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JTA-3: EM-ambient site survey of industrial environments

JTA-3: EM-ambient site survey of industrial environments. Frank Leferink. Basis. Background: Data Beauvois-Catrysse ITU-R P.372-8: Radio Noise ERC Report 69: Propagation Model and Interference Range Calculation For Inductive Systems 10 kHz - 30 MHz (Marbella, February 1999)

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JTA-3: EM-ambient site survey of industrial environments

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  1. JTA-3: EM-ambient site survey of industrial environments Frank Leferink Workshop COST 286, Barcelona, april 2005

  2. Basis • Background: • Data Beauvois-Catrysse • ITU-R P.372-8: Radio Noise • ERC Report 69: Propagation Model and Interference Range Calculation For Inductive Systems 10 kHz - 30 MHz (Marbella, February 1999) • CIGRE 36.04: Guide on EMC in Power Plants and Substations • ITU 61 WG document • IEC 61000-2 environments • CENELEC CLC/TS 50217 (2004-04): Guide for in situ measurements – In situ measurement of Disturbance emission • and: • RA(OfCom) AY 3952: Feasibility Study into the Measurement of Man-Made Noise (2001) • RA(OfCom) AY4119: Man-Made Noise Measurement Programme (2003) Workshop COST 286, Barcelona

  3. RA(OfCom) report AY 3952 • OfCom report summary: • There is a limited amount of information regarding man-made noise data. Unfortunately, it was either recorded before digital systems were deployed, or at limited bandwidths and at frequencies below 900MHz. • The currently available models (ITU or other) have value but are likely not to be sufficient for digital modulation methods. • There is a need to produce models, representative of current environmental conditions, and with appropriate bandwidths (and therefore time-resolutions) commensurate with current technology. These may be used to define a basis for system planning and design. The establishment of a firm baseline for such models now will enable future changes in the environment to be detected and the spectrum to be utilised more effectively. Workshop COST 286, Barcelona

  4. RA(OfCom) report AY 4119 • Man Made Noise (MMN): • White Gaussian Noise (WGN) and • Impulsive Noise (IN), most of it is Class B noise, typically made up of very short impulses that are very wideband and are frequently man-made in origin. The class includes impulses from automotive ignition circuits, thermostats, lighting, etc. • Measurements cumbersome: fixed frequency and sampling the IF • Dedicated to establishing the noise floor for services Workshop COST 286, Barcelona

  5. RA(OfCom) report AY 4119 • Conclusion (one of many): • The mean values of Fa observed during this study appear significantly higher than the median values given in [P.372]. The best explanation available for this is that the number of electronic and electrical devices has grown dramatically in the UK over the past few decades. Whilst EMC legislation has suppressed the IN emissions from automotive sources, there is a general background of WGN that is possibly caused by the incoherent summation of the radiation from hundreds of pieces of equipment. If so, then this is an important finding that should be verified by further tests. Workshop COST 286, Barcelona

  6. RA(OfCom) report AY 4119 Workshop COST 286, Barcelona

  7. Experiments in The Netherlands • From a Thales report 1999: The noise levels and resulting radiated emission levels presented in Figure 2 are based on the studies performed around 1960. Comparing these levels with our measurement results obtained in nowadays urban and suburban environments in 1997 and 1999 we can observe an increase of approximately 20dB. Workshop COST 286, Barcelona

  8. CCIR rep. 1963, levels converted to field strength Workshop COST 286, Barcelona

  9. premises Signaal, 10:00, dec 1999 Workshop COST 286, Barcelona

  10. Measurements, 1 • To establish noise floor for services: fixed frequency, and measure IF (APD) • EMI: scan of whole spectrum needed • Frequency spectrum: • 30 Hz - 10 kHz • 9 kHz - 150 kHz • 150 kHz - 30 MHz • 30 MHz - 1 GHz • 1 GHz - 12 GHz receiver computer ADC Workshop COST 286, Barcelona

  11. Measurements, 2 • Antennas: no directional but omni (preferred) • 9 kHz – 30 MHz: 60 cm diameter loop antennas such as the R&S HFH-2 or the Electro-metrics ALP • 30 MHz – 1 GHz: bicon and log periodic, or bilog/biconilog, or active • 1 GHz – 12 GHz: preferred: omni (Singer CLS), otherwise double ridged guide, log spiral or horn • Bandwidth: • 10 Hz – 1 kHz: 10 Hz • 1 kHz – 10 kHz: 100 Hz • 9 kHz – 150 kHz: 1 kHz (CISPR: 200 Hz) • 150 kHz – 30 MHz: 10 kHz (CISPR: 10 kHz) • 30 MHz – 1 GHz: 100 kHz (CISPR: 120 kHz) • 1 GHz – 10 GHz: 1 MHz Workshop COST 286, Barcelona

  12. Measurements, 3 • Detector: • Peak and average (parallel preferred). If only one: peak • Measuring time: • > 10*1/BW (example: BW=100 Hz, 10*10=100 ms) • overnight measurements: >100ms • Stepsize: • ≤ 0.8 * BW (prefered: 0.8 * BW) • Reference measurement: • 50 W load on receiver • Active antenna: inside a closed anechoic chamber Workshop COST 286, Barcelona

  13. Measurements, 4 • Measurements: • 10 times, in one week, at different times of a 24 hour day (prefered) • Measurement positions: • At 10 m distance from equipment • At 10 m outside building • Make pictures and drawings • Data format: • File for every measurement, in ASCII, 2 columns: frequency and level and the unit for the measurement (dbmA (current probe), dbmV (LISN), dBmA/m (H), dBmV/m (E)) Workshop COST 286, Barcelona

  14. Test plan???? • Students • Test equipment • Car • But clean power? Static converter in a faraday box? Workshop COST 286, Barcelona

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