1. Radio Quiet Zones (RQZ) Tasso Tzioumis ATNF, CSIRO RAFCAP

2. Why? -- Need for RQZ? RA systems extremely sensitive  very susceptible to RFI RA allocated very little spectrum (~2% at cm ) –Still RFI from out-of-band (OoB) emissions RA operates over full radio spectrum  RFI from radiocommunication services “prevention better than cure”  RQZ is 1 st step of mitigation

3. What? -- Radio Quiet? Radio Quiet  Radio Silent “Passive” bands (e.g. 1400-1427 MHz) –“all emissions are prohibited” (Fn. 5.340) –but OoB emissions still a problem RQZ  prevent “harmful” (detrimental) RFI RFI mitigation – minimise “harm”  may influence RQZ limits & area

4. RQZ selection - Population? Sydney: population 4 million Narrabri: population 4000 Mileura: population 4

5. Where are the Quiet areas?

6. RQZ History National RQZ –Within an administration –Sovereign rule – can depart from ITU –Regulate terrestrial services –Little or no impact on satellite services International RQZ –Moon & L2 point

7. National RQZ characteristics 2 distinct areas of RQZ protection 1.EMC protection –RFI from electrical/electronic equipment –Protect to few kms (5-20) – 30 for heavy industry –Local/State Governments 2.Coordination zone –Coordinate with radio transmitters –100s of km –Communications administration

8. Greenbank NRQZ The original RQZ - model 1956 – West Virginia Radio Astronomy Zoning Act –Graded EMC restrictions to 10 miles 1958 – NTIA & FCC  National RQZ –34000 sq km area –Coordination of all Tx with RA telescope Excellent protection in practice

9. Other National RQZs Arecibo PRCZ – Puerto Rico & islands –Coordination Zone Jodrell Bank & other European telescopes –Mainly EMC (local) & some National coordination GMRT –EMC – 10 km (light)  30 km (heavy industry) –National coordination up to 400 km (bands)

10. ALMA Quiet Zone -- Chile Central Quiet zone: 30 km radius, no transmitters in ALMA bands (variously 31 to 950 GHz) 120 km radius coordination zone – AUI/ESO may comment on xmit applications > 31 GHz, comply with 769 at site boundary < 31 GHz, 769 + limit on transmitter power – Eirp such that pfd at ALMA border <2x10 -6 W/m 2 Formal recognition is needed to avoid future changes in policy. Need to educate the general public and politicians about radio astronomy and the need for radio quiet zone.

11. “Radio sensitive zones” in Australia Radio Act review 2002 – “radio sensitive zones” –Notification and coordination - no protection Regulatory RALI (2006) to cover all Oz RA sites Studies by ACMA (administration)

12. Notification Zone Parameters Limits derived from RA.769 (+ ~10-15 dB) Propagation models from P.526 (Diffraction) and terrain models.

13. Notification zone limits Limits derived from RA.769 –+10 dB at Parkes for 30 deg Elevation limit –+15 dB at ATCA for array –VLBI levels at other stations

14. International RQZs Shielded Zone of the Moon RQZ –ITU-R Rec RA.479 - Entire radio spectrum –No levels defined – coordination –But some RFI from spacecraft (e.g. Mars) –Prohibitively expensive Sun-Earth Lagrangian Point L2 –ITU-R Rec RA.1417 –1.5 million km from Earth –Excellent RQZ – WMAP (CMB) already there!

15. OECD Global Science Forum OECD “Task Force on Radio Astronomy and the Radio Spectrum” (Report 2004) –RA and Satellite Operators Recommendations: 1.Technical consultations 2. “Controlled Emission Zones” 3.ITU-R efforts 4.Operational consultation Leverage for international RQZ?

16. ITU-R Question Question in WP7D to initiate studies Strong opposition from satellite operators Question delicately framed i.e. 1.Characteristics of existing RQZ? 2.RAS characteristics stimulating RQZ? 3.environment characteristics stimulating RQZ? Work still to be done.

17. Square Kilometre Array  ~ 1 km 2 collecting area in an interferometer array sensitivity ~50 x EVLA (current largest radio array) survey speed >10000 x faster than EVLA wide frequency range: 0.1 – 25 GHz configuration: longest baselines >3000 km; 50% collecting area<5km wide field of view: 50 sq. degree at <1 GHz (250 x moon) total cost 1 B€; operating costs 70 M€/year

18. RQZ for SKA? SKA to operate 100 MHz – 25 GHz –Wide unprotected frequency range –Must have some RQZ protection National efforts towards SKA RQZ(s) –All site proponents must define progress towards RQZ protection. Protection now for SKA demonstrators / pathfinders –Preserve “quiteness” of sites –e.g. Australia started with a “spectrum embargo” for 100-150 km radius around Mileura site.

19. RQZ guidelines - SKA Regulatory “Task Force” Report covers Protection criteria and general discussion on methodology. Threshold levels: –“Central site” - RA.769 levels (cont & line) –Up to 150km - RA.769 Table 1 +15dB (array levels) –Remote sites - RA.769 VLBI levels Radio propagation modelling (ITU Recs) Complex and many assumptions

20. South Africa Astronomy Reserve

21. South Africa Legislation: Astronomy Geographical Advantage Act Empowers the Minister for Science and Technology to declare protected areas around strategic astronomy sites by publication in the Government Gazette. The Act empowers the Minister to prohibit over-flights The Act covers both radio and optical astronomy Three tiers of protected areas: –Core area – the physical area of the observatory / instrument –Central area – surrounds the core area. Minister prohibits certain activities / categories of activities in this area –Coordination area –Minister sets standards which activities must comply with Protected areas apply to existing and new activities

22. Australia + NZ

23. SKA RQZ in Australia Studies & definition by ACMA & CSIRO RALI MS32 - in force since 24/9/2007

24. Oz RQZ procedures From RALI MS32

25. Summary & lessons learned RQZs important for RA – 1 st step in mitigation –National “RQZ”s - coordination only –Weak enforcement RQZ essential for SKA –Exclusion and coordination zones –Strong Enforcement Lesson from Oz experience: ** Work closely with national administration ** ITU Question on RQZ – towards IRQZs? –Inputs from SKA RQZ experience

27. Inner core Station Reference Design Wide-angle radio camera + radio “fish-eye lens”

28. RA. 769 thresholds