1. 上海天文台 Shanghai Astronomical Observatory RFI Environment at the Shanghai Sheshan Site Zhi-Qiang Shen, Bin Li, and Tao An (Shanghai Astronomical Observatory) “RFI2010 - RFI Mitigation Workshop” 29 - 31 March, 2010, Groningen (NL)

2. 上海天文台 Shanghai Astronomical Observatory Major Facilities for RA in China Delingha 13.7m 21CMA

3. 上海天文台 Shanghai Astronomical Observatory Telescope site （ 30-40 km away ） Headquarter of ShAO Location of the Shanghai Sheshan Site

4. 上海天文台 Shanghai Astronomical Observatory Diameter: 25m Band: L, S/X, C, K VLBI Recording system: MK4, MK5A, MK5B Shanghai Sheshan 25m RT (1987)

5. 上海天文台 Shanghai Astronomical Observatory Location 5 多波束射电接收时代的天体物理 南京 2009 年 9 月 6.1 KM 4 KM 2.4 KM 25m RT 65m RT

6. 上海天文台 Shanghai Astronomical Observatory Shanghai 65m Radio Telescope  65-m in diameter fully steerable radio telescope  Active surface  Cover 1.4 – 46 GHz with 8 bands ： L(1.6GHz) S/X(2.3/8.4GHz) C(5GHz) Ku(15GHz) K(22GHz) Ka(30GHz) Q(43GHz)  General-purpose (radio astronomy, geodynamics, single- dish, VLBI ) 6

7. 上海天文台 Shanghai Astronomical Observatory  Frequency coverage: 1.4~46 GHz  Aperture Efficiency ： L/S/C >60%, X >55%, Ku >40%, K >20% Ka >50%, Q >45% (with active surface)  Surface accuracy ： 0.6mm RMS (without active surface) 0.3mm RMS (with active surface)  Pointing accuracy ： 3 arcsec (wind < 4m/s) 10 arcsec (wind < 10m/s) 30 arcsec (wind < 20m/s)  First secondary lobes: <20 dB under main  Elevation limits: 5~90 degree  Slew rates: 0.5 degree/s (azimuth), 0.3 degree/s (elevation) Telescope Specifications 7

8. 上海天文台 Shanghai Astronomical Observatory Receiver Specifications Band Frequency Range (GHz) Bandwidth (GHz) BW/CF (%) Polarization T REC (K) T LNA (K) L (18 &21cm) 1.25 ～ 1.80 0.5032Lin/Circ10< 5 S (13cm) 2.15 ～ 2.45 0.3013Circ12< 5 C (5 &6cm) 4.50 ～ 7.00 2.5043Lin/Circ16< 5 X (3.6cm) 8.00 ～ 9.00 1.0012Circ15< 5 Ku(2.2cm) 12.00 ～ 15.50 3.5025Circ15< 6 K (1.3cm) 18.00 ～ 26.50 8.5038Circ21< 10 K a(9mm) 30.00 ～ 34.00 4.0013Circ25< 12 Q(7mm) 40.00 ～ 46.00 6.0014Circ40< 18 Note: S/X and X/Ka are dual-frequency bands 8

9. 上海天文台 Shanghai Astronomical Observatory  2008 ： funded, contract to CETC54 for the antenna construction  2009: complete design, start manufacturing  2010: foundation completed  2011: antenna completed  2012: L/S/C/X band test observations, ready for participation in the Chinese Lunar Mission  2013-14: active surface tested, Ku/K/Ka/Q band test observations  2015: project finished Project Timeline 9

10. 上海天文台 Shanghai Astronomical Observatory 10 多波束射电接收时代的天体物理 南京 2009 年 9 月

11. 上海天文台 Shanghai Astronomical Observatory L 波段的详细测试图 LNA =40dB. 1200MHz~1520MHz ，测试天线水平极化，以下四附图依次为天线指向东南西北四个方向测到的频谱图  L: 1.25 ～ 1.80GHz 1.25—1.52 GHz East South West North

12. 上海天文台 Shanghai Astronomical Observatory  L: 1.25 ～ 1.80GHz 1.52—1.80 GHz

13. 上海天文台 Shanghai Astronomical Observatory  S: 2.15 ～ 2.45GHz C:4.5 ～ 7.0 GHz

14. 上海天文台 Shanghai Astronomical Observatory  C:4.5 ～ 7.0 GHz X:8.0 ～ 9.0 GHz

15. 上海天文台 Shanghai Astronomical Observatory  9.2 ~ 17.8 GHz

16. 上海天文台 Shanghai Astronomical Observatory Active surface control  Compensate (repeatable) gravitational deformations, to maintain the nominal shape of the primary reflector (to improve the efficiency at high frequencies)  Used on the USA GBT 100-m and Italy Noto 32-m 16

17. 上海天文台 Shanghai Astronomical Observatory EMC testing with 300kg load 17

18. 上海天文台 Shanghai Astronomical Observatory Results from EMC testing 18 Power-on & in motionPower-on & hold still

19. 上海天文台 Shanghai Astronomical Observatory solutions  Administrative level: Shanghai Radio Administration Bureau Was done in 1990’s Good contact  Hardware: Superconductor filter Shielding etc  Software: learned from this workshop 19

20. 上海天文台 Shanghai Astronomical Observatory Superconductor Filter  Mitigate strong RFI which saturates the first cryogenic LNA.  Working at 10~20K, low loss, low phase degeneration. Example  Frequency: 2.2~2.3GHz (3G mobile RFI@ 2.14GHz)  Style: hairpin, 12 sections  Material: thin film TL-2212  Insertion loss: 0.05dB at 20K 20

21. 上海天文台 Shanghai Astronomical Observatory Superconductor Filter Provided by CETC-16 institute 21

22. 上海天文台 Shanghai Astronomical Observatory Conclusions and Future Work  RFI has become an important issue to the sites of radio telescopes in China  Observatory will pay close attention to both the technical and regulatory issues related to RFI  Superconductor filter (considered for 65m)  Shielding (under consideration)  Softwares  …  Spectrum management at different levels  Origins of RFI (Shanghai Radio Administration Bureau)  More frequent RFI monitoring is necessary to ensure a reliable assessment at Shanghai Sheshan site 22