Brief history of CRAF

1. The conception

In de mid-1980s European radio astronomy experienced various threats by sources of radio interference. These threats increased gradually into challenges for radio astronomers. Among these developments, were the French plans to build a TV transmitter at Lille and at the top of the Eiffel-tower in Paris for transmissions in the channel 38 (608-614 MHz) into northerly directions, i.e. to serve Belgium and consequentially, affecting the radio astronomy in the Netherlands. Observations at the Westerbork Radio Observatory would have been severely degraded in the band 608-614 MHz. However, due to some internal French political problems, the Eiffel-tower plan was relatively soon abandoned.

In the Summer of 1985 Hans Kahlmann and Titus Spoelstra discussed the continuous increase in interference to radio astronomy operations with Willem Baan (Arecibo Radio Observatory), when he visited Dwingeloo Radio Observatory. They developed a plan trying to form a kind of forum for European radio astronomers to address these matters with a concerted voice at a European regional level. Since the 1960s the radio astronomers in the USA had such a forum in the Committee on Radio Frequencies of the US National Research Council (CORF). Hans and Willem considered that a possible European “body” could work in a similar manner like CORF.

Titus Spoelstra started to work on the organization of a first meeting of representatives from radio astronomy stations concerned with the issues of interference to radio astronomy. Hans addressed the regulatory aspects of the issue. The first step was to identify contact nodes. This tedious basic administrative work had to be done from scratch. In addition it appeared necessary to collect and map all European radio regulatory bodies whilst noting that some organizations change name or mandate from time to time.

On March 31st – April 1st, 1987, a meeting took place at Paris Observatory. Some key persons and the press were invited to reflect on radio interference as a major problem for radio astronomy in Europe and to pay attention to this issue in publications. Paris was chosen because the reason for the meeting was in France. Representatives from 6 European radio observatories participated in this meeting. Also the European Space Agency participated in the meeting and its frequency manager advised the meeting how it could proceed to protect radio astronomy.

The meeting agreed to try to continue as a group. The group agreed to take the working methods of the Committee on Radio Frequencies of the US National Research Council as a starting approach. The chairman of the Paris meeting, Hans Kahlmann, was tasked to try to develop a working structure for the group.

2. First steps

The participants of the Paris meeting agreed to try to form a kind of sister organization to CORF. They also desired to assist the Inter-Union Commission for the Allocation of Frequencies for Radio Astronomy and Space Research, IUCAF. IUCAF is a joint commission of the International Union of Radio Sciences, URSI, the International Astronomical Union, IAU and the Committee on Space Research, COSPAR. These three are amongst the international scientific unions which under the International Council of Scientific Unions, ICSU, devolve from UNESCO.

BUT, this “arbitrary” group of worried radio astronomers was in need of an organizational “umbrella” to be willing to serve in support of its activities. This structure would have entitled that group of radio astronomers to use an official letter head of this “umbrella” organization and to present itself as a pan-European organization at relevant fora. It was considered that such an “umbrella” must have characteristics similar to the nature of the science radio astronomy, specifically that it must be not political nor commercial, but to serve the pure science. Noting this, the European Science Foundation (ESF) at Strasbourg – France were to be asked to serve as an “umbrella” body for this group of greatly worried radio astronomers. Hans Kahlmann brought this desire to the attention of the ESF at Strasbourg. After some discussions it was agreed in 1988 that a Committee on Radio Astronomy Frequencies of the European Science Foundation, CRAF, would be founded as an ESF expert committee. CRAF would be made up of representatives of the major radio astronomical observatories in Europe. Hans Kahlmann was appointed as the first CRAF chairman and Titus Spoelstra as its first secretary.

According to its Charter and Terms of Reference, the mission of CRAF is:

(a) to keep the frequency bands used for radio astronomical observations free from interference.
(b) to argue the scientific needs of radio astronomy for continued access to and availability of the radio spectrum for radio astronomy within the European arena.
(c) to support related science communities in their needs of interference-free radio frequency bands for passive use.

3. An established committee

CRAF attempts to co-ordinate the representations made to the various national and supranational radio regulatory bodies within Europe for the protection of the Radio Astronomy Service. It operates both at an administrative and at a technical level, so that it is for instance also concerned with setting up programs of interference monitoring and it seeks to develop technical means for the protection of radio astronomical observations.
It has an educational role in making other, particularly active radio spectrum users, aware of the sensitivity and consequent need for protection of radio astronomy frequencies. To serve this function and following a suggestion of Thormod Boe (director of ERO at that time), CRAF published its “Handbook for Frequency Management” and its “Handbook for Radio Astronomy” (at 3rd edition), which are intended to make National Regulatory Administrations, System Designers and Spectrum Managers widely aware of the radio frequency case of radio astronomy.
Furthermore, CRAF regularly publishes a Newsletter. It also organizes workshops on technical spectrum management issues.

CRAF is probably best known world-wide through its website, nowadays one of the biggest free resource for spectrum management. It is used frequently as a reference in many of the regulatory deliverables. Initially, the website was hosted by ASTRON. But, in March 2005 Laurentiu Alexe came up with the idea of having a formal internet domain for CRAF. Because the registration process for the .eu internet domain started only in the Spring of 2006, this idea finally materialised on 11th November 2006; www.craf.eu was born!

Since January 1, 1997, CRAF has employed a full time pan-European radio astronomy Spectrum Manager –  The ‘CRAF Frequency Manager’. Approaching retirement, in 2005 Titus Spoelstra handed over the post to Laurentiu Alexe, who joined CRAF in 2005 and served in this position until 1st September 2010. Harry Smith, of Oxford Astrophysics in the UK replaced Laurentiu as Frequency Manager in late 2010 until May 2013. From March 2014 to February 2019 Talayeh Hezareh, of the Max-Planck Institut für Radio Astronomie in Bonn, Germany, was CRAF’s Frequency Manager. Its current CRAF’s Frequency Manager is Dr Waleed Madkour – The Netherlands (2020-    )

Having initially met twice yearly, since 2012 CRAF now meets once each year at one of the European radio astronomy observatories or at the ESF premises in Strasbourg. October 2015 saw CRAF’s 58th meeting. The CRAF chairmanship is ensured through rotation by the funding member institutes. Over the years the chairmanship has been held by: Dr Hans Kahlman – The Netherlands (1988-1995), Prof. Jim Cohen – UK (1995-2000), Dr Wim van Driel – France (2001-2003), Dr Roberto Ambrosini – Italy (2003-2008), Dr Axel Jessner – Germany (2008-2013), Dr Hans van der Marel – The Netherlands (2013-2015), Dr Wim van Driel – France (2016-2018) and Dr Michael Lindqvist – Sweden (2019-2021). Its current Chairman is Dr Benjamin Winkel – Germany (2021-    ).

CRAF is Sector Member of the Radiocommunication Sector of International Telecommunications Union and it has a formal observer status within the CEPT.

Committee on Radio Astronomy Frequencies