The Committee on Radio Astronomy Frequencies (CRAF) is a committee of
the European Science Foundation (ESF).
Regional problems for the Radio Astronomy Service are different per geographical region. Usually they are terrestrial problems related to e.g. broadcast, fixed service, radiolocation. In many cases protection can be achieved by proper filtering of the transmitters, the use of modulation techniques to reduce out-of-band emission and spurious emission, i.e. to avoid spectrum pollution or by adequate management of the spectrum to avoid allocations to active services adjacent or otherwise too close to frequencies used by the Radio Astronomy Service. Also the establishment of a coordination area will reduce the level of interference suffered by the earth station of the passive spectrum user.
At a European scale, the ESF Committee on Radio Astronomy Frequencies, CRAF, coordinates the efforts for the protection of radio spectrum bands used by the Radio Astronomy Service and other passive applications.