Harvey LisztArecibo July 2005 Harvey S. Liszt NRAO, CHARLOTTESVILLE

Harvey LisztArecibo July 2005 What is it, exactly?

Harvey LisztArecibo July 2005 What is interference? Interference is unwanted signal occurring in a band which has been allocated to other uses When you observe outside the bands allocated to radio astronomy you may see intentional radiation which is someone else’s signal Inside a RA band, unwanted signal is quite likely to be generated by the observatory Interference is what happens when SM FAILS

Harvey LisztArecibo July 2005 What is an allocation Spectrum bands are allocated to ’services’ –Service = purpose or application –Most services are ‘active’ – they transmit –Radio astronomy and Earth-sensing are ‘passive’ RAS and EE-SS (passive) only listen Radar astronomy and EE-SS (active) also transmit but are distinct Concept of “use” elusive for passive services –FCC considers spectrum “unused” just where we work best

Examples of services Radiolocation = radar Radionavigation Radio Navigation Satellite Service = GPS Fixed service (terrestrial point to point) Fixed-satellite service (space-earth, earth-space) –terminals on 7-11’s, home satellite internet Mobile-satellite service (satellite phones) Broadcasting (TV) – known as the BS Harvey LisztArecibo July 2005

What kind of service is RAS? 1.5 radio waves or hertzian waves: Electromagnetic waves of frequencies arbitrarily lower than GHz, propagated in space without artificial guide. [Radio extends to 100  1.6radiocommunication: Telecommunication by means of radio waves. 1.7terrestrial radiocommunication: Any radio- communication other than space radiocommunication or radio astronomy radio astronomy: Astronomy based on the reception of radio waves of cosmic origin. [THESE ARE FROM THE RADIO REGULATIONS] Harvey LisztArecibo July 2005

How does RAS operate? 1.16 allocation (of a frequency band): Entry in the Table of Frequency Allocations of a given frequency band for the purpose of its use by one or more terrestrial or space radiocommunication services or the radio astronomy service under specified conditions. This term shall also be applied to the frequency band concerned. Harvey LisztArecibo July 2005

How does RAS operate? 1.16 allocation (of a frequency band): Entry in the Table of Frequency Allocations of a given frequency band for the purpose of its use by one or more terrestrial or space radiocommunication services or the radio astronomy service under specified conditions. This term shall also be applied to the frequency band concerned. 4.6 For the purpose of resolving cases of harmful interference, the radio astronomy service shall be treated as a radiocommunication service. However, protection from services in other bands shall be afforded the radio astronomy service only to the extent that such services are afforded protection from each other. Harvey LisztArecibo July 2005

How does RAS operate? 1.16 allocation (of a frequency band): Entry in the Table of Frequency Allocations of a given frequency band for the purpose of its use by one or more terrestrial or space radiocommunication services or the radio astronomy service under specified conditions. This term shall also be applied to the frequency band concerned. 4.6 For the purpose of resolving cases of harmful interference, the radio astronomy service shall be treated as a radiocommunication service. However, protection from services in other bands shall be afforded the radio astronomy service only to the extent that such services are afforded protection from each other. Bottom line: RAS has standing only to the extent that it may experience interference, which can only happen inside RAS bands, so having allocations is necessary to participation in spectrum management Harvey LisztArecibo July 2005

4.4 Administrations of the Member States shall not assign to a station any frequency in derogation of either the Table of Frequency Allocations in this Chapter or the other provisions of these Regulations, except on the express condition that such a station, when using such a frequency assignment, shall not cause harmful interference to, and shall not claim protection from harmful interference caused by, a station operating in accordance with the provisions of the Constitution, the Convention and these Regulations Harvey LisztArecibo July 2005 How does RAS operate?

4.4 Administrations of the Member States shall not assign to a station any frequency in derogation of either the Table of Frequency Allocations in this Chapter or the other provisions of these Regulations, except on the express condition that such a station, when using such a frequency assignment, shall not cause harmful interference to, and shall not claim protection from harmful interference caused by, a station operating in accordance with the provisions of the Constitution, the Convention and these Regulations Bottom line: RAS is free to observe in any band but may cry “foul” only when there is ‘harmful interference’ to RAS in RAS bands. Harvey LisztArecibo July 2005 How does RAS operate?

RAS is Unique Harvey LisztArecibo July 2005

Harvey LisztArecibo July 2005 The world is flat– ITU-R Regions

Harvey LisztArecibo July 2005 Part of the FCC version of the frequency table

Harvey LisztArecibo July 2005 Part of the FCC version of the frequency table

Harvey LisztArecibo July 2005 Part of the FCC version of the frequency table

Harvey LisztArecibo July 2005 Part of the FCC version of the frequency table

Harvey LisztArecibo July 2005 Part of the FCC version of the frequency table

Harvey LisztArecibo July 2005 Deconstruction

Harvey LisztArecibo July 2005 Deconstruction

Harvey LisztArecibo July 2005

Harvey LisztArecibo July 2005

Harvey LisztArecibo July 2005 WRC00 Allocations now extend up to 275 GHZ

Harvey LisztArecibo July 2005

Some lesser protections Harvey LisztArecibo July 2005

Harvey LisztArecibo July 2005 US74 … Catch 22?

Harvey LisztArecibo July 2005 US74 FCC has considered cell phones on planes 2 nd harmonic in ‘protected’ OH commercial aircraft are in direct line of sight to GB at any moment during a typical day

That’s the status quo – what’s it to you? When you find an extraneous signal in your data, YOU can go to the frequency allocation table and see what is transmitting there! If YOU were pointing the GBT toward the geosynchronous satellite belt and searching for a H2O maser in a galaxy at z = 0.66, YOU would find that this band is used for fixed- satellite service downlinks to VSAT’s! Harvey LisztArecibo July 2005

What’s the process? All countries are sovereign inside their border –Radio waves always know where to stop, eh? But no country can operate a satellite transmitter without ITU-R permission Border issues are often important So the most general set of rules, the Radio Regulations, is an international treaty, renegotiated every 4-5 years at a UN organ. Harvey LisztArecibo July 2005

Harvey LisztArecibo July 2005 A UN agency in Geneva

Harvey LisztArecibo July 2005 A UN agency in Geneva

Harvey LisztArecibo July 2005 A UN agency in Geneva

Harvey LisztArecibo July 2005 A UN agency in Geneva

Harvey LisztArecibo July 2005 A UN agency in Geneva Entire ITU-R structure mirrored in US USWP7A,B,C,D

Harvey LisztArecibo July 2005 The world is flat-- ITU Regions

Harvey LisztArecibo July 2005 Regional Groups CITEL APT Arab group CEPT

Harvey LisztArecibo July 2005 For RAS, too citel apt Arab group cept craf rafcap corf

Harvey LisztArecibo July 2005 And the IUCAF umbrella IUCAF –ICSU-chartered for IAU, COSPAR, URSI –Historically, the vehicle for RAS representation –Now being pressured to be more interdisciplinary –

What’s hot now? RAS is bringing sensitive broadband instruments online opening new bands Some of these bands are becoming toxic –High power orbiting radars, GHz –Cloud-mapping (CloudSat GHz) –TerraSar-X earth mapping SAR at GHz –Could burn up a RAS receiver in the (statistically) unlikely event of a main-beam encounter Harvey LisztArecibo July 2005

Where will it end Our operations are being pushed back onto reservations and very out of the way places –In spectrum too, above 80 GHz is where RA has widest allocations We are creating and trying to get more recognition for Radio Quiet Zones and operation at frequencies > 275 GHz –At present, no RQZ will protect you from a satellite or airplane, however toxic. Harvey LisztArecibo July 2005

Where will it end Worrying ‘too much’ is just crazy-making –Worrying too little would be dangerous And illegal, being careful is in the Radio Regs We haven’t found effective means of mitigating unwanted emissions, except to avoid them We’re still working, despite ‘encroachments’ If we were forced into space, we’d become vastly richer overnight Harvey LisztArecibo July 2005