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 EMI is 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 BACK to 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