The Committee on Radio Astronomy Frequencies (CRAF) is a committee of
the European Science Foundation (ESF).
On behalf of European radio astronomers concerned with interference in the frequency bands
used for radio astronomy, the European Science Foundation had formed an ESF Committee on Radio
Astronomy Frequencies (CRAF). The task of the Committee is to coordinate activity to keep the
frequency bands used by radio astronomers free from interference. It will attempt to fulfil this
task by:
- Co-ordinating the radioastronomy case in Europe in discussions with the major public and
private telecommunications agencies.
- Acting as the European voice in concert with other groups of radio astronomers in discussions
within the international bodies that allocate frequencies.
- Initiating and encouraging scientific studies aimed at reducing interference at source, as
well as the effects of interference.
The Committee is self-managed from its Office at the Netherlands Foundation for Research in Astronomy: Ir.H.C.Kahlmann is the Chairman and Dr.T.A.Th.Spoelstra the Secretary.
The Committee acts also to help EISCAT - the European Incoherent Scatter Scientific Association - whose expensive radar equipment and important passive experiment in the polar ionosphere faces similar severe interference problems. The Director of EISCAT (Kiruna, Sweden), participates in the Committee as an observer.
The Committee became operational in July 1988. Since that time attention has been paid to current problems in the Radio Regulations as well as technical aspects such as interference reduction techniques.
Very important is a general World Administrative Radio Conference, WARC, which will be held in 1992 and at which all allocations between 0.5 and 3 GHz will be open for discussion and re-allocation, while the allocation of frequencies above 20 GHz to new services will be considered. CRAF got strong warnings at meetings on electromagnetic compatibility in the course of 1990 that the radio astronomy service to fight with all effort for its survival. Therefore, it expects that in the years before this meeting much work will need to be done in lobbying, explaining technical considerations, etc. to obtain support for radio astronomy frequencies. In preparation for the WARC 1992, CRAF issued its "Views of the European Science Foundation Committee on Radio Astronomy Frequencies concerning Frequency Allocations for the Radio Astronomy Service in the Bands above 0.3 GHz and in Preparation for the World Administrative Radio Conference - 1992" (CRAF-90-1C) in which its positions are explained.
Special attention was paid to current frequency allocation and spectrum management problems in Italy between the Italian private TV network (TV-5) and the Istituto di Radioastronomia in Bologna about the use of channel 38 (608 - 614 MHz). In spite of actions taken by CRAF and the Italian radio astronomers, the Italian radio astronomers had to abandon the attempts together with the hope to ever observe the sky in this frequency band.
Important items the Committee has discussed are:
- the increased interference in the 18 cm band (OH emission) by GPS transmissions: monitor
observations indicate that the peak interference exceeds the CCIR recommendations by about
13 dB)
- the increased thread for the 18 cm band by the Radio Determination Satellite System, RDSS,
on which CRAF explained its position in its views on the LOCSTAR proposal for blanking
radiotelescopes when a detectable LOCSTART transmission occurs (CRAF-90-2A)
- the increased threat by new use of the 18 cm by the EUTELSAT network
- a proposal by some countries to commercialize frequency management
- a proposal to install 1.5 GHz space radar
- a proposal to install 1.5 GHz satellite for broadcasting sound.
Some progress has been made in the development of techniques for frequency monitoring and software to alleviate interference problems. Further work on the definition of a number of technical concepts is required before these techniques can be used at observatories.
The Committee has been accepted by the CEPT as a body to discuss with and is invited to its meetings, while it also gets all documentation and it can communicate directly to CEPT.
CRAF was informed about good perspectives for the acceptance of a proposed NATO-CCMS study to achieve a more alert administrative control of frequency allocation matters including international judicial support.