Draft CORF Minutes

13-14 May 1998

Action items are in italics, appendices are copies of the viewgraphs used by each speaker.

Attendance

CORF members: Michael Davis, Chair; David Brooks, Russell Chadwick, Darrel Emerson, Michael Klein, Thomas Kuiper, Mark McKinnon, Ram Narayanan, Paul Steffes (by phone), Wolf Vogel

Guests: Jacob Baars, U. of Massachusetts; Richard Barth, DOC; Joseph Camacho, NTIA; Patrick Crane, NRL; Toni Feder, Physics Today; Tomas Gergely, NSF; Celso Gutierrez, INAOE, Mexico; Charles Iseman, FCC; John Kiebler, Consultant; Eduardo Mendoza, IANOE, Mexico; John Miller, Stanford Telecom; Alfonso Serrano, INAOE, Mexico; Titus Spoelstra, CRAF; Ken Tapping, DRAO, Canada (by phone); A. Richard Thompson, NRAO; Charles Wende, NASA; John Zuzek, NASA

Introductions

Michael DAVIS welcomed members and guests of the committee, and particularly thanked Eduardo MENDOZA, Alfonso SERRANO, and Celso GUTIERREZ from INAOE in Mexico for their participation. DAVIS recused himself from issues regarding Iridium and the Puerto Rico Coordination Zone.

NRC Matters

NRC Senior Program Officer Robert RIEMER described the new NRC rules made in response to Public Law 105-153, the Federal Advisory Committee Amendments Act, and explained how they affect CORF (Appendix A).

NSF Report

Tomas GERGELY reported (Appendix B) on

GERGELY presented a timeline of the activities leading to the signing of a Coordination Agreement between IRIDIUM and Arecibo Observatory.

WARC-92 allocated 1452 - 1492 MHz to Digital Sound Broadcasting. WorldSpace Corp. plans to launch three geosynchronous satellites during the coming year, ASIASTAR, AFRICASTAR and CARIBSTAR., to provide audio service to these areas using low cost receivers. DAVIS, GERGELY and THOMPSON visited WorldSpace headquarters in Washington in April, to hear their plans to protect the Radio Astronomy allocation 1400 - 1427 MHz, following receipt of a paper by Govind Swarup (Indian GMRT) indicating that unfiltered spread spectrum transmissions could exceed detrimental limits by up to 50 dB. They learned that Alcatel is fabricating the satellites in France. Each satellite has three dual-polarized beams, and is provided with filters following each of the six final amplifiers to suppress unwanted emission. Measurements presented by WorldSpace indicate that the signal level is expected to be below the detrimental level. A more detailed paper on this subject has just been received from Alcatel, and will be distributed to CORF members.

NTIA Spectrum Reallocation

Congress mandated transfer of 20 MHz from government to private use in 1997. After extensive discussion NTIA's recommended transfers include 1385-1390, 1432-1435 and 2385-2390 MHz. These are all close to radio or radar astronomy bands, and there future use will require close coordination. GERGELY noted that excludingprotection of the RAS band 608-614 MHz from the reallocation required a letter to NTIA from NSF director LANE.

World Radio Conference Results And Preparations

WRC-97 did not include radio astronomy on the agenda, but nevertheless included a number of actions that could affect radio astronomy allocations. WRC-97 deleted the Fixed Satellite Service from 15.4-15.43 GHz to protect the neighboring RAS band. It allocated 40.5-42.5 GHz to the FSS, right next to the 42.5-43.5 GHz RAS band, but no FSS use of 41.5-42.5 GHz will be permitted until completion of sharing studies. A cloud radar band was added at 94.1 GHz. The very relaxeds spurious emission limits proposed by Task Group 1/3 were approved. It is recognized that these are inadequate for protection of the Radio Astronomy Service, which will continue to need coordination on a case by case basis.

World Radio Conference Preparations

The next World Radio Conference is presently scheduled for the fall of 1999 in Geneva. Information about US preparations for WRC-99 can be found on the NTIA and FCC web sites.

WRC-99 has the following RAS-related items on its draft agenda (the people in parentheses may be able to act as points of contact for the topics):

The reconsideration of allocations above 71 GHz involves a major review of both radio astronomy and remote sensing spectrum, with the goal of updating the allocations to conform with current requirements. GERGELY noted that this is a major revision, and requires significant preparation well in advance of the meeting. In general, the 3, 2 and 1 mm atmospheric windows need to be consolidated, with satellite transmissions at the edge of the windows. In general, astronomy can share with terrestrial services if an adequate buffer zone is placed around the RAS mm wavelength sites.

The Large Millimeter Telescope (LMT) is presently being designed for installation on a mountaintop in Mexico. It is a joint project between the University of Massachusetts and the Instituto Nacional de Astrofisica, Optica y Electronica (INAOE) in Mexico. Four representatives of this project attended the CORF meeting, and exchanged ideas about protection of the spectrum for this new instrument, particularly in light of the WRC-99 review of short wavelength allocations. This became part of the larger question of regional spectrum management issues discussed below.

Public Education

GERGELY described plans for an NSF film describing scientific use of the radio spectrum. The contract for the film has been let, and production is about to begin. The intent is to have the film ready for viewing by WRC-99 participants. It will also be available for many other purposes, including exhibition at Observatory visitor centers and public lectures.

ITU-R Working Party 7D Meeting at NSF

GERGELY announced that the next meeting of ITU-R Working Party 7D (Radio Astronomy) will take place at the NSF, probably during the second week of June. He and THOMPSON pointed out that it is essential that more radio astronomers participate in these meetings. DAVIS and THOMPSON will draft a letter to Observatory directors, asking that each radio Observatory be represented at these important planning meetings.

NASA OFFICE OF EARTH SCIENCE REPORT

Charles WENDE provided a report from the NASA Office of Earth Science (Appendix C)

His presentation included

WRC-97 dealt with many remote sensing issues. Appendix C provides a summary table of the results, which were largely favorable for remote sensing interests. An exception is failure in an attempt to upgrade the status of the 18.6-18.8 GHz band from secondary to primary worldwide. The allocations in the 50-60 GHz band were reallocated to harmonize the use by passive services with other services.

WRC-97 dealt with remote sensing issues below 71 GHz. Allocations above 71 GHz will be considered in WRC-99.

Efficient Spectrum Usage

The Space Frequency Coordination Group initiated studies on efficient modulation techniques, following complaints from the radio astronomy community and others that simple spread spectrum techniques can place unwanted emission too far outside the useful bandwidth. Studies have been completed by both JPL and the European Space Agency, with details given in Appendices D and E. The studies provide comparison of binary phase shift keying, quadrature phase shift keying, offset quadrature, Gaussian minimummean shift keying and Fejer quadrature. The latter two provide more than 60 dB attenuation less than 2.5 times the required bandwidth, a factor of 16 better than BPSK bi-phase.

Based on these studies, SFCG New Draft Recommendation 17-4-1 (Provisional, 90/25/97) (Appendix F) recommends a spectral mask for missions launched after the year 2000 that drops 60 dB at bandwidth to data rate ratios of 3 (single-sided) for high data rates, and 8 for medium data rates. Details of the recommendation and mask are shown in the appendix. CORF members noted that use of this mask will address some of the serious concerns raised by naïve use of spread spectrum modulation techniques in satellite downlinks.

WENDE noted that the EOS AM-1 spacecraft downlinks of science data in the 8250-8400 MHz range will cause some interference to the Deep Space Network receivers in the 8400-8450 MHz band. Various Active coordination will be required, and various options have been considered. The interference will occur at most for a few minutes per orbit. Details are in the appendix. This band is also in use at the VLA and VLBA, using the receivers designed for support of the extended outer planet missions at the request of NASA.

WENDE provided an example of remote sensing use of the band 1400-1427 MHz, to measure sea surface salinity in Chesapeake Bay and soil moisture over land. The MIRAS satellite will have 1K sensitivity and better than 50 km resolution in this band.

John ZUZEK, NASA Lewis Research Center, and Chair of Working Party 7C, discussed passive sensor issues on the WRC-99 agenda (Appendix G). These included:

Meteorological Radio Research

Richard BARTH, National Oceanic and Atmospheric Administration, Department of Commerce, described the meteorological needs:

European Committee on Radio Astronomy Frequencies

Titus SPOELSTRA, European Committee on Radio Astronomy Frequencies, explained the spectrum management structure in Europe (Appendix H). CRAF is composed of representatives from 16 countries., Tthe CEPT (which is similar in some respects to the FCC) is composed of 42 members states, and the European Science Foundation has 62 members. An example of the type of issues that can occur is when satellite uplinks affect a national areanationally whereas downlinks affect the whole European regionregionally. He mentioned the European Milestone Review Committee for Iridium (Appendix I). The European Common Allocation Table for 29.7 GHz to 105 GHz, so far, is at www.ero.dk.

CANADIAN-MEXICAN-U.S. REGIONAL ISSUES

Ken TAPPING, Dominion Radio Astrophysical Observatory, Canada, participated in a discussion by telephone. He reported on the negotiations with Iridium and "Industry Canada", which is analogous to the FCC in the U.S. They have a 5 year license condition with renewal dependent on satisfying ITU-R RA769R. 769, the -238 d BW/m2/Hz limit for interference for radio astronomy.

Jaap BAARS, University of Massachusetts, spoke on the Large Millimeter Telescope, a joint project with Mexico’s Instituto Nacional Astrofisica, Optica, y Electronica (INAOE). He was joined by INAOE staff members Alfonso SERRANO Pérez-Grovas, LMT Project Director; Eduardo MENDOZA, and Celso GUTTIEREZ. The LMT project is in the detailed design phase. Dedication is set for 2000, commissioning in 2001. This will be the first large radio astronomy facility in Mexico and will present both project and national radio management issues. Frequency management in Mexico follows the ITU generally, below 24 GHz, and is mostly telecommunications. Mexico participated in WG5 and WG7 at the 1997 WRC. The Secretary of Communications and Transport must give approval. High-density services, expect to see 38-40 GHz being used in the near future.

GERGELY emphasized that it is important for CORF to broaden its scope and involve Mexico and Canada in issues of regional importance to scientists, especially as large projects are becoming more international. TAPPING agreed that regional coordination is important. RIEMER said the Academies of the U.S. and Mexico have a joint agreement on committee membership, so that it might be possible to add members to CORF or enlarge it to include a joint US-Mexican subgroup. He will explore setting up a similar relationship with Canada.

INTERNATIONAL TELECOMMUNICATION Union—radiocommunication Sector

Richard THOMPSON spoke on ITU-R matters (An organizational chart was presented by Charles WENDE in Appendix J). Several issues are being worked on:

National TELECOMMUNICATIONS and INFORMATION ADMINISTRATION

Joe CAMACHO, NTIA, presented findings of the new Radio Astronomy Spectrum Planning Options report (Appendix L). He noted that Radio Astronomy hasn’t added to its available bandwidth since the era of "the molecular explosion". The committee was especially interested in the 94, 140, and 230 GHz issues, and the specification of millimeter-wave imaging interference criteria.

Federal COMMUNICATIONS Commission

Charles ISEMAN, Chief of the Spectrum Policy Branch, FCC, reported on the status of various FCC decisions:

He also warned about Congressional pressure to auction spectrum. and handling federal/nonfederal spectrum.

Views from the American Astronomical Society

Patrick CRANE, chair of the AAS Commission on Light Pollution, Radio Interference, and Space Debris, presented issues for CORF’s consideration:

SECOND DAY

The second day of the meeting was declared by the Chair to be in open session.

LATE-BREAKING SATELLITE NEWS

GERGELY presented just-released information on the source of interference at 328 MHz. This signal has been detected since 1992, mainly by lower frequency European and Indian radiotelescopes (Appendix M). It is caused by a U.S. defense satellite, UTEX, whose gravitational gradient stabilization has malfunctioned. The satellite is in a high-altitude polar orbit with no way to permanently disable the transmitter. He emphasized the need for contractors to check with the ITU Radio Astronomy handbook to ensure their satellites are not broadcasting in protected bands. GPS-L3 at 1381.05 MHz scheduling also took a long time to fix.

IUCAF

SPOELSTRA noted that IUCAF, the Inter-Union Commission for the Allocation of Frequencies [which is under the International Astronomical Union (IAU), the International Union of Radio Science (URSI), and the Committee on Space Research (COSPAR)] has been raised to the status of an ICSU commission, e.g., such as COSPAR, the Committee on Space Research. IUCAF is chaired by Willem BAAN, who is the new director atof Dwingeloo (or /Westerbork?). CRAF provided input on millimeter-wave telescopes to WP7D and PT33 for WRC-99, and to TG 1-5 on out-of-band emissions and unwanted emission. As an IUCAF member you may attend a WRC even when the quota for your country is full. IUCAF has direct representation at also provides a direct route to the ITU. Brian Robinson is writing a history of the first 25 years of IUCAF for the Annual Review of Astronomy and AstrophysicsAstronomy (?) Journal. SPOELSTRA mentioned that Commsphere Afrique had been held and that Commsphere 99 would be held in January in Toulouse, France. He mentioned that there will be sessions at the Committee on the Peaceful Uses of Outer Space, which will meet at Unispace3 in July 1999 in Vienna. The International Union of Radio Science’s Commission E on Electromagnetic Noise and Interference will meet in Toronto in August 1999.

IRIDIUM

Dick THOMPSON distributed a report on measurements offor the Iridium system downlink transmissions (Appendix N). The same band is used for up- and down-links, with a time set for each.

LEGAL ISSUES FOR CORF

Paul FELDMAN, CORF’s telecommunications attorney from Fletcher, Heald & Hildreth, reported on issues for CORF to watch. These included:

FELDMAN addressed several questions and comments:

WRC-99 Preparations

CORF should support international millimeter-wave working group. EMERSON and KUIPER are members. CORF’s revised Views are needed before the end of 1998. NARAYANAN and KUIPER will work on a list of frequencies. CORF needs IUCAF output by June 1998 or it will have to use the existing list. CORF should provide input to national WP7D. SPOELSTRA mentioned that CRAF has provided input to WP7D and terms of reference to PT33 for frequencies greater than 71 GHz. The draft is based on existing allocations, result is that bands will have allocations for radio astronomy and remote sensing. A second draft is due the second week of June 1998. Final draft dealing with frequencies up to 275 GHz is due in September. GERGELY mentioned that the U.S. may ask for a delay to May 2000, but that the CPM was set for May 19998. The U.S. millimeter-wave working group will pass data to MENDOZA.

NARAYANAN discussed the remote sensing needs for soil moisture studies at 1400-1427 MHz. Millimeter-wave sensors yield measurements of the surface layers and allow evaporation studies. They also permit geophysical parameter estimation.

Other Action Items

Other topics and action items include the following: