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

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Presentation on theme: "AUSAC Meeting 9-10 March 2009 RFI & Spectrum Management Murray Lewis."— Presentation transcript:

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

2 AUSAC Meeting 9-10 March 2009 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.

3 AUSAC Meeting 9-10 March 2009 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 Radio Frequency Interference (RFI)

4 AUSAC Meeting 9-10 March 2009 Sources of RFI RFI Source Regulatory Body SiteInadvertentArecibo Staff PRRadar, MilitaryFCC, PRSUG GlobalSatellite, AircraftFCC, 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)

5 AUSAC Meeting 9-10 March 2009 SPECTRUM MANAGEMENT

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

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

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

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

10 AUSAC Meeting 9-10 March 2009 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

11 AUSAC Meeting 9-10 March 2009 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!!)

12 AUSAC Meeting 9-10 March 2009 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)

13 AUSAC Meeting 9-10 March 2009 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

14 AUSAC Meeting 9-10 March 2009 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


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