1. RFI2010 - RFI Mitigation Workshop 29 - 31 March, 2010, Groningen (NL) The RFI monitoring systems for the Medicina and the Sardinia Radio Telescope R. Ambrosini (IRA), P. Bolli (OAC), C. Bortolotti (IRA), F. Gaudiomonte (OAC), F. Messina (OAC), M. Roma (IRA) Osservatorio Astronomico di CagliariIstituto di Radioastronomia Sezione di Medicina

2. 2/26 P. Bolli, The RFI monitoring systems for the Medicina and the Sardinia Radio Telescope RFI2010 - RFI Mitigation Workshop 29 - 31 March, 2010, Groningen (NL) Agenda The Italian radio telescopes; Update of the SRT’s construction; The RFI monitoring systems of Medicina and SRT: Fixed station; Mobile station; Recent activity of the RFI group: (i) faraday room, (ii) wind farm, and (iii) routine measurements.

3. 3/26 P. Bolli, The RFI monitoring systems for the Medicina and the Sardinia Radio Telescope RFI2010 - RFI Mitigation Workshop 29 - 31 March, 2010, Groningen (NL) Matera operato da ASI Italian network

4. 4/26 P. Bolli, The RFI monitoring systems for the Medicina and the Sardinia Radio Telescope RFI2010 - RFI Mitigation Workshop 29 - 31 March, 2010, Groningen (NL) Fully steerable radio telescope for: Radio astronomy, Geodynamical studies, Deep Space Network, Single dish and VLBI 0.3-100 GHz continuous frequency coverage 64 m diameter primary mirror; 7.9 m diameter secondary mirror Gregorian configuration with Shaped Surfaces Active Surface: Primary mirror with 1116 actuators a) Compensate gravitational and thermal deformations b) Convert Shaped surface of the primary to a Parabolic surface for primary focus operation Six focal positions (up to 20 receivers): Primary, Gregorian, Four Beam Wave Guide Primary surface accuracy:  150 um RMS Pointing accuracy (RMS): 2 ÷ 5 arcsec SRT Technical Specifications

5. 5/26 P. Bolli, The RFI monitoring systems for the Medicina and the Sardinia Radio Telescope RFI2010 - RFI Mitigation Workshop 29 - 31 March, 2010, Groningen (NL) RA receivers for the first light Frequency bandNote 305 – 410 MHzPrimary, dual frequency 1.3 – 1.8 GHzPrimary, dual frequency 5.7 – 7.7 GHzBWG, mono-feed 18 – 26 GHzGregorian, multi-feed

6. 6/26 P. Bolli, The RFI monitoring systems for the Medicina and the Sardinia Radio Telescope RFI2010 - RFI Mitigation Workshop 29 - 31 March, 2010, Groningen (NL) RFI campaigns in Sardinia RFI Campaign Goals October 1992 RFI monitoring across South and Center Sardinia May 1996RFI monitoring in Gerrei area November 1997 RFI monitoring in Gennargentu area October 2002 RFI characterization of the site chosen to host SRT June 2004RFI measurement in the frequency bands of the first light receivers April 2007Joined campaign with RFI mobile laboratory and fixed station installed at the site

7. 7/26 P. Bolli, The RFI monitoring systems for the Medicina and the Sardinia Radio Telescope RFI2010 - RFI Mitigation Workshop 29 - 31 March, 2010, Groningen (NL) Features of SRT site The SRT site is located 35 Km North of Cagliari (700 m asl). Latitude: 39d 29m 50s N Longitude: 9d 14m 40s E 1.The site is well shielded by mountains sorrounding the radio telescope. 2.The area is far away from populated centers.

8. 8/26 P. Bolli, The RFI monitoring systems for the Medicina and the Sardinia Radio Telescope RFI2010 - RFI Mitigation Workshop 29 - 31 March, 2010, Groningen (NL) SRT update High level meeting between INAF and Communication Department of the Government are underway. Full support from National Administration.

9. 9/26 P. Bolli, The RFI monitoring systems for the Medicina and the Sardinia Radio Telescope RFI2010 - RFI Mitigation Workshop 29 - 31 March, 2010, Groningen (NL) 1.…. monitoring the frequency bands allocated by ITU to RAS. If man-made signals interfere with the radio astronomical observations, an official claim must be reported to the National Administration asking for protection. 2.…. monitoring also the out-of-RAS bands used by astronomers to observe the sky. The RFI information can improve the design of microwave receivers, the strategies of scientific observation, and the mitigation techniques. RFI monitoring system: goals

10. 10/26 P. Bolli, The RFI monitoring systems for the Medicina and the Sardinia Radio Telescope RFI2010 - RFI Mitigation Workshop 29 - 31 March, 2010, Groningen (NL) RFI monitoring system: scheme A fixed station with antennas placed on a tower close to the radio telescope A mobile laboratory to move closer to the RFI transmitter (i) receive the interference, (ii) collect as many data as possible of the RFI, (iii) identify the content of the signal, (iv) and detect the exact position of the transmitter (triangulation). (i) good sensitivity, (ii) high compression point, (iii) wide frequency bands, (iv) automatically (24 h / day) and remotely controlled.

11. 11/26 P. Bolli, The RFI monitoring systems for the Medicina and the Sardinia Radio Telescope RFI2010 - RFI Mitigation Workshop 29 - 31 March, 2010, Groningen (NL) Fixed RFI station: scheme

12. 12/26 P. Bolli, The RFI monitoring systems for the Medicina and the Sardinia Radio Telescope RFI2010 - RFI Mitigation Workshop 29 - 31 March, 2010, Groningen (NL) Microwave front-end

13. 13/26 P. Bolli, The RFI monitoring systems for the Medicina and the Sardinia Radio Telescope RFI2010 - RFI Mitigation Workshop 29 - 31 March, 2010, Groningen (NL) Fixed RFI station: comparison FeaturesMedicinaSRT (current version) Tower height25 m12 m Max frequency2.4 GHz3 GHz Antennas2 LPDA (80 – 500 MHz) 2 LPDA (500 – 1000 MHz ) 2 dual pol. Yagi (320 – 332 MHz) 2 dual pol. Yagi (400 – 416 MHz ) 2 dual pol. Yagi (606 – 612 MHz ) 1 reflector 1.2 m pol. 45° (1.3 – 2.4 GHz ) 1 LPDA (0.3 – 5 GHz) 1 LPDA (1.2 – 2.5 GHz) Rotor1 axis for azimuth direction2 axis for: azimuth direction and polarization Lenght & type of coaxial cable 35 m LCF ½” Cu2Y CELLFLEX (max 3 GHz) 55 m of FSJ4-50B Andrew (max 10 GHz) Spectrum Analyzer AGILENT 8562ECHP 8594 ReceiverICOM R9000ICOM R9500 >25 m 18 GHz Optical fiber link Satellite monitoring 1 Az-El reflector 1.5 m pol. 45° (1.1 – 12 GHz) Not yet available PSA 4446E

14. 14/26 P. Bolli, The RFI monitoring systems for the Medicina and the Sardinia Radio Telescope RFI2010 - RFI Mitigation Workshop 29 - 31 March, 2010, Groningen (NL) RFI towers MEDICINA SRT

15. 15/26 P. Bolli, The RFI monitoring systems for the Medicina and the Sardinia Radio Telescope RFI2010 - RFI Mitigation Workshop 29 - 31 March, 2010, Groningen (NL) RFI laboratories MEDICINA SRT

16. 16/26 P. Bolli, The RFI monitoring systems for the Medicina and the Sardinia Radio Telescope RFI2010 - RFI Mitigation Workshop 29 - 31 March, 2010, Groningen (NL) BandFrequency bandAntenna gain Chain gain Noise figure P 320 – 332 MHz14 dBi37 dB3 dB (300 K) 400 – 416 MHz15 dBi36 dB3 dB 606 – 612 MHz16 dBi32 dB3 dB L 1.29 – 1.73 GHz20 dBi34 dB3.5 dB S 2.20 – 2.34 GHz23 dBi33 dB3.5 dB Satellite monitor 1.1 – 12 GHz (AZ- EL) 19 dBi12 dB12 dB @ 10 GHz BandFrequency bandAntenna gain Chain gain Noise figure P 295 – 428.5 MHz6 dBi28 dB10.5 dB (3000K) L 1.18 – 1.80 GHz12.5 dBi22.3 dB10.0 dB S 2.07 – 3.39 GHz5.5 dBi15.7 dB13.0 dB Fixed RFI station: performance

17. 17/26 P. Bolli, The RFI monitoring systems for the Medicina and the Sardinia Radio Telescope RFI2010 - RFI Mitigation Workshop 29 - 31 March, 2010, Groningen (NL) Mobile RFI stations MEDICINA SRT

18. 18/26 P. Bolli, The RFI monitoring systems for the Medicina and the Sardinia Radio Telescope RFI2010 - RFI Mitigation Workshop 29 - 31 March, 2010, Groningen (NL) SRT Mobile RFI station

19. 19/26 P. Bolli, The RFI monitoring systems for the Medicina and the Sardinia Radio Telescope RFI2010 - RFI Mitigation Workshop 29 - 31 March, 2010, Groningen (NL) FeaturesMedicinaSRT VanFiat DucatoMercedes Sprinter 315 CDI Maximum seats32 Max frequency18 GHz (Normal operation) 40 GHz 18 GHz (Normal operation) 40 GHz Antennas1 LPDA (0.31 – 0.62 GHz) 1 LPDA (0.1 – 1.3 GHz) 1 LPDA (1.2 – 2.4 MHz) 1 dual ridge horn (1 – 18 GHz) 1 horn (18 – 26.5 GHz) 1 horn (26.5 – 40 GHz) 1 LPDA (0.3 – 0.6 GHz) 1 LPDA (0.1 – 1.3 GHz) 1 dual ridge horn (1 – 18 GHz) 1 dual ridge horn (18 – 40 GHz) Telescope pole height 11 m Telescope movement Up/down  servo Azimuth  manual Polarization  manual (standard 45°) Up/down  servo Azimuth  servo or manual Polarization  servo Equipped SASA HP 8562A (up to 26.5 GHz)PSA 4446 E (up to 44 GHz) Other characteristicsLaboratory + storehouse; anti-shock rack; self powered (auxiliary batteries / AC 220 V); GPS Mobile RFI station: comparison

20. 20/26 P. Bolli, The RFI monitoring systems for the Medicina and the Sardinia Radio Telescope RFI2010 - RFI Mitigation Workshop 29 - 31 March, 2010, Groningen (NL) BandFrequency bandAntenna gainChain gainNoise figure P 300 – 434 MHz5.5 dBi32 dB6 dB 604 – 611 MHz5.5 dBi29 dB9.5 dB L/S1.22 – 2.45 GHz4 or 9 dBi32 dB4.5 dB S2.45 – 4 GHz4.5 dBi26dB5 dB C4 – 8 GHz5 dBi28 dB4.5 dB X8 – 12 GHz6 dBi49 dB5 dB Ku12 – 18 GHz8 dBi37 dB8.5 dB K18 - 26.5 GHz21 dBi56 dB3.1 dB Ka26.5 – 40 GHz21 dBi50.5 dB4 dB BandFrequency bandAntenna gainChain gainNoise figure P 290 – 428 MHz9 dBi36.2 dB3.8 dB L 1.17 – 1.84 GHz7 dBi29.8 dB4 dB S 1.99 – 3.37 GHz7.8 dBi25 dB5.3 dB S / C 2.98 – 5.81 GHz12 dBi25 dB5.5 dB C / X 5.22 – 9.25 GHz11.5 dBiTBD X / Ku 7.76 – 18 GHz12.5 dBiTBD K / Ka 18 – 40 GHzTBD Mobile RFI station: performance

21. 21/26 P. Bolli, The RFI monitoring systems for the Medicina and the Sardinia Radio Telescope RFI2010 - RFI Mitigation Workshop 29 - 31 March, 2010, Groningen (NL) RFI measurements were conducted to evaluate the emission of a super-computing facility (80 nodes with dual CPU dual core each) to be placed at SRT. Goal of the measurement was to evaluate if the auto-interference are compatible with Rec. 769. If not, to identify the shielding level of a Faraday room to be installed at SRT station. Faraday room at SRT site

22. 22/26 P. Bolli, The RFI monitoring systems for the Medicina and the Sardinia Radio Telescope RFI2010 - RFI Mitigation Workshop 29 - 31 March, 2010, Groningen (NL) Faraday room at SRT site The figures we got (especially at frequencies lower than 1 GHz) exceed by about 60 dB, the detrimental values suggested by ITU-R RA.769-2 as the ones representative for continuum and spectral line radio astronomy observations.

23. 23/26 P. Bolli, The RFI monitoring systems for the Medicina and the Sardinia Radio Telescope RFI2010 - RFI Mitigation Workshop 29 - 31 March, 2010, Groningen (NL) RFI campaign at a wind farm Wind farmMonte Guzzini (CA) Number of turbins26 Electrical power (maximum) 22 Mwatt (850 Kwatt each) Modell of turbineVESTAS V-52 Dimension of each turbine Height of the mast 55 m, 3 blades with radius 26 m Type of measurement Primary emission (no reflection contribution)

24. 24/26 P. Bolli, The RFI monitoring systems for the Medicina and the Sardinia Radio Telescope RFI2010 - RFI Mitigation Workshop 29 - 31 March, 2010, Groningen (NL) RFI campaign at a wind farm Very strong wide band impulsive signal mainly in P (350 MHz) and L (1.5 GHz) bands associated electrical discharges in the power station of the wind farm. -85 dBW (0 dBi)

25. 25/26 P. Bolli, The RFI monitoring systems for the Medicina and the Sardinia Radio Telescope RFI2010 - RFI Mitigation Workshop 29 - 31 March, 2010, Groningen (NL) Routine RFI measurements Routine RFI measurements are conducted every week to monitor the band of interest for the first light of SRT. Power [dBm] with respect to 0 dBi (RBW=100 KHz) Frequency [MHz] External CW at 426 MHz The P frequency band of the dual frequency receiver was reduced from 305-425 MHz to 305-410 MHz. Two identical HTS microwave band-pass filters are underway in collaboration with Prof. Lancaster and Dr. Huang (Univ. of Birmingham)

26. 26/26 P. Bolli, The RFI monitoring systems for the Medicina and the Sardinia Radio Telescope RFI2010 - RFI Mitigation Workshop 29 - 31 March, 2010, Groningen (NL) Conclusions SRT is very close to its inauguration; A team of local technicians has been trained to take care of the RFI problems; SRT is in progress to be equipped with state-of-the-art RF instrumentation for monitoring the RFI, following the thirty-year experience gathered at Medicina; The RFI activity consists both: (i) in routine measurements at the site, and (ii) in ad hoc campaign addressed to specific questions.