1. RF Safety Program - Guidelines for Compliance - Understanding
Site Requirements for
Radio Frequency
Electromagnetic Fields
Robert Langston
Amateur Call W2ENY

2. OVERVIEW Requirements Dates 1997 FCC 97-303 Order
1997 OET65 Guidelines
Exposure Levels
Antenna Proximity
Exclusions and Compliance
Control of Non-Conforming Sites

3. REQUIREMENTS October 15, 1997 September 1, 2000
All new, modified and renewal sites
September 1, 2000
All sites must comply
Regions required to ensure compliance
Comply with the spirit and precautions outlined in the standards
Use common sense where not specific

4. 1997 FCC Order 97-303 The standard sets RF Exposure Levels
Occupational and General Public levels differ
Limits are averaged exposure over time
Shared responsibility for compliance in co-located sites

5. FCC SPEC and ENVIRONMENTS
Controlled Environment Limits
Exposure at some level is possible
Persons trained to know exposure is possible
Uncontrolled Environment Limits
Exposure at some lower level is possible
General Population
Oblivious to knowing they’re being exposed
1/5 the Controlled level

6. 1997 OET 65 Guidelines Evaluating Compliance with FCC rules
Prediction Methods
Multiple Transmitter Sites
Sample Calculations
Measurement Techniques
Controlling Exposure

7. EXPOSURE vs FREQUENCY

8. RF Exposure and Absorption
Maximum Exposure averaged over time
Controlled: 6 minutes
Uncontrolled: 30 minutes
Exposure measured as:
Power Density (mW/cm²)
Absorption measured as:
Thermal heating effect (Watts/Kilogram)
Sites may include other signals

9. ANTENNA PROXIMITY Behind the Antenna Above, Below or Beside Antenna
Front to Back ratio usually 30dB
Factor of 1000 times
Above, Below or Beside Antenna
Signals are greatly reduced
Isolated by 30 to 40dB
Factor of 1000 or better

10. TYPICAL ANTENNA This is a FRONT VIEW Mounted from back side
Cables attach from back or bottom
Antenna is Covered
Fiberglass or Plastic
NO ELECTRICAL SHOCK HAZARD
NO EXPOSED ELEMENTS

11. FRONT/SIDE VIEW Front to Back Ratio Side Nulls Over and Under Nulls
Above, Below and Side signals are reduced

12. Control of Fields Time Averaging Spatial Averaging
Based on Transmit vs. Receive
Duty Factors
Spatial Averaging
FCC Spec. is a whole body average
Elevate or Re-Orient Antenna
Boundary Restrictions
Fencing, Signs and Access Control

13. Duty Factor by Mode

14. Averaging

15. Averaging

16. TriBander Estimates

17. VHF/UHF Estimates

18. Sloper

19. RF SAFETY EQUIPMENT Personal Monitors Narda Survey Meter Model 8718
E-Field Probe 8722B ( % Standard)
Isotropic Polarizationless 300KHz thru 40GHz

20. So What Happens If... FCC: License Revocation
Chance about Zero
OSHA: $300 Fine per offense
Public Liability / Lawsuit
Do you love your neighbor?
Does your neighbor need the money?