ectrum were in use and they were used for point-to-point Often the radiation from such equipment is wide band and noise communication between fixed stations, communication with and like but there may be a dominant spectral component. The designers between mobile stations, mainly ships, and broadcasting. These and users of such equipment are urged to minimise both kinds of applications were called the fixed service, the mobile service and radiation. In addition, however, a dozen frequency bands spanning the broadcasting service respectively. By international agreement the spectrum from 6MHz to 250GHz have been identified by the the spectrum then in use was divided into several frequency bands, ITU in collaboration with the International Electrotechnical Com- different bands being allocated for each service. mission (IEC), to be used for Industrial, Scientific and Medical This concept of dividing the spectrum between the different kinds (ISM) equipment which has a narrow band radiation characteristic. of radio service is still found to be wise and its application has been These bands are also allocated for radio use, most commonly the extended and elaborated to serve modern requirements. The inter- fixed or the radiolocation services, it being understood that inter- national table of frequency allocations (ITU, 1990, Article 8) now ference from ISM equipment must be tolerated in these bands. International spectrum management 26/7 26.4 International spectrum management 28MHz to a technical examination to confirm that interference is unlikely to arise. However, if the station lies within the co-ordina- 26.4.1 Overview tion area of an earth station operating in the same frequency band, the IFRB will not register a new assignment until its use has been co-ordinated with the earth station. Similar limitations apply in Almost all radio systems which provide telecommunications fa- frequency bands around 12GHz that have been planned for the cilities fall into two broad categories, namely systems that link fixed broadcastin