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Monitoring EMI and the radio spectrum in Europe. Titus Spoelstra CRAF. Monitoring. Before starting: What is the question you want to answer? ( avoid collection of large amounts of data ) Harmonize data format and analysis tools to ease exchange of information
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Monitoring EMI and the radio spectrum in Europe Titus Spoelstra CRAF
Monitoring • Before starting: What is the question you want to answer? (avoid collection of large amounts of data) • Harmonize data format and analysis tools to ease exchange of information • Monitoring spectrum occupancy is not EMI/RFI monitoring
Electromagnetic Interference (EMI) • The effect of unwanted energy due to one or a combination of emissions, radiations, or inductions upon reception in a radiocommunication system, or loss of information which could be extracted in the absence of such unwanted energy
Electromagnetic Interference (EMI) • EMI: ‘quantification’ of degradation of the quality of an observation due to unwanted emissions, radiations, or inductions upon reception in a radiocommunication system • Information about EMIis obtained by inspection of observations
Spectrum occupancy • Spectrum occupancy information identifies the chance to become victim of interference • This info is e.g. a scheduling tool to avoid EMI • Monitoring spectrum occupancy done by dedicated instruments
RAS Monitoring facilities in Europe • Half a dozen of EVN stations operate facilities to monitor spectrum occupancy • In addition several radio astronomy observatories have their own specific facilities (e.g. omni-directional antenna with receiver – fixed or mobile facility) • Information usually kept in house: “all data are stored”
CRAF database for EMI and spectrum occupancy • Facility for all European radio astronomy stations managed by the CRAF clearing house in Dwingeloo and accessible via CRAF website • Dataflow in ‘CRAF data-format’ to Dwingeloo • Range of analysis tools for both EMI and spectrum occupancy
CRAF EMI DatabaseQuery Facility • Query options to the CRAF EMI database: • (select item by clicking on the option or BACK to previous page) • Interference intensity as a function of time of the day • Interference intensity as a function of days of the week • Interference intensity as a function of frequency • Development of interference intensity as a function of time • Observation degradation as a function of time of the day • Observation degradation as a function of days of the week • Observation degradation as a function of frequency • Development of observation degradation as a function of time • Interference occurrence as a function of time of the day • Interference occurrence as a function of days of the week • Interference occurrence as a function of frequency • Development of interference occurrence as a function of time • Last modified: August 8, 2001
CRAF SPECTRUM OCCUPANCY DatabaseQuery Facility • Query options to the CRAF SPECTRUM OCCUPANCY database: • (select item by clicking on the option or BACKto previous page) • Signal intensity as a function of time of the day • Signal intensity as a function of days of the week • Signal intensity as a function of frequency • Development of signal intensity as a function of time • Signal occurrence as a function of time of the day • Signal occurrence as a function of days of the week • Signal occurrence as a function of frequency • Development of signal occurrence as a function of time • Last modified: August 8, 2001
Use of information • Quantified evidence for Administrations in case of trouble. NOTE: if interference is not reported to Administrations, interference does not exist! • Monitor the development of the EMI “climatology” (relevant in communication with Administrations). • Improve observation conditions at the station • Specific projects: e.g. development of interference-robust receivers, interference suppression techniques
CRAF facility • Username and password required, because: In many countries it is strictly forbidden to monitor spectrum occupancy or to ‘publish’ monitoring data.
National developments • In some countries increased Administrative monitoring effort • The Netherlands: cooperation between Administration and RAS on exchange of information
CEPT • Stations: several for terrestrial services; for satellite monitoring: Leeheim (Germany) • Improvement of monitoring effort in Europe: - MoU between CEPT Administrations - Further development of German Leeheim Satellite monitoring station into European satellite monitoring facility funded by CEPT countries