administrations for assignment to stations within their juris- there are agreed mandatory procedures governing the consultation diction. See also Section 26.6.2. process (see Section 26.2.3.). However, informal contacts are used International frequency assignment plans have been formally if consultation between the administration of adjacent countries is agreed for certain other frequency bands. These plans specify likely to be sufficient. Then: virtually all of the details of the foreseen assignments in a frequency band, including the location of stations, as well as If an assignment, when activated, may be capable of causing many of the technical parameters of the foreseen emissions. See interference abroad or if it is to be used for an international link, also Section 26.6.2. details of the assignment must be notified to the International 4. In situations where it is difficult to identify all of the adminis- Frequency Registration Board (IFRB), one of the organs of the trations that might be affected by a new frequency assignment, informal liaison between administrations would not be satisfac- The IFRB examines each notice to verify that the assignment is tory. Detailed mandatory international frequency co-ordination in accord with international agreements, and that any manda- procedures have been agreed in such cases. tory steps have been taken to ensure that interference will not 5. Sharing constraints, such as constraints on transmitted power, occur to recognised foreign assignments. In some frequency are imposed on stations to limit the interference that other bands below 28MHz, in which it is particularly difficult to stations will suffer to an acceptably low level, in cases where assess whether interference is likely to occur, the IFRB itself frequency co-ordination would be impracticable. makes a technical examination of the interference prospects. If the newly-notified assignment survives these examinations, it Applications of these various specific measures are reviewed in is registered in the Master 