CRAF Newsletter 1999/4

CRAF Newsletter 1999/4

October 1999


The European Science Foundation is an association of its 65 member research councils and academies in 22 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.

On behalf of European radio astronomers, the ESF Committee on Radio Astronomy Frequencies, CRAF, coordinates activities to keep the frequency bands used by radio astronomers free from interference.


Contents


1. Chairman's Corner

Readers of this Newsletter will know full well that radio astronomers have been concerned for many years at the levels of unwanted emissions from satellites, particularly those operating in frequency bands close to the passive bands that we use. The formation of Task Group 1/3 and then its successor TG1/5 seemed to offer us a chance to improve the regulatory situation. Yet how slow the progress has been and how small the positive achievements.

One difficulty faced by both Task Groups has been the lack of technical information from the satellite community on practical levels of unwanted emissions that can be achieved with modern technology. This information is needed if realistic limits are to be set in the Radio Regulations. Until recently the Task Groups had only been given limits which were so old they predated ITU Recommendation 66.

It was therefore a welcome change when the latest meeting of TG1/5 (reported in section 6 of this Newsletter) was presented with an information paper from Eutelsat concerning their recently launched W-series satellites. The specification on unwanted emissions from the new Eutelsat satellites was drawn up based on the radio astronomy protection criteria of Recommendation ITU-R RA.769-1. Although we have often been told that the numbers in Recommendation ITU-R RA.769-1 cannot be met by practical satellite systems, the good news is that the limits are not hopelessly unrealistic after all. They can be achieved by some operators using modern technology.

In view of this, CRAF is making its first ever Green Award. The award, for neighbourly use of the radio spectrum, goes to Eutelsat. It is my hope that CRAF will be able to make many more Green Awards in future years.

R. J. Cohen
Jodrell Bank Observatory


2. CRAF meeting 28 (6-7 September 1999)

The 28th CRAF meeting was held at the Sidney Sussex College in Cambridge, England. The main items discussed during the meeting concerned the evaluation of the negotiations between CRAF and Iridium LLC towards an agreement for the period 1 May 1999 - 1 January 2006, the work in CEPT project teams, the CEPT Detailed Spectrum Investigation Phase III (862-3400 MHz), coordination with MSS Mobile Earth Stations (e.g. GLOBALSTAR) and the preparations for the WRC2000.

  • CRAF-Iridium LLC negotiations: With some minor improvements, a document evaluating the ESF-Iridium LLC agreement for the period 1 May 1999 - 1 January 2006 by the CRAF negotiation team was adopted by the meeting. This document also contains elements of guidance for possible future negotiation rounds. CRAF will soon start with the actions required by the agreement. Up until now, Iridium LLC has not shown any progress on any action which it is required to do by the agreement.

  • CEPT project teams: As usual, CRAF participates actively in CEPT project teams. The FM-PT33 work on the issue of allocation of frequencies above 71 GHz in preparation of WRC2000 has ended and will be completed by ERC CPG PT3 which works on WRC2000 issues. (CRAF also participates in this ERC project team). FM-PT34 working on high density fixed(-satellite) service applications discussed some bands relevant for radio astronomy: 40.5-42.5 GHz for which no conclusion could be reached and the ERC CPG will decide on a European Common Proposal for WRC2000; and the frequency ranges at ~22 GHz and ~11 GHz for which more work has to be done to safeguard the protection of radio astronomy in adjacent bands.
    Project team SE-PT28 continued the discussion of the impact on radio astronomy of aeronautical earth stations, AESs, on board of airplanes. ETSI is developing a European standard for AES. In this process Motorola and Inmarsat have different opinions. As usual, Motorola provides only limited background and information which hampers the progress. Following an action item, CRAF and Inmarsat started bi-lateral discussions on the issue. These will be completed and reported to SE28 early 2000.

  • Preparations for WRC-2000: The preparations for the World Radiocommunication Conferences are already in full swing. The CRAF and IUCAF positions are fully consistent with each other.

  • DSI-III: CRAF explained its perspective for radio astronomical frequency requirements in the frequency range 862-3400 MHz for the next 10 years to the CEPT. This opinion should be reflected in the conclusions in the DSI-III process, which are expected to be completed early 2000. CRAF is concerned that not all radio astronomy frequency usage is accurately reported in the ERO frequency usage information table, based on the inputs from administrations.

  • MES coordination: In several countries administrations request radio astronomy stations to discuss the coordination between radio astronomy and MSS MESs. CRAF will prepare a position document on the coordination between MESs and radio astronomy stations in Europe. This document which shows the CRAF view on the issue is the CRAF guideline for the discussions with the national administrations.

  • other activities: the CRAF website has been extended with several new facilities and options, such as query facilities for the catalogued documentation in the CRAF clearing house, tools to investigate the EMI and spectrum occupancy databases.


    3. Channel 38 and DVB-T

    TV channel 38 covers the frequency band 608-614 MHz which is intensively used by radio astronomy in Europe is again under pressure. In various European countries the development of digital video broadcasting (terrestrial), DVB-T, is implemented following the Chester 1997 Multilateral Coordination Agreement on DVB-T. In Belgium, transmitters are planned for operations in channel 38 in Liège, Brussels and Charleroi. In France, similar transmitters are considered for Lille and Rouen. Other countries, such as Germany, Norway and the UK are also planning DVB-T use of channel 38.

    CRAF members discussed the impact of this development on radio astronomy operations in this frequency band. CRAF brought its concerns explicitly to the attention of the Belgian and French authorities, because the transmitter characteristics and their locations are such that not only radio astronomy in Belgium and France is affected but also in neighbouring countries, i.e. Germany and the Netherlands.

    At this moment, the Belgian authorities have not reacted did not react to the CRAF concerns. The French administration explained mid-September 1999 that the coordination requests for the implementation of DVB-T in channel 38 in France to the administrations of neighbouring countries have been withdrawn. However, the French administration is keeping the possibility open to use channel 38 in France for smaller 'filler-'transmitters.

    CRAF appreciates the French position and it keeps monitoring the developments to safeguard European radio astronomy operations in the band 608-614 MHz.


    4. Detailed Spectrum Investigation - Phase III

    The CEPT launched its Detailed Spectrum Investigation (DSI) Phase III in May 1998. This investigation is covering the frequency designations and usages in the frequency range 862-3400 MHz. The CEPT ERO invites contributions and ideas on how the spectrum within this frequency range should be managed during the next 10-15 years. The first DSI-III workshop was held 15 July 1998, and discussed the market scenarios for different radiocommunication services, based on input provided by industry, operators, users and organisations. The CRAF view is explained in a chapter in the ERO document on Market scenarios and views on the development of radio services within the DSI range 862-3400 MHz.

    EISCAT provided input to the DSI-III process at the 2nd workshop, which was held on February 10th, 1999, and which discussed the reactions to the ERO market scenario document.

    Since that meeting the ERO has produced a Strategic National Frequency Plans document from contributions of CEPT administrations. ERO has also produced a document with preliminary conclusions and a compilation of contributions from industry, operators, users and organisations. The CRAF DSI-III position is also published in this document.

    The final DSI-III results will be presented and discussed in the next DSI-III workshop on February 22nd, 2000.

    CRAF is actively participating in this process.


    5. XXVIth URSI General Assembly 1999

    During August 13-21, 1999, the XXVIth URSI General Assembly took place in Toronto, Canada. According to the different program elements and previous announcements, this conference would pay attention to the issue of protection of radio frequencies needed for scientific research. However, in practice, little real discussion could take place between scientific users of the radio frequency spectrum and non-scientific users of this spectrum by which the pressure on the radio spectrum is generated. The program of the General Assembly showed that different sessions addressing aspects of this issue were scheduled in parallel so that it was impossible for interested people to participate in both.
    Furthermore, the program of the General Assembly did not have fixed time slots for the inter-union committees such as IUCAF and SCOSTEP. In this General Assembly they hardly got the right attention, such as by clear central announcements. One may object that these bodies could make themselves more visible, but that is only a small part of the story: it is highly desirable that time-slots are scheduled for these committees at future General Assemblies.
    A third observation was that the tutorial lecture on spectrum congestion was the very last presentation of the whole conference, like a sermon before the blessing. Surely such key presentations should be scheduled at the very central moments in the conference.

    IUCAF had an interwoven session which because of scheduling conflicts with other assembly activities did not receive much attention. Dr.W.A.Baan as past-chairman summarized the work of IUCAF and its related regional organizations during the last 3 years and he gave an introduction to the WRC2000 agenda items relevant for radio astronomy.

    In the Commission J business session, one of the issues dealt with 'mitigation techniques'. Dr.W.A.Baan and the CRAF frequency manager T.A.Th.Spoelstra explained that one must be extremely careful with this issue: i.e. not to give active users arguments that they can raise their transmission powers by e.g. 10 dB. If necessary one could speak of mitigation factors but then only for the case that one needs to do observations outside allocated frequency bands. On the other hand radio astronomers must know that they have to design and build their equipment to avoid any interference impact (see ITU-R article S29), which implies that when one explains that one is addressing the mitigation issue, one can only be convincing if one can show that in the past one's work was excellent and state-of-the-art already: otherwise, active users will not take scientists seriously in instrumental issues.

    The URSI installed a new commission, the Scientific Committee on Telecommunications, SCT, under chairmanship of P. Delonge to improve the relation between URSI and ITU, to work on the preparation of COMMSPHERE conferences and to develop technical study questions. Dr.W.A.Baan is also in this new committee. Spoelstra raised the question about the working-relationship between this new committee and IUCAF and the danger of adding yet another kind of organsation to work on frequency management issues. Several decades ago, IUCAF had been given the mandate to coordinate the relation between URSI and ITU.

    Dwingeloo - T.A.Th.Spoelstra


    6. TG1/5 Fifth Meeting, Assen, the Netherlands

    The fifth meeting of TG1/5 was held in conjunction with Study Group 1, on 16-24th August 1999, in Assen, the Neterlands. A total of 150 delegates were present at one or both meetings. Radio astronomy had 7 representatives in all, but only 4 were present for the whole of the TG1/5 meeting. An excursion to Westerbork and Dwingeloo on 23rd August gave radio astronomy a good opportunity to raise its profile.

    TG1/5 concluded its revision of Recommendation ITU-R SM.329, and the revised version, SM.329-7, was approved by Study Group 1 plenary with only minor editorial improvements. The spurious emission limits for space services are no longer listed as design objectives, although they are still referenced to 4 kHz bandwidth.

    Annex 3 of Recommendation ITU-R SM.329-7 lists threshold levels of interference for the radio astronomy service. The limits are taken from Recommendation ITU-R RA.769-1, which does not explicitly list interference levels for all radio astronomy bands. As a consequence, there are still no limits specified for eight radio astronomy bands which have a primary allocation via Footnote S5.555. TG1/5 will incorporate the remaining frequency bands when and if they are incorporated directly in Recommendation ITU-R RA. 769-1. It should be noted that the first of the bands in question happens to be the CS band 48.94-49.04 GHz. High altitude platforms (HAPs) are planned to transmit in nearby frequency bands. If radio astronomers want the CS band to be protected from the HAPs spurious emissions then something other than Recommendation ITU-R SM.329-7 will be needed.

    TG1/5 is preparing a draft new recommendation on interference into adjacent bands (so-called out of allocated band or OAB emissions). The work was finished in Drafting Group 4, and approved by TG1/5, but it was not passed over to Study Group 1 for their approval at this meeting, to give the US administration time to consider the implications further. The OAB concept is one in which radio astronomers have a long- standing interest. Its work being completed, Drafting Group 4 was disbanded, as were Drafting Group 5 (329-7) and Drafting Group 2 (intermodulation).

    Drafting Group 6 continued to work on Preliminary Draft New Recommendations (PDNRs) to protect safety services and passive services from unwanted emissions. Klaus Ruf chaired DG6, the safety services subgroup was chaired by Ted Jones (Inmarsat) and the passive services subgroup was chaired by Jim Cohen. Progress on safety services, and on passive services other than radio astronomy, was limited by the absence of representatives from those communities and a shortage of relevant input papers. Nevertheless both the PDNRs were improved during the meeting. However it is imperative that timely inputs are made before the sixth meeting of TG1/5. (Unfortunately WP7D will not meet again until after the next meeting of TG1/5).

    Within the passive services drafting group an interim report on the progress of the band-by-band studies was produced. This working document gives the current situation, often incomplete, regarding the studies being carried out by various working parties each with their own independent meeting schedules. There was unexplained opposition to the production of this report, from a small number of participants from the space services community.

    Three input documents occupied much of the time of the passive services drafting group. There were inputs from Eutelsat and from the French Administration (originating from Alcatel). Eutelsat created a minor furore by announcing that its recently launched W series satellites meet a spurious emission specification based on the radio astronomy interference thresholds of Recommendation ITU-R RA.769-1. There were strong attempts to bury this input from Eutelsat, that is, to simply note it as an information document, but after much hard talk the document was sent in a liason statement to Working Party 4A for their comments, and a digest of the document was retained in the interim report. Working Party 4A has yet to provide any information on spurious emission limits that can be met by current satellites. There was no information sent to TG1/3 during its entire lifetime, and no input yet to TG1/5. The Eutelsat document should therefore have been particularly welcome as an example of practical limits on spurious emissions from satellites. But not welcome in all quarters, it seems. The two French documents also aroused strong opposition for reasons that were not openly stated, but again the essential elements were retained in the interim report, and one document was sent to WP4A and to WP7D for comments. The document uses the concept of equivalent power flux density (epfd) for a constellation of satellites and proposes a methodology for studying the statistics of interference to radio astronomy. The methodology includes coordination of the main beam, which may have caused concern in some quarters. Radio astronomers will need to study this methodology carefully.

    Events in Assen did little to bring the radio astronomy and the satellite communities closer together. In fact I observed a growing mutual distrust between these two groups, which will not benefit either in the long run, I believe. I hope the situation will improve before the next meeting of TG1/5, which will be in Bangalore, India, 6-14th January 2000.

    Further information on the Assen meeting of TG1/5 can be found in the IUCAF document 448.

    R. J. Cohen
    Jodrell Bank Observatory


    7. Abbreviations used in this Newsletter

    AES = Aeronautical Earth Stations
    CEPT = Conference of European Post and Telecommunication administrations
    CPG = Conference Preparatory Group (CEPT
    CRAF = Committee on Radio Astronomy Frequencies (ESF)
    DG = Drafting Group
    DSI = Detailed Spectrum Investigation (CEPT)
    DVB-T = Terrestial Digital Video Bradcast
    EISCAT = European Incoherent Scatter Scientific Association
    EMI = Electromagnetic Interference
    ERC = European Radiocommunications Committee (CEPT)
    ERO = European Radiocommunication Office (CEPT)
    ESF = European Science Foundation
    ETSI = European Telecommunication Standards Institute
    FM = ERC Working Group Frequency Management (CEPT)
    HAPs = High Altitude Platforms
    ITU = International Telecommunication Union
    ITU-R = ITU Radiocommunication Sector
    IUCAF = Scientific Committee on the Allocation of Frquencies for Radio Astronomy and Space Science (UNESCO)
    MES = Mobile Eart Station>br> MSS = Mobile-Satellite Service
    OAB = Out of Allocated Band
    PNDR = Preliminary Draft New Recommendation (ITU-R)
    PT = Project Team
    SCOSTEP = Scientific Committee on Solar Terrestial Physics
    SCT = Scientific Committee on Telecommunications (URSI)
    SE = ERC Working Group on Spectrum Engineering (CEPT)
    SG = Study Group (ITU-R)
    TG = Task Group (ITU)
    UNESCO = United Nations Education, Scientific and Cultural Organization
    URSI = Union Radio Scientifique International
    WP = Working Party (ITU-R)
    WRC = World Radiocommunication Conference (ITU-R)


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    Last modified: October 26, 1999