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Radio Quiet Zones (RQZ) - working with your national administration. Tasso Tzioumis Australia Telescope National Facility (ATNF) Tasso.Tzioumis@ .csiro.au COSPAR2008 – Montreal 14 July 2008. Why? -- Need for RQZ?. RA systems extremely sensitive  very susceptible to RFI

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radio quiet zones rqz working with your national administration

Radio Quiet Zones (RQZ)- working with your national administration

Tasso Tzioumis

Australia Telescope National Facility (ATNF)

Tasso.Tzioumis@ .csiro.au

COSPAR2008 – Montreal 14 July 2008

why need for rqz
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 1st step of mitigation

what radio quiet
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

rqz selection population
RQZ selection - Population?

Sydney: population 4 million

Narrabri: population 4000

Mileura: population 4

rqz history
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
national rqz characteristics
National RQZ characteristics
  • 2 distinct areas of RQZ protection
  • EMC protection
    • RFI from electrical/electronic equipment
    • Protect to few kms (5-20) – 30 for heavy industry
    • Local/State Governments
  • Coordination zone
    • Coordinate with radio transmitters
    • 100s of km
    • Communications administration
greenbank nrqz
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
other national rqzs
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)
alma quiet zone chile
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/m2
  • 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.
radio sensitive zones in australia
“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)
notification zone parameters
Notification Zone Parameters
  • Limits derived from RA.769 (+ ~10-15 dB)
  • Propagation models from P.526 (Diffraction) and terrain models.
international rqzs
International RQZs
  • Shielded Zone of the Moon RQZ
    • ITU-R Rec RA.479 - Entire radio spectrum
    • No levels defined – coordination
    • But some RFIfrom 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!
oecd global science forum
OECD Global Science Forum
  • OECD “Task Force on Radio Astronomy and the Radio Spectrum” (Report 2004)
    • RA and Satellite Operators
  • Recommendations:
    • Technical consultations
    • “Controlled Emission Zones”
    • ITU-R efforts
    • Operational consultation
  • Leverage for international RQZ?
itu r question
ITU-R Question
  • Question in WP7D to initiate studies
  • Strong opposition from satellite operators
  • Question delicately framed i.e.
    • Characteristics of existing RQZ?
    • RAS characteristics stimulating RQZ?
    • environment characteristics stimulating RQZ?
  • Work still to be done.
square kilometre array ska
Square Kilometre Array (SKA)
  • ~ 1 km2 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
slide18

SKA Reference Design

Inner core

Station

Wide-angle radio camera + radio “fish-eye lens”

rqz for ska
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.
    • Short list: Australia & South Africa
  • 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.
rqz guidelines ska regulatory task force
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
south africa legislation astronomy geographical advantage act
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
ska rqz in australia
SKA RQZ in Australia
  • Studies & definition by ACMA & CSIRO
  • RALI MS32 - in force since 24/9/2007
oz rqz procedures
Oz RQZ procedures
  • From RALI MS32
oz rqz emc 1
Oz RQZ – EMC - 1
  • EMC – RFI from unintentional transmitters
    • Industrial & domestic machinery
  • Oz - RFI from Mining activities
    • Mining equipment
    • Communications used by mines (e.g. VHF & UHF radio)
    • Infrastructure for ore transport (Rail & trucks)
  • Need limits and exclusion zones
    • Limits as per RQZ
  •  Mineral Resource Management Area

** Work with Regional authorities **

oz rqz emc 2
Oz RQZ – EMC - 2
  • Other RQZ RFI issues
    • RFI from co-located science instruments (MWA)
    • Self-generated RFI
      • Buildings; Computers; Telescope electronics
  • Must develop EMC Limits & Testing protocols
    • Base on MIL standards for testing
    • But very difficult to test to RA.769 levels
      • Correlation spectrometers
      • Radio telescope testing (e.g. at Parkes)
  • Must manage and mitigate self-RFI
summary lessons learned
Summary & lessons learned
  • RQZs important for RA – 1st step in mitigation
    • National “RQZ”s - coordination only
    • Weak enforcement
  • RQZ essential for SKA
    • Exclusion and coordination zones
    • Strong Enforcement
    • EMC controls and testing also critical
  • Lesson from Oz experience:

** Work closely with national communications administration **

** Work closely with Regional bodies and Governments *

  • ITU Question on RQZ – towards IRQZs?
    • Inputs from SKA RQZ experience
slide30

Comment on the SKA RQZ in Australia in a speech by the chairman of the Australian Communications and Media Authority: