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Radio Quiet Zones (RQZ) - working with your national administration. Tasso Tzioumis Australia Telescope National Facility (ATNF) [email protected] .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)

[email protected] .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


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 Act

  • Studies & definition by ACMA & CSIRO

  • RALI MS32 - in force since 24/9/2007


Oz rqz procedures
Oz RQZ procedures Act

  • From RALI MS32


Oz rqz emc 1
Oz RQZ Act– 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 Act– 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 Act

  • 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


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


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