Radio-Quiet ZonesRadio-Quiet Zones Radio-Quiet ZonesRadio-Quiet Zones

R. J. CohenR. J. Cohen R. J. CohenR. J. Cohen

Jodrell Bank ObservatoryJodrell Bank Observatory

University of ManchesterUniversity of Manchester

Jodrell Bank ObservatoryJodrell Bank Observatory

University of ManchesterUniversity of Manchester

13th June 200213th June 200213th June 200213th June 2002

Susceptibility of Radio Astronomy Susceptibility of Radio Astronomy to Interferenceto Interference

Cosmic signals are weak Cosmic signals are weak (billions of times weaker (billions of times weaker than man-made signals) and noise-likethan man-made signals) and noise-like1 Jy = 101 Jy = 10-26 -26 W/mW/m22/Hz/Hz

Redshifts carry spectral lines to lower frequencies Redshifts carry spectral lines to lower frequencies (because of expanding Universe)(because of expanding Universe)

Harmful interference levels are very lowHarmful interference levels are very low

Results of measurements are usually unpredictable: Results of measurements are usually unpredictable: interference may look like new scienceinterference may look like new science

mm-wave receivers easily destroyed (1mm-wave receivers easily destroyed (1μμm junctions)m junctions)and filtering techniques are not matureand filtering techniques are not mature

Susceptibility of Radio Astronomy Susceptibility of Radio Astronomy to Interferenceto Interference

Cosmic signals are weak Cosmic signals are weak (billions of times weaker (billions of times weaker than man-made signals) and noise-likethan man-made signals) and noise-like1 Jy = 101 Jy = 10-26 -26 W/mW/m22/Hz/Hz

Redshifts carry spectral lines to lower frequencies Redshifts carry spectral lines to lower frequencies (because of expanding Universe)(because of expanding Universe)

Harmful interference levels are very lowHarmful interference levels are very low

Results of measurements are usually unpredictable: Results of measurements are usually unpredictable: interference may look like new scienceinterference may look like new science

mm-wave receivers easily destroyed (1mm-wave receivers easily destroyed (1μμm junctions)m junctions)and filtering techniques are not matureand filtering techniques are not mature

Effective protection of radio astronomy requires coordinated action at all levels. The threats can be global, regional, national or local.

Effective protection of radio astronomy requires coordinated action at all levels. The threats can be global, regional, national or local.

Protection for Radio Astronomy - 1

GLOBALLY - International Telecommunications Union (ITU) and Radio Regulations (quiet frequency bands for RA worldwide, limits on satellite emissions)

REGIONALLY - international agreements on harmonized spectrum use (e.g. how to share bands) and standards (good neighbours)

NATIONALLY – planning by telecommunications authority; spectrum management can create and maintain a radio-quiet zone

LOCALLY – remote site for observatory, liaise with local authorities about developments in RQZ

GLOBALLY - International Telecommunications Union (ITU) and Radio Regulations (quiet frequency bands for RA worldwide, limits on satellite emissions)

REGIONALLY - international agreements on harmonized spectrum use (e.g. how to share bands) and standards (good neighbours)

NATIONALLY – planning by telecommunications authority; spectrum management can create and maintain a radio-quiet zone

LOCALLY – remote site for observatory, liaise with local authorities about developments in RQZ

Protection for Radio Astronomy - 2

ITU-R Rec. RA.769-1 (RFI levels)

1. Radio astronomers should be encouraged to choose sites as free as possible from interference;

2. Administrations should afford all practicable protection to RA frequency bands, taking due account of the interference levels given in Annex 1;

3. Administrations should take all practicable steps to reduce unwanted emissions into RA bands, particularly from aircraft, spacecraft and balloons;

4. Administration should take into account the difficulties of sharing frequencies with transmitters in direct line-of-sight to observatories.

ITU-R Rec. RA.769-1 (RFI levels)

1. Radio astronomers should be encouraged to choose sites as free as possible from interference;

2. Administrations should afford all practicable protection to RA frequency bands, taking due account of the interference levels given in Annex 1;

3. Administrations should take all practicable steps to reduce unwanted emissions into RA bands, particularly from aircraft, spacecraft and balloons;

4. Administration should take into account the difficulties of sharing frequencies with transmitters in direct line-of-sight to observatories.

ITU-R Rec. RA.1031-1 (shared bands)

1. In making assignments administrations should take all practicable steps to avoid interference to RA; (e.g. don’t assign the frequencies to active services: shared bands don’t have to be shared!)

2. Consideration be given to protecting RA sites by establishing coordination zones; (don’t assign the frequencies within a calculated distance of the radio observatory)

3. That the size of the coordination zone be calculated taking account of the protection criteria in Rec. RA.769-1 and suitable propagation model.

ITU-R Rec. RA.1031-1 (shared bands)

1. In making assignments administrations should take all practicable steps to avoid interference to RA; (e.g. don’t assign the frequencies to active services: shared bands don’t have to be shared!)

2. Consideration be given to protecting RA sites by establishing coordination zones; (don’t assign the frequencies within a calculated distance of the radio observatory)

3. That the size of the coordination zone be calculated taking account of the protection criteria in Rec. RA.769-1 and suitable propagation model.

ITU-R Rec. RA.1272-1 (above 60 GHz)

1. Coordination zones be established around mm-wave observatories, for all frequencies above 60 GHz where practicable;

2. Until appropriate criteria are developed, use Rec RA.1031 to define size of coordination zone.

Sharing with terrestrial services is possible at mm-wavelengths because of atmospheric attenuation, shielding by topography, and since there are only a small number of remote sites to protect. Also, at present the radio astronomers are almost the only people using the bands.

ITU-R Rec. RA.1272-1 (above 60 GHz)

1. Coordination zones be established around mm-wave observatories, for all frequencies above 60 GHz where practicable;

2. Until appropriate criteria are developed, use Rec RA.1031 to define size of coordination zone.

Sharing with terrestrial services is possible at mm-wavelengths because of atmospheric attenuation, shielding by topography, and since there are only a small number of remote sites to protect. Also, at present the radio astronomers are almost the only people using the bands.

In-band transmitters: Most radio astronomy frequency bands are shared with active users (transmitters), some roaming! Need good coordination process.

Out-of-band interference: Signals can leak into passive bands (pollution); powerful transmitters can block RA receiver (including IF amplifiers, e.g. IRAM radar). Need coordination of transmitters at any frequency.

Non-radio transmitters: Electrical or electronic devices (e.g. computers, microwave ovens) – need better EMC standards

In-band transmitters: Most radio astronomy frequency bands are shared with active users (transmitters), some roaming! Need good coordination process.

Out-of-band interference: Signals can leak into passive bands (pollution); powerful transmitters can block RA receiver (including IF amplifiers, e.g. IRAM radar). Need coordination of transmitters at any frequency.

Non-radio transmitters: Electrical or electronic devices (e.g. computers, microwave ovens) – need better EMC standards

Need for Radio-Quiet Zones

Natural Radio Quiet Zones: Natural Radio Quiet Zones:

Sun-Earth Lagrangian point LSun-Earth Lagrangian point L22

Shielded zone of MoonShielded zone of Moon

Terrestrial Radio Quiet Zones:Terrestrial Radio Quiet Zones:

Typical radio observatory (Jodrell Bank)Typical radio observatory (Jodrell Bank)

Greenbank USAGreenbank USA

SKA (possible Australian site) SKA (possible Australian site)

ALMA ALMA

Natural Radio Quiet Zones: Natural Radio Quiet Zones:

Sun-Earth Lagrangian point LSun-Earth Lagrangian point L22

Shielded zone of MoonShielded zone of Moon

Terrestrial Radio Quiet Zones:Terrestrial Radio Quiet Zones:

Typical radio observatory (Jodrell Bank)Typical radio observatory (Jodrell Bank)

Greenbank USAGreenbank USA

SKA (possible Australian site) SKA (possible Australian site)

ALMA ALMA

Radio-Quiet Zones

VSA (Very Small Array)

• 14-element array at Observatorio del Teide (Tenerife)

• UK (Jodrell Bank and Cambridge) and Spanish collaboration

• maps cosmic μ-wave background at 31 GHz

• RFI screen (very small radio-quiet zone)

Lovell Telescope

• 250 ft fully steerable• Upgrade in progress• Consultation zone • Coordination zones

(per frequency band)

Direction from the Department of the Environment to Direction from the Department of the Environment to local planning authorities: 6 mile consultation local planning authorities: 6 mile consultation zone established 10 years after telescope builtzone established 10 years after telescope built

Jodrell Bank Observatory automatically consulted Jodrell Bank Observatory automatically consulted about any new buildings or developments ,about any new buildings or developments ,

within the Consultation Zone (as part of the within the Consultation Zone (as part of the normal normal planing permission process)planing permission process)

Also, UK Radiocommunications Agency provides Also, UK Radiocommunications Agency provides protection from certain radio transmitters protection from certain radio transmitters

anywhere in the UK (coordination to agreed anywhere in the UK (coordination to agreed levels depending on frequency band)levels depending on frequency band)

Direction from the Department of the Environment to Direction from the Department of the Environment to local planning authorities: 6 mile consultation local planning authorities: 6 mile consultation zone established 10 years after telescope builtzone established 10 years after telescope built

Jodrell Bank Observatory automatically consulted Jodrell Bank Observatory automatically consulted about any new buildings or developments ,about any new buildings or developments ,

within the Consultation Zone (as part of the within the Consultation Zone (as part of the normal normal planing permission process)planing permission process)

Also, UK Radiocommunications Agency provides Also, UK Radiocommunications Agency provides protection from certain radio transmitters protection from certain radio transmitters

anywhere in the UK (coordination to agreed anywhere in the UK (coordination to agreed levels depending on frequency band)levels depending on frequency band)

Jodrell Bank Consultation Zone

Act to amend the code 1931 of West Virginia, passed Act to amend the code 1931 of West Virginia, passed in August 1956, enacting zoning restrictions in August 1956, enacting zoning restrictions governing the use of electrical equipment governing the use of electrical equipment

within 10 miles of any radio astronomy facilitywithin 10 miles of any radio astronomy facility

CHAPTER 37-A. ZONING CHAPTER 37-A. ZONING Article 1. Radio Astronomy Zoning Act Article 1. Radio Astronomy Zoning Act

Within 2 miles it is illegal to operate any electrical Within 2 miles it is illegal to operate any electrical equipment that causes interferenceequipment that causes interference

Protection within 10 miles based on field strengths Protection within 10 miles based on field strengths of emissions (graded limits for equipment of emissions (graded limits for equipment

within 3,4, 5, 6, 7, 8, 9 and 10 miles)within 3,4, 5, 6, 7, 8, 9 and 10 miles)

Act to amend the code 1931 of West Virginia, passed Act to amend the code 1931 of West Virginia, passed in August 1956, enacting zoning restrictions in August 1956, enacting zoning restrictions governing the use of electrical equipment governing the use of electrical equipment

within 10 miles of any radio astronomy facilitywithin 10 miles of any radio astronomy facility

CHAPTER 37-A. ZONING CHAPTER 37-A. ZONING Article 1. Radio Astronomy Zoning Act Article 1. Radio Astronomy Zoning Act

Within 2 miles it is illegal to operate any electrical Within 2 miles it is illegal to operate any electrical equipment that causes interferenceequipment that causes interference

Protection within 10 miles based on field strengths Protection within 10 miles based on field strengths of emissions (graded limits for equipment of emissions (graded limits for equipment

within 3,4, 5, 6, 7, 8, 9 and 10 miles)within 3,4, 5, 6, 7, 8, 9 and 10 miles)

Greenbank Radio-Quiet Zone - 1

National Radio Quiet Zone established with FCC rule National Radio Quiet Zone established with FCC rule making document No. 11745, Nov 1958making document No. 11745, Nov 1958

13,000 square miles of Virginia and West Virginia13,000 square miles of Virginia and West Virginia

NRAO automatically consulted about new radio NRAO automatically consulted about new radio transmitters within the Radio-Quiet Zone (as transmitters within the Radio-Quiet Zone (as part of the normal licencing process)part of the normal licencing process)

If an ERP limit is not acceptable to the applicant, If an ERP limit is not acceptable to the applicant, NRAO will assist in finding a mutually NRAO will assist in finding a mutually

acceptable alternativeacceptable alternative

The laws were set up before the radio telescopes The laws were set up before the radio telescopes and before any frequency allocations to RASand before any frequency allocations to RAS

National Radio Quiet Zone established with FCC rule National Radio Quiet Zone established with FCC rule making document No. 11745, Nov 1958making document No. 11745, Nov 1958

13,000 square miles of Virginia and West Virginia13,000 square miles of Virginia and West Virginia

NRAO automatically consulted about new radio NRAO automatically consulted about new radio transmitters within the Radio-Quiet Zone (as transmitters within the Radio-Quiet Zone (as part of the normal licencing process)part of the normal licencing process)

If an ERP limit is not acceptable to the applicant, If an ERP limit is not acceptable to the applicant, NRAO will assist in finding a mutually NRAO will assist in finding a mutually

acceptable alternativeacceptable alternative

The laws were set up before the radio telescopes The laws were set up before the radio telescopes and before any frequency allocations to RASand before any frequency allocations to RAS

Greenbank Radio-Quiet Zone - 2

ALMA and mm-wave AstronomyALMA and mm-wave Astronomy

The global situation is very good since WRC-2000.The global situation is very good since WRC-2000.

Generous allocations above 71 GHz for passive Generous allocations above 71 GHz for passive services (24% of spectrum to remain passive and a services (24% of spectrum to remain passive and a further 43% allocated to radio astronomy on primary further 43% allocated to radio astronomy on primary basis). basis). Most useable frequencies can be protected.Most useable frequencies can be protected.

Radio astronomy use of frequencies up to 1 THz is Radio astronomy use of frequencies up to 1 THz is now officially acknowledge through Footnote S5.565.now officially acknowledge through Footnote S5.565.

Frequency allocations above 275 GHz are on the Frequency allocations above 275 GHz are on the agenda for WRC-2006.agenda for WRC-2006.

First regulatory limits on unwanted emissions from First regulatory limits on unwanted emissions from satellites.satellites.

ALMA and mm-wave AstronomyALMA and mm-wave Astronomy

The global situation is very good since WRC-2000.The global situation is very good since WRC-2000.

Generous allocations above 71 GHz for passive Generous allocations above 71 GHz for passive services (24% of spectrum to remain passive and a services (24% of spectrum to remain passive and a further 43% allocated to radio astronomy on primary further 43% allocated to radio astronomy on primary basis). basis). Most useable frequencies can be protected.Most useable frequencies can be protected.

Radio astronomy use of frequencies up to 1 THz is Radio astronomy use of frequencies up to 1 THz is now officially acknowledge through Footnote S5.565.now officially acknowledge through Footnote S5.565.

Frequency allocations above 275 GHz are on the Frequency allocations above 275 GHz are on the agenda for WRC-2006.agenda for WRC-2006.

First regulatory limits on unwanted emissions from First regulatory limits on unwanted emissions from satellites.satellites.

International frequency allocations for ALMA are International frequency allocations for ALMA are very favourable, but need careful very favourable, but need careful

implementation when frequencies are assigned implementation when frequencies are assigned nationally (and regionally harmonized).nationally (and regionally harmonized).

Any electrical equipment can cause interference, not Any electrical equipment can cause interference, not just radio transmitters, so need to involve local just radio transmitters, so need to involve local planning authorities as well as national planning authorities as well as national

telecommunications authority.telecommunications authority.

ALMA Radio-Quiet Zone needs to be set up as soon ALMA Radio-Quiet Zone needs to be set up as soon as possible. as possible.

International frequency allocations for ALMA are International frequency allocations for ALMA are very favourable, but need careful very favourable, but need careful

implementation when frequencies are assigned implementation when frequencies are assigned nationally (and regionally harmonized).nationally (and regionally harmonized).

Any electrical equipment can cause interference, not Any electrical equipment can cause interference, not just radio transmitters, so need to involve local just radio transmitters, so need to involve local planning authorities as well as national planning authorities as well as national

telecommunications authority.telecommunications authority.

ALMA Radio-Quiet Zone needs to be set up as soon ALMA Radio-Quiet Zone needs to be set up as soon as possible. as possible.

ALMA Radio-Quiet Zone

Earth from Space:Earth from Space: Forte satellite,Forte satellite, 131 MHz131 MHz

Consortium aims to select a site by 2005.Consortium aims to select a site by 2005.

Measurement programmes underway in China, Measurement programmes underway in China, inland Australia and elsewhere (0-2 GHz). inland Australia and elsewhere (0-2 GHz).

Investigating option to have main building and Investigating option to have main building and astronomers away from telescope (optical fibre astronomers away from telescope (optical fibre connection).connection).

OECD Task Force on Radio Astronomy is OECD Task Force on Radio Astronomy is investigating ways to establish an investigating ways to establish an internationally internationally recognized radio-quiet zone, and recognized radio-quiet zone, and ways to deal ways to deal with satellites.with satellites.

Tasso Tzioumis will say more.Tasso Tzioumis will say more.

Consortium aims to select a site by 2005.Consortium aims to select a site by 2005.

Measurement programmes underway in China, Measurement programmes underway in China, inland Australia and elsewhere (0-2 GHz). inland Australia and elsewhere (0-2 GHz).

Investigating option to have main building and Investigating option to have main building and astronomers away from telescope (optical fibre astronomers away from telescope (optical fibre connection).connection).

OECD Task Force on Radio Astronomy is OECD Task Force on Radio Astronomy is investigating ways to establish an investigating ways to establish an internationally internationally recognized radio-quiet zone, and recognized radio-quiet zone, and ways to deal ways to deal with satellites.with satellites.

Tasso Tzioumis will say more.Tasso Tzioumis will say more.

Square Kilometre Array