Luc Haeberlé Colibrex GmbH / LS telcom AG, Germany

Transcription

1 Airborne measurement for State-of-the-Art Acceptance Testing and Verification of Broadcasting Sites Luc Haeberlé Colibrex GmbH / LS telcom AG, Germany ANNUAL MEETING OF REGIONAL BROADCASTING ORGANIZATIONS AND TRANSMITTING EQUIPMENT MANUFACTURERS Timisoara, May 22 nd, Colibrex GmbH Airborne Measurement Services 1

2 Content Trends regarding terrestrial broadcasting and network monitoring Purposes of RF monitoring and antenna pattern verification Examples of coverage perturbations due to faulty antennas New possibilities of airborne measurement via Remotely Piloted Aircraft Conclusion 2013 Colibrex GmbH Airborne Measurement System 2

3 About Colibrex 100% subsidiary of LS telcom AG Colibrex offers specific services to facilitate the implementation, operation, maintenance and testing of wireless networks Main activities are Airborne Measurement Services Container Solutions & System Integration Other products & Services on request / in future? * based on cooperation and ressources within the LS telcom group of companies, especially LSofSA Main target sectors are Broadcast Operators - MNOs Regulatory bodies Specific industrial sectors having RF issues to be investigated 2013 Colibrex GmbH Airborne Measurement System 3

4 Trends on Terrestrial Broadcasting Terrestrial broadcasting is growing worldwide, despite decreasing interest in some countries due to stronger penetration of other distribution systems (cable/sat/iptv) Frequency efficiency is becoming an ultimate target both in terms of technology development and spectrum management (incl. digital dividend) Request for deeper monitoring and verification overall in the transmission chain Digital broadcasting often means complex encoding and multiplexing and more programs to be transmitted within one RF channel SFN network architectures request fine network planning and well adjusted transmission systems Digital broadcasting has liberalised the market in many countries, creating more competition on the air 2013 Colibrex GmbH Airborne Measurement System 4

5 Example of Network Architecture Monitoring / Verification RF1 Studio 1 TX2 Studio 2 Data server Contribution network MUX #1 MUX #2 MUX #3 Playout Center T2 Gateway T2-MI Distribution network (Microwave, fiber cable) RF1 TX Colibrex GmbH Airborne Measurement System 5

6 How to Measure Off-Air Signals Ground measurements offer fruitful indications about the transmitted signal, but have some critical limitations Reflections from the ground Only at selected points / limited areas (iterations necessary) not adapted to exactly determine antenna patterns and corresponding coverage The role of antennas in the transmission network and coverage achievement is predominant Wrong designed antennas or simply faulty antennas (for ex. due to wrong installation) can conduct to serious perturbations in a network 2013 Colibrex GmbH Airborne Measurement System 6

7 Example I of Installation Mistake* Looks not so bad, but * installation mistakes may happen if antennas are installed by unskilled installation companies Offset is to the wrong side! 2013 Colibrex GmbH Airborne Measurement System 7

8 Example I of Installation Mistake Wanted HRP with correctly installed side offset Totally distorted HRP because of wrong installed side offset (to opposite side) 2013 Colibrex GmbH Airborne Measurement System 8

9 Example I of Installation Mistake: Consequence in Coverage (Simulation) Wanted HRP Distorted HRP Loss: - about inhabitants - about 950 sqkm 2013 Colibrex GmbH Airborne Measurement System 9

10 Example II of Installation Mistake* Antenna Systems with Half Antenna Configuration require adjusted length of the main feeder cables often with equal length, i.e. phase difference 0 Installation mistake: Wrong main feeder length equalisation Ant L2 = L1? 1.5 meter difference means 180 degree phase at 100 MHz Circumference L = πr Tx * installation mistakes may happen if antennas are installed by unskilled installation companies 2013 Colibrex GmbH Airborne Measurement System 10

11 Example II of Installation Mistake Wanted VRP with correctly adjusted main feeder lengths Totally distorted VRP because of wrong adjustment of main feeder lengths (phase difference 180 ) 2013 Colibrex GmbH Airborne Measurement System 11

12 Example II of Installation Mistake: Consequence in Coverage (Simulation) Wanted VRP Distorted HRP Loss: - about inhabitants - about sqkm 2013 Colibrex GmbH Airborne Measurement System 12

13 Example III of Antenna Problem: Consequence in Coverage (Simulation) Assumption: Loss of 2 db gain Loss: - about inhabitants - about 900 sqkm 2013 Colibrex GmbH Airborne Measurement System 13

14 Lesson? Antenna radiation characteristics of the broadcasting antennas should be verified First after initial installation When modifications are performed After a certain time of use But how to qualify them and to test their characteristics? The only solution is to perform a measurement on air Some broadcasters have been doing such kind of airborne measurement by using conventional helicopter Expensive solution, not everywhere possible Difficult to achieve a good accuracy The development of drones or remotely piloted aircrafts offer new possibilities to realize highly accurate airborne measurements 2013 Colibrex GmbH Airborne Measurement System 14

15 Principles of RPA Airborne Measurement Use of a Remotely Piloted Aircraft (RPA) specially adapted with dedicated measurement sensor & data processor (incl. real-time download) high resolution flight positioning and orientation autopilot capabilities calibrated measuring antennas specific software for data analysis specific RF shielding 2013 Colibrex GmbH Airborne Measurement System 15

16 Applications for Broadcasters Radiating antenna patterns measurement Absolute ERP and antenna gain Photographic/video records of mast occupancy Quality of installations photo/video records Mast and equipment maintenance status survey Propagation modelling General RF measurements Such applications also apply for further operators of radio communications systems 2013 Colibrex GmbH Airborne Measurement System 16

17 Example of Measurement Report DVB-T2 Radiation patterns Antenna Pattern - Horizontal Channel 29 Horizontal (Theoretical on 140 degrees) Red Green Measured Theoretical 2013 Colibrex GmbH Airborne Measurement System 17

18 Example DVB-T 778MHz 100kW ERP (3,8 kw TX) 2013 Colibrex GmbH Airborne Measurement System 18

19 Example DVB-T 100kW ERP 4 Frequenzen 2013 Colibrex GmbH Airborne Measurement System 19

20 Example DVB-T2 New Installation 2013 Colibrex GmbH Airborne Measurement System 20

21 Example of Measurement Report Frequency (MHz) Parameter Value Unit Vertical Beam Tilt 1.00 Degrees (Positive is down tilt) Null Fill Yes Yes/No Absolute ERP kw Vertical Beam Tilt 1.00 Degrees (Positive is down tilt) Null Fill Yes Yes/No Absolute ERP kw 2013 Colibrex GmbH Airborne Measurement System 21

22 High Reproducability of the Measurements Measurements done at Kameeldrift Pretoria, South Africa ERP (theo) FREQUENCY Service : 70 kw : 738 MHz : DVB-T2 MEASUREMENT SETTINGS: RBW : Detector : RMS Attenuator : Colibrex GmbH Airborne Measurement System 22

23 Example of Measurement Flight 2013 Colibrex GmbH Airborne Measurement System 23

24 Additional Benefits: Mast and Antenna Inventory Audits Mast space occupancy Quality of installations Maintenance inspections 2013 Colibrex GmbH Airborne Measurement System 24

25 Mast and Antenna Inventory Audits 2013 Colibrex GmbH Airborne Measurement System 25

26 Conclusion Off-air measurements and especially antenna pattern measurements are essential to determine the true on site radiation characteristics of a broadcasting site and their consequences in terms of coverage Airborne measurements have often been neglected or limited to big sites only, due to the difficulties and costs to realize them with convential helicopter Remotely Piloted Aircrafts offer new possibilities to perform such measurements in a more flexible way, with a much better accuracy and at a lower cost. And it is green as its operates electricaly Airborne measurement does not only interest the operators as necessary verification / maintenance tool: the regulators might also us it to control more often if the granted licensed are respected by the broadcasters Do not forget: all the costs engaged in a complete broadcast chain can be easily wasted if the targeted coverage is not achieved Colibrex GmbH Airborne Measurement System 26

27 Thank you for your attention! Luc Haeberlé Managing Director Colibrex Colibrex GmbH Airborne Measurement System 27

28 Disclaimer Copyright (c) 2014 by Colibrex GmbH This document must neither be copied wholly or partly, nor published or re-sold without prior written permission of Colibrex. The information contained in this document is proprietary to Colibrex. The information shall only serve for documentation purposes or as support for education and training purposes and for the operation and maintenance of Colibrex products. It must be treated strictly confidential and must neither be disclosed to any third party nor be used for other purposes, e.g. software development, without the written consent of Colibrex. This document may contain product names, e. g. MS Windows, MS Word, MS Excel and MS Access, which are protected by copyright or registered trademarks / brand names in favour of their respective owners. Colibrex make no warranty or representation relating to this document and the information contained herein. Colibrex are not responsible for any costs incurred as a result of the use of this document and the information contained herein, including but not limited to, lost profits or revenue, loss of data, costs of recreating data, the cost of any substitute equipment or program, or claims by any third party Colibrex GmbH Airborne Measurement System 28