (in kHz)
  • Tsys (K) Referred to the Output of the Antenna
  • Observation Class (A/B)*
  • Single Dish (or closely connected array) or VLBI Dish?
  • Minimum Elevation Angle ?min at which the Radio Astronomy Station Conducts LBI Observations in the Band
  • * Class A and B stand for Non-sensitive and Sensitive Observations, respectively. Other than Routine Solar Patrol Instruments, All Telescopes Should Register Class B Observations

    How to Register?

    International registration must be submitted to the ITU through the Administration on whose territory the radio telescope is located. US telescopes (government and non-government operated) may be registered by contacting:

          Electromagnetic Spectrum Manager
          National Science Foundation                     Phone: 703-292-4896
          4201 Wilson Boulevard, Room 1045          FAX: 703-292-9034
          Arlington, VA 22230