standards radio carriers. Users of radio are discouraged from transmitting of equipment performance which are demanded in order to provide unnecessarily high power. Encouragement is given to the use of well for the possibility of access by a much larger number of systems, designed receivers and antennas, capable of making the best of a many of which are never implemented. Planning for this purpose medium which is interference limited in some frequency bands and meets a need that many administrations feel acutely, but it does some locations. These general requirements are undemanding, but nothing for economy in system costs or spectrum use for the planned more stringent measures are applied in particular situations and service, and it may significantly impede the use of the same band specific frequency bands where the need is evident; some of these for sharing services. latter cases are mentioned in Sections 26.6.2 to 26.6.4. Above all, there is close collaboration between administrations at 26.6.3 International regulations and two main levels. In the absence of overriding political inhibitions, recommendations they co-operate to ensure that their frequency assignments do not cause or suffer interference. And they share expertise, in the tech- In certain radio services and in specified frequency bands, as indi- nology of telecommunications and also in developing a precise cated in Section 26.6.2, sets of spectrum efficient operational prac- statistical basis for predicting radio propagation conditions for tices and technical standards have been adopted as part of a plan. wanted and interfering signals. Exceptionally, in the fixed satellite service using geostationary satellites, which is ill suited in precise planning, a similar though 26.6.2 International frequency band planning less comprehensive set of international practices and standards is being adopted in all bands as they come into full use, to raise the efficiency with which this service uses its transmission medium. There are various forms of plan, drawn