CRAF Newsletter 1999/1

February 1999


The European Science Foundation is an association of its 62 member research councils and academies in 21 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. Chairmans' Corner

As we prepare to enter the new millenium it is timely to reflect on the forthcoming World Radio Conference. WRC-2000 will bring radio astronomy onto the ITU stage and into the limelight as never before. The agenda contains many items which will affect the future of our science. Some are very explicit, for example possible new allocations above 71 GHz; others are hidden in the agenda, for example the agenda item 1.2 on spurious emissions, which will allow WRC-2000 to set the first regulatory limits on spurious emissions from spacecraft. These and other WRC-2000 issues for radio astronomy are discussed in several of the following articles in this Newsletter.

The problem of unwanted emissions from spacecraft was closely associated with the founding of CRAF in 1987, during the period of severe GLONASS interference at 1612 MHz. The GLONASS situation is now steadily improving, thanks to the step-by-step plan agreed between IUCAF and the GLONASS Administration in 1993. Six years on we (ESF-CRAF) are now negotiating with Iridium over possible interference into the same 1612 MHz band. It is a band widely used in Europe and elsewhere to observe a spectral line of the hydroxyl (OH) radical.

Iridium's own advertising talks of Freedom to Communicate. Anytime. Anywhere. It is a fundamental aim of all radio services, to coexist peacefully in the radio spectrum. Translated into radio astronomy terminology it would read Freedom to Observe. Anytime. Anywhere. But it seems that the first generation of Iridium satellites will place restrictions on when and when we can observe the 1612 MHz OH band, even though the allocation to the Iridium downlink is to a different, not even adjacent, frequency band. The Framework Agreement agreed last July gives us at least a date by which these restrictions will disappear (see last Newsletter, 1998, Issue 3). Meanwhile we have until the middle of 1999 to reach an agreement in Europe on how the radio astronomy and mobile satellite services (Iridium) can make best use of the sharing opportunities in the intervening years, up to 2006, without either party dictating the terms and conditions under which the other should operate. An agreement on how to properly share the radio spectrum. We wish the negotiating terms every success.

Looking to the future, our community needs to face the fact that although awareness of our problems is growing within ITU, the full solutions to these problems are some way off. Things are moving in the right direction, but very slowly. For example the limits on spurious emissions from spacecraft which are likely to be proposed to WRC-2000 would not protect us from current satellites (Astra, GLONASS, Iridium) to the levels of ITU-R Rec. 769-1. In fact they would fall short by many tens of dB. It is better to have some limits than no limits at all, of course! But we hope it will not take a millenium to convince our national adminstrations that the Rec. 769-1 limits really are needed to protect radio astronomy, and that modern technology will allow future generations of satellites to meet the corresponding limits on their unwanted emissions.

Jodrell Bank - R.J.Cohen


2. Report of 26th CRAF meeting (8-9 October 1998)

The 26th CRAF meeting was held at the European Science Foundation office in Strasbourg. The main items discussed during the meeting concerned the evaluation of the ESF-Iridium LLC Framework Agreement, the progress of the licensing of the IridiumęSystem in Europe, the work in CEPT project teams, the preparations for the WRC-2000.

* ESF-IridiumLLC Framework Agreement:

On August 11th, the European Science Foundation (on behalf of CRAF) and Iridium LLC ratified a Framework Agreement between both parties which was achieved under the guidance and in cooperation with the CEPT Milestone Review Committee of the ERC, MRC. This agreement is a formalization of the MRC Recommendation 4 (adopted on March 27, 1998) and is used by European administrations in the licensing process for the Iridium system. The principal results are:

  • before 1 March 1999 the out-of-band emissions from the transmissions of the IridiumęSystem shall be below the levels of detrimental interference given in ITU-R Recommendation RA769-1.
  • after 1 January 2006 the out-of-band emissions from the transmissions of the IridiumęSystem shall be below the levels of detrimental interference given in ITU-R Recommendation RA769-1.
  • between 1 March 1999 and 1 January 2006 an agreement between CRAF and Iridium LLC should be reached on the levels of detrimetal interference accepted for specific time windows.
    In addition, CRAF and Iridium LLC agreed to work cooperatively on a second agreement dealing with regulatory and technical details for the period between 1 March 1999 and 1 January 2006.

    The CRAF meeting supported the CRAF negotiation team by giving it full mandate to complete the negotiations with Iridium LLC.

    * CEPT project teams: As usual, CRAF participates actively in CEPT project teams. Much progress was achieved on the issue of allocation of frequencies above 71 GHz (FM-PT33) in preparation of WRC2000. The progress in FM-PT34 on high definition fixed(-satellite) service applications is rather slow because of a well-profiled position of Teledesic. For radio astronomy, the threat on the band 42.5-43.5 GHz from spaceborne transmissions in the band 40.5-42.5 GHz could not yet been resolved although CRAF made the radio astronomy requirements clear (also in SE-PT16 which addresses the technical aspects of this item).

    Progress in the study on spurious and out-of-band emissions (SE-PT21) is still very limited. The work in this project team is hampered by the position of some active users communities.

    * Preparations for WRC-2000: The preparations for the World Radiocommunication Conferences are already in full swing. Both regulatory conferences have great importance for the radio astronomy service. Much preparatory work is done in CEPT project teams, i.e. of the CEPT Working Group Frequency Management, WG FM. CRAF participates actively in this work and is working on a coherent European position for each of the WRC agenda items. The CRAF position is developed in close cooperation with IUCAF.

    CRAF also welcomed a new country in the group of countries participating in its work: Hungary became the 17th CRAF country.


    3. ITU-R activities: WP7D

    ITU-R Working Party 7D met in Geneva with 18 participants from 10 countries. Only one non-astronomer was present, which was a welcome change compared with previous meetings. The work of the meeting was greatly facilitated by the IUCAF meeting which had immediately preceded it, in Grenoble.

    WP7D considered 32 input documents which have been submitted before the meeting. In addition, one US document which arrived after the start of the meeting, because of hurricane Georges, was also considered.

    One of the major tasks of 7D is to produce a text for the ITU-R Conference Preparatory Meeting for the Agenda item 1.16 of the World Radiocommunication Conference planned for 2000, WRC2000, Passive Allocations above 71 GHz. A drafting group chaired by Dr.T.Gergeley (USA) worked on this and produced output text which was fed into the WRC-2000 Preparations Group of WP7D which met immediately afterwards (2-6 October 1998). Unfortunately the group was unable to produce in time a merged table of proposed allocations based on the US and CEPT inputs. However such a merged table will be appearing in the US and in PT33 on 22-23 October 1998, coordinated by Dr.T.Gergeley and Dr.W.A.Baan (IUCAF Chairman).

    WP7D is also lead a group on Agenda Item 1.4 and Resolutions 126(WRC97) and 128(WRC97) for WRC2000. Resolution 126 addresses the issue of the use of the frequency band 31.8-33.4 GHz for systems in the fixed service and Resolution 128 deals with Allocation to the Fixed Satellite Service (space-to-Earth) in the 41.5-42.5 GHz band and the protection of the Radio Astronomy Service, RAS, in the band 42.5-43.5 GHz. The Working Party worked on a text towards the WRC2000 Conference Preparatory Meeting; a work which will be carried over for completion in March 1999. The text was not mature enough to be fed to the WRC-2000 Preparations meeting this time.

    A second major drafting group chaired by RUF worked on the x% issue and was able to produce a preliminary draft new recommendation, PDNR. In summary it is recommended that in coordinating between the radio astronomy service and a single service or system, a figure of no more than 2% be applied as the percentage of time for which interference should exceed the levels given in ITU-R Recommendation RA.769-1, while a figure of no more than 5% be applied for the aggregate data loss acceptable to radio astronomy. This PDNR will be carried forward in the Report of the Chairman of ITU-R WP7D.

    Another PDNR was produced on the protection of the Lagrangian point L2 of the Earth-Moon system. This will also be carried forward in the Report of the Chairman of ITU-R WP7D. Comments from administrations would be very helpful. The feeling in WP7D was that this issue is close to being resolved and that the PDNR might be offered as a Draft New Recommendation next March.

    A drafting group chaired by Hans Kahlmann (Netherlands) dealt with liaison statements from ITU-R Task Group 1/5, TG1/5, and produced a series of liaison statements in reply. Hans is the official WP7D Rapporteur to TG1/5. Some of the liaison statements were also copied to WP4A and WP8D.

    Four further liaison statements were sent to WP8D, which deals with various satellite issues:

    The next meeting of WP7D (Radio Astronomy) will be held in Geneva, 3-12 March 1999. There will be an opportunity to visit the NRAO at Greenbank, where the new high-tech Greenbank Telescope is nearing completion.

    R. J. Cohen - Jodrell Bank


    4. CRAF and IUCAF in the ITU

    Since spring 1998, CRAF is sector member of the ITU Radiocommunication Sector. From then on, the radio astronomy community participates in ITU-R activities under the umbrella of IUCAF (which was already ITU-R sector member) and of CRAF. Given the European scope of the work of CRAF, it is obvious that CRAF's prime attention in ITU-R Sector work concerns the radio astronomy interests in Region 1 (in ITU-R terminology, Region 1 = Europe, Africa ...), with emphasis on Europe. On the basis of its mandate, IUCAF deals with global issues.

    Although from the scientific point of view the global nature of radio astronomy interests are guided by the universal laws of physics, various reasons of political, economic, project selection etc. lead to radio astronomy interests specific for Europe. CRAF especially follows attentively the development of CEPT opinions and activities.

    Given these consideration, CRAF sees its role in the ITU as a strengthening of the radio astronomy contribution to the work of the ITU-R. Wherever possible, CRAF and IUCAF have to work closely together, but in cases specific to Region 1, especially to Europe, CRAF's contribution is a constructive European articulation of the radio astronomy contribution to the ITU. An example of this is the preparation for the WRC2000 or CRAF input to ITU-R Study Groups and Working Parties.


    5. Preparations for WRC2000

    ITU-R World Radiocommunication Conferences are held every two years. The last conference was held in 1997, WRC97. The next conference will be held in 2000, WRC2000. The importance of this conference for radio astronomy is that the agenda contains a large number of issues of great to significant importance to radio astronomy. The agenda items which have most impact on radio astronomy are (in ITU-R/WRC jargon):

    CRAF participates actively in CEPT project teams which work towards preparation for WRC2000. On some issues some remarks can already be made:

    On agenda item 1.4, CRAF expressed the radio astronomy concerns on unwanted emissions spilling over from transmissions from space-to-Earth transmissions in the frequency bands just below 42.5 GHz into the band 42.5-43.5 GHz in which radio astronomy has a primary allocation. CRAF considers it technologically impossible to protect radio astronomy observations from unwanted emissions from space-to-Earth transmissions in a frequency band adjacent to a frequency band allocated to radio astronomy at these high frequencies. This radio astronomy position endorses the concerns on the protection of radio astronomy expressed during WRC97. This agenda item also addresses the opening of the band 31.8-33.4 GHz for high density fixed service applications (Resolution 126(WRC97)). These transmissions should take place in the uplink direction. CRAF participates in various studies to ensure that adequate coordination is ensured.

    On the issue of allocation of frequencies above 71 GHz (agenda item 1.16), CRAF contributed to the CEPT project team working on this. The cooperation with the remote sensing community for which these frequencies are also of great interest helped the project team very much to be able to develop a draft table which is currently subject to refinement. The CRAF position was intensively coordinated with IUCAF and ITU-R WP7D (as indicated in the report of WP7D).

    In parallel with the activities in IUCAF and radio astronomy communities elsewhere, CRAF works actively on a radio astronomy position for Region 1.'


    6. 1.4 GHz developments

    The band 1400-1427 MHz was the first passive band allocated to the radio astronomy service and it is still arguably the single most important band we have. The band contains the 1420-MHz transition of hydrogen, the most abundant element in the universe.

    Resolution 127 (WRC-97) calls for studies of the bands 1390-1400 MHz and 1427-1432 MHz for possible use as feeder uplinks and downlinks for non-GSO MSS systems with service links operating below 1 GHz. But for Hurricane Georges those studies might have been concluded by now.

    At its meeting in Geneva in September 1998, ITU-R Working Party 7D (radio astronomy) received a liaison statement from WP8D (MSS), dated 13 May 1998, and allegedly issued in response to a request from WP7D for technical information on the proposed feeder links near 1.4 GHz. The liaison statement contained results of a technical study purporting to show that the band 1427-1432 MHz would be suitable for the feeder downlink! This study was carried out in the USA on behalf of a satellite company. The details were sent from WP8D to WP7D for comment. The same information was also sent from WP8D to WP7C for comment, as the earth exploration satellite service (passive) also has an allocation in the band 1400-1427 MHz.

    WP7C received this liason statement and also a delayed contribution from the USA dealing with the very same issue. The delayed contribution was in fact a further instalment of the ongoing compatibility study being carried out in the USA. The delayed contribution was framed as an answer to the liaison statement from WP8D. WP7C assigned both documents to a one-man drafting group, who happened to be the author of the USA technical study, who by a strange coincidence was making his debut in ITU circles in Geneva. The drafting group reported favourably on the sharing study and the delayed USA contribution was accepted by WP7C with minor editorials. How convenient to have the answer to the question already prepared by the man who wrote it. All the busy delegates had to do was to rubber stamp the ready-made answer.

    WP7D was to have received a parallel contribution from the USA, by the same author, but unfortunately while the document was being considered at Arecibo, Hurricane Georges struck. Because of this accident, the document reached Geneva too late to be formally considered, but it was kindly made available to WP7D to help them deal with the liason statement from WP8D. Without the services of the WP7C drafting group WP7D was unable to complete the symmetric operation of sending back an acceptance of the compatibility study. Instead WP7D has sent back a liaison statement to WP8D indicating that there was not time to review the compatibility study and that comments might be expected after the next meeting of WP7D in March 1998.


    7. Abbreviations used in this Newsletter

    CEPT = Conference of European Post and Telecommunication administrations
    CRAF = Committee on Radio Astronomy Frequencies (ESF)
    EES = Earth Exploration Service(ITU-R)
    ERC = European Radiocommunication Committee (CEPT)
    ESF = European Science Foundation
    FM = ERC Working Group Frequency Management (CEPT)
    ITU = International Telecommunication Union
    ITU-R = ITU Radiocommunication Sector
    IUCAF = Scientific Committee on the Allocation of Frequencies for Radio Astronomy and Space Science
    MRC = Milestone Review Committee (ERC)
    MSS = Mobile-Satellite Service
    NRAO = National Radio Astronomy Observatory (US)
    PNDR = Preliminary Draft New Recommendation (ITU-R)
    RAS = Radio Astronomy Service (ITU-R)
    RDSS = Radio Determination-Satellite Service
    SE = ERC Working Group on Spectrum Engineering (CEPT)
    SR = Space Research (ITU-R)
    WARC = World Administrative Radio Conference (ITU)
    WP = Working Party (ITU-R)
    WRC = World Radiocommunication Conference (ITU-R)


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    Last modified: February 8, 1999