An evaluation of local interferences in the 0-3 GHz band An evaluation of local interferences in the 0-3 GHz band. A case study in Meco (Spain) Natalia Cañadilla Fernández, Pablo Luis López Espí and Rocío Sánchez Montero University of Alcalá Detection and measurement of RFI in radio astronomy, Yebes Observatory, 8-9 June, 2017

Topics Introduction Broadband RFI Characterization Measurement protocol Broadband Measured Values Narrowband Measured Values Conclusions Detection and measurement of RFI in radio astronomy, Yebes Observatory, 8-9 June, 2017

Introduction VGOS Project BRAND Project From S band 2,2 – 2.37 GHz (170 MHz) and X Band (8.1-8.9 GHz) to ultra-wideband from 2 to 14 GHz. VGOS receiver was installed at Yebes in 2016. RFI was a great problem to deal with due to fibber links saturation. BRAND Project One of the objectives is to design a broadband receiver from 1.5 GHz to 15.5 GHz Many RFI problems are expected. Must be taken into account in the receiver design. Detection and measurement of RFI in radio astronomy, Yebes Observatory, 8-9 June, 2017

Broadband RFI Characterization An idea about RFI levels may be broadband exposure limits Electromagnetic radiowave exposure is a major concern in most countries due to possible adverse health effects. Usually, local regulations follow the guidelines of the International Commission on Non-Ionizing Radiation Protection (ICNIRP) (ICNIRP, 1998). The International Telecommunications Union (ITU) has published several recommendations about measurements, protocols and technical standards related to EMF emissions and protection. Recommendation ITU-T K.61, ITU-T K-83, ITU-T K.100 and ITU-T K.113. The number of mobile telephony base transceiver stations (BTS) in Spain has doubled in the period 2006-2015. Other sources must be taken into account: WiFi, Wimax, TV…   2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 GSM900 24,998 26,850 27,869 28,255 31,582 34,817 38,121 40,918 42,408 43,590 DCS1800 20,178 21,290 22,780 23,285 21,639 21,242 21,761 20,949 19,978 19,324 UMTS 16,921 22,874 27,382 31,304 34,324 42,474 46,281 45,273 47,260 51,786 LTE 5,649 14,654 23,801 Total 62,097 71,014 78,031 82,844 87,545 98,533 106,163 112,789 124,300 138,501 Number of mobile base stations in Spain. Source: National Commission for Markets and Competency. Detection and measurement of RFI in radio astronomy, Yebes Observatory, 8-9 June, 2017

Measurement Protocol Broadband measurement is the optimal solution (from an exposure point of view) for a large number of measurements in a wide area involving various sources (from various locations) or a single source with various frequencies, because it is not as expensive as narrowband measurement and gives a value of the total electric field in that specific point. ICNIRP recommends 6 minute averaging. FM (88-108 MHz), DAB (174-223), TETRA (380-400), DVB-T/TV (470-830), GSM900 (UL 880-915 DL 925-960), GSM1800 (UL 1710-1785 DL 1805-1880) DECT (1880-1900) UMTS (UL 1920-1980 DL 2110-2170) LTE800 (DL 791-821 UL 832-862), LTE 1800 (DL 1805-1880 UL 1710-1785) LTE2600 (DL 2620-2690 UL 2500-2570) and WIFI 2G (2400-2500). Detection and measurement of RFI in radio astronomy, Yebes Observatory, 8-9 June, 2017

Valor de la Intensidad de Campo Eléctrico (V/m) Measured Values   Valor de la Intensidad de Campo Eléctrico (V/m) Emáx (V/m) Emín (V/m) Mean Std. Dev Alcalá de Henares 2010 (Morning) 2,12 0,06 0,41 0,33 Alcalá de Henares 2010 (Evening) 1,97 0,03 0,40 0,35 Alcalá de Henares 2006 1,24 0,02 0,19 0,16 Campus UAH 2005 (Morning) 0,87 0,07 0,17 0,10 Campus UAH 2005 (Evening) 0,94 0,08 0,21 0,11 Campus UAH 2006 0,57 0,13 Campus UAH 2010 0,67 0,14 0,24 Torrejón de Ardoz 1,75 0,09 0,55 0,39 Basauri 2,44 0,77 0,47 Tudela 0,90 0,01

Measured Values (Alcala de Henares) Detection and measurement of RFI in radio astronomy, Yebes Observatory, 8-9 June, 2017

Measured Values 0.2 0.4 0.6 0.8 1.0 1.2 Electric Field (V/m) 1 Cumulative probability □ 2006 + 2010 ○ 2015 Detection and measurement of RFI in radio astronomy, Yebes Observatory, 8-9 June, 2017

Measured Values Detection and measurement of RFI in radio astronomy, Yebes Observatory, 8-9 June, 2017

Measured Values Detection and measurement of RFI in radio astronomy, Yebes Observatory, 8-9 June, 2017

Non Urban Environments (Meco) Red: BTS, White: Broadband Measures, Blue: Narrowband Measures Detection and measurement of RFI in radio astronomy, Yebes Observatory, 8-9 June, 2017

Non Urban Environments (Meco) (V/m) Total Non Urban Max 1,9 1 Min 0,032 0,032 Mean 0,237 0,207 Std. Dev 0,242 0,170 Detection and measurement of RFI in radio astronomy, Yebes Observatory, 8-9 June, 2017

Narrowband Measurements Detection and measurement of RFI in radio astronomy, Yebes Observatory, 8-9 June, 2017

Narrowband Measurements Point 66 (Urban) BTS Line of sight Highest Broadband Value Measured Power (dBm) Over 50 Ohm Blue: Horizontal Pol. Red: Vertical Pol. Max Hold over 2 min Detection and measurement of RFI in radio astronomy, Yebes Observatory, 8-9 June, 2017

Narrowband Measurements Point 117 (Non Urban) Top of the hill Measured Power (dBm) Over 50 Ohm Blue: Horizontal Pol. Red: Vertical Pol. Max Hold over 2 min Detection and measurement of RFI in radio astronomy, Yebes Observatory, 8-9 June, 2017

Narrowband Measurements Point 133 (Non Urban) Lowest sea level Lowest Broadband Level Measured Power (dBm) Over 50 Ohm Blue: Horizontal Pol. Red: Vertical Pol. Max Hold over 2 min Detection and measurement of RFI in radio astronomy, Yebes Observatory, 8-9 June, 2017

Conclusions Electric Field Values show great time (short term and long term) and space variations. Broadband measurement gives a value of the total electric field in that specific point. Adv: Fast, less time consuming, easy to plot, easy to track. Narrowband measurement gives full details about frequency variation. Adv: Frequency and polarization information. Local values show great variability, a customized study is necessary for each location. Detection and measurement of RFI in radio astronomy, Yebes Observatory, 8-9 June, 2017