CRAF Newsletter 1995/1
The European Science Foundation is an association of its 50 member research councils and acedemies in 18 countries. The ESF brings European scientists together to work on
topics of common concern, to co-ordinate the use of expensive facilities, and to discover and define new endeavors that will benefit from a co-operative approach
The scientific work sponsored by ESF includes basic research in the natural sciences, the medical and biosciences, the humanities and the social sciences.
The ESF links scholarship and research supported by its members and adds value by cooperation across national frontiers. Through its function as coordinator, and also by holding workshops and conferences and by enabling researchers to visit and study in laboratories throughout Europe, the ESF works for the advancement of European science.
Introduction to the ESF - Committee on Radio Astronomy Frequencies
On behalf of European radio astronomers concerned with interference in the frequency bands used
for radio astronomy, the European Science Foundation had formed a Committee on Radio
Astronomy Frequencies (CRAF). The task of the Committee is to coordinate activities to keep the
frequency bands used by radio astronomers free from interference. It attempts to fulfil this task by:
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.
- Co-ordinating the radioastronomy case in Europe in discussions with the major public and private
- 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.
1. CRAF membership
The members of CRAF are appointed by the ESF Executive Council for a three year period, after
consultation through the appropriate channels. They are drawn among experts active in the field of
frequency management at radio-astronomical observatories in Europe complemented by ESF
At present the members representing their countries are from the Observatoire
Royal de Belgique (Belgium), Ondrejov Astronomical Observatory (Czechia),
Nançay Observatory (France),
Max-Planck Institut für Radioastronomie (Germany),
the Istituto di Radioastronomia C.N.R. (Italy),
Ventspils International Radio Astronomy Center (Latvia),
the Netherlands Foundation for Research in Astronomy (the Netherlands),
Torun Radio Astronomy Observatory (Poland),
the Observatório Astronómico, Prof.Manuel de Barros, Universidade
do Porto (Portugal), Scientific Council on Radio Astronomy of the Russian
Academy of Sciences (Russia), Centro Astronomico Nacional (Spain), Onsala
Space Observatory (Sweden), Institute of Astronomy, ETH Zentrum (Switzerland),
Marmara Research Centre (Turkey) and the Nuffield
Radio Astronomy Laboratories (United Kingdom), and from the European
Space Agency (ESA),
the European Incoherent Scatter Scientific Association (EISCAT) (Finland,
France, Germany, Norway, Sweden, United Kingdom), the Institut de
Radio Astronomie Millimétrique (IRAM) (France, Germany, Spain).
The European Science Foundation (ESF) is represented by a liaison officer.
2. Management and operation of the committee
The Committee is self-managed from its Office at the Netherlands Foundation for
Research in Astronomy: Dr.R.J.Cohen is the Chairman and Dr.T.A.Th.Spoelstra
The committee meets usually at least twice each year.
The address of the CRAF clearing house is: Dr.T.A.Th.Spoelstra,
Netherlands Foundation for Research in Astronomy, Postbus 2, 7990 AA Dwingeloo,
The Netherlands, tel.: (+31)521-595100, telefax (+31)521-597332,
3. Major activities
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
- The members of CRAF communicate with the same message to their national Administrations.
- The Committee communicated with the British Department of Trade and Industry (DTI)
concerning the possible use of frequency channel 38 for TV. The resulting decision of the British
department was the allocation of channels 35 and 37 to TV and to allow channel 38 to be kept free
for radio astronomy.
- 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.
- Special attention has been given to frequency allocation and management problems in Italy, which
have led to a less than desirable electromagnetic environment for radio astronomical work. The
Committee has communicated with the appropriate representatives of the Italian administration and
NATO to stimulate an active search for solutions in favour of radio astronomical research in Italy.
The result is that in specific cases (such as interference within the 21 cm band by military radar on
Sicily) a search for such solutions has been started.
- The Committee stimulated already initiated NATO-CCMS activities to investigate the possibilities
of a more alert administrative control of frequency allocation matters, including international
judicial support. CRAF was informed about good perspectives for the acceptance of the proposed
- The well-prepared and coordinated activities of the CRAF members who participated in the
WARC 1992 (as members of the IUCAF delegation or a national delegation) contributed in no small
measure to the favourable outcome for the Radio Astronomy Service, RAS. One favourable result
of WARC-92 has been the upgrade of the status of the Radio Astronomy Service in the band
1610.6-1613.8 MHz from secondary by footnote to co-primary world-wide in the table. Another
favourable result was that this WARC has recommended a CCIR study, as a matter of urgency, on
the spurious emissions from space transmissions in all bands, with a view to specifying spurious and
out-of-band emission limits in the Radio Regulations, for the protection of the Radio Astronomy
Service and other passive services, at the next competent World Radio Conference.
- CRAF communicated with the CEPT Radiocommunications Office in Copenhagen about the
Detailed Spectrum Investigation (DSI) performed by this bureau in preparation of a European
frequency table by the year 2008. It observes that the CRAF views have been integrated in the DSI -
phase I and phase II.
- CRAF participated in the CEPT SE17 PT on "the compatibility between MSS uplink and other
radio systems in the 1610-1625.5 MHz band". Basically the question is how the existing services
in this band and the Mobile Satellite Service (MSS) are able to operate together in a radio-quiet way.
Sharing of MSS with the RAS turned out to be very difficult. For sharing of MSS with radio
astronomy coordination distances of the order of 250 km are required.
- CRAF participated in the organization of the scientific program of the Wroclaw EMC Symposium
1994 (28 June - 1 July 1994). It organized a session on "Interference Effects in Radio Astronomy".
CRAF intends to participate more in these bi-annual conferences in future.
3.1 Outstanding problems
3.1.1. Acute problems
Very important are the bi-annual ITU World Radio Conferences (WRCs), which started in 1993.
The agendas are usually known 2-4 years in advance. However, this new set of meetings related
with the new ITU structure requires a continuous alterness to the developments which may have
implications for the future of the Radio Astronomy Service.
The Committee paid special attention 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 have had to abandon the
attempts together with the hope of ever observing the sky in this frequency band.
Other important items the Committee had discussed are:
- the increased interference in the 18 cm band (OH emission) by Mobile Satellite System
- the increased threat for the 18 cm band by the Radio Determination Satellite Service, RDSS, on
which CRAF explained its views on a proposal of the French LOCSTAR project for blanking
radiotelescopes when a detectable LOCSTAR transmission occurs (CRAF-90-2A)
- the Belgian MLMS satellite for space-to-Earth transmissions between 400.15 MHz and 401 MHz
using spread spectrum spectrum, direct sequence. CRAF fears that harmful interference will be
experienced in the radio astronomy bands 322-328.6 MHz and 406-410 MHz. Via the Dutch
administration CRAF expressed its worries to the Belgian administration and the ITU
Radiocommunications Bureau, Space Service Department.
3.1.2. Long term problems
Long term problems are in particular those problems which today and very probably in the near
future have not been fully studied by the ITU Radiocommunications Bureau and which will cause
severely harmful interference when they come into effect. The indication "long term" indicates that
certainly in the next few years an adequate solution is very unlikely and methods and techniques
have to be found in the radio astronomical community to cope with them.
Urgent problems are:
- introduction and application of new modulation techniques: in particular systems using band-
spreading are a potential source of harmful interference. In this band-spreading technique
bandwidths of several hundreds MHz are used, while the transmitted power is widely spread over
this band and may be just under the current ITU-R recommendations. For security reasons generally
encryption codes are added to the transmitted signal. For radio astronomy this means that when the
wide band spectrum covers a radio astronomy band - no matter that it be at a very low level - the
"sky background" increases and it is no longer be possible to study weak features (even after long
- time-sharing: proposal are made that the radio astronomy service should accept frequency
allocations with the condition that only a fraction of each second of Universal Time be used for
passive frequency use (i.e. radio astronomical observations) which is left over after an active
application has already taken its part. This procedure may hold for some coordination distance
around an observatory. So far many different problems related to sharing have not been considered
by the ITU-R, but nevertheless radio astronomy has already to investigate methods to cope with any
- pricing the spectrum is becoming an important question and the developments have to be
monitored very carefully. The implementation of this policy may have serious impact on the budgets
and operations of observatories. The lack of coordination between the different national
administrations within Europe makes this topic rather confused at present.
4. Relations with other bodies
- CEPT: CRAF has been recognized by the Conférence Européenne des Postes et des
Télecommunications (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 (see
- CORF: The Commission on Radio Frequencies (CORF) of the US National Research
Council coordinates in the USA activities to keep the frequency bands used by radio
astronomers free from interference. CRAF and CORF cooperate intensively.
Dr.T.A.Th.Spoelstra is the liaison of CRAF to CORF.
- EC: The European Community (EC) becomes increasingly active in the field of frequency
allocation/management matters. Since its interest is primarily not scientific, it may support
proposals which create (potential) harmful interference for passive services such as radio
astronomy. In communicating with this organization CRAF attempts to serve the radio
astronomy service by making its views known, by making suggestions for improvement and
by opposing proposals which create harmful interference to radio astronomy. (At present
these contacts are starting).
- ERO: CRAF has good contacts with the CEPT European Radiocommunications Office
(ERO), in Copenhagen. Recently it communicated with this office concerning the
radio frequencies used by the different radio astronomical observatories in Europe.
- ETSI: CRAF is working to establish good communications with the European
Telecommunications Standards Institute (ETSI).
- ITU-R: Through its members CRAF has intensive contacts with the technical committees of
the International Telecommunication Union (ITU), the ITU Radiocommunications
- IUCAF: The Inter-Union-Commission on the Allocation of Freqencies (IUCAF) is a
commission of the International Council of Scientific Unions (ICSU). Its parent
organisations are the International Union of Radio Science (URSI), the International
Astronomical Union (IAU) and the Committee on Space Research (COSPAR).
IUCAF deals with matters of frequency allocation, interference and protection on
behalf of the radio astronomy service on a world-wide basis. CRAF acts in support
of IUCAF and provides IUCAF with all relevant regional European information. The
CRAF chairman is an IUCAF member.
- NATO: CRAF participates actively in a NATO study in the context of the Commission on
the Challenges of Modern Society (CCMS) as already described above (section 3.2).
It is CRAF's experience that the new developments after the WARC 1992 require that it is more than
ever necessary that the radio astronomical community speaks with one voice on interference and
frequency management problems in communication with administrations and other relevant bodies.
In its work CRAF noted that taking into account the characteristics of the work in preparation of the
WARC 1992, which deals with many discussion at administration- and frequency-management-level, and also that after this meeting due to the nature of the problems, it is highly desirable that
a professional spectrum-manager is available for this work. A position like this exists already for
several years in the United States (a spectrum manager as an employee of the National Science
Foundation). Also bodies like space agencies have their spectrum management offices. The
experience is that this professionalization is urgently needed in CRAF context as well.
To have the radio astronomy voice heard, CRAF needs to continue with an active policy to try to
make contact and to communicate with bodies involved in matters of frequency-management.
On behalf of CRAF, the European Science Foundation published a Handbook for Radio Astronomy
in 1995. The CRAF Newsletter will be published twice every year (usually shortly after the CRAF
meetings). It is published by the European Science Foundation. The CRAF Newsletter will also be
made available through the World-Wide Web.
7. CRAF memberlist
R.J.Cohen, Nuffield Radio Astronomy Laboratories, Jodrell Bank, Macclesfield,
Cheshire SK11 9DL, England
T.A.Th.Spoelstra, Netherlands Foundation for Radio Astronomy, P.O.Box 2, 7990 AA Dwingeloo, The Netherlands
R.Bachiller, Centro Astronomico Nacional, Apartado 1143, E-28800 Alcala de
A.O.Benz, Radio Astronomy Group, Institute of Astronomy, ETH
Zentrum, CH-8092 Zürich, Switzerland
E.Bervalds, Latvian Academy of Sciences, 19 Turgeneva Street, LV-1524 Riga,
G.F.Block, ESA, Frequency Management Office, Directorate of
Telecommunications, 8-10 rue Mario-Nikis, F 75738 Paris Cedex, France
P.Cugnon, Observatoire Royal de Belgique, Ave Circulaire 3, B-1180
B.Darchy, Nançay Observatory, Station de Radioastronomie,
F 18330 Neuvy/Barangeon, France
B.A.Doubinski, Scientific Secretary, Scientific Council on Radio Astronomy of the Russian
Academy of Sciences, Moscow, centre, GSP-3, Marx Avenue 18, Russia
S.Gorgolewski, Toru Radio Astronomy Observatory, Katedra Radioastronomii Uniwersytet
Mikolaja Kopernika, ul. Chopina 12/18, 87-100 Torun, Poland
D.Morris, Institut de Radio Astronomie Millimétrique, IRAM, Headquarters, Domaine Universitaire
de Grenoble, F-38406 St.Martin d'Hères Cedex, France
M.E.Özel, Marmara Research Centre, Space Sciences Department, P.O.Box 21, 41470 Gebze-Kocaeli, Turkey
J.E.B.Ponsonby, Nuffield Radio Astronomy Laboratories, Jodrell Bank, Macclesfield, Cheshire
SK11 9DL, England
W.Reich, Max-Planck Institut für Radio Astronomie, Radioobservatorium Effelsberg, D-53902 Bad
Münstereifel, Bundesrepublik Deutschland.
K.Ruf, Max-Planck Institut für Radio Astronomie, Auf dem Hügel 69, D-53121 Bonn,
A.A.Sanches de Magalhaes, Observatório Astronómico, Prof.Manuel de Barros, Universidade do
Porto, Monte da Virgem, 4400 Vila Nova de Gaia, Portugal
A.Tlamicha, Astronomical Observatory, 25165 Ondrejov, Czech Republic
G.Tomassetti, Istituto di Radioastronomia C.N.R., Via Gobetti 101, 40129 Bologna, Italy
A.P.van Eyken, EISCAT Scientific Association, Ramfjordmoen, N-9027 Ramfjordbotn, Norway
A.Winnberg, Onsala Space Observatory, S 43900 Onsala, Sweden
ESF liaison officer:
H.U.Karow, European Science Foundation, 1 quai Lezay-Marnésia, F 67080 Strasbourg Cedex, France
European Science Foundation:
1 quai Lezay-Marnésia, F 67080 Strasbourg Cedex, France, tel.: (+33)184.108.40.206, telefax