1. dTR/H&D Joint Venture1 Radio Frequency Exposure and Compliance Issues for a Shortwave May 2008 Matthew W. Folkert, MSEEE Stephen S. Lockwood, P.E. dTR/H&D Joint Venture A Joint Venture of the Consulting Engineering firms of duTreil Lundin & Rackley and Hatfield & Dawson

2. dTR/H&D Joint Venture2 HCJB - Pifo, Equador

3. dTR/H&D Joint Venture3 HCJB - Pifo, Equador

4. dTR/H&D Joint Venture Presentation Outline Scope of Work Exposure Standards Analytical Work Measurement Program Findings

5. dTR/H&D Joint Venture Scope of Work Conduct a Maximum Permissible Exposure Evaluation (MPE) of All IBB Transmitting Facilities – 16 Shortwave and Mediumwave Stations Worldwide – Limited to a Survey Safety Seminar and Plan

6. dTR/H&D Joint Venture IBB Stations Worldwide

7. dTR/H&D Joint Venture Schedule of Site Visits Delano - 1998 Greenville – 2001 Kavala, Rhodes & Kuwait - 2001 Morocco - 2002 Sao Tome - 2002 Philippines - 2003 Botswana - 2003 Sri Lanka - 2005 Germany – 2006 Tinian - 2007 Thailand - 2008

8. dTR/H&D Joint Venture Analytical Work Modeling Using NEC-2 Curtain Antennas with Full Reflecting Screen Rhombic Antennas E and H Field 2 Meters Above Ground

9. dTR/H&D Joint Venture Curtain Antenna : E-Field

10. dTR/H&D Joint Venture Curtain Antenna : H-Field

11. dTR/H&D Joint Venture Exposure Standards IEEE – C95.1-2005 ICNIRP(International Committee on Non- Ionizing Radiation Protection) – Guidelines For Limiting Exposure To Time- varying Electric, Magnetic and Electromagnetic Fields(up to 300 GHz) OET(FCC Office of Engineering & Tech.) – Bulletin 65

12. dTR/H&D Joint Venture12 IEEE Occupational Standards

13. dTR/H&D Joint Venture13 IEEE Public Standards

14. dTR/H&D Joint Venture14 RF Exposure Mechanisms Exposure to radio frequency (RF) fields results in the absorption of energy in the body The mechanism of this energy transfer is the body acting as an antenna or, for contact currents, a semiconductive load for an RF source (i.e.RF source can be a tower, antenna, guy wire, etc)

15. dTR/H&D Joint Venture15 RF Exposure Mechanisms (continued) The direct result is RF currents flowing in the body If the currents are large enough the body temperature rises At a certain rate of energy absorption biological effects also occur

16. dTR/H&D Joint Venture16 The Electromagnetic Spectrum

17. dTR/H&D Joint Venture17 Measurement Program IEEE C95.3 Recommended Practice for the Measurements of Potentially Hazardous Electrical Fields – RF and Microwave Spatial Averaged over vertical line from 0.2 m – 2.0 m 20 cm from any object

18. dTR/H&D Joint Venture18 Spatial Averaging Measure over the area of a Human Body

19. dTR/H&D Joint Venture19 Equipment Used NARDA Model 8718B Electromagnetic Radiation Survey Meter E-Field Probe: 8742 H-Field Probe: 8732 Both “shaped” probes Conforms to IEEE Occupational Standard

20. dTR/H&D Joint Venture20 Equipment Used Holaday Contact Current Meter Clamp-on Current Transformer: HI-3702 System Readout: HI-4416 1 mA to 1 A 100 kHz to 100 MHz

21. dTR/H&D Joint Venture21 Contact Current Physical Contact with a Conductive Material

22. dTR/H&D Joint Venture22 Typical Data Sheet

23. dTR/H&D Joint Venture23 Findings Where would you expect to find high fields at a shortwave broadcasting facility?

24. dTR/H&D Joint Venture24 Transmitter Building?

25. dTR/H&D Joint Venture25 Control Room?

26. dTR/H&D Joint Venture26 Switch Matrix?

27. dTR/H&D Joint Venture27 Transmission Lines?

28. dTR/H&D Joint Venture28 Baluns?

29. dTR/H&D Joint Venture29 Antenna Ground Works?

30. dTR/H&D Joint Venture30 Antenna Near Field?

31. dTR/H&D Joint Venture31 Warning Signs

32. dTR/H&D Joint Venture32 Conclusions Closer to ground of RF conductors the higher exposure level –Under Baluns - –Open Wire Transmission Line –Antenna Ground Works Areas in main beam of antennas for 100 kW or greater within 100 meters

33. dTR/H&D Joint Venture33 Questions? Matt Folkert – matt@dlr.com Stephen Lockwood - lockwood@hatdaw.comlockwood@hatdaw.com www.dlr.comwww.dlr.com & www.hatdaw.comwww.hatdaw.com