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RFI & Spectrum Management

RFI & Spectrum Management. Murray Lewis. Cooperative Agreement with NSF Charge #5 Maintain a vigilant awareness of the radio frequency environment of the Observatory through a program of RFI monitoring, and take all appropriate steps to

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RFI & Spectrum Management

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  1. RFI & Spectrum Management Murray Lewis AUSAC Meeting 9-10 March 2009

  2. Cooperative Agreement with NSF Charge #5 Maintain a vigilant awareness of the radio frequency environment of the Observatory through a program of RFI monitoring, and take all appropriate steps to mitigate to the extent possible the impact of such signals on the Observational mission of NAIC. AUSAC Meeting 9-10 March 2009

  3. Radio Frequency Interference (RFI) • unwanted man-made radio signals in data == RFI • the radio spectrum is coveted by many users • Commercial sector • Government • Military • Scientific users • radio spectrum must be shared and managed • active users may contaminate adjacent spectrum with spurious and unnecessary emission thus causing RFI AUSAC Meeting 9-10 March 2009

  4. Sources of RFI • RFI Source Regulatory Body • Site Inadvertent Arecibo Staff • PR Radar, Military FCC, PRSUG • Global Satellite, Aircraft FCC, NTIA, CORF, ITU • NAIC acts on RFI matters through an internal committee: • Spectrum Management and RFI Group (SMARG) • Meets monthly, Minutes on the internal web • Attended by Site Director, Head Astronomy Dept., & Yervant Terzian • Spectrum Management at Arecibo -- ~1.5 FTE • Rey Velez (0.4 FTE), Murray Lewis (~.4 FTE), Phil + others (~.7 FTE) AUSAC Meeting 9-10 March 2009

  5. SPECTRUM MANAGEMENT AUSAC Meeting 9-10 March 2009

  6. HILLTOP MONITOR 1 - 10 GHz data available from AO Web AUSAC Meeting 9-10 March 2009

  7. Output Hilltop Monitor daily average 30/10/2002 AUSAC Meeting 9-10 March 2009

  8. Hilltop Monitor 1200-1450 MHz AUSAC Meeting 9-10 March 2009

  9. Fractional Occupation of 0.1 MHz bins AUSAC Meeting 9-10 March 2009

  10. Site-Generated RFI • We are often our own worst enemy == eternal need for vigilance • Vet all new equipment before it is installed • tertiary reflector controls • telescope tie-down electronics • cell-phone detectors • Monitor installed equipment for RFI • deterioration of shielding due to oxidation of seals • wear & tear on equipment seals • installation of improvements to RFI shielding, etc AUSAC Meeting 9-10 March 2009

  11. RECENT Hill top monitor overhauled and reinstalled 430 MHz transmitter and amateurs: event day for amateurs Space shuttle coordination Coordination with GPS, Iridium, GlobalStar, Puntas Salinas Coming License application for 3rd HF frequency Coordination negotiation about 5 GHz birdies (Neptuno!!) AUSAC Meeting 9-10 March 2009

  12. Puerto Rican Issues • Federal regulations apply to Puerto Rico • PRCZ was set up on September 26th, 1997 • allows the Observatory to comment on license requests made to the FCC (Federal Communication Commission) • PR Spectrum Users Group (PRSUG) • provides a forum for making contacts with island spectrum managers • provides notice of new developments • eases coordination - eg with Punta Salinas • Current island issues • TARS MoU to be revised • X-band (CASA) weather radars expected (9.41 GHz) AUSAC Meeting 9-10 March 2009

  13. Global Concerns • FCC, NTIA == US Domestic Regulators • CORF == National Academy of Science’s Committee on Radio Frequencies • International Telegraphic Union ( ITU ) • ITU regulations provide for the protected RAS bands • allocate particular pieces of spectrum to particular classes of users • provide guidelines for interpreting spurious & out of band emissions • provide guidelines for interpreting “harmful levels” of emission • band-sharing coordination, etc • provisions for radio astronomy from space == need for foresight • IUCAF: unfettered voice of radio astronomers at the ITU • obtained an MoU with Russians re GLONASS • rallying point in dealing with Iridium satellite incursion AUSAC Meeting 9-10 March 2009

  14. CURRENT GPS 1381 MHz use -- coordination (US domestic issue) GPS administration offered to code a software mitigation solution for much of their L3 signal Lou Nigra (Wisconsin pre-doc) engaged to provide the Arecibo end of this project (test data, receiver calibration/linearity, and implementation) with help of Electronics Dept. engineers. Method based on Ellingson et al, APJS 135, 87 (2001) Analog-digital transition: #54 will go off the air, site visit AUSAC Meeting 9-10 March 2009

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