The Committee on Radio Astronomy Frequencies (CRAF) is a committee of
the European Science Foundation (ESF).
Local issues for the Radio Astronomy Service are often different in each country. Usually they are terrestrial problems related to, for example: broadcast, fixed service, radiolocation, etc. 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.
The number of wind farms in Europe has grown significantly in the last 10 years and this poses an increasing threat to Radio Astronomy Stations. CRAF has produced a report on "Wind Farms and Radio Astronomy" and has recently held a workshop on the "Impact of Wind Turbines on Radio Astronomy".
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. One of CRAF's activities is to advise the radio astronomers in the individual countries with the work on the protection of radio frequencies allocated to the Radio Astronomy Service.